Temporal variations in surface ozone at Thumba (8.6°N, 77°E)-a tropical coastal site in India

Nair, Prabha R.; Chand, D.; Lal, Shyam; Modh, K. S.; Naja, Manish; Parameswaran, K.; Ravindran, Sudha; Venkataramani, S.

doi:10.1016/s1352-2310(01)00527-1

Cited by 100 publications

(65 citation statements)

References 13 publications

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“…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.…”

Section: Methodssupporting

confidence: 72%

“…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).…”

Section: Introductionmentioning

confidence: 77%

“…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).…”

Section: Introductionmentioning

confidence: 99%

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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

Elampari

Debaje

Jeyakumar³

et al. 2013

J Atmos Chem

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Section: Methodssupporting

confidence: 72%

Section: Introductionmentioning

confidence: 77%

Section: Introductionmentioning

confidence: 99%

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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

Elampari

Debaje

Jeyakumar³

et al. 2013

J Atmos Chem

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“…These are reformed for 15 min each on a daily basis for an initial period of 1 year and then once very 3-4 weeks afterward. The minimum detection limit of the analyzer is about 1 ppbv and its response is about 10 s. Lal et al (1998Lal et al ( , 2000 and Nair et al (2002) have also been employed the same O 3 analyzer described above in their study. The absolute accuracy of these types of system is reported to be 5% (Kleinman et al 1994).…”

Section: Experimental Techniquementioning

confidence: 99%

Measurements of surface ozone at semi-arid site Anantapur (14.62°N, 77.65°E, 331 m asl) in India

et al. 2008

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In the present study, an attempt has been made to examine the governing photochemical processes of surface ozone (O 3 ) formation in rural site. For this purpose, measurements of surface ozone and selected meteorological parameters have been made at Anantapur (14.62°N, 77.65°E, 331 m asl), a semi-arid zone in India from January 2002 to December 2003. The annual average diurnal variation of O 3 shows maximum concentration 46 ppbv at noon and minimum 25 ppbv in the morning with 1σ standard deviation. The average seasonal variation of ozone mixing ratios are observed to be maximum (about 60 ppbv) during summer and minimum (about 22 ppbv) in the monsoon period. The monthly daytime and nighttime average surface ozone concentration shows a maximum (55±7 ppbv; 37±7.3 ppbv) in March and minimum (28±3.4 ppbv; 22±2.3 ppbv) in August during the study period. The monthly average high (low) O 3 48.9±7.7 ppbv (26.2± 3.5 ppbv) observed at noon in March (August) is due to the possible increase in precursor gas concentration by anthropogenic activity and the influence of meteorological parameters. The rate of increase of surface ozone is high (1.52 ppbv/h) in March and lower (0.40 ppbv/h) in July. The average rate of increase of O 3 from midnight to midday is 1 ppbv/h. Surface temperature is highest (43-44°C) during March and April months leading to higher photochemical production. On the other hand, relative humidity, which is higher during the rainy season, shows negative correlation with temperature and ozone mixing ratio. It can be seen that among the two parameters are measured, correlation of surface ozone with wind speed is better (R 2 =0.84) in compare with relative humidity (R 2 =0.66).

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“…Various possible mechanisms for the NSO enhancement are proposed, such as mountain valley wind system and vertical mixing (Sanchez et al, 2005), land and sea breeze (Nair et al, 2002), horizontal transport (Sousa et al, 2011), role of low-level jet (LLJ) associated with vertical mixing (Corsmeier et al, 1997;Klein et al, 2014), titration of urban ozone in the late afternoon/early evening followed by vertical mixing (Chan et al, 1998;Leung and Zhang, 2001), and transport due to vertical wind (W) from residual layer (Sanchez et al, 2007). Depending on various conditions such as the geographical location, boundary layer dynamics, topography, type of environment (urban, suburban and rural) and local weather conditions, any one of the proposed mechanisms was considered responsible for the NSO enhancement.…”

Section: Introductionmentioning

confidence: 99%

Nocturnal surface ozone enhancement over Portugal during winter: Influence of different atmospheric conditions

Kulkarni

Dasari

Sharma

et al. 2016

Atmospheric Environment

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h i g h l i g h t s4 distinct events of nocturnal surface ozone (NSO) enhancement were analyzed. WRF model was used to simulate the atmospheric conditions during NSO enhancement. Results show that different atmospheric mechanisms are responsible for each event.a r t i c l e i n f o a b s t r a c tFour distinct nocturnal surface ozone (NSO) enhancement events were observed, with NSO concentration exceeding 80mg/m 3 , at multiple ozone (O 3 ) monitoring stations (32 sites) in January, November and December between year 2000e2010, in Portugal. The reasonable explanation for the observed bimodal pattern of surface ozone with enhanced NSO concentration during nighttime has to be transport processes, as the surface ozone production ceases at nighttime. Simultaneous measurements of O 3 at multiple stations during the study period in Portugal suggest that horizontal advection alone cannot explain the observed NSO enhancement. Thus, detailed analysis of the atmospheric conditions, simulated with the Weather Research and Forecasting (WRF) model, were performed to evaluate the atmospheric mechanisms responsible for NSO enhancement in the region. Simulations revealed that each event occurred as a result of one or the combination of different atmospheric processes such as, passage of a cold front followed by a subsidence zone; passage of a moving surface trough, with associated strong horizontal wind speed and vertical shear; combination of vertical and horizontal transport at the synoptic scale; formation of a low level jet with associated vertical mixing below the jet stream. The study confirmed that large-scale flow pattern resulting in enhanced vertical mixing in the nocturnal boundary layer, plays a key role in the NSO enhancement events, which frequently occur over Portugal during winter months.

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Temporal variations in surface ozone at Thumba (8.6°N, 77°E)-a tropical coastal site in India

Cited by 100 publications

References 13 publications

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

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

Measurements of surface ozone at semi-arid site Anantapur (14.62°N, 77.65°E, 331 m asl) in India

Nocturnal surface ozone enhancement over Portugal during winter: Influence of different atmospheric conditions

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