Abstract: The interaction between wetland and atmosphere through the exchange of energy and mass forms unique regional microclimate characteristics.A comparative analysis of microclimate characteristics near the surface layer from 0 to 30 cm between Panjin reed wetland in the Liaohe River Delta and Jinzhou maize dry land located at the same latitude as at Panjin reed wetland was conducted in 2015 using the microclimate gradient method.The results show that the mean annual air temperature of Panjin wetland is 9.91℃ in 2015,which is 0.58℃ lower than that of Jinzhou maize dry land.The wetland plays a cooling effect in spring,summer and autumn,and a warming effect in winter.The daily variations of mean annual air temperature at Panjin wetland and Jinzhou maize dry land range from 7.50-12.92℃and 6.16-15.59℃,respectively.The amplitude of the mean temperature and temperature difference between the different vertical layers of the wetland are less than those of the dry land.The mean annual relative humidity at Panjin wetland is 64.58%,which is 7.97% higher than that of Jinzhou dry land.The monthly relative humidity of wetland is mainly affected by the hydrological factors and vegetation transpiration.The daily variations of mean annual relative humidity of wetland and dry land range from 51.78%-74.38% and 41.00%-73.00%, respectively.There are inversion humidity phenomena in both of wetland and dry land,while the occurring heights are different.The spring wind speed in Panjin wetland is 2 times higher than that in Jinzhou dry land.The wind speed of wetland increases exponentially with the height.During the growth season,Panjin reed wetland has a higher roughness.With the decrease of height,the wind speed decreases significantly.This kind of sheltering effect in wetland is much better than that in dry land.The land surface turbulent affected by the solar radiation is the main factor to influence the diurnal variation of wind speed in dry land,while that in Panjin wetland reflects the characteristics of thermal difference between land and water.Due to the water coverage on the land surface in wetland,there are higher evapotranspiration amount and leaf area index,which slows down the changing rates in temperature and relative humidity near the land surface layer,and can effectively reduce the wind speed.This kind of ecological functions to regulate the regional microclimate in wetland is better than that in dry land.This study provides a reference for the evaluation of the impact of wetland in the Liaohe River Delta on the regional climate and their ecological and environmental effects.

Key words: Reed wetland, Maize dry land, Near surface layer, Microclimate