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| DOI：10.13522/j.cnki.ggps.2019394 |
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| Temporal and Spatial Variations of Reference Crop Evapotranspiration and Its Influencing Factors in Jiangsu Province |
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WANG Meng1, 2, 3, LIU Chunwei1, 2, 3*, QIU Rangjian1, 2, 3，ZHANG Pei1, 2, 3,ZHANG Fangmin1, 2, 3
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1.Jiangsu Key Laboratory of Agricultural Meteorology, Nanjing 210044, China; 2.Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disaster, Nanjing 210044, China; 3. School of Applied Meteorology, Nanjing University of Information Science &Technology, Nanjing 210044, China; 4. Jiangsu Meteorological Bureau, Nanjing 210044, China
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| Abstract: |
| 【Objective】 The evapotranspiration of reference crops is an important part of water cycle and energy cycle. The study of its variation characteristics and influencing factors can provide reference for rational utilization of water resources, efficient water management and agricultural production layout in this area. 【Method】This study calculated the daily evapotranspiration (ET0) by using the data of wind speed, temperature, relative humidity and sunshine hours from 1961 to 2018 of 60 locations in Jiangsu province. ,and using methods of climate trend rate, sensitivity analysis, Kriging space interpolation and contribution rate analysis, the present paper analyzed the temporal and spatial variations and the influencing factors of ET0 in Jiangsu. 【Result】①Rhe mean ET0 was 976.8 mm and the change of the whole area ET0 was -0.439 mm/10 a from 1961 to 2018 in Jiangsu province. 28 of the locations (47%), mainly located in Wuxi and Suzhou, showed an increasing trend of ET0. There were significant increases of ET0 in 11 sites, among which the climate tendency rates in Wuxi, Taicang and Jingjiang area were 18.58 mm/10 a,18.97 mm/10 a, 29.65 mm/10 a, respectively. 32 of the locations (53%), mainly distributed in Lianyungang, Xuzhou, Suqian, presented a decreasing trend of ET0 with a significant decreasing trend (p<0.05) in 16 sites. As characteristic areas, the climate tendency rates The climate tendency rates in Xinyi, Sihong and Guannan decreased by -19.22 mm/10 a, -23.07 mm/10 a, -23.15 mm/10 a, respectively. ②Fengxian county (1 007.4 mm), Xuzhou (1 041.1mm) and Xilian island (1 130.3mm) are the high value centers of ET0; ③ET0 is sensitive to average temperature, sunshine hours, wind speed and relative humidity. The decision coefficients of average temperature, sunshine hours, wind speed, relative humidity and ET0 are 0.09, 0.33, - 0.02 and 0.29 respectively. And ET0 is the most sensitive to relative humidity with a negative correlation coefficient of -0.516 (p<0.01). The zonal distribution characteristics of ST and SWS are obvious in the spatial distribution of sensitivity coefficient. ④The analysis of contribution rate indicated that wind speed and relative humidity had a great contribution to the change of ET0. There were 22 locations, evenly distributed in the north Jiangsu province, mainly influenced by wind speed. Among them, the wind speed of Peixian, Siyang and Xinyi contributed greatly to the change of ET0 with values of -13.44%, -12.52%, -12.49%, respectively. And 38 sites, mainly located in the south areas, were mainly influenced by the relative humidity. As characteristic areas, Danyang, Jingjiang and Kunshan contributed greatly to the change of ET0 with values of 18.47%, 18.57%, 20.87%, respectively. In addition, the average temperature and sunshine hours in the whole region have no main effect on the change of ET0. 【Conclusion】The main influencing factor of ET0 change in Northern Jiangsu is wind speed, and the contribution rate of wind speed is negative. The main influencing factor of ET0 change in southern Jiangsu is relative humidity, and the contribution rate of relative humidity is positive. |
| Key words: reference crop evapotranspiration; sensitivity analysis; contribution rate analysis; Jiangsu Province |
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