蒸发是流域水量平衡和能量平衡的重要组成部分，涉及到土壤、植被、大气等与气候密切相关的很多过程。潜在蒸发的准确计算在气候资源和水资源评价，土地管理和流域管理等方面具有重要意义。目前国际上已有很多基于不同原理得出的经验公式，这些公式在不同区域不同气象条件下的适宜性不尽相同。农业政策与环境拓展模型APEX（Agricultural Policy Environmental eXtender）是一种适用于田间和小流域尺度的水文/水质模型。虽然APEX模型目前已在美国等地得到了广泛验证和应用，但在东北地区的适应性研究尚属空白。本研究在东北地区不同气候区共选取7个代表气象站点，利用APEX模型中推荐的Penman、Penman-Monteith、Priestley-Taylor、Hargreaves和Baier-Robertson五种潜在蒸发的经验公式进行计算，并对结果在东北地区的适应性进行评价。在不同气候区、可获得的气象资料不同的条件下，推荐适宜的计算方法，并列出计算方法的系统偏差修正系数。结果表明：（1）东北地区E601型大型蒸发皿的观测数据转换为Φ20型小型蒸发皿观测数据的转换系数为1.624。（2）在平均气压、平均气温、最高气温、最低气温、平均相对湿度、平均风速、日照时数数据均可获得时，Penman公式的计算精度最优；在日照时数、风速等数据难以获取时，可以在相应区域选择Hargreaves和Baier-Robertson公式计算。（3）对于各公式的计算结果有必要进行修正以反映实际的潜在蒸发，各站的修正系数变化于0.4-0.86，修正后均方根误差RMSE均有较大幅度的减小。该研究结果可为进一步使用APEX模型在东北地区进行水文/水质评估提供支撑。

Evaporation is an important part of water balance and energy balance in a river basin, which involves soil, vegetation, atmosphere and many other processes closely related to climate. Accurate calculation of potential evaporation is of great importance in climate and water resource assessment, land management and watershed management. At present, there are many empirical formulas based on different principles in the world, and the suitability of these formulas is different in different regions and under different meteorological conditions. The Agricultural Policy Environmental Extender (APEX) is a hydrological/water quality model applicable at the field and small watershed scales. Although APEX model has been widely verified and applied in the United States and other places, the adaptability research in Northeast China is still a blank. In this study, seven representative meteorological stations were selected from different climatic regions in Northeast China. Five empirical formulae of potential evaporation, Penman, Penman-Monteith, Priestley-Taylor, Hargreaves and Baier-Robertson, which recommended by APEX model, were used for calculation, and the adaptability of the results in Northeast China was evaluated. Under the condition of different climatic area and different meteorological data, the appropriate calculation method is recommended, and the correction coefficient of system deviation of the calculation method is listed. The results show that :(1) The conversion coefficient of the observation data from E601 large pan to Φ20 small pan in Northeast China is 1.624.(2) The calculation accuracy of Penman formula is optimal when the data of average air pressure, average air temperature, maximum air temperature, minimum air temperature, average relative humidity, average wind speed and sunshine duration are all available ;Hargreaves and Baier-Robertson formulas can also be selected for calculation in the corresponding area when sunshine duration and wind speed are difficult to obtain.(3) It is necessary to revise the calculation results of each formula to reflect the actual potential evaporation, and the correction coefficients of each station vary from 0.4-0.86. After the correction, the root mean square error (RMSE) is greatly reduced. The results of this study can provide support for the application of APEX model in the evaluation of hydrology/water quality in Northeast China.