International Journal of Climatology

Under global warming the Caribbean is projected to be significantly drier by century's end during its primary rainy season from May to November. The PRECIS regional model is used to simulate the end-of-century (2071–2100) manifestation of the Caribbean Low Level Jet (CLLJ) under two Intergovernmental Panel on Climate Change (IPCC) global warming scenarios. The CLLJ is a feature of the Intra-American seas which during its July peak is dynamically linked to a brief mid-summer drying and interruption of the Caribbean rainy season. The regional model captures the CLLJ's present-day spatial and temporal characteristics reasonably well, simulating both the boreal winter (February) and summer (July) peaks. Under global warming there is an intensification of the CLLJ's core strength from May through November. The intensification is such that by October the CLLJ is of comparable core strength to its present-day peak in July. The persistence of the strong CLLJ beyond July and through November is linked to the perpetuation of a dry pattern in the Caribbean in the future. In contrast, the boreal winter manifestation of the CLLJ is largely unaltered in the future. Copyright © 2012 Royal Meteorological Society

Scenarios of rainfall and temperature changes for the period 2071–2100 under the A2 and B2 Special Report on Emissions scenarios are examined using the Hadley Centre Providing Regional Climates for Impacts Studies regional climate model. The model simulates ‘present-day’ (1979–1990) rainfall and temperature climatologies reasonably well, capturing the characteristic bimodality of Caribbean rainfall and the boreal summer maximum and winter minimum temperatures. Seasonal spatial patterns are also reproduced, but rainfall amounts are underestimated over the northern Caribbean island masses, including Cuba, Jamaica, Hispaniola and Puerto Rico. Temperatures over the region are also overestimated by 1–3 °C. For the period 2071–2100, temperatures are projected to increase across the region by 1–4 °C for all months irrespective of the scenario. The rainfall response varies with season with one of the more robust changes being an intensification of a gradient pattern in November–January, in which the northern Caribbean (i.e. north of 22°N) gets wetter and the southern Caribbean gets drier. There is also a robust June–October drying signal. The results point to changes in the regional circulation patterns due to the human-induced climate change and warrants further investigation. Copyright © 2010 Royal Meteorological Society

Singular value decomposition (SVD) techniques are used to deduce a relationship between rainfall over the Caribbean basin and oppositely signed sea-surface temperature anomalies in the Pacific and Atlantic. The analysis is done for four 3 month seasons. The first two seasons: November–January (NDJ) and February–April (FMA) encompass the Caribbean dry period, and the other two, May–July (MJJ) and August–October (ASO), include the early and late Caribbean rainy seasons. The first SVD mode for all seasons represents variability due to El Niño–southern oscillation (ENSO) and, with the exception of the later wet season, the second SVD mode represents variability due to tropical North Atlantic sea-surface temperatures. ENSO has the greatest impact during the late rainfall season (ASO) and the early dry season (NDJ), whereas the tropical Atlantic controls variability in the early rainfall season (MJJ). The configuration of concurrent but oppositely signed sea-surface temperature anomalies in the tropical Pacific and Atlantic basins is only associated with rainfall modification in the late Caribbean rainfall season (ASO) and the early Caribbean dry season (NDJ). Copyright © 2004 Royal Meteorological Society