Ground and satellite based measurements show significant loading of atmospheric aerosols over the highly populated Indo-Gangetic Plains with implications to both air quality and regional climate. Recent studies have found varying trends in aerosol loading over this region during different seasons. However, most of these trends were associated or linked to changes in the strength of emission sources of both natural and anthropogenic origin. In this study, using data from multiple satellites (MODIS and MISR) and reanalysis (ECMWF, NCEP) products, we show that emission characteristics over the West or North-western part of India have significant impact on aerosol loading over the IGP irrespective of the seasons. Though it is known that variability in a combination of meteorological parameters impact aerosol loading conditions, we show that it is possible to explain them by using just the wind speed as a proxy. This shows that even slight changes to emission over Northwestern part of the Indian region may have significant impact on aerosol loading conditions over IGP with implications to air quality and regional climate.
{"title":"Towards understanding the variability of aerosol characteristics over the Indo-Gangetic Plain","authors":"V. Vinoj, S. K. Pandey","doi":"10.1117/12.2223315","DOIUrl":"https://doi.org/10.1117/12.2223315","url":null,"abstract":"Ground and satellite based measurements show significant loading of atmospheric aerosols over the highly populated Indo-Gangetic Plains with implications to both air quality and regional climate. Recent studies have found varying trends in aerosol loading over this region during different seasons. However, most of these trends were associated or linked to changes in the strength of emission sources of both natural and anthropogenic origin. In this study, using data from multiple satellites (MODIS and MISR) and reanalysis (ECMWF, NCEP) products, we show that emission characteristics over the West or North-western part of India have significant impact on aerosol loading over the IGP irrespective of the seasons. Though it is known that variability in a combination of meteorological parameters impact aerosol loading conditions, we show that it is possible to explain them by using just the wind speed as a proxy. This shows that even slight changes to emission over Northwestern part of the Indian region may have significant impact on aerosol loading conditions over IGP with implications to air quality and regional climate.","PeriodicalId":165733,"journal":{"name":"SPIE Asia-Pacific Remote Sensing","volume":"123 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130842801","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Impact of aerosols on the Indian summer monsoon (ISM) variability is well documented; however there are limited studies which have quantified the role of aerosols in modifying the amount of rainfall. To address this research problem, we make use of the remotely sensed data set of precipitation and aerosols from different observations. In the present study remotely sensed precipitation data set has been utilised to define contrasting monsoon conditions over the Himalayan region. As per the classical definition, active and break spells are defined over the central part of the Indian land region, and during the break spells over the central Indian region, the Himalayan region receives substantial amount of rainfall. It is found that accumulation of more dust over the Uttarakhand region significantly (negative correlation with rainfall; significant at 5% significance level) suppresses the rainfall during break spells. We propose that the substantial aerosol loading and its associated dynamical feedback over the Himalayan foothills may have considerable impact on the amount of rainfall over the mountainous regions of the Indian subcontinent. Results presented in this paper are supported by the statistically robust significance test and would be useful to develop the understanding of the role of aerosols in modulating the rainfall intensity during the summer monsoon season.
