A case study of atmospheric boundary layer features during winter over a tropical inland station — Kharagpur (22.32°N, 87.32°E)

Alappattu, Denny P.; Kunhikrishnan, P. K.; Aloysius, Marina; Mohan, Madan

doi:10.1007/s12040-009-0028-3

Cited by 18 publications

(9 citation statements)

References 20 publications

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“…In monsoon, the strong prevailing winds disperse the pollutants quickly and get them washed out by precipitation. In contrast to this, both winds and ABL depth are low over Indian subcontinent by which the pollutants get trapped during winter (Alappattu et al, 2009). The daytime average low O 3 mixing ratio (10.81 ± 3.84 ppbv) observed in July was mainly due to the intense south-west monsoon which washes out pollution over this location.…”

Section: Diurnal Variation and Rate Of Change Of O 3 During Differentmentioning

confidence: 77%

Observational Study of Surface O3, NOx, CH4 and Total NMHCs at Kannur, India

Nishanth

2014

Aerosol Air Qual. Res.

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This paper presents the results of measurements of the surface ozone (O 3 ), oxides of nitrogen (NO x ), methane (CH 4 ) and total non-methane hydrocarbons (TNMHCs) in a rural coastal location at Kannur (11.9°N, 75.4°E, 5 m asl), India from November 2009 to December 2011. The diurnal cycle for surface O 3 had a peak in the afternoon and declined during nighttime. The maximum and minimum mixing ratio of surface O 3 was observed in winter and monsoon seasons respectively. NO x concentration was high during mid-night to early morning and low during noontime. The diurnal variations of mixing ratios for NO x and O 3 were anti-correlated. Monthly average maximum (2.26 ± 0.44 ppmv) and minimum (0.43 ± 0.19 ppmv) CH 4 concentrations were observed in December and August respectively. The diurnal variations of CH 4 were similar to that of NO x . A CH 4 buildup was observed during early morning hours throughout the observational period. On an annual basis, the maximum, minimum and average total NMHCs were (25.45 ± 6.58 ppbv), (13.84 ± 4.31 ppbv), and (19.23 ± 5.56 ppbv) respectively at the observational site. Analysis of O 3 , NO, NO 2 , CH 4 and NMHC have been carried out and the correlation between O 3 and its precursors is discussed detailed. Further, the diurnal variation of O 3 over a free tropospheric region at Ooty, a hill station lying in the Western Ghats region of south India on clear sky days in February 2011 is also reported for a comparison.

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Section: Diurnal Variation and Rate Of Change Of O 3 During Differentmentioning

confidence: 77%

Observational Study of Surface O3, NOx, CH4 and Total NMHCs at Kannur, India

Nishanth

2014

Aerosol Air Qual. Res.

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“…Viswanadham and Pinaka Pani (1994) have reported alarmingly low morning V Cs over north India, the worst season being October followed by January. Alappattu et al (2009) studied the ABL features over Kharagpur (22.32 • N,87.32 • E) and found that in general, V C was low during the morning and evening hours and maximum during the early afternoon hours. The lowest V C values observed corresponded with significantly low wind speeds and high aerosol mass concentrations.…”

Section: Long-term Trends In Ventilation Coefficient (Vc)mentioning

confidence: 99%

“…Several researchers, viz., Padmanabhamurthy and Mandal (1979), Alappattu et al (2009) etc., have studied the assimilative capacity, dispersal capacity and pollution potential in terms of the variations in ventilation coefficients over different locations in India. However, they are limited to short periods of time.…”

Section: Introductionmentioning

confidence: 99%

Ventilation coefficient trends in the recent decades over four major Indian metropolitan cities

