Partha Sarathi Roy

Bio: Partha Sarathi Roy is an academic researcher from International Crops Research Institute for the Semi-Arid Tropics. The author has contributed to research in topics: Land cover & Vegetation. The author has an hindex of 37, co-authored 174 publications receiving 5119 citations. Previous affiliations of Partha Sarathi Roy include World Resources Institute & Department of Space.

Validation of the global land cover 2000 map

Abstract: The Joint Research Centre of the European Commission (JRC), in partnership with 30 institutions, has produced a global land cover map for the year 2000, the GLC 2000 map. The validation of the GLC2000 product has now been completed. The accuracy assessment relied on two methods: a confidence-building method (quality control based on a comparison with ancillary data) and a quantitative accuracy assessment based on a stratified random sampling of reference data. The sample site stratification used an underlying grid of Landsat data and was based on the proportion of priority land cover classes and on the landscape complexity. A total of 1265 sample sites have been interpreted. The first results indicate an overall accuracy of 68.6%. The GLC2000 validation exercise has provided important experiences. The design-based inference conforms to the CEOS Cal-Val recommendations and has proven to be successful. Both the GLC2000 legend development and reference data interpretations used the FAO Land Cover Classification System (LCCS). Problems in the validation process were identified for areas with heterogeneous land cover. This issue appears in both in the GLC2000 (neighborhood pixel variations) and in the reference data (cartographic and thematic mixed units). Another interesting outcome of the GLC2000 validation is the accuracy reporting. Error statistics are provided from both the producer and user perspective and incorporates measures of thematic similarity between land cover classes derived from LCCS

On the use of Standardized Precipitation Index(SPI) for drought intensity assessment

Abstract: Monthly rainfall data from June to October for 39 years were used to compute Standardized Precipitation Index (SPI) values based on two parameter gamma distribution for a low rainfall and a high rainfall districts of Andhra Pradesh state, India. Comparison of SPI with actual rainfall and rainfall deviation from the mean indicated that SPI values under-estimate the intensity of dryness/wetness when the rainfall is very low/very high, respectively. As a result, the SPI in the worst drought years of 2002 and 2006 in the low rainfall district indicated only moderate dryness instead of extreme dryness. SPI values of the high rainfall district showed slightly better stretching in both positive and negative directions, compared to that of the low rainfall district. Further, the SPI values of longer time scales (2, 3 and 4 months) showed an extended range compared to that of 1 month, but the sensitivity in drought years has not improved significantly. Normality tests were conducted based on Shapiro-Wilk statistic, p-values and absolute value of the median to ascertain whether non-normality of SPI is a possible reason. Although the results confirmed normal distribution, the scatter plot indicated deviation of the cumulative probability distribution of SPI from normal probability in the lower and upper ranges. Therefore, it is suggested that SPI as a stand alone indicator needs to be interpreted with caution to assess the intensity of drought. Further investigations should include sensitivity of SPI to the estimated shape and scale at lower and upper bounds of the gamma distribution and use of other distributions, such as Pearson III, to standardize the computational procedures, before using SPI as a substitute to the rainfall deviations from normal, for drought intensity assessment. Copyright © 2009 Royal Meteorological Society

Biomass estimation using satellite remote sensing data—An investigation on possible approaches for natural forest

Abstract: Vegetation type and its biomass are considered important components affecting biosphere-atmosphere interactions. The measurements of biomass per unit area and productivity have been set as one of the goals for International Geosphere-Biosphere Programme (IGBP). Ground assessment of biomass, however, has been found insufficient to present spatial extent of the biomass. The present study suggests approaches for using satellite remote sensing data for regional biomass mapping in Madhav National Park (MP). The stratified random sampling in the homogeneous vegetation strata mapped using satellite remote sensing has been effectively utilized to extrapolate the sample point biomass observations in the first approach.

Tropical forest cover density mapping

Abstract: Forest canopy density is one of the most useful parameters to consider in the planning and implementation of rehabilitation program. This study is development of bio- physical analysis model for obtaining of Forest Canopy Density (FCD) using LANDSAT TM data image analysis. The components of FCD model are four factors; vegetation, bare soil, thermal and shadow. This work is implemented under the research project; PD32/93Rev2(F) of International Tropical Timber Organization (ITTO). Resumen: La densidad de dosel forestal es uno de los parametros cuya inclusion tiene mas utilidad en la planeacion e instrumentacion de programas de rehabilitacion. Este estudio con- siste en el desarrollo de un modelo de analisis biofisico para la obtencion de Densidad de Dosel Forestal (FCD por sus siglas en ingles) por medio del analisis de datos de imagenes LANDSAT TM. Los componentes del modelo FCD son cuatro factores; vegetacion, suelo desnudo, tempera- tura y sombra. Este trabajo forma parte del proyecto de investigacion PD32/93Rev2(F) de la Organizacion Internacional de Maderas Tropicales (ITTO). Resumo: A densidade do copado florestal e um dos parâmetros mais uteis a serem consid- erados no planeamento e implementacao de programas de reabilitacao. Este estudo apresenta o desenvolvimento do modelo de analise biofisica para obtencao da Densidade de Copado Flore- stal (FCD) usando a analise de imagem do LANDSAT TM. As componentes do modelo FCD eram: vegetacao, solo nu, temperatura e sombra. Este trabalho foi implementado pelo projecto de investigacao PD32/93Rev2(F) da Organizacao Internacional para a Madeira Tropical (ITTO).

The Theory of Island Biogeography

Abstract: Preface to the Princeton Landmarks in Biology Edition vii Preface xi Symbols Used xiii 1. The Importance of Islands 3 2. Area and Number of Speicies 8 3. Further Explanations of the Area-Diversity Pattern 19 4. The Strategy of Colonization 68 5. Invasibility and the Variable Niche 94 6. Stepping Stones and Biotic Exchange 123 7. Evolutionary Changes Following Colonization 145 8. Prospect 181 Glossary 185 References 193 Index 201

Mitigation and Adaptation Strategies for Global Change

Abstract: ▶ Addresses a wide range of timely environment, economic and energy topics ▶ A forum to review, analyze and stimulate the development, testing and implementation of mitigation and adaptation strategies at regional, national and global scales ▶ Contributes to real-time policy analysis and development as national and international policies and agreements are discussed and promulgated ▶ 94% of authors who answered a survey reported that they would definitely publish or probably publish in the journal again

Remote Sensing And Image Interpretation

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