{"title":"Aerosols and contrasting monsoon conditions over the Himalayan region","authors":"C. Singh, D. Ganguly, S. K. Dash","doi":"10.1117/12.2223525","DOIUrl":"https://doi.org/10.1117/12.2223525","url":null,"abstract":"Impact of aerosols on the Indian summer monsoon (ISM) variability is well documented; however there are limited studies which have quantified the role of aerosols in modifying the amount of rainfall. To address this research problem, we make use of the remotely sensed data set of precipitation and aerosols from different observations. In the present study remotely sensed precipitation data set has been utilised to define contrasting monsoon conditions over the Himalayan region. As per the classical definition, active and break spells are defined over the central part of the Indian land region, and during the break spells over the central Indian region, the Himalayan region receives substantial amount of rainfall. It is found that accumulation of more dust over the Uttarakhand region significantly (negative correlation with rainfall; significant at 5% significance level) suppresses the rainfall during break spells. We propose that the substantial aerosol loading and its associated dynamical feedback over the Himalayan foothills may have considerable impact on the amount of rainfall over the mountainous regions of the Indian subcontinent. Results presented in this paper are supported by the statistically robust significance test and would be useful to develop the understanding of the role of aerosols in modulating the rainfall intensity during the summer monsoon season.","PeriodicalId":165733,"journal":{"name":"SPIE Asia-Pacific Remote Sensing","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127677967","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The climate of India is dominated by monsoon systems. The remotely sensed estimates obtained from the Tropical Rainfall Measuring Mission (TRMM) are used to examine the most of the Indian monsoon systems. This study deals with the diurnal and spatial variation of precipitation over the Indian region. The precipitation data from TRMM Multi-satellite Precipitation Analysis (TMPA), blended from a variety of sources (including rain gauges over land) and having both daily and 3- hourly output are being used for evaluation of the Numerical Weather Prediction models Basu (2007) of National Centre for Medium Range Weather Forecasting. The precipitation obtained from TRMM 3B42 for this study period has a spatial resolution of 0.25º X 0.25º latitude-longitude. The 3-hourly averaged values are centered at the middle of each 3 hr period. South Asian regions are dominated by seasonal climatic fluctuations and the major rainy season is the southwest monsoon season. In addition to the seasonal fluctuations, Indian summer monsoon is modulated by diurnal fluctuations; nature of diurnal variation of rainfall varies from place to place and depends upon the locations, topography of the region. Diurnal variation of rain-rate, frequency of rain, conditional rain rate, and maximum and minimum rain occurrence is studied. Over Indian tropical region, maximum rainfall over land and Bay of Bengal regions is observed during the late-afternoon and early-morning period, respectively. Drizzle or less rainfall occur frequently in the morning over most land areas, whereas convective activity occurs during the afternoon. The model predicted diurnal cycle of precipitation peaks too early (by ~3h) and the amplitude is too strong over Indian land region and tropical ocean region.
{"title":"Diurnal and spatial variation of remotely sensed precipitation over Indian region","authors":"D. Rajan, G. Iyengar, A. Mitra","doi":"10.1117/12.2223852","DOIUrl":"https://doi.org/10.1117/12.2223852","url":null,"abstract":"The climate of India is dominated by monsoon systems. The remotely sensed estimates obtained from the Tropical Rainfall Measuring Mission (TRMM) are used to examine the most of the Indian monsoon systems. This study deals with the diurnal and spatial variation of precipitation over the Indian region. The precipitation data from TRMM Multi-satellite Precipitation Analysis (TMPA), blended from a variety of sources (including rain gauges over land) and having both daily and 3- hourly output are being used for evaluation of the Numerical Weather Prediction models Basu (2007) of National Centre for Medium Range Weather Forecasting. The precipitation obtained from TRMM 3B42 for this study period has a spatial resolution of 0.25º X 0.25º latitude-longitude. The 3-hourly averaged values are centered at the middle of each 3 hr period. South Asian regions are dominated by seasonal climatic fluctuations and the major rainy season is the southwest monsoon season. In addition to the seasonal fluctuations, Indian summer monsoon is modulated by diurnal fluctuations; nature of diurnal variation of rainfall varies from place to place and depends upon the locations, topography of the region. Diurnal variation of rain-rate, frequency of rain, conditional rain rate, and maximum and minimum rain occurrence is studied. Over Indian tropical region, maximum rainfall over land and Bay of Bengal regions is observed during the late-afternoon and early-morning period, respectively. Drizzle or less rainfall occur frequently in the morning over most land areas, whereas convective activity occurs during the afternoon. The model predicted diurnal cycle of precipitation peaks too early (by ~3h) and the amplitude is too strong over Indian land region and tropical ocean region.","PeriodicalId":165733,"journal":{"name":"SPIE Asia-Pacific Remote Sensing","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130012371","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Haiml, D. Eich, W. Fick, H. Figgemeier, S. Hanna, M. Mahlein, W. Schirmacher, R. Thöt
Cryogenically cooled HgCdTe (MCT) quantum detectors are unequalled for applications requiring high imaging as well as high radiometric performance in the infrared spectral range. Compared with other technologies, they provide several advantages, such as the highest quantum efficiency, lower power dissipation compared to photoconductive devices, and fast response times, hence outperforming micro-bolometer arrays. AIM will present its latest results on n-on-p as well as p-on-n low dark current planar MCT photodiode focal plane detector arrays at cut-off wavelengths >11 μm at 80 K. Dark current densities below the Rule’07 have been demonstrated for n-on-p devices. Slightly higher dark current densities and excellent cosmetics with very low cluster and point defect densities have been demonstrated for p-on-n devices.
