تعیین میزان همبستگی بین شاخص‌های پوشش گیاهی NDVI و EVI با شاخص خشکسالی هواشناسی SPI (مطالعه موردی: مراتع دشتی استان گلستان)

نوع مقاله : مقاله پژوهشی

نویسندگان

1 استادیار گروه مرتع و آبخیزداری، دانشکده منابع طبیعی و محیط زیست، دانشگاه ملایر

2 دانش‌آموخته کارشناسی ارشد منابع طبیعی- مرتعداری، دانشگاه علوم کشاورزی و منابع طبیعی گرگان

3 استاد گروه مرتع و آبخیزداری، دانشگاه علوم کشاورزی و منابع طبیعی گرگان

چکیده

در این تحقیق ارتباط بین شاخص بارش استاندارد (SPI) سالانه با شاخص پوشش گیاهی بارزسازی شده (EVI) و شاخص تفاضل نرمال شده پوشش گیاهی (NDVI) و نیز میزان تشخیص تغییرات پوشش گیاهی توسط دو شاخص NDVI و EVI با روش تفریق تصویر مورد بررسی قرار گرفت. بدین منظور داده­های بارندگی ایستگاه‌­های موجود در 5 ایستگاه در مراتع دشتی استان گلستان از آغاز تاسیس تا سال 1393 و تصاویر سنجنده MODIS در طول سال­های 2000 تا 2012 در  فصل رویش پوشش گیاهی مراتع استان گلستان جمع آوری گردید. جهت تعیین میزان همبستگی بین شاخص خشکسالی و شاخص های سنجش از دور از ضریب همبستگی پیرسون استفاده شد. نتایج نشان داد که میزان همبستگی بین شاخص خشکسالی SPI با EVI و NDVI به ترتیب برابر با 75/0 و 78/0  و میزان همبستگی در تشخیص تغییرات پوشش گیاهی دو شاخص NDVI و EVI برابر با 98/0 است که در سطح 05/0 معنی­دار می­باشد. به طور کلی نتایج این تحقیق نشان داد که در مناطقی با داده­های باران سنجی ناکافی و پراکنش نامناسب برای پایش خشکسالی می­توان از  داده های سنجش از دور . همچنین شاخص­های پوشش گیاهی NDVI و EVI برای تشخیص تغییرات پوشش گیاهی مناسب می باشند.

کلیدواژه‌ها


عنوان مقاله [English]

Determining the correlation between NDVI and EVI vegetation indices and SPI drought index (Case Study: Golestan rangelands)

نویسندگان [English]

  • B. Farrokhzadeh 1
  • Sh. Mansouri 2
  • A. Sepehri 3
1 Assistant Professor, Department of Range and watershed management, Malayer University
2 M. Sc. Graduate of Watershed Management, Gorgan University
3 Assistant Professor, Department of Range and watershed management, Gorgan University
چکیده [English]

In this study the relationship between annual Standard Precipitation Index (SPI) and, remotely sensed indices of Enhanced Vegetation Index (EVI) and Normalized Differencing Vegetation Index (NDVI) have been studied.  MODIS images of Terra satellites for the period of 2000 to 2012, during the growing season of pastures across Golestan province alongwith rainfall data of five meteorological stations in Golestan rangelands from their establishment till 1993 were collected. Pearson correlation coefficient was used to assess the relationship between rainfall data and vegetations indices. Correlation coefficient between (SPI) drought index and EVI and NDVI indices was 0.75 and 0.78 respectively at 5% level of significance. Bedsides, correlation between the NDVI and EVI indices in detection of the vegetation changes were 0.98. In general, the results of this study showed that in regions with inadequate rainfall data, remote sensing products can be used for drought and vegetation cover dynamic monitoring.
 

کلیدواژه‌ها [English]

  • Drought
  • Standard Precipitation Index
  • MODIS
  • Golestan province
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