Document Type : Research Paper
Authors
1 Department of Engineering Hydrology, Institute of Hydrology and Oceanology, Russian State Hydrometeorological University, Saint Petersburg, Russia.
2 2Kurdistan Agricultural and Natural Resources Research and Education Center, Agricultural Research, Education and Extension Organization (AREEO), Sanandaj, Iran.
Abstract
This study explores agricultural drought variability by applying both classical and rank-based statistical methods within two distinct probabilistic frameworks, aiming to assess how distribution choice affects the interpretation of drought patterns. Monthly meteorological data from 1998 to 2022 were processed into four drought indices: SPI, aSPI, RDI, and eRDI. Effective precipitation was calculated using the USDA method and CROPWAT, and potential evapotranspiration (ET0) was determined with the FAO Penman-Monteith approach. Each index was standardized with both gamma and log-normal distributions in DrinC to evaluate the influence of distribution choice on trend detection. Trend analysis was conducted using linear regression with Pearson correlation for parametric tests and the Mann–Kendall test with Sen’s slope for non-parametric tests. Results from both methods and distributions were consistent: median Sen slopes were within ±0.03 index units per year, and Mann–Kendall Z scores ranged from −0.82 to 0.63, indicating no significant monotonic change. Regression slopes supported this, remaining below 0.03 with p-values above 0.25. The close agreement between parametric and non-parametric results, and between gamma and log-normal distributions, shows that model selection does not bias drought trend analysis. This multi-index, dual-distribution framework provides a robust and transferable methodology for drought monitoring, particularly in data-scarce and semi-arid regions worldwide.
Keywords
Ahmadpari, H. and Khaustov, V. (2025a) ‘Analyzing meteorological and hydrological droughts in the Darreh Dozdan River Basin through drought indices’, Environment and Water Engineering, 11(2), pp. 174–184. doi: https://doi.org/10.22034/ewe.2025.506959.2004
Ahmadpari, H. and Khaustov, V. (2025b) 'Agricultural drought monitoring using meteorological indices in Darreh Dozdan Basin, Iran'. Advances in Civil Engineering and Environmental Science, 2(2), pp. 72-84. doi: https://doi.org/10.22034/acees.2025.512324.1022
Ahmadpari, H., Khaustov, V., and Amini, A. (2025) 'Combined parametric and non-parametric assessment of relative humidity trends in a semi-arid river basin'. Environment and Water Engineering, 11(4), pp. 519-532. doi: https://doi.org/10.22034/ewe.2025.538388.2048
Ahmadpari, H., Safavi Gerdini, M., and Ebrahimi, M. (2019) 'An appropriate method for estimating potential evapotranspiration in the absence of meteorological data (The case study of Khorrambid Township in Fars Province)'. Land Management Journal, 7(2), pp. 223-230. doi: https://doi.org/10.22092/lmj.2019.120559
Ahmadpari, H., Hashemi Garmdareh, S. E. and Ghalehkohneh, K. (2017) 'Comparison of different methods of estimating potential evapotranspiration by FAO Penman Monteith (Case Study: Sepidan Region)'. Nivar, 41(98-99), pp. 13-22. doi: https://doi.org/10.30467/nivar.2017.51886
Akobeng, A. K. (2016) 'Understanding type I and type II errors, statistical power and sample size'. Acta Paediatrica, 105(6), pp. 605-609. doi: https://doi.org/10.1111/apa.13384
Almendra-Martín, L. et al. (2021) 'Agricultural drought trends on the Iberian Peninsula: An analysis using modeled and reanalysis soil moisture products'. Atmosphere, 12(2), p. 236. doi: https://doi.org/10.3390/atmos12020236
Amini, A. (2020) 'The role of climate parameters variation in the intensification of dust phenomenon'. Natural Hazards, 102(1), pp. 445-468. doi: https://doi.org/10.1007/s11069-020-03933-w
