Variations of trace gases over the Bay of Bengal during the summer monsoon

Journal of earth system science

Narendra Ojha^2¹  K Ravi Kumar^4,5²  Prabha R Nair^1³  Yogesh K Tiwari^3⁴  I A Girach^1⁵ 

[1] Department of Atmospheric Chemistry, Max Planck Institute for Chemistry, 55128 Mainz, Germany.^2;Department of Environmental Geochemical Cycle Research, JAMSTEC, Yokohama, Japan.^5;Indian Institute of Tropical Meteorology, Pune 411 008, India.^3;National Institute of Polar Research, Tachikawa, Japan.^4;Space Physics Laboratory, Vikram Sarabhai Space Centre, Thiruvananthapuram 695 022, India.^1

关键词: Ozone;    carbon monoxide;    methane;    monsoon;    Bay of Bengal;    MACC reanalysis;   

DOI  :  

学科分类：天文学(综合)

来源: Indian Academy of Sciences

【 摘 要 】

In situ measurements of near-surface ozone (O₃), carbon monoxide (CO), and methane (CH₄) were carried out over the Bay of Bengal (BoB) as a part of the Continental Tropical Convergence Zone (CTCZ) campaign during the summer monsoon season of 2009. O₃, CO and CH₄ mixing ratios varied in the ranges of 8–54 ppbv, 50–200 ppbv and 1.57–2.15 ppmv, respectively during 16 July–17 August 2009. The spatial distribution of mean tropospheric O₃ from satellite retrievals is found to be similar to that in surfaceO₃ observations, with higher levels over coastal and northern BoB as compared to central BoB. The comparison of in situ measurements with the Monitoring Atmospheric Composition & Climate (MACC) global reanalysis shows that MACC simulations reproduce the observations with small mean biases of1.6 ppbv, –2.6 ppbv and 0.07 ppmv for O₃, CO and CH4, respectively. The analysis of diurnal variation of O₃ based on observations and the simulations from Weather Research and Forecasting coupled with Chemistry (WRF-Chem) at a stationary point over the BoB did not show a net photochemical build up during daytime. Satellite retrievals show limitations in capturing CH₄ variations as measured by in situ sample analysis highlighting the need of more shipborne in situ measurements of trace gases over thisregion during monsoon.

【 授权许可】

CC BY