The use of trajectory cluster analysis to interpret trace gas measurements at Mace Head, Ireland

被引:138
作者
Cape, JN
Methven, J
Hudson, LE
机构
[1] Inst Terr Ecol, Penicuik EH26 0QB, Midlothian, Scotland
[2] Univ Reading, Dept Meteorol, Reading RG6 6BB, Berks, England
[3] Univ Bristol, Sch Chem, Bristol BS8 1TE, Avon, England
基金
英国自然环境研究理事会;
关键词
back trajectory; clustering; chemical climatology; ozone; EASE;
D O I
10.1016/S1352-2310(00)00098-4
中图分类号
X [环境科学、安全科学];
学科分类号
08 ; 0830 ;
摘要
A first step in interpreting the wide variation in trace gas concentrations measured over time at a given site is to classify the data according to the prevailing weather conditions. In order to classify measurements made during two intensive field campaigns at Mace I-lead, on the west coast of Ireland, an objective method of assigning data to different weather types has been developed. Air-mass back trajectories calculated using winds from ECMWF analyses, arriving at the site in 1995-1997, were allocated to clusters based on a statistical analysis of the latitude, longitude and pressure of the trajectory at 12 h intervals over 5 days. The robustness of the analysis was assessed by using an ensemble of back trajectories calculated for four points around Mace Head. Separate analyses were made for each of the 3 pears, and for four 3-month periods. The use of these clusters in classifying ground-based ozone measurements at Mace Head is described, including the need to exclude data which have been influenced by local perturbations to the regional flow pattern, for example, by sea breezes. Even with a limited data set, based on 2 months of intensive field measurements in 1996 and 1997, there are statistically significant differences in ozone concentrations in air from the different clusters. The limitations of this type of analysis for classification and interpretation of ground-based chemistry measurements are discussed. (C) 2000 Elsevier Science Ltd. All rights reserved.
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页码:3651 / 3663
页数:13
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