توسعه یک چارچوب ریز مقیاس ‌سازی به ‌منظور برآورد تبخیر-تعرق مرجع زیرروزانه: 2- برآورد تبخیر- تعرق زیرروزانه با استفاده از داده‌های هواشناسی روزانه ‌ریزمقیاس شده

نوع مقاله : مقالات پژوهشی

نویسندگان

1 دانشگاه تربیت مدرس

2 دانشگاه شهرکرد

3 دانشگاه گیلان

4 دانشگاه هرمزگان

چکیده

در کاربردهای مختلفی چون مدل‌سازی پویای زراعی-هیدرولوژیکی، نیاز به برآوردهای زیرروزانه تبخیر-تعرق مرجع (ETo) می‌باشد. با این حال، در بسیاری از مناطق، عدم دسترسی به داده‌های هواشناسی زیرروزانه مانع از کمّی‌سازی ETo زیرروزانه گردیده است. در این مقاله، ET o زیرروزانه با استفاده از مدل‌های پنمن-مانتیث ASCE و فائو 56 (به ‌ترتیب، ASCE-PM و FAO56-PM) و اطلاعات هواشناسی زیرروزانه حاصل از چارچوب ریزمقیاس‌سازی توسعه یافته برآورد گردید. بدین منظور، از اطلاعات هواشناسی بلندمدت روزانه ایستگاه‌های سینوپتیک آبادان (59 ساله) و اهواز (50 ساله) استفاده شد. نتایج حاکی از یک انطباق بسیار بالا بین مقادیر روزانه و برآوردهای مجموع 24 ساعته ETo اشتقاق یافته از مدل‌های ASCE-PM (با ضریب کارآیی مدل (EF) بین 990/0 تا 994/0) و FAO56-PM (با EF بین 992/0 تا 995/0) در مقیاس‌های زمانی مختلف بود. برآوردهای مجموع 24 ساعته ETo زیرروزانه ‌اشتقاق یافته از هر دو مدل ASCE-PM و FAO56-PM، مقادیر ETo روزانه در مناطق آبادان و اهواز را به ‌ترتیب، کم‌برآورد (به ‌ترتیب، 08/0 و 58/0 درصد) و بیش‌برآورد (به ‌ترتیب، 63/1 و 98/0 درصد) نمودند. عملکرد هر دو مدل فوق در بازسازی مقادیر روزانه مولفه آیرودینامیک، در مقایسه با مقادیر روزانه مولفه تشعشع بهتر بود. به‌طور کلی، با افزایش مقیاس زمانی، میزان انطباق بین مقادیر مجموع 24 ساعته ETo با مقادیر روزانه فاقد روندی مشخص بود. نتایج نشان داد اتخاذ گام زمانی کوچکتر، لزوما به بهبود انطباق مقادیر مجموع 24 ساعته و روزانه ETo نمی‌انجامد.

کلیدواژه‌ها


عنوان مقاله [English]

Development of a Disaggregation Framework toward the Estimation of Subdaily Reference Evapotranspiration: 2- Estimation of Subdaily Reference Evapotranspiration Using Disaggregated Weather Data

نویسندگان [English]

  • F. Parchami Araghi 1
  • seyed majid mirlatifi 1
  • Sh. Ghorbani Dashtaki 2
  • M. Vazifehdoust 3
  • A. Sadeghi Lari 4
1 Tarbiat Modares University
2 ShahreKord University
3 Guilan University
4 Hormozgan University
چکیده [English]

