乌鲁木齐近30年低能见度气候特征  

Climatic characteristics of low visibility in Urumqi City in recent 30 years

作　　者：李景林[1] 郑玉萍[1] 赵娟 胡岩[1] 

机构地区：[1]乌鲁木齐市气象局,新疆乌鲁木齐830002 [2]融安县气象局,广西柳州545400

出　　处：《干旱区地理》2008年第2期189-196,共8页Arid Land Geography

基　　金：新疆气象局科研项目(200309)资助

摘　　要：为探寻乌鲁木齐市低能见度的变化规律，分析城市发展、大气污染对能见度的影响，利用乌鲁木齐市气象站的常规气象资料和环境监测站的大气污染资料对乌鲁木齐近30年低能见度进行统计分析，结果表明：大部分低能见度出现在11月至次年3月份，占全年总次数的97％，出现频率为4．5％，其中12月份出现频率最高，为7．4％；夏半年低能见度出现频率很低，6～8月几乎没有低能见度出现；夜间20时至早晨08时是低能见度的高发时段。近30年低能见度的年出现频率随年代增加而减小的倾向度为0．52％／10a。冬半年和夏半年低能见度出现频率随年代增加而减小的倾向度分别为0．68％／10a和0．08％／10a。低能见度出现时相对湿度≥85％，同时伴有24小时正变湿、负变温、负变压，冬半年平均风速〈2m／s；浓雾、低空逆温及大气污染是造成乌鲁木齐市低能见度的主要原因。本文还对城市化发展、空气污染对能见度的影响进行了正反两个方面的讨论，认为冬半年低能见度出现频率随年代增加而减小的速率远远大于夏半年的原因除气候变化外，与乌鲁木齐加大冬季大气污染治理，实施集中供热有关。In order to find out the changing rules of low visibility in Urumqi city, to analyze the effect of urban development and air pollution on visibility, and to make use of the routine data from Urumqi Meteorological station and the atmospheric pollution data from the environmental monitoring stations, the analyzed statistically the low visibility in Urumqi in recent 30 years. The results indicate that most low visibility appears in Nov. to the next Mar. and accounts for 97% of the total number of a year. The occurrence frequency is 4.5% in one year, the highest frequency is 7.4% occurred in Dec. and the lowest frequency appears in six months summer half-year; and low visibility almost does not appear from Jun. to Aug. ; the time interval of higher frequency of low is from 20 p. m. to 8 a.m. of next day. The yearly occurring frequency of low visibility is decreasing in recent 30 years and its rate of decline is 0.52%/10a; and the rates in winter half-year and six months of summer half-year are 0.68%/10a and 0.08%/10a, respectively. When low visibility occurred, the relative humidity is ≥85%, at the same time with 24 hour positive change of humidity, negative change of temperature and negative change of pressure, and the wind speed is 〈 2m/s in winter half-year. The main reason causing low visibility in Urumqi is heavy fog, low altitude inversion and atmospheric pollution. This paper also discusses the positive and negative impact of urban development and air pollution on the low visibility. Besides the climate change factor, the cause for the decreasing rate of occur- ring frequency of low visibility in winter half-year being far greater than that in six months of summer half year is the measures of strengthening control on air pollution and actualizing the centralization heating adopted in Urumqi city.

关 键 词：低能见度 气候特征 乌鲁木齐 

分 类 号：P427.2[天文地球—大气科学及气象学]