ارزیابی عملکرد داده‎های بازتحلیل ERA5 در تخمین بارش ایران و واکاوی فضایی رژیم بارشی کشور

نوع مقاله : مقاله پژوهشی

نویسندگان

گروه جغرافیایی طبیعی، دانشکده جغرافیا، دانشگاه تهران، تهران، ایران

10.48308/esrj.2024.104225

چکیده

مقدمه
بارش از مهم­ترین عناصر اقلیمی محسوب می‎شود که در تعیین نقش و پراکندگی دیگر متغیرهای اقلیمی می‎تواند مؤثر باشد. این متغیر ناپایسته‎ترین متغیر اقلیمی در مقیاس زمانی و مکانی است. انجمن هواشناسی آمریکا خصایص توزیع فصلی بارش در یک مکان خاص را رژیم بارش تعریف می‎کند. هدف این مطالعه ارزیابی داده‏های بارش ماهانه پایگاه داده  ERA5نسبت به بارش اندازه‎گیری شده در ایستگاه‏های همدید کشور است. سپس توزیع فضایی رژیم بارش و آماره‌های ضریب تغییرات و چولگی آن به منظور شناسایی رفتار بارش ایران در مقیاس زمانی سالانه، فصلی و نیز ماهانه مورد واکاوی قرار می‎گیرد.  
مواد و روش­ها
در پژوهش حاضر از داده‎ بارش شبکه‌ای پایگاه داده ERA5 با قدرت تفکیک 25/0×25/0 در سال­های 2021-1979 برای پهنه ایران استفاده شده است. برای ارزیابی دقت داده‎های بازتحلیل بارش ماهانه ERA5 نسبت به داده‎های بارش اندازه‎گیری شده در ایستگاه‎های همدید کشور، 4 آماره شاخص ضریب همبستگی (Correlation Coefficient)، ریشه دوم میانگین مربعات خطای نرمال شده (NRMSE)، شاخص توافق ویلموت و شاخص اریبی استاندارد شده (Standard BIAS) به کارگرفته شد.
نتایج و بحث
ضریب همبستگی نشان داد که استفاده از بارش برآوردی این پایگاه در ماه‎های بارشی قابلیت اعتماد بالایی دارد. شاخص ریشه دوم میانگین مربعات خطای نرمال شده (NRMSE) نیز کمترین میزان(توافق عالی بین داده‎ها) را داشته است. همچنین شاخص توافق ویلموت در ماه‎های اکتبر تا آوریل کارایی بالای این پایگاه را در برآورد بارش ماهانه اغلب ایستگاه‎های همدید مورد بررسی نشان می‎دهد. بررسی شاخص اریبی استاندارد نشان داد بیشترین کم برآوردی این پایگاه، به ترتیب در ماه‎های آگوست تا اکتبر و جولای بوده است. بارش با آغاز دوره سرد از در ایران از ماه سپتامبر شروع و می به طول می‎انجامد. سری زمانی بارش ماهانه بیان‌گر رفتار نامنظم بارش کشور در هر ماه می‎باشد. عمده مناطق کشور بیشترین درصد بارشی خود را در فصل زمستان و فصل بهار دریافت می‎کنند. پربارش‌ترین و کم‌بارش‌ترین فصل‌ ایران به ترتیب زمستان و تابستان هستند. همچنین بررسی سری‎زمانی 42 ساله بارش ایران نوسانات دریافت بارش در پهنه کشور در سال‎های مختلف را روشن نمود.
نتیجه­ گیری
مقایسه سری‎زمانی بارش ماهانه در پایگاه داده بازتحلیل ERA5 نسبت به بارش اندازه‎گیری شده ایستگاه‎های همدید، نشان از الگوی مشابه این نوع داده در طولانی مدت داشت. بارش با آغاز دوره سرد از سپتامبر در کشور شروع می­شود و تا می به طول می‎انجامد، که اوج میانگین بارش در مناطق سواحل دریای خزر و سپس در نواحی رشته‌کوه‌های زاگرس دریافت می‌شود. سهم بارش زمستانه کشور 5/44 درصد کل بارش سال است، به عبارتی رژیم اصلی بارش عمدتاً زمستانه است. نتایج تا حدودی بیانگیر تغییر تدریجی رژیم بارش کشور می‎باشد، چرا که از سهم بارش بهاره (2/8 میلی‎متر کاهش در 42 سال) و زمستانه (26/28 میلی‎متر کاهش در 42 سال) کشور کاسته شده و به سهم بارش پاییزه کشور اضافه گردیده است.

