Ocean Atmosphere Interaction

Scientific oceanic-atmosperic aspects of EL NIÑO 1997NIÑO -1998, considered of extraordinary magnitude, are studied and, in the same way, its effect in the climatic earthy system. This eveni can be evaluated as the most intense of our century, as a thermal anomaly in the central equatonal Pacific even 3.9' . EL NIÑO has been one of the most outstanding factors that contnbuted to the increase of the mean temperature in the earthy surface in 1997, it has reached the highest value registered in the XXth Century (more than 0,44"c), in relation to the period 1961-1990.

A parametrization of the sublimation of blowing snow has been developed. This parametrization has been used with the Canadian Land Surface Scheme (CLASS) to compare predicted results to observed snow depth measurements at three locations: Resolute, Goose Bay and Hay River. These locations demonstrate a high, moderate, and low incidence of blowing snow, respectively, according to criteria based on temperature, snow cover, and wind speed. Substantial change due to blowing snow sublimation is seen at the Resolute location. The inclusion of blowing snow sublimation generally improves the results for 23 of the 28 winters modelled. At Goose Bay the change in modelled snow depth due to blowing snow sublimation is moderate, and at Hay River it is marginal. The average snow density at Resolute modelled by CLASS is 30% less than the average measured snow density during the same period, for air temperatures below 0°C; this is likely due to wind packing of the snow. Increasing the snow density within CLASS at Resolute and including blowing snow sublimation significantly reduce the model snow depth error. At Goose Bay and Hay River, results are complicated by the possibility of missed melting events during brief warm periods and misdiagnosed precipitation.

This paper presents the synoptic and meso-scale aspects of the intense convective activity of 2 September 1974 in the Eastern Atlantic. Two main features were evident in the GATE B-scale array: a broad convective band associated with the 700-mb trough, and long and narrow lines of convection oriented SE-NW. One of these lines, which moved across the B-scale array and was penetrated by several aircraft, is described in detail. The structure of the cloud and precipitation fields, obtained from the analysis of satellite and radar data, indicates that intense precipitation occurred mainly at the leading edge of the line where new cells were continuously generating. Cross-sections through the line (from boom, aircraft and tethered balloon data) show a gust front at the surface, a downdraft region associated with the rain area, and a wind shift in the lowest 300 m. The circulations around and within this line appear to be similar to a class of tropical squall-lines studied at length by Zipser,

In order to provide better estimates of the thermal-induced stress encountered by salmon migrating to their spawning grounds, a model is used to hindcast temperatures throughout the mainstem Fraser and Thompson Rivers back to 1953. Tributary and headwater temperatures that are not available prior to 1993 are estimated with both linear regression and neural network techniques. The average root mean square difference between model temperatures and those observed at Hell's Gate, on the lower Fraser River, is computed to be 1.12°C. Historical flow and temperature observations are also used to establish patterns and trends for the Fraser River watershed. The Julian day numbers by which one-third and one-half of the integrated yearly discharge had occurred were computed and found to be progressing earlier at the rates of 0.11 and 0.09 days per year, respectively. Both values are significant at the 95% level. Average summer Hell's Gate temperatures from 1941 to 1998 are warming at the rate of 0.012°C per year, though the relatively large standard error of 0.008°C means that this result is not significantly different from zero at the 95% level. However, when the analysis is restricted to 1953 to 1998, the trend becomes 0.022°C per year and the significance level rises to 98%. An analysis of the 1953-98 atmosphere-to-river heat exchange at Kamloops and Prince George produces positive increases of 0.52 W m -2 per year and 0.90 W m -2 per year, respectively. When these trends are used to force the river temperature model, they explain approximately 35% of the 1953-98 temperature increase at Hell's Gate. An additional 20% is explained by related increases in the headwater and tributary temperatures. Though these estimates have considerable statistical uncertainty, they nevertheless suggest that most of the river warming can be attributed to climatic effects. Flow rates and river temperatures are also shown to exhibit significant differences in the summers following El Niño and La Niña winters. On average, during the summers following El Niño events, flows are approximately 800 m 3 s -1 smaller and river temperatures are approximately 0.9°C higher on the lower Fraser River. Similar estimates are produced for the major tributaries and headwaters of the Fraser and Thompson Rivers. The implications for future salmon recruitment are briefly discussed. Les observations historiques des débits et des températures sont également utilisées pour déterminer les profils et les tendances dans le bassin hydrographique du Fraser. Les nombres de jours juliens qu'il faut pour produire le tiers et la moitié des débits annuels intégrés ont été calculés et il a été constaté que ces débits se produisaient de plus en plus tôt à des taux de 0,11 et de 0,09 jour par an, respectivement. Les deux valeurs sont significatives au niveau de 95 %. Les températures moyennes d'été à Hell's Gate entre 1941 et 1998 augmentent à un rythme de 0,012°C par an, quoi que l'erreur-type relativement importante de 0,008°C implique que ce résultat n'est pas significativement différent de 0 au niveau de 95 %.

This study investigates the effects of immediate and delayed financial incentives on the probability of users downloading a mobile shopping application (app) and the moderating effects of app confidence and app usage. The study uses an online experiment with 264 participants. Findings suggest that both immediate and delayed financial incentives (i.e. discount; double point rewards) result in a higher probability of app download compared to nonfinancial incentives (i.e. personalised experience). However, there is no significant difference between the immediate and delayed rewards. The study also founds that the effects of financial incentives are reduced for higher-app-usage respondents, and perceived app confidence has a negative effect on the probability of downloading the app, which challenges the existing understanding of self-efficacy effects on app adoption. Underpinned by Achievement Goal Theory, the study advances conceptual understanding of users' motivation in technology adoption and informs strategic marketing decisions in targeting users with different motivation needs.

This experiment investigates the absorption of CO2 in a closed system to replicate open ocean buffering conditions without winds, currents, or temperature variations. A flask at STP (1 atm, 25°C) initially contains 0.5 L of air headspace (400 ppm CO2) and is modified to include 8 L of normal seawater (salinity 35 psu, alkalinity 2300 µmol/kg, pH 8.1, with flora, fauna, and nucleation sites). After increasing headspace CO2 to 800 ppm, the system equilibrates to 400 ppm in ~1 day by absorbing the added CO2 (8.184 × 10^(-6) mol) into the seawater, maintaining pH at ~8.1 due to the large seawater volume's buffering capacity. A cylindrical flask (diameter ~33 cm, height 10 cm) ensures practical design. The results demonstrate that 8 L of seawater mimics open ocean conditions, achieving rapid CO2 absorption without significant precipitation, highlighting the role of alkalinity in carbon dynamics.

