The North Atlantic Oscillation and the Atlantic Meridional Mode Effects on Caribbean Seasonal Precipitation Patterns

Authors: Flavia Dias De Souza Moraes*, University of Georgia, Emily Louise Pauline, University of Georgia, Ian Grey Boatman, University of Georgia, Gabriel Kooperman, University of Georgia, Thomas L Mote, University of Georgia
Topics: Climatology and Meteorology, Earth Science, Latin America
Keywords: Caribbean, Precipitation, NAO, AMM, Teleconnection
Session Type: Paper
Day: 4/5/2019
Start / End Time: 9:55 AM / 11:35 AM
Room: Marshall East, Marriott, Mezzanine Level
Presentation File: No File Uploaded

The Caribbean islands are located in Tropical North Atlantic Ocean and are divided in the Greater Antilles and the Lesser Antilles. Several papers have analyzed the effects of teleconnection patterns on the precipitation patterns of the Caribbean. However, this paper is the first of its kind to analyze the effect of both the North Atlantic Oscillation (NAO) and the Atlantic Meridional Mode (AMM) on Caribbean precipitation anomalies from 1960-2016. Spearman correlation tests compared monthly NAO and AMM indices against monthly Caribbean precipitation. The preliminary results were presented as contingency tables, which display the frequency of every possible combination (% of years) and a measurement in millimeters (mm) of the intensity of each precipitation anomaly. Preliminary results show that the NAO and AMM do have opposite relationship with Caribbean precipitation, depending on the time of year. If there is a negative wintertime NAO phase followed by a positive early rainfall season (ERS) AMM, the Caribbean can expect a statistically significant positive rainfall anomaly during boreal spring. Additionally, with a positive wintertime NAO phase and a positive late rainfall season (LRS) AMM phase in the preceding year, the dry season (Dec-Mar) precipitation anomalies will be positively affected in most of the Lesser Antilles. This relationship could make this region’s dry season less dry, which could be positive for agriculture. However, if both NAO and AMM are negative, the dry season precipitation anomalies could be even more negative than what is expected in most of the Lesser Antilles.

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