نقش تغييرات كاربري اراضي بر فرم فضايي جزاير حرارتي در شهر مشهد

The Role of Land Use Changes in Spatial form of Heat Islands in Mashhad City

ﻃﯽ ﭼﻬﺎر دﻫﻪ اﺧﯿﺮ رﺷﺪ ﺷﺘﺎﺑﺎن ﺷﻬﺮﻧﺸﯿﻨﯽ ﺳﺒﺐ ﺗﻐﯿﯿﺮ و ﺗﺤﻮل ﭘﺪﯾﺪهﻫﺎي ﻃﺒﯿﻌﯽ ﺗﻐﯿﯿﺮ و ﺗﺤﻮل ﺷﺪهاﻧﺪ. اﯾﻦ ﺗﻐﯿﯿﺮات در ﻧﻬﺎﯾﺖ ﻣﻮﺟﺐ ﺗﻐﯿﯿﺮات دﻣﺎي ﺳﻄﺢ زﻣﯿﻦ ﺷﺪه اﺳﺖ. ﻫﺪف از اﯾﻦ ﻣﻄﺎﻟﻌﻪ ﺑﺮرﺳﯽ راﺑﻄﻪ ﺗﻐﯿﯿﺮات ﮐﺎرﺑﺮي اراﺿﯽ و ﺗﻐﯿﯿﺮات ﻣﮑﺎﻧﯽ ﺟﺰاﯾﺮ ﺣﺮارﺗﯽ ﺷﻬﺮ ﻣﺸﻬﺪ در ﺑﺎزه زﻣﺎﻧﯽ 1998 ﺗﺎ 2016 اﺳﺖ. ﺑﺪﯾﻦ ﺗﺮﺗﯿﺐ ﺑﺎ اﺳﺘﻔﺎده از ﺗﺼﺎوﯾﺮ ﻣﺎﻫﻮاره ﻟﻨﺪﺳﺖ، ﺳﻨﺠﻨﺪه اﺳﺖ. ﺑﺎ ﺗﻮﺟﻪ ﺑﻪ اﻓﺰاﯾﺶ ﻣﺤﺪوده ﺳﺎﺧﺘﻪ ﺷﺪه از ﺳﺎل 1998 ﺗﺎ 2016 ﺟﺰاﯾﺮ ﺣﺮارﺗﯽ از ﺧﺎرج از ﺷﻬﺮ ﺑﻪ داﺧﻞ ﺷﻬﺮ اﻧﺘﻘﺎل ﭘﯿﺪا ﮐﺮده اﺳﺖ و ﺑﺎ ﺳﻄﻮح ﺳﺨﺖ و ﻏﯿﺮﻗﺎﺑﻞ ﻧﻔﻮذ ﻣﻨﻄﺒﻖ ﺷﺪه اﻧﺪ. ﭘﯿﺶ ﺑﯿﻨﯽ ﺻﻮرت ﮔﺮﻓﺘﻪ ﺗﺎ ﺳﺎل 2030 ﻧﺸﺎن ﻣﯽدﻫﺪ ﮐﻪ رﺷﺪ ﺷﻬﺮ ﺑﯿﺸﺘﺮ در ﻧﻮاﺣﯽ ﺷﻤﺎﻟﯽ ﻏﺮﺑﯽ ﺧﻮاﻫﺪ ﺑﻮد و در ﻧﻮاﺣﯽ ﺟﻨﻮﺑﯽ ﺑﺎ ﺗﻮﺟﻪ ﺑﻪ اﯾﻨﮑﻪ ارﺗﻔﺎﻋﺎت ﻗﺮار دارد ﺷﻬﺮ رﺷﺪ ﮐﻤﺘﺮي ﺧﻮاﻫﺪ داﺷﺖ.

During the last four decades, the rapid growth of urbanization has dramatically transformed many natural phenomena. Such changes led eventually to changes in the Earth's surface temperature. The purpose of this study was to investigate the relationship between land use changes and spatial variations of thermal islands in Mashhad from 1998 to 2016. Thus, land surface temperature and land use changes of Mashhad were extracted using Landsat satellite imagery (1998- 2016). The CA Markov model has also been used to simulate and predict the expansion of Mashhad. From 1998 to 2016, the constructed area, green space, rangeland and barren lands are changed from 138.52, 46.49, 35.85 and 100.71 square kilometers to 198.87, 29.98, 31.29 and 64.62 square kilometers, respectively. Thermal islands in terms of number and extent in 1998 were less extensive and less synchronous than in 2016. In 1998 the maximum level of temperature was between 42 to 48 degrees Celsius but it reached 46 to 52 in 2016. With respect to the expansion of constructed area in the mentioned time period, the thermal islands are moved from outside of the city to the inside and have been overlapped with hard and impenetrable planes. The obtained results from the prediction illustrate that the expansion of city will occur in northwestern sides more than the others and it will be less in southern sides due to the existence of altitudes.