Impact of Land-Sea Breeze and Rainfall on CO 2 Variations at a Coastal Station Mahesh P 1 , Sharma N 1 , Dadhwal VK 1 , Rao PVN 1 , Apparao BV 2 , Ghosh AK 2 , Mallikarjun K 1 and Ali MM 1 1 National Remote Sensing Centre, Balanagar, Hyderabad-500037, India 2 Met Facility, Satish Dhawan Space Centre, SHAR, Sriharikota, India * Corresponding author: Mahesh P, National Remote Sensing Centre, Balanagar, Hyderabad-500037, India, Tel: +91-40-23884231; E-mail: mahi952@gmail.com Rec date: April 17, 2014; Acc date: May 16, 2014; Pub date: Jun 20, 2014 Copyright: © 2014 Mahesh P, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Abstract Carbon dioxide (CO 2 ) observations collected at 5 min interval at Sriharikota during October 2011-January 2012 from the Vaisala GMP-343 sensor were averaged on an hourly basis. The baseline of atmospheric CO 2 during study period is 382 ppm. Minimum (maximum) mixing ratios were observed during the afternoon (night times) indicating the role of photosynthetic activity and the atmospheric boundary layer on this parameter. Sriharikota being a coastal station, the land and sea breezes mainly control CO 2 mixing ratios. The correlation between CO 2 and the wind speed is significantly less during sea breeze than during land breeze in October, compared to other months, where the correlations are more during sea breeze. The less correlation during sea breeze in October is due to the heavy rainfall in this month during daytime. Keywords: Carbon dioxide (CO 2 ) mixing ratios; Rainfall impact; Land and sea breezes Introduction Carbon dioxide (CO 2 ), one of the major Greenhouse Gases (GHG) in the atmosphere, plays a prominent role in climate change. The global mean concentration of CO 2 in 2005 was 379 ppm, leading to a Radiative Forcing (RF) of +1.66 [± 0. 17] W m-2 [1]. Recently, the CO 2 levels have gone up to a daily mean of 400 ppm in May 2013 at Mauna Loa, Hawaii [2]. Local meteorological and environmental factors control the CO 2 mixing ratios. During night times, temperature inversions prevent thorough mixing of the atmosphere. There is also an absence of photosynthetic activity consuming CO 2 . Due to these two processes, CO 2 mixing ratios increase at night. During the daytime due to increase in photosynthesis activity, CO 2 mixing ratio decreases [3]. Figure 1: Study location. Figure 2: Calibration curve. To understand the carbon cycle in the atmosphere, several surface CO 2 measuring network stations have been established across the county under National Carbon Project (NCP). NCP is a component of Geosphere Biosphere Programme (IGBP) of the Indian Space Research Organization (ISRO). Under this program terrestrial, ocean and atmospheric components of carbon balance are studied. Instruments are installed to measure the atmospheric CO 2 [3], flux measurements in forests [4] and in soil [5]. As a part of this program, GMP-343 is installed in 2011 at Sriharikota High Altitude Range (SHAR). Since this is a coastal station, we report the impact of the wind vector, particularly the land and sea breezes, on CO 2 variations from October 2011 to January 2012. While pure water has pH of 7.0, normal rain is slightly acidic with pH range from 5.0-5.6 [6] because of dissolving of CO 2 in water droplets forming a weak carbonic acid. The dissolution of CO 2 in rain drop depends upon the partial pressure of CO 2 and the atmospheric temperature. Since the study region influenced by North East (NE) monsoon, we also studied the impact of rainfall on CO 2 mixing ratios. Earth Science & Climatic Change Mahesh et al., J Earth Sci Clim Change 2014, 5:6 http://dx.doi.org/10.4172/2157-7617.1000201 Research Article Open Access J Earth Sci Clim Change ISSN:2157-7617 JESCC Volume 5 • Issue 6 • 1000201