Amini, A. et al. (2009) 'Adjustment of peak streamflows of a tropical river for urbanization'. American Journal of Environmental Sciences, 5(3), pp. 285-294. doi: https://doi.org/10.3844/ajessp.2009.285.294
Amini, A. et al. (2019) 'Application of TRMM precipitation data to evaluate drought and its effects on water resources instability'. Applied Sciences, 9(24), p. 5377. doi: https://doi.org/10.3390/app9245377
Amiri, M. J. et al. (2015) 'Detection of climate changes by mann-kendall analysis and drought indexes (Case study: Agh Gol wetland)'. Journal of Environmental Studies, 41(3), pp. 545-561. doi: https://doi.org/10.22059/jes.2015.55896 Asadi Zarch, M. A., and Motraghi, F. (2025) 'Global evaluation of optimal probability distribution functions for RDI assessments'. Hydrological Processes, 39(1), p. e70037. doi: https://doi.org/10.1002/hyp.70037
Bararkhanpour, S. et al. (2020) 'Study of seasonal and annual rainfall changes with quantile regression method (case study: Gorgan Hashem-Abad Station'. Journal of Climate Research, 1398(39), pp. 89-104. Available at: https://clima.irimo.ir/article_113692.html?lang=en (Accessed: 22 August 2025)
Basati, S., Yarahmadi, D., and Nasiri, B. (2014) 'Study of changes in the precipitation forms and clarify the relative humidity and temperature effects on them (Kermanshah station)'. Nivar, 38(87-86), pp. 63-72. Available at: https://nivar.irimo.ir/article_13257.html?lang=en (Accessed: 23 September 2025).
Bharambe, K. P. et al. (2023) 'Impacts of climate change on drought and its consequences on the agricultural crop under worst-case scenario over the Godavari River Basin, India'. Climate Services, 32, p. 100415. doi: https://doi.org/10.1016/j.cliser.2023.100415
Binesh, S. et al. (2020) 'Preparation of spatial distribution maps of saffron water requirement in Kermanshah province'. International Journal of Engineering and Technology, 12(2), pp. 321-336. doi: https://dx.doi.org/10.21817/ijet/2020/v12i2/201202118
Bonovas, S., and Piovani, D. (2023) 'On p-values and statistical significance'. Journal of Clinical Medicine, 12(3), pp. 1-4. doi: https://doi.org/10.3390/jcm12030900
Chen, S., Ghadami, A., and Epureanu, B. I. (2022) 'Practical guide to using Kendall’s τ in the context of forecasting critical transitions'. Royal Society Open Science, 9(7), pp. 1-10. doi: https://doi.org/10.1098/rsos.211346
Chen, Y. et al. (2016) 'Investigating trends in streamflow and precipitation in Huangfuchuan Basin with wavelet analysis and the Mann-Kendall test'. Water, 8(3), pp. 1-32. doi: https://doi.org/10.3390/w8030077
Eshghizadeh, M. and Esmaeilian, Y. (2023) 'Identifying agricultural drought trends using RDI and eRDI indices in a hot and dry climate'. Geography and Human Relationships, 5(4), pp. 625-652. doi: https://doi.org/10.22034/gahr.2022.364978.1756
Fathi, S. et al. (2025) 'A Multi-Criteria Framework for Water Resource Management: Combining WEAP and TOPSIS for Optimal Solutions'. Advances in Civil Engineering and Environmental Science, 2(1), pp. 10-22. doi: https://doi.org/10.22034/acees.2025.484672.1011
Garba, H., and Udokpoh, U. U. (2023) 'Analysis of trend in meteorological and hydrological time-series using Mann-Kendall and Sen’s slope estimator statistical test in Akwa Ibom state, Nigeria'. International Journal of Environment and Climate Change, 13(10), pp. 1017-1035. doi: https://doi.org/10.9734/ijecc/2023/v13i102748
Gharibreza, M. et al. (2018) 'Evolutionary trend of the Gorgan Bay (southeastern Caspian Sea) during and post the last Caspian Sea level rise'. Catena, 166, pp. 339-348. doi: https://doi.org/10.1016/j.catena.2018.04.016
Ghorbani, H., Vali, A., and Zarepour, H. (2019) 'Analysis of the Climatological Drought Trend Variations Using Mann-Kendall, Sen and Pettitt Tests in Isfahan Province'. Journal of Spatial Analysis Environmental Hazards, 6 (2), pp. 129-146. doi: http://dx.doi.org/10.29252/jsaeh.6.2.129
