腾格里沙漠东南缘沙坡头地区防护林建设与生物气候关系的研究

运用实验生态和生态动力学,生态气候学的原理、途径和方法,研究在降水180毫米左右的草原化荒漠地区,依天然降水建立人工生态防护体系机理、演替变化。大气降水是本区植物繁衍的主要补给源。自八十年代以来降水有减少趋势,但年内分配趋于均匀,相对来说提高了降水对植物补给的有效性。流动沙丘和固沙初期沙丘体为一半封闭系统;在固沙年代较久的地区,由于沙丘表面生物结皮的发展,植物生长消耗了沙丘体内的贮持水量,沙体水分枯竭呈一封闭系统。固沙植物、微气候和沙地水分间形成一复杂的循环系统。据对流沙、1964和1981年固沙地水分动态与空气相对湿度、气温、降水、生物结皮、植被总盖度等关系分析,建立了数值模型。吸湿凝结水包含着分子吸湿和热力学二个过程,微气候因子影响并制约着吸湿凝结的过程和数量,它们从不同矢量方向参与和制约着热动力学过程。水面蒸发它包含了温度,相对湿度和风速三个要素,建立数值模型可揭示其影响的方式和强度。

STUDY ON THE RELATIONS BETWEEN BIO-CLIMATE AND SHELTERBELTS ESTABLISHMENT AT SHAPOTOU AREA IN THE SOUTHEASTERN MARGIN OF TENGGER DESERT

By the principle, way and method of experimental ecology and ecolog-ical kinetics and ecological climatology, we make researches on the mach-anism and succession changes of artificial eco-system protection in the steppe desert area with a precipitation of about 180mm. The precipitation isa main replenishment sources for plant growth in this area. Since 1980s,the precipitation is reduced, the rainfall distribution is tend to be evenin a year. It is relatively speaking that the effectiveness of precipitationto the plant is increased. The shifting sand dune and initial-stage fixed dune are as a halfclosed system. Because of the bio-crust development on the dune surfacein the long-time fixed-dune area, the plant cosumes the water in the sanddune, which makes the water tend to be exhausted. Therefore, it presentsa closed system. The plant for sand fixation, microclimate and sandy landmoisture are formed a complex circle system. We have set up a data modelon the basis of analysis of the relations among shifting sand, moisturedynamic, relative air-humidity, temperature, precipitation, bio-crust,total vegetation coverage and so on. The condensed water covers two processes of molecular absorbtion andthermodynamics. The micro-climatic factors influences and limits the pro-cess of absorbing condensation, participating and conditioning the thermo-dynamics process from different vetor direction. The water surface evapor-ation contents three essential factors of temperature, relative humidity andwind velocity.The data model establishment can show the way and intensityof its influences.