Title : How effective management of green space is beneficial in mitigating the heat stress related risks among the urban residents: a study on the Raiganj urban agglomeration in India
The issue of urban heat islands (UHI) to the sustainability of urban areas has remained a matter of serious concern. A few recent studies revealed that the intensity of UHI is also growing rapidly in medium-class cities due to the rapid degradation of natural vegetation covers. It has caused a significant increase in heat-related illnesses. The study unit selected for this study is Raiganj City in Eastern India. A questionnaire survey with a sample size of 500 households revealed that illnesses such as headaches, dizziness, heat rash, and heat cramp on average increased by more than 10 percent among the residents during the last decade. A few incidents of heatstroke to the family member were also reported by some respondents. Therefore, an assessment concerning a medium-class city is of immense necessity to explore the association between green space and urban heat island (UHI) effect as a means of possible mitigation measure. In this study, the patch level association between green space and land surface temperature (LST) is explored on a spatial-temporal basis to reflect how green space concentration can influence the LST intensity. A total of 12 landscape metrics is incorporated for the evaluation of green space fragmentation and isolation. Further, an additional 6 metrics are included to show the LST patch compactness. The complex relationship between green space patches and LST patches is analyzed by employing multi-scale geographically weighted regression. The output suggests a strong positive relationship between green space fragmentation and isolation to the UHI effect. It showed that a high proportion of green spaces with low fragmentation and isolation particularly in 2000 was the source of sink areas in Raiganj. However, with the rapid removal of green spaces, fragmentation, and isolation in the green spaces increased significantly in the subsequent years. It enhanced the LST intensity and strengthens the UHI effect over the city. This study suggests the requirement of a proper action plan including a future land use land cover planning map for the preservation and enhancement of the compact green spaces. It will help to minimize the effect of heat-related risk among the citizens.