The first three days were devoted to the Western Pacific International Meeting, with 80 high quality scientific presentations on the following themes: -Water masses, sea surface topography and circulation. -El Nino/Southern Oscillation 1986-87. -Theoretical and modeling studies of ENSO and related processes. -Momentum, heat and moisture fluxes between atmosphere and ocean. -Empirical studies of ENSO and climate variability. Each of the five sessions was introduced by an invited speaker who provided a review or detailed an important aspect of the session subject. From the large number of papers presented at the MeetingIWorkshop and their vigorous discussion, it is clear that there has been a significant increase over the last years in attention given to problems of oceanic and atmospheric circulation and interaction in the western tropical Pacific. As a result, there have been some major advances in our understanding of the region. With now more than 40 recent TOGA-related cruises in the western tropical Pacific, our knowledge about oceanic circulation in this region has grown. In particular more is known about the relation of the equatorial currents to those at the western boundary. The Indo-Pacific throughflow has been the subject of increasing modeling studies and it apparently does not show much of an interannual signal related to the occurrence of ENSO events. Linear analytical results concerning the reflection of Rossby waves off the gappy western boundary are now in hand, and long equatorial Rossby waves (which have been definitively observed through XBT, BT, altimetry, and CfD/ADCP measurements) do not appear to lose much energy, because of the gaps, when they reflect. Several ideas have been presented about the formation and variations of the warm pool region. Its cooling during El Nino appears more due to evaporation than advection, though the role of entrainment is still not certain. One-dimensional models suggest that the hydrological cycle plays an important role in the coupling of the atmosphere and ocean in the warm pool region, and observations show substantial variations of the salinity structures within the warm pool, leading to the conclusion that salinity effects must be included in models of the warm pool region. ID RESUME Le Symposium International sur le Pacifique Quest et Reunion de Travail TOOA COARE, qui s'est tenu en Nouvelle Caledonie au Centre QRSTQM de Noumea du 24 au 30 mai 1989, a reuni plus d'une centaine de scientifiques d'Australie, Chili, Chine, Etats Unis, France, Indonesie, Japon, Nouvelle-Zelande et du Royaume UnL L'assemblee etait composee d'un savant melange d'oceanographes et de meteorologues, specialistes des problemesde circulation tropicaleou d'interactions ocean-atmosphere. Le but principal de cet ensemble Symposium/Reunion de Travail etait de faire le point des recherches du programme international TOOA dans tout le Pacifique Tropical Quest, de coordonner les efforts croissants de recherches multinationales dans le reservoir d' eaux chaudes de cette region et de preparer au niveau international l'importante experience TOOA COARE d'interactions ocean-atmosphere. Les troispremiersjours ont ete consacres au SymposiumInternationalsur le Pacifique Quest, avec 80 presentations scientifiques de haute qualite sur les themes suivants: -masses d' eaux, topographiede surface et circulation. -El Nino/Qscillation Australe (ENSQ) 1986-87. -etudes theoriques et modelisationdes ENSQ et de ses processus. -flux de quantite de mouvement, de chaleur et de vapeur d' eau entre atmosphere et ocean. -etudes empiriques des ENSQ et de la variabilite climatique. Chacune des cinq sessions etait introduite par un orateur invite qui a effectue une revue de synthese ou detaille un aspect important du theme de la session. Le nombretresimportantdecommunicationspresenteesdurantle Symposium/Reunion de Travail et les nombreusesdiscussionsassociees,ont fait apparaitre, depuis ces dernieres annees,uninteretmarquepourlesproblemesde circulationoceaniqueet atmospheriqueet les interactions dans le Pacifique Quest. De ce fait, de serieux progres dans la comprehension de cette region ont ete realises. Avec maintenant plus de 40 croisieres recentes en rapport avec TOOA, dans le Pacifique Tropical Quest, notre connaissance sur la circulation dans cette region s'est amelioree, En particulier, la liaison entre les courants equatoriaux et ceux de la frontiere ouest est mieux connue. Les ecbanges d'eaux entre le Pacifiqueet I'Ocean Indien ont ete le sujet d'un nombre croissant de modeles et apparemment ne sont pas soumis a une importante variabilite interannuelle en rapport avec les evenements ENSQ. Les etudes analytiques lineaires,sur lareflectiondes ondesde Rossbysur la frontierepermeable (chaine d'iles) du Pacifique Quest, sont maintenant au point. Les ondes longues equatonales de Rossby (quiviennentd' etre definitivementmise en evidencegrace ades mesures XBT, BT, altimetriqueet CID/ADCP) ne semblent pas trop perdre d'energie en se reflechissant sur cette frontiere permeable, Plusieursideesont ete presenteesaproposde la formationet des variationsdu reservoir d'eaux chaudes du Pacifique Quest. Son refroidissement durant El Nino semble dO plus a l'evaporation qu'a l'advection, quoique le role de l'entrainement ne soit pas encore certain. Les modeles uni-dimensionnels suggerentque le cycle hydrologiquejoue un role important dans le couplage entre I'atmosphere et I'ocean dans la region du reservoir d' eaux chaudes. IV Les observations montrent des variations considerables de la structure de salinite dans ce reservoir et menentala conclusion que les effetsde salinite doiventetre pris en comptepour sa modelisation. n a ete montreque les difficultes rencontrees auparavant par les modelisateurs pour simuler la temperature de surface moyenne du reservoir d'eaux chaudes, pouvaient etre reduites par des modeles uniquement oceaniques, Les modeles couples suggerent que la moyenne annuelle du flux de chaleurentre I'atmosphere et l'ocean est petite « 20 W/m 2 ) dans la region du reservoir d'eaux chaudes, ce qui n'est pas en accord avec les resultats d' etudesclimatologiques. Parcontrede nouvelles etudesmettenten evidencedesproblemes avec les formules empiriques utilisees pour les climatologies, ainsi qu'un biais probable des observations utilisees pour ces analyses. Ces problemes sont peut etre uniques au reservoir d' eaux chaudes du Pacifique Ouest de par ses fortes temperatures de surface et son regime de vent faible. L'importance de l'oscillation atmospherique a30-60jours de periode et de celle des coupsdeventd' ouestpourledeveloppement desENSOa ete discutee. nn'a pasete possible d'aboutir a une conclusion ace sujet, mais des progres reels sur les statistiques et la dynamique de ces fluctuations ont ete realises. Les relations entre ces phenomenes et les fluctuations de convection atmospherique profonde, des precipitations et des flux de chaleurapparaissent marquees et de ce fait elles sont importantes en elles memes, Les observations a partir de satellites sont prometteuses. Les perspectives sont bonnes pourobtenirquelques unsdeschamps bassefrequence et grandeechelle, necessaires alacomprehension du systeme coupleocean-atmosphere. Cependant il seraindispensable de faire un effort particulier dans l'etalonnage et la validation de ces observations. Un defl plus important est l'obtention de champs ahauteresolution spatio-temporelle, apartir de capteurs satellitaires. Une des conclusions, qui revenait regulierement al'esprit des observateurs et des modelisateurs etaitquelalimitation principale alacomprehensiondesprocessusdecouplage ocean-atmosphere dans la regiondu reservoir d'eaux chaudesdu Pacifique Ouest, vient du faiblenombre d'observationsde quantitede mouvement, de chaleuret de vapeurd'eau, et dans quelques cas de la qualite des observations, La Reunion de TravailTOGA COARE, succedant au Symposium, a commence par une presentation du document preliminaire du projetscientifique U.S. COARE. En suivant les recommandations du Bureau Intergouvernemental TOGA, ce document a ete discute, ameliore etfinalement adopte, comme basepourunprojetinternational TOGACOARE, par la communaute scientifique presente a Noumea, Cela a ete possible grace aux seances plenieres et separees des groupes de travail ci-apres: -Processus des flux d'echanges air-meret des couches interfaces. -Circulation regionale atmospherique et ondes associees. -Circulation regionaleoceanique et ondes associees. De plus, les groupes de travail, ont ebauche un plan de mise en oeuvre pour I'experience COARE. Durantles sessions plenieres, plusieurs communications ont aussiete presentees sur les programmes et les techniques d'observations pouvant se rapporter a COARE. L'experience TOGA COARE proposee devrait etre capable de repondre ade nombreuses questions nonresolues quiontetemisesen avantdurantle Symposium/keunion de Travail. En particulier, l'experience COARE va offrir une occasion unique pour I'etalonnage et la validation des observations et pour developper et valider, aussi bien les modeles oceaniques et atmospheriques acouche limite que toutela gamme de modeles v coupl6s. Unenthousiasme marqu~pourl'experienee TOOA COARE a ~~expri~lorsdu Symposium/R~union de Travail. Les modelisateurs et les observateurs ont identifi~des problemes tees int6ressants enrapport aveclecouplage o=m-atmospheredanslaregion du reservoir d'eaux chaudes du Pacifique Ouest. Le projet scientifique pour COARE est presque achev~et unpremier projetdemiseenoeuvre a~~bien avanc~. La cooperation et la coordination, entreles parties oceanographique et atmosphmque de COARE, semblent se developper harmonieusement en suivant les projets des trois groupes de travail qui convergent vers une expedence efficace d'interaetion air-mer sur le reservoir d'eaux chaudes du Pacifique Ouest. vi ACKNOWLEDGMENTS The Western Pacific International Meeting and Workshop on TOGA COARE was hosted by the Groupe...

