黔中地区潜在蒸散发的时空变化及对土地利用变化的响应

Spatio-temporal variation of potential evapotranspiration and its response to land use change in central Guizhou

土地利用变化对潜在蒸散发的影响是水文等相关领域研究的热点问题。基于黔中地区1995-2015年气象数据,应用Penman-Monteith公式估算潜在蒸散发(ET 0),同时利用1995-2015年5期土地利用数据,分析近20年该地区ET 0的时空变化特征以及不同土地利用类型对ET 0的影响。结果表明:1995-2015年黔中地区ET 0总体呈增大趋势,空间分布规律较为明显,即自东南向西北整体呈递减趋势;黔中地区近20年土地利用结构变化明显,林地及建设用地面积的变化趋势以增大为主,草地及耕地则以减少趋势为主;不同土地利用类型的ET 0不同,以林地为最大,其次为耕地、草地、水域以及建设用地,未利用地为最小,草地以及耕地向林地转移面积会使ET 0增大,林地、草地以及耕地向建设用地、未利用地转移面积会使ET 0减小。这表明土地利用变化明显时,ET 0也会随着产生较大的变化。蒸散发研究对反映区域水文过程以及科学管理水资源均十分重要。

The impact of land use change on potential evapotranspiration is a hot issue in hydrology and other related fields.Based on the meteorological data of central Guizhou Province from 1995 to 2015,we estimated the potential evapotranspiration(ET 0)using Penman-Monteith equation and analyzed the spatio-temporal characteristics of ET 0 in this region and the impact of different land use types on ET 0 using the land use data from 1995 to 2015.The results show that the ET 0 of central Guizhou from 1995 to 2015 showed an overall upward trend,with a significant spatial distribution pattern,it decreased from southeast to northwest.The land use structure in central Guizhou changed significantly over the period of 1995-2015,the woodland and construction land were mainly increasing,whereas the grassland and cultivated land are mainly decreasing.Different land use types had different ET 0,with the ET 0 of woodland being the largest,followed by that of cultivated land,grassland,water area and construction land,and unused land had the smallest ET 0.The ET 0 increased when parts of the grassland and cultivated land were transferred to woodland,but it decreased when parts of woodland,grassland and cultivated land were transferred to construction land and unused land.This indicates that ET 0 changes simultaneously with the change of land use.This study on evapotranspiration can shed some light on the understanding of regional hydrological process and water resources management.