“蒸发悖论”在黑河流域的探讨

利用黑河流域12个气象站点1960-2010年的气象资料,运用FAO Penman-Monteith模型计算潜在蒸散量,采用旋转经验正交函数、Mann-Kendall检验等方法系统分析了过去51 a间潜在蒸散量及气温的变化趋势,重点对"蒸发悖论"在黑河流域的规律进行分析.结果表明:根据潜在蒸散量的旋转经验正交函数分区结果,黑河流域可以划分为4个子区."蒸发悖论"仅于1960-1993年存在于黑河流域河西走廊区(Ⅱ区、Ⅲ区);其它各区无"蒸发悖论".1994-2010年由于潜在蒸散量的显著上升,河西走廊区"蒸发悖论"消失.1993年是黑河流域潜在蒸散量变化趋势的一个转折点,1994-2010年黑河流域的潜在蒸散量表现为统计显著的上升趋势.风速的变化是影响黑河流域河西走廊区"蒸发悖论"出现和消失的重要因素.

Evaporation paradox in the Heihe River basin

In this paper, based on the data from 12 meteorological stations in the Heihe River basin from 1960 to 2010, firstly potential evapotranspiration was calculated by using FAO Penman-Monteith model and then the changing tendencies in potential evapotranspiration and air temperature were analyzed by using rotated empirical orthogonal function(REOF) clustering method and Mann-Kendall test. The existence of "evaporation paradox" was also discussed. The results indicate that according to the rotated empirical orthogonal function(REOF) clustering method, the Heihe River basin can be divided into four subareas. "Evaporation paradox" only existed in the Hexi Corridor region(areas Ⅱ and Ⅲ) from 1960 to 1993; due to a marked increase in potential evapotranspiration, "evaporation paradox" had disappeared from 1994 to 2010. From 1960 to 2010, no "evaporation paradox" phenomenon had existed in other subareas. 1993 was a turning point for the potential evapotranspiration tendency, after which potential evapotranspiration in the Heihe River basin showed a statistically significant upward tendency. Wind speed was an important factor that affects the appearance and disappearance of "evaporation paradox" in the Hexi Corridor region in the Heihe River basin.