Spatiotemporal variation in rice evapotranspiration under the influence of rice expansion: a case study in the Sanjiang Plain, Northeast China

Studying the variation of rice evapotranspiration (ET) is essential for the management of water consumption in agriculture. In this paper, the Surface Energy Balance Algorithms for Land (SEBAL) and MODIS products were employed to estimate long-term rice ET from 2003 to 2018 in the Sanjiang Plain, Northeast China. The investigation further explored the spatiotemporal distribution of rice ET and its associated influencing factors. The research findings indicated that the SEBAL model accurately estimated the daily ET on the Sanjiang Plain. Rice ET in the Sanjiang Plain increased at a rate of 5.05 mm year-1. The spatial distribution of rice ET demonstrated significant variations across different typical years. Temperature was the main factor affecting rice ET on the Sanjiang Plain, with a correlation coefficient of 0.67. The increase in rice ET per ha was positively correlated with rice area expansion, with a correlation coefficient of 0.79. The growth rate of rice ET slowed after 2011, which was related to the cooling effect of irrigation due to rice area expansion.