ANNOUNCEMENTS
Urban climate is a regional trend that is globally characterised by the phenomenon of Urban Heat Island (UHI) in which the centre of urban areas having air and land surface temperatures (LST) higher as compared to its surrounding areas. It is not a static phenomenon and exhibits temporal (diurnal and seasonal) dynamics and spatial variations. Therefore, mapping and monitoring variations in land use/land cover (LULC) and surface temperature becomes extremely crucial.
This thesis assesses the spatial and temporal profiles of thermal environment and links them to LULC patterns in Delhi. The first objective of the research aims at performing UHI analysis for Delhi using LULC information and LST retrieved from the satellite imageries over the years. Results were validated using ground observations of LST. The urbanized area and urban footprint map statistics show an increase in urban-suburban built-up area with a decrease in rural open lands over the last decade.
The second objective focuses on temporal analysis of UHI in seasonal and diurnal domains using UHI Intensity (UHI-I). Three different approaches were used to map UHI-I; Anomaly based, Standard Deviation (σ) based, and Normalization based approaches. Maximum UHI-I varies in order of summer > monsoon > spring > post-monsoon > winter. UHI is dominant in city centre during spring and monsoon, and shifts to south-west in summers and post-monsoon seasons. Typical UHI profile is visible at night with high LST in city centres in contrast to low rural surface temperatures owing to variable thermal properties.
The third objective explores potential of urban material and colours for mitigating UHI. Building material such as plastic, porcelain tile and sandstone exhibit high temperature in night throughout the year. Metal, solar panels and glass show relatively high day surface temperatures. Grass lawns have low temperatures throughout the year (both day and night) and therefore, can be good for mitigating measures. White paint exhibits minimum temperature throughout the year, while Red colour is better than blue, green and black for mitigating surface heat. Using concrete without any paint colours is however a much better choice.
In conclusion the thesis provides recommendations based on the research work conducted. The thesis suggests ways in which this kind of research can be most profitably developed.
Shodhganga Link
