1960-2017年艾比湖流域实际蒸散量与气象要素的变化特征

传统估算蒸散发的方法大都基于局地尺度,而在生态水文发生剧烈变化的资料稀缺流域背景下,充分考虑流域下垫面的空间变异性的陆面过程模型为流域长时序、大尺度及连续模拟实际蒸散量提供了新途径.以艾比湖流域为研究区,应用可变下渗能力模型(VIC)模拟1960-2017年艾比湖流域的水文过程,探讨研究区值实际蒸散发量的年、月、日时空...

Variation characteristics of actual evapotranspiration and meteorological elements in the Ebinur Lake basin from 1960 to 2017

Traditional methods for estimating evapotranspiration are mostly based on local scales. For data-scarce basins where ecological hydrology has undergone dramatic changes, a land surface process model that fully considers the spatial variability of the underlying surface of the watershed provides a new method of performing continuous actual evapotranspiration simulations over a long time series and at a large scale. Taking the Ebinur Lake basin as the research area, the variable infiltration capacity (VIC-3L) model was used to simulate the hydrological processes from 1960 to 2017 and explore the spatial and temporal variations in actual evapotranspiration in the study area. Additionally, the wavelet analysis method was used to analyze the multiscale characteristics of the five meteorological elements and the simulated values of actual evapotranspiration in the study area. The following results were obtained: (1) The runoff Nash-Sutcliffe efficiency (NSE) coefficients of the VIC at the Wenquan and Bole stations were 0.09 and 0.23, respectively, and the simulation results were satisfactory. Specifically, the simulated value and theoretical calculated value of the actual evapotranspiration of the VIC had an R² value of 0.80, an RMSE of 31.76 mm a^-1, an NSE of 0.32, and a relatively good simulation effect. (2) Regarding the time scale, the interannual actual evapotranspiration has presented an upward trend over the past 58 years, with the annual average actual evapotranspiration increasing at a rate of 1.03 mm a^-1. Furthermore, both monthly and daily evapotranspiration showed a single peak trend. Regarding the interdecadal changes, the actual evapotranspiration from May to July showed a downward trend in the 1990s and in the early 21st century, and an upward trend in the 1970s, while no significant change in tother months. (3) In terms of spatial distribution, the actual evapotranspiration generally showed strong evapotranspiration in high altitude areas and their surroundings. From spring to summer, the area with strong evapotranspiration shifted from the northwest to southeast. The spatial distribution of annual actual evapotranspiration is consistent with that in spring and summer. (4) A wavelet analysis identified 1 to 4 significant periods in the time-frequency domain for the actual evapotranspiration and meteorological elements in the study basin. Over a certain period, the average wind speed, average temperature, and sunshine hours changed ahead of the actual evapotranspiration while the annual precipitation and relative temperature lagged behind the actual evapotranspiration changes. Affected by precipitation, the actual evapotranspiration had a "strong-weak" transition in 1965 and 2003 with a period of 1 a; and affected by relative humidity, the actual evapotranspiration had a "strong-weak" transition in 1965 and 2008 with a period of 2-4.5 a.