Evaluation of High-Resolution Satellite-Based Real-Time and Post-Real-Time Precipitation Estimates during 2010 Extreme Flood Event in Swat River Basin, Hindukush Region

Abstract

Satellite-based real-time and post-real-time precipitation estimates of Tropical Rainfall Measuring Mission (TRMM) Multisatellite Precipitation Analysis (TMPA-3B42) were evaluated during an extreme heavy precipitation event (on 28–30 July 2010) over Swat River Basin and adjacent areas in Hindukush Region. Observations of 15 rain gauging stations were used for the evaluation of TMPA products. Results showed that the spatial pattern of precipitation in the event was generally captured by post-real-time product (3B42V7) but misplaced by real-time product (3B42RT), witnessed by a high spatial correlation coefficient for 3B42V7 (CC = 0.87) and low spatial correlation coefficient for 3B42RT (CC = 0.20). The temporal variation of the storm precipitation was not well captured by both TMPA products. 3B42V7 product underestimated the storm accumulated precipitation by 32.15%, while underestimation by 3B42RT was 66.73%. Based on the findings of this study, we suggest that the latest TMPA-based precipitation products, 3B42RT and 3B42V7, might not be able to perform well during extreme precipitation events, particularly in complex terrain regions like Hindukush Mountains. Therefore, cautions should be considered while using 3B42RT and 3B42V7 as input data source for the modelling, forecasting, and monitoring of floods and potential landslides in Hindukush Region.

Improving the Regional Applicability of Satellite Precipitation Products by Ensemble Algorithm

“…Several studies have been carried out to develop and evaluate these products in Pakistan [37][38][39][40][41] and all over the world. However, the supremacy of any specific product has not been observed in different regions with diverse climatic conditions [31,42].…”

“…The most widely used products include the Climate Prediction Center morphing technique (CMORPH) [1], the European Organization for the Exploitation of Meteorological Satellites (EUMETSAT)'s Multi-sensor Precipitation Estimate (MPE) [2], the European Centre for Medium-Range Weather Forecasts (ECMWF)'s Era-Interim product [3], the Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks (PERSIANN), the PERSIANN Cloud Classification System estimation (PERSIANN-CCS) [4], the Tropical Rainfall Measuring Mission (TRMM) Multi-satellite Precipitation Analysis products (TMPA) versions 6 (3B42-V6) and 7 (3B42-V7) [5,6] and the Integrated Multi-Satellite Retrievals for Global Precipitation Measurement (IMERG) product [7]. Numerous studies have been made to evaluate the performance of these precipitation satellite products on the regional and global scale (e.g., Asia [8][9][10][11], North and Central America [12][13][14][15][16], South America [17][18][19][20], Europe [21][22][23][24], Australia [25][26][27][28], Oceans [29,30], other [31][32][33][34][35][36] and in Pakistan [37][38][39][40][41]...…”

“…Moreover, the summer (warm) season associated with the convective structure and cold seasons with light rainfall played a decisive part in the performance evaluation of these products [32]; (vi) In Pakistan, the TRMM products provide a better performance in plain and medium elevation areas, however, resulted in overestimation in the glaciated and mountainous areas in the north and in coastal areas and in arid regions, their use is questionable [38,41]. The error associated with the satellite products showed significantly geo-topographic dependability [37][38][39][40][41]; (vii) More conclusively, the performance of these products mainly based on the variability of many factors, for example., climatic and topographic diversity, timescales (annual, seasonal, daily, and monthly), precipitation intensities, season (monsoon, winter etc.) [31,38,42] and, irrespective of significant improvements, in most of satellite precipitation products, still a region-specific assessment is necessary before any hydrological simulation, assessment, projection or outlook studies [42].…”

Evaluation and Comparison of TRMM Multi-Satellite Precipitation Products With Reference to Rain Gauge Observations in Hunza River Basin, Karakoram Range, Northern Pakistan

“…Despite the fact that 3B42V7 showed superiorities over 3B42V6 and 3B42RT, it still exhibits poor agreements with the gauge-based reference data at daily and seasonal time scales as analyzed with lower values of CC. To date, the daily and seasonal precipitation estimates derived from 3B42V7 were found to have poor correlation with the reference data in Hindukush Mountainous range [15,19], Tanzania [9], Malaysia [34], Taiwan, the U.S. Rocky Mountains and Nepal [20]. In contrast, a good correlation was found in China [28], Turkey [20], and Morocco [13].…”

“…Although some studies have also documented the performance of 3B42V7 in different regions of the world [14][15][16][17][18], limited studies have reported on its performance relative to its predecessor (3B42V6) and near real time product (3B42RT) in complex terrain regions having cryospheric environment. Thus, a river basin situated in the high mountains of Hindukush-Karakoram-Himalayan (HKH) region [15,19] has been chosen for undertaking a comprehensive and comparative assessment of TMPA products with a wide variety of statistical indicators.…”