1980—2007年新疆地区能见度的变化特征及其影响因子研究

Variation Characteristics in Atmospheric Visibility and Their Effective Factors in Xinjiang during 1980-2007

在小风、无降水、无大雾等天气条件下,运用能见度累计百分率法和能见度均值法,分析了新疆15个城市1980—2007年间每日14时大气能见度的月分布特征、年际变化趋势及影响大气能见度的影响因子,结果表明:(1)新疆的能见度在夏季出现峰值,冬季降到最小值。北疆地区的能见度总体高于南疆地区。全疆能见度最高的城市是哈密,年均值为49.6 km。和田最低,年均值仅为16.4 km;(2)15个城市中只有阿勒泰、哈密、昌吉3个城市的能见度基本保持不变,北疆博乐、克拉玛依、伊宁、石河子、乌鲁木齐和南疆吐鲁番、阿克苏的能见度逐年降低,南疆阿图什、库尔勒、喀什、和田市的能见度缓慢增加;(3)从气象因素相对湿度、风速、降水、沙尘天气日数的年变化以及全疆经济发展中能源消费总量和能源加工转换总效率来看,15个城市的相对湿度、风速总体上没有呈现显著的变化,降水增多、沙尘天气减少促使南疆大部分城市的能见度逐步好转,而近年来的经济快速增长是导致北疆大部分地区能见度逐年下降的主要因素。

Under the certain conditions with breeze,no-precipitation and no-dense-fog,visibility data of daily 14 o’clock was examined for 15 meteorological stations in Xinjiang during 1980-2007 by using statistical methods such as cumulative percentiles,annual means,and monthly distribution feature,inter-annual change trend and visibility effective factors were analyzed.The research results show：（1）The maximum visibility in Xinjiang occurred in summer and the minimum occurred in winter with higher value in the northern Xinjiang comparing with southern Xinjiang.The annual mean visibility,49.6 km,was the highest in Hami station of,and the lowest,16.4 km,in Hotan.（2）In the past 28 years,the visibility trend changed except for three cities,Altai,Hami and Changji.Visibility at eight cities mainly located in the north of Xinjiang had declined step by step and the rest located in the south of Xinjiang had experienced a gradual raise.（3）Considering meteorological factors and human economical activities,relative humidity and wind speed had not apparently changed in the past 28 years and visibility impairment in major cities of Northern Xinjiang was due to quickly developed economy.In the contrary,improvement in visibility in the southern Xinjiang was attributed to the decrease of dusty events and increase in rainfall.