Assessment of GPM and TRMM Precipitation Products over Singapore

Abstract

The evaluation of satellite precipitation products (SPPs) at regional and local scales is essential in improving satellite-based algorithms and sensors, as well as in providing valuable guidance when choosing alternative precipitation data for the local community. The Tropical Rainfall Measuring Mission (TRMM) has made significant contributions to the development of various SPPs since its launch in 1997. The Global Precipitation Measurement (GPM) mission launched in 2014 and is expected to continue the success of TRMM. During the transition from the TRMM era to the GPM era, it is necessary to assess GPM products and make comparisons with TRMM products in different regions to achieve a global view of the performance of GPM products. To this end, this study aims to assess the capability of the latest Integrated Multi-satellite Retrievals for GPM (IMERG) and two TRMM Multisatellite Precipitation Analysis (TMPA) products (TMPA 3B42 and TMPA 3B42RT) in estimating precipitation over Singapore that represents a typical tropical region. The evaluation was conducted at daily, monthly, seasonal and annual scales from 1 April 2014 to 31 January 2016. The capability of SPPs in detecting rainy/non-rainy days and different precipitation classes was also evaluated. The findings showed that: (1) all SPPs correlated well with measurements from gauges at the monthly scale, but moderately at the daily scale; (2) SPPs performed better in the northeast monsoon season (1 December-15 March) than in the inter-monsoon 1 ((3) IMERG had better performance in the characterization of spatial precipitation variability and precipitation detection capability compared to the TMPA products; (4) for the daily precipitation estimates, IMERG had the lowest systematic bias, followed by 3B42 and 3B42RT; and (5) most of the SPPs overestimated moderate precipitation events (1-20 mm/day), while underestimating light (0.1-1 mm/day) and heavy (>20 mm/day) precipitation events. Overall, IMERG is superior but with only slight improvement compared to the TMPA products over Singapore. This study is one of the earliest assessments of IMERG and a comparison of it with TMPA products in Singapore. Our findings were compared with existing studies conducted in other regions, and some limitations of the IMERG and TMPA products in this tropical region were identified and discussed. This study provides an added value to the understanding of the global performance of the IMERG product.

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

“…In contrast, a good correlation was found in China [28], Turkey [20], and Morocco [13]. A good correlation in these regions may be because more gauging stations were used in bias correction algorithm of TMPA products [5]. Selection of the limited number of reference ground-based gauging station in the bias correction algorithms of TMPA products could be one of the potential reasons behind poor correlations of TMPA products with reference gauges data in the northern Pakistan.…”

“…The upgraded algorithm used in 3B42V7 combines the estimates from the MW Humidity Sounder (MWHS), TRMM Precipitation Radar (TPR), SSMI, GPCC, and National Climatic Data Centre (NCDC). After the success of TRMM project, NASA and JAXA launched a successor to TMPA products in early 2014, known as GPM product (not included in this study), by combining the algorithm of upgraded TMPA product with Climate Prediction Centre Morphing technique (CMORPH) and Precipitation Estimation from the Remotely Sensed Information Using Artificial Network (PERSIANN) [5]. Therefore, comprehensive assessments and comparisons of the performance of the upgraded TMPA algorithm relative to its predecessor and real time versions in different regions, precipitation patterns and topographic conditions would be valuable for algorithm developers, particularly for GPM, as well as satellite-based precipitation data users.…”

Accuracy Evaluation of Two High-Resolution Satellite-Based Rainfall Products: TRMM 3B42V7 and CMORPH in Shanghai

“…The results show that the relative magnitude of TRMM rain accumulation compared to rain gauge accumulation is smaller for higher rainfall intensity events. Tan and Zheng [45] evaluated the detection capability of two TRMM products (3B42 and 3B42RT) in Singapore, and found that satellite products do not capture Table 1). …”

Multiscale Comparative Evaluation of the GPM IMERG v5 and TRMM 3B42 v7 Precipitation Products from 2015 to 2017 over a Climate Transition Area of China

“…To evaluate the performance of TRMM 3B42 v7 and GPM IMERG v5 precipitation products and ensure proper error analysis on a grid basis at multiple scales over the basin, the specified location or pixel for each rain gauge was checked, and then, the spatial-temporal coincident satellite pixel with corresponding gauges was evaluated [15,20]. Only the satellite grids that covered at least one rain gauge were evaluated, and the other grids with no rain gauges were excluded from the evaluation.…”