鄂尔多斯高原近40a气候变化研究

Study on Climatic Change of Last 40 Years on Erdos Plateau

鄂尔多斯高原特殊的地理位置对全球气候变化更为敏感,利用1961—2000年地面气温和降水记录,通过计算气候趋势系数和气候倾向率描述鄂尔多斯高原气候空间变化特征。结果表明,40 a来本区气温有明显上升趋势,平均气温以0.43℃.(10a)-1幅度升高。全年各月气温都在上升,但冬季升温最剧烈,达0.82℃.(10a)-1,其中12月可达1℃.(10a)-1,为全年之首。夏季最弱,仅0.31℃.(10a)-1。本区增温幅度比较剧烈,大于内蒙古全区平均水平。冬、夏增温差异导致气温年较差减小。20世纪60年代年平均气温是下降的,从70年代开始上升,90年代上升最剧烈。冬季温度变化与年均温一致,但夏季不同,90年代以前夏季温度是降低的,到90年代夏季温度上升趋势十分明显。温度升高的程度存在区域差异,西北部最强,东南部最弱。降水的趋势变化不很明显,年降水量略有减少,秋季降水量减少比其他季节明显。降水变化也有区域差异,南部比北部降水量减少明显,毛乌素沙漠及以南降水倾向率为-18.3 mm.(10a)-1,而北部接近于零。气候变暖会使蒸发量增大,从而导致干旱,气温持续增高再加上降水量减少则形成干旱化,对生态环境和地方经济会产生重大影响。

Erdos Plateau is more sensitive to the global climate change due to its particular terrain situation. Based on record of air temperature and precipitation from 1961 to 2000, the characters of climate change on Erdos Plateau have been analyzed by calculating climate trend coefficient and climate tendency ratio. It is showed that the air temperature of the area has markedly ascended in the last 40 years, and the increase of annual mean temperature was 0.43℃· （10a）^-1. The air temperature in all months of the year was on the rise. The increase of air temperature in winter was 0.82℃· （10a）^-1 and was the most sharply, among which the increase in December could be 1℃·（10a）^-1 ： Whereas, the increase of air temperature in summer was only 0.31℃·（10a）^-1, which was the smallest of the year. The increase of air temperature in this area was more remarkably than that of the average level in Mongolia. For details, the mean air temperature in 1960s was dropping, whereas that in 1970s was rising and that in 1990s was the most rising. The air temperature change in winter was accord with the change of the annual average air temperature. But that in summer was different： dropping before 1990s but obviously rising when entering 1990s. The rising degree of air temperature was regionally different： from the most in northwest to the least in southeast. The variation trend of precipitation was not obvious, only the annual precipitation reduced a little and the decrease of precipitation in autumn is more obviously compared with that in the other seasons. The variation of precipitation also differed regionally： more obviously in south than that in north. The precipitation tendency ratio of the Mu Us Desert and its southward was -18.3 mm·（10a）^-1, whereas that in north closed to zero. The warming up of climate will make evaporation increase and result in drought. The lasting rising of air temperature and the reducing of precipitation will bring on aridification, which has a great influence on eco-environment and local economy.