ارزیابی الگوریتم سنجش از دور SEBAL در برآورد تبخیر و تعرق واقعی در کاربری‌های مختلف (مطالعه موردی: حوضه دریاچه ارومیه)

نویسندگان

چکیده

تبخیر و تعرق واقعی یکی از مهم‌ترین عامل‌های مؤثر بر مدیریت آب بخش کشاورزی است که برآورد آن به‌ویژه در سطح‌های وسیع،‏ مشکلات اجرایی خاص خود را دارد. در دهه‌های اخیر بررسی‌های زیادی در زمینه برآورد این متغیر با فناوری سنجش از دور انجام شده که بیشتر بر مبنای بیلان انرژی سطح زمین استوار هستند. از مطرح‌ترین الگوریتم‌ها در این زمینه،‏ SEBAL است که پیاده‌سازی آن نیاز به شناخت قابلیت‌ها و کارآیی آن در کاربری‌های مختلف است. هدف مهم حاضر این است که با به‌کارگیری الگوریتم SEBAL و تصاویر‌های ماهواره Terra (سنجنده MODIS)‎ برای دوره زمانی 2002 تا 2008،‏ مقادیر تبخیر و تعرق واقعی به صورت ماهانه برآورد شود. منطقه مطالعاتی حوضه دریاچه ارومیه است که با توجه به تنوع کاربری آن،‏ مقدار تبخیر و تعرق واقعی به‌صورت مجزا برای کاربری‌های مختلف شامل کشت‌های آبی،‏ دیم،‏ شوره‌زارها و پیکره‌های آبی برآورد شد. نتایج پژوهش و مقایسه با مقادیر مشاهداتی،‏ نشان از دقت مناسب مدل در زمین‌های کشاورزی آبی (ضریب تبیین 84‎/0) و همچنین پیکره‌های آبی (ضریب تبیین 84‎/0) دارد اما در شوره‌زارها،‏ زمین‌های دیم و مراتع مدل با ضعف روبروست.

کلیدواژه‌ها


عنوان مقاله [English]

Assessment of -- ote sensing SEBAL algorithm to estimate actual evapotranspiration from different land uses (Case study: Urmia Lake basin)

نویسندگان [English]

  • Saeid Morid
  • Mohammad Hossein Bagheri Haruni
  • Saleh Arshad
چکیده [English]

Actual evapotranspiration (ETa) is one of the important factors for agricultural water management. However, its estimation is not easy, especially in vast areas with different land uses. In the recent decades, many studies have been conducted for estimating Eta using remote sensing technology, which are mainly based on the surface energy balance concept. The SEBAL model is one of the well-known methods for this task. Nevertheless, application of such a model needs more insights about its capabilities, advantages and weaknesses. In this study, the SEBAL algorithm was applied to estimate monthly ETa using images of the Terra satellite (MODIS sensor) for the period of 2002 to 2008. The Urmia Lake basin is selected as the study area, which has a variety of land uses, including agriculture lands, water bodies and salty areas. The results revealed an acceptable agreement between estimated values of ETa and observed values in irrigated areas (R2= 0.84) and water bodies (R2= 0.84). But, the performance of SEBAL in the cases of the salty area, dry farming and grasslands was not enough good.Actual evapotranspiration (ETa) is one of the important factors for agricultural water management. However, its estimation is not easy, especially in vast areas with different land uses. In the recent decades, many studies have been conducted for estimating Eta using remote sensing technology, which are mainly based on the surface energy balance concept. The SEBAL model is one of the well-known methods for this task. Nevertheless, application of such a model needs more insights about its capabilities, advantages and weaknesses. In this study, the SEBAL algorithm was applied to estimate monthly ETa using images of the Terra satellite (MODIS sensor) for the period of 2002 to 2008. The Urmia Lake basin is selected as the study area, which has a variety of land uses, including agriculture lands, water bodies and salty areas. The results revealed an acceptable agreement between estimated values of ETa and observed values in irrigated areas (R2= 0.84) and water bodies (R2= 0.84). But, the performance of SEBAL in the cases of the salty area, dry farming and grasslands was not enough good.Actual evapotranspiration (ETa) is one of the important factors for agricultural water management. However, its estimation is not easy, especially in vast areas with different land uses. In the recent decades, many studies have been conducted for estimating Eta using remote sensing technology, which are mainly based on the surface energy balance concept. The SEBAL model is one of the well-known methods for this task. Nevertheless, application of such a model needs more insights about its capabilities, advantages and weaknesses. In this study, the SEBAL algorithm was applied to estimate monthly ETa using images of the Terra satellite (MODIS sensor) for the period of 2002 to 2008. The Urmia Lake basin is selected as the study area, which has a variety of land uses, including agriculture lands, water bodies and salty areas. The results revealed an acceptable agreement between estimated values of ETa and observed values in irrigated areas (R2= 0.84) and water bodies (R2= 0.84). But, the performance of SEBAL in the cases of the salty area, dry farming and grasslands was not enough good.Actual evapotranspiration (ETa) is one of the important factors for agricultural water management. However, its estimation is not easy, especially in vast areas with different land uses. In the recent decades, many studies have been conducted for estimating Eta using remote sensing technology, which are mainly based on the surface energy balance concept. The SEBAL model is one of the well-known methods for this task. Nevertheless, application of such a model needs more insights about its capabilities, advantages and weaknesses. In this study, the SEBAL algorithm was applied to estimate monthly ETa using images of the Terra satellite (MODIS sensor) for the period of 2002 to 2008. The Urmia Lake basin is selected as the study area, which has a variety of land uses, including agriculture lands, water bodies and salty areas. The results revealed an acceptable agreement between estimated values of ETa and observed values in irrigated areas (R2= 0.84) and water bodies (R2= 0.84). But, the performance of SEBAL in the cases of the salty area, dry farming and grasslands was not enough good.