Iyer

Raj

2013

J Earth Syst Sci

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Indian metros, viz., Mumbai, Delhi, Kolkata and Chennai is analysed to study the trends and long term variations in ventilation coefficients and the consequences on the air quality due to these variations in the four metros. A decreasing trend in ventilation coefficient is observed in all the four metros during the 30 years period indicating increasing pollution potential and a degradation in the air quality over these urban centers. In Delhi, the ventilation coefficient decreased at the rate of 49 and 32 m 2 /s/year in the months of December and February, respectively during the 30-year period. In Mumbai, the average decrease in ventilation coefficient in winter months is about 15 m 2 /s/year whereas for Kolkata it is 14 and 17 m 2 /s/year in December and February, respectively. A decreasing trend in ventilation coefficient is observed in Chennai too although it is not significant. The decreasing ventilation coefficient increased the ground level pollution thereby deteriorating the air quality for the urban population. For Mumbai and Kolkata, decreasing mixing depths and decreasing wind speed contributed to the decreasing ventilation coefficient whereas for Delhi and Chennai decreasing wind speed was responsible for the decrease in ventilation coefficient. Further, the pollution potential was much higher in Delhi which is an inland station as compared to Mumbai, Kolkata and Chennai which are coastal stations under the influence of marine environment. Compared to Delhi, the pollution potential over these three metros was lower as the prevailing sea-breeze helped in the dispersal of pollutants thereby reducing their ground level concentration.

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“…This is relevant because there can be significant local contributions to the BC mass concentration. Moreover, the cause of the morning peak in the diurnal cycle is attributed to fumigation due to an increasing mixing layer (Devara and Raj, 1983;Alapattu et al, 2009;Mahalakshmi et al, 2011) which brings polluted air from aloft down to the surface. This is a reasonable assumption in a remote area with little to no local emissions.…”

Section: Diurnal Variations Of Bc Mass Concentrationmentioning

confidence: 99%

Potential Source Regions Contributing to Seasonal Variations of Black Carbon Aerosols over Anantapur in Southeast India

Reddy

Kumar

Balakrishnaiah

et al. 2012

Aerosol Air Qual. Res.

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Continuous measurements of black carbon (BC) mass concentration performed at Anantapur [14. 62°N, 77.65°E, 331 m asl], a suburban location in southeast India, using an Aethalometer from January to December, 2010, are analyzed and discussed here. The annual mean BC mass concentration ([BC]) was 3.03 ± 0.27 µg/m 3 for the above study period. The sharp morning (fumigation) peak occurs between 07:00 and 08:00 h almost an hour after the local sunrise while a broad evening (nocturnal) peak is at ~21:00 h with a minimum in noon hours (14:00-16:00 h). The seasonal mean values of [BC] are 5.05 ± 0.51 μg/m 3 in the winter, 3.77 ± 1.23, 1.55 ± 0.51, and 2.33 ± 0.82 µg/m 3 in the summer, monsoon and postmonsoon seasons, respectively. High BC values tend to occur when the wind is directed from the 180-225° sector, which may be well defined by the geographical location of the observation site. During the winter, the trajectory air mass pathways originated through north or central India with significant advection of continental aerosols arriving before the measurement region, results in an enhanced [BC]. Whereas in the monsoon season, the pristine marine air mass from the oceanic environment led to decrease in the concentration of BC. Comparison of monthly mean variations in AOD at 500 nm and black carbon aerosols is observed to be positive with poor correlation coefficient of 0.42. The ratio of BC/PM 2.5 varied from 1.3% to 7.2% with a mean value of 4.6% at Anantapur during the observation period and this ratio decreased with decreasing Ångström exponent (alpha).

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A case study of atmospheric boundary layer features during winter over a tropical inland station — Kharagpur (22.32°N, 87.32°E)

Cited by 18 publications

References 20 publications

Observational Study of Surface O3, NOx, CH4 and Total NMHCs at Kannur, India

Observational Study of Surface O3, NOx, CH4 and Total NMHCs at Kannur, India

Ventilation coefficient trends in the recent decades over four major Indian metropolitan cities

Potential Source Regions Contributing to Seasonal Variations of Black Carbon Aerosols over Anantapur in Southeast India

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