Performance of TRMM Product in Quantifying Frequency and Intensity of Precipitation during Daytime and Nighttime across China

Yun Li,Kaicun Wang,Guocan Wu,Bin Guo,Chunming Shi

doi:10.3390/rs12040740

Abstract

The Tropical Rainfall Measurement Mission (TRMM) satellite is the first to be designed to measure precipitation, and its precipitation products have been assessed in a variety of ways. Data for its post-real-time level 2 product (3B42) performed well in terms of the precipitation amount at the monthly scale because they were corrected by a precipitation dataset that was gauged every month. However, the performance of this dataset in terms of precipitation frequency and intensity is still not ideal. To this end, TRMM 3B42 products were evaluated using precipitation data from 747 meteorological stations over mainland China in this study. The Pearson’s correlation coefficient (CC), relative bias (RB), and relative error (RE) were used to assess the capability of TRMM products in terms of estimating the frequency, intensity, and amount of precipitation for different categories of precipitation during nighttime and daytime in a multiscale analysis (including interannual variation, seasonal cycles, and spatial distribution). Our results showed the following: (1) The 3B42 products reproduced interannual trends of the frequency and amount of precipitation (except for trace precipitation) with an average correlation coefficient of 0.84. (2) 3B42 performed well at calculating the annual and monthly precipitation amount, but performed poorly for frequency and even worse for intensity. The biases in these two properties canceled out, however, which led to a better estimate of the amount. (3) 3B42 represented the distribution of the subdaily amount of precipitation over a majority of the regions in the east, but did not perform well on the Tibetan Plateau or in northwest China. The performance of 3B42, as detailed in this study, can serve as valuable guidance to data users and algorithm developers.

Highlights

Precipitation is among the most important meteorological and climatic variables [1]
Tropical Rainfall Measurement Mission (TRMM) 3B42 products roughly reproduced the interannual trends of the precipitation frequencies over mainland China in the last two decades, excluding the frequency of trace amounts of rain (Figure 2a1,b1)
TRMM had the strongest correlation with gauge data in terms of moderate and large amounts of rain (CC > 0.9), a moderate correlation for small amounts of rain (CC = 0.562 and CC = 0.470 for nighttime and daytime, respectively), and an insignificant correlation for trace amounts of rain

Summary

Introduction

Precipitation is among the most important meteorological and climatic variables [1] It features complex temporal and spatial variations, and is a key factor in regional weather changes and the formation of the global climate [2,3]. Current methods for measuring precipitation include ground observations from rain gauges and radars, and estimates inferred from satellite sensors [7,8]. Rain gauge observations constitute the most primitive and direct method for measuring precipitation, but are often restricted by the number and uneven spatial distribution of meteorological stations [9], especially in developing countries and areas with complex terrains [10]. Satellite precipitation products have received increasing research interest owing to their wide range of observations, high spatiotemporal resolution, free availability, and real-time access to data [14,15]

Methods

Results

Discussion

Conclusion