排序方式: 共有18条查询结果,搜索用时 31 毫秒
11.
12.
On-line measurement of water-soluble ions in ambient particles 总被引:8,自引:0,他引:8
Combining the system of rapid collection of ambient particles and ion chromatography, the system of rapid collection of fine particles and ion chromatography (RCFP-IC) was established to automatically analyze on-line the concentrations of water-soluble ions in ambient particles. Here, the general scheme of RCFP-IC is described and its basic performance is tested. The detection limit of RCFP-IC for SO2? 4 , NO?3 , NO?2 , Cl? and F? is below 0.3 μg m?3. The collection efficiency of RCFP-IC increases rapidly with increasing sized particles. For particles larger than 300 nm, the collection efficiency approaches 100%. The precision of RCFP-IC is more than 90% over 28 repetitions. The response of RCFP-IC is very sensitive and no obvious cross-pollution is found during measurement. A comparison of RCFP-IC with an integrated filter measurement indicates that the measurement of RCFP-IC is comparable in both laboratory experiments and field observations. The results of the field experiment prove that RCFP-IC is an effective on-line monitoring system and is helpful in source apportionment and pollution episode monitoring. 相似文献
13.
The measurement of column content of carbon monoxide,methane,and other atmospherictraces gases as well as aerosols has been conducted during the fall of 1992 and 1997,using aninfrared spectrometer of moderate resolution in the cooperation of the Laboratory for MiddleAtmosphere and Global Environment Observation(LAGEO),Institute of Atmospheric Physics,Chinese Academy of Sciences,with the Institute of Atmospheric Physics,Russian Academy ofSciences.The variation characteristics of atmospheric CO column content in Beijing area arepresented.The analysis of the measurement shows that the CO column concentration of 0.10 mgcm~(-2)can be considered as the background over Beijing area.and the concentration as high as 0.75mg cm~(-2)was observed under some unfavorable meteorological situations. 相似文献
14.
15.
Ultraviolet (UV) solar radiation has a significant influence on human health, the environment and climate. A series of measurements, including UV radiation (290 400 nm) and global solar radiation (Rs), were continuously recorded from August 2004 at the Lhasa and Haibei sites on the Tibetan Plateau. Both observation sites' altitudes are above 3000 m and have similar meteorological conditions. The data from 2005 2006 was used to identify the varying characteristics of UV radiation. It's relation to the clearness index Ks, the relative optical mass mr, and Rs were established. The annual mean values of total daily UV radiation are 0.92 and 0.67 MJ m^-2 at Lhasa and Haibei, respectively. The UV radiation in Lhasa represented 4.6% of the global solar radiation while in Haibei this percentage was 4.2%. In the case of clear days (Ks 〉 0.8), these percentages ranged between 4.0% and 4.5% in Lhasa and between 5.1% and 5.5% in Haibei. In the case of cloudy days (Ks 〈 0.4), these percentages ranged from 4.4% to 6.8% in Lhasa and from 5.1% to 5.5% in Haibei. The maximum values of UV radiation for each relative optical mass diminished exponentially with mr. Thus, for Lhasa and Haibei, UV=46.25mr-129, and UV=51.76mr-142, respectively. The results of this study can be used to obtain more UV radiation data for the study of UV climate characteristics, the effects of UV on ecological processes and the feedback of the thinning of the stratospheric ozone, from more routine measurements Rs data. 相似文献
16.
不同土壤类型的热通量变化特征 总被引:3,自引:0,他引:3
利用2004—2007年中国科学院中国生态系统研究网络(CERN)生态站实测土壤热通量、辐射等资料,分析了不同土壤类型表层热通量的日变化和季节变化,以及不同土壤类型的热通量与总辐射、净辐射的关系。结果表明,由于导热率越大,热量传输就越快;热容量越小,热量传输也越快,造成土壤热通量的日较差和年较差较大,所以黄绵土和紫色土的表层热通量日较差最大(220~280 W.m-2),高寒草甸土和水稻土最小(55W.m-2);季节变化中土壤表层热通量的年较差变化范围在12~28W.m-2之间,灰漠土最大,为28W.m-2,热通量年较差从大到小依次为灰漠土、黄绵土、盐碱潮土、红壤土、紫色土、沼泽土、水稻土和高寒潮土,高寒潮土最小,为12W.m-2。不同土壤类型的热通量与总辐射、净辐射呈正相关关系,但不同土壤类型的土壤热通量在12:00(地方时)所占净辐射的比例各不相同,高寒草甸土最小,约为8%;黄绵土最大,为38%,多数土壤的热通量占净辐射的比例在15%~20%之间,这充分表明不同土壤类型表层热通量的传输存在很大差异。 相似文献
17.
本文利用“HEIFE”1991年10月加强观测期在平川荒漠地区观测的太阳光谱资料.对平川上空大气中水汽总量和臭氧总量进行了计算。计算指出利用多渡段太阳光谱资料拟合Angstroem参数,并引入1hλ的三次多项式.大大地提高了气溶胶光学厚度的计算精度.在上述基础上计算出平川上空10月份臭氧总量平均为0.323cm-atm,水汽的光学厚度为0.238.分析发现该地区水汽总量与地面相对湿度有较好的相关.其相关系数达0.825。文中对水汽计算的几种方法还进行了比较与讨论。 相似文献
18.
北京城市紫外辐射变化特征及经验估算方程 总被引:10,自引:1,他引:10
利用2004年4月—2005年6月在中国科学院大气物理研究所铁塔分部的紫外辐射观测数据,分析了北京城市紫外辐射的变化特征,结果表明,紫外辐射的变化规律与太阳总辐射一致,紫外辐射与总辐射的比值变化范围在0.02~0.04之间,晴天恒定在0.03,阴天在0.04左右,在沙尘暴过程中比值最小,为0.02。通过分析紫外辐射与大气质量数和平均晴空指数之间的关系,建立了适合于北京的全天候紫外辐射的估算方程。利用建立的估算方程及观测的总辐射值进行了紫外辐射的估算,紫外辐射的计算相对误差在10%以内。 相似文献