{"title":"Low dark current LWIR HgCdTe focal plane arrays at AIM","authors":"M. Haiml, D. Eich, W. Fick, H. Figgemeier, S. Hanna, M. Mahlein, W. Schirmacher, R. Thöt","doi":"10.1117/12.2229027","DOIUrl":"https://doi.org/10.1117/12.2229027","url":null,"abstract":"Cryogenically cooled HgCdTe (MCT) quantum detectors are unequalled for applications requiring high imaging as well as high radiometric performance in the infrared spectral range. Compared with other technologies, they provide several advantages, such as the highest quantum efficiency, lower power dissipation compared to photoconductive devices, and fast response times, hence outperforming micro-bolometer arrays. AIM will present its latest results on n-on-p as well as p-on-n low dark current planar MCT photodiode focal plane detector arrays at cut-off wavelengths >11 μm at 80 K. Dark current densities below the Rule’07 have been demonstrated for n-on-p devices. Slightly higher dark current densities and excellent cosmetics with very low cluster and point defect densities have been demonstrated for p-on-n devices.","PeriodicalId":165733,"journal":{"name":"SPIE Asia-Pacific Remote Sensing","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126138075","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Aerosols are tiny suspended particle in the atmosphere with high variability in time and space, play a major role in modulating the cloud properties and thereby precipitation. To understand the aerosol induced Invigoration effect predictors like aerosol optical depth, cloud optical depth, cloud top temperature, cloud effective radii, ice water path, retrieved from the Moderate resolution Imaging Spectroradiometer (MODIS) level-3 aqua satellite data were analysed for pre monsoon April-May and post monsoon October-November months over the Indian subcontinent 8 ° N to 33° N, 65 °E to 100 °E during the period 2003–2013. Apart from the above data, mesoscale dynamical parameters such as vertical wind shear of horizontal wind, relative humidity, were also considered to understand their role in invigoration. Case studies have been carried out for the regions having heavy rainfall events & minimal rainfall events during high Aerosol optical depths occasions respectively. Analysis revealed that the heavy rainfall which occurred in this region with higher optical depths might be due to invigoration effect of aerosols wherein the dynamical as well as thermodynamical parameters were also found favourable. Minimal rainfall events were also observed most probably due to the suppression of rain formation/delay in precipitation due to high amount of aerosol concentration in these regions. Prominent 36 such cases were studied all over India during Pre & Post monsoon months.
