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Arid Land Geography ›› 2024, Vol. 47 ›› Issue (7): 1136-1146.doi: 10.12118/j.issn.1000-6060.2023.559

• Climatology and Hydrology • Previous Articles     Next Articles

Fused-downscaling framework and spatiotemporal characteristics of TRMM 3B43 precipitation product in the Qinghai region

WANG Peng(), SHI Yuli()   

  1. Technology Innovation Center for Integrated Applications in Remote Sensing and Navigation, MNR, School of Remote Sensing and Geomatics Engineering, Nanjing University of Information Science and Technology, Nanjing 210044, Jiangsu, China
  • Received:2023-10-10 Revised:2024-03-24 Online:2024-07-25 Published:2024-07-30
  • Contact: SHI Yuli E-mail:wangpenghuainan@163.com;001986@nuist.edu.cn

Abstract:

Satellite remote sensing precipitation products have been widely used to estimate precipitation, especially in regions with sparse ground observation stations. However, the lower spatial resolution of these satellite products limits their application in localized regions and watersheds. This study proposes a fused downscaling framework based on the area-to-point kriging (ATPOK) algorithm and geographic weighted regression kriging (GWRK) algorithm to downscale TRMM 3B43 data for the Qinghai region of China from 2000 to 2019. The framework incorporates ground observation station data, normalized difference vegetation index (NDVI), digital elevation model, slope, and auxiliary factors for calibration, ultimately obtaining precipitation products at 1 km resolution. The results showed that: (1) The proposed fused downscaling framework can effectively improve the accuracy of TRMM 3B43 products; however, it cannot eliminate the overestimation of TRMM 3B43. (2) Compared to the ATPOK algorithm, the GWRK algorithm using data TRMM precipitation data and auxiliary factors can better estimate annual/monthly precipitation data. (3) Based on the study of the relationship between TRMM 3B43 and NDVI, it was found that NDVI responds to precipitation with a delay of 0-2 months. (4) Based on the spatiotemporal variation analysis of downscaled precipitation products, significant increases in monthly precipitation were observed in the Qinghai region, with an interannual change rate of 3.33% in dry month (December) and 1.79% in wet month (July).

Key words: spatial downscaling, TRMM 3B43, ATPOK, GWRK, downscaling-integration framework