Articles | Volume 32, issue 2
Ann. Geophys., 32, 175–180, 2014
Ann. Geophys., 32, 175–180, 2014

ANGEO Communicates 21 Feb 2014

ANGEO Communicates | 21 Feb 2014

Signatures of Rossby wave modulations in aerosol optical depth over the central Himalayan region

D. V. Phanikumar1, K. Niranjan Kumar2, K. K. Shukla1,3, H. Joshi1, M. Venkat Ratnam4, M. Naja1, and K. Reddy5 D. V. Phanikumar et al.
  • 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.