Signatures of Rossby wave modulations in aerosol optical depth over the central Himalayan region
- 1Aryabhatta Research Institute of observational Sciences, Nainital, India
- 2Masdar Institute of Science and Technology, Abu Dhabi, United Arab Emirates
- 3Pt. Ravishankar Shukla University, Raipur, Chhatisgarh, India
- 4National Atmospheric Research Laboratory, Gadanki, India
- 5Department of Physics, Yogi Vemana University, Kadapa, India
Abstract. Long-period modulations are shown in aerosol optical depth measured by the Microtops II Sun photometer over a high-altitude site the central Himalayan region (Nainital, 29.4° N, 79.5° E, 1958 m a.m.s.l.) for the first time. Fourier analysis of aerosol optical depth showed dominant 25–45 day oscillations observed in MODerate-resolution Imaging Spectro radiometer data. Further, a Hovmiller diagram showed westward (northward) propagation at a different longitude (latitude), confirming that the modulations are associated with Rossby waves. It is also shown that the Rossby wave amplitude causes an additional warming of 4.16 ± 0.98 W m−2 over the observational site. Hence, the present study illustrates the importance of wave-induced aerosol dynamics and the corresponding radiative effects.