库布齐沙漠北缘沙丘不同部位露水凝结量的初步研究

Dew-fall in Different Position of Dunes in the Northern Marginal Zone of the Kubuqi Desert

以库布齐沙漠北缘与黄河河岸之间的生态过渡带为研究对象，通过每天野外观测沙丘不同部位的露水凝结量来确定小尺度（典型沙丘的坡位）上露水量的空间分布特征及日平均露水凝结量。结果表明，在库布齐沙漠边缘地区有凝结水存在，它的形成对维系荒漠化地区植被生态系统的稳定至关重要，该区的日平均露水凝结量为0．172～0.324mm，其中丘间地露水凝结量为0．248～0.377mm，阳坡为0．160～0．362mm，阴坡为0．170～0.305mm，沙丘顶部为0．051～0.272mm，而0．03mm的露水量是微生物对于水利用的最低限度，可见露水是该区生态系统中不可缺少的生态因子。沙丘不同部位的露水凝结量不同；露水凝结量从大到小的次序依次为丘间地、阳坡、阴坡、沙丘顶部。同时，阳坡上、下部位之间露水凝结量的差异要比阴坡上、下部位的差异更加明显。这将为在库布齐沙漠开展露水研究是否可行提供依据。也为今后人工促进植被恢复提供理论依据和技术支撑。

A measurement program was carried out with a sand dune belt situated in between the northern Kubuqi desert and riverside of the Yellow River, to measure daily amount of dew deposition during the dew formation for different parts of sand dune, Then we can determine the character of distribution of the amounts of dew in fine scale, The measurement showed that the daily amount of dew ranged between 0.172 mm/night and 0. 324 mm/night and the amount of dew ranged within the four parts of aand dune are 0, 248~0, 377 mm in interdune area,0, 160~0, 362 mm in sun-shaded slope,0, 17~0. 305 mm in shady slope and 0.051~0. 272 ram in the top of sand dune respectively. A value of 0, 03 mm,which also marks the threshold for dew availability for microorganisms.was taken as a threshold for dew, So,dew as a ecological factor in arid and semi-arid ecosystems is indispensable. There is a different quantities of dew-fall in dissimilar part of sand dune. The results showed that the order of the dew-fall quantities from high to low was interdune area）sun-shaded slope）shady slope）the top of sand dune. At the same time,the daily amount of dew in sun-shaded slope is more variable than in shady slope between the the upper position and the lower position the slope.