Measurements of particulate matter(PM),i.e.,PM10,PM2.5,and PMl,have been performed on the Canton Tower,a landmark building in Guangzhou,at heights of 121 and 454 m since November 2010,using a GRIMM 180 aerosol particle spectrometer(Germany).Analyses of data from November 2010 to May2013 showed that the annual average values of PM10,PM2.5,and PMl at the observation height of 121 m above the ground were 44.1,38.2,and 34.9μg/m3,respectively,and those at 454 m above the ground were 35.7,30.4,and 27.5 μg/m3,respectively.By considering the values of the secondary concentration limits given in the Ambient Air Quality Standards issued in 2012,it was observed that the annual average values of PM10 at the observation heights of 121 and 454 m,as well as those of PM2.5 at 454 m,reached those standards.Furthermore,the over-standard amplitude of the annual average value of PM2.5 at the observation height of 121 m was 9.1%.During the observation period,the maximum daily average values of PM10,PM2.5,and PM1 at the observation height of 121 m were 183.3,144.8,and 123.8 μg/m^3,respectively,and those at 454 m were 102.8,92.7,and 86.4 μg/m3.The daily average values of PM 10 at the observation height of 454 m were not above the standards.The over-standard frequencies of the daily average values of PM10 and PM2.5 at the observation height of 121 m were 0.6%and 10.7%,respectively,and the over-standard amplitudes were 9.0%and 24.4%,respectively.The over-standard frequency of the daily average value of PM2.5 at the observation height of 454 m was 2.0%,and the over-standard amplitude was 10.4%.Accordingly,it can be stated that the air at the observation height 454 m above the ground did not reach the secondary limit of the new standards.The pollution was most serious during winter,and the air was relatively cleaner during summer.Overall,the vertical distributions of PM 10,PM2.5,and PMl decreased with height.The lapse rates showed the following sequence:PM10 > PM2.5 > PM1,which indicates that the vertical distribution of fine particles
Xuejiao DengFei LiYuanhong LiJianyong LiHongzhi HuangXiantong Liu
基于LIS和Latent Heat Research Product等TRMM卫星产品及广东省闪电定位仪观测资料对广东雷电活动进行了分析,结果发现:粤北、粤东和粤西等convLHMean(对流潜热)上下层差值为50K/h以上的较大正值区域基本对应着较高的山脉地形,说明对流潜热的垂直变化与广东地区山地抬升作用有一定的关系;而通过分析不同高度convLHMean差值的分布,发现不同区域生成雷电需要的对流潜热条件不稳定高度是不一样的,另外上下层convLHMean差值大值中心分布与陆地、海上及海岸带的flash闪电中心分布基本对应;还发现珠江三角洲地区闪电密度与上下层convLHMean差值的季节变化基本上呈现出相同位相的关系,其相关系数为0.65,且达到了99.9%的信度水平。此外,还发现由于西江的convLHMean分布特征,使得西江存在于较大的不稳定对流潜热能量区域中,顺着河流容易出现大片的雷电密集区域。最后,通过分析上下层convLHMean差值情况,发现在各种天气系统触发作用下,会释放出由下垫面地形抬升作用长期积蓄的这些对流潜热能量,从而引起强烈的雷电活动。
