Bias correction of precipitation data and its effects on aridity and drought assessment in China over 1961-2015

Ning Yao; Yi Li; Na Li; Daqing Yang; Olusola Olaitan Ayantobo

doi:10.1016/j.scitotenv.2018.05.243

Bias correction of precipitation data and its effects on aridity and drought assessment in China over 1961-2015

Sci Total Environ. 2018 Oct 15:639:1015-1027. doi: 10.1016/j.scitotenv.2018.05.243. Epub 2018 May 26.

Authors

Ning Yao¹, Yi Li², Na Li¹, Daqing Yang³, Olusola Olaitan Ayantobo⁴

Affiliations

¹ College of Water Resources and Architectural Engineering, Northwest Agriculture and Forestry University, Yangling, Shaanxi 712100, China; Institute of Water Saving Agriculture in Arid Areas of China, Northwest Agriculture and Forestry University, Yangling, Shaanxi 712100, China.
² College of Water Resources and Architectural Engineering, Northwest Agriculture and Forestry University, Yangling, Shaanxi 712100, China; Institute of Water Saving Agriculture in Arid Areas of China, Northwest Agriculture and Forestry University, Yangling, Shaanxi 712100, China. Electronic address: liyikitty@126.com.
³ Environment and Climate Change Canada, Saskatoon, SK S7N 3H5, Canada.
⁴ College of Water Resources and Architectural Engineering, Northwest Agriculture and Forestry University, Yangling, Shaanxi 712100, China.

PMID: 29929271
DOI: 10.1016/j.scitotenv.2018.05.243

Abstract

The accuracy of gauge-measured precipitation (P_m) affects drought assessment since drought severity changes due to precipitation bias correction. This research investigates how drought severity changes as the result of bias-corrected precipitation (P_c) using the Erinc's index I_m and standardized precipitation evapotranspiration index (SPEI). Daily and monthly P_c values at 552 sites in China were determined using daily P_m and wind speed and air temperature data over 1961-2015. P_c-based I_m values were generally larger than P_m-based I_m for most sub-regions in China. The increased P_c and P_c-based I_m values indicated wetter climate conditions than previously reported for China. After precipitation bias-correction, Climate types changed, e.g., 20 sites from severe-arid to arid, and 11 sites from arid to semi-arid. However, the changes in SPEI were not that obvious due to precipitation bias correction because the standardized index SPEI removed the effects of mean precipitation values. In conclusion, precipitation bias in different sub-regions of China changed the spatial and temporal characteristics of drought assessment.

Keywords: Bias-correction; Climate types; Decadal change; Droughts; Precipitation.