## 3 Results
### Main Outcomes of the Top 20 Highly Cited Articles from Each Thematic Area  
#### 3.2.1 Atmosphere  
The focus of the 20 most highly cited articles in the thematic area of atmosphere are on precipitation estimates (4 articles), on dust storms (6 articles), and on the impact of coronavirus on air quality through EO (4 articles). Spatiotemporal precipitation estimates of high accuracy are essential in climate studies and in water resource planning and management, especially in regions where in situ precipitation data are not available [33; 34]. [PERSON] et al. [35] evaluated the performance of satellite-based (Tropical Rainfall Measuring Mission (TRMM) Multi-satellite Precipitation Analysis (TMPA), the Integrated Multi-satellite Retrievals for Global Precipitation Measurement (IMERG)) and model-based (European Centre for Medium-Range Weather Forecasts (ECMWF-ERA interim, ERA5)) precipitation products over varying climate and complex topography. For their evaluation, they used 256 ground-based gauge stations between 2014 and 2018 over Turkey. They reported that satellite-based products consistently performed  
Figure 6: EO applications per country and per thematic area (% of all clusters). better than model-based products in detecting and estimating daily precipitation intensities. [PERSON] et al. [36] assessed the accuracy of the IMERG products by using ground-based rain gauge observations throughout Saudi Arabia for the period from October 2015 to April 2016, based on six statistical indices. The authors highlighted the potential of IMERG products in complementing ground precipitation measurements. However, the accuracy of this product is limited in regions with high heterogeneity in the rainfall distribution and with high variability in the terrestrial topography. Similarly, [PERSON] and [PERSON] [33] found poor accuracy of IMERG products in regions with higher precipitation in Iran. The systematic error varied from less than 12% in dry regions to more than 60% in wet regions. In their study on the assessment of satellite-based precipitation measurement products over Egypt, [PERSON] et al. [37] evaluated the performance of three satellite-based high-resolution gridded rainfall datasets, namely the gauge-corrected Global Satellite Mapping of Precipitation (GSMaP), IMERG, and the Climate Hazards Group InfraRed Precipitation with Stations (CHIRPS), in the hot desert climate of Egypt with different statistical indices. Overall, CHIRPS was more accurate than the other products in estimating rainfall amounts but IMERG was better at detecting the occurrence of rainfall than CHIRPS. In order to overcome the contradictory results obtained using different statistical metrics, [PERSON] et al. [34] proposed the use of compromise programming for the selection of the appropriate gridded precipitation datasets. Dust storms are considered a common environmental phenomenon in the EMMENA region with significant impact on human health, the environment, and many associated socioeconomic factors [38; 39; 40; 41]. The study of [PERSON] et al. [42] examined the impacts of climate fluctuations on dust storm activity over the Middle East. They used aerosol optical depth, temperature, and precipitation data between 2000 and 2015, obtained from MODIS Collection, Tropical Rainfall Measuring Mission (TRMM), Global Historical Climate Network (GHCN) of the NCDC/NOAA, ECMWF, and from the Iran Meteorological Organization (IMO). Their results indicate that long-term reduction in rainfall has promoted lower soil moisture and vegetative cover, leading to more intense dust emissions. Furthermore, short-term variations in temperature in hot periods exacerbate the influence on the dust storm genesis. [PERSON] et al. [38] used a backward trajectory method on the HYSPLIT model to study the sources of dust storms over Kuwait during a 12-year period (2000-2012). The authors compared MODIS satellite observations at various latitudes (1000, 3000, 5000 m) with the HYSPLIT model and reported similar results.