Quantitative estimation of evapotranspiration from Tahe forest ecosystem, Northeast China. Spatial and temporal distribution of water requirement of cotton in Xinjiang from 1963 to 2012 AnevaluationoftheHargreavesmethodforestimatingreferenceevapotranspirationindifferentgrasslandtypesinInnerMongolia,China Trends in reference crop evapotranspiration and possible climatic factors in the North China Plain