samarendra Karmakar - Academia.edu (original) (raw)
Chairman of National Oceanographic and Maritime Institute (NOAMI), Former Director of Bangladesh Meteorological Department and SAARC Meteorological Research Centre, Former Permanent Representative of Bangladesh with WMO, Former Vulnerability Assessment and Capacity Development Expert of Bangladesh Centre for Advanced Studies (BCAS)
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Papers by samarendra Karmakar
Journal of Bangladesh Academy of Sciences, 2012
The forecasting techniques for the prediction of nor’westers and associated winds and rainfall ha... more The forecasting techniques for the prediction of nor’westers and associated winds and rainfall have been developed. Four linear multiple regression equations for computation of maximum gusty wind speed associated with nor’westers have been developed. The computed values of maximum gusty wind speed have statistically significant correlation with the actual maximum gusty wind speed. The regression equations have been verified with data of year (2005) and will be useful for the operational meteorologists for the computations of maximum gusty wind speed associated with nor’westers. Simple linear regression equations and linear multiple regression equations have also been developed for the statistical prediction of 24 hrs rainfall over Dhaka, country-averaged 24 hrs rainfall over Bangladesh and 24 hrs maximum rainfall over Bangladesh due to nor’westers. The correlation co-efficient corresponding to these regression equations are statistically significant. These equations have also been v...
Journal of Geographic Information System, 2010
An exhaustive knowledge of flood risk in different spatial locations is essential for developing ... more An exhaustive knowledge of flood risk in different spatial locations is essential for developing an effective flood mitigation strategy for a watershed. In the present study, a risk-vulnerability analysis to flood is performed. Four components of vulnerability to flood: 1) physical, 2) economic, 3) infrastructure and 4) social; are evaluated individually using a Geographic Information System (GIS) environment. The proposed methodology estimates the impact on infrastructure vulnerability due to inundation of critical facilities, emergency service stations and bridges. The components of vulnerability are combined to determine an overall vulnerability to flood. The exposures of land use/land cover and soil type (permeability) to flood are also considered to include their effects on severity of flood. The values of probability of occurrence of flood, vulnerability to flood, and exposures of land use and soil type to flood are used to finally compute flood risk at different locations in a watershed. The proposed methodology is implemented for six major damage centers in the Upper Thames River watershed, located in the SouthWestern Ontario, Canada to assess the flood risk. An information system is developed for systematic presentation of the flood risk, probability of occurrence of flood, vulnerability to flood, and exposures of land use and soil type to flood by postal code regions or Forward Sortation Areas (FSAs). The flood information system is designed to provide support for different users, i.e., general public, decision-makers and water management professionals. An interactive analysis tool is developed within the information system to assist in evaluation of the flood risk in response to a change in land use pattern.
MAUSAM, 2021
The present study is an attempt to study different Modified Stability Indices in relation to the ... more The present study is an attempt to study different Modified Stability Indices in relation to the occurrence of severe thunderstorms/nor’westers in order to find out the critical values of different modified indices favorable for the formation of thunderstorms in Bangladesh. Computations have also been made for the stations in and around Bangladesh for studying the spatial distribution of the modified stability indices. The Modified Instability Indices such as Modified Cross Total Index (MCT), Modified Vertical Total Index (MVT), Modified Total Totals Index (MTT), Modified SWEAT Index (MSWI), Modified K-Index (MKI) and Modified Energy Index (MEI) show greater instability of the troposphere in the morning as compared to CT, VT, TT, SWI, KI and EI. The critical values of different modified instability indices at 0000 UTC over Dhaka are: MCT >= 20° C, MVT >= 26° C, MTT >= 46° C, MSWI > 300, MKI >= 40° C and MEI < -6 joules/gm respectively for the nor’westers to occur i...
MAUSAM, 2021
Attempts have been made to compute the precipitable water content of the troposphere, weighted av... more Attempts have been made to compute the precipitable water content of the troposphere, weighted average water vapour and to correlate these parameters with different instability indices and also with the next 24-hr rainfall, next 24-hr maximum rainfall and next 24-hr country averaged rainfall in order to predicting rainfall due to nor’westers in Bangladesh. It has been found that the maximum number of nor’westers occur when the precipitable water is 25-45 mm hr-1 between 1000 and 500 hPa, the maximum frequency being 48 in the range of 35-45 mm hr-1. The spatial distribution of precipitable water indicates that the maximum precipitable water is concentrated over the area near the places of nor’westers. The specific humidity has been found to increase on the dates of occurrence of nor’westers in Bangladesh on most occasions. Maximum number of nor’westers occurs when the weighted average specific humidity between the surface (1000 hPa) and 500 hPa is 8-12 g kg-1, the maximum frequency b...
MAUSAM
The changes in the vertically-integrated tropospheric moisture. energy and their fluxes over Bang... more The changes in the vertically-integrated tropospheric moisture. energy and their fluxes over Bangladesh have been studied during the landfall of three major cyclones at Bangladesh coast in the recent past. It has been found that the vertically- integrated tropospheric moisture, dry static energy, latent energy and total energy over the country have a tendency to decrease at the formation stages of the cyclones in the Bay of Bengal and then the same shows significant increase as the cyclones move northwards for ultimate landfall. The integrated zonal and meridional fluxes of moisture, dry static energy, latent energy and total energy exhibit significant changes both in magnitudes and signs during the northward movement of the cyclones.
