Raihan Ahmed

Bio: Raihan Ahmed is an academic researcher from Jamia Millia Islamia. The author has contributed to research in topics: Climate change & Vegetation. The author has an hindex of 11, co-authored 28 publications receiving 347 citations.

Analyzing land surface temperature distribution in response to land use/land cover change using split window algorithm and spectral radiance model in Sundarban Biosphere Reserve, India

Abstract: The paper utilized Landsat 5 TM and Landsat 8 OLI for analyzing land use/land cover change and its impact on land surface temperature in Sundarban Biosphere Reserve, India. Split window algorithm and spectral radiance model were used for determining land surface temperature from Landsat 8 OLI and Landsat 5 TM, respectively. The land use land cover change analysis revealed phenomenal increase in the waterlogged areas followed by settlement and paddy and a decrease in open forest followed by deposition and water body. The distribution of average change in land surface temperature shows that water recorded highest increase in temperature followed by deposition, open forest and settlement. Overlay of the transect profiles drawn on land use/land cover change map over land surface temperature map revealed that the land surface temperature has increased in those areas which were transformed from open forest to paddy, open forest to settlement, paddy to settlement and deposition to settlement. The study demonstrated that increase in non-evaporating surfaces and decrease in vegetation have increased the surface temperature and modified the temperature of the study area.

Assessing spatio-temporal health of forest cover using forest canopy density model and forest fragmentation approach in Sundarban reserve forest, India

Abstract: We used forest canopy density model for examining spatial–temporal variation in canopy closure in Sundarban Forest in India and validated the health with fragmentation model. Statistics derived through forest canopy model revealed that most of the changes in forest canopy density occurred in 60–80 % class during 1990–2011. Areas having >80 % and 40–60 % canopy density registered decrease in density while the remained classes 20–40 % and <20 % gained the proportion of decreased density from upper density classes. Forest fragmentation model classified the forested areas into four categories of disturbance-core, perforated, edge and patch based on 200 m edge width. Fragmentation model revealed that the perforated and edge areas have decreased while patch area has increased. Overall core area has increased due to decline in perforated area and consequently experienced decrease in canopy closure. The study demonstrated usefulness of forest canopy density and fragmentation models for assessing the health of the forests.

Assessing coastal island vulnerability in the Sundarban Biosphere Reserve, India, using geospatial technology

Abstract: Rising sea levels and the increasing intensity of storm surges and tropical cyclones due to climate change and the resulting dynamic shifts in shoreline positions have dramatically increased the exposure risk and vulnerability of local communities inhabiting the ecologically sensitive deltaic tracts of the Sunderbans in India. The impacts arising from such hazard events on this fragile ecosystem need to be gauged to ameliorate the lives and livelihoods of these residents. This article examines the spatial distribution of vulnerability to coastal hazards within the Sundarban Biosphere Reserve (SBR) in India. For this, we have utilized several structural and process variables, which were integrated to construct a coastal vulnerability index (CVI), using the square root equation. The coastlines of the islands located within the SBR were overlain by 543 grids, each of 2 × 2 km dimension, to assign the risk rank for each considered variable. This revealed that of the total shoreline length (754 km), nearly one-fourth was very highly vulnerable, followed by highly vulnerable (27.8%), moderately vulnerable (27.9%) and low vulnerability (18.8%). Of the total islands located in these grids (27), the coastline of eleven islands was found to have very high vulnerability, five experienced high vulnerability, eight recorded moderate vulnerability while only three had low vulnerability status. The ambient geomorphological characteristics, coastal area slope, the rate of shoreline change and sea level rise were significant variables that accorded high and very high vulnerability to the islands. The CVI helped in identifying islands that require immediate attention for lessening the impact of climate change induced hazards in the SBR and also aided the assessment of the physical and coastal vulnerability conditions of these islands. This approach can be effectively utilized for assessing coastal vulnerability and for creating a holistic approach towards coastal conservation and management.

