Vol.:(0123456789) 1 3
Arabian Journal of Geosciences (2022) 15:1613
https://doi.org/10.1007/s12517-022-10895-9
ORIGINAL PAPER
Modeling the impact of wind shear on aerosol for flood prevention
and drought monitoring over Ethiopia
Megbar Wondie
1
· Azmeraw Alene
2
· Yesgat Enawgaw
3
Received: 6 April 2022 / Accepted: 2 October 2022
© Saudi Society for Geosciences 2022
Abstract
Extreme climate events such as heavy rain and drought occur frequently over Ethiopia because of natural and man-made
phenomena, even though modeling based on vertical wind shear (VWS) to regulate aerosol for cloud formation is quite
useful for accurate estimation of climate extremes. However, there are no previous studies of flood and drought based on
aerosol and wind shear in Ethiopia. Therefore, this paper is aimed at modeling the impact of wind shear on aerosol for flood
prevention and drought monitoring over Ethiopia. To this end, the European Center for Medium-range Weather Forecast
(ECMWF) reanalysis and Moderate Resolution Imaging Spectroradiometer (MODIS) data from 2000 to 2019 (20 years) are
analyzed. Aerosol optical depth (AOD) and Angstrom exponent (AE) models are applied to estimate aerosol concentration
and sizes. The results indicated that the mean values of VWS for two seasons, spring and summer, were 0.5 (pa/s) and 0.3
(pa/s), respectively. The strong VWS negatively correlated to cloud cover and led to drought occurrences, whereas aerosol
and cloud cover were positively correlated during weak VWS at the small-size aerosol. Owing to this, moderate VWS and
high AOD lead to the occurrence of floods in Ethiopia. Moreover, the southwest and northwest parts of Ethiopia are covered
with strong clouds due to the availability of atmospheric moisture and the local aerosol. In summer, most parts of Ethiopia
are covered by strong cloud because of weak VWS and smoke aerosols. In the Ethiopian context, there is very small fin
anthropogenic aerosol during the study period, while 5% and 1% of mixed aerosol are found during spring and summer sea-
sons respectively. Besides this, 93% and 99% of dust aerosols are found during the spring and summer seasons, respectively.
Hence, future study is quite useful to forecast the long-term climate by consideration of VWS on the regulation of aerosol
to cloud formation for drought monitoring over Ethiopia.
Keywords Aerosol Angstrom · Aerosol optical depth · Cloud · Vertical wind shear
Introduction
Ethiopia is working hard on rain-fed agriculture; even
though it has a poor strategy for adapting and mitigating
climate change (Viste and Sorteberg 2012; Bekele et al.
2016; Abebe 2017; Asfaw et al. 2018). This is because of
the natural and man-made sources in the air, and the dif-
ferent shapes and sizes of the geographic location have
changed the precipitation and temperature patterns (Asfaw
et al. 2018). Furthermore, the depletion of natural resources
and biodiversity has accelerated social poverty in a changing
landscape. Indeed, Ethiopia has dynamic landscapes with
associated different atmospheric parameters such as aerosol
concentration and vertical wind shear (VWS) that are not
included in the climate model yet. Hence, it does not have
the right methods to deal with climate change (Korecha and
Barnston 2007; Segele 2009; Kalim and Gao 2012).
Responsible Editor: Zhihua Zhang
* Megbar Wondie
megbar.radiation05@gmail.com
1
Atmospheric Physics and Radar Meteorology Research
Division at, Choke Mountain Research Institute, Debre
Markos University, Debre Markos, Ethiopia
2
Department of Physics, College of Natural
and Computational Science, Jimma University, Jimma,
Ethiopia
3
Department of Physics, College of Natural
and Computational Science, Debre Markos University,
Debre Markos, Ethiopia