中文摘要：

利用全国681个站的沙尘天气观测资料分析得出,2004年春季中国北方的沙尘天气明显偏少、偏弱,主要表现在：（1）2004年春季681个站累计的沙尘天气日数2 080 d,相当于历史平均值的46.9%,是近四十余年中第三个偏少年份。沙尘暴的总面积约190万km2,仅为历史平均值的37.3%。（2）危害性较大的沙尘暴和强沙尘暴过程6次,不足2001年的一半。（3）4月和5月沙尘天气明显偏少导致整个春季显著偏少。沙尘天气出现时,PM10浓度相对增加,空气质量恶化,但与历史上较典型的强沙尘暴个例相比,PM10浓度增加的幅度不大。进一步分析表明,2004年春季沙尘天气偏少、偏弱的主要原因是大气动力条件不足,是比较特殊的一个年份。

英文摘要：

Using sandy weather data from 681 meteorological stations,it can be analyzed and seen that the sandy weather in northern China in the spring of 2004 was abnormally less and weak in terms of frequency,intensity,area affected,and sandy aerosol. The total number of dusty weather days in the spring of 2004 exceeded only that in 1997 and 2003 ,taking the third place since 1961. Furthermore, the main reason was i＇dentified that the dynamical condition was inadequate in that season. So it was a special year of sandy weather in China.