Evaluation of Six High-Resolution Satellite and Ground-Based Precipitation Products over Malaysia

Mou Tan,Ab Ibrahim,Arthur Cracknell,Vincent Chaplot,Zheng Duan

doi:10.3390/rs70201504

Abstract

Satellite precipitation products (SPPs) potentially constitute an alternative to sparse rain gauge networks for assessing the spatial distribution of precipitation. However, applications of these products are still limited due to the lack of robust quality assessment. This study compares daily, monthly, seasonal, and annual rainfall amount at 342 rain gauges over Malaysia to estimations using five SPPs (3B42RT, 3B42V7, GPCP-1DD, PERSIANN-CDR, and CMORPH) and a ground-based precipitation product (APHRODITE). The performance of the precipitation products was evaluated from 2003 to 2007 using continuous (RMSE, R2, ME, MAE, and RB) and categorical (ACC, POD, FAR, CSI, and HSS) statistical approaches. Overall, 3B42V7 and APHRODITE performed the best, while the worst performance was shown by GPCP-1DD. 3B42RT, 3B42V7, and PERSIANN-CDR slightly overestimated observed precipitation by 2%, 4.7%, and 2.1%, respectively. By contrast, APHRODITE and CMORPH significantly underestimated precipitations by 19.7% and 13.2%, respectively, whereas GPCP-1DD only slightly underestimated by 2.8%. All six precipitation products performed better in the northeast monsoon than in the southwest monsoon. The better performances occurred in eastern and southern Peninsular Malaysia and in the north of East Malaysia, which receives higher rainfall during the northeast monsoon, whereas poor performances occurred in the western and dryer Peninsular Malaysia. All precipitation products underestimated the no/tiny (<1 mm/day) and extreme (≥20 mm/day) rainfall events, while they overestimated low (1–20 mm/day) rainfall events. 3B42RT and 3B42V7 showed the best ability to detect precipitation amounts with the highest HSS value (0.36). Precipitations during flood events such as those which occurred in late 2006 and early 2007 were estimated the best by 3B42RT and 3B42V7, as shown by an R2 value ranging from 0.49 to 0.88 and 0.52 to 0.86, respectively. These results on SPPs’ uncertainties and their potential controls might allow sensor and algorithm developers to deliver better products for improved rainfall estimation and thus improved water management.

Highlights

Precipitation is an important input of water in the hydrological cycle and is the main source of catchment water [1]
Precipitation data within the catchment area come from direct measurement at gauges
The observed mean annual precipitation (MAP) for Malaysia was 2852 mm/year, with a maximum value of more than 4800 mm/year recorded by a rain gauge in southern East Malaysia (EM) and a minimum of about 500 mm/year in middle Peninsular Malaysia (PM) (Figure 2g)

Summary

Introduction

Precipitation is an important input of water in the hydrological cycle and is the main source of catchment water [1]. Accurate and reliable precipitation information is necessary to ensure better water resource management and decision-making in the various areas using water, such as agriculture, industries, and cities. Precipitation data within the catchment area come from direct measurement at gauges. Apart from this, precipitation is recorded using other ground-based observations such as weather radars and disdrometers, and these techniques are often cited as the most reliable sources of precipitation information [7]. Precipitation data obtained using ground-based observations can be very accurate; there are some limitations associated with their cost and the insufficient density of ground stations, especially in the less accessible mountain regions of the world [8]

Objectives

Methods

Results

Conclusion