A classification of CO2 concentrations based on a binary meteorological six variable system

作者：Perez Isidro A^*; Luisa Sanchez M; Angeles Garcia M; de Torre Beatriz

来源：Agricultural and Forest Meteorology, 2009, 149(10): 1686-1692.

DOI：10.1016/j.agrformet.2009.05.010

• RASS sodar
• Greenhouse gas
• CO2 evolution
• Low atmosphere meteorology
• Climate change

CO2 is one of the most important gases linked to climate change. However, its ambient concentrations in a clean atmosphere have scarcely been investigated. In this paper a close relationship between CO2 concentrations and meteorological variables was proposed to establish atmospheric conditions linked to high CO2 values. A detailed 3-year campaign was carried out in a rural area with a CO2 continuous analyser and a RASS soclar for meteorological variables. Daily and yearly CO2 cycles were obtained. In addition, semi-hourly medians and quartiles were fitted to straight lines during the night time and daily maxima and minima were parameterised by means of a second order cylindrical model. Six meteorological variables were considered: wind speed, wind direction and temperature at one level and differences between them at two levels. Intervals were proposed from the highest CO2 concentrations during the night to build up a binary system of 64 meteorological classes. Analysis of both CO2 medians and meteorological classes enabled simplification of the system to four groups. The first group, characterised by high temperatures and drainage flow, was associated with detrended median concentrations above 15 ppm. Two groups of moderate concentrations were linked to thermal inversions and no prevailing wind directions. The final group corresponded to low concentrations associated with less than three meteorological variables with values linked to high concentrations. Only high directional shear and low wind speed were relevant in this group. This 4-group system was successfully used with the whole dataset.

• 出版日期2009-10-1