Gocic, M., and Trajkovic, S. (2013) 'Analysis of changes in meteorological variables using Mann-Kendall and Sen's slope estimator statistical tests in Serbia'. Global and planetary change, 100, pp. 172-182. doi: https://doi.org/10.1016/j.gloplacha.2012.10.014
Hu, J. et al. (2022) 'Some aspects of response variable selection and estimation in multivariate linear regression'. Journal of Multivariate Analysis, 188, pp. 1-15. doi: https://doi.org/10.1016/j.jmva.2021.104821
Ibrahim, H. M., Alghamdi, A. G., and Aly, A. A. (2024) 'Assessing drought patterns in al-baha: implications for water resources and climate adaptation'. Sustainability, 16(22), pp. 1-26. doi: https://doi.org/10.3390/su16229882
Ahmadpari, H. and Khaustov, V. (2025b) 'Agricultural drought monitoring using meteorological indices in Darreh Dozdan Basin, Iran'. Advances in Civil Engineering and Environmental Science, 2(2), pp. 72-84. doi: https://doi.org/10.22034/acees.2025.512324.1022
Ahmadpari, H., Khaustov, V., and Amini, A. (2025) 'Combined parametric and non-parametric assessment of relative humidity trends in a semi-arid river basin'. Environment and Water Engineering, 11(4), pp. 519-532. doi: https://doi.org/10.22034/ewe.2025.538388.2048
Ahmadpari, H., Safavi Gerdini, M., and Ebrahimi, M. (2019) 'An appropriate method for estimating potential evapotranspiration in the absence of meteorological data (The case study of Khorrambid Township in Fars Province)'. Land Management Journal, 7(2), pp. 223-230. doi: https://doi.org/10.22092/lmj.2019.120559
Ahmadpari, H., Hashemi Garmdareh, S. E. and Ghalehkohneh, K. (2017) 'Comparison of different methods of estimating potential evapotranspiration by FAO Penman Monteith (Case Study: Sepidan Region)'. Nivar, 41(98-99), pp. 13-22. doi: https://doi.org/10.30467/nivar.2017.51886
Akobeng, A. K. (2016) 'Understanding type I and type II errors, statistical power and sample size'. Acta Paediatrica, 105(6), pp. 605-609. doi: https://doi.org/10.1111/apa.13384
Almendra-Martín, L. et al. (2021) 'Agricultural drought trends on the Iberian Peninsula: An analysis using modeled and reanalysis soil moisture products'. Atmosphere, 12(2), p. 236. doi: https://doi.org/10.3390/atmos12020236
Amini, A. (2020) 'The role of climate parameters variation in the intensification of dust phenomenon'. Natural Hazards, 102(1), pp. 445-468. doi: https://doi.org/10.1007/s11069-020-03933-w
Amini, A. et al. (2009) 'Adjustment of peak streamflows of a tropical river for urbanization'. American Journal of Environmental Sciences, 5(3), pp. 285-294. doi: https://doi.org/10.3844/ajessp.2009.285.294
Amini, A. et al. (2019) 'Application of TRMM precipitation data to evaluate drought and its effects on water resources instability'. Applied Sciences, 9(24), p. 5377. doi: https://doi.org/10.3390/app9245377
Amiri, M. J. et al. (2015) 'Detection of climate changes by mann-kendall analysis and drought indexes (Case study: Agh Gol wetland)'. Journal of Environmental Studies, 41(3), pp. 545-561. doi: https://doi.org/10.22059/jes.2015.55896 Asadi Zarch, M. A., and Motraghi, F. (2025) 'Global evaluation of optimal probability distribution functions for RDI assessments'. Hydrological Processes, 39(1), p. e70037. doi: https://doi.org/10.1002/hyp.70037
Bararkhanpour, S. et al. (2020) 'Study of seasonal and annual rainfall changes with quantile regression method (case study: Gorgan Hashem-Abad Station'. Journal of Climate Research, 1398(39), pp. 89-104. Available at: https://clima.irimo.ir/article_113692.html?lang=en (Accessed: 22 August 2025)
Basati, S., Yarahmadi, D., and Nasiri, B. (2014) 'Study of changes in the precipitation forms and clarify the relative humidity and temperature effects on them (Kermanshah station)'. Nivar, 38(87-86), pp. 63-72. Available at: https://nivar.irimo.ir/article_13257.html?lang=en (Accessed: 23 September 2025).
