Temporal evolution of summer convective activity over the Americas warm pools

Magaña, Víctor; Caetano, Ernesto

doi:10.1029/2004gl021033

Cited by 77 publications

(88 citation statements)

References 7 publications

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“…Then in June-July the expansion of the high-pressure cell begins to influence the west and northwestern portions of the Caribbean. Potentially adding to the influence of the NAHP upon the transition and northwest regions may be increased subsidence that is created by a regional teleconnection initiated by intense convection over the western part of the northeast Pacific warm pool (Magaña and Caetano, 2005). The occurrence of the MSD in July-September for the two single station regions, Venezuela and Barbados, suggest that these two locations are influenced by unique local processes that separate them from the overall circulation impacting the rest of the Caribbean MSD.…”

Section: Discussionmentioning

confidence: 99%

Spatial variability of the Caribbean mid-summer drought and relation to north Atlantic high circulation

2008

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Annual rainfall in the Caribbean exhibits a bimodal structure with two rainfall maxima (May-June and September-October) separated by what has been termed a mid-summer drought (MSD) (July-August). Despite general acceptance of the intensification and expansion of the North Atlantic High Pressure (NAHP) as the cause of the Caribbean MSD, it has been noted in several studies that the influence of the NAHP may not be consistent across the region. The purpose of this research is to better understand the Caribbean MSD by mapping the spatial co-variability of the Caribbean MSD and then determining the association between these spatial patterns and NAHP circulation. The spatial variability of the Caribbean MSD is identified through mapping of Principal Component Analysis (PCA) loadings of Caribbean MSD season rainfall time series. A correlation analysis was completed between monthly MSD region rainfall time series and measures of the NAHP to assess the degree of association between the spatial variability in the Caribbean MSD and NAHP circulation. The PCA identified six MSD regions, the northwestern Caribbean, the interior Caribbean, the eastern rim Caribbean, Coro Venezuela, Grantley Barbados, and a transition zone. The spatial pattern of the MSD regions suggests that the NAHP impacts the eastern Caribbean first and then progresses westward as the summer develops. In regard to the association between NAHP circulation and MSD region precipitation time series, correlation analysis indicates that overall, a modified Bermuda High Index (BHI) is a more effective tool in evaluating the association between the NAHP and Caribbean MSD as compared to the traditional indices, NAO EOF and BHI. Lagged correlations support previous findings that the winter preceding a particularly dry summer in the Caribbean is characterized by a strong pressure gradient on the southeastern flank of the NAHP; implying stronger Trade Winds, cooler sea surface temperatures, and reduced convective rainfall.

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Section: Discussionmentioning

confidence: 99%

Spatial variability of the Caribbean mid-summer drought and relation to north Atlantic high circulation

2008

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“…The MJO influence on regional precipitation is still an open problem for tropical research. Magaña & Caetano (2005) argued that the bimodal structure of precipitation over the Pacific side of Mesoamerica is not a form of intraseasonal variability in convective activity related to the MJO, but a characteristic of the annual cycle in precipitation. Barrett & Leslie (2009) suggest a physical relationship between the MJO and tropical cyclone activity in the Western Hemisphere.…”

Section: Madden-julian Oscillationmentioning

confidence: 99%

The easternmost tropical Pacific. Part II: Seasonal and intraseasonal modes of atmospheric variability

