LIDAR

Projects >> LIDAR

Nainital is geographically located in 'free tropospheric' zone and is reasonably sparse from the point of view of major pollution, making the site quite suitable to study aerosol loading and climate variability. In lower atmosphere aerosols and trace gases are considered to be the most important entities in the radiation budget and climatic variability. Such unique location being at a high altitude (~2 km amsl) which is a natural advantage of Nainital, demands for regular and systematic observations of atmospheric parameters, to understand the various atmospheric processes.


The study of aerosols at ARIES was initiated during January, 2002 when a Multi-wavelength solar Radiometer (MWR) was installed at Manora Peak, Nainital, under ISRO's Geosphere-Biosphere-Program (ISRO-GBP) for evaluation the spectral aerosols optical depths. In order to study the aerosol's characteristics, the augmentation plan of various other instruments was undertaken later on. The important parameters of aerosols, which are measured for their characterization point of view, are Aerosol optical depths, Mass and number size distributions. BC mass concentration, Number-size distribution of sub and super-micron aerosols, TSPM, Total columnar Ozone, Coulmanar water vapour, met-data etc. These parameters are measured at ARIES using MWR, Microtops-II, ozonometer and sunphotometer, GRIMM aerosol spectrometer (optical particle counter (OPC)), Aethalometer (7-channel), High Volume air Sampler (HVS) and Automatic weather station etc.


Besides all these activities a portable LIDAR system, based on micro pulse LIDAR (MPL) technology was installed in a temperature controlled room at ARIES, Manora Peak, Nainital, in May 2006. This LIDAR has designed and developed at National Atmospheric Research laboratory (NARL), Gadanki, Tirupati. Since, Manora Peak is located geographically in free tropospheric zone, the site is conducive for evaluating the aerosol loading effects on the atmosphere due to the aerosol transportation from nearby polluted valley regions and also the long range aerosol transportation from far off regions to this height, apparently discernible during the major dust storms. In this perspective the LIDAR observations of tropospheric aerosols are being carried out for the first time, in the central Himalayan region at an altitude of ~2.0 km above mean sea level with a range resolution of 0.03 km. During the observations the LIDAR system collects the backscattered laser returns from the atmospheric aerosol and high altitude clouds.