صحت سنجي تبخير و تعرق تخميني با الگوريتم بيلان انرژي در سطح زمين و اطلاعات سنجنده هاي OLI و TIRS

Verification of Estimated Evapotranspiration by Surface Energy Balance Algorithm for Land and the information of OLI and TIRS sensors

ﺨﻤﯿﻦ درﺳﺖ ﺗﻮزﯾﻊ ﻣﮑﺎﻧﯽ ﺗﺒﺨﯿﺮ ﺗﻌﺮق واﻗﻌﯽ )ET( روزاﻧﻪ، ﻣﻮﺟﺐ ارﺗﻘﺎء ﮐﺎراﺋﯽ ﻣﺪﯾﺮﯾﺖ ﻣﻨﺎﺑﻊ آب ﺑﻪﺧﺼﻮص در ﻣﻨﺎﻃﻘﯽ ﮐﻪ ﺑﺎ ﻣﺤﺪودﯾﺖ اﯾﻦ ﻣﻨﺎﺑﻊ ﻣﻮاﺟﻬﻨﺪ، ﻣﯽﺷﻮد. در ﭘﮋوﻫﺶ ﺣﺎﺿﺮ، ET ﺑﺎ اﺳﺘﻔﺎده از اﻟﮕﻮرﯾﺘﻢ ﺑﯿﻼن اﻧﺮژي در ﺳﻄﺢ زﻣﯿﻦ )SEBAL( و ﻣﺪل ﺗﺠﺮﺑﯽ ﻓﺎﺋﻮ-ﭘﻨﻤﻦ-ﻣﺎﻧﺘﯿﺚ )FPM( ﺑﺮآورد و ﺳﭙﺲ ﺑﺎ ﻣﻘﺎدﯾﺮ ﺑﻪدﺳﺖ آﻣﺪه از روش ﺗﺸﺖ ﺗﺒﺨﯿﺮ، ﻣﻘﺎﯾﺴﻪ و ﺻﺤﺖﺳﻨﺠﯽ ﺷﺪ. از آنﺟﺎ ﮐﻪ ﻋﻮاﻣﻞ ﻣﺨﺘﻠﻔﯽ ﺑﺮ ﻣﻘﺎدﯾﺮ ET ﺗﺄﺛﯿﺮﮔﺬارﻧﺪ، در ﻧﻬﺎﯾﺖ، ﺑﺎ اﻧﺠﺎم ﺗﺤﻠﯿﻞ ﺣﺴﺎﺳﯿﺖ، ﻣﯿﺰان ﺣﺴﺎﺳﯿﺖ ﻣﻘﺎدﯾﺮ ET اﻟﮕﻮرﯾﺘﻢ SEBAL ﻧﺴﺒﺖ ﺑﻪ ﺗﻐﯿﯿﺮ ﭘﺎراﻣﺘﺮﻫﺎي ورودي، ﺑﺮرﺳﯽ ﺷﺪ. در اﯾﻦ راﺳﺘﺎ، اﻟﮕﻮرﯾﺘﻢ SEBAL ﺑﺎ اﺳﺘﻔﺎده از دادهﻫﺎي ﻣﺎﻫﻮاره Landsat8 )ﺳﻨﺠﻨﺪه OLI و TIRS( در ﻣﻘﯿﺎس روزاﻧﻪ ﺑﺮاي دوره زﻣﺎﻧﯽ 2018/7/25 ﺗﺎ 2018/9/11 اﺟﺮا ﺷﺪ. ﻧﺘﺎﯾﺞ SEBAL ﻧﺸﺎن داد ﮐﻪ ﻣﻘﺎدﯾﺮ ﺷﺎﺧﺺﻫﺎي R2 ،RMSE ،SEE، ﻧﺴﺒﺖ ﺑﻪ اندازه گيري هاي تشت تبخير به ترتيب برابر 1.27, 0.76 , 0.77 ميلي متر بر روز و براي روش تجربي FPMبه ترتيب برابر با0.91, 0.6 , 0.92 ميلي متر بر روز است.

The accurate estimation of daily Evapotranspiration (ET) improves the efficiency of water resources management especially in areas where suffers from water scarcity. In the present study, ET was estimated using surface energy balance algorithm for land (SEBAL) and the experimental model of FAO-Penman-Monteith (FPM) and finally compared and verified with those calculated from pan evaporation method. Since many climatic factors affect the ET values, the sensitivity analysis of SEBAL inputs variables was finally cerried out to determine the key affecting parameters. In this regard, by SEBAL model and emplying the satellite data of Landsat 8 (OLI and TIRS sensors), the ET values were estimated on a daily scale for the time period 2018/07/25 to 2018/09/11. Results of SEBAL model showed that the values of SEE, RMSE and R2 indices were equal to 1.27, 0.76 and 0.77 mm /day and 0.91, 0.6 and 0.92 mm /day, while compared with those of FPM and pan evaporation methods, respectively.