{"title":"Aerosol-cloud interactions: effect on precipitation","authors":"J. Takle, R. Maheskumar","doi":"10.1117/12.2222753","DOIUrl":"https://doi.org/10.1117/12.2222753","url":null,"abstract":"Aerosols are tiny suspended particle in the atmosphere with high variability in time and space, play a major role in modulating the cloud properties and thereby precipitation. To understand the aerosol induced Invigoration effect predictors like aerosol optical depth, cloud optical depth, cloud top temperature, cloud effective radii, ice water path, retrieved from the Moderate resolution Imaging Spectroradiometer (MODIS) level-3 aqua satellite data were analysed for pre monsoon April-May and post monsoon October-November months over the Indian subcontinent 8 ° N to 33° N, 65 °E to 100 °E during the period 2003–2013. Apart from the above data, mesoscale dynamical parameters such as vertical wind shear of horizontal wind, relative humidity, were also considered to understand their role in invigoration. Case studies have been carried out for the regions having heavy rainfall events & minimal rainfall events during high Aerosol optical depths occasions respectively. Analysis revealed that the heavy rainfall which occurred in this region with higher optical depths might be due to invigoration effect of aerosols wherein the dynamical as well as thermodynamical parameters were also found favourable. Minimal rainfall events were also observed most probably due to the suppression of rain formation/delay in precipitation due to high amount of aerosol concentration in these regions. Prominent 36 such cases were studied all over India during Pre & Post monsoon months.","PeriodicalId":165733,"journal":{"name":"SPIE Asia-Pacific Remote Sensing","volume":"142 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121758489","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
P. G., Rajasekhar M., P. R., Sreeshna T., R. M, S. Ramakrishna
Operational short range prediction of Meso-scale thunderstorms for Sriharikota(13.7°N ,80.18°E) has been performed using two nested domains 27 & 9Km configuration of Weather Research & Forecasting-Advanced Research Weather Model (WRF- ARW V3.4).Thunderstorm is a Mesoscale system with spatial scale of few kilometers to a couple of 100 kilometers and time scale of less than an one hour to several hours, which produces heavy rain, lightning, thunder, surface wind squalls and down-bursts. Numerical study of Thunderstorms at Sriharikota and its neighborhood have been discussed with its antecedent thermodynamic stability indices and Parameters that are usually favorable for the development of convective instability based on WRF ARW model predictions. Instability is a prerequisite for the occurrence of severe weather, the greater the instability, the greater will be the potential of thunderstorm. In the present study, K Index, Total totals Index (TTI), Convective Available Potential Energy (CAPE), Convective Inhibition Energy (CINE), Lifted Index (LI), Precipitable Water (PW), etc. are the instability indices used for the short range prediction of thunderstorms. In this study we have made an attempt to estimate the skill of WRF ARW predictability and diagnosed three thunderstorms that occurred during the late evening to late night of 31st July, 20th September and 2nd October of 2015 over Sriharikota Island which are validated with Local Electric Field Mill (EFM), rainfall observations and Chennai Doppler Weather Radar products. The model predicted thermodynamic indices (CAPE, CINE, K Index, LI, TTI and PW) over Sriharikota which act as good indicators for severe thunderstorm activity.
{"title":"Prediction of severe thunderstorms over Sriharikota Island by using the WRF-ARW operational model","authors":"P. G., Rajasekhar M., P. R., Sreeshna T., R. M, S. Ramakrishna","doi":"10.1117/12.2225068","DOIUrl":"https://doi.org/10.1117/12.2225068","url":null,"abstract":"Operational short range prediction of Meso-scale thunderstorms for Sriharikota(13.7°N ,80.18°E) has been performed using two nested domains 27 & 9Km configuration of Weather Research & Forecasting-Advanced Research Weather Model (WRF- ARW V3.4).Thunderstorm is a Mesoscale system with spatial scale of few kilometers to a couple of 100 kilometers and time scale of less than an one hour to several hours, which produces heavy rain, lightning, thunder, surface wind squalls and down-bursts. Numerical study of Thunderstorms at Sriharikota and its neighborhood have been discussed with its antecedent thermodynamic stability indices and Parameters that are usually favorable for the development of convective instability based on WRF ARW model predictions. Instability is a prerequisite for the occurrence of severe weather, the greater the instability, the greater will be the potential of thunderstorm. In the present study, K Index, Total totals Index (TTI), Convective Available Potential Energy (CAPE), Convective Inhibition Energy (CINE), Lifted Index (LI), Precipitable Water (PW), etc. are the instability indices used for the short range prediction of thunderstorms. In this study we have made an attempt to estimate the skill of WRF ARW predictability and diagnosed three thunderstorms that occurred during the late evening to late night of 31st July, 20th September and 2nd October of 2015 over Sriharikota Island which are validated with Local Electric Field Mill (EFM), rainfall observations and Chennai Doppler Weather Radar products. The model predicted thermodynamic indices (CAPE, CINE, K Index, LI, TTI and PW) over Sriharikota which act as good indicators for severe thunderstorm activity.","PeriodicalId":165733,"journal":{"name":"SPIE Asia-Pacific Remote Sensing","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133015084","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The concentration levels of CO2 in Earth's atmosphere have rapidly increased over the last 250 years. The source of CO2 in the atmosphere is mainly human activity whereas few natural events such as volcanic activity, natural coal fires etc. also contribute to global CO2. The ground-based measurements provide a strong global constraint on both human and natural CO2 fluxes into the atmosphere. However the identification and characterization of strongest natural sources and sinks, and to discriminate the human CO2 emissions from the natural background, more comprehensive measurement network is needed. Such measurements are essential for the formulation of carbon management policies. For both spatial and temporal studies, detailed global measurements can be provided by satellites. The satellite instruments that provide or have provided atmospheric CO2 information include SCIAMACHY, GOSAT and OCO-2. Alongwith comparative study of SCIAMACHY and GOSAT derived CO2, analysis of recently obtained OCO-2 data is also performed. The GOSAT derived concentration values are about 1{2% smaller than those obtained from SCIAMACHY. The spatial and temporal variability of CO2 over the globe as well as over the Indian land boundary is studied. Comparison with the global view NOAA in-situ data and also location specific data is made.
