Abstract: Evaporation (ET₀ ) is an important part of the hydrological cycle. A detailed analysis of the relationship between ET₀ and meteorological factors is of great significance for water resources, ecological restoration and reconstruction, and sustainable development of social and economic in China’s important ecological transition zone. In this paper, based on the data from 70 meteorological stations in the south and north of Qinling Mountains during 1970—2017, potential evaporation was first calculated using FAO (Food and Agriculture Organization of the United Nations) Penman- Monteith model. Moreover, variation of temperature and ET₀ in the south and north of Qinling Mountains is analyzed and the relationship between ET₀  and meteorological factors i.e., temperature, wind speed, sunshine duration, relative humidity are investigated to determine which factor primarily influences ET₀  using a sliding correlation coefficient and wavelet coherence. The results are as follow: based on the mutual correspondence of trends, there is uncertainty in the response relationship between ET₀  and temperature in the south and north of Qinling Mountains. It is not a simple reverse correspondence, that is, the higher the temperature, the more the evaporation. Based on the sliding correlation coefficient, whether we adjusted the size of sliding correlation window or divided the different time periods, there is always a significant positive correlation between ET₀  and temperature, implying that the existence of“evaporation paradox”phenomenon in the study region could not be detected. However, there is a spatiotemporal difference in the correlation between the temperature and ET₀ in the south and north of Qinling Mountains. In terms of the relationship between temperature and evaporation, 1993 was a turning change point since the correlation in the whole period increased initially and then decreased. In terms of spatial variation, regardless of the sequence (original or detrending) and sliding correlation window (11 a or 21 a), the correlation pattern of temperature and ET₀  in the south and north of Qinling Mountains has not changed much, while a weak correlation is observed in the western part of Qinling Mountains. For the influence of meteorological factors change on ET₀  change, it is well established that with the observed decreased sunshine duration and wind speed and increased relative humidity, the ET₀  has been decreasing over the past 48 a, which confirmed three existing assumptions: (1) the reductions in sunshine duration is the first factor for the decline in ET₀  resulting from the evidences in three sub- regions in the south and north of Qinling Mountains, (2) the decreasing wind speed is the second factor for the decline in both northern and south piedmont of Qinling Mountains, and (3) the increasing change in relative humidity exacerbated the decrease of ET₀  in Hanjiang River Basin. However, temperature is the last related factor to ET₀  in south and north of Qinling Mountains. The interaction of multiple factors may influence the variation of ET₀  rate, which is the main reason for the complexity of the‘evaporation paradox’in south and north of Qinling Mountains.

Key words: climate change, potential evaporation, evaporation paradox, trend analysis, the south and north of Qinling Mountains