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中国沙漠 ›› 2008, Vol. 28 ›› Issue (2): 332-337.

• 天气与气候 • 上一篇    下一篇

新疆区域大气透明度研究

胡列群; 吉海燕
  

  1. 新疆气象局, 新疆 乌鲁木齐 830002
  • 收稿日期:2007-02-12 修回日期:2007-04-30 出版日期:2008-03-20 发布日期:2008-03-20

Research on Atmospheric Transparency in Xinjiang

HU Lie-qun, JI Hai-yan
  

  1. Xinjiang Meteorology Bureau, Urumqi 830002, China
  • Received:2007-02-12 Revised:2007-04-30 Online:2008-03-20 Published:2008-03-20

摘要:

在分析新疆区域大气透明度过程中,为克服福布斯(FORBERS)效应,即大气质量M对太阳光谱成分变化产生的干扰,将复合透明度系数Pm订正到相对大气质量M=2(H=90°)时所计算出来的积分透明度P2来进行描述。利用乌鲁木齐、喀什40多年长序列太阳辐射资料以及塔克拉玛干沙漠腹地及周边地区相关的辐射和气象资料,分析新疆区域大气透明度的年际、月际和日变化以及影响大气透明度的主要气象因子。结果表明,乌鲁木齐、喀什的大气透明度在40多年中,其年际变化特征主要表现为P2呈逐步下降的趋势,这种下降在20世纪90年代至今的近20 a里有加速的趋势;从季节角度分析,P2的这种逐年代下降的趋势在冬季(1月)和春季(4月)更为显著,而在夏季(7月)和秋季(10月),这种下降则较为温和,无论乌鲁木齐还是喀什,以十年段平均值的振幅来看,乌鲁木齐P2在1月和4月均在0.2以上,而7月和10月则均在0.2以下,表现的更为明显,喀什亦有类似特征;新疆大气透明度在一年中的变化,以冬季为最佳,秋季次之,春季最差,近年来,乌鲁木齐地区冬季大气透明度急剧下降,其最高值已出现在秋季,喀什也呈现出同样现象,这表明了在城市化情况下,以人类活动影响因素为主所导致的大气污染,使空气的透明状况越来越差;新疆大气透明度的日变化表现为早晚高、中午低的特点,其逐日变化则与天气过程相关联;新疆的下垫面多为沙漠、戈壁,大气中的尘埃含量和水汽压变化是新疆大气透明度的重要影响因子,尘埃含量的变化是塔里木盆地大气透明度变化的最重要影响因子,其与大气透明度的变化呈反相关,而水汽压的变化亦与大气透明度变化呈反相关关系。

关键词: 新疆, 大气透明度, 年际变化, 影响因子

Abstract:

The Integral transparency P2, which is corrected by the composite transparency coefficient Pm corresponding to the atmosphere mass M=2 (H=90 degree), is defined as the atmospheric transparency index in order to get over the FORBERS effect (namely disturbance to solar spectrum component variations caused by atmosphere mass). Based on the solar radiation data more than 40 years in Urumqi, Kashgar, and the correlative radiation data and meteorological data in Taklimakan desert hinterland and its adjacent regions, the annual, monthly and daily variations of atmosphere transparency P2 are analyzed. Furthermore, the primary meteorological factors influencing P2 are also discussed. The results show that the annual P2 of Urumqi and Kashgar gradually went down in recent 40 years, and the descending trend accelerated from 1990s. The decadal descending trend of P2 is remarkable in winter (January) and spring (April), but slight in summer (July) and autumn (October). The decadal anomalies of P2 in Urumqi and Kashgar are more than 0.2 in January and April, and less than 0.2 in July and October. The P2 of Xinjiang is the best in winter, second in autumn, and worst in spring. But the winter P2 in Urumqi during the recent years rapidly declines, the highest P2 is in autumn; this similar change also appeared in Kashgar. It is implied that atmospheric pollution mainly caused by human activity is resulting in the worse atmospheric transparency condition in urbanization background. The diurnal variation of P2 in Xinjiang is a concave curve: high in the morning and at night, low at the noon; its daily variation relates to weather process. As a result of the land surfaces are mostly covered with desert and Gobi, the important factors influencing the P2 of Xinjiang are dust content and water vapor pressure change; especially the factor of dust content is the most important factor influencing the P2 variation of the Tarim basin. There is a negative correlation between dust content and P2, a positive correlation between vapor pressure and P2.

Key words: Xinjiang, atmospheric transparency, inter-annual variation, influencing factors

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