Climate Change and Climate Variability

Oral Abstract

Spatiotemporal Variability of Reference Evapotranspiration and Contributing Climatic Factors in China During 1961-2013

Wednesday, January 4
10:30 AM - 12:30 PM
Location: 2nd & 3rd Meeting Room

Evapotranspiration is an active and complicated hydrological component linking water balance and land surface energy balance in the ecosystem. The reference evapotranspiration (ETo) for 4189 grid points in China from 1961 to 2013 was calculated in this study utilizing the FAO Penman-Monteith method (P-M) based on an updated high-resolution (0.5°×0.5°) gridded dataset. The spatiotemporal distribution of ETo was also analyzed utilizing the methods of Mann–Kendall trend test, multiple regression analysis, and wavelet analysis. Five climatic variables including wind speed (WS), sunlight duration (SD), relative humidity (RH), maximum daily temperature (Tm) and minimum daily temperature (Tn), were selected to identify the contribution to variability of ETo. The spatiotemporal evolution of each climatic variable was also investigated. Results indicate that ETo distribution in China differed significantly both in seasonal and spatial scale in general and both annual and seasonal ETo exhibited significant decreasing trends (P < 0.05).  A turning point occurred in 1982 for the temporal variability of ETo and the fluctuation periods of 2.4- and 3.4-years existed in the ETo series. The climatic variables of WS, SD and RH exhibited decreasing trends over the study period, while Tm and Tn increased significantly (P < 0.05). Multivariate regression analysis indicated ­that WS was the most influential climatic variable related to ETo variability, followed by Tm, SD, RH and Tn. Significant declines (P < 0.05) of WS and SD were indicated in the decrease of ETo while the increase of Tm and Tn and the decrease of RH contributed to enhancing ETo. Further study revealed that relative contributions of climatic variables to ETo were temporally unstable and varied considerably in China. Additionally, relative spatial distribution contribution of various climatic variables significantly differed: south and east China were dominated by SD, northeast China and Qinghai-Tibet Plateau were controlled by Tm while WS governed northwest China.

Wang Zhaoli

South China University of Technology

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Lai Chengguang

South China University of Technology

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Spatiotemporal Variability of Reference Evapotranspiration and Contributing Climatic Factors in China During 1961-2013



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