The Predictability of Saharan Dust Incursions over the Eastern Caribbean

Large quantities of dust travel from the Saharan region to the Caribbean and even as far as the Texas coast of the US every year. During high dust transport episodes, concentrations of Saharan Dust in the Caribbean regularly exceed World Health Organisation (WHO) standards for particulate matter of 2.5 microns or less (PM2.5) and 10 microns or less (PM10). Exceeding these standards, in particular the PM2.5 standard, can have serious implications for human health, national health services providers and national productivity across the region. However, numerous territories in the Caribbean do not have operational air quality monitoring programmes and do not have or enforce air quality standards for PM2.5 and PM10. The Caribbean Institute for Meteorology and Hydrology (CIMH) hosts the Pan-American Regional Centre for the World Meteorological Organization Sand and Dust Storm Warning Advisory and Assessment System (WMO SDS-WAS) and has been providing dust and air quality forecasts for the Caribbean using the Advanced Weather Research and Forecasting (WRF) model coupled with Chemistry (WRF-Chem). The WRF-Chem model is used as a coupled: (i) weather /dispersion model to simulate the release and transport of constituents; and (ii) weather/dispersion/air quality model with full interaction of chemical species to predict PM2.5, PM10, ozone (O₃), surface dust concentrations and total aerosol optical depth (AOD). Model results are compared to satellite observations and validated by available in situ dust, PM2.5 and PM10 measurements at various locations in the region including Ragged Point (Barbados), Martinique, Guadeloupe, French Guiana and Puerto Rico.

Preliminary analysis has shown that the CIMH WRF-Chem AOD correlated well with both satellite and in-situ observations. Analysis and verification of the CIMH WRF-Chem model’s ability to predict Saharan dust incursions will be presented in this research; specifically a large dust incursion over the Eastern Caribbean on April 1^st to 4^th 2017 that was predicted seven days in advance.