格尔木市低空逆温特征及其对空气污染物浓度的影响

Characteristics of Temperature Inversion in Lower-air and Its Influence on Concentration of Air Pollutants over Golmud City

利用2015—2017年格尔木市L波段雷达探空站的探空资料,分析格尔木市低空逆温的基本特征,并与不同气候区的西宁市、玉树市做对比;结合2016—2017年格尔木市逐日空气污染物浓度(SO_2、NO_2、O_3、PM_(2.5))资料,研究低空逆温对空气污染物浓度的影响。结果表明:07时、19时格尔木市年均逆温发生频率分别为67%、24%,以贴地逆温为主,秋、冬季发生频率高于春、夏季;逆温厚度表现为早间高于晚间,冬季最厚,夏季最薄,07时各季节贴地逆温厚度高于悬浮逆温,19时秋、冬季悬浮逆温厚度高于贴地逆温;逆温强度表现为贴地逆温大于悬浮逆温;07时悬浮逆温的起始高度和终止高度(分别为331 m、571 m)小于19时(分别为662 m、851 m),均在冬季达到最大;07时柴达木盆地逆温发生频率最高(67%)、强度最大(2.07℃/100 m)、厚度最薄(267m),19时逆温发生频率少于河湟地区,但多于三江源地区(24%),强度最小(2.18℃/100 m),厚度最厚(127 m);逆温对SO_2、NO_2、O_3、PM_(2.5)浓度有显著影响,但对PM_(2.5)的影响效果不如风速明显。

Based on the L-band radar data observed from 2015 to 2017,this paper analyzed the characteristics of low-altitude inversion layer over the Golmud city and compared with Xining and Yushu city that located in different climate zones.Combined with the daily air pollutants concentration data(SO2,NO2,O3 and PM2.5)during 2016-2017 in Golmud city,the impact of low-altitude inversion layer on the concentration of air pollutants were studied.The results showed that the annual average frequency of temperature inversion in Golmud city was 67%at 07:00 and 24%at 19:00,mainly by the near ground temperature inversion,the frequency of temperature inversion was higher in autumn and winter than that in spring and summer.The temperature inversion thickness in the morning was much higher than in the evening,and it was the thickest in winter and the thinnest in summer.The thickness of the grounding inversion was higher than the suspension inversion at 07:00 in each season,the thickness of suspension inversion at 19:00 in autumn and winter was higher than the grounding inversion.The intensity of the grounding inversion was stronger than the suspension inversion.The starting and ending height of suspension inversion at 07:00(331 m,571 m)were less than 19:00(662 m,851 m),and reached the maximum in winter.At 07:00,the temperature inversion of Qaidam Basin had the highest frequency(67%),the strongest intensity(2.07℃/100 m)and the thinnest thickness(267 m).At 19:00,the frequency of the Qaidam Basin was less than the Hehuang area but much higher than the Three-River Source area(24%),have the smallest intensity(2.18℃/100 m)and the thickest thickness(127 m).The temperature inversion had significant effect on concentration of SO2,NO2,O3 and PM2.5,however,the effect on PM2.5 Concentration was less significant than wind speed.