1981—2014年四川不同强度霾时空特征及气候成因研究

发布时间：2018-01-22 02:06

本文关键词： 霾逆温层青藏高原相对湿度能见度　出处：《环境科学学报》2016年12期 　论文类型：期刊论文

【摘要】：利用四川156个气象观测站1981—2014年霾日观测资料,对区域内不同强度霾日的时空分布特征及变化趋势进行分析.结果发现:不同强度霾日数呈现轻霾和重霾显著上升、中霾下降的趋势,20世纪90年代后霾日整体偏多,其中,秋、冬季发生频率偏高,12月和1月是多发时段;不同强度年均霾日高值区集中在盆地中部、东部地区,低值区主要位于盆地西南地区,并呈现盆地中北部霾日逐年减少,盆地南部逐年增多的变化趋势.结合季节特征探讨霾日形成机理发现,春、夏季欧亚中高纬度呈现两槽一脊的环流形势,印缅槽较强,利于降水,盆地相对湿度为85%以上,高原东侧上升气流较明显,大气对流层中下层为"上冷下暖"的递减层结,利于大气污染排放物垂直交换及其对外扩散;秋、冬季高纬度以纬向环流为主,经向环流偏弱,冷空气被阻挡在盆地以北以西区域,盆地东部为下沉气流,850 h Pa以下的偏东气流使东部污染物向西蔓延,青藏高原以东地区上空为显著的"上暖下冷"逆温层结,相对湿度为80%左右,地面气温增加,相对湿度下降,使霾不易向雾转换,加重霾日高频状况的发生.
[Abstract]:The Haze Day data of 156 meteorological stations in Sichuan Province from 1981 to 2014 were used. The spatial and temporal distribution characteristics and variation trend of haze days with different intensity in the region were analyzed. The results showed that the number of haze days with different intensity showed a significant increase of light haze and heavy haze, and a decreasing trend of moderate haze. After 1990s, there were more haze days on the whole, among which, autumn and winter occurred frequently, and December and January were the most frequent periods. The average annual haze daily high value area of different intensity is concentrated in the middle of the basin, the eastern area, the low value area is mainly located in the southwest area of the basin, and the haze day in the central and northern part of the basin decreases year by year. Combined with seasonal characteristics, the formation mechanism of haze in the southern part of the basin is discussed. It is found that in spring and summer, the circulation pattern of two channels and one ridge appears in the middle and high latitudes of Eurasia, and the Indo-Myanmar trough is stronger, which is favorable to precipitation. The relative humidity of the basin is above 85%, the updraft of the eastern side of the plateau is obvious, and the middle and lower troposphere of the atmosphere is a descending layer of "upper cold and lower temperature", which is conducive to the vertical exchange and outward diffusion of air pollution emissions. In autumn and winter, the zonal circulation is dominant in the high latitudes, the meridional circulation is weak, the cold air is blocked in the area to the north and west of the basin, and the downdraft is in the eastern part of the basin. The easterly flow below 850hPa makes the pollutants spread westward in the east of Qinghai-Xizang Plateau. There is a significant "upper warm and lower cold" inversion layer over the east of the Qinghai-Xizang Plateau. The relative humidity is about 80%, and the surface temperature increases. The decrease of relative humidity makes it difficult to convert haze to fog, and increases the occurrence of high frequency condition of haze day.
【作者单位】：四川省气候中心;高原与盆地暴雨旱涝灾害四川省重点研究室;四川省气象探测数据中心;
【基金】：2015年中国气象局气候变化专项(No.CCSF201532) 国家科技支撑计划项目(No.2014BAC16B03)~~
【分类号】：X513;X16
【正文快照】： 1引言(Introduction)随着经济发展的加快和城市扩大化,汽车尾气排放及人为影响已导致大气气溶胶的污染日益严重,霾作为一种污染型天气现象越来越受到广泛关注.重雾及灰霾天气不仅造成交通阻塞、交通事故频繁发生,而且空气中的污染物还会严重危害到人类的身体健康.根据相关权威

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