کلیدواژه‌ها

موضوعات

عنوان مقاله [English]

Evaluation the performance of ERA5 reanalysis data in Iran's rainfall estimation and spatial analysis of the country's precipitation regime

نویسندگان [English]

  • Susan Heidari
  • Mostafa Karimi
  • Azar Beyranvand
Department of Physical Geography, Faculty of Geography, University Tehran Tehran, Iran
چکیده [English]

Introduction
Precipitation is one of the most important climatic elements that can be effective in determining the role and distribution of other climatic variables. This variable is the most unstable climatic variable in the temporal and spatial scale. The American Meteorological Society defines the characteristics of the seasonal distribution of precipitation in a particular place as a precipitation regime. The aim of this study is to evaluate the monthly rainfall data of ERA5 database compared to the rainfall measured in the synoptic stations of the country. Then, the spatial distribution of the rainfall regime and its coefficient of variation and skewness are analyzed in order to identify Iran's rainfall behavior in annual, seasonal and monthly time scales.
 
Materials and Methods
In the present study, the reanalyzed gridded precipitation data (ERA5) with a resolution of 0.25 x 0.25 was used from the years 1979 to 2021. According to the findings of Hassler and Lauer (2011), ERA5 data has made a clear improvement compared to ERA-Interim data and has shown small biases compared to other reanalysis data. To evaluate the monthly data of this database compared to the monthly rainfall data in synoptic stations of the country, the correlation coefficient, Normalized Root Mean Square Error (NRMSE), the Wilmot agreement index and the standardized Bias index were used.
 
Results and Discussion
The correlation coefficient showed that using the estimated precipitation of this database in rainy months has high reliability. Indicators NRMSE and Wilmot's agreement show the high efficiency of this database. Standard BIAS showed that the most underestimation of this database was in the months of August to October and July, respectively.
Rainfall begins in September and lasts until May in Iran. The monthly rainfall time series shows the irregular behavior of rainfall in each month. Most regions of the country receive their highest percentage of precipitation in winter and spring. 
The rainiest and least rainy seasons of Iran are winter and summer, respectively. Also, the 42-year time series analysis of Iran's rainfall clarified the fluctuations of rainfall in the country in different years.
The coefficient of monthly changes in precipitation is indicative of the intensity of month-to-month changes in precipitation. This index can provide a relative pattern of rainfall variability. In fact, the map of the coefficient of monthly changes in precipitation is reminiscent of extreme fluctuations in monthly precipitation; So that the range of monthly rainfall changes is less than 20% from December to March in the northwest, north and west of the country and reaches more than 450% in July to September in the south and southeast.
Most regions of the country receive their highest percentage of precipitation in winter and spring. The rainiest and least rainy seasons of Iran are winter and summer, respectively. The most important advantage of winter rainfall is that it is scattered in all regions of the country. But summer rain can be seen only in the northern parts and sometimes parts of the east and southeast of the country.
In the autumn season, there is an increase of about 17.5 mm of precipitation in the studied period. But in other seasons, there is a decreasing trend, and the maximum of this negative trend is related to the winter season, which shows a decrease of 28 mm in rainfall. The above changes are statistically significant at the 99% confidence level. ،hese changes show the shift of Iran's seasonal rainfall regime from winter and spring to autumn over time.
Conclusion
A similar rainfall pattern was seen between the two types of data in Iran. Rainfall begins from September and lasts until May. Peak of the average rainfall is received in the coastal areas of the Caspian Sea and then in the areas of the Zagros mountain. The share of winter precipitation in the country is 44.5% of the total precipitation of the year, in other words, the main regime of precipitation is mainly winter. The results to some extent indicate the gradual change of the country's rainfall regime. Because the precipitation of spring (8.2 mm decrease in 42 years) and winter (28.26 mm decrease in 42 years) in Iran has been reduced but autumn rainfall in Iran has been added.
 

