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Rainfall in the Moist Tropical Caribbean Region (MTCR) in Costa Rica occurs practically throughout the year, with the quarters June–August (JJA) and December–February (DJF) concentrating over 70% of annual rainfall. Contrarily, in March–April and September–October, it rains below 100 mm per month. This seasonal rainfall behavior makes the region ideal for producing bananas (Musa spp.) and pineapple (Ananas comosus) for export (10% and 8% of total exports in 2021, respectively). A national-scale study determined that agriculture in the MTCR is one of the most vulnerable sectors to climate changes. However, the climate in this region has been poorly studied so far. This research analyzed the spatial and temporal variability of annual, monthly, and seasonal (DJF, JJA, SO) rainfall in the MTCR and how they change in the study period based on quality-checked series of daily rainfall from 28 weather stations in two periods: 1985–2009 and 1997–2019. The results show that rainfall regimes in the region are variable in space and throughout the year, with peaks occurring close to the mountain range and minimum values close to the coast. Trends were statistically significant in the period 1985–2009 with a predominance of significant positive trends in DJF and significant negative trends in SO. No significant trends (positive or negative) were observed in the period 1997–2019. JJA rainfall has uneven regional distribution and presents a positive and significant trend in the mountain region. This paper contributes to filling the knowledge gap in rainfall seasonality, variability, and trends in a region where banana and pineapple commercial plantations are fundamental to the country's economy thus providing information to decision-making in the agri-food sector to reduce the negative impacts of changing rainfall regimes. [ABSTRACT FROM AUTHOR]

Climate variations in the Caribbean, largely manifest in rainfall activity, have important consequences for the large-scale water budget, natural vegetation, and land use in the region. The wet and dry seasons will be defined, and the important roles played by the El Niño-Southern Oscillation (ENSO) and the North Atlantic Oscillation (NAO) in modulating the rainfall during these seasons will be discussed. The seasonal climate forecasts in this paper are made by 13 state of the art coupled atmosphere-ocean general circulation models (CGCMs) and by the Florida State University Synthetic Superensemble (FSUSSE), whose forecasts are obtained by a weighted combination of the individual CGCM forecasts based on a training period. The success of the models in simulating the observed 1989–2001 climatology of the various forecast parameters will be examined and linked to the models’ success in predicting the seasonal climate for individual years. Seasonal forecasts will be examined for precipitation, sea-surface temperature (SST), 2-meter air temperature, and 850 hPa u- and v-wind components during the period 1989–2001. Evaluation metrics include root mean square (RMS) error and Brier skill score. It will be shown that the FSUSSE is superior to the individual CGCMs and their ensemble mean both in simulating the 1989–2001 climatology for the various parameters and in predicting the seasonal climate of the various parameters for individual years. The seasonal climate forecasts of the FSUSSE and of the ensemble mean of the 13 state of the art CGCMs will be evaluated for years (during the period 1989–2001) that have particular ENSO and NAO signals that are known to influence Caribbean weather, particularly the rainfall. It will be shown that the FSUSSE provides superior forecasts of rainfall, SST, 2-meter air temperature, and 850 hPa u- and v-wind components during dry summers that are modulated by negative SOI and/or positive NAO indices. Such summers have become a feature of a twenty-year pattern of drought in the Caribbean region. The results presented in this paper will show that the FSUSSE is a valuable tool for forecasting rainfall and other atmospheric and oceanic variables during such periods of drought. [ABSTRACT FROM AUTHOR]

As the international community debates long-term strategies to address global warming, the issue is one of increasing concern for small island developing states. Collectively, these countries account for less than 1% of greenhouse gas emissions, yet their vulnerabilities are particularly high. This paper reviews international efforts including a regional effort on the part of 12 Caribbean countries to address this issue. For many countries and especially countries of the Caribbean and other small island developing states, vulnerabilities already exist and will only be exacerbated by accelerated global warming. Dealing with global environmental change will require good, reliable information to monitor change and assess the physical and economic impact of that change. It also will require an institutional and managerial framework that incorporates dynamic change into individual and collective decision-making processes. Small island developing states must be active players affecting long-term solutions to climate change. In the interim, targeted investments to address high priority vulnerabilities are likely to lead to no-regrets outcomes with high environmental and economic benefits. [ABSTRACT FROM AUTHOR]

