Direct and Remote Sensing Methods for Chemical Pollution Studies

摘要

Efficient observational methods and long-term monitoring of the pollutant levels are of great interest in understanding the source emissions, ambient air quality, atmospheric chemical transformation and long-term transport and removal of aerosol pollutants (wet and dry) and the associated feedback processes. Most quantitative determination of air pollutants such as aerosols and gases have until now been made by point monitors/direct/conventional techniques, which provide reliable information at a specific location. Vertical profiling of any parameter using point monitors involves tedious procedures and analysis of such data is laborious and time consuming. Much more representative values can be obtained with remote sensing techniques, which also provide unique means to study the dynamical, physical and radiative processes influencing directly or indirectly the air quality. Remote sensing schemes, on the other hand, have made considerable progress in the recent past. Of the latest optical remote sensing techniques, the active methods such as lidar and passive methods such as solar radiometry have been recognized to be powerful and versatile tools for environmental diagnostics. Satellites provide an unparalleled capability to monitor atmospheric constituents from higher altitudes on a global scale for longer time periods. The recent satellite-based active (lidar) and hyper-spectral passive sensors extended this capability further.