The pervasive use of smartphones has increased consumers' exposure to push notifications from mobile apps, whichwhile potentially beneficial at moderate levelscan compromise wellbeing at excessive levels (e.g., by instigating addiction). We conduct two studies to explore the impact of push notifications on smartphone addiction and its subsequent effect on consumer wellbeing, as mediated by consumer engagement. Study 1 investigates the relationship of push notifications and smartphone addiction and assesses whether engagement-based contributing (vs. consuming) behavior mitigates the adverse effect on wellbeing. The findings indicate that though push notifications are conducive to addiction, consumers' active content contributions significantly enhance wellbeing by counteracting these negative effects. Study 2 builds on Study 1 by distinguishing the effects of consumer engagement based on app type (hedonic vs. utilitarian). The results show that consumers' content-related contributing (consuming) behavior is more beneficial for hedonic (utilitarian) apps, respectively. Based on the results, we identify strategies through which consumer engagement can buffer the detrimental effects of smartphone addiction on consumer wellbeing.

Safe offshore operations and navigation in Arctic water requires reliable surveillance of icebergs. Synthetic Aperture Radar (SAR) is widely used by governments and industry to monitor iceberg locations in ice frequented waters. One of the primary challenges in using SAR data for this application is the discrimination of vessel targets from icebergs. In the context of iceberg surveillance, vessel targets are considered false alarms and the same is true of icebergs in vessel monitoring applications. The present state of the art in SAR-based vessel and iceberg discrimination is the use of machine learning to train algorithms to distinguish between vessel and iceberg backscatter. Machine learning requires the use of large datasets of validated iceberg and vessel targets, which can be costly and time consuming to collect. One solution to the problem is the use of a physical-based electromagnetic (EM) backscatter modelling of iceberg and ship targets in SAR data. The availability of such...

The wave propagation within coastal areas is strongly influenced by the coastal morphology with its islands, bars, shoals and channels. Predominant processes in this zone are shoaling, bottom friction, breaking, refraction, wind generation and to some extent diffraction of waves. The numerical formulation of these processes in standard wave models, like HISWA (HIndcast Shallow Water WAves, TU Delft), SWAN (Simulation WAves Nearshore, TU Delft) and MIKE 21 EMS (Elliptic Mild Slope, Danish Hydraulic Institute) were tested by comparing the simulation results with measurements in a wave tank and on site measurements at the North Frisian Coast of Germany. The numerical and experimental data measured in the wave flume are in very good agreement for all applied wave models proving the numerical formulation quality of bottom friction, shoaling and breaking. A comparison of numerical simulations results with SWAN and field data shows also a quite good agreement but revealed in some cases larger differences which may be contributed to the interaction of tidal currents and waves.

This study presents an overview of the El Niño–Southern Oscillation (ENSO) phenomenon and Pacific decadal variability (PDV) simulated in a multicentury preindustrial control integration of the NCAR Community Climate System Model version 4 (CCSM4) at nominal 1° latitude–longitude resolution. Several aspects of ENSO are improved in CCSM4 compared to its predecessor CCSM3, including the lengthened period (3–6 yr), the larger range of amplitude and frequency of events, and the longer duration of La Niña compared to El Niño. However, the overall magnitude of ENSO in CCSM4 is overestimated by ~30%. The simulated ENSO exhibits characteristics consistent with the delayed/recharge oscillator paradigm, including correspondence between the lengthened period and increased latitudinal width of the anomalous equatorial zonal wind stress. Global seasonal atmospheric teleconnections with accompanying impacts on precipitation and temperature are generally well simulated, although the wintertime deep...

Purpose of Review Assessment of the impact of ocean resolution in Earth System models on the mean state, variability, and future projections and discussion of prospects for improved parameterisations to represent the ocean mesoscale. Recent Findings The majority of centres participating in CMIP6 employ ocean components with resolutions of about 1 degree in their full Earth System models (eddy-parameterising models). In contrast, there are also models submitted to CMIP6 (both DECK and HighResMIP) that employ ocean components of approximately 1/4 degree and 1/10 degree (eddy-present and eddy-rich models). Evidence to date suggests that whether the ocean mesoscale is explicitly represented or parameterised affects not only the mean state of the ocean but also the climate variability and the future climate response, particularly in terms of the Atlantic meridional overturning circulation (AMOC) and the Southern Ocean. Recent developments in scale-aware parameterisations of the mesoscale are being developed and will be included in future Earth System models. Summary Although the choice of ocean resolution in Earth System models will always be limited by computational considerations, for the foreseeable future, this choice is likely to affect projections of climate variability and change as well as other aspects of the Earth System. Future Earth System models will be able to choose increased ocean resolution and/or improved parameterisation of processes to capture physical processes with greater fidelity.