Forty years (1980–2019) of reanalysis data were used to investigate climatology and trends of heat stress in the Caribbean region. Represented via the Universal Thermal Climate Index (UTCI), a multivariate thermophysiological‐relevant parameter, the highest heat stress is found to be most frequent and geographically widespread during the rainy season (August, September, and October). UTCI trends indicate an increase of more than 0.2°C·decade−1, with southern Florida and the Lesser Antilles witnessing the greatest upward rates (0.45°C·decade−1). Correlations with climate variables known to induce heat stress reveal that the increase in heat stress is driven by increases in air temperature and radiation, and decreases in wind speed. Conditions of heat danger, as depicted by the heat index (HI), have intensified since 1980 (+1.2°C) and are found to occur simultaneously to conditions of heat stress suggesting a synergy between heat illnesses and physiological responses to heat. This work also includes the analysis of the record‐breaking 2020 heat season during which the UTCI and HI achieved above average values, indicating that local populations most likely experienced heat stress and danger higher than the ones they are used to. These findings confirm the gradual intensification of heat stress in the Caribbean and aim to provide a guidance for heat‐related policies in the region. [ABSTRACT FROM AUTHOR]

Through an empirical investigation of the historical relationship between the destination climate and tourist arrivals in the Caribbean, this study presents the first revealed preference evaluation of a climate index informed by tourists' stated climatic preferences for coastal-beach tourism (i.e., a sun-sand-surf or 3S travel market). The goal of this multi-organization collaboration was to examine the potential application of a newly designed climate index—the Holiday Climate Index (HCI):Beach—for three Caribbean destinations (Antigua and Barbuda, Barbados, Saint Lucia). This paper provides an overview of the evolution of climate indices, including the development of the (HCI):Beach. To test the validity of climate indices for a beach travel market, daily climate ratings based on outputs from the Tourism Climate Index and the HCI were correlated with monthly arrivals data from Canada (a key source market) at an island destination scale. The results underscore the strength of the new index, with each destination scoring consistently higher using the HCI:Beach, including a stronger relationship (R2) between index scores and tourist arrivals. These findings demonstrate the value of combining stated and revealed preference methodologies to predict tourism demand and highlight opportunities for future research. [ABSTRACT FROM AUTHOR]

Abstract: Wave climate is highly variable on the world''s coast and its temporal changes and extremes usually imply consequences like erosion or impacts to infrastructures. Alterations in wave climate were little addressed in the four IPCC reports although variations in wave climate may cause extensive coastal impacts. Changes are also often related to climate pattern variability. This variability as well as long-term trends has been an issue of research in recent years. In the region of Latin America and the Caribbean (LAC) an understanding of wave climate and its variability is scant. In this paper we use an extensively calibrated and validated wave reanalysis to describe the wave climatology in the region at different time scales and for scalar and directional wave parameters. Long-term changes are identified in the wave heights and mean direction of the energy flux shows high spatial variability. Correlation patterns of the mean significant wave height and direction of mean energy flux lead to the detection of prominent modes of influence of several climate indices. A wave climate type approach is also used to identify wave variability along the region that allows an identification of different wave climate types in terms of wave parameters and occurrence frequency. In line with the results, the influence of El Niño events shows a higher frequency of occurrence of certain sea-states with respect to non ENSO years. We also explore how climate change affecting storm patterns may be translated into a modification of sea-state occurrence and therefore implying different consequences for coastal zones depending on local wave propagation. [Copyright &y& Elsevier]