Introduction: Subdaily estimates of reference evapotranspiration (ET o) are needed in many applications such as dynamic agro-hydrological modeling. However, in many regions, the lack of subdaily weather data availability has hampered the efforts to quantify the subdaily ET o. In the first presented paper, a physically based framework was developed to desegregate daily weather data needed for estimation of subdaily reference ET o, including air temperature, wind speed, dew point, actual vapour pressure, relative humidity, and solar radiation. The main purpose of this study was to estimate the subdaily ETo using disaggregated daily data derived from developed disaggregation framework in the first presented paper.
Materials and Methods: Subdaily ET o estimates were made, using ASCE and FAO-56 Penman–Monteith models (ASCE-PM and FAO56-PM, respectively) and subdaily weather data derived from the developed daily-to-subdaily weather data disaggregation framework. To this end, long-term daily weather data got from Abadan (59 years) and Ahvaz (50 years) synoptic weather stations were collected. Sensitivity analysis of Penman–Monteith model to the different meteorological variables (including, daily air temperature, wind speed at 2 m height, actual vapor pressure, and solar radiation) was carried out, using partial derivatives of Penman–Monteith equation. The capability of the two models for retrieving the daily ETo was evaluated, using root mean square error RMSE (mm), the mean error ME (mm), the mean absolute error ME (mm), Pearson correlation coefficient r (-), and Nash–Sutcliffe model efficiency coefficient EF (-). Different contributions to the overall error were decomposed using a regression-based method.
Results and Discussion: The results of the sensitivity analysis showed that the daily air temperature and the actual vapor pressure are the most significant meteorological variables, which affect the ETo estimates. In contrast, low sensitivity coefficients got for wind speed and the solar radiation. The similar patterns of ETo sensitivity coefficient to the air temperature ( ) and the air temperature (TA) showed that the extent of the seasonal variation of was mainly determined by the TA. Results showed a good agreement between daily and 24h sum of subdaily ETo derived from ASCE-PM (with an EF of 0.990 to 0.994) and FAO56-PM (with an EF of 0.992 to 0.995) models. The results showed a good generalization capability of the disaggregation models to estimate the subdaily ETo for the validation data set (Ahvaz). The 24h sum of subdaily ETo derived from both models underestimated and overestimated the daily ETo in calibration (Abadan) and validation (Ahvaz) data sets, respectively. In case of both models, the daily values of aerodynamic component of ETo were reproduced more efficiently, compared to radiation part. In case of the FAO56-PM model, the goodness of agreement between 24h sum of subdaily and daily values of aerodynamic part of the ETo showed a low sensitivity to variation of the time scale of weather data. With the increase of the time scale of the subdaily weather data, the ability of both models in retrieving the radiation component of the daily ETo was improved. Generally, there was no apparent relationship between the efficiency of the ASCE-PM and FAO56-PM models for retrieving the daily ETo and the time scale of weather data. Results showed that adoption of a smaller time step does not always leads to an improvement in the agreement between 24h sum of subdaily and daily values of ETo. For most of the studied subdaily time scales (1 to 360 min), the FAO56-PM model had better performance in retrieving the daily ETo, compared to the ASCE-PM model.
Conclusion: The results of this study showed that the developed disagregation framework was able to estimate the subdaily ET o. In this study, the promising results got in retrieving the daily ETo can be attributed mainly to the high sensitivity of ETo to the air temperature and actual vapor pressure (which were desegregated with a reasonable accuracy) and low sensitivity to the wind speed (which were desegregated with a low accuracy) and the solar radiation (which were disaggregated with a reasonable accuracy). The main reason for the absence of an apparent relationship apparent relationship between the efficiency of the ASCE-PM and FAO56-PM models for retrieving the daily ETo and the time scale of weather data can be attributed to adopted nighttime and daytime criteria in both models which is highly affected by time-scale of weather data and the estimated net long wave radiation.

کلیدواژه‌ها [English]

