Publications

Panicker, AS; Shaima, N (2021). Aerosol Oscillations Over Different Emission Regions in India. PURE AND APPLIED GEOPHYSICS, 178(10), 4097-4105.

Abstract
Potential oscillations in aerosol optical depth (AOD) were studied over six different regions, which were identified as major sources of aerosol emissions over India. Wavelet analysis was carried out to extract the major periodicities in aerosol loading along with the stratospheric mean zonal wind (U) at three different levels (10, 50 and 925 hPa levels) over different Indian regions. Periodicities of 12-24 months (quasi-biennial oscillation, QBO), and 24-48 months (quasi-triennial oscillation, QTO) were found to be the major oscillations in AOD during 2000-2019 over most of the selected regions. A 24-48-month QTO was observed over all the regions except region R4 (Southern India), where a periodicity of 12-24 months was dominant in AOD oscillations. Over regions R3 (Indo-Gangetic Plain) and R5 (Western India), a weak QBO was observed in addition to QTO. A weak annual oscillation (6-12 months) was also observed over R3. All the six regions showed a strong 24-48-month oscillation in zonal wind U for the same period (2000-2019). The occurrence of QTO in five regions (the exception being region R4) was found to be strongly linked with the stratospheric U wind oscillation. The co-occurrence of the same periodicities (24-48 months) in AOD and U wind suggests that the oscillations of U wind leads to the oscillations of aerosols over these regions.

DOI:
10.1007/s00024-021-02833-9

ISSN:
0033-4553