نوع مقاله : مقاله پژوهشی
نویسنده
دانشیار گروه مهندسی آب دانشگاه شهرکرد
چکیده
این پژوهش با هدف بررسی تغییرات پوشش برف شمال غرب استان چهارمحال و بختیاری (منطقه کوهرنگ) در دهه دوم قرن 21 (سال های 2014 تا 2020) و مقایسه آن با متوسط پوشش برف در دهه پایانی قرن بیستم انجام گرفت. برای این منظور تصاویر ماهواره لندست 5 و 8 در گذر ماه فوریه سال های 2014 تا 2020 و چهار گذر در سال های 1991، 1995، 1997 و 2000 (جهت محاسبه میانگین پوشش برف دهه پایانی قرن 20)، مورد بررسی قرار گرفتند. در این راستا میزان پوشش برف منطقه در سال های مورد بررسی با استفاده از شاخص اصلاح شده تفاضلی نرمال شده پوشش برف (NDSI) محاسبه و مورد مقایسه قرار گرفت. نتایج حاصل از این شاخص نشان داد که کمترین میزان سطح پوشش برفی مربوط به سال 2018 و به میزان 8/1363 کیلومترمربع و بیشترین میزان معادل 7/4263 کیلومترمربع و مربوط سال 2014 میباشد. همچنین نتایج نشان داد که میزان پوشش برف در سال های مورد بررسی در دهه دوم قرن 21 به میزان 14 درصد (در سال 2014) تا 5/72 درصد (در سال 2018) نسبت به میانگین پوشش برف دهه پایانی قرن بیستم کاهش یافته است. نتایج بررسی روند تغییرات ارتفاع برف بوسیله روش من کندال در ایستگاه همدیدی کوهرنگ نیز نشاندهنده کاهش چشمگیر و معنی دار ارتفاع برف به میزان 78 میلیمتر در سال در ماه ژانویه و 151 میلیمتر در سال در ماه فوریه است.
کلیدواژه‌ها
عنوان مقاله [English]
Investigation of Snow Cover Changes in Kohrang Area of Chaharmahal and Bakhtiari Province Using Landsat Satellite Image Processing
نویسنده [English]
- Ahmad reza Ghasemi
Associate Professor, Department of Water Engineering, Shahrekord University
چکیده [English]
This research was conducted with the aim of investigating the snow cover changes in the northwest of Chaharmahal and Bakhtiari province (Kohrang region) in the second decade of the 21st century (2014 to 2020) and comparing it with the average snow cover in the last decade of the 20th century. For this purpose, the images of Landsat 5 and 8 satellites for February from 2014 to 2020 and also four passes in the years 1991, 1995, 1997 and 2000 (to calculate the average snow cover of the last decade of the 20th century) were analyzed. The amount of snow cover was calculated using the normalized differential modified index of snow cover (NDSI) index. The results of the NDSI showed that the lowest amount of snow cover is 1363.8 square kilometers in 2018 and the highest is 4263.7 square kilometers in 2014., The results also showed that the amount of snow cover in the investigated years in the second decade of the 21st century decreased by 14% (in 2014) to 72.5% (in 2018) compared to the average snow cover in the last decade of the 20th century. The results of Mann-Kendal analysis of trend in snow height at the Kohrang station also indicate a significant decrease in snow height by 78 mm per year in January and 151 mm per year in February
کلیدواژه‌ها [English]
- Snow cover
- Chaharmahal and Bakhtiari
- Modified NDSI
- Landsat
- AlemuZ., andDioha M. 2020. Climate change and trend analysis of temperature: the case of Addis Ababa, Ethiopia. Environmental Systems Research. 27: https://doi.org/10.1186/s40068-020-00190-5.
- Asghari S., and Modirzade R. 2020. Estimation of changes in snow depth in Ardabil and Sarein city using sentinel1 satellite data with radar interferometry method. Iran-Water Resources Research. 16: 249-917 (In Persian).
- Azizi Q., Rahimi M., Mohammadi H., Khoshakhlagh F. 2016. Natural geography researches. 49: 381-393.
