内蒙古奈曼麦田和沙丘微气象特性研究

STUDY ON MICROMETEOROLOGICAL CHARACTERISTICS OVER WHEAT FIELD AND SAND DUNE AT NAIMAN, INNER MONGOLIA, CHINA

本文分析了内蒙古奈曼旗尧勒甸子村麦田冠层上方和流动沙丘的微气象特性。结果表明:(1)麦田和沙丘的反射率分别为21％和34％;(2)麦田白天约有60％的净辐射用于潜热交换,夜里净辐射的大部分来自土壤热交换(35％)和潜热交换(41％);沙丘白天约48％的净辐射用于土壤热交换,夜里有52％的净辐射由土壤热交换补给。(3)波文比在麦田和沙丘都是早晨和夜间大,白天小。(4)白天麦田上方的水汽压低于近麦层的,夜里则相反;沙丘上的水汽压在一天中绝大部分时间里高处高于低处(近地表)。(5)最低测点平均风速与最高测点平均风速之比,麦田和沙丘都是白天高,夜间低;沙丘比麦田高。摩擦速度与最高测点平均风速之比白天低,夜里高;沙丘比麦田低。

In this paper, the micrometeorological characteristics and the heat budget over the wheat field and the sand dune in Yaoledianzi village, Naiman, Inner Mongolia are analyzed. The results show that: (1) Albedo for the wheat field and the sand dune is about 21% and 34%, respectively. (2) Over the wheat field, about 60% of the net radiation in daytime is spent for the latent heat flux, and about 41 % of the net radiation at night is supplied by the latent heat flux, about 35% by the soil heat flux. Over the sand dune, 48% of the net radiation in daytime is spent for the soil heat, and about 52% of the net radiation at night is provided by the soil heat. (3) Bowen ratio in the early morning and at night is higher than that in daytime. (4) The ratio of the wind speed (u5), at the lowest measurement site to that (u1) at the highest site is higher in daytime than at night, and higher over the sand dune than over the wheat field. Ratio of the friction velocity (u*) to the wind speed (u1) is lower in daytime than at night, and lower over the sand dune than over the wheat field.