Surface Water Hydrology

Poster Abstract

Research on Et Temporal and Spatial Pattern Changed with Crop Plant Structure by Temporal Up-scaling of Remote Sensing Et Model at Irrigation District Level

Wednesday, January 4
10:00 AM - 5:00 PM
Location: ChuLv Hall

Remote sensing (RS) has been considered as the most promising tool for evapotranspiration (ET) estimation at regional scale. However, large errors implied in the process of extrapolating instantaneous latent heat flux derived at satellite over-passing time to daily ET inevitably constrains the application of RS models. In this study, we chose Jiefangzha Irrigation field in Hetao irrigation district as typical study area, the study established single layer remote sensing ET model base on energy balance theory. By using MODIS standard land products on-boarded Terra and Aqua satellites in 2014, the study discussed temporal up-scaling method from instantaneous level at satellite over-passing time to daily level and from daily level which contaminated by clouds to continuous yearly level separately. Daily representative parameter method was used to up-scale the instantaneous ET to daily ET, which reduced the error in the processes of meteorological data downscale and ET up-scale; while interpolation based on pixel unit was used to up-scale daily ET at clear days to continuous ET, which maximum the usage of available remote sensing data. One merit of the improved model is that the calculation of daily ET can be avoided by means of instantaneous input from ground observations is avoided, which is insufficient at regional scale from meteorological stations. The second merit is the model circumvents the scaling up process implied in the traditional methods. Another merit is that the cloud-free constrain of ET estimation based on RS data is circumvented through a gap filling approach, which makes continuous ET estimation possible. We did a five-year continuous simulation from 2011 to 2015 in Jiefangzha Irrigation field, and then discuss the pattern of temporal and special change by means of plant structure.

He Chen

China Institute of Water Resources and Hydraulic Research

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Liangliang Bai

China Institute of Water Resources and Hydraulic Research

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Jiabing Cai

China Institute of Water Resources and Hydraulic Research

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Baozhong Zhang

China Institute of Water Resources and Hydraulic Research

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