ABSTRACT
The earth's environment is constantly changing. The scientific evidence indicates that these changes are result of a complex interplay among several natural and human-related systems. Therefore, in recent times, concern has grown about global change—which is related to natural and anthropogenic alteration of the Earth's environment. Among them, the important issues of concern are global greenhouse warming, urban and regional atmospheric pollution, regional increases in tropospheric ozone, the decrease in stratospheric ozone in general and the ozone hole over Antarctica in particular, acid rain, and so on. In Antarctica, contamination sources are distant, and the air is very well mixed, extremely clean, and far removed from spatial and seasonal changes. It is truly the background air of the planet compared to measurements made elsewhere around the globe. Antarctica holds the most efficiently coupled radiation-ice-air-ocean interactive system, which sustains primitive life forms over the continent. In this coupled system, atmosphere plays a vital role in the transfer of thermal energy and the momentum from one system to another, resulting in sustaining the Antarctic continent and its environment over the past millions of years. However, despite its sustenance, the Antarctic environment is influenced by global changes, which need to be evaluated to study the future of Earth's environment. Therefore, special conditions prevailing over Antarctica make it an ideal site for the monitoring of various atmospheric parameters. National Physical Laboratory (NPL), New Delhi, has been participating in the Indian Antarctic Expeditions right from its inception in 1981 and is carrying out scientific investigations related to the Antarctic atmospheric environment. The major experiments set up by NPL over the years at Maitri include VLF; riometer; microbarograph; weather station to monitor meteorological parameters; 28-meter-high tower to install sensors for meteorological parameter measurement at different heights; collection of air samples for gaseous concentration; high-volume air sampler; SODAR for planetary boundary layer studies; laser heterodyne and mm wave radio spectrometer to get ozone profiles; liquid nitrogen plant to produce liquid nitrogen needed for the laser heterodyne system; sun photometer; UV biometer; MICROTOP to estimate column ozone, water vapor, aerosol optical depth, and so on; gas chromatogram for regular monitoring of greenhouse gases such as CO2, CH4, and so on; and NDIR CO analyzer for around-the-clock monitoring of CO. In the present chapter, the salient features of various experiments conducted by NPL and results obtained are discussed in detail.