کلیدواژه‌ها [English]

  • Data validation of ERA5
  • Comparative data analysis
  • Spatial Variability of Precipitation
  • Precipitation Trends

مراجع

References
 
Ahmadi, M., Fathniya, A. and Abkharabat, S., 2015. Trend analysis of Iran's precipitation and its relation to the teleconnection forces, Journal of Climate Research, v. 1394(23), p.19-32 (in Persian).
Alijani, B., O’Brien, J. and Yarnal, B., 2008. Spatial analysis of precipitation intensity and concentration in Iran, Theor Appl Climatol, v. 94, p. 107-124.
Alijani, B., Mofidi, A., Jafarpour, Z. and Aliakbari-Bidokhti, A., 2012. Atmospheric circulation patterns of the summertime rainfalls of southeastern Iran during July 1994, Earth and Space physics, v. 37(3), p. 205-227 (in Persian).
Alijanian, M., Rakhshandehroo, G.R., Mishra, A.K. and Dehghani, M., 2017. Evaluation of satellite rainfall climatology using CMORPH, PERSIANN‐CDR, PERSIANN, TRMM, MSWEP over Iran, International Journal of Climatology, v. 37(14), p. 4896-4914.
Ansari Basir, A., 2007. evaluation of seasonal rainfall regime in Iran using the harmony method, master's thesis, Supervisors: Seyfaleh Amin and Mohammad Reza Pishwaie, Faculty of Agriculture, Shiraz University (in Persian).
Arabi, Z., 2006. Synoptic analysis of rainfall from 12 to 17 July 1999 in Iran, Geographical Researches, v. 56, p. 1-15 (in Persian).
Asakereh, H. and Razmi, R., 2014. Temporal Distribution and Regime of Precipitation of Northwest of Iran. Geographical Research, v. 29(1) p. 25-41 (in Persian).
Asakereh, H. and Ghandali, N.V., 2021. Changes of precipitation regime of the Iranian Coast of Caspian Sea (ICCS), Geography and Development, v. 19(64), p. 115-142 (in Persian).
Asakereh, H. and Razmi, R., 2011. Change of Precipitation regime in northwest Iran, Climatology Research, v. 8-7, p. 114-99 (in Persian).
Asakereh, H., 2007. Spatio–temporal changes of Iran inland precipitation during recent decades, Geography and Development, v. 5(10), p. 145-164 (in Persian).
Asakereh, H., 2011. Fundamentals of Statistical Climatology, Zanjan University Publications (in Persian).
Asakereh, H., Nasrabadi, E. and Masoodian, S.A., 2014. Recognition and regionalization of daily precipitation frequency distribution in Iran. Geographical Researches, v. 29(3), p. 1-16 (in Persian).
Azizi Mobaser, J., Rasoulzadeh, A., Rahmati, A., Shayeghi, A. and Bakhtar, A., 2021. Evaluating the Performance of Era-5 Re-Analysis Data in Estimating Daily and Monthly Precipitation, Case Study; Ardabil Province. Iranian Journal of Soil and Water Research, v. 51(11), p. 2937-2951 (in Persian).
Babaei Fini, A.A. and Farajzadeh, M., 2003. Spatial indexes of precipitation and its changes in Iran, the third regional conference and the first national conference on climate change, Isfahan, 29 October to 1 November (in Persian).
Barati, G., Alijani, B. and Moradi, M., 2024. Zoning and analysis of pervasive rainfall in rainy areas of Iran in the statistical period of 30 years (1987-1987). Journal of Applied researches in Geographical Sciences, v. 23(71), p. 103-121 (in Persian).
Barlow, M., Zaitchik, B., Paz, S., Black, E., Evans, J. and Hoell, A., 2016. A Review of Drought in the Middle East and Southwest Asia. Journal of Climate, v. 29, p. 8547-8574, doi:10.1175/JCLI-D-13-00692.1.