Caribbean economies, lifestyles, activities, practices and operational cycles are intricately linked to climate, making them vulnerable to its variations and/or changes. As examples, climate extremes impact agriculture, fisheries, health, tourism, water availability, recreation, and energy usage, among other things. There is however limited incorporation of climate information in the long term developmental plans and policies of the region. This is in part due to a knowledge deficit about climate change, it's likely manifestation in the region and the possible impact on Caribbean societies. In this paper, a review of the growing bank of knowledge about Caribbean climate science; variability and change is undertaken. Insight is offered into the basic science of climate change, past trends and future projections for Caribbean climate, and the possible implications for the region. In the end a case is made for a greater response to the threats posed by climate change on the basis of the sufficiency of our current knowledge of Caribbean climate science. A general profile of what the response may look like is also offered. [ABSTRACT FROM AUTHOR]

Small island developing states in the Caribbean are among the most vulnerable countries on the planet to climate variability and climate change. In the last 3 decades, the Caribbean region has undergone frequent and intense heat waves, storms, floods, and droughts. This has had a detrimental impact on population health and well-being, including an increase in infectious disease outbreaks. Recent advances in climate science have enhanced our ability to anticipate hydrometeorological hazards and associated public health challenges. Here, we discuss progress towards bridging the gap between climate science and public health decision-making in the Caribbean to build health system resilience to extreme climatic events. We focus on the development of climate services to help manage mosquito-transmitted disease epidemics. There are numerous areas of ongoing biological research aimed at better understanding the direct and indirect impacts of climate change on the transmission of mosquito-borne diseases. Here, we emphasise additional factors that affect our ability to operationalise this biological understanding. We highlight a lack of financial resources, technical expertise, data sharing, and formalised partnerships between climate and health communities as major limiting factors to developing sustainable climate services for health. Recommendations include investing in integrated climate, health and mosquito surveillance systems, building regional and local human resource capacities, and designing national and regional cross-sectoral policies and national action plans. This will contribute towards achieving the Sustainable Development Goals (SDGs) and maximising regional development partnerships and co-benefits for improved health and well-being in the Caribbean. This Perspective article discusses progress towards bridging the gap between climate science and public health decision-making, highlighting the importance of multi-institutional and interdisciplinary collaborations to develop early warning systems for arboviral diseases in the Caribbean. [ABSTRACT FROM AUTHOR]

In groundwater-limited settings, such as Puerto Rico and other Caribbean islands, societal, ecological, and agricultural water needs depend on regular rainfall. Though long-range numerical weather predication models explicitly predict precipitation, such quantitative precipitation forecasts (QPF) critically failed to detect the historic 2015 Caribbean drought. Consequently, this work examines the feasibility of developing a drought early warning tool using the Gálvez-Davison index (GDI), a tropical convective potential index, derived from the Climate Forecast System, version 2 (CFSv2). Drought forecasts are focused on Puerto Rico's early rainfall season (ERS; April-July), which is susceptible to intrusions of strongly stable Saharan air and represents the largest source of hydroclimatic variability for the island. A fully coupled atmosphere-ocean-land model, the CFSv2 can plausibly detect the transatlantic advection of low-GDI Saharan air with multimonth lead times. The mean ERS GDI is calculated from semidaily CFSv2 forecasts beginning 1 January of each year between 2012 and 2018 and monitored as the initialization approaches 1 April. The CFSv2 demonstrates a broad region of statistically significant correlations with observed GDI across the eastern Caribbean up to 30 days prior to the ERS. During 2015, the CFSv2 forecast a low-GDI tongue extending across the Atlantic toward the Caribbean with 60-90 days lead time and placed Puerto Rico's 2015 ERS beneath the 15th percentile of all 1982-2018 ERS forecasts with up to 30 days lead time. A preliminary GDIbased QPF tool tested herein is a statistically significant improvement over climatology for the driest years. [ABSTRACT FROM AUTHOR]

