西南地區不同高程蒸散發陰陽坡分異特征

摘" 要：山地隆起引發的山體效應可以改變區域的水熱條件，坡向調節入射太陽輻射，影響蒸散發的分布。該文以中國西南地區為研究區，利用多年蒸散發和氣候數據，探索不同高程上陰坡和陽坡的蒸散發時空分布、變化特征及影響因素。結果表明，蒸散發量隨著高程的遞增而減少。在4 500 m以下，陰坡的蒸散發量多小于陽坡，但在4 500 m以上，存在陰坡的蒸散發量更大的情況；植被覆蓋度、太陽輻射對陰坡和陽坡的蒸散發都有正向影響，而土壤水分和相對濕度為負向影響。造成不同高度陰坡和陽坡蒸散發差異的主要因素為氣溫、水分限制以及地表溫度與空氣溫度的差值。

關鍵詞：蒸散發；西南地區；不同高程；陰陽坡；影響因素

中圖分類號：TP79" " " 文獻標志碼：A" " " " " 文章編號：2095-2945（2024）33-0095-04

Abstract： The uplift-induced topographic effects can alter the water and heat conditions of the regional， slope orientation can regulate the incident solar radiation， and influence the distribution of evaporation. In this study， the evaporation and climate data from the southwestern region of China were used to explore the spatial and temporal distribution and change characteristics of evaporation on the shady and sunny slopes at different elevations， as well as the influencing factors. The results show that： The evaporation decreases with the increase of elevation. Below 4 500 m， the evaporation on the shady slopes is generally less than that on the sunny slopes， but there are cases where the evaporation on the shady slopes is greater than that on the sunny slopes above 4 500 m. The vegetation coverage， solar radiation have a positive impact on the evaporation on both the shady and sunny slopes， while the soil moisture and relative humidity have a negative impact. The main factor causing the difference in evaporation between the shady and sunny slopes at different elevations is the temperature， water limitation， and the difference between the surface temperature and air temperature.

Keywords： evapotranspiration; southwest region; different elevations; sunny and shady slope; influence factor

蒸散發是地表土壤、植被或水面中蘊含的水分從液態轉化為氣態的物理過程，它是地表水循環的重要組成部分[1]。蒸散發過程伴隨著能量的轉化，是地表能量平衡中的重要變量[2]。正是由于蒸散發在水文和能量等方面的特性，使其對全球生態系統和氣候變化產生了深遠影響，它作為重要的氣象要素，能對全球自然變化做出響應[3]。

山地隆起引發的山體效應可以改變區域的水熱條件，對蒸散發造成影響，進而影響生態地理氣候格局[4-5]。除了高程，坡向對蒸散發也有一定的作用。坡向調節入射太陽輻射，進而改變能量通量與大氣和地表之間的水，創造了具有不同近地表的獨特局部小氣候，可能使得蒸散發趨勢偏離整體區域的變化趨勢。……