酸雨观测中pH测量负偏差的统计分析  

The Statistical Characteristics of pH Measurement Bias in the Monitoring Data of CMA-ARMN

作　　者：汤洁[1,2] 巴金[2] 

机构地区：[1]中国气象局气象探测中心,北京100081 [2]中国气象科学研究院,北京100081

出　　处：《应用气象学报》2013年第1期55-64,共10页Journal of Applied Meteorological Science

基　　金：公益性行业(气象)科研专项(GYHY200906038);中国气象局气象关键技术集成与应用项目(CAMGJ2112M71)

摘　　要：该文对1992—2011年的酸雨观测资料中存在的pH测量负偏差进行统计分析。结果显示:除西北地区、青藏高原外的大部分酸雨观测站不同程度地出现pH值测量负偏差,总体上南方地区台站的pH测量负偏差问题较北方地区突出;随着测量仪器的更新换型、观测业务规范化管理水平的提升以及一些针对性技术措施的实施,存在pH测量负偏差问题的观测台站比例从20世纪90年代的40%以上下降为25%,观测资料中受pH测量负偏差影响的数据比例由10%下降到2%。pH负偏差的量值与降水pH值之间存在一定依存关系:降水pH值越低,负偏差问题越严重,pH负偏差的主要量值分布区间为-0,6～1,约占负偏差数据的80%。Precipitation pH and conductivity are measured routinely in the nation-wide network with more than 300 stations, known as the Acid Rain Monitoring Network （ARMN）, under the infrastructure of China Meteorological Administration （CMA） since early 1990s. Previous studies indicate that a systematic nega- tive bias in the pH measurement, caused by the aging of pH electrode, which has weakened the data quali- ty obviously. Characteristics of the bias are investigated to describe the temporal and spatial features of the negative pH measurement bias （NBpH） and to estimate its magnitude with meticulous statistical approa- ches, based on the monitoring dataset obtained from CMA-ARMN during 1992--2011. The result indi- cates that 40~ stations of CMA-ARMN suffers from NBpH problem in the early 1990s, while this ratio deereases to 25G during 2010--2011. The proportion of data infected with NBpH problem during 2010-- 2011 reduees to 2o//oo from 10~ in the early 1990s. This improvement of pH measurement mentioned above can be attributed to the renewal of pH meter for all CMA-ARMN stations in 2000, the re-approval of Standard Operation Manual of CMA-ARMN in 2005, and the recent trail measures on the pH electrode ag- ing. Also, statistics shows that NBpH problem seldom occurs in the stations over the Northwest China and Qinghai-Tibet Plateau, but frequently occurs in the stations of other regions over China. On the whole, NBpH problem in southern part of China is more serious than those in the northern part of China. This geographical feature of NBpH is related with the behavior of aged pH electrode which shows bigger negative bias when measuring the solution of low pH and low conductivity. Quasi-quantitative estimation of NBpH based on the K-pH inequality principle shows that the magnitude of NBpH for about 80~ data ranges from --0.6 to 0, with a few of extremes lower than --3.0. The lower pH is, the larger NBpH tends to be. To avoid NBpH problem in future, substitution of the now-using normal pH eleetrode in CMA-ARM

关 键 词：酸雨观测 PH测量 负偏差 统计分析 数据订正 

分 类 号：P416[天文地球—大气科学及气象学]