This study considers long-term precipitation and temperature variability across the Caribbean using two gridded data sets (CRU TS 3.21 and GPCCv5). We look at trends across four different regions (Northern, Eastern, Southern and Western), for three different seasons (May to July, August to October and November to April) and for three different periods (1901-2012, 1951-2012 and 1979-2012). There are no century-long trends in precipitation in either data set, although all regions (with the exception of the Northern Caribbean) show decade-long periods of wetter or drier conditions. The most significant of these is for the Southern Caribbean region which was wetter than the 1961-1990 average from 1940 to 1956 and then drier from 1957 to 1965. Temperature in contrast shows statistically significant warming everywhere for the periods 1901-2012, 1951-2012 and for over half the area during 1979-2012. Data availability is a limiting issue over much of the region and we also discuss the reliability of the series we use in the context of what is known to be available in the CRU TS 3.21 data set. More station data have been collected but have either not been fully digitized yet or not made freely available both within and beyond the region. [ABSTRACT FROM AUTHOR]

ABSTRACT An index capturing the anomalies of the zonal wind at 925 hPa from 1950 to 2010 was defined to explore the relationship between the fluctuations of the Caribbean low-level jet ( CLLJ) and the main climate variability modes affecting the Intra-Americas Sea Region. El Niño Southern Oscillation ( ENSO) events, here defined using the Niño 3.4 index, are found to be the most important variability modes for the jet anomalies, in agreement with previous studies. However, the Pacific Decadal Oscillation ( PDO) and the Pacific/North American ( PNA) teleconnection pattern also show significant correlations with the CLLJ anomaly index during February. The North Atlantic Oscillation ( NAO) and the Arctic Oscillation ( AO) reveal a possible interaction with the jet anomalies that could be connected with the cold fronts and cold air surges arriving to the Caribbean basin from the Northern Hemisphere during winter. A composite technique is used to explain the correlations with the Pacific indexes. We found that ENSO events are connected to CLLJ anomalies by modulating the sea-level pressure ( SLP) near the east coast of the United States and the Aleutian Low. The pattern displayed by the SLP anomalies ( SLPa) is also associated with the PNA. During warm (cold) ENSO phases, negative (positive) anomalies in the SLP field over the east coast of North America produce cyclonic (anticyclonic) circulations at low levels. However, the ENSO signal in the SLPa and the PNA pattern are modulated by the phases of the PDO. Results indicate that when the ENSO and PDO are in phase (out of phase), the SLPa signal is enhanced (weakened or cancelled), affecting the CLLJ anomalies in both direction and intensity, also changing the spatial distribution of precipitation. [ABSTRACT FROM AUTHOR]

ABSTRACT A workshop was held at the University of the West Indies, Jamaica, in May 2012 to build capacity in climate data rescue and to enhance knowledge about climate change in the Caribbean region. Scientists brought their daily observational surface temperature and precipitation data from weather stations for an assessment of quality and homogeneity and for the calculation of climate indices helpful for studying climate change in their region. This study presents the trends in daily and extreme temperature and precipitation indices in the Caribbean region for records spanning the 1961-2010 and 1986-2010 intervals. Overall, the results show a warming of the surface air temperature at land stations. In general, the indices based on minimum temperature show stronger warming trends than indices calculated from maximum temperature. The frequency of warm days, warm nights and extreme high temperatures has increased while fewer cool days, cool nights and extreme low temperatures were found for both periods. Changes in precipitation indices are less consistent and the trends are generally weak. Small positive trends were found in annual total precipitation, daily intensity, maximum number of consecutive dry days and heavy rainfall events particularly during the period 1986-2010. Correlations between indices and the Atlantic multidecadal oscillation ( AMO) index suggest that temperature variability and, to a lesser extent, precipitation extremes are related to the AMO signal of the North Atlantic surface sea temperatures: stronger associations are found in August and September for the temperature indices and in June and October for some of the precipitation indices. [ABSTRACT FROM AUTHOR]