Bodghjamali, J., Javanmard, S. and Tajbakhsh, S., 2020. The estimation of type and amount rainfall using TMI Sensor of TRMM Satellite, Journal of Climate Research, v. 1398(37), p. 38-56 (in Persian).
Collins, B., Ramezani Etedali, H., Tavakol, A. and Kaviani, A., 2021. Spatiotemporal variations of evapotranspiration and reference crop water requirement over 1957–2016 in Iran based on CRU TS gridded dataset, Journal of Arid Land, v. 13, p. 858-878.
Darand, M. and Zande Karimi, S., 2015. Evaluation of Spatio-Temporal Accuracy of Precipitation of European Center for Medium-Range Weather Forecasts (ECMWF) over Iran. Physical Geography Research Quarterly, v. 47(4), p. 651-675 (in Persian).
Darand, M. & Khandu, K., 2020. Statistical evaluation of gridded precipitation datasets using rain gauge observations over Iran, Journal of Arid Environments, v. 178, Doi: 10.1016/j.jaridenv.2020.104172.
Darand, M. and Pazhoh, F., 2022. Spatiotemporal changes in precipitation concentration over Iran during 1962–2019. Climatic Change, v. 173(3-4), Doi: 10.1007/s00704-020-03192-6.
Dee, D.P., Uppala, S.M., Simmons, A.J., Berrisford, P., Poli, P., Kobayashi, S., Andrae, U., Balmaseda, M.A., Balsamo, G., Bauer, P. et al, 2011. The ERA-Interim reanalysis: Configuration and performance of the data assimilation system. Q. J. R. Meteorol. Soc., v. 137, p. 553-597.
Doustkamian, M., Asakereh, H. and Darand, M., 2021. Investigation and analysis of turbulence and fluctuations of rainfall regions of Iran. jgs 2021; 21 (60), p. 127-149 (in Persian).
Erfani, A., Babaeian, I. and Entezari, A., 2020. ERA-Interim. Journal of Climate Research, v. 1398(38), p. 77-92 (in Persian).
Fallah Ghalhari, G.A., Dadashi Roudbari, A.A. and Asadi, M., 2016. Identifying the spatial and temporal distribution characteristics of precipitation in Iran, Arab J Geosci, v. 9, p. 1-12. https://doi.org/10.1007/s12517-016-2606-4.
Fallah, A., Rakhshandehroo, G.R., Berg, P.O.S. and Orth, R., 2020. Evaluation of precipitation datasets against local observations in southwestern Iran. International Journal of Climatology, v. 40(9), p. 4102-4116.
Ghebreyesus, D. and Sharif, H.O., 2021. Time Series Analysis of Monthly and Annual Precipitation in The State of Texas Using High-Resolution Radar Products. Water, v. 13(7), https://doi.org/10.3390/w13070982.
Gorjizade, A., AkhondAli, A., Shahbazi, A. and Moridi, A., 2019. Comparison and evaluation of precipitation estimated by era-interim, persiann-cdr and chirps models at the upstream of maroon dam. Iran-Water Resources Research, v. 15(1), p. 267-279 (in Persian).
HadiPour, S., Abd Wahab, A.K. and Shahid, S., 2020. Spatiotemporal changes in aridity and the shift of drylands in Iran. Atmospheric Research, v. 233, https://doi.org/10.1016/j.atmosres.2019.104704.
Halabian, A.H., 2017. Assesment of spatial-temporal changes of precipitation in Iran, Desert Ecosystem Engineering Journal, v. 5(13), p. 101-116 (in Persian).
Hassler, B. and Lauer, A., 2021. Comparison of reanalysis and observational precipitation datasets including ERA5 and WFDE5. Atmosphere, v. 12(11), https://doi.org/10.3390/atmos12111462.