Journal of Bangladesh Academy of Sciences, 2012
The forecasting techniques for the prediction of nor’westers and associated winds and rainfall ha... more The forecasting techniques for the prediction of nor’westers and associated winds and rainfall have been developed. Four linear multiple regression equations for computation of maximum gusty wind speed associated with nor’westers have been developed. The computed values of maximum gusty wind speed have statistically significant correlation with the actual maximum gusty wind speed. The regression equations have been verified with data of year (2005) and will be useful for the operational meteorologists for the computations of maximum gusty wind speed associated with nor’westers. Simple linear regression equations and linear multiple regression equations have also been developed for the statistical prediction of 24 hrs rainfall over Dhaka, country-averaged 24 hrs rainfall over Bangladesh and 24 hrs maximum rainfall over Bangladesh due to nor’westers. The correlation co-efficient corresponding to these regression equations are statistically significant. These equations have also been v...
Journal of Geographic Information System, 2010
An exhaustive knowledge of flood risk in different spatial locations is essential for developing ... more An exhaustive knowledge of flood risk in different spatial locations is essential for developing an effective flood mitigation strategy for a watershed. In the present study, a risk-vulnerability analysis to flood is performed. Four components of vulnerability to flood: 1) physical, 2) economic, 3) infrastructure and 4) social; are evaluated individually using a Geographic Information System (GIS) environment. The proposed methodology estimates the impact on infrastructure vulnerability due to inundation of critical facilities, emergency service stations and bridges. The components of vulnerability are combined to determine an overall vulnerability to flood. The exposures of land use/land cover and soil type (permeability) to flood are also considered to include their effects on severity of flood. The values of probability of occurrence of flood, vulnerability to flood, and exposures of land use and soil type to flood are used to finally compute flood risk at different locations in a watershed. The proposed methodology is implemented for six major damage centers in the Upper Thames River watershed, located in the SouthWestern Ontario, Canada to assess the flood risk. An information system is developed for systematic presentation of the flood risk, probability of occurrence of flood, vulnerability to flood, and exposures of land use and soil type to flood by postal code regions or Forward Sortation Areas (FSAs). The flood information system is designed to provide support for different users, i.e., general public, decision-makers and water management professionals. An interactive analysis tool is developed within the information system to assist in evaluation of the flood risk in response to a change in land use pattern.
MAUSAM, 2021
The present study is an attempt to study different Modified Stability Indices in relation to the ... more The present study is an attempt to study different Modified Stability Indices in relation to the occurrence of severe thunderstorms/nor’westers in order to find out the critical values of different modified indices favorable for the formation of thunderstorms in Bangladesh. Computations have also been made for the stations in and around Bangladesh for studying the spatial distribution of the modified stability indices. The Modified Instability Indices such as Modified Cross Total Index (MCT), Modified Vertical Total Index (MVT), Modified Total Totals Index (MTT), Modified SWEAT Index (MSWI), Modified K-Index (MKI) and Modified Energy Index (MEI) show greater instability of the troposphere in the morning as compared to CT, VT, TT, SWI, KI and EI. The critical values of different modified instability indices at 0000 UTC over Dhaka are: MCT >= 20° C, MVT >= 26° C, MTT >= 46° C, MSWI > 300, MKI >= 40° C and MEI < -6 joules/gm respectively for the nor’westers to occur i...
MAUSAM, 2021
Attempts have been made to compute the precipitable water content of the troposphere, weighted av... more Attempts have been made to compute the precipitable water content of the troposphere, weighted average water vapour and to correlate these parameters with different instability indices and also with the next 24-hr rainfall, next 24-hr maximum rainfall and next 24-hr country averaged rainfall in order to predicting rainfall due to nor’westers in Bangladesh. It has been found that the maximum number of nor’westers occur when the precipitable water is 25-45 mm hr-1 between 1000 and 500 hPa, the maximum frequency being 48 in the range of 35-45 mm hr-1. The spatial distribution of precipitable water indicates that the maximum precipitable water is concentrated over the area near the places of nor’westers. The specific humidity has been found to increase on the dates of occurrence of nor’westers in Bangladesh on most occasions. Maximum number of nor’westers occurs when the weighted average specific humidity between the surface (1000 hPa) and 500 hPa is 8-12 g kg-1, the maximum frequency b...
MAUSAM
The changes in the vertically-integrated tropospheric moisture. energy and their fluxes over Bang... more The changes in the vertically-integrated tropospheric moisture. energy and their fluxes over Bangladesh have been studied during the landfall of three major cyclones at Bangladesh coast in the recent past. It has been found that the vertically- integrated tropospheric moisture, dry static energy, latent energy and total energy over the country have a tendency to decrease at the formation stages of the cyclones in the Bay of Bengal and then the same shows significant increase as the cyclones move northwards for ultimate landfall. The integrated zonal and meridional fluxes of moisture, dry static energy, latent energy and total energy exhibit significant changes both in magnitudes and signs during the northward movement of the cyclones.
Proceedings of the 18th Annual Meeting of the Asia Oceania Geosciences Society (AOGS 2021), Apr 2022
The 18th Annual Meeting of the Asia Oceania Geosciences Society (AOGS 2021) was held from 1st to ... more The 18th Annual Meeting of the Asia Oceania Geosciences Society (AOGS 2021) was held from 1st to 6th August 2021. This proceedings volume includes selected extended abstracts from a challenging array of presentations at this conference. The AOGS Annual Meeting is a leading venue for professional interaction among researchers and practitioners, covering diverse disciplines of geosciences.
USAID supported CREL project conducted Participatory Climate Vulnerability Assessment (PCVA) at a... more USAID supported CREL project conducted Participatory Climate Vulnerability Assessment (PCVA) at around 700 villages in around 21 forest PAs by engaging around 11,000 local people and key stakeholders. They have identified climate trends, vulnerabilities and adaptation measures in selected sectors (like, agriculture, water).The local communities are now empowered with the new knowledges that they have been generated through PCVA and more importantly they are making negotiations with the relevant institutions for implementing their adaptation plans. PCVA findings have been included in Annual Development Plans (ADP) of 30 Union Parishads (UP).