{"title":"Study of CO2 variability over India using data from satellites","authors":"P. Prasad, S. Rastogi, R. Singh","doi":"10.1117/12.2228029","DOIUrl":"https://doi.org/10.1117/12.2228029","url":null,"abstract":"The concentration levels of CO2 in Earth's atmosphere have rapidly increased over the last 250 years. The source of CO2 in the atmosphere is mainly human activity whereas few natural events such as volcanic activity, natural coal fires etc. also contribute to global CO2. The ground-based measurements provide a strong global constraint on both human and natural CO2 fluxes into the atmosphere. However the identification and characterization of strongest natural sources and sinks, and to discriminate the human CO2 emissions from the natural background, more comprehensive measurement network is needed. Such measurements are essential for the formulation of carbon management policies. For both spatial and temporal studies, detailed global measurements can be provided by satellites. The satellite instruments that provide or have provided atmospheric CO2 information include SCIAMACHY, GOSAT and OCO-2. Alongwith comparative study of SCIAMACHY and GOSAT derived CO2, analysis of recently obtained OCO-2 data is also performed. The GOSAT derived concentration values are about 1{2% smaller than those obtained from SCIAMACHY. The spatial and temporal variability of CO2 over the globe as well as over the Indian land boundary is studied. Comparison with the global view NOAA in-situ data and also location specific data is made.","PeriodicalId":165733,"journal":{"name":"SPIE Asia-Pacific Remote Sensing","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134500779","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Current study uses Satellite and Reanalysis data to quantify the effect of aerosol on ET at various space and time scales. All the data are obtained for the period June 2008 to May 2009 over Dibrugarh district, Assam, Indi a where NDVI has limited change of through the year. Monthly Evapo-Transpiration (ET, cumulative), Normalized Difference Vegetation Index (NDVI) and Aerosol Optical Depth (AOD) are retrieved from satellite images of Terra-MODIS. The AOD data are evaluated against in-situ observations. Maximum values of AOD are observed in the pre-monsoon season while minimum AOD values are perceived in October and November. Aerosol Radiative Forcing (ARF) is calculated by using the MERRA data sets of ‘clean-clear radiation’ and ‘clear-radiation’ at surface over the study area. Maximum aerosol radiative forcing is observed during the pre-monsoon season; this is in tune with ground observations. Strong positive correlation (r=0.75) between ET and NDVI is observed and it is found that the dense vegetative surfaces exhibit higher rate of evapo-transpiration. A strong positive correlation (r= -0.85) between ARF at surface and AOD is observed with radiative forcing efficiency of 35 W/m2. A statistical regression equation of ET a s a function of NDVI and AOD i.e. ET = 0.25 + (-84.27) * AOD + (131.51) * NDVI, is obtained that shows a correlation of 0.824.
