応用水文 = Applied hydrology

Challenges and strategies for urban green-space planning in cities undergoing densification: A review

Assessing street-level urban greenery using Google Street View and a modified green view index

Urban Neighborhood Green Index – A measure of green spaces in urban areas

We are all familiar with the fact that cities are generally warmer than the surrounding, more rural areas. We see it referenced most nights in our television weather reports. It is especially significant on nights with clear skies and light winds which favor radiational cooling. This is most significant in the rural areas but in the city, the excess heat absorbed during the day and the local heat sources maintain higher nighttime readings. During the days or nights with strong winds and clouds the differences are minimzed due to mixing and the advective cooling of the city by the winds.

The urban heat island

GIS based analysis for assessing the accessibility at hierarchical levels of urban green spaces

Urban climate studies crucially depend on various urban morphological parameters. The availability of these parameters assists in understanding wind flow inside urban areas, Urban Heat Island (UHI) phenomenon and also aids in estimation of anthropogenic heat in Numerical Weather Prediction models for improved forecast. Of the two approaches used, micrometeorological approach is un-suitable for urban applications due to various operational complexities. Morphometric approaches are more feasible to use in urban areas but their estimation requires automation. The paper presents a software suite which uses novel and existing algorithms to compute variety of urban morphometric parameters including frontal area, height-to-width ratio and sky view factor, which further can be used for the computation of aerodynamic parameters. The application is developed using open source technologies and each component is tested over a sample dataset. The estimated values were validated against manually calculated values and error percentage was found to be within 3% and then demonstrated on a real city database. The developed application can be effectively utilized for urban climate modeling studies, as it enables users to compute urban morphology parameters.

Urban Morphology Extractor: A spatial tool for characterizing urban morphology

In this study, an attempt has been made to evaluate the information content available in IRS P6 LISS IV data for the identification of urban features and u rban mapping. Level-III of the urban land use classification at the scale of 1 : 10,000 was successfully attempted for Dehradun city and its environs. A qual itative and quantitative evaluation of IRS P6 LISS IV data has also been done with PAN-sharpened LISS III data. The boundaries of polygon features, road intersections, contrast with the surroundings are more precise on LISS IV data in comparison to merged data. It is also found that 100% more linear features can be e xtracted with IRS P6 LISS IV data compared to PAN-sharpened LISS III product.

Enhanced capabilities of IRS P6 LISS IV sensor for urban mapping

The present era can be better known as era of urbanization as day by day more population is concentrating in urban areas. Dehradun urban area has become a regional service centre for entire region after becoming the capital of Uttarakhand state in 1999, contributing very high rate of urban growth. For a resource and urban planner, it is important to monitor and understand the dynamics of urban growth continuously. In this study, the Dehradun urban area has been analyzed based on 8-directional wind rose scheme using remote sensing satellite data. The analysis shows that Dehradun urban area has grown 160% in size from1987 to 2008 and almost doubled during 1998-2008. More urban growth is seen in south, south east and south west direction. The growth radius has increased to 15 kms from the heart of the city, whereas it was mere 8 kms till 1987. The method is easy to understand even for a person not a specialist in remote sensing and GIS technology and gives a clear insight of urban growth in different directions and distances from city centre.

Kshama Gupta

Papers

Urban Neighborhood Green Index – A measure of green spaces in urban areas

GIS based analysis for assessing the accessibility at hierarchical levels of urban green spaces

Urban Morphology Extractor: A spatial tool for characterizing urban morphology

Enhanced capabilities of IRS P6 LISS IV sensor for urban mapping

Unprecedented growth of dehradun urban area: a spatio-temporal analysis