- Bhuyan M., Islam M. and Bhuiyan M. 2018. A trend analysis of temperature and rainfall to predict climate change for northwestern region of Bangladesh. American Journal of Climate Change. 7: 115-134.
- Dini G., Zieaean P., Alimohammadi A., and Dadashi S. 2008. GIS-Based Snow Mapping in Central Alborz Mountain Chain Using MODIS and AVHRR Data. Iran-Water Resources Research, 3: 1-8 (In Persian).
Fassnacht S., Cherry M., Venable N., and Saavedra F. 2016. Snow and albedo climate change impacts across the United States Northern Great Plains. The Cryosphere, 10: 329–339.
- Fatahi A., and Moghimi Sh. 2018. The effect of climate change on the snow trend in northwest Iran. Applied Research of Geographical Sciences, 54:47-63 (In Persian).
- Ghasemi A.R. 2015. Changes and trends in maximum, minimum and mean temperature series in Iran. Atmospheric Science Letters.16: 366-372.
- Ghorbanzadeh H., Sedki H., Thaqfian B., and Parhamat J. 2018. Investigating the effect of climate change on the time of maximum runoff flow caused by snow melting. Iran-Watershed Management Science & Engineering. 9: 23-36. (In Persian).
- Haqizadeh A., and Arshiya A. 2017. Investigation and monitoring of snow level changes in Chaharmahal Bakhtiari province. Journal of Extension and Development of Watershed Management, 21: 20-11 (In Persian).
- Husler F., Jonas T., Wunderle S., and Albrecht S. 2012. Validation of a modified snow cover retrieval algorithm from historical 1-km AVHRR data over the European Alps. Remote Sensing of Environment, 121: 497–515.
- Masoudian A., and Keikhosravi M. 2019. Analyzing the changes in the beginning of the snow cover accumulation season in Iran using remote sensing data. Geography and environmental planning: 1-14 (In Persian).
- Mazidi A., Mozaffari G., and Omidi Sh. 2021. Analyzing changes in the snow cover of Dana heights using remote sensing. 5th International Congress of Developing Agriculture, Natural Resources, Environment and Tourism of Iran, 1-7. 23 September 2021. Iran, Tabriz (In Persian).
- Mohammad Ibrahim H., Sadat F., and Thaqfian b. 2013. Snow level monitoring of Shah Cheraghi dam basin using NOAA-AVHRR images. Natural Geography Research, 45: 13-29 (In Persian).
- Poggio L., and Gimona A. 2015. Sequence-based mapping approach to spatiotemporal snow patterns from MODIS time-series applied to Scotland. International Journal of Applied Earth Observation and Geo-information, 34:122–135.
- Serrano A., Mateos V.L., and Garcia J.A. 1999. Trend Analysis of Monthly Precipitation over the Iberian Peninsula for the Period 1921-1995. Physics Chemistry of Earth, 24: 85- 90.
- Solaimani K., Shadman D., Shokrian F., and Rashidpou M. 2018. Monitoring of temporal-spatial variations of snow cover using the MODIS image (Case Study: Kurdistan Province). Iranian remote sensing and GIS. 10: 77-104 (In Persian).
- Tasdighian M., and Rahimzadegan M. 2017.Evaluation and improvement of snow cover detection from MODIS images. Iran-Water Resources Research. 13: 163-177.
- Yaghmai L., Jafari R., Soltani S., and Jahanbazi H. 2021. The effect of surface changes and the durability of snow cover on vegetation in Chaharmahal and Bakhtiari province. Pasture and Watershed. 74: 917-938 (In Persian).
- Yan D., Huang C., Ma N., and Zhang Y. 2020. Improved Landsat-Based Water And Snow Indices For Extracting Lake And Snow Cover/Glacier In The Tibetan Plateau. JournalWater. 12: 1-16.
- Yarahmadi D., Fathnia A., and Sharaft M. 2019. Evaluation of snow line temperature and identification of areas with snow fall potential in Alborz Mountains with pictures. NOAA-AVHRR. Applied Research in Geographical Sciences, 56: 193-204 (In Persian).
- Zarabi A., Halabian A., Shabankari M. 2006. Planning of inter-basin water transfer from Karun to Zayandeh Rood. Humanities Research Journal. 22: 67-84.
)