  • Canopy Resistance
  • Penman–Monteith
1- Allen R.G., Pereira L.S., Raes D., and Smith M. 1998. Crop evapotranspiration: Guidelines for computing crop water requirements. FAO irrigation and drainage paper 56, FAO, Rome, Italy, 301 pp.
2- Allen R.G., Pruitt W.O., Businger J.A., Fritschen L.J., Jensen M.E., and Quinn F.H. 1996. Evaporation and transpiration. In: Heggen R.J. (Ed.), ASCE Handbook of Hydrology. American Society of Civil Engineers, New York.
3- Allen R.G., Walter I.A., Elliott R.L., Howell T.A., Itenfisu D., Jensen M.E., and Snyder R.L. 2005. The ASCE standardized reference evapotranspiration equation. American Society of Civil Engineers, Reston, Virginia, 192 pp.
4- Bakhtiari B., Khalili A., Liaghat A.M., and Khanjani M.J. 2009. Comparison of Daily with Sum-of-Hourly Reference Evapotranspiration in Kerman Reference Weather Station. Journal of Water and Soil, 23(1): 45-56. (in Persian with English abstract).
5- Beven K.J. 1979. A sensitivity analysis of the Penman-Monteith actual evapotranspiration estimates. Journal of Hydrology, 44(3): 169-190.
6- Blaney H.F., and Criddle W.D. 1950. Determining Water Requirements in Irrigated Area from Climatological Irrigation Data, US Department of Agriculture. Department of Agriculture, Soil Conservation Service, Techical Paper No. 96.
7- Gauch H.G., Hwang J.T., and Fick G.W. 2003. Model evaluation by comparison of model-based predictions and measured values. Agronomy Journal, 95(6): 1442-1446.
8- Gong L., Xu C., Chen D., Halldin S., and Chen Y.D. 2006. Sensitivity of the Penman–Monteith reference evapotranspiration to key climatic variables in the Changjiang (Yangtze River) basin. Journal of Hydrology, 329(3): 620-629.
9- Guitjens J.C. 1982. Models of Alfalfa Yield and Evapotranspiration. Journal of the Irrigation and Drainage Division, Proceedings of the American Society of Civil Engineers, 108(IR3): 212– 222.
10- Harbeck J.G.E. 1962. A Practical Field Technique for Measuring Reservoir Evaporation Utilizing Mass-transfer Theory. US Geological Survey, Paper 272-E, pp. 101–105.
11- Lopez-Urrea R., Olalla F., Fabeiro C., and Moratalla A. 2006. An evaluation of two hourly reference evapotranspiration equations for semiarid conditions. Agricultural water management, 86(3): 277-282.
12- Parchami-Araghi F., Mirlatifi S.M., Ghorbani Dashtaki S., and Mahdian M.H. 2013. Point estimation of soil water infiltration process using Artificial Neural Networks for some calcareous soils. Journal of Hydrology, 481: 35-47.
13- Parchami-Araghi F., Mirlatifi S.M., Ghorbani Dashtaki S., Vazifehdoust M., and Sadeghi-Lari A. 2015. Development of a Disaggregation Framework toward the Estimation of Subdaily Reference Evapotranspiration: 1- Performance Comparison of Some Daily-to-subdaily Weather Data Disaggregation Models. Journal of Water and Soil, Accepted (in Persian with English abstract).
14- Penman H.L. 1948. evaporation from open water, bare soil and grass. Proceedings of the Royal Society of London, 193: 120–145.
15- Priestley C.H.B., and Taylor R.J. 1972. On the assessment of surface heat flux and evaporation using large-scale parameters. Monthly weather review, 100(2): 81-92.
16- Shirmohammadi Z., Ansari H., and Alizadeh A. 2011. A Comparison of ASCE and FAO-56 Reference Evapotranspiration for a Hourly Time Step in Fariman Weather Station. Journal of Water and Soil, 25(3): 472-484. (in Persian with English abstract).
17- Steduto P., Todorovic M., Caliandro A., and Rubino P. 2003. Daily ETo estimates by the Penman-Monteith equation in southern Italy: Constant vs. variable canopy resistance. Theoretical and Applied Climatology, 74(3): 217-225.
18- Suleiman A.A., and Hoogenboom G. 2009. A comparison of ASCE and FAO-56 reference evapotranspiration for a 15-min time step in humid climate conditions. Journal of hydrology, 375(3): 326-333.
19- Thornthwaite C.W. 1948. An approach toward a rational classification of climate. Geographical Review, 38: 55–94.
20- Todorovic M. 1999. Single-layer evapotranspiration model with variable canopy resistance. Journal of Irrigation and Drainage Engineering, 125(5): 235-245.
21- Ventura F., Spano D., Duce P., and Snyder R.L. 1999. An evaluation of common evapotranspiration equations. Irrigation Science, 18(4): 163-170.
22- Zeng W., and Heilman J.L. 1997. Sensitivity of evapotranspiration of cotton and sorghum in west Texas to changes in climate and CO2. Theoretical and Applied Climatology, 57(3-4): 245-254.
CAPTCHA Image