{"title":"Evapo-transpiration, role of aerosol radiative forcing: a study over a dense canopy","authors":"V. Bhanage, R. Latha, B. Murthy","doi":"10.1117/12.2223643","DOIUrl":"https://doi.org/10.1117/12.2223643","url":null,"abstract":"Current study uses Satellite and Reanalysis data to quantify the effect of aerosol on ET at various space and time scales. All the data are obtained for the period June 2008 to May 2009 over Dibrugarh district, Assam, Indi a where NDVI has limited change of through the year. Monthly Evapo-Transpiration (ET, cumulative), Normalized Difference Vegetation Index (NDVI) and Aerosol Optical Depth (AOD) are retrieved from satellite images of Terra-MODIS. The AOD data are evaluated against in-situ observations. Maximum values of AOD are observed in the pre-monsoon season while minimum AOD values are perceived in October and November. Aerosol Radiative Forcing (ARF) is calculated by using the MERRA data sets of ‘clean-clear radiation’ and ‘clear-radiation’ at surface over the study area. Maximum aerosol radiative forcing is observed during the pre-monsoon season; this is in tune with ground observations. Strong positive correlation (r=0.75) between ET and NDVI is observed and it is found that the dense vegetative surfaces exhibit higher rate of evapo-transpiration. A strong positive correlation (r= -0.85) between ARF at surface and AOD is observed with radiative forcing efficiency of 35 W/m2. A statistical regression equation of ET a s a function of NDVI and AOD i.e. ET = 0.25 + (-84.27) * AOD + (131.51) * NDVI, is obtained that shows a correlation of 0.824.","PeriodicalId":165733,"journal":{"name":"SPIE Asia-Pacific Remote Sensing","volume":"145 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115214894","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
G. S. Jayeshlal, M. Satyanarayana, G. S. Motty, Reji k. Dhaman, V. Krishnakumar, V. P. Mahadevan Pillai
Cirrus clouds are mainly composed of ice crystals and are known to be the major natural contributors to radiative forcing in the Earth’s atmosphere system. Describing the formation and microphysical properties of cirrus clouds and their role in climate models remain a challenging study. Lidar is a unique instrument, which provides the information on the optical and microphysical properties of cirrus clouds with good spatial and temporal resolutions. In this study we present the microphysical properties of cirrus clouds and their temporal variability, obtained using the ground based dual polarisation lidar at the tropical station Gadanki (13.5° N and 79.2° E), India, during the period January2009 to March 2011. Using the method developed in house for deriving range dependent lidar ratio (LR), the lidar measurements are used for deriving the extinction coefficient and to obtain the nature of the scatterers present in the cloud. It is noted that lidar ratio plays an important role and its measurements indicate directly the type of the ice nucleating aerosol particles present in the cloud. The long term data obtained on the structure of the cirrus in this regard are useful in the climate modelling studies.
{"title":"Lidar investigations on the structure and microphysical properties of cirrus at a tropical station Gadanki (13.5° N and 79.2° E), India","authors":"G. S. Jayeshlal, M. Satyanarayana, G. S. Motty, Reji k. Dhaman, V. Krishnakumar, V. P. Mahadevan Pillai","doi":"10.1117/12.2222294","DOIUrl":"https://doi.org/10.1117/12.2222294","url":null,"abstract":"Cirrus clouds are mainly composed of ice crystals and are known to be the major natural contributors to radiative forcing in the Earth’s atmosphere system. Describing the formation and microphysical properties of cirrus clouds and their role in climate models remain a challenging study. Lidar is a unique instrument, which provides the information on the optical and microphysical properties of cirrus clouds with good spatial and temporal resolutions. In this study we present the microphysical properties of cirrus clouds and their temporal variability, obtained using the ground based dual polarisation lidar at the tropical station Gadanki (13.5° N and 79.2° E), India, during the period January2009 to March 2011. Using the method developed in house for deriving range dependent lidar ratio (LR), the lidar measurements are used for deriving the extinction coefficient and to obtain the nature of the scatterers present in the cloud. It is noted that lidar ratio plays an important role and its measurements indicate directly the type of the ice nucleating aerosol particles present in the cloud. The long term data obtained on the structure of the cirrus in this regard are useful in the climate modelling studies.","PeriodicalId":165733,"journal":{"name":"SPIE Asia-Pacific Remote Sensing","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116762421","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Goyal, Ashish Kumar, Ghansham Sangar, M. Mohapatra
