Estimation of Daily Net Radiation in the Urmia Lake Basin under Clear-Sky Conditions Based on MODIS Data

Document Type : Full length article


1 Graduate Student, Master in Watershed Management, Urmia University, Urmia, Iran

2 Associate Professor of Natural Resources, Department of Range and Watershed Management, Urmia University, Urmia, Iran

3 PhD in Watershed Management, University of Kashan, Kashan, Iran


Daily average net radiation (DANR) is necessary for hydrological modeling, water resources management and planning, in particular for prediction of daily evapotranspiration (ET). Recently, some remote sensing based methods have been developed at watershed and regional scales to help researchers estimate DANR and ER under both clear and cloudy conditions. DANR is a critical variable linking estimates of instantaneous latent heat flux (satellite overpass time) from energy balance based models. Radiation modeling based on ground or station data is actually point scale estimation. On the other hands, application of geostatistical methods to produce radiation maps at watershed scale is often associated with remarkable errors due to the limited number of stations. In this study, net daily radiation maps were created based on newly developed geometric radiation model based on land and atmospheric MODIS data in the Urmia Lake Basin (ULB) under clear-sky condition for four selected dates in 2006 and 2007.
Materials and Methods
 In this study, the ULB located in northwestern Iran was selected as the study area that extending in latitude from around 35.67° to 38.47° N and in longitude from around 44.22° to 47.89° E. The basin has an area of approximately 52700 square kilometers. This study attempts to estimate the DANR maps for four selected days under clear sky. Long et al. (2010) developed a geometric model considering slope and aspect effects to improve parameterization schemes to estimate daily average net shortwave radiation (Rns) and daily average net longwave radiation (Rnl). In present study, the same methodology employed a characteristics model (slope, azimuth and elevation) based on daily MODIS data products and the global ASTER DEM. The DANR is total of the daily net short wavelength radiation and daily net long wavelength radiation. Long wave radiation was estimated using MODIS products including surface albedo, Land Surface Temperature (LST), atmospheric temperature, pressure and emissivity. A four-observation based method using Terra-MODIS and Aqua-MODIS LST data was applied to estimate daily average LST in order to improve the accuracy of estimations of Rnl. In the study, we applied the 24-hour incoming direct solar radiation (Sin24) measurements of Tabriz and Urmia synoptic stations for validation. The RMSE and MAE measures were used for model evaluation. In addition, due to the lack of ground-based Rnl observations, we utilized the FAO (Penman) method to generate corresponding ground data for model validation.
Results and discussion
 In order to compare the amount of incoming Sin24 on flat and slope surface, the whole study area was assumed as a flat and the Sin24 maps were produced. The differences between Sin24 on flat (Sin24,s) and sloping surfaces (Sin24,f) were calculated for all pixels. The histogram plot or frequency of Sin24,s - Sin24,f quantity at different intervals of slope showed that by increasing in slope degree, the frequency of pixels at all slope classes becomes greater. This reflects the importance of the slope for estimating Sin24. In addition, the values of Sin24 at flat are higher than sloping surfaces especially for where slopes < 30 degree. Aspect is another influencing factor on the amount of receiving and absorbed radiation. The RMSE and MAE for observed and estimated Sin24 values were 30.29 and 19w.m-2, respectively. The models in average overestimate Sin24 about 10.5%. The results showed that the eastern and western aspects receive more daily net radiation during day and sunshine hours or day length has its impact on radiation. For Rnl estimates, the RMSE was 36w.m-2
In present study, the Sin24 was parameterized by taking into account the effect of terrain factors, such as slope, azimuth and elevation on direct solar radiation. The sunrise and sunset angles for a given sloping surface (pixel) are different in geometric radiation model. Results indicate that the model has the capability to characterize the variability in Sin24. The incoming solar radiation for flat surface is higher than sloping surface. We founded that southeast and southwest aspects receive greater net radiation. The DANR values decrease with an increase in elevation. The geometric model used in this research needs to be evaluated in different watersheds in Iran without data availability problem especially daily Rns, Rnl and LST measurements, a high number of meteorological stations with proper spatial distribution. This research was done under limited data in the ULB.


