Estimating flash floods in arid regions is a challenge arising from the limited time preventing mitigation measures from being taken, which results in fatalities and property losses. Here, Tropical Rainfall Measuring Mission (TRMM) Multi Satellite Precipitation Analysis (TMPA) Real Time (RT) 3B2RT data are utilized in estimating floods that occurred over the city of Jeddah located in the western Kingdom of Saudi Arabia. During the 2000–2014 period, six floods that were effective on 19 days occurred in Jeddah. Three indices, constant threshold (CT), cumulative distribution functions (CDFs) and Jeddah flood index (JFI), were developed using 15-year 3-hourly 3B42RT. The CT calculated, as 10.37 mm/h, predicted flooding on 14 days, 6 of which coincided with actual flood-affected days (FADs). CDF thresholds varied between 87 and 93.74%, and JFI estimated 28 and 20 FADs where 8 and 7 matched with actual FADs, respectively. While CDF and JFI did not miss any flood event, CT missed the floods that occurred in the heavy rain months of January and December. The results are promising despite that only rainfall rates, i.e., one parameter out of various flood triggering mechanisms, i.e., soil moisture, topography and land use, are used. The simplicity of the method favors its use in TRMM follow-on missions such as the Global Precipitation Measurement Mission (GPM).
En tr In here, Ice, Cloud and Land Elevation Satellite (ICESat) altimeter data were used with MODIS snow cover maps to determine Akşehir Lake/wetland water levels which dried up in 2008. Since the water level dropped below the gage in 2004, the ICESAT-MODIS (ICEM)-based lake water levels could not be compared with gage levels. Instead, combined use of Landsat-based lake surface area studies and Akşehir Lake bathymetry (LAB) enabled ICEM assessment. ICEM and LAB differences are between -0.09m and 0.32m and close to the standard deviations (s.d.) of pure ICESat-based studies (0.02m-0.27m). The minimum and maximum water surface elevation changes of ICEM between consecutive winter and spring are 0.30m and 1.35m and are in the historical range. ICEM showed highest s.d. during October 2005, when the wind velocities were highest. Bu çalışmada, Ice, Cloud and Land Elevation Satellite (ICESat) altimetre verileri, 2008 yılında kurumuş olan Akşehir Gölü (AG)'nün su seviyelerini tespiti için MODIS kar örtüsü haritaları ile birlikte kullanılmıştır. AG’deki su seviyesi, 2004 yılında eşel seviyesinin altına düştüğü için, eşel ve ICESat-MODIS (ICEM) tabanlı göl su seviyeleri bire bir karşılaştırılamamıştır. Landsat tabanlı göl yüzey alanı çalışmaları ile AG batimetrisinin (LAB) birlikte kullanılması, ICEM tabanlı su seviyelerinin değerlendirilebilmesine imkan sağlamıştır. ICEM ve LAB arasındaki farklar -0.09m ve 0.32m olup, sadece ICESat tabanlı çalışmaların standart sapması olan 0.02m ila 0.27m değerlerine yakın olduğu görülmüştür. ICEM'in ardışık kış ve ilkbahar mevsimleri arasında hesaplanan minimum ve maksimum suyu seviyesi değişiklikleri 0.30m ve 1.35m olarak tarihsel gözlem aralığındadır. ICEM su seviyeleri, Ekim 2005'te rüzgar hızlarının en yüksek olduğu süre boyunca en yüksek standart sapmaları göstermiştir.
24 February 2016 in Arabian Journal of Geosciences