Numerical Dust Storm Simulation Using Modified Geographical Domain and Data Assimilation: 3DVAR and 4DVAR (WRF-Chem/WRFDA)

Muhammed Eltahan,Sabah Alahmadi

doi:10.1109/access.2019.2930812

Muhammed Eltahan, Sabah Alahmadi

Open Access

https://doi.org/10.1109/access.2019.2930812

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Abstract

Dust storms have severe environmental, economic, health, weather, and climate change impacts. A severe dust storm that hit Egypt on 22 January 2004 was selected as a case study to establish an accurate numerical model to simulate dust storms over Egypt using the Weather Research Forecast with a chemistry module (WRF-Chem). Two simulation setups using WRF-Chem were conducted using two geographic domains: the first exclusively included dust sources within Egypt, while the second included an external dust source, the Bodele Depression in southwestern Chad. The first simulation was only able to capture the core of the dust plume from the internal dust source Egyptian Qattara Depression, but the second was able to capture the spatial dust distribution from both the Qattara Depression and the Bodele Depression. Moreover, the results from our second simulation model had less errors than comparable results using moderate resolution imaging spectroradiometer (MODIS). We then investigated the impact of meteorological data assimilation methods using both three-dimensional and four-dimensional variational assimilation algorithms to simulate the aerosol optical depth of the dust storm using weather research forecast data assimilation (WRFDA) framework.

Highlights

Egypt is located in the heart of the global dust belt, and meteorologists need to be able to predict dust storm occurrences and their intensities in order to forecast their impacts on human life
We investigated the impact of using the 3DVAR versus the 4DVAR data assimilation methods, using data from the National Center for Environmental Prediction (NCEP)
The Second subsection examines the influence of NCEP-ADP observations assimilation using both 3DVAR and 4DVAR algorithms on the dust storm simulation over Egypt

Summary

Introduction

Egypt is located in the heart of the global dust belt, and meteorologists need to be able to predict dust storm occurrences and their intensities in order to forecast their impacts on human life. Sand and dust storms have strong effects on planetary life [9], [22]. Dust storms have effects on climate processes and can modify the earth’s radiative equilibrium, potentially leading to equatorial tornados, which in turn can intensify dryness and affect the quality and chemistry of both air and water [16], [28]. Many physical factors affect how a dust storm will be shaped and transported, including wind speed and direction, air temperature, and precipitation [28].

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Conclusion