An experiential formula about the evapotranspiration of reference vegeration on northern slope of Great Hing'an Mountains

By the method of time series analysis, the evapotranspiration of reference vegetation in the small watersheds of continuous permafrost on the northern slope of Great Hing'an Mountains was approached. The results showed that the evapotranspiration of the reference vegetation, ET_o, had an obvious periodic fluctuation within a year, i.e., from relatively low at the beginning of the year to high before or after July, and declining to the lowest by the end of the year. The ET_o had significant correlations with net radiation (R_n) and daylight hours (N), and the formula ET_o = 0.260R_n - 0.036N + 0.422 was established, based on the two years meteorological data of Amur basin, which would benefit to the further studies on the eco-hydrological processes in the permafrost areas of northern Great Hing'an Mountains.