Analysis of temporal and spatial characteristics about surface actual Evapotranspiration in Haihe river basin based on MODIS

The MOD16 (MODIS Global Evapotranspiration Project) global evapotranspiration (ET)/latent heat flux (LE)/potential ET (PET)/potential LE (PLE) datasets are regular 1-km2 land surface ET datasets for the 109.03 Million km2 global vegetated land areas at 8-day, monthly and annual intervals. The dataset covers the time period 2000 through 2014. This project is part of NASA/EOS project to estimate global terrestrial evapotranspiration from earth land surface by using satellite remote sensing data. With the aid of MODIS ET products (MOD16), 15-year spatial-temporal data was obtained. Through the analysis of the ET mean and the slope of the trend line in month and year, the temporal change of ET in Haihe basin was found. At the same time, spatial change of the ET in the river basin influenced by different land use types and different DEM ranks was investigated. The results showed that: (1) Annual ET mean of Haihe River basin ranged from 186.35 mm to 858.60 mm. ET was relatively uniform in 2004 and 2006, and regional differences of ET is slight. (2)ET fluctuated slightly from 2000 to 2014, about ±10mm per year. Taking Datong-Baoding-Langfang-Tangshan line as a boundary, ET in south and north of it presented a different trend. 3) There are strong regularity in different land use and DEM ranks. 4) ET distribution was uniform between January to March and October to December, ET increased gradually from April to August, and spread from southeast to northwest of river basin, it reached the maximum in August.