By the beginning of the current century, there was heightened recognition that the Caribbean is highly vulnerable to the effects of climate change. Yet, there was very little climate change science information for the region and at the scale of the small islands that make up most of the region. To fill the gap, a group of regional scientists representing three institutions and four territories (Barbados, Belize, Cuba, and Jamaica) initiated a project to provide dynamically downscaled climate change information for the Caribbean. The Providing Regional Climates for Impacts Studies (PRECIS)-Caribbean initiative was premised on a shared workload with goals to build regional capacity to provide climate change information for the region from within the region, to provide much needed climate information in the shortest possible time frame, and to create a platform for sharing the information as widely as possible. Ten years later offers the opportunity for retrospection and evaluation, particularly since a phase 2 initiative is being formulated. By both accident and design, the legacies of the PRECIS-Caribbean initiative include i) the positioning of the Caribbean to pose and answer for itself some of the emerging second-generation climate change questions; ii) the emergence of a regional template for capacity building in the sciences through cooperation; iii) an expanded regional capacity to undertake climate science; and iv) a significant body of climate change and climate science knowledge relevant to and at the scale of the Caribbean region. [ABSTRACT FROM AUTHOR]

The meteorological conditions of hurricanes passing near Puerto Rico (18N, 68W) are analyzed using composite daily reanalysis and satellite data. When an intense hurricane is present, the regional circulation is dominated by upper easterly flow over the Caribbean and central Atlantic and a surge of low-level westerly anomalies across the tropics. Warm SST anomalies extend along the coast of Venezuela, doubling the convective energy available to Caribbean hurricanes. Intensifying hurricanes tend to propagate westward with an atmospheric ridge over the Gulf Stream, in an environment with aerosol optical depth <0.6. Hurricanes form and strengthen in the east-shear phase of the Madden Julian Oscillation. Sinking motions and dry air appear in an anti-cyclonic gyre behind intensifying hurricanes. Numerical model 48-h forecasts of Caribbean hurricane tracks are analyzed over the period 2000-2010. A 'slow right' bias is found east of Puerto Rico in comparison with observed. [ABSTRACT FROM AUTHOR]

The Jordan mean tropical sounding has provided a benchmark reference for representing the climatology of the tropical North Atlantic and Caribbean Sea atmosphere for over 50 years. However, recent observations and studies have suggested that during the months of the North Atlantic hurricane season, this region of the world is affected by multiple air masses with very distinct thermodynamic and kinematic characteristics. This study examined ∼∼6000 rawinsonde observations from the Caribbean Sea region taken during the core months (July--October) of the 1995--2002 hurricane seasons. It was found that single mean soundings created from this new dataset were very similar to C. L. Jordan''s 1958 sounding work. However, recently developed multispectral satellite imagery that can track low- to midlevel dry air masses indicated that the 1995--2002 hurricane season dataset (and likely Jordan''s dataset as well) was dominated by three distinct air masses: moist tropical (MT), Saharan air layer (SAL), and midlatitude dry air intrusions (MLDAIs). Findings suggest that each sounding is associated with unique thermodynamic, kinematic, stability, and mean sea level pressure characteristics and that none of these soundings is particularly well represented by a single mean sounding such as Jordan''s. This work presents three new mean tropical soundings (MT, SAL, and MLDAI) for the tropical North Atlantic Ocean and Caribbean Sea region and includes information on their temporal variability, thermodynamics, winds, wind shear, stability, total precipitable water, and mean sea level pressure attributes. It is concluded that the new MT, SAL, and MLDAI soundings presented here provide a more robust depiction of the tropical North Atlantic and Caribbean Sea atmosphere during the Atlantic hurricane season and should replace the Jordan mean tropical sounding as the new benchmark soundings for this part of the world. [ABSTRACT FROM AUTHOR]

