呼和浩特市与包头市沙尘暴时空分布规律的比较研究

Spatial and temporal distribution of sandstorms in Huhhot and Baotou

文中采用1955～2001年呼和浩特和包头两个气象站的沙尘暴观测资料,分析比较了两个城市的沙尘暴在年、月、日、起始时间上的不同规律。结果显示,从1955年到2001年的47年间,包头共发生沙尘暴1476次,年平均31.4次;而呼和浩特共发生1356次,年平均28.9次。主要集中在3～6月份,包头和呼和浩特在这4个月中的沙尘暴发生次数分别占总数的60.6%和60.9%。在一天内,从中午12时起到下午17时、20时是沙尘暴发生的高峰期,虽然只有6个小时,却占总沙尘暴发生次数的一半。两个城市的沙尘暴持续时间50年代、80年代相差不大,90年代呼和浩特较包头长近一倍,60年代和70年代包头的持续时间较呼和浩特长3～5倍,总体上包头的沙尘暴持续时间长于呼和浩特2.2倍。呼和浩特和包头两个城市沙尘暴的发生是相对独立的,呼和浩特47年间发生沙尘暴1356次,有592次是与包头在同一天内发生的,其中有213次是在晚于包头2个小时后发生的,仅占呼和浩特发生沙尘暴总数的15.7%。在包头市发生沙尘暴后的2～3小时内呼和浩特市也发生沙尘暴的比例为1.5%。由此可以推断,呼和浩特沙尘暴的发生与上风源地包头市关系不大。

Careful analysis was carried on in comparing the starting time differences of sandstorms between the cities of Huhhot and Baotou by applying dataset from two weather stations in each place respectively between the year of 1995 and 2001. The results demonstrated that there were 1476 occurrences of sandstorms in Baotou which meant the annual average rate of 31.4,while the total number reached 1356 with the average of 28.9 annually in Huhhot across the this span of 47 years. Sandstorms intensively occurred across March to June during the period the frequencies accounted for 60.6%and 60.9%on the whole year scale in Baotou and Huhhot respectively. Sandstorms were proved to concentrate during 12AM to 17-20PM on the day. Though only six hours,that period witnessed half of sandstorm happenings. The duration of sandstorms maintain basically the same between the two cities in 1950s and 1980s. In 1990s,Huhhot showed two times of sandstorm duration than Baotou did. When it came to 1960s and 1970s,the sandstorms lasted as much as 3-5 times longer in Baotou than in Huhhot. But overall,Baotou exhibited 2.2 times longer sandstorm duration than Huhhot did. The occurrences of sandstorms in the two cities were independent of each other. 592 out of 1356 records in Huhhot were in the same day with Baotou.Among them,213 happened 2 hours later than that in the other city ,accounting 15.7% of the total number.Thus ,it inferred a less relevant occurrence of sandstorms between the cities of Huhhot and Baotou which is also the upper source of wind.