Effect of cloud on atmospheric ozone formation over Kolkata (22°34′N, 88°24′E), India

Saha³

et al. 2012

J Earth Syst Sci

The paper presents the nature of annual cycles of tropospheric ozone, cloud occurrences, NO 2 , rainfall, SO 2 , SPM, CO, non-methane hydrocarbon and surface solar radiation for the period October 2004 to June 2009 over Alipore (22.52 • N, 88.33 • E), India. Annual cycle of low-level cloud occurrences depicts that the low-level cloud over Alipore had been noticed to occur for many days and nights, particularly from June to September. The low-level cloud occurrences were found in winter months and post-monsoon period. The effect of cloud occurrences on tropospheric ozone concentration has been critically analysed and explained. It has been observed that the concentration of ozone is oscillatory with cloud occurrences and has a slight linear decreasing trend with the increase of cloud occurrences and vice versa. The concentration of tropospheric ozone attained higher value at moderate cloud occurrences and comparatively lower value at both of the lower and higher cloud occurrences. The related possible chemical and physical explanation for role of cloud occurrences on tropospheric ozone has been offered.

Section: Discussionmentioning

confidence: 99%

Section: Study Of Cloud Chemistrymentioning

confidence: 99%

Effect of cloud occurrences on tropospheric ozone over, Alipore (22.52°N, 88.33°E), India

Jana¹,

Saha³

et al. 2012

J Earth Syst Sci

“…Total column ozone densities of different stations have been obtained from the website http://jwocky. gsfc.nasa.gov (Jana et al 2010a(Jana et al , 2010b. Monthly mean ozone densities have been calculated from daily average value of ozone in DU for the stations, namely, New Delhi and Halley Bay.…”

Section: Data and Analysismentioning

confidence: 99%

Yearly variation and annual cycle of total column ozone over New Delhi (29°N, 77°E), India and Halley Bay (76°S, 27°W), British Antarctic Survey Station and its effect on night airglow intensity of OH(8, 3) for the period 1979–2005

Jana¹,

Saha

2012

J Earth Syst Sci

A critical analysis made on the long-term monthly, seasonal, yearly variation and annual cycle of total column ozone (TCO) concentration at New Delhi (29 • N, 77 • E), India and Halley Bay (76 • S, 27 • W), a British Antarctic Service Station reveals more decline in yearly mean ozone concentration at Halley Bay than at New Delhi from 1979 to 2005. The nature of variations of monthly mean TCO during the months of August and September was the most identical with that of yearly mean ozone values at New Delhi and Halley Bay, respectively, for the same period. Annual cycles of TCO over these stations are completely different for the above period. The effect of O 3 depletion on night airglow emission of OH(8, 3) line at New Delhi and Halley Bay has been studied. Calculations based on chemical kinetics show that the airglow intensity of OH(8, 3) has also been affected due to the depletion of O 3 concentration. The yearly variations and annual cycle of intensities of OH(8, 3) line for the above two stations are depicted and compared. It has been shown that the rate of decrease of intensity of OH(8, 3) line was comparatively more at Halley Bay due to dramatic decrease of Antarctic O 3 concentration.

“…It is greatly influenced by predominant meteorological conditions (temperature, solar flux, wind speed and relative humidity). Several authors have studied the possible interaction of surface temperature and cloud cover on ozone concentration (Liu et al 2006 ; Voulgarakis et al 2009 ; Jana et al 2010 , 2011 ; Midya et al 2011 ; Ghosh et al 2015 ). O 3 concentration increases with an increase in solar flux and temperature (Gorai et al 2015 ).…”

Section: Introductionmentioning

confidence: 99%

Changes in tropospheric ozone concentration over Indo-Gangetic Plains: the role of meteorological parameters

Payra

Gupta

et al. 2022

Meteorol Atmos Phys

This study seeks to understand and quantify the changes in tropospheric ozone (O 3 ) in lower troposphere (LT), middle troposphere (MT) and upper middle troposphere (UMT) over the Indo-Gangetic Plains (IGPs), India during the COVID-19 lockdown 2020 with that of pre-lockdown 2019. The gridded datasets of ozone from the European Centre for Medium-range Weather Forecasts (ECMWF) reanalysis product, ERA5 in combination with statistical interpolated (IDWs) surface NO 2 observations, present a consistent picture and indicate a significant tropospheric ozone enhancement over IGP during COVID-19 lockdown restrictions in May 2020. The Paper also examines the influencing role of meteorological parameters on increasing ozone concentration. Over LT, an increase in O 3 concentration (23%) is observed and in MT to UMT an enhancement of about 9–18% in O 3 concentration have been seen during May 2020 with respect to May 2019. An investigation on causes of increasing ozone concentration (35–85 ppbv) from MT to UMT during May 2020 reveals that there was significant rise (by 1–6%) in low cloud cover (LCC). Notably, higher LCC increases the backscattering of upward solar radiation from the top of the atmosphere. A positive difference of 5–25 W/m 2 in upward solar radiation (USR) is observed across the entire study region. The result suggests that higher LCC significantly contributed to the enhanced USR. Thereby, resulting in higher photolysis rate that lead to an increase in mid tropospheric ozone concentration during May 2020. The results highlight the importance of LCC as an important pathway in ozone formation and aid in scientific understanding of it.