关键词: 绿洲效应, 空气逆湿, 土壤逆湿, "呼吸"过程

Abstract: In this paper,by utilizing the data of the observation(August-September 2000) of Dunhuang,which was observed in Land-atmosphere Interactive Field Experiment over Arid Region of Northwest China,the characteristics of the soil moisture,atmosphere humidity are analyzed.It is found that air humidity in the active soil layer is far from saturated state,and the soil moisture exists and transfers as gaseous state and liquid state separately.Because of influence of oasis,over desert or Gobi near the oasis,atmospheric humidity not only often appears inverse gradient in surface layer,but also the inverse humidity can extend to soil surface at night.Daily variation of soil moisture can be clearly divided into 4 stages:wet stage(at 1:00~6:00),moisture loss stage(at 7:00~11:00),dry stage(at 12:00~18:00) and moisture take-up stage(at 19:00~0:00).It is shown that surface soil has inverse wetness at late night,and can absorb moisture from the air through condensation in night.This process and soil moisture evaporation process in daytime combine into a respiration process of soil moisture.And the formation of inverse humidity of surface soil is relative to the state of surface temperature,intensity of inverse humidity of atmosphere and atmospheric stability.

Key words: oasis effect, air inverse humidity, surface soil inverse wetness, respiration process