Spatio-Temporal Assessment of Global Precipitation Products over the Largest Agriculture Region in Pakistan

Zain Nawaz,Naima Nawaz,Xin Li,Rabia Gull,Abdelrazek Elnashar,Yingying Chen

doi:10.3390/rs12213650

Abstract

Spatial and temporal precipitation data acquisition is highly important for hydro-meteorological applications. Gridded precipitation products (GPPs) offer an opportunity to estimate precipitation at different time and resolution. Though, the products have numerous discrepancies that need to be evaluated against in-situ records. The present study is the first of its kind to highlight the performance evaluation of gauge based (GB) and satellite based (SB) GPPs at annual, winter, and summer monsoon scale by using multiple statistical approach during the period of 1979–2017 and 2003–2017, respectively. The result revealed that the temporal magnitude of all the GPPs was different and deviate up to 100–200 mm with overall spatial pattern of underestimation (GB product) and overestimation (SB product) from north to south gradient. The degree of accuracy of GB products with observed precipitation decreases with the increase in the magnitude of precipitation and vice versa for SB precipitation products. Furthermore, the observed precipitation revealed the positive trend with multiple turning points during the period 1979–2005. However, the gentle increase with no obvious break point has been detected during the period of 2005–2017. The large inter-annual variability and trends slope of the reference data series were well captured by Global Precipitation Climatology Centre (GPCC) and Tropical Rainfall Measuring Mission (TRMM) products and outperformed the relative GPPs in terms of higher R2 values of ≥ 0.90 and lower values of estimated RME ≤ 25% at annual and summer monsoon season. However, Climate Research Unit (CRU) performed better during winter estimates as compared with in-situ records. In view of significant error and discrepancies, regional correction factors for each GPPs were introduced that can be useful for future concerned projects over the study region. The study highlights the importance of evaluation by the careful selection of potential GPPs for the future hydro-climate studies over the similar regions like Punjab Province.

Highlights

Accurate and reliable estimates of global climate patterns are directly associated with the regional variation in precipitation [1]
The temporal trends indicated that the annual precipitation amounts that were underestimated by the Gridded precipitation products (GPPs) with the exception of Tropical Rainfall Measuring Mission (TRMM) and PERSIANN-CDR products, which overestimated the magnitude as compared with the reference data
The most accurate and consistent spatial pattern was observed in Global Precipitation Climatology Centre (GPCC) and TRMM product and the lowest spatial accuracy was observed in CPC following by UDel and PERSIANN-CCS products in northern Punjab

Summary

Introduction

Accurate and reliable estimates of global climate patterns are directly associated with the regional variation in precipitation [1]. There is a growing agreement that long term changes in precipitation could alter the ecological and hydrological processes [8] and underpin our knowledge of global and regional climate change [9]. These accurate and reliable precipitation records underpin our knowledge of regional and global climate change, as well as their possible impacts on water resources [10,11]

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