Exploring climate variability and its impact on drought occurrence: Evidence from Godavari Middle sub-basin, India

Abstract: Godavari middle sub-basin covering one district of Telangana state and eleven districts of Maharashtra state in India has been experiencing severe drought due to climate variability over the past several decades. Lying in the rain shadow zone of Western Ghats (mountain pass), it receives scant rainfall. Therefore, monitoring and assessing of drought is essential for lessening the impact on communities' livelihood and environment. We utilized forty grid points data from global weather data for SWAT portal during 1979–2013 for assessing drought conditions. Trends in important meteorological variables namely precipitation, temperature, wind speed, solar radiation and relative humidity were analyzed to examine the climate variability in the study area. Standardized precipitation index (SPI) was determined for one, three, six and twelve month drought. Mann Kendall test and Sen's slope were used to analyze trend in precipitation.Multiple linear regression was performed to establish relationship between meteorological variables and drought. Interpolation method of geographical information system (GIS) was utilized for spatial analyses of climate variability, drought and trend in precipitation in the study area. Findings revealed that watersheds located in south-western part of the sub-basin experienced decreasing trend in precipitation and consequent frequent droughts. The study further reveals that the meteorological variables have more impact on short-term drought.

Land suitability assessment for sugarcane cultivation in Bijnor district, India using geographic information system and fuzzy analytical hierarchy process

Abstract: Land suitability evaluation is prerequisite for assessing the limitations for sustainable land use planning. We used ten site specific criteria (rainfall, texture, drainage, soil depth, slope, distance to major road, distance to nearest sugar mill, erosion hazard, risk of flooding and pH) and applied weighted multi-criteria evaluation (MCE) technique in a geographic information system (GIS) environment to evaluate land suitability for sugarcane cultivation in Bijnor district, India. The weightage of all the parameters was calculated through fuzzy analytical hierarchy process. Sugarcane suitability map was prepared integrating various parameters through weighted overlay analysis. The map was categorized as highly suitable (S1), moderately suitable (S2), marginally suitable (S3) and unsuitable (N). The analysis revealed that of the total cultivable land of the district, largest area (61%) was highly suitable followed by moderately suitable (24%), marginally suitable (7%) and unsuitable (8%) for sugarcane cultivation. Nagina, Najibabad and Bijnor sub-districts need attention of land managers and policy makers to remove the limitations and increase the suitability of sugarcane in such areas. Only 7% area was unsuitable for sugarcane cultivation. Slope, soil depth and erosion hazard were the major limiting factors making the land unsuitable for sugarcane cultivation. Therefore, these areas should be given priority for land and soil restoration efforts. The study showed effectiveness of integrated GIS and MCE approach for land suitability analysis of sugarcane.

Climate Change 2007: Impacts, Adaptation and Vulnerability.

Abstract: Impatti, adattamento e vulnerabilita Le cause e le responsabilita dei cambiamenti climatici sono state trattate sul numero di ottobre della rivista Cda. Approfondiamo l’argomento presentando il documento: “Cambiamenti climatici 2007: impatti, adattamento e vulnerabilita” votato ad aprile 2007 dal secondo gruppo di lavoro del Comitato Intergovernativo sui Cambiamenti Climatici (Intergovernmental Panel on Climate Change). Si tratta del secondo di tre documenti che compongono il quarto rapporto sui cambiamenti climatici.

Climate change 2014 - Mitigation of climate change

Abstract: The talk with present the key results of the IPCC Working Group III 5th assessment report. Concluding four years of intense scientific collaboration by hundreds of authors from around the world, the report responds to the request of the world's governments for a comprehensive, objective and policy neutral assessment of the current scientific knowledge on mitigating climate change. The report has been extensively reviewed by experts and governments to ensure quality and comprehensiveness.

Physically-based Assessment of Hurricane Surge Threat under Climate Change

Abstract: United States. National Oceanic and Atmospheric Administration (Postdoctoral Fellowship Program)