Quantifying the performance of remote sensing rainfall measurement in Pahang.

Mohd Zad @ Mohd Yazid, Siti Najja (2017) Quantifying the performance of remote sensing rainfall measurement in Pahang. [Project Paper] (Submitted)

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Abstract

Remote sensing is important for generating measurement of rainfall over the vast oceans and inaccessible land areas. The Tropical Rainfall Measuring Mission (TRMM) is the first Earth Science mission dedicated to studying tropical and subtropical rainfall. Up until now, there is still limited knowledge of the accuracy of the new version TRMM 3B42-V7 despite having the advantage of high temporal resolution and large spatial coverage over oceans and land. The objectives of this study are to analyse the performance of rainfall estimation from satellites using rain gauge data by using a set of performance indicators, apply correction to satellite rainfall data to improve its representation of local scale rainfall distributions as measured by rain gauges and compare the pre-corrected scores and post-corrected scores. RGui software is used to develop algorithms to analyse the rainfall perfonnances. Mean Bias Correction (MBC) is applied to the satellite rainfall data to improve the accuracy of the satellite rainfall product. The results suggest that the altitude of the region affects the performances of the pre-corrected scores. Root Mean Squared Error (RMSE) and Mean Absolute Error (MAE) are lower at higher altitude compared to lower altitude stations. Correlation Coefficient (CC) and Nash­-Sutcliffe Efficiency (NSE) show that there is a positive but poor relationship between the rain gauge product and satellite rainfall product (0<CC<0.4) and the satellite rainfall product shows poor performances (NSE < 0.1 ). The Percent Bias (PBIAS) shows that the satellite tends to overestimate the rainfall measurement compared to rain gauge product. The Probability of Detection (POD) and Threat Score (TS) demonstrate that more than 50% of the stations have values smaller than 0.7. The Probability of False Detection (POFD) and False Alarm Rate (FAR) show that most of the stations have values lower than 0.55. In addition, the post-corrected scores are improved after MBC was applied. The improvement can be seen after comparing the pre-corrected scores and post-corrected scores of TRMM product.

Item Type:	Project Paper
Faculty:	Faculty of Engineering
Depositing User:	Ms Siti Mariam Giman
Date Deposited:	08 Nov 2024 08:37
Last Modified:	08 Nov 2024 08:37
URI:	http://psaspb.upm.edu.my/id/eprint/2126

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