Satellite based Nowcasting technique is customized version of Forecast and Tracking the Evolution of Cloud Clusters (ForTraCC), it uses the extrapolation technique that allows for the tracking of Mesoscale convective systems (MCS) radiative and morphological properties and forecasts the evolution of these properties (based on cloud-top brightness temperature and area of the cloud cluster) up to 360 minutes, using infrared satellite imagery. The Thermal Infrared (TIR) channel of the weather satellite has been broadly used to study the behaviour of the cloud systems associated with deep convection. The main advantage of this approach is that for most of the globe the best statistics can only be obtained from satellite observations. Such a satellite survey would provide the statistics of MCSs covering the range of meteorological conditions needed to generalize the result and on the other hand only satellite observations can cover the very large range of space and time scale. The algorithm script is taken from Brazilian Scientist Dr. Danial Vila and implemented it into the Indian environment and made compatible with INSAT-3D hdf5 data format. For Indian region it utilizes the INSAT-3D satellite data of TIR1 (10.8 μm) channel and creates nowcast. The output is made compatible with GUI based software MIAS by generating the output in hdf5 format for better understanding and analysis of forecast. The main features of this algorithm are detection of Cloud Cluster based on Cloud Top Brightness Temperature (CTBT) and area i.e. ≤235 ºK and ≥2400 km2 respectively. The tracking technique based on MCS overlapping areas in successive images. The script has been automized in Auxiliary Data Processing System (ADPS) and generating the forecast file in every half an hour and convert the output file in geotiff format. The geotiff file is easily converted into KMZ file format using ArcGIS software to overlay it on google map and hosted on the web server.
{"title":"Severe thunderstorm activity over Bihar on 21st April, 2015: a simulation study by satellite based Nowcasting technique","authors":"S. Goyal, Ashish Kumar, Ghansham Sangar, M. Mohapatra","doi":"10.1117/12.2222740","DOIUrl":"https://doi.org/10.1117/12.2222740","url":null,"abstract":"Satellite based Nowcasting technique is customized version of Forecast and Tracking the Evolution of Cloud Clusters (ForTraCC), it uses the extrapolation technique that allows for the tracking of Mesoscale convective systems (MCS) radiative and morphological properties and forecasts the evolution of these properties (based on cloud-top brightness temperature and area of the cloud cluster) up to 360 minutes, using infrared satellite imagery. The Thermal Infrared (TIR) channel of the weather satellite has been broadly used to study the behaviour of the cloud systems associated with deep convection. The main advantage of this approach is that for most of the globe the best statistics can only be obtained from satellite observations. Such a satellite survey would provide the statistics of MCSs covering the range of meteorological conditions needed to generalize the result and on the other hand only satellite observations can cover the very large range of space and time scale. The algorithm script is taken from Brazilian Scientist Dr. Danial Vila and implemented it into the Indian environment and made compatible with INSAT-3D hdf5 data format. For Indian region it utilizes the INSAT-3D satellite data of TIR1 (10.8 μm) channel and creates nowcast. The output is made compatible with GUI based software MIAS by generating the output in hdf5 format for better understanding and analysis of forecast. The main features of this algorithm are detection of Cloud Cluster based on Cloud Top Brightness Temperature (CTBT) and area i.e. ≤235 ºK and ≥2400 km2 respectively. The tracking technique based on MCS overlapping areas in successive images. The script has been automized in Auxiliary Data Processing System (ADPS) and generating the forecast file in every half an hour and convert the output file in geotiff format. The geotiff file is easily converted into KMZ file format using ArcGIS software to overlay it on google map and hosted on the web server.","PeriodicalId":165733,"journal":{"name":"SPIE Asia-Pacific Remote Sensing","volume":"105 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123524455","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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