The Caribbean Low-Level Jet and Its Relationship with Precipitation in IPCC AR4 Models

Martin, Elinor R.; Schumacher, Courtney

doi:10.1175/jcli-d-11-00134.1

Cited by 58 publications

(54 citation statements)

References 32 publications

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“…A similar bimodal cycle, however, has been extensively reported over the Greater Antilles Taylor et al, 2002;Spence et al, 2004;Ashby et al, 2005). The reduction in rainfall experienced during the summer months over the western Caribbean is argued to have a similar pattern to that in the Pacific (Martin and Schumacher, 2011). Little is known about the origins of the MSD in both, the Pacific and Caribbean.…”

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confidence: 52%

“…In addition, the stations located at the Caribbean coast present later development of the MSD, starting in average by 29 June, the minimum in 21 July, and the end at 14 August, therefore, being later and shorter in the Caribbean than in the Pacific side of Central America, showing a marked difference between the eastern and western Central America. This MSD structure over the Caribbean has been previously studied by Martin and Schumacher (2011), which concluded that the MSD in the Caribbean is controlled by different external forcing than the one operating in the Pacific sector.…”

Section: General Features Of the Msdmentioning

confidence: 65%

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Interannual variability of the midsummer drought in Central America and the connection with sea surface temperatures

et al. 2016

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Abstract. The midsummer drought (MSD) in Central America is characterised in order to create annual indexes representing the timing of its phases (start, minimum and end), and other features relevant for MSD forecasting such as the intensity and the magnitude. The MSD intensity is defined as the minimum rainfall detected during the MSD, meanwhile the magnitude is the total precipitation divided by the total days between the start and end of the MSD. It is shown that the MSD extends along the Pacific coast, however, a similar MSD structure was detected also in two stations in the Caribbean side of Central America, located in Nicaragua. The MSD intensity and magnitude show a negative relationship with Niño 3.4 and a positive relationship with the Caribbean low-level jet (CLLJ) index, however for the Caribbean stations the results were not statistically significant, which is indicating that other processes might be modulating the precipitation during the MSD over the Caribbean coast. On the other hand, the temporal variables (start, minimum and end) show low and no significant correlations with the same indexes.The results from canonical correlation analysis (CCA) show good performance to study the MSD intensity and magnitude, however, for the temporal indexes the performance is not satisfactory due to the low skill to predict the MSD phases. Moreover, we find that CCA shows potential predictability of the MSD intensity and magnitude using sea surface temperatures (SST) with leading times of up to 3 months. Using CCA as diagnostic tool it is found that during June, an SST dipole pattern upon the neighbouring waters to Central America is the main variability mode controlling the inter-annual variability of the MSD features. However, there is also evidence that the regional waters are playing an important role in the annual modulation of the MSD features. The waters in the PDO vicinity might be also controlling the rainfall during the MSD, however, exerting an opposite effect at the north and south regions of Central America.

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confidence: 52%

Section: General Features Of the Msdmentioning

confidence: 65%

Interannual variability of the midsummer drought in Central America and the connection with sea surface temperatures

et al. 2016

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“…5) so the late wet season precipitation peak coincides with the yearly maximum in SSTs and the yearly minimum in SLPs and wind speeds. Martin and Schumacher (2011) show that all the CMIP3 models successfully capture and maintain the observed features of the CLLJ, but some have difficulty in simulating its semi-annual seasonal cycle.…”

Section: Climate Model Performancementioning

confidence: 93%

A review of observed and projected changes in climate for the islands in the Caribbean

