Journal of Global Ecology and Environment
 

Journal of Global Ecology and Environment, ISSN No. : 2454-2644, Vol.: 7, Issue.: 1

Original Research Article

LINEAR MULTI-REGRESION MODEL FOR ESTIMATING ACTUAL DAILY EVAPOTRANSPIRATION BASED ON S-SEBI METHOD OVER CAU RIVER BASIN OF VIETNAM USING LANDSAT-7 IMAGES

 

NGUYEN VAN HUNG1*, LUONG CHINH KE2 AND LE THI HAI NHU3

1Department of National Remote Sensing, Hanoi, Vietnam.

2Vietnam Association of Surveying - Mapping – Remote Sensing, Hanoi, Vietnam.

3Departement of Survey, Mapping and Geographic Information, Vietnam.

Abstracts

Calculating the actual evapotranspiration (ETa) is an important task in monitoring water balance in river basins, serving irrigation management in agriculture and in weather forecasting. In fact, it is difficult to measure ETa directly and most ETa applications are calculated using empirical-theoretical models. This paper proposes a linear multi-regression model to calculate ETa based on the relationship between ETa extracted by the Simple Surface Energy Balance Index (S-SEBI) with the surface biological-physical parameters, such as albedo, normal difference vegetation index (NDVI), surface temperature (Ts), and net surface solar radiation (Rnd) that were extracted from the Landsat-7 imagery dated November 23, 2001. The proposed model was evaluated based on ETa field observations on meteorological stations on November 4th, 2000 with Root Mean Square Error (RMSE) of 1.585 mm/day and Mean Absolute Error (RAE) of 35.44%. After eliminating the Mean Bias Error (MBE) the model achieves accuracy with RMSE = 0.702 mm/day and MAE = 17% (model accuracy is 83%).

Keywords :

Actual evapotranspiration; albedo; normal difference vegetation index NDVI; surface temperature; solar radiation.