Amador

Durán-Quesada

Rivera

et al. 2016

RBT

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This is Part II of a two-part review about climate and climate variability focused on the Eastern Tropical Pacific (ETP) and the Caribbean Sea (CS). Both parts are aimed at providing oceanographers, marine biologists, and other ocean scientists, a guiding base for ocean-atmosphere interaction processes affecting the CS, the ETP, and the waters of Isla del Coco. Isla del Coco National Park is a Costa Rican World Heritage site. Part I analyzed the mean fields for both basins and a larger region covering 25º S -35º N, 20º W -130º W. Here we focus on a smaller area (65º W -95º W, 0º -20º N), as a complement to Part 1. Incoming solar radiation and surface energy fluxes reveal the complex nature of the ETP and CS for convective activity and precipitation on seasonal and intraseasonal time scales. Both regions are relevant as sources of evaporation and the associated moisture transport processes. The American Monsoon System influences the climate and climate variability of the ETP and CS, however, the precise way systems affect regional precipitation and transport of moisture, within the Intra Americas Sea (IAS) are not clear. Although the Caribbean Low-Level Jet (CLLJ) is known to act as a conveyor belt for moisture transport, intraseasonal and seasonal modes of the CLLJ and their interactions with other IAS systems, have to be further investigated. Trans-isthmic jets, exert a variable seasonal wind stress force over the ocean surface co-generating regions of great marine productivity. Isolated convection, the seasonal migration of the Intertropical Convergence Zone, the hurricane season, the Mid-Summer Drought, the seasonal and intraseasonal behavior of low-level jets and their interactions with transients, and the southward incursion of cold fronts contribute to regional seasonal precipitation. Many large-scale systems, such as El Niño-Southern Oscillation, the Atlantic Multidecadal Oscillation and the Madden-Julian Oscillation (MJO, also influence the variability of precipitation by modulating regional features associated with convection and precipitation. Monthly tropical storm (TS) activity in the CS and ETP basins is restricted to the period May-November, with very few cases in December. The CS presents TS peak activity during August, as well as for the number of hurricanes and major hurricanes, in contrast to the ETP that shows the same features during September. Rev. Biol. Trop. 64 (Suppl. 1): S23-S57. Epub 2016 Febrary 01.Key words: Cocos Island, Isla del Coco, seasonal and intraseasonal variability modes, Madden-Julian Oscillation, Caribbean Low-Level Jet, Chocó Jet, trans-isthmic low-level jets, atmospheric rivers.The Intra Americas Sea (IAS) is defined here as a region comprising the Gulf of Mexico (GM), the Caribbean Sea (CS), the Easternmost Tropical Pacific (ETP) and embedded continental areas. The dominant rain-producing systems of this tropical region are primarily convective in nature, however, their origin may be very broad. Convection may be the result of land and sea breeze processes, di...

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“…Rauscher et al (2008) showed that only about half the models in the AR4 MMD simulated the spatial pattern and bimodal nature of precipitation of the MSD. One of the factors contributing to the bimodal nature of summer precipitation is locally intense convective activity (Magaña and Caetano 2005;Gamble and Curtis 2008) in the region, which coarse-resolution GCMs fail to capture. This highlights the pressing need to study climate change at a regional scale so that the regional implications of these changes on mountain biosphere reserves in Central America can be examined.…”

Section: Ipcc Projections For Central Americamentioning

confidence: 99%

Climate change in Central America and Mexico: regional climate model validation and climate change projections

2011

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Central America has high biodiversity, it harbors high-value ecosystems and it's important to provide regional climate change information to assist in adaptation and mitigation work in the region. Here we study climate change projections for Central America and Mexico using a regional climate model. The model evaluation shows its success in simulating spatial and temporal variability of temperature and precipitation and also in capturing regional climate features such as the bimodal annual cycle of precipitation and the Caribbean low-level jet. A variety of climate regimes within the model domain are also better identified in the regional model simulation due to improved resolution of topographic features. Although, the model suffers from large precipitation biases, it shows improvements over the coarse-resolution driving model in simulating precipitation amounts. The model shows a dry bias in the wet season and a wet bias in the dry season suggesting that it's unable to capture the full range of precipitation variability. Projected warming under the A2 scenario is higher in the wet season than that in the dry season with the Yucatan Peninsula experiencing highest warming. A large reduction in precipitation in the wet season is projected for the region, whereas parts of Central America that receive a considerable amount of moisture in the form of orographic precipitation show significant decreases in precipitation in the dry season. Projected climatic changes can have detrimental impacts on biodiversity as they are spatially similar, but far greater in magnitude, than those observed during the El Niño events in recent decades that adversely affected species in the region.

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Temporal evolution of summer convective activity over the Americas warm pools

Cited by 77 publications

References 7 publications

Spatial variability of the Caribbean mid-summer drought and relation to north Atlantic high circulation

Spatial variability of the Caribbean mid-summer drought and relation to north Atlantic high circulation

The easternmost tropical Pacific. Part II: Seasonal and intraseasonal modes of atmospheric variability

Climate change in Central America and Mexico: regional climate model validation and climate change projections

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