Purpose of Review Assessment of the impact of ocean resolution in Earth System models on the mean state, variability, and future projections and discussion of prospects for improved parameterisations to represent the ocean mesoscale. Recent Findings The majority of centres participating in CMIP6 employ ocean components with resolutions of about 1 degree in their full Earth System models (eddy-parameterising models). In contrast, there are also models submitted to CMIP6 (both DECK and HighResMIP) that employ ocean components of approximately 1/4 degree and 1/10 degree (eddy-present and eddy-rich models). Evidence to date suggests that whether the ocean mesoscale is explicitly represented or parameterised affects not only the mean state of the ocean but also the climate variability and the future climate response, particularly in terms of the Atlantic meridional overturning circulation (AMOC) and the Southern Ocean. Recent developments in scale-aware parameterisations of the mesoscale...

Las anomalías climáticas modifican el patrón de circulación oceánica y con ello la conectividad demográfica. Sin embargo, en muchas regiones geográficas no hay suficiente evidencia de este cambio. Por ello, en el Panama Bight se realizó la comparación entre años neutrales, años El Niño y La Niña de moderada intensidad, para la Contracorriente Norecuatorial (CCNE), la Corriente Surecuatorial (CSE), la Corriente Costera (CCos) y para el remolino anticiclónico principal. Datos diarios de la topografía dinámica proporcionados por AVISO usando el producto MADT y del estrés del viento proporcionados por el Centro Europeo de Meteorología a Medio Plazo (ECMWF) se usaron para calcular la velocidad de las corrientes superficiales (promedio trimestral multianual) para los meses con mayor cantidad de huevos y larvas liberados por las especies con fase pelágica (sepnov). Se encontró que la magnitud de la velocidad para las tres corrientes oceánicas fue estadísticamente diferente entre los distintos eventos comparados, excepto para el anticiclón. Obteniendo que los valores de velocidad fueron mayores en años neutrales en relación a años Niño y Niña para la CCNE; mayores en años Niña, seguido por neutrales y Niño para la CSE; mayor en años neutrales y Niña pero menor para años Niño en la CCos; y tendencia de mayores valores en años La Niña para el remolino anticiclónico. Adicionalmente, se observó un aumento en el número de remolinos en años Niño moderado. Los resultados sugieren que la disminución en la velocidad de circulación de la CCNE y las posibles barreras creadas por remolinos ciclónicos y el remolino anticiclónico presentes cerca a la costa Suramericana podrían disminuir la dispersión pasiva de larvas y la conectividad funcional potencial entre el Pacífico Occidental, Central y Tropical Oriental, lo cual tiene implicaciones a nivel evolutivo, biogeográfico y ecológico (tasa de dispersión y efecto de rescate poblacional). Contrariamente, durante La Niña la CSE podría favorecer el transporte de larvas teleplantónicas hacia el Pacífico Central, material exportado desde la costa Suramericana mediante la CCos, ayudado por el remolino anticiclónico. Se concluye que los eventos climáticos anómalos alteran la velocidad de las corrientes oceánicas en el Panama Bight, lo cual podría afectar la conectividad funcional potencial entre septiembre y noviembre.

The vertical distribution of HCI, from 15 to 40 km, was measured with a Michelson interferometer on board the STRA TOPROBE balloon flight launched from the National Scientific Balloon Facility at Palestine, Texas, 32°N, on 8 November 1978. The mixing ratio increases from 0.1 ppbv at the troposphere near 17 km to 1.4 ppbv at the balloon float altitude of 40 km. The average mixing ratio above 40 km is 1.2 ppbv. This profile shows good overall agreement with those measured by other investigators. Comparison with a model calculation by exhibits a satisfactory fit except in the vicinity of 25-km altitude where the observed profile indicates a minimum that is not present in the model profile.

In a paper recently published in the international peer-reviewed journal Energy & Fuels, Dr. Robert H. Essenhigh (2009), Professor of Energy Conversion at The Ohio State University, addresses the residence time (RT) of anthropogenic CO2 in the air. He finds that the RT for bulk atmospheric CO2, the molecule 12CO2, is ~5 years, in good agreement with other cited sources (Segalstad, 1998), while the RT for the trace molecule 14CO2 is ~16 years. Both of these residence times are much shorter than what is claimed by the IPCC. The rising concentration of atmospheric CO2 in the last century is not consistent with supply from anthropogenic sources. Such anthropogenic sources account for less than 5% of the present atmosphere, compared to the major input/output from natural sources (~95%). Hence, anthropogenic CO2 is too small to be a significant or relevant factor in the global warming process, particularly when comparing with the far more potent greenhouse gas water vapor. The rising atmospheric CO2 is the outcome of rising temperature rather than vice versa. Correspondingly, Dr. Essenhigh concludes that the politically driven target of capture and sequestration of carbon from combustion sources would be a major and pointless waste of physical and financial resources.V.

"A DEUS essa força inabalável a qual recorremos constantemente pelo dogma chamado FÉ". "A meus queridos e amados Pais, Domingos de Nazaré Alves ("in memorian") e Lucimar Brabo Alves; e aos meus amados irmãos (Brabo, Alda, Sérgio, Carmem, Paulo, Mauro e Maria José) fontes de amor, carinho e principalmente dedicação na árdua tarefa de educar pelos ensinamentos mais nobres que um ser humano pode ter: os de preceitos morais e de respeito ao seu semelhante". "As minhas queridas, Eliane, Adja e Ivna, pela compreensão, das minhas incompreensões, nos momentos difíceis, e por acreditarem da minha importância em suas vidas. Esta conquista é muito mais de vocês". vi AGRADECIMENTOS Em especial, ao Prof. Dr. Nilson Beserra Campos, meu Orientador, pelos ensinamentos, amizade e, sobretudo pela confiança em apostar no meu potencial de trabalho.

Previous projections of the frequency of tropical cyclone genesis due to global warming, even in terms of sign of the change, depends on the chosen model simulation. Here, we systematically examine projected changes in tropical cyclones using six global atmospheric models with medium-to-high horizontal resolutions included in the sixth phase of the Coupled Model Intercomparison Project/High-Resolution Model Intercomparison Project. Changes in the frequency of tropical cyclone genesis could be broken down into the contributions from (i) the tropical cyclone seed, a depression having a closed contour of sea level pressure with a warm core and (ii) the survival rate, the ratio of the frequency of tropical cyclone genesis to that of tropical cyclone seeds. The multimodel ensemble mean indicates that tropical cyclone genesis frequencies are significantly decreased during the period 1990-2049, which is attributable to changes in tropical cyclone seeds. Analysis of the individual models shows that although most models project a more or less decreasing trend in tropical cyclone genesis frequencies and seeds, the survival rate also contributes to the result in some models. The present study indicates the usefulness of decomposition into the frequency of the tropical cyclone seeds and the survival rate to understand the cause of uncertainty in projected frequencies of tropical cyclone genesis.