Karmalkar¹,

Taylor²,

Campbell³

et al. 2013

Atmósfera

104

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RESUMENLos cambios climáticos observados y proyectados tienen implicaciones socioeconómicas importantes para las islas del Caribe. El objetivo de este artículo es presentar información esencial sobre el cambio climá-tico -basada en estudios previos, observaciones disponibles y simulaciones de modelos climáticos-a escalas espaciales relevantes para las islas caribeñas. Se utilizan datos del modelo general de circulación (GCM) incluidos en el Proyecto de Comparación de Modelos Acoplados fase 3 (CMIP3), así como del modelo climático regional (RCM) del Centro Hadley del Reino Unido, para aportar tanto información actual como información basada en proyecciones sobre precipitaciones y temperatura en estados insulares específicos. Se utilizan observaciones reticuladas de estaciones y datos satelitales para estudiar el clima del siglo XX y evaluar el desempeño de los modelos climáticos. Con un enfoque centrado en la precipitación, también se analizan factores como la temperatura superficial del mar, la presión al nivel del mar y los vientos que influyen en las variaciones estacionales de la precipitación. La media del ensamble del CMIP3 y el RCM captan satisfactoriamente las peculiaridades de la circulación atmosférica de gran escala en la región, pero no así el ciclo estacional bimodal característico de la precipitación. La aridez en épocas de lluvias prevista en escenarios de cambio climático en la región se ha abordado en estudios previos, pero la magnitud de la variación es muy incierta en las simulaciones tanto del GCM como del RCM. La disminución proyectada es mayor al inicio de la temporada de lluvias y suprime la sequía del medio verano en el Caribe occidental. Las simulaciones del RCM muestran avances respecto del GCM, sobre todo por sus mejores representaciones de la extensión territorial, pero su desempeño depende en gran medida de la conducción del GCM. El presente estudio destaca la necesidad de contar con observaciones de alta resolución y comparar simulaciones de modelos climáticos para entender a fondo el cambio climático y su impacto en las pequeñas islas del Caribe. ABSTRACTObserved and projected changes in climate have serious socio-economic implications for the Caribbean islands. This article attempts to present basic climate change information-based on previous studies, available observations and climate model simulations-at spatial scales relevant for islands in the Caribbean. We use the General Circulation Model (GCM) data included in the Coupled Model Intercomparison Project phase 3 (CMIP3) and the UK Hadley Centre regional climate model (RCM) data to provide both present-day and scenario-based future information on precipitation and temperature for individual island states. Gridded station observations and satellite data are used to study 20th century climate and to assess the performance of climate models. With main focus on precipitation, we also discuss factors such as sea surface temperature, sea level pressure and winds that affect seasonal variations in precipitation. The CMIP3 ensemble me...

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“…These are global simulations of the atmosphere and land surface forced by observed SST, sea ice cover, and greenhouse gas concentrations. Using observed SST removes important feedbacks between the surface temperature and atmosphere, but removes the SST biases that atmosphere− ocean global climate models (GCMs) consistently produce [for example, in the western Atlantic near Barbados (27,28)]. The AMIP framework provides a test of the atmospheric component of climate models given a realistic SST distribution.…”

Section: Climate Modelsmentioning

confidence: 99%

Clouds at Barbados are representative of clouds across the trade wind regions in observations and climate models

Medeiros

Nuijens

2016

Proc. Natl. Acad. Sci. U.S.A.

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Trade wind regions cover most of the tropical oceans, and the prevailing cloud type is shallow cumulus. These small clouds are parameterized by climate models, and changes in their radiative effects strongly and directly contribute to the spread in estimates of climate sensitivity. This study investigates the structure and variability of these clouds in observations and climate models. The study builds upon recent detailed model evaluations using observations from the island of Barbados. Using a dynamical regimes framework, satellite and reanalysis products are used to compare the Barbados region and the broader tropics. It is shown that clouds in the Barbados region are similar to those across the trade wind regions, implying that observational findings from the Barbados Cloud Observatory are relevant to clouds across the tropics. The same methods are applied to climate models to evaluate the simulated clouds. The models generally capture the cloud radiative effect, but underestimate cloud cover and show an array of cloud vertical structures. Some models show strong biases in the environment of the Barbados region in summer, weakening the connection between the regional biases and those across the tropics. Even bearing that limitation in mind, it is shown that covariations of cloud and environmental properties in the models are inconsistent with observations. The models tend to misrepresent sensitivity to moisture variations and inversion characteristics. These model errors are likely connected to cloud feedback in climate projections, and highlight the importance of the representation of shallow cumulus convection.trade wind clouds | climate models | shallow cumulus | Barbados I s the cloud structure and variability observed at a single location over a long time representative of more general regimes of clouds? This is the conceit of long-term observational "super sites" but has rarely been evaluated (1, 2). This work focuses on clouds found in trade wind regions, which are mostly shallow cumulus, and asks whether findings from the Barbados Cloud Observatory (BCO) are generalizable to the broader tropics in observations and climate models. We will evaluate cloud properties and the environment in which the clouds form across 12 climate models within these regions. This emphasis on the trades is motivated by several factors: (i) Previous studies suggest these are the regions that lead to much of the spread in estimates of climate sensitivity (3, 4), (ii) there is a dearth of evaluation of shallow cumulus in climate models (5), and (iii) space-based and ground-based observations of the trades have recently become available (6-8). This focus on trade wind regions is unique but builds upon previous, broader model evaluations that have, among other things, shown improvements in near-global cloud properties in the latest generation of climate models (9) and provided an overview of the vertical structure of cloud fraction (CF) and cloud water content over tropical oceans (10). Ref. 11 explores low-level, tropical clou...

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The Caribbean Low-Level Jet and Its Relationship with Precipitation in IPCC AR4 Models

Cited by 58 publications

References 32 publications

Interannual variability of the midsummer drought in Central America and the connection with sea surface temperatures

Interannual variability of the midsummer drought in Central America and the connection with sea surface temperatures

A review of observed and projected changes in climate for the islands in the Caribbean

Clouds at Barbados are representative of clouds across the trade wind regions in observations and climate models

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