Estimating Daily Actual Evapotranspiration using Remotely Sensed Data over East Asia Region

Evapotranspiration (ET) which is a latent heat flux including water evaporation from surfaces and vegetation transpiration is an important component of the global hydrological cycle. The National Institute of Meteorological Research at Korea Meteorological Administration (KMA/NIMR) developed an algorithm of daily ET (NIMR ET) with the Communication, Ocean and Meteorological Satellite (COMS) over East Asia region (100.00°E ~145.00°E, 20.00°~50.00°N) in 2012 for climate monitoring. The COMS geostationary-orbiting satellite was launched on 27 June 2010, observes northern hemisphere with 5 spectral bands (visible channel: 1 km, Infrared channel: 4 km) for northern hemisphere, and provides several products of land and atmosphere. The COMS products such as brightness temperature, land surface temperature, and NDVI are utilized for the ET algorithm of NIMR. ET algorithm of NIMR is based on surface energy balance, using simplified sensible heat flux [H] and net radiation flux [Rn]. The NIMR ET is 1-day composite data with spatial resolution of 1 km on cloud-free days except for urban and desert area. And, the ET algorithm has reflected the vegetation canopy height and surface characteristic over the East Asia region. NINR ET was compared with flux tower measurements at four validation sites in East Asia region. Validation results show 2.667 mm/day of RMSE and 1.998 mm/day of Bias. The NIMR ET has the regional and seasonal variability as growing-season maximum values and decline-season minimum values. And, the NIMR ET shows as dynamic changes in cropland and forest. The detailed results will be presented at the conference.