Previous projections of the frequency of tropical cyclone genesis due to global warming, even in terms of sign of the change, depends on the chosen model simulation. Here, we systematically examine projected changes in tropical cyclones using six global atmospheric models with medium-to-high horizontal resolutions included in the sixth phase of the Coupled Model Intercomparison Project/High-Resolution Model Intercomparison Project. Changes in the frequency of tropical cyclone genesis could be broken down into the contributions from (i) the tropical cyclone seed, a depression having a closed contour of sea level pressure with a warm core and (ii) the survival rate, the ratio of the frequency of tropical cyclone genesis to that of tropical cyclone seeds. The multi-model ensemble mean indicates that tropical cyclone genesis frequencies are significantly decreased during the period 1990–2049, which is attributable to changes in tropical cyclone seeds. Analysis of the individual models s...

This paper explores the profound impact of User Experience (UX) design on user retention and conversion rates in mobile applications. As the mobile app market becomes increasingly competitive, understanding how UX design can enhance user satisfaction, engagement, and loyalty is crucial for developers and businesses. Through a comprehensive review of existing literature and statistical insights, this study identifies key UX design principles that contribute to improved user retention and conversion rates. Intuitive navigation, appealing visuals, performance optimization, and integration of user feedback emerge as essential components of effective UX design that drive app success. Applications that prioritize these elements foster a positive user experience, leading to higher engagement and greater retention. Additionally, UX design strategies, such as personalization and customization, have been shown to significantly increase conversion rates, demonstrating the critical role that tailored experiences play in app success. By analyzing these principles and their impact, this paper provides valuable insights for developers aiming to enhance user satisfaction, optimize app performance, and ultimately improve business outcomes.

This study presents an overview of the El Nin ˜o-Southern Oscillation (ENSO) phenomenon and Pacific decadal variability (PDV) simulated in a multicentury preindustrial control integration of the NCAR Community Climate System Model version 4 (CCSM4) at nominal 18 latitude-longitude resolution. Several aspects of ENSO are improved in CCSM4 compared to its predecessor CCSM3, including the lengthened period (3-6 yr), the larger range of amplitude and frequency of events, and the longer duration of La Nin ˜a compared to El Nin ˜o. However, the overall magnitude of ENSO in CCSM4 is overestimated by ;30%. The simulated ENSO exhibits characteristics consistent with the delayed/recharge oscillator paradigm, including correspondence between the lengthened period and increased latitudinal width of the anomalous equatorial zonal wind stress. Global seasonal atmospheric teleconnections with accompanying impacts on precipitation and temperature are generally well simulated, although the wintertime deepening of the Aleutian low erroneously persists into spring. The vertical structure of the upper-ocean temperature response to ENSO in the north and south Pacific displays a realistic seasonal evolution, with notable asymmetries between warm and cold events. The model shows evidence of atmospheric circulation precursors over the North Pacific associated with the ''seasonal footprinting mechanism,'' similar to observations. Simulated PDV exhibits a significant spectral peak around 15 yr, with generally realistic spatial pattern and magnitude. However, PDV linkages between the tropics and extratropics are weaker than observed.

How atmospheric and oceanic processes control North American precipitation variability has been extensively investigated, and yet debates remain. Here we address this question in a 50 km-resolution flux-adjusted global climate model. The high spatial resolution and flux adjustment greatly improve the model's ability to realistically simulate North American precipitation, the relevant tropical and midlatitude variability and their teleconnections. Comparing two millennium-long simulations with and without an interactive ocean, we find that the leading modes of North American precipitation variability on seasonal and longer timescales exhibit nearly identical spatial and spectral characteristics, explained fraction of total variance and associated atmospheric circulation. This finding suggests that these leading modes arise from internal atmospheric dynamics and atmosphere-land coupling. However, in the fully coupled simulation, North American precipitation variability still correlates significantly with tropical ocean variability, consistent with observations and prior literature. We find that tropical ocean variability does not create its own type of atmospheric variability but excites internal atmospheric modes of variability in midlatitudes. This oceanic impact on North American precipitation is secondary to atmospheric impacts based on correlation. However, relative to the simulation without an interactive ocean, the fully coupled simulation amplifies precipitation variance over southwest North America (SWNA) during late spring to summer by up to 90%. The amplification is caused by a stronger variability in atmospheric moisture content that is attributed to tropical Pacific sea surface temperature variability. Enhanced atmospheric moisture variations over the tropical Pacific are transported by seasonal mean southwesterly winds into SWNA, resulting in larger precipitation variance.

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A methodology is proposed for examining the effect of model parameters (assumed to be continuous) on the spatial structure of forecasts. The methodology involves several statistical methods of sampling and inference to assure the sensitivity results are statistically sound. Specifically, Latin hypercube sampling is employed to vary the model parameters, and multivariate multiple regression is used to account for spatial correlations in assessing the sensitivities. The end product is a geographic “map” of p values for each model parameter, allowing one to display and examine the spatial structure of the sensitivity. As an illustration, the effect of 11 model parameters in a mesoscale model on forecasts of convective and grid-scale precipitation, surface air temperature, and water vapor is studied. A number of spatial patterns in sensitivity are found. For example, a parameter that controls the fraction of available convective clouds and precipitation fed back to the grid scale influe...

C-FOG is a comprehensive bi-national project dealing with the formation, persistence, and dissipation (life cycle) of fog in coastal areas (coastal fog) controlled by land, marine, and atmospheric processes. Given its inherent complexity, coastal-fog literature has mainly focused on case studies, and there is a continuing need for research that integrates across processes (e.g., air–sea–land interactions, environmental flow, aerosol transport, and chemistry), dynamics (two-phase flow and turbulence), microphysics (nucleation, droplet characterization), and thermodynamics (heat transfer and phase changes) through field observations and modeling. Central to C-FOG was a field campaign in eastern Canada from 1 September to 8 October 2018, covering four land sites in Newfoundland and Nova Scotia and an adjacent coastal strip transected by the Research Vessel Hugh R. Sharp. An array of in situ, path-integrating, and remote sensing instruments gathered data across a swath of space–time sca...

Sažetak Modelske simulacije jadranske temperature i saliniteta u 2008 godini uspoređene su s priobalnim CTD mjerenjima i satelitski detektiranim površinskim temperaturama mora u cilju vrednovanja prediktivnih sposobnosti modela u priobalnom moru. S tim ciljem je Regional Ocean Modeling System (ROMS), forsiran atmosferskim modelom ALADIN (Aire Limitée Adaptation Dynamique développement Inter-National) uz razlučivanje od 8 km, primijenjen na Jadransko more uz horizontalno razlučivanje od 2 km. Mjerenja ...

