近45年内蒙古乌审旗气候变化对沙尘天气的影响

Climatic Change and Its Effect on Dust Weather in Uxin Banner of Inner Mongolia in Recent 45 Years

利用1961-2005年内蒙古乌审旗气象台站的地面观测资料,分析气候年代际变化特征,探讨气候变化对沙尘天气的可能影响。结果表明:近45年来,乌审旗年平均气温以0.48℃/10 a的趋势变暖,近5年气温比20世纪60年代升高了1.8℃,1961-1996年为偏冷时段,1996-2005年为偏暖时段。降水量以15.15 mm/10 a的趋势减少,20世纪60年代至21世纪经历了一个"少、多、少、多"的年代际变化过程。降水量变化分4个多雨时段和4个少雨时段。年大风日数以3.53 d/10 a的趋势减少,20世纪60年代是大风天气的频发期,近5年大风日数较60年代减少了197 d。年沙尘天气日数以14.96 d/10 a的趋势减少,20世纪60-70年代是沙尘天气的频发期,近5年较20世纪60-70年代减少了624.5 d;从季节变化来看,沙尘天气多的季节大风也多,气温回升快,降水量偏少;不同年代气候要素的不同组合对沙尘天气的影响有所差异,春季沙尘日数与同期大风日数的正相关较显著,与同期的气温和前一年夏季降水也显现出较好的负相关关系,夏季降水对第2年沙尘天气的预报有一定参考意义。

In this paper, climatic change and its effect on dust weather are analyzed in detail using the meteorological data observed at the meteorological station in Uxin Banner of Inner Mongolia during the period of 1961 - 2005. The results show that the annual temperature was increased by 0.48 % per decade, it was increased by 1.8 ℃ in recent 5 years compared with that in the 1960s, it was cold during the period of 1961 - 1996 but warm during the period of 1996-2005. Annual precipitation was decreased by 15.15 mm per decade, and its decadalchange was in processes of ＂decrease-increase-decrease-increase＂ since the 1960s. The annual days of occurring gale were decreased by 3.53 days per decade, gale occurred frequently in the 1960s, but the days of occurring gale were decreased by 197 days in recent 5 years compared with that in the 1960s. The annual days of occurring dust weather were decreased by 14.96 days per decade, dust weather occurred frequently during the period from the 1960s to the 1970s, but the days of occurring dust weather in recent 5 years were decreased by 624.5 days com- pared with that during the period from the 1960s to the 1970s. Dust weather occurred frequently in the seasons when gale occurred frequently, temperature increased quickly, and precipitation occurred infrequently. The effects of different combinations of climatic factors were different in different years. The days of occurring dust weather had a significant positive correlation with that of occurring gale in spring, but a good negative correlation with air temperature and rainfall in previous summer. Rainfall in summer can be referred to predict the occurrence of dust weather.