Impact of ENSO on variability of AIRS retrieved CO2 over India.

This study investigates the impact of ENSO on the CO 2 variability over the Indian subcontinent for the period 2003–2011 based on the relationships between NINO indices derived from the sea surface temperature (SST) and AIRS-retrieved mid-tropospheric CO 2 concentrations. The NINO4 region exhibits positive influence on the variability of CO 2 almost during the entire year except for the post-monsoon/winter months (October through December; OND). Significant positive relationship (correlation coefficient r = +0.68) between NINO4 index and CO 2 levels is observed for the month of June, while negative relationship (r = −0.73) for the month of October, and the negative relationship tends to continue till November with decreasing magnitudes (r = −0.41). The spatial distribution of mid-tropospheric CO 2 concentrations during El Niño and La Niña periods also indicate large-scale impact over the Indian subcontinent with positive (negative) anomalies of about 1–2 ppm during El Niño (La Niña). [ABSTRACT FROM AUTHOR]