Two organizations within the National Oceanic and Atmospheric Administration’s (NOAA) National Weather Service (NWS) are responsible for disseminating critical information to their customers prior to and during severe weather. The Storm Prediction Center (SPC) focuses on conducting an overall assessment of the environmental conditions on the national scale, and issues the appropriate severe weather watches. At the local level, Weather Forecast Offices (WFO) are responsible for issuing warnings to cover imminent severe weather threats. The focus of this research is primarily on the evaluation of the NWS watch and warning performance in relation to tornadic events from 1997 to 2007. Data are obtained from the NOAA Performance Management Website and the SPC watch database. The watch and warning records are matched to each tornadic event, allowing an evaluation of tornado warning performance in relation to watch type and lead time. Statistical analysis of the data reveal interesting res...

The 1883 eruption of Krakatau was a seminal event in the study of several atmospheric phenomena. This paper reviews the work that led to the first determination of the wind in the tropical stratosphere and provides some biographical background on two quite remarkable amateur scientists whose observations and analyses in the aftermath of the eruption contributed greatly to our knowledge of the stratospheric circulation. This paper will trace the path from their work in the 1880s to the mid-twentieth century when it provided the background to the surprising discovery of the stratospheric Quasibiennial Oscillation. RÉSUMÉ [Traduit par la redaction] L'éruption du Krakatoa, en 1883, a été un événement fécond pour l'étude de plusieurs phénomènes atmosphériques. Le présent article examine le travail ayant mené à la première détermination du vent dans la stratosphère tropicale et fournit des renseignements biographiques sur deux scientifiques amateurs fort remarquables dont les observations et les analyses suite à l'éruption ont grandement contribué à notre connaissance de la circulation stratosphérique. Cet article retrace le chemin séparant leur travail dans les années 1880 et le milieu du vingtième siècle, moment où il a servi de toile de fond à la surprenante découverte de l'oscillation stratosphérique quasi-biennale.

Climate change may affect ocean and ice conditions in coastal oceans and thus have significant impacts on coastal infrastructure, marine navigation, and marine ecosystems. In this study a three-dimensional ice-ocean model is developed to examine likely changes of ocean and ice conditions over the Newfoundland and Labrador Shelves in response to climate change. The model is configured with a horizontal grid of approximately 7 km and a vertical grid of 46 levels and is run from 1979 to 2069. The projection period is 2011 to 2069 under a median emission scenario A1B used by the Intergovernmental Panel on Climate Change. For the projection period, the surface atmospheric forcing fields used are from the Canadian Regional Climate Model over the North Atlantic. The open boundary conditions come from the Canadian Global Climate Model, Version 3 (CGCM3), adjusted for the 1981-2010 mean of the Simple Ocean Data Assimilation model output. The simulated fields over the 1981-2010 period have patterns consistent with observations. Over the Newfoundland and Labrador Shelves during the projection period, the model shows general trends of warming, freshening, and decreasing ice. From 2011 to 2069, the model projects that under A1B sea surface temperature will increase by 1.4°C; bottom temperature will increase by 1.6°C; sea surface salinity will decrease by 0.7; bottom salinity will decrease by 0.3; and sea-ice extent will decrease by 70%. The sea level will rise by 0.11 m at the St. John's tide-gauge station because of oceanographic change, and the freshwater transport of the Labrador Current will double as a result of freshening. The regional ice-ocean model reproduces more realistic present climate conditions and projects considerably different future climate conditions than CGCM3. RÉSUMÉ [Traduit par la rédaction] Les changements climatiques pourraient perturber les conditions marines et glaciaires dans les océans côtiers et ainsi produire des impacts considérables sur l'infrastructure côtière, la navigation maritime et les écosystèmes. Nous avons élaboré pour cette étude un modèle océan-glace tridimensionnel, afin d'examiner la modification, en réaction aux changements climatiques, des conditions marines et glaciaires sur les plateaux de Terre-Neuve et du Labrador. Le modèle possède une grille horizontale d'environ 7 kilomètres et comporte 46 niveaux. Nous l'avons exploité pour la période de 1979 à 2069. La période de projection s'étend de 2011 à 2069 et se fonde sur le scénario d'émission A1B, qu'a utilisé le Groupe d'experts intergouvernemental sur l'évolution du climat. Nous avons initialisé la période de projection avec des champs de forçage atmosphérique en surface provenant du modèle régional canadien du climat couvrant l'Atlantique Nord. Les conditions limites émanent de la version 3 du Modèle climatique global canadien (MCCG3), ajusté pour la moyenne de 1981 à 2010 des sorties du Simple Ocean Data Assimilation. Les champs simulés sur la période de 1981 à 2010 correspondent bien aux observations. Sur les plateaux de Terre-Neuve et du Labrador, durant la période de projection, le modèle montre une tendance au réchauffement, à la dessalure et à la réduction de la glace. De 2011 à 2069, le modèle prévoit, selon le scénario A1B, que la température de surface de la mer augmentera de 1,4°C, que la température au fond de la mer augmentera de 1,6°C, que la salinité de la surface diminuera de 0,7, que la salinité au fond de la mer diminuera de 0,3 et que l'étendue de la glace marine régressera de 70%. Le niveau de la mer s'élèvera de 0,11 m à la station marégraphique de St. John's, en raison des modifications océanographiques et du doublement du transport d'eau douce par le courant du Labrador en raison de la dessalure. Le modèle glace-océan régional reproduit des conditions climatiques actuelles plus réalistes que le CGCM3 et prévoit des conditions climatiques futures considérablement différentes de celui-ci.

This report documents a meeting held by the SPACC/IDYLE/ENVIFISH Working Group entitled "Spatial Approaches to the Dynamics of Coastal Pelagic Resources and their Environment in Upwelling Areas". The meeting was hosted by Marine and Coastal Management, Department of Environmental Affairs and Tourism, and was held in Cape Town from 6-8 th September 2001. The meeting was aimed at synthesizing the state of the art concerning recent theoretical achievements, analysis techniques and modelling tools used for the integration of spatial structures in the study of the dynamics of marine populations and their environments. Meeting convenors were P.

This work presents a system for automatically evaluating the interaction that exists between the atmosphere and the ocean's surface. Monitoring and evaluating the ocean's carbon exchange process is a function that requires working with a great amount of data: satellite images and in situ vessel's data. The system presented in this study focuses on computational intelligence. The study presents an intelligent system based on the use of case-based reasoning (CBR) systems and offers a distributed model for such an interaction. Moreover, the system takes into account the fact that the working environment is dynamic and therefore it requires autonomous models that evolve over time. In order to resolve this problem, an intelligent environment has been developed, based on the use of CBR systems, which are capable of handling several goals, by constructing plans from the data obtained through satellite images and research vessels, acquiring knowledge and adapting to environmental changes. The artificial intelligence system has been successfully tested in the North Atlantic Ocean, and the results obtained will be presented in this study.

