Impact Analysis of the Environmental Changes Index of Urban Sprawl on the Severe Weather Storm;Case Studies of Tehran, Mashhad, Ankara, and Istanbul

Understanding the effect of urban physical development on urban air instability is a challenging issue. The aim of the present study was to analyze the environmental change index of urban sprawls and its relationship with the severe weather threat index (SWEAT) within four major cities of Iran and Turkey in the current situation (2018) and future probabilities (2030).

In this study, severe weather storm index data were extracted from upper-air level data in the radiosonde stations of Tehran, Mashhad, Ankara, and Istanbul. Also, urban sprawl data were obtained from the global data of the extent of human settlements.

Analyzing the urban sprawl data revealed that the cities of Ankara and Istanbul have the highest physical development, respectively. According to the findings of the urban sprawl development model, the most severe rate of urban sprawl development is predicted for the city of Tehran. Based on the calculation of the environmental change index (ΔY) caused by sprawl dispersion, it was determined that the values ​​of this index will be estimated between 0.61 to 1.98 for the four urban case studies in the future, where the most severe index (1.98) can be calculated for Tehran.

Calculation of SWEAT in 2018 shows that the urban sprawl development and its resulting environmental changes had a significant effect on increasing occurrences of severe weather storms in the all urban areas with a correlation rate of 0.913. The forecast of this index also shows that the average severe weather storm index will increase between %19 to %118 by 2030 in the all urban areas, in which the most value is predictable for the city of Tehran.