Diurnal and seasonal variability of surface ozone and NO_xat a tropical coastal site: Association with mesoscale and synoptic meteorological conditions

Abstract

[1] Simultaneous measurements of near-surface ozone, NO x (NO + NO 2 ), and meteorological parameters were carried out at the tropical coastal location of Trivandrum (8.55°N, 77°E) in India from November 2007 to May 2009. The data have been used to investigate the diurnal and seasonal patterns of ozone and its precursor, NO x , and also the interdependence of these two chemical species. The diurnal pattern is found to be closely associated with the mesoscale circulation (sea breeze and land breeze) and the availability of NO x . The daytime peak in ozone extends until the onset of land breeze, which brings in NO x for titration of ozone. Near-surface ozone concentration reaches peak values during the postmonsoon or winter months and shows minima during the summer or monsoon season. The high ozone concentration during winter is due to the presence of northeasterly winds that transport precursor gases to the site. The daytime concentration of ozone is found to be directly linked to the nighttime level of NO x . The present analysis reveals that one molecule of NO x or NO 2 is responsible for the formation of about seven to nine molecules of ozone. A study of satellite-derived tropospheric ozone and total ozone has shown that tropospheric ozone contributes 8%-15% of total ozone over this site and near-surface ozone contributes 34%-83% of tropospheric ozone. The seasonal pattern of tropospheric column ozone is similar to that of tropospheric NO 2 .Citation: David, L. M., and P. R. Nair (2011), Diurnal and seasonal variability of surface ozone and NO x at a tropical coastal site: Association with mesoscale and synoptic meteorological conditions,

Measurements of ozone and its precursor nitrogen dioxide and crop yield losses due to cumulative ozone exposures over 40 ppb (AOT40) in rural coastal southern India

“…Debaje and Kakade (2009) reported the similar time lag from peak air temperature to peak O 3 concentration at continental rural site. Similarly, the maxima of O 3 concentration were always observed in the afternoon in all seasons similar to other coastal rural sites in southern India, a characteristic of rural site (Nair et al 2002;Debaje et al 2003;David and Nair 2011;Nishanth et al 2012). Figure 3a, b shows the annual average diurnal variation of NO 2 for 3 years 2007, 2008 and 2009, and diurnal variation in April and November.…”

“…The daytime maximum of O 3 concentration reaches greater than 48 ppb during the summer season at Thumba (Trivandrum) and Kannur sites (Nair et al 2002;David and Nair 2011;Nishanth et al 2012). Similarly, the average maximum O 3 concentrations greater than 40 ppb at Tranquebar was reported by Debaje et al (2003).…”

“…A few scattered O 3 measurements are available over the Indian southern coastal region (Nair et al 2002;Debaje et al 2003;David and Nair 2011;Nishanth et al 2012). The daytime maximum of O 3 concentration reaches greater than 48 ppb during the summer season at Thumba (Trivandrum) and Kannur sites (Nair et al 2002;David and Nair 2011;Nishanth et al 2012).…”

Ozone concentrations, flux and potential effect on yield during wheat growth in the Northwest-Shandong Plain of China

“…For a given location, the O 3 concentration variation was dependent on meteorological variables, such as global radiation, temperature, and wind speed (Dueñas et al, 2002;Cape, 2008;David and Nair, 2011). Because the variations of O 3 concentration and radiation were out-of-phase (Fig.…”

Environmental monitoring of surface ozone and other trace gases over different time scales: chemistry, transport and modeling

“…4). David and Nair (2011) reported that monsoonal air hailing from the marine sources is rich in water vapor content and can cause reduction of O 3 Concentration by involving OH Á radicals. These observations were supported by the air mass back trajectories simulated at the study site, which is discussed in the later part of the text.…”