【作者】 薛忠歧；

【导师】 卢耀如； 万力；

【作者基本信息】 中国地质大学（北京） ， 水文学与水资源， 2006， 博士

【摘要】 宁夏地处干旱半干旱地带,是全国生态环境最突出、生态系统最脆弱的省区之一。恶劣的生态环境问题严重制约着宁夏经济、社会的可持续发展。从2002年起,国家为了缓解黄河断流问题,逐年压减宁夏黄河引水量,水资源短缺加剧了宁夏生态环境的恶化,造成主要环境因素组合不协调,自然生态系统功能偏低,环境容量较小,生态平衡脆弱。 本文在总结大量国内外文献的基础上,利用美国航天局发布的最新全球植被指数数据GIMMS NDVI和高分辨率的MODIS NDVI对宁夏全区1982—2004年的生态植被变化趋势进行了研究,结果表明,在1982—1999年间,宁夏全区除盐池一麻黄山地区外,其余地区的植被发育趋势较好,但是从2000后随着引用黄河水量的逐渐减少,宁夏地区银川平原、中宁平原以及扬黄工程红寺堡灌区的植被均出现了轻微退化。通过对气象因素的分析可以看出,盐池—麻黄山、贺兰山及六盘山区的植被主要受降雨量的影响,而红寺堡地区的植被退化主要受扬黄工程的影响,是次生盐渍化的结果。 银川平原位于宁夏回族自治区北部,面积7790km~2,在宁夏占据非常重要的地位。根据本文研究成果,银川平原的生态植被主要受引用黄河水量的影响,是由于引用黄河水量的减少导致地下水位下降而引起的。 同时,通过地下水位模拟和植被覆盖率的对应关系的探讨,得出银川平原最适宜绿洲生长的水位埋深为3m左右,区间值为2—4m,当水位埋深小于2m时容易形成盐渍化地带,水位埋深大于4m时,地下水对植被的补给能力变弱,两种情况都不利于植物生长。 最后,论文对银川平原绿洲的生态需水量进行了计算。银川平原如果要维护植被正常生长和不出现退化趋势,需要的最小生态环境需水量为49.56亿m~3。通过模拟地下水位埋深与蒸发量的关系,可以发现当潜水水位埋深大于3m时,水位埋深对蒸发的影响会很小。更多还原

【Abstract】 Located in arid and semi-arid area, Ningxia is one of the areas with weakest ecological environment. The weak eco-environment restricts the economic and social development of Ningxia province. From 2002 onwards, the water allocation of Ningxia area has been decreased in order to solve the problem of water inception for Yellow River. The shortage of water resources made the eco-environment become worse and induced the composition of main environmental factors incompatible. The natural function of eco-system became low, the environmental capacity became little and the ecological balance is weak.On the basis of summarizing many national and international references, this research studied the variation of ecological vegetation from 1982 to 2002 in Ningxia area by using GIMMS NDVI and MODIS NDVI which was issued by NASA. According to the result, from 1982 to 1999, the development of vegetation in most areas was good except Yanchi-Mahuangshan area. However, after 2000, with the decrease of water allocation of the Yellow River, the vegetation of Yinchuan plain, Zhongning plain and Hongsipu area began recession in small extent. Based on the analysis of meteorological data, the vegetation in Yanchi-Mahuangshan area, Helan mountain area and Liupan mountain area are influenced by precipitation. The recession of vegetation in Hongsipu area was the effect of secondary salinization which was induced by human activity.With area of 7,790 km~2, Yinchuan plain is located in north area of Ningxia province and has a very important position in social and economic development. In this paper, the principle of vegetation recession in this area was discussed in detail. According to the result, the ecological vegetation in Yinchuan plain was influenced by water allocation of the Yellow River. The main reason of the recession was the descending of the groundwater level which was induced by decreasing of water allocation from the Yellow River.The relationship between groundwater level and vegetation development wasalso discussed in this paper. The proper water level for the development of vegetation is 3 m and the interval is 2m to 4m. It would induce soil sanilization if the water depth is lower than 2m and the groundwater supply is less for vegetation if the water depth is more than 4m.At last, the ecological water demand of Yinchuan oasis was calculated in this paper. The smallest ecological water demand is 49.56 X 108m3 if the vegetation could developed normally and there is no recession trend in vegetation. The influence of the water depth for evapotranspiration is very small if the water depth is more than 3 m after the simulation of the relationship between ground water depth and evapotranspiration.更多还原