大气-植被-土壤之间物质和能量输送过程与机制的分析

THE COURSE AND MECHANISM OF SUBSTANCE AND ENERGY TRANSPORT AMONG ATMOSPHERE-VEGETATION-SOIL

在绿洲—荒漠交界处，由于绿洲荒漠之间的相互影响，相互作用，使得大气—植被—土壤之间的物质和能量交换形成其特有的过程。本文对这些交换过程与机制进行了较为详细、准确的讨论。

On ground surface, there are three balances, i.e. radiation balance, heat balance and water balance. In the transitional zones of desert-oasis, the exchanges of substance and energy among atmosphere-vegetation-soil form the peculiar courses due to the influence and effect of deserts and oases each other. The course and mechanism of substance and energy transport among atmosphere-vegetation-soil are discussed in detail and accurately based on the observed data. The experiments were carried out at Aksu Water Balance Experimen tal Station located at a transitional zone of oasis-desert in Tarim Basin. First, all the components in radiation balance equation are analyzed in the paper. The results show that the contrast of reflechvity (A) is great within oasis farmlands and between oasis and desert. The contrast of effective radiation (F0), however, is small within oasis farmlands, bilt great between oasis and desert. The amount of F0in oases is less than that in deserts. It is obvious that effective radiation is the main factor for causing the contrast of net radiation (Rn) between desert and oasis. The contrast of Rn causes a big contrast of water and heat conditions between oasis and desert, but a small contrast within oasis farmlands. Then, all the components in heat balance equation are analyzed. The results show that the transport course of sensible heat and latent heat in oasis farmlands varies with the change of surface conditions and advection between oasis and desert. There is no synchronism in the daily course of sensible and latent heat fluxes. Lastly, all the components in water balance equation are also analyzed. The results show that the periodical irrigated water makes soil keep a suitable moisture for growth of crops. Meanwhile, the irrigation efficiency of the oasis farmlands in Tarim Basin is about 80%. Irrigated water not only supplies soil layers but also ground water. The present irriga tion practices should be driproved.