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Estimation of Evapotranspiration of Palmyra Oasis by Energy Balance method «Analaitical and Experemental Study»

تقدير الانفضاج التبخري لواحة تدمر بطريقة موازنة الطاقة «دراسة تحليلية و تجريبية»

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 Publication date 2004
and research's language is العربية
 Created by Shamra Editor




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Continuous calculations of evapotranspiration (LE) using eddy covariance method and energy budget were performed over more than one year above the heterogeneous canopy of an arid oasis ecosystem in the central Syrian desert. Irrigation practice was traditional flooding with a 28 days turn of water delivery. The work focuses on seasonal variations of energy budget over a 2 years period with emphasis on effects of rainfall, wind speed and radiative budget on evapotranspiration. Maximum evapotranspiration was only 5mm/day. Even under irrigation practices, winter rainfall seems to have an important impact on LE: comparisons of two situations in June 2002 and June 2003 showed an increase of 13% in values of LE/Rn-G. Maximum averaged hourly values of evapotranspiration were found for wind speed values closed to 3m/s. This suggests that when the evaporative demand from the air (or vapour pressure deficit (vpd) ) is increasing above a certain limit, the vegetation closes its stomata and reduces transpiration. Results from the energy balance closure showed significant differences in the slope of H+LE against Rn-G relationships between cold and hot month which was explained by specific radiative budget of desert areas.


Artificial intelligence review:
Research summary
تتناول هذه الدراسة تقدير التبخر-نتح في واحة تدمر باستخدام طريقة توازن الطاقة. تم إجراء حسابات مستمرة للتبخر-نتح باستخدام طريقة التباين الدوامي وميزانية الطاقة على مدار أكثر من عام فوق مظلة غير متجانسة في نظام بيئي صحراوي في وسط سوريا. كانت ممارسات الري تقليدية باستخدام الفيضانات مع دورة تسليم المياه كل 28 يومًا. ركزت الدراسة على التغيرات الموسمية في ميزانية الطاقة على مدى عامين مع التركيز على تأثيرات هطول الأمطار وسرعة الرياح والميزانية الإشعاعية على التبخر-نتح. تم العثور على الحد الأقصى للتبخر-نتح ليكون 5 مم/يوم. حتى مع ممارسات الري، يبدو أن هطول الأمطار الشتوي له تأثير كبير على التبخر-نتح، حيث أظهرت المقارنات بين يونيو 2002 ويونيو 2003 زيادة بنسبة 13% في قيم LE/Rn-G. تم العثور على أعلى متوسطات لقيم التبخر-نتح عند سرعات الرياح القريبة من 3 م/ث، مما يشير إلى أن النبات يغلق مساماته ويقلل من التبخر عندما يزيد الطلب التبخيري من الهواء (أو عجز ضغط البخار) فوق حد معين. أظهرت نتائج إغلاق ميزانية الطاقة اختلافات كبيرة في ميل علاقات H+LE مقابل Rn-G بين الأشهر الباردة والحارة، والتي تم تفسيرها بواسطة الميزانية الإشعاعية الخاصة بالمناطق الصحراوية.
Critical review
دراسة نقدية: تعتبر هذه الدراسة مهمة لفهم ديناميكيات التبخر-نتح في البيئات الصحراوية، وهي تقدم رؤى قيمة حول تأثير العوامل البيئية المختلفة على هذه العملية. ومع ذلك، يمكن تحسين الدراسة من خلال تضمين مزيد من التفاصيل حول المنهجية المستخدمة في جمع البيانات وتحليلها، بالإضافة إلى مناقشة أوسع للقيود المحتملة للدراسة وكيفية التغلب عليها في الأبحاث المستقبلية. كما أن استخدام تقنيات حديثة مثل النمذجة الحاسوبية قد يضيف قيمة إضافية للنتائج ويساعد في تعميمها على مناطق أخرى مشابهة.
Questions related to the research
  1. ما هي الطريقة المستخدمة في الدراسة لحساب التبخر-نتح؟

    تم استخدام طريقة التباين الدوامي وميزانية الطاقة لحساب التبخر-نتح.

  2. ما هو الحد الأقصى للتبخر-نتح الذي تم العثور عليه في الدراسة؟

    الحد الأقصى للتبخر-نتح الذي تم العثور عليه هو 5 مم/يوم.

  3. ما هو تأثير هطول الأمطار الشتوي على التبخر-نتح في الدراسة؟

    هطول الأمطار الشتوي له تأثير كبير على التبخر-نتح، حيث أظهرت المقارنات زيادة بنسبة 13% في قيم LE/Rn-G.

  4. ما هي العلاقة بين سرعة الرياح والتبخر-نتح وفقًا للدراسة؟

    تم العثور على أعلى متوسطات لقيم التبخر-نتح عند سرعات الرياح القريبة من 3 م/ث، مما يشير إلى أن النبات يغلق مساماته ويقلل من التبخر عندما يزيد الطلب التبخيري من الهواء فوق حد معين.


References used
ANTHONI, P., LAW, B.E., UNSWORTH, M.J., VONG, R.J., 2000. Variation in net radiation over heterogeneous surfaces: measurements and simulations in a juniper-sagebrush ecosystem. Agricultural and Forest Meteorology, 102: 275-286
BLANEY, H.F., CRIDDLE, W.D., 1962. Determining consumptive use and irrigation water requirements. USDA (ARS) technical Bulletin, 1275, 59pp
BRUTSAERT, W., 1982. Evaporation into the Atmosphere, D. Reidel Publishing company, Holland, 299 pp
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