Fifteen-year Trend in African Dust Outbreaks across the eastern Caribbean
Abstract
Each year African Dust reaches the Caribbean region during late spring through early autumn. Dust Days (DD) across the eastern Caribbean, between 13° and 23° North latitude and the 61° and 71° West longitude, were identified by defining a threshold value in the midvisible Aerosol Optical Depth (AOD) retrieved from the MODerate Resolution Imaging Spectroradiometer (MODIS) between 2003 and 2018. AOD samples with timescale longer that one-year tend represented by lognormal distribution. Therefore, the 95th and 99th percentiles within the lognormal distribution were used as the point at which all subsequent values are considered as significant dust day (D95) and extreme dust day (D99). These values were validated using the Extinction Angstrom Exponent (EAE) retrieved from the AErosol RObotic NETwork (AERONET) at Cape San Juan (CSJ) in Fajardo, Puerto Rico. The Saharan Air Layer (SAL) derived from the Geostationary Operational Environmental Satellite system (GOES), backward trajectories derived from the HYbrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT), and vertical profiles of temperature, potential temperature and mixing ratios retrieved from meteorological soundings launched at the National Weather Service in San Juan, Puerto Rico were also evaluated to confirm and characterize DD.
Although MODIS data suggested that there is no clear trend in frequency of DD which are defined as days with AOD greater than 0.40 ± 0.05; the highest daily value ever observed during a month of March, May, July, September and October were set between 2017 and 2018. In addition, monthly anomalies observed during July 2018 were the highest ever recorded for any given month. Further frequency and intensity analysis is undergoing and results will be presented at the conference.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.A21I2825M
- Keywords:
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- 0305 Aerosols and particles;
- ATMOSPHERIC COMPOSITION AND STRUCTUREDE: 3305 Climate change and variability;
- ATMOSPHERIC PROCESSESDE: 3322 Land/atmosphere interactions;
- ATMOSPHERIC PROCESSESDE: 1622 Earth system modeling;
- GLOBAL CHANGE