摘要
基于MOD16遥感产品,在数据精度验证的基础上,运用GIS统计法、线性趋势法等研究了2000~2014年汉江流域蒸散发的年际和年内变化规律及不同土地覆被类型下的蒸散发特征。结果表明:1 2000~2014年,潜在蒸散发(PET)多年平均值为1 476 mm,呈东南向西北递减态势;实际蒸散发(ET)多年平均值约654 mm,ET呈东低西高,南高北低态势。不同土地覆被类型下年均PET和ET大小顺序相反。2 PET年际变化率为13.63 mm/a,呈弱增加趋势;ET年际变化率为-2.3 mm/a,呈弱减少趋势,表明汉江流域水资源呈减少趋势。PET空间上呈东增西减趋势,ET呈东减西增趋势,东北部具有干旱化倾向。3年内PET和ET呈单峰型。PET在6月最大,ET在7月最大,二者均在12月最小。二者在4~6月差距最大,形成春旱。不同土地覆被类型下PET和ET呈单峰型,植被生长季节ET差距大,林地增长速度最快。4 PET和ET具有较强的季节性。ET季节性空间差异非常显著,在于林地的植被蒸腾作用对全年ET贡献较大。流域西部山地ET季际增加趋势明显而东部呈减少趋势,整体上冬季年际变化最明显,春季最弱。
Based on MOD 16 products from remote sensing and its precision verification, this article analyzed the spatiotemporal characteristics of interannual and annual evapotranspiration and variation characteristics of evapotranspiration under different land cover types from 2000 to 2014, using statistical analysis of GIS, linear trend method and variation coefficient method et al. The results showed as follows： 1） In 2000-2014, the 15-year averaged PET was 1 476 mm and the spatial distribution of PET was decreasing trend from southeast to northwest while the 15-year averaged ET was 654 mm and the spatial distribution of ET in the west and south was higher than in the east and north. The averaged PET and ET are in the opposite order under different land cover types. 2） The interannual variability of PET was 13.63 mm/a and showed a weak increasing trend while ET was -2.3 mm/a and showed a weak decreasing trend. The gap of PET and ET showed an increasing trend, which indicated that water resources in the Hanjiang River Basin was decreasing. Spatial variation trend of PET was ＂the increasing in the East and the decreasing in the West＂ while ET was ＂the decreasing in the East and the increasing in the West＂. There was the tendency of drought in the northeast. 3） Interannual PET and ET was a single peak. PET was the largest in June and ET was the largest in July. Both of them were the smallest in December. The maximum gap between PET and ET was the spring drought from April to June. Monthly averages of PET and ET showed a single peak type under different land cover types. The difference of monthly ET for different land cover types was obvious in the vegetation growing season when monthly ET in forestland was the fastest growth rate. 4） Seasonal averages of PET and ET had obvious differences among the four seasons. Spatial distribution of seasonal ET was very significant which greatly attributed to the transpi- ration of forestland because it was greatest contribution to the annual ET. In 2000-2014, spatial change of sea- sonal ET was significantly increasing in mountainous western region of the Hanjiang River Basin, while de- creasing in eastern region. On the whole, the annual change of seasonal ET was the most obvious in winter, and the weakest in spring.
出处
《地理科学》
CSSCI
CSCD
北大核心
2017年第2期274-282,共9页
Scientia Geographica Sinica
基金
国家自然科学基金项目(41371523)
教育部人文社会科学重点研究基地项目(14JJD840004)资助~~
关键词
蒸散发
MOD16
土地覆被类型
汉江流域
evapotranspiration
MOD 16
land cover type
the Hanjiang River Basin
