In analysis are explained.In Chapter 3, we

In the present thesis, we have studied the atmospheric aerosols over the Indo Gangetic-Basin (IGB) using satellite and ground-based measurements and model simulations. The main focus of the thesis was to study the physical and chemical properties, dynamics and long-term effect of atmospheric aerosols over the IGB. The short and long-term trends of aerosols, correlation studies of satellite data with the ground observed data, physical and radiative properties of aerosols during specific events like dust storm and biomass burning in the IGB region are discussed. Chemical characterization of aerosol samples from the ground station and the effect of aerosols and meteorological parameters on lightning, rain and NDVI over IGB are also studied. The thesis has seven chapters.Chapter 1 briefly deals with the background introduction of Aerosols, basic properties and their impact on climate. In addition, relevant previous work done is also summarized.In Chapter 2, we have described the data set and methodology used for ground and satellite-based measurements like AERONET Sunphotometer and sky radiometers, MICROTOPS-II Sun photometers, High Volume Sampler and Terra/Aqua MODIS data, CALIPSO data, TRMM rainfall & LIS lightning flash data. The methodology used in Radiative Transfer Modeling SBDART model, NCEP/NCAR reanalysis & HYSPLIT Air-mass back/forward trajectories analysis are explained.In Chapter 3, we have studied the general trend of aerosols over India as a North-South profile, correlation of AERONET AOD (Aerosol Optical Depth) with MODIS and MISR derived AOD and seasonal variability of AOD over the IGB. The study of aerosol optical properties, its distributions, and seasonal variations shows IGB to be one of the most aerosol loaded regions in South Asia. This is also confirmed by the North-South profile of aerosols. Further analysis showed that every year during the post-monsoon season (October–November), crop residues have been burned over Northwestern India (the state of Punjab) by the farmers. MODIS observations revealed a strong west-to-east AOD gradient over the IGB during the peak burning period (15 October to 15 November) of 2012. The northwesterly wind helps in spreading of smoke plumes along the IGB.Chapter 4 deals with the study of major dust storms which occurred over the IGB during pre-monsoon of 2010. The change in aerosol optical and radiative properties during major dust storms over the IGB during pre-monsoon of 2010 showed many interesting results. Radiative forcing is also calculated during the dusty and non-dusty days.The aerosol characterization and their identification over Varanasi city is described in Chapter 5. The chemical and physical properties of aerosol samples in polluted (city) and clean (BHU Campus) area are studied using SEM-EDX and Ion chromatograph techniques. The analysis showed the BHU campus to be relatively clean area and different parts of Varanasi city to be quite polluted. The study showed the alarmingly high concentration of aerosols, some of which are hazardous to human health.Further, a long-term study of the effect of aerosols and meteorological parameters on lightning, rain, and NDVI over four equal-area regions (R1 to R4) in IGB have been studied in Chapter 6. It was observed that lightning flashes were maximum in R1 region although surface temperature, CAPE, water vapor and cloud cover fraction responsible for lightning were minimum in this region. This shows that orographic features may play significant role in convection process.Finally, a summary of the work done, conclusion and the scope for future works are given in Chapter 7.