The study investigates the local climatological minimum of tropical cyclogenesis over the eastern Caribbean Sea. This area, colloquially known by forecasters as the "hurricane graveyard," is located within the deep tropical easterlies. Tropical disturbances emerging from the African continent usually pass through the Lesser Antilles and into the eastern Caribbean. Satellite imagery shows disturbances that frequently exhibit decreasing convection in an area bounded by the islands to the north and east, Venezuela to the south, and roughly 75°W longitude to the west. Quick Scatterometer (QuikSCAT)-derived surface winds during clear-sky conditions frequently show the presence of accelerating easterlies in the central Caribbean as part of the Caribbean low-level jet (CLLJ). Analysis of the National Centers for Environmental Prediction- National Center for Atmospheric Research (NCEP-NCAR) reanalysis project wind fields suggests the presence of an area of persistent low-level mass divergence over the eastern Caribbean. This implies a subsident regime that would weaken convection. Climatologically, this phenomenon reaches peak intensity in July, and then shifts toward the east and weakens during the latter half of the Atlantic hurricane season. This is reflected by the local minimum of tropical cyclogenesis points in the National Hurricane Center's best-track data in the early part of the season. The intensity of the low-level divergence in the eastern Caribbean is shown to be correlated with the Southern Oscillation index. The divergent low-level easterly flow can also enhance the vertical wind shear and help lower sea surface temperatures, further inhibiting tropical cyclogenesis. The local minimum of tropical cyclogenesis in this region has important implications to operational forecasting, because the vast majority of tropical cyclones in the Caribbean eventually affect surrounding landmasses. [ABSTRACT FROM AUTHOR]

This study examines the spatial variability of mean annual rainfall in the Caribbean in the satellite era 1979–2000. Intercomparisons of gridded rainfall fields from conventional stations, satellite estimators, reanalysis products, and coupled general circulation models (CGCMs) are made, with a focus on the Antilles island chain and their land–sea transitions. The rainfall products are rated for their ability to capture a number of key features, including (i) topographically enhanced precipitation over the larger western Antilles islands of Cuba, Jamaica, Hispanola, and Puerto Rico; (ii) the rain shadow west of Hispanola; (iii) the two dry zones where SSTs are low: north of Venezuela and north of the Lesser Antilles; and (iv) the wet axis extending north of Trinidad. The various monitoring and modeling systems produce gridded rainfall fields at resolutions from 50 to 280 km, from station reconstructions, satellite estimates, blended and reanalysis products, and CGCM climatologies with respect to surface forcing fields. Wet and dry biases were found in many of the reanalysis and satellite products, respectively—either over the whole Caribbean or in a certain sector. The intercomparison found some measure of consensus, but no single product is without discrepancy. High-resolution passive microwave satellite rainfall estimates [Climate Prediction Center's multisaltellite passive microwave, IR morphed product (cMOR)] appear “most representative”; however, the climatology is short (2003–07) and the field is generally drier than the consensus. Of the conventional products, decadal variability of climate interpolated rain gauges (DEKL), World Climate Research Programme's (WCRP) blended rain gauges, the Comprehensive Ocean–Atmosphere Data Set (COADS), and an operational climate anomaly monitoring system of NCEP (CAMS) perform well. Among the satellite estimators, the Global Precipitation Climatology Project's blended gauge and IR satellite (GPCP) and outgoing longwave radiation (OLR) capture the key features and ocean–island transitions. The Center for Ocean–Land–Atmosphere Studies [COLA; the coupled model, part of the Coupled Model Intercomparison Project (CMIP, phase 3)] and the climate forecast system of the NCEP (CFS) models perform reasonably, but NCAR's Parallel Climate Model (PCM; the CGCM's historical run of CMIP3) fares poorly. The version 2 hindcast of the operational Medium-Range Forecast (MRF) weather prediction model (REAN) captures the smaller wet zones and topographically enhanced features, but it does not handle the broad oceanic dry zones well, as the input from the operational climate data assimilation system of NCEP (CDAS) has a wet bias. Of the various key rainfall features, high rainfall over southern Cuba and the rain shadow west of Hispanola are poorly handled by most products. The wet axis north of Trinidad and the dry zone north of Venezuela are well represented in many climatologies. [ABSTRACT FROM AUTHOR]