Main Subjects

بابایی‏حصار، س. (1391). ارزیابی مدل هیبرید در برآورد تابش خورشیدی در شرایط مختلف اقلیمی ایران، پایان‏نامة کارشناسی ارشد، دانشکدة منابع طبیعی، دانشگاه ارومیه.
حیدری، و. (1393). توسعة یک مدل سادة سنجش از دور تبخیر و تعرق و ارزیابی آن در حوضة آبریز دریاچة ارومیه، پایان‏نامة کارشناسی ارشد، دانشکدة منابع طبیعی، دانشگاه ارومیه.
سبزی‏پرور، ع. و شادمانی، م. (1390). تحلیل روند تبخیر و تعرق مرجع با استفاده از آزمون من‏کندال و اسپیرمن در مناطق خشک ایران، نشریة آب و خاک (علوم و صنایع کشاورزی)، 25: ۸۲۳ـ834.
صابری، پ.؛ رحیمی‏خوب، ع.؛ صابری، ف. و زبردست، س. (1388). برآورد تابش خورشیدی رسیده به زمین با استفاده از تصاویر سنجندة AVHRR ماهوارة نوا (مطالعة موردی: کرمانشاه)، سومین همایش ملی مدیریت شبکه‏های آبیاری و زهکشی، اهواز، دانشگاه شهید چمران، ص ۱۶۳ـ172.
عرفانیان، م. و بابایی، س. (1392). ارزیابی مدل هیبرید در تخمین تابش خورشیدی روزانه در تعدادی از ایستگاه‏های تابش‏سنجی ایران، مجلة آب و خاک، 27(۱): 158-168.
علیزاده، ا. و خلیلی، ن. (1387). تعیین ضرایب معادلة آنگسترم و توسعة یک معادلة رگرسیونی برآورد تابش خورشیدی (مطالعة موردی: منطقة مشهد)، مجلة آب و خاک، 23(۱): ۲۲۹ـ238.
موسوی بایگی، م.؛ اشرف ب. و میان‏آبادی، آ. (1389). بررسی مدل‏های مختلف برآورد تابش خورشیدی به منظور معرفی مناسب‏ترین مدل در یک اقلیم نیمه‏خشک، مجلة آب و خاک، 24: ۸۳۶ـ844.
Alizadeh, A. and Khalili, N. (2009). Estimation of Angstrom Coefficient and Developing a Regression Equation for Solar Radiation Estimation (Case study: Mashhad), Journal of Water and Soil, 23(1): 229-238. (In Persian).
Allen, R.G.; Trezza R. and Tasumi, M. (2006). Analytical Integrated Functions for Daily Solar Radiation on Slopes, Agricultural and Forest Meteorology, 139(1-2): 55-73.
Babaei Hesar, S. (2012). Evaluation of Hybrid Model to Estimate Solar Radiation in Different Climatic Conditions in Iran, MS thesis, Faculty of Natural Resources, Urmia University. 94pp. (In Persian).
Bisht, G.; Venturini, V.; Islam S. and Jiang, L.E. (2005). Estimation of the Net Radiation Using MODIS (Moderate Resolution Imaging Spectroradiometer) Data for Clear Sky Days, Remote Sensing of Environment,  97(1): 52-67.
Bisht, G. and Bras, R.L. (2010). Estimation of Net Radiation from the MODIS Data under all Sky Conditions: Southern Great Plains Case Study, Remote Sensing of Environment, 114(7): 1522-1534.
Erfanian, M. and Babaei Hessar, S. (2013). Evaluation of Hybrid Model for Estimating Daily Solar Radiation in Some Solar Sites of Iran, Journal of Water and Soil,  27(1): 158-168. (In Persian).
Heidari, V. (2015). Developing a Simple Evapotranspiration Model Using Remote Sensing and its Evaluation in Urmia Lake Basin, Master thesis, Faculty of Natural Resources, Urmia University.118 pp. (In Persian).
Hwang, K.; Choi, M.; Lee, S.O. and Seo, J.W. (2013). Estimation of Instantaneous and Daily Net Radiation from MODIS Data under Clear Sky Conditions: a Case Study in East Asia, Irrigation Science,  31(5): 1173-1184.
