Explaining the evaporation paradox in Jiangxi Province of China: Spatial distribution and temporal trends in potential evapotranspiration of Jiangxi Province from 1961 to 2013

Xianghui Lu; Hua Bai; Xingmin Mu

摘要

Abstract Evaporation acts as an important component and a key control factor in land hydrological processes. In order to analyze the trend of change on potential evapotranspiration from 1961 to 2013 and to discuss the existence of the evaporation paradox in Jiangxi province, China, monthly meteorological data spanning the years 1961–2013 were analyzed in this study, where the data were collected from 15 national meteorological stations in Jiangxi Province. The Penman–Monteith equation was employed to compute the potential evapotranspiration ( ET ₀). Spatial interpolation and data mining technology were used to analyze the spatial and temporal changes of ET ₀ and air temperature, with the effort to explain the evaporation paradox. By solving the total differential and the partial derivatives coefficients of the independent variables in Penman–Monteith equation, the cause of the paradox was quantitatively evaluated. The results showed that the annual ET ₀ had been decreasing significantly in Jiangxi Province since 1979, whereas the air temperature had been rising significantly, presenting the evaporation paradox. The decreases in sunshine duration and wind speed reduced ET ₀ by 0.207?mm and 0.060?mm, respectively, accounting for 92.3% and 26.7% of the total ET ₀, respectively. It is concluded that sunshine duration and wind speed are the main causes to the decrease in potential evapotranspiration in Jiangxi Province. Keywords Jiangxi province ; Evaporation paradox ; Penman–Monteith model ; Spatial and temporal variation prs.rt("abs_end"); 1. Introduction Evapotranspiration is an important component of hydrologic cycling processes and the energy flow ( Chahine, 1992 ). Abnormal evaporation acting on underlying surfaces is likely to cause extreme hydrological events ( Trenberth, 1999 ). Existing research shows that the temperature throughout China has increased by (0.09±0.017)?°C/10a throughout the years 1960–2006 ( Li et al., 2010 ). It is deduced that temperature rise tends to increase both evaporation capacity and evaporation amount. However, contradictory to the deduction, ET ₀ and pan evaporation throughout China displayed trends of significant decrease ( P 2. Materials and methods 2.1. Outline of the area investigated Jiangxi Province is located in the red earth hilly area of South China ( Fig. 1 ). The climate is subtropical monsoon-type climate with wet summer and dry autumn. An annual average temperature of 11.6–19.6?°C and an annual precipitation of 1637.9?mm, sufficient total water resources and many projects on water conservation ( Sun, Zhang, Chen, & Chen (2010a) and Zheng, Fang, Yang, Xie, & Chen (2012) ). However, seasonal drought occurred frequently in recent years and the first drought warning was released in 2011 ( Wu, 2011 ). The precipitation was gradually decreases at the end of the main flood season in summer and autumn, during which evaporation becomes the controlling factor of moisture movement. Throughout one year, the geographical distribution of precipitation does not match the heat distribution. The precipitation decreases after the main flood season. The local soil is red earth which has poor performance in water conservation. The soil moisture is controlled by evaporation. This leads to considerable chance of seasonal drought occurrence. Fig. 1.?Location of the Jiangxi province of China. It is on the southern bank of the Yangtze River, between 24°29′–30°04′ north latitude and 113°34′–118°28′ east longitude, covering a total area of 166,900?km2. Figure options Download full-size image Download as PowerPoint slide 2.2. Study methods In this study, the monthly meteorological data of 1961–2013 recorded at 15 national meteorological stations (see Fig. 2 for the distribution of the stations) in Jiangxi Province were provided by the China Meteorological Science Data Sharing Service Network. The Penman–Monteith equation ( Monteith, 1963 ) was used to compute ET ₀ and the Thiessen polygon method was employed to compute ET ₀ of Jiangxi Province. Kriging interpolation, linear regression and the Pettitt method were adopted to analyze the spatial distribution, trend and mutation of ET ₀. The Penman–Monteith equation was solved for the partial derivatives of the independent variables. The total differential and the partial derivative coefficients of the independent variables were used to quantitatively evaluate the cause of ET ₀ changes and the sensitivity ET ₀ to the independent variables.

机译：摘要蒸发是陆地水文过程的重要组成部分和关键控制因素。为了分析1961年至2013年潜在蒸散量的变化趋势，并探讨中国江西省蒸发量悖论的存在，本研究分析了1961年至2013年的月度气象数据，并收集了这些数据。来自江西省的15个国家气象站。 Penman–Monteith方程用于计算潜在的蒸散量（ET _{0 ）。利用空间插值和数据挖掘技术分析了ET _{0 和气温的时空变化，试图解释蒸发的悖论。通过求解Penman–Monteith方程中自变量的总微分和偏导数系数，定量地评估了产生这种悖论的原因。结果表明，自1979年以来，江西省的年ET _{0 显着下降，而气温却显着上升，呈现出蒸发悖论。日照持续时间和风速的减少使ET _{0 分别减少了0.207？mm和0.060？mm，分别占ET _{0 总量的92.3％和26.7％。。结论是，日照持续时间和风速是造成江西省潜在蒸散量下降的主要原因。关键词江西省;蒸发悖论; Penman–Monteith模型;时空变化prs.rt（“ abs_end”）; 1.引言蒸散量是水文循环过程和能量流的重要组成部分（Chahine，1992）。作用在下层表面的异常蒸发很可能引起极端的水文事件（Trenberth，1999）。现有研究表明，从1960年至2006年，中国的温度升高了（0.09±0.017）？°C / 10a（Li等，2010）。可以推断，温度升高趋于增加蒸发能力和蒸发量。然而，与推论相反，整个中国的ET _{0 和蒸发皿蒸发量显示出显着下降的趋势（P 2.材料和方法2.1。调查区域的轮廓江西省位于红壤丘陵区华南地区（图1），气候属亚热带季风型气候，夏季湿润，秋季干燥，年平均气温11.6-19.6？C，年降水量1637.9？mm，总水资源充足，水资源保护项目（孙，张，陈和陈（2010a）和郑，方，杨，谢和陈（2012）），但近年来季节性干旱频繁发生，2011年发布了第一份干旱预警（Wu，2011）。在夏季和秋季的主要汛期末，降水量逐渐减少，在此期间，蒸发成为水分运动的控制因素，而在整个一年中，降水的地理分布都与降水量不符。在分发。在主汛期之后，降水量减少。当地的土壤是红土，其节水性能较差。土壤水分通过蒸发来控制。这导致季节性干旱发生的可能性很大。图1.中国江西省的位置。它位于长江南岸，北纬24°29′–30°04′至东经113°34′–118°28′之间，总面积166,900？km 2 。图选项下载完整尺寸的图像下载为PowerPoint幻灯片2.2。研究方法在这项研究中，由中国气象科学数据共享服务网络提供了江西省15个国家气象站的1961-2013年每月气象数据（气象站的分布见图2）。利用Penman–Monteith方程（Monteith，1963年）计算ET _{0 ，并采用Thiessen多边形法计算江西省的ET _{0 。采用Kriging插值法，线性回归法和Pettitt法分析ET _{0 的空间分布，趋势和变异。对于自变量的偏导数，求解了Penman-Monteith方程。使用自变量的总微分和偏导数来定量评估ET _{0 变化的原因和ET _{0 对自变量的敏感性。}}}}}}}}}}}

Explaining the evaporation paradox in Jiangxi Province of China: Spatial distribution and temporal trends in potential evapotranspiration of Jiangxi Province from 1961 to 2013

摘要

著录项

相似文献

相关主题

期刊订阅