The study of Caribbean climate pre-1990 focused almost exclusively on attempts to link spatial patterns in climatic variables to physical processes. Much of this research assumed a 'simple' regional climate, warm year round with a wet season dominated by tropical cyclones, but researchers soon found that a precipitation regionalization of the Caribbean was not as straightforward and simple. Consequently, a satisfactory understanding of the regional precipitation climate has eluded researchers for much of the second half of the twentieth century. Recently, with the increased availability and quality of satellite and precipitation data, researchers have begun to use gridded data sets to identify the spatial boundaries of the bimodal precipitation region and the atmospheric processes associated with the two maxima and minimum in precipitation. The findings of these most recent studies can be combined to construct a five part (North Atlantic high pressure, low level Caribbean jet, subsidence caused by Central America convection, basin wide increased wind shear, and divergence around Jamaica) conceptual Caribbean precipitation model that begins to address spatial variability in the bimodal structure of annual rainfall and the development of the midsummer minimum in precipitation. Such a regional precipitation climate model provides hypotheses to be tested and investigated in future research. Further, researchers must work towards a more effective and clear communication of the bimodal nature of Caribbean precipitation and the associated summer decrease in precipitation, integrate upper air analysis into the current working hypotheses, and further examine the interannual to interdecadal variability of the Caribbean midsummer drought for prediction purposes. [ABSTRACT FROM AUTHOR]

This article presents a study regarding the Caribbean Low Level Jet. It discusses that the Caribbean Low Level Jet is shown to be a real and dominant climatological feature of the early summer Caribbean climate, which manifests as an intensification in the trade winds in the western Caribbean basin. The study reveals the variability in the strength and zonal extent of the Caribbean Low Level Jet which can be related to zonal sea surface temperature gradients between the eastern equatorial Pacific and the north tropical and equatorial Atlantic.

The article offers information on the climatology and the future climate change in the Caribbean region based on the global general circulation. A climatological analysis on climate variations in the Caribbean is presented, followed by discussion on climate change scenarios based on the findings from Parallel Climate Model (PCM). PCM is utilized to study the impact of the global anthropogenic carbon dioxide concentration on the Caribbean climate. Evolution of Sea Surface Temperature (SST), cloud formation and solar radiative interactions affect the volume and frequency of rainfall. A future warming is predicted to reach one degree Celsius, along with increase in rain fall during the wet season, and a possible increase in tropical storm in the region.

We present a preliminary evaluation of the performance of three different cumulus parameterization schemes in the ICTP Regional Climate Model RegCM3 for two overlapping domains (termed “big” and “small”) and horizontal resolutions (50 and 25 km) in the Caribbean area during the summer (July–August–September). The cumulus parameterizations were the Grell scheme with two closure assumptions (Arakawa–Schubert and Fritsch–Chappell) and the Anthes-Kuo scheme. An additional sensitivity test was performed by comparing two different flux parameterization schemes over the ocean (Zeng and BATS). There is a systematic underestimation of air temperature and precipitation when compared with analyzed data over the big domain area. Greater (∼2 °C) and smaller (∼0.9 °C) negative temperature biases are obtained in Grell–FC and Kuo convective scheme, respectively, and intermediate values are obtained in Grell–AS. The small domain simulation produces results substantially different, both for air temperature and precipitation. Temperature estimations are better for the small domain, while the precipitation estimations are better for the big domain. An additional experiment showed that by using BATS to calculate the ocean fluxes in the big domain instead of the Zeng scheme, precipitation increases by 25% and the share of convective precipitation rose from 18% to 45% of the total, which implies a better simulation of precipitation. These changes were attributed to an increase of near surface latent heating when using BATS over the ocean. The use of BATS also reduces the cold bias by about 0.3–0.4 °C, associated with an increase of minimum temperature. The behavior of the precipitation diurnal cycle and its relation with sea breeze was investigated in the small domain experiments. Results showed that the Grell–Arakawa–Schubert closure describes better this circulation as compared with Grell–Fritsch–Chappell closure. [ABSTRACT FROM AUTHOR]