Jacobs, J.M.; Myers, D.A.; Anderson, M.C. and Diak, G.R. (2002). GOES Surface Insolation to Estimate Wetlands Evapotranspiration, Journal of Hydrology, 266(1): 53-65.
Jiangtao, H.; Gensuo, J.; Tianbao, Z.; Hesong, W. and Bohui, T. (2013). Satellite-based Estimation of Daily average net Radiation under Clear–sky Condition, Advances in Atmospheric Sciences,  31(3): 705-720.
Liu, B.Y.H. and Jordan, R.C. (1960). The Interrelationship and Characteristic Distribution of Direct, Diffuse and Total Solar Radiation, Solar Energy,  4(3): 1-19.
Long, D.; Gao, Y. and Singh, V.P. (2010). Estimation of Daily Average Net Radiation from MODIS Data and DEM over the Baiyangdian Watershed in North China for Clear Sky Days, Journal of hydrology,  388(3): 217-233.
Mousavi Baygi, M.; Ashraf, B. and Miyanabady, A. (2010). The Investigation of Different Models of Estimating Solar Radiation to Recommend the Suitable Model in a Semi-arid Climate, Journal of Water and Soil,  24(4): 836-844. (In Persian).
Penman, H.L. (1948). Natural Evaporation from Open Water, Bare Soil and Grass. In Proceedings of the Royal Society of London, a Mathematical, Physical and Engineering Sciences,  193(1032): 120-145.
Rogers Roddy, R. and Yau, M.K. (1989). A Short course in cloud physics, International series in natural philosophy.
Saberi, P.; Rahimi Khoob, A.; Saberi, F. and Zebardast, S. (2009). Estimation of Incoming Surface Solar Radiation by NOAA AVHRR Images (Case Study: Kermanshah), The 3th National Conference on management of irrigation and drainage networks, Jan. 27-28 Jan. 2009, Ahwaz Chamran University, Ahwaz. (In Persian).
Sabziparvar, A. (2008). A Simple Formula for Estimating Global Solar Radiation in Central Arid Deserts of Iran, Renewable Energy,  33(5): 1002-1010.
Sabziparvar, A.A. and Shadmani, M. (2011). Trends Analysis of Reference Evapotranspiration Rates by Using the Mann-Kendall and Spearman Tests in Arid Regions of Iran, Journal of Water and Soil,  25(94): 823-834. (In Persian).
Sabziparvar, A. and Shetaee, H. (2007). Estimation of global solar radiation in arid and semi-arid climates of East and West Iran, Energy, 32: 649-655.
Samani, Z.; Bawazir, A.S.; Bleiweiss, M.; Skaggs, R. and Tran, V.D. (2007). Estimating Daily Net Radiation over Vegetation Canopy through Remote Sensing and Climatic Data, Journal of irrigation and drainage engineering, 133(4): 291-297.
Tovar, H.F. and Baldasano, J.M. (2001). Solar Radiation Mapping from NOAA AVHRR Data in Catalonia, Spain, Journal of Applied Meteorology,  40(11):  1821-1834.
Yang, K.; Huang, G.W. and Tamai, N. (2001). A Hybrid Model for Estimating Global Solar Radiation, Solar energy,  70(1): 13-22.
Volume 50, Issue 4
January 2019
Pages 669-684
  • Receive Date: 16 April 2017
  • Revise Date: 28 August 2018
  • Accept Date: 28 August 2018
  • First Publish Date: 22 December 2018