Doppler lidar observations over the Central Himalayan region: preliminary results

 

Authors

D V Phanikumar — Aryabhatta Research Institute of Observational Sciences
K K Shukla — Aryabhatta Research Institute of Observational Sciences
Manish Naja — Aryabhatta Research Institute of Observational Sciences
Narendra Singh — Aryabhatta Research Institute of Observational Sciences

Vimlesh Pant — Aryabhatta Research Institute of Observational Sciences
P Pant — Aryabhatta Research Institute of Observational Sciences

S. K. Satheesh — Indian Institute of Science

V. Rao Kotamarthi — Argonne National Laboratory

Category

Aerosol-Cloud-Radiation Interactions

Description

A Doppler lidar is installed at the Aryabhatta Research Institute of Observational-Sciences (ARIES), in Nainital, India, in the Central Himalayan region as a part of the Ganges Valley Aerosol Experiment (GVAX). Doppler lidars have an eye-safe, near-infrared laser source of wavelength 1.5 µm and have a high-speed scanner to achieve 30-m, 1.2 sec, and 3.8 cm/sec vertical, temporal, and Doppler velocity resolutions respectively. Doppler lidar is mainly used to study the boundary-layer dynamics and cloud microphysics over the Central Himalayan region and has been operational since June 2011. In this context, preliminary analysis is focused on studies related to clouds and boundary-layer evolution from June 2011 to October 2011. Some clear signatures of clouds are observed in most of the cases at different height regions, which was also evident from the ceilometer. The present study also reports diurnal variations in the boundary-layer evolution over this region for the first time. Some cases of extended structures above the boundary layer have been observed; those can be attributed to elevated aerosol layers during nighttime. These observations are also related to the presence of cloud presence at an altitude region of 4.5–7km. Short period modulations in the cloud layer are also observed with a periodicity of ~ 1 hour, which can either be attributed to short-period gravity waves or mountain waves generated due to the orography of the site. Our preliminary observations will be discussed in the light of current understanding of the boundary-layer dynamics.