Local Threshold as an effective heat index for building heat resilient cities.

Historically, urban heat island intensity has been a measure of urban heating and multiple researchers across the world have mapped the UHII for various cities. The limited signature of the urban heat island intensity is unable to explain and assess varied impacts of extreme heat on human settlements. The urban heat island intensity as a concept is limited to temperature variations and intensities whereas the challenge of extreme heat in cities goes beyond “hot-spot” identification, it is more about the impact of heat on various factors like human health, infrastructure, energy consumption, etc. The impact of extreme heat is more than just heating, it revolves around other heat indices which are governed by “Local Threshold”. The subject of local threshold remains underdeveloped and unexplored. Since the climate varies from location to location, the concept of a EHEs and its threshold often depends upon location, geographical conditions, degree of adaptation of the population and many other factors. This makes it necessary to have regionally specific warning regimes. Hence, it is important to address differential heat risks through the development of local thresholds at city level or even for a particular climatic region. The threshold values are set at a level associated with a negative human response as indicated by the long-term relationship between some measures of heat indices. There is a need to design the guidelines of heat resilience around “local threshold”. The study tries to propose the idea of hyperlocal local threshold centric approach for planning of heat resilience in a city. The study has 4 parts – determining mortality based local threshold, conducting LCZ based heat exposure study considering the local threshold and lastly, highlighting the importance of local threshold.