Digital image processing of Remote Sensing data for water quality studies

Remotely sensed data has been found useful in various aspects of hydrology like sedimentation, water quality watershed management, flood and drought monitoring, ground water resources evaluation etc. With the fast development of computer applications to image processing and availability of low cost image processing systems, digital image processing methods supplemented by visual interp etation aids will be useful for effective utilization of Remote Sensing data. Application of various digital image processing along with using a low cost image processing system for detailed study of water quality parameters is discussed. Studies have been conducted in a sample revervoir to obtain suitable digital image processing techniques for achieving better visual separability within the reservoir water. An overview of semiquantification of sediment concentration in the reservoir water using computer aided processing methods is presented in this paper.     

Studies on forest fires using dmsp ols data

Studies related to forest fires are important in the context of trace gas emissions associated with such events. Much of the polar orbiting satellites due to their repetitive cycle have limitation in observing such events and in tropics due to cloud cover, the chance of getting cloud free image during day time becomes difficult. In order to explore the possibilities of using DMSP OLS night time data for monitoring such event, the present study has been under taken in Central Himalayan region of India where extensive fire event has been reported in May/June, 1995. The results of the study suggests the possibility of monitoring such events using DMSP OLS night time data.     

Vegetation discrimination using irs-p3 wifs temporal dataset - a case study from rampa forests, eastern ghats, a.p.

Multitemporal data sets from coarse resolution sensors of Indian Remote Sensing Satellites provides an opportunity to classify various forest types using their phenological attributes reflected in temporal NDVI profiles. The present study attempts to classify various vegetation classes using time integrated NDVI (T-NDVI) values derived from IRS-P3 WiFS data. The algorithm explores the differential characteristics in T-NDVI values of different features and the results suggest the possible use of the methodology for forest type classification.     

Characterization of aerosol optical depth, aerosol mass concentration, UV irradiance and black carbon aerosols over Indo-Gangetic plains, India, during fog period

Every year during winter months (December?CJanuary) fog formation over Indo-Gangetic plains (IGP) of Indian region is believed to create numerous hazards. The present study addresses variations in aerosol optical properties, aerosol mass concentration and their impact on solar irradiance for pre-during-post fog conditions of December 2004 over IGP, India. Continuous measurements on aerosol optical depth (AOD), total aerosol mass concentration, black carbon (BC) aerosols, UV_ery and UVA were carried out for pre, during and post fog periods over study site of Allahabad, India, during December 2004 as a part of Aerosol Land Campaign-II conducted by Indian Space Research Organization (ISRO). High aerosol mass concentrations were observed during fog and post-fog periods. Accumulation mode particle loading was found to be high during pre-fog period and coarse mode particle loading was observed to be high during fog and post-fog periods. Considerable reduction in UV_ery and UVA irradiance was observed during fog period compared with pre and post-fog periods. Analysis of NOAA-HYSPLIT model runs suggested that enhanced biomass burning episodes down-wind to the study area increased the concentration of AOD and BC.     

Spectral characteristics of sediment laden water

A Laboratory experiment has been conducted to establish relation between absolute percent reflectance as measured by Exotech spectro-radiometer compatible to LANDSAT MSS and corresponding known sediment concentrations in a specially designed laboratory sedimentation tank under known illumination conditions. Sediment samples are collected from the bed load deposits of JAYAKWADI reservoir by using a bed load sampler and are analysed in the laboratory for their particle size distribution. Sediment concentrations in the range of 50–1100 mg/l are used in the experiment. A multiple linear regression equation has been developed between absolute percent reflectance and sediment concentration. The results indicate that diffused absolute reflectance from water volume increases with increased sediment concentration and separability between bands is higher at higher concentrations. Exotech band 2 provides significant response from suspended sediment concentrations. There is almost one to one correspondence between predicted (from the model) suspended sediment concentrations and actual concentrations with a coefficient of determination of 0.962 and a standard eror of estimate of 56.47 mg/l. This may be due to the fact that most of the noise sources are nearly eliminated in the controlled laboratory experiment.     

Effect of synoptic meteorological conditions on aerosol properties over urban environment: A study over tropical urban region of Hyderabad,India

Aerosol particle size distribution and chemical properties are important in studies related to human health and climate. The present study describes an analysis of aerosol mass loading, Aerosol Optical Depth (AOD), black carbon aerosol mass concentration and carbon monoxide over tropical urban region of Hyderabad, India, during March 2006, coinciding with active forest fires season over India. Aerosol optical depth, particulate matter mass loading and carbon monoxide were observed to be high on days with air mass coming from north of the study area. Spatial occurrence of forest fires was analysed using MODIS daytime data and DMSP-OLS nighttime data sets. Aerosol optical depth measured using Microtops-II sunphotometer correlated well with MODIS derived AOD values. Results of the study suggested that synoptic meteorological conditions play an important role in the observed aerosol properties over the study area during the forest fire season.     

Forest fires monitoring using envisat-aatsr data

Forests over Indian region are fire prone during summer season and effective means for monitoring such events is important. Satellite data with its repetitive and wide area coverage provides data sets required for monitoring such events. The advances in sensor technology and multi-satellite systems have improved capability for monitoring such events. The present study addresses forest fires monitoring using night time data sets of ENVISAT-AATSR data over Indian Region. The results of the study indicated that region specific algorithms are required for forest fire detection as soils in tropical regions have higher temperatures during night time.     

Studies on biodiversity using semivariogram approach from IRS-IC LISS-III data

Present study attempts to utilise the spatial information from IRS-IC LISS-III satellite data, through, tie use of Semivartogram apprqatfu for analyzing the overstorey. diversity In forest stands, Semivariance has been calculated for all the pixels in I5x15 pixel window for each of the forest stand using digital numbers from near infrared channel Variation in semivariance has been correlated to stand density and species composition. Analysis of averaged semivariance for overall diversity of forest stands suggested, decreasing semi variance in the order, mixed dry (feciduous forests, mixed scrub forests followed by dry deciduous forest Semivariance has been found to be highly Correlated to tree density (R² = 0.96) suggesting semivariograms as one of the measures for studies on tree density, canapy cover and diversity patterns.     

Long-range transport of aerosols from agriculture crop residue burning in Indo-Gangetic Plains—A study using LIDAR,ground measurements and satellite data

Agriculture crop residue burning in tropics is an important source of atmospheric aerosols and monitoring their long-range transport is an important element in climate change studies. Synchronous measurements using micro-pulsed lidar, MICROTOPS-II sun photometer, multi-filter rotating shadow band radiometer (MFRSR) on aerosol optical depth and ground reaching solar irradiance were carried at an urban location in central region of India. Aerosol backscatter profiles obtained from micro-pulse lidar showed elevated aerosol layers up to ～3 km on certain days during October 2007. Satellite data observations on aerosol properties suggested transport of particles from agriculture crop residue burning in Indo-Gangetic Plains over large regions. Radiative forcing of aerosols estimated from SBDART model with input information on aerosol chemical properties, aerosol optical depth and single scattering albedo and broadband solar irradiance measurements using MFRSR showed good correlation (R=0.98).