Hersbach, H. and Dee, D., 2016. ERA5 reanalysis is in production, ECMWF Newsletter, 147. Reading, UK: ECMWF.
Izadi, N., Karakani, E.G., Saadatabadi, A.R., Shamsipour, A., Fattahi, E. and Habibi, M., 2021. Evaluation of ERA5 precipitation accuracy based on various time scales over Iran during 2000–2018. Water, v. 13(18), https://doi.org/10.3390/w13182538.
-Jiang, Q.C., 2021. Evaluation of the ERA5 reanalysis precipitation dataset over Chinese Mainland. J. Hydrol, v. 595, https://doi.org/10.1016/j.jhydrol.2020.125660.
-Jiang, Q., Li, W., Fan, Z., He, X., Sun, W., Chen, S., Wen, J., Gao, J. and Wang, J., 2021. Evaluation of the ERA5 reanalysis precipitation dataset over Chinese Mainland, Journal of Hydrology, v. 595, https://doi.org/10.1016/j.jhydrol.2020.125660.
Karampoor, M., ZareiCheghabaleki, Z., Halimi, M. and Nouroozi Mirza, M., 2018. Study of Iran’s monthly and annual Rainfall variations in different classes. Scientific-Research Quarterly of Geographical Data (SEPEHR), v. 27(105), p. 199-217 (in Persian).
Karimi, M., Heidari, S. and Rafati, S., 2021. The trend of atmospheric water cycle components (precipitation and precipitable water) in catchments of Iran, Journal of Spatial Analysis Environmental Hazarts, v. 8(2), p. 33-54 (in Persian).
Karimi, M. and Heidari, S., 2023. Variability and trend of changes in the severity-area of drought and wet in Iran, Journal of Natural Environmental Hazards, v. 12(36), p. 129-150 (in Persian).
Kaviani, M.R., 1988. statistical analysis of Iran's rainfall regime, Roshd of geography education, v. 13, p. 4-12 (in Persian).
Khalili, K., Tahoudi, M.N., Mirabbasi, R. and Ahmadi, F., 2016. Investigation of spatial and temporal variability of precipitation in Iran over the last half century, Stochastic environmental research and risk assessment, v. 30, p. 1205-1221.
Khorshiddoust, A.M. and Jafarzadeh, F., 2020. Forecasting and analyzing of rainfall changes in the southern coasts of Caspian Sea in order to environmental planning using SDSM model, Journal of geographical-space, v. 20(70), p. 37-59 (in Persian).
Kumar, V., Jain, S.K. and Singh, Y., 2010. Analysis of long-term rainfall trends in India, Hydrological Sci. J., v. 55, p. 484-496.
Mahmoudvand, R., Hassani, H. and Wilson, R., 2007. Is the sample coefficient of variation a good estimator for the population coefficient of variation?" world Applied Sciences Journal, v. 2(5), p. 519-522.
Masoudiyan, S.A., 2003. Investigation of precipitation geographical dispersion in Iran through rotated factor analysis, Geography and Development, v. 1(1), p. 79-87 (in Persian).
Masoudian, S.A. and Kaviani, M.R., 2007. Climatology of Iran, University of Isfahan, Isfahan.
Masoudian, S.A. and Atai, H., 2005. Identification of Iran's rainy seasons by cluster analysis, Isfahan University Research Journal, v. 18(1), p. 1-12 (in Persian).
Merianji, Z., 2012. Variability of the rainfall regime in Iran, PhD thesis, Supervisors: Saeid Movahedi, Hossein Asakereh, and Ali Akbar Sabziparvar, Faculty of Geography, University of Isfahan (in Persian).
Mirian, M., Karampoor, M., Moradi, M., Ghemi, H. and Nasiri, B., 2023. Statistical and anomalies analysis of the 50-year precipitation of the synoptic stations in Iran (in Persian).