March-May and December-February seasons before the onset of monsoon. The SST in the region south of 35°S is positively correlated with AIRI six, seven, and eight seasons before the onset of monsoon. A maximum correlation of 0.47 is found for the region south of 35°S, with a confidence level of 99%. Based on this correlation, we have defined SST indices for the central SIO (CSIO), the northwest of Australia (NWA), the SIO, and the Antarctic Circumpolar Current (ACC). These indices seem to be early predictors of Indian monsoons when their relationship with AIRI is examined. The predictive skill of these indices is also tested by multivariate linear regression. The consistency of this relationship is verified by the removal of the El Niño Southern Oscillation (ENSO) signal from SST data and is found to be unaffected by the ENSO signal, except in the region west of Australia.

Interannual-decadal variability in the equatorial Pacific El Nin ˜o-Southern Oscillation (ENSO) induces climate changes at global scale, but its potential influence during past global climate change is not yet well constrained. New high-resolution eastern equatorial Pacific proxy records of thermocline conditions present new evidence of strong orbital control in ENSO-like variability over the last 275,000 years. Recurrent intervals of saltier thermocline waters are associated with the dominance of La Nin ˜a-like conditions during glacial terminations, coinciding with periods of low precession and high obliquity. The parallel dominance of d 13 Cdepleted waters supports the advection of Antarctic origin waters toward the tropical thermocline. This ''oceanic tunneling'' is proposed to have reinforced orbitally induced changes in ENSO-like variability, composing a complex high-and low-latitude feedback during glacial terminations.

The carbon cycle is a crucial Earth system component affecting climate and atmospheric composition. The response of natural carbon uptake to CO2 and climate change will determine anthropogenic emissions compatible with a target CO2 pathway. For phase 5 of the Coupled Model Intercomparison Project (CMIP5), four future representative concentration pathways (RCPs) have been generated by integrated assessment models (IAMs) and used as scenarios by state-of-the-art climate models, enabling quantification of compatible carbon emissions for the four scenarios by complex, process-based models. Here, the authors present results from 15 such Earth system GCMs for future changes in land and ocean carbon storage and the implications for anthropogenic emissions. The results are consistent with the underlying scenarios but show substantial model spread. Uncertainty in land carbon uptake due to differences among models is comparable with the spread across scenarios. Model estimates of historical f...

In this paper, the sensitivity of Atmospheric and Oceanic Coupled Models (AOCMs) to the coupling method is investigated. We propose the adaptation of a Schwarz-like domain decomposition method to AOCMs. We show that the iterative process of the method ensures consistency of the coupled solution across the air-sea interface, contrarily to usual \textit{ad-hoc} algorithmic approaches. The latter are equivalent to only one iteration of a Schwarz-like iterative method, which does not provide a converged state. It is generally assumed that this lack of consistency does not affect significantly the physical properties of the solution. The relevancy of this statement is first assessed in a simplified problem, then in the realistic application of a mesoscale atmospheric model (WRF) coupled with a regional oceanic model (ROMS) to simulate the genesis and propagation of tropical cyclone Erica. Sensitivity tests to the coupling method are carried out in an ensemble approach.We show that with a...

In this study, a detailed evaluation of regional scale sublimation over two contrasting surface types is performed, based on observations and simulations from a regional climate model. New observed estimates of regional scale evaporative fractions (sublimation/precipitation) based on remotely sensed and gridded surface climate data suggest values of 0.16 and 0.09 respectively for boreal forest and agricultural regions during midwinter. While not dominating the water balance, this does indicate that sublimation is a significant component at the regional scale. On the other hand, simulated results were substantially less: 0.02 and-0.02 (i.e., net vapour deposition) respectively. Further analysis revealed that in both cases a net vapour deposition onto the ground snowpack was found, though in the forested case this was offset by a positive vapour flux off the canopy yielding a small net positive flux overall. Even over the agricultural region, sublimation was simulated during daytime in January, but this was overwhelmed by night-time frost, resulting in a net daily vapour deposition. The source of the surface vapour flux bias was further investigated. An attempt was made to enhance sublimation by increasing the sensible heat flux based on the "windless exchange" concept, which has been found helpful in studies of stand-alone snowpack models. However, in the coupled atmosphere-land surface model used here, increases in sensible heat flux into the snow were largely offset by increases in upward surface longwave flux: the net impact on sublimation and surface temperature bias was small. A proposed cold snow-vapour deposition feedback mechanism, under clear sky conditions, was determined to be unlikely for the simulation under consideration. The impact of cloud cover appears to be much more relevant to our simulation of the surface energy balance over snow. Satellite and limited surface radiation observations suggest that insufficient cloud radiative forcing simulated in the model was responsible for the excessive night-time frost. RÉSUMÉ [Traduit par la rédaction] Dans cette étude, nous faisons une évaluation détaillée de la sublimation à l'échelle régionale pour deux types de surfaces contrastants, d'après les observations et les simulations d'un modèle climatique régional. De nouvelles estimations (fondées sur des observations) des fractions d'évaporation (sublimation/précipitations) à l'échelle régionale basées sur des données de télédétection et sur les données climatiques d'une grille de surface suggèrent des valeurs de 0,16 et 0,09, respectivement, pour les régions de forêt boréale et d'agriculture au milieu de l'hiver. Sans être le facteur principal dans le bilan hydrique, ceci signifie que la sublimation en est un élément important à l'échelle régionale. D'autre part, les résultats simulés étaient nettement moindres : 0,02 et-0,02 (c.-à-d. un dépôt net de vapeur d'eau), respectivement. D'autres analyses ont révélé que, dans les deux cas, il y a eu un dépôt de vapeur d'eau sur la neige au sol, quoique dans le cas de la forêt, ce dépôt a été compensé par un flux de vapeur positif à partir de la voûte forestière, de sorte que, dans l'ensemble, le flux net est légèrement positif. Même dans la région agricole, une sublimation a été simulée durant le jour en janvier mais elle a été plus que compensée par la gelée blanche nocturne, et le résultat net est un dépôt de vapeur pour l'ensemble de la journée. Nous avons étudié davantage la source du biais de flux de vapeur à la surface. Nous avons essayé d'accroître la sublimation en augmentant le flux de chaleur sensible, d'après la notion d'« échange en l'absence de vent » qui s'est avérée utile dans des études utilisant des modèles d'accumulation de neige autonomes. Cependant, dans le modèle couplé atmosphère-terrain du terrain utilisé ici, les augmentations dans le flux de chaleur sensible vers la neige ont été largement compensées par des augmentations dans le flux ascendant de grandes longueurs d'onde depuis la surface : l'effet net sur la sublimation et le biais de température de surface s'est avéré minime. Un mécanisme proposé de rétroaction de dépôt de vapeur sur la neige froide, dans des conditions de ciel clair, a été estimé improbable pour la simulation considérée. L'effet de la couverture nuageuse semble beaucoup plus pertinent dans notre simulation du bilan énergétique de surface au-dessus de la neige. Des observations du rayonnement faites par satellite et, de façon limitée, faites depuis la surface suggèrent qu'un trop faible forçage radiatif par les nuages dans le modèle soit responsable de la formation excessive de gelée blanche nocturne.

