宁夏中部干旱带生态变化与沙尘暴发生的关系分析

利用TM遥感资料, 结合8大类土地详查资料, 基本查清了位于宁夏中部干旱带具有代表性的沙尘暴高发区盐池县20世纪90年代年际变迁量化特征。分析表明, 盐池县90年代初期的生态状况明显好于末期。气候干旱是导致生态变化的主要原因, 但人为活动如大量开垦耕地、过牧及滥挖甘草等也是重要因子。依据沙尘暴的成因, 通过对近30年盐池县沙尘暴个例多源资料综合分析, 局部治理整体恶化的生态现状导致了沙尘暴起暴阈值的明显下降, 即近30年来沙尘暴在宁夏中部的干旱地带发生机率已显著提高。由于造成我国西北地区土地荒漠化的气候、水资源短缺、土地资源超载等因素在可预见的一个相当长的时期将难以得到较大的改善, 且干旱区的生态环境具有脆弱性、易损性、难复性等特点, 该文通过较全面客观的量化分析, 初次提出今后我国西北地区的沙尘暴发生机率应处在上升的态势之中。

An Analysis on the Relationship Between the Ecological Change and Sandstorm in the Drought Zone of Middle Ningxia

The year to year quantificational change characteristics in Yanchi county of the drought zone of the middle Ningxia where occurred sandstorm frequently in the 1990s were revealed on the whole by using TM remote sensing and land survey data. Analyzed results show that ecological condition in Yanchi county in the early 1990s was obviously better than that in the late 1990s. Drought was mainly reasons caused ecological change. Human activity, such as land over cultivated on a large scale, over pasturage and digging the liquorice in excess, however, was another important reason. It was the situation of ecological environment became worse and worse in whole and got better in part that caused the fall in threshold of dust blowing. The probability of sandstorm occurrence had been increased remarkably in the drought zone of middle Ningxia in the past 30 years according to the analysis of the cause of sandstorm and by mean of synthetically analysis of individual cases of thirty year sandstorms in Yanchi county. Due to those factors: climate,water resource shortage and land overloaded etc which caused desertification in western china would not be improved in predictable long term period in future, moreover , ecological environment is frangible, easy to ruin and difficult to resume , and with the objective quantificational analysis on data, we put forward a point in the first time of that the probability sandstorm occurrence in western china would be in the ascending situation from now on.