蒸散是水循环和能量循环的重要过程,也是连接土壤-植被-大气系统的关键纽带。气候变化背景下,蒸散的时空分布研究可为地区水资源合理配置及应对气候变化提供科学基础。本文基于结合GRACE(Gravity Recovery and Climate Experiment)数据的水量平衡方法模拟黄土高原汾沁地区20032015年蒸散量,并分析其不同时间尺度的变化特征,结果表明:①结合水储量变化的水量平衡方法与忽略水储量变化的水量平衡方法模拟所得蒸散相比,前者时间序列上波动更平稳(变异系数、标准差、极端值分别减少0.12,5.50mm,3.20%),可更精确地反映汾沁地区实际蒸散在年和季节尺度上的变化规律;②研究区20032015年均蒸散量为530.19mm,空间分布上由北向南大致增加,年际波动较平稳(变异系数为0.08),其中2010年蒸散量最低(478.22mm),2011年蒸散量最高(614.57mm);③季节尺度上,夏季平均蒸散量最高(263.36mm),占全年蒸散量的49.67%,波动较平稳;冬季蒸散量最低(19.50mm),离散程度较大;④汾沁地区20032015年蒸散变化主要受温度、降水的影响,其年际波动主要与降水相关。
英文摘要:
Evapotranspiration (ET) is a critical component in the surface energy budget as well as the water cycle.ET is also a key bond that connects the soil-vegetation-atmosphere system.With the climate change,studying the spatio-temporal distribution of ET has great implications in the reasonable allocation of regional water resources.This paper simulated the monthly ET based on water balance method using Gravity Recovery and Climate Experiment (GRACE) data in Fenqin Region from 2003 to 2015,and then analyzed its spatio-temporal dynamics in different time scales.It was found that the ET simulated by water balance method considering the water storage changes were more stable in the time series (the coefficient of variation,the standard variation,and the extreme values respectively reduced 0.12,5.50mm,3.20%),and more accurately in reflecting the temporal variations of annual and seasonal ET in Fenqin Region,comparing to the results simulated by water balance method neglecting the water storage changes.Average annual ET was 530.19mm in Fenqin Region from 2003 to 2015.There was a spatial distribution of increasing from north to south.Moreover,ET fluctuated quite smoothly during the study period with a lowest value in 2010 (478.22mm) and a highest value in 2011 (614.57mm),and the coefficient of variation was 0.08.At seasonal scale,ET was highest in summer (263.36mm) which accounted for 49.67% of annual ET and lowest in winter (19.50mm).Besides,the degree of dispersion was relatively higher in winter and lower in summer.The temporal variation of ET in Fenqin Region from 2003 to 2015 was mainly affected by precipitation and temperature,and the fluctuation of annual ET was mainly related to precipitation.