Evidence based on numerical simulations is presented for a strong correlation between the North Atlantic Oscillation (NAO) and the North Atlantic overturning circulation. Using an ensemble of numerical experiments with a coupled ocean-atmosphere model including both natural and anthropogenic forcings, it is shown that the weakening of the thermohaline circulation (THC) could be delayed in response to a sustained upward trend in the NAO, which was observed over the last three decades of the twentieth century, 1970-99. Overall warming and enhanced horizontal transports of heat from the tropics to the subpolar North Atlantic overwhelm the NAO-induced cooling of the upper ocean layers due to enhanced fluxes of latent and sensible heat, so that the net effect of warmed surface ocean temperatures acts to increase the vertical stability of the ocean column. However, the strong westerly winds cause increased evaporation from the ocean surface, which leads to a reduced fresh water flux over the western part of the North Atlantic. Horizontal poleward transport of salinity anomalies from the tropical Atlantic is the major contributor to the increasing salinities in the sinking regions of the North Atlantic. The effect of positive salinity anomalies on surface ocean density overrides the opposing effect of enhanced warming of the ocean surface, which causes an increase in surface density in the Labrador Sea and in the ocean area south of Greenland. The increased density of the upper ocean layer leads to deeper convection in the Labrador Sea and in the western North Atlantic. With a lag of four years, the meridional overturning circulation of the North Atlantic shows strengthening as it adjusts to positive density anomalies and enhanced vertical mixing. During the positive NAO trend, the salinity-driven density instability in the upper ocean, due to both increased northward ocean transports of salinity and decreased atmospheric freshwater fluxes, results in a strengthening overturning circulation in the North Atlantic when the surface atmospheric temperature increases by 0.3°C and the ocean surface temperature warms by 0.5°to 1°C. RÉSUMÉ [Traduit par la rédaction] Nous présentons des preuves basées sur des simulations numériques d'une forte corrélation entre l'oscillation nord-atlantique (ONA) et la circulation de renversement dans l'Atlantique Nord. Au moyen d'un ensemble d'expériences numériques avec un modèle couplé océan-atmosphère qui inclut à la fois les forçages naturel et anthropique, nous montrons que l'affaiblissement de la circulation thermohaline pourrait être retardé par suite d'une tendance à la hausse soutenue dans l'ONA, tendance qui a été observée au cours des trois dernières décennies du vingtième siècle, soit la période 1970-1999. Le réchauffement général et l'augmentation des transports horizontaux de chaleur des tropiques vers l'Atlantique Nord subpolaire font plus que compenser le refroidissement causé par l'ONA des couches supérieures de l'océan à cause de l'augmentation des flux de chaleur latente et sensible, de sorte que l'effet net des températures plus élevées de la surface de l'océan fait augmenter la stabilité verticale de la colonne océanique. Cependant, les forts vents d'ouest entraînent une évaporation accrue à la surface de l'océan, ce qui mène à un flux d'eau douce réduit dans la partie ouest de l'Atlantique Nord. Le transport horizontal vers le pôle des anomalies de salinité à partir de l'Atlantique tropical est le principal contributeur de l'accroissement de salinité dans les régions de plongée d'eau de l'Atlantique Nord. L'effet des anomalies positives de salinité sur la densité de la surface océanique annule l'effet opposé du réchauffement accru de la surface océanique, ce qui entraîne un accroissement de la densité à la surface dans la mer du Labrador et dans la région de l'océan au sud du Groenland. La densité accrue des couches supérieures de l'océan occasionne une convection plus profonde dans la mer du Labrador et dans l'ouest de l'Atlantique Nord. Avec un retard de quatre ans, la circulation de renversement méridienne dans l'Atlantique Nord se renforce en réponse aux anomalies de densité positives et au mélange vertical accru.

The high-latitude ice/snow-albedo feedback is a principal element in many paleoclimate theories and global warming scenarios. The strength of this feedback is determined by the ice/snow effects on the top-of-atmosphere (TOA) albedo, which is also strongly affected by clouds. Using currently available satellite observations, we estimate the radiative effectiveness (RE) of ice and snow with regards to the TOA albedo, which we define as the change in the TOA albedo corresponding to changes of 0% to 100% in the ice or snow cover. The REs of the northern hemisphere (NH) sea ice, land snow, and southern hemisphere (SH) sea ice are found to be 0.22, 0.23 and 0.16, respectively. This means that, for an incident solar flux of about 400 W m-2 reaching the TOA in the polar latitudes in summer, local reduction in ice/snow concentrations from 100% to 0% will result in a decrease in reflected short wave radiation of approximately 80 W m-2. These changes in the TOA albedo are significant, yet smaller than the associated changes in the surface albedo. Comparison of the TOA albedo values with available surface albedo observations helps to identify the role of clouds in the RE of ice/snow. The analysis is based on the whole time-space domain where the sea ice and land snow appear, and reveals a remarkable similarity in the ice and snow RE in the areas with high sea-ice and land-snow cover variability, despite the varying nature of the surface cover, seasonality, and locations. These estimates provide a useful constraint to test current climate models.

Maximum covariance analysis (MCA) and isometric feature mapping (Isomap) are applied to investigate the spatio-temporal atmosphere-ocean interactions otherwise hidden in observational data for the period of 1979-2010. Despite an established long-term surface warming trend for the whole northern hemisphere, sea surface temperatures (SST) in the East Pacific have remained relatively constant for the period of 2001-2010. Our analysis reveals that SST anomaly probability density function of the leading two Isomap components is bimodal. We conclude that Isomap shows the existence of two distinct regimes in surface ocean temperature, resembling the break and active phases of rainfall over equatorial land areas. These regimes occurred within two separated time windows during the past three decades. Strengthening of trade winds over Pacific was coincident with the cold phase of east equatorial Pacific. This pattern was reversed during the warm phase of east equatorial Pacific. The El Niño event of 1997/1998 happened within the transition mode between these two regimes and may be a trigger for the SST changes in the Pacific. Furthermore, we suggest that Isomap, compared with MCA, provides more information about the behavior and predictability of the inter-seasonal atmosphere-ocean interactions.

High resolution meteorology-applications and services 9th EMS Annual Meeting Applications of Meteorology 9TH EUR OPE AN CON FERE NCE ON Heat waves and storm track variablity in North Atlantic and Euromediterranean region: The effects of sea-land contrast in a multimodel ensemble simulations A. Sanna (1), A. Alessandri (1), and S. Gualdi (2) (1) CMCC, Italy, (2) CMCC-INGV, Italy We present results of a study where the effects of the land-sea contrast on atmospheric circulation in the North Atlantic and Mediterranean regions are investigated. The dataset explored is formed by a set of multi-model ensemble simulations conducted with climatological SST. This should emphasize the internal climate model dynamic and its effect on the atmospheric low-frequency variability. Special interest is devoted to the Euromediterranean region, focusing on two climatic aspects: the storm track and the temperature extremes. The former is examined both in terms of eulerian and features tracking methods; the latter, investigating the circulation regimes responsible for heat waves.