State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan, 430072, China.
State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin, China Institute of Water Resources and Hydropower Research, Beijing, 100038, China.
Environ Sci Pollut Res Int. 2021 Jul;28(27):36076-36091. doi: 10.1007/s11356-021-12771-7. Epub 2021 Mar 8.
Reference evapotranspiration (ET) is an important parameter for characterization of the hydrological cycle, and it is also important for agricultural, environmental, and other studies. In this study, by collecting the daily meteorological data of 31 base stations in high-altitude areas of Tibet for 35 consecutive years, the daily reference crop evapotranspiration (ET) of each base station is calculated by the ASCE Penman-Monteith formula. The Mann-Kendall method is applied primarily to test the trend of meteorological elements and ET. In addition, the software ArcGIS was used to generate spatial interpolation distribution maps of meteorological elements and ET so that the spatio-temporal variation trend of each base station is carried out. The ET in Shigatse shows an insignificant downward trend, while the other six regions show an upward trend, which is related to temperature and humidity directly with R of 0.23 and 0.67. The relative humidity (RH) and sunshine duration (SD) in Tibet show an overall three-step distribution in the east, middle, and west with RH decreasing from east to west and SD increasing from east to west. Annual cumulative ET of Ngari is the largest and decreases from west to east gradually, while ET increasing from east (lower elevation) to west (higher elevation) of Tibet with ranging from 730 to 1255 mm/year. This study not only is important for understanding of ET changes but also provides the preliminary and elementary reference for agricultural water management in Tibet with high elevation.
参考蒸散量（ET）是描述水文循环的重要参数，对农业、环境和其他研究也很重要。本研究通过收集西藏高海拔地区 31 个基准站 35 年的逐日气象数据，采用 ASCE Penman-Monteith 公式计算各基准站逐日参考作物蒸散量（ET）。采用 Mann-Kendall 方法检验气象要素和 ET 的变化趋势。此外，利用 ArcGIS 软件生成气象要素和 ET 的空间插值分布图，对各基准站的时空变化趋势进行分析。日喀则的 ET 呈不显著下降趋势，而其他六个地区呈上升趋势，这与温度和湿度直接相关，与 R 的相关性分别为 0.23 和 0.67。西藏的相对湿度（RH）和日照时数（SD）呈东、中、西三步式分布，RH 从东向西递减，SD 从东向西递增。阿里的年累计 ET 最大，从西向东逐渐减少，而西藏从东（低海拔）到西（高海拔）的 ET 呈增加趋势，年变化范围为 730-1255mm/年。本研究不仅有助于了解 ET 的变化，还为高海拔地区的农业用水管理提供了初步的参考。