Moghabel, M., Davoodi, M., Nistani, A. and Taghavi, F., 2011. Identifying the Changes in Precipitation Regime over Iran during Recent Decades. Nivar, v. 35(73-72), p. 55-66 (in Persian).
Najafi, M.S. and Akbari Moghadam Sani, S., 2022. Evaluation the performance of three gridded datasets in estimating the time series of extreme precipitation in Iran. Climate Change Research, v. 3(11), p. 79-98 (in Persian).
Nazaripour, H., 2011. Synoptic analysis of Iran's rainfall continuity, PhD thesis, Supervisors: Mahmoud Khosravi and Abolfazl Masoudian, Faculty of Geography and Environmental Planning, University of Sistan and Baluchistan (in Persian).
Rakhmatova, N., Arushanov, M., Shardakova, L., Nishonov, B., Taryannikova, R., Rakhmatova, V. and Belikov, D.A., 2021. Evaluation of the perspective of ERA-Interim and ERA5 reanalyses for calculation of drought indicators for Uzbekistan, Atmosphere, v. 12(5), https://doi.org/10.3390/atmos12050527.
Raziei, T. and Azizi, G.H.A.S.E.M., 2009. Delineation of homogeneous precipitation regions in Western Iran, Journal of Geography and Environmental Planning, v. 20(2), p. 65-86 (in Persian).
Raziei, T. and Azizi, GH., 2007. Spatial changes in rainfall frequency distribution patterns in Iran, Physical Geography Research, v. 65, p. 93-108 (in Persian).
Raziei, T. and Sotoudeh, F., 2017. Investigation of the accuracy of the European Center for Medium Range Weather Forecasts (ECMWF) in forecasting observed precipitation in different climates of Iran. Journal of the earth and space physics, v. 43(1), p. 133-147 (in Persian).
Razmi, R., 2010. Changing the rainfall regime of Azarbaijan in Iran, Master's thesis, Supervisors: Hossein Asakereh, Faculty of Humanities, Zanjan University (in Persian).
Rezaei, M., Azhdary Moghaddam, M.E.H.D.I., Azizyan, G. and Shamsipur, A.A., 2023. Assessment of precipitation obtained from gridded data bases in southern Baluchestan basin. Environment and Water Engineering, v. 9(1) (in Persian).
Sabziparvar, A.A., Movahedi, S., Asakereh, H., Maryanaji, Z. and Masoodian, S.A., 2015. Geographical factors affecting variability of precipitation regime in Iran, Theoretical and Applied Climatology, v. 120, p. 367-376.
Taghizadeh, E., Ahmadi-Givi, F., Brocca, L. and Sharifi, E., 2021. Evaluation of satellite/reanalysis precipitation products over Iran, International Journal of remote sensing, v. 42(9), p. 3474-3497.
Taherianzad, A., 2017. Investigating and analyzing the nature and structure of atmospheric changes in Iran's spring rains, master's thesis, Supervisors: Masoud Jalali, Faculty of Humanities, Zanjan University (in Persian).
Trenberth, K.E., 2011. Changes in precipitation with climate change. Clim. Res., v. 47, p. 123-138.
Wang, G., Zhang, X. and Zhang, S., 2019. Performance of three reanalysis precipitation datasets over the qinling-daba Mountains, eastern fringe of Tibetan plateau, China. Advances in Meteorology.
Zhao, X., Xia, H., Pan, L., Song, H., Niu, W., Wang, R. et al, 2021. Drought monitoring over Yellow River basin from 2003–2019 using reconstructed MODIS land surface temperature in Google Earth Engine. Remote Sens., v. 13, https://doi.org/10.3390/rs13183748
 
 

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