برآورد مساحت آتش‌سوزی در پوشش‌های گیاهی ایران با استفاده از داده‌های سنجندة مودیس و ‌آلوس‌– 2

نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانشجوی کارشناسی ارشد سنجش از دور و GIS، دانشکدة جغرافیا، دانشگاه تهران

2 دانشجوی کارشناسی ارشد سنجش از دور و GIS، دانشکدة جغرافیا، دانشگاه یزد

چکیده

آتش‌سوزی در پوشش‌های جنگلی سطح جهان باعث واردشدن خسارات شدید به پوشش‌های گیاهی، خاک و زیستگاه‌های طبیعی می‌شود که تأثیرات زیست‌محیطی منفی مستقیم و غیرمستقیم را به‌همراه دارد؛ ازجمله جنگل‌زدایی، تغییرات آب‌وهوا و خشکسالی. ازاین‌رو تشخیص و تعیین خطرها، برای پوشش‌های گیاهی که دچار آتش‌سوزی می‌شوند، به‌منظور مدیریت و توسعة آنها بسیار مهم است. گسترش تصاویر سنجش از دوری، همچون محصولات آتش فعال دو ماهوارة ترا (Terra) و آکوا (Aqua)، طی دو دهة گذشته، از روش‌های مهم در تشخیص این آتش‌سوزی‌ها بوده است. بااین‌حال محصول آتش فعال سنجندة مودیس، طی مطالعات گذشته، نشان داده است که این موارد به‌تنهایی نتایج مناسبی از مناطق تحت تأثیر آتش به‌دست نمی‌دهند. ازاین‌رو نیاز است با نقشه‌های پایة پوشش‌های گیاهی ارزیابی شوند. این تحقیق با هدف بررسی دو نوع محصولات گیاهی و کشف آتش فعال سنجندة مودیس و نقشة پوشش‌های جنگلی و غیرجنگلی FNF-JAXA، برای تفکیک بهتر مناطقی که دچار آتش‌سوزی شده‌اند، در پوشش‌های گیاهی کشور ایران بین روزهای ژولیوسی 1 تا 160 (یازدهم دی 1398 تا هجدهم خرداد 1399) در سال 2020 انجام شد. نتایج بیانگر بیشترین مساحت آتش‌سوزی در روز ژولیوسی 144 (سوم خرداد 1399)، با بیش‌از 49هزار هکتار و روز ژولیوسی 128 (هجدهم اردیبهشت 1399)، با بیش‌از 45هزار هکتار است. اما بیشترین مساحت آتش‌سوزی‌ پوشش‌های جنگلی در روزهای 120 تا 160 (دهم اردیبهشت تا هجدهم خرداد 1399)، با بیش‌از 14هزار هکتار برآورد شده است. استان خوزستان بیشترین مساحت آتش‌سوزی را در دورة زمانی مورد مطالعه، داشته است که بیشتر این مناطق در اراضی کشاورزی قرار داشتند. سه استان فارس، کهگیلویه و بویراحمد و بوشهر بیشترین مساحت آتش‌سوزی‌ها را در پوشش‌های جنگلی داشته‌اند. بیشترین فراوانی آتش‌سوزی‌ها در اراضی کشاورزی مشاهده شد که مهم‌ترین دلایل آن می‌تواند دخالت‌های انسانی باشد. همچنین ارزیابی نهایی نتایج نشان داد استفاده از محصول FNF-JAXA (با صحت نهایی 4/87% و ضریب کاپای 85/0)، در قیاس با محصولات مودیس (با صحت نهایی3/80% و ضریب کاپای 78/0)، در تفکیک مناطق جنگلی قابلیت بهتری دارد. بااین‌همه توانایی محصولات مودیس در تفکیک نوع پوشش گیاهی مرتع و کشاورزی مزیتی مهم به‌شمار می‌رود که محصول FNF-JAXA چنین ویژگی‌ای ندارد. به‌‌طور کلی، یافته‌های تحقیق بیانگر قابلیت مناسب تصاویر محصولات گیاهی مودیس و نقشه‌های FNF-JAXA است که می‌توانند، به‌منزلة نقشه‌های مرجع برای تفکیک پوشش‌های گیاهی گوناگون که دچار آتش‌سوزی می‌شوند، در ارزیابی خسارت و مدیریت آنها به‌کار روند.

کلیدواژه‌ها


عنوان مقاله [English]

Estimation of Fire Area in Iranian Vegetation Using MODIS and Alos-2 Data

نویسندگان [English]

  • morteza Sharif 1
  • aboozar kiani 2
1 M.Sc. Student of Remote Sensing and GIS, Faculty of Geography, University of Tehran
2 M.Sc. Student of Remote Sensing and GIS, Faculty of Geography, University of Yazd
چکیده [English]

Forest fires worldwide cause severe damage to vegetation, soil and natural habitats, resulting in direct and indirect negative environmental impacts such as deforestation, climate change and drought. Therefore, identifying and determining the hazards of vegetation that suffer from fire is crucial for their management and development. The proliferation of remote sensing images such as the active fire products of the Terra and Aqua satellites over the past two decades has been one of the most essential methods in detecting these fires. However, the active fire product of the MODIS sensor in previous studies has shown that they alone do not provide good results in fire-affected areas. Therefore, it is necessary to evaluate vegetation with basic maps. The aim of this study was to investigate two types of plant products and to discover the active fire of MODIS sensor and FNF-JAXA forest and non-forest cover maps for better separation of burnt areas of vegetation in Iran between July 1 and 160 2020. The results show the highest area of fire on Julius 144 with more than 49 thousand hectares and Julius 128 with more than 45 thousand hectares. However, the largest area of the fire, forest cover is estimated at 120 to 160 in 2020 with more than 14 thousand hectares. Khuzestan province had the highest area of fires in the period under study that most of these areas in agricultural lands and the three provinces of Fars, Kohgiluyeh and Boyer-Ahmad and Bushehr had the highest area of fires in forest cover. The highest frequency of fires was observed in agricultural lands, the main reason for which could be human intervention. The evaluation of the results showed that the use of the FNF-JAXA product (accuracy of 87.4% and a Kappa coefficient of 0.85) compared to MODIS products (accuracy of 80.3% and a Kappa coefficient of 0.78) in the separation of forest areas has better capabilities. However, the ability of MODIS products to distinguish between pasture and agricultural vegetation is an important advantage, which the FNF-JAXA product does not have. In general, the findings of the research show that the MODIS product and FNF-JAXA maps can be used as reference maps to distinguish different types of vegetation that are subject to fire, in damage assessment and management.

کلیدواژه‌ها [English]

  • Active fire products
  • Forest
  • Drought
  • Terra
  • FNF-JAXA
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