Bharambe, K. P. et al. (2023) 'Impacts of climate change on drought and its consequences on the agricultural crop under worst-case scenario over the Godavari River Basin, India'. Climate Services, 32, p. 100415. doi: https://doi.org/10.1016/j.cliser.2023.100415
Binesh, S. et al. (2020) 'Preparation of spatial distribution maps of saffron water requirement in Kermanshah province'. International Journal of Engineering and Technology, 12(2), pp. 321-336. doi: https://dx.doi.org/10.21817/ijet/2020/v12i2/201202118
Bonovas, S., and Piovani, D. (2023) 'On p-values and statistical significance'. Journal of Clinical Medicine, 12(3), pp. 1-4. doi: https://doi.org/10.3390/jcm12030900
Chen, S., Ghadami, A., and Epureanu, B. I. (2022) 'Practical guide to using Kendall’s τ in the context of forecasting critical transitions'. Royal Society Open Science, 9(7), pp. 1-10. doi: https://doi.org/10.1098/rsos.211346
Chen, Y. et al. (2016) 'Investigating trends in streamflow and precipitation in Huangfuchuan Basin with wavelet analysis and the Mann-Kendall test'. Water, 8(3), pp. 1-32. doi: https://doi.org/10.3390/w8030077
Eshghizadeh, M. and Esmaeilian, Y. (2023) 'Identifying agricultural drought trends using RDI and eRDI indices in a hot and dry climate'. Geography and Human Relationships, 5(4), pp. 625-652. doi: https://doi.org/10.22034/gahr.2022.364978.1756
Fathi, S. et al. (2025) 'A Multi-Criteria Framework for Water Resource Management: Combining WEAP and TOPSIS for Optimal Solutions'. Advances in Civil Engineering and Environmental Science, 2(1), pp. 10-22. doi: https://doi.org/10.22034/acees.2025.484672.1011
Garba, H., and Udokpoh, U. U. (2023) 'Analysis of trend in meteorological and hydrological time-series using Mann-Kendall and Sen’s slope estimator statistical test in Akwa Ibom state, Nigeria'. International Journal of Environment and Climate Change, 13(10), pp. 1017-1035. doi: https://doi.org/10.9734/ijecc/2023/v13i102748
Gharibreza, M. et al. (2018) 'Evolutionary trend of the Gorgan Bay (southeastern Caspian Sea) during and post the last Caspian Sea level rise'. Catena, 166, pp. 339-348. doi: https://doi.org/10.1016/j.catena.2018.04.016
Ghorbani, H., Vali, A., and Zarepour, H. (2019) 'Analysis of the Climatological Drought Trend Variations Using Mann-Kendall, Sen and Pettitt Tests in Isfahan Province'. Journal of Spatial Analysis Environmental Hazards, 6 (2), pp. 129-146. doi: http://dx.doi.org/10.29252/jsaeh.6.2.129
Gocic, M., and Trajkovic, S. (2013) 'Analysis of changes in meteorological variables using Mann-Kendall and Sen's slope estimator statistical tests in Serbia'. Global and planetary change, 100, pp. 172-182. doi: https://doi.org/10.1016/j.gloplacha.2012.10.014
Hu, J. et al. (2022) 'Some aspects of response variable selection and estimation in multivariate linear regression'. Journal of Multivariate Analysis, 188, pp. 1-15. doi: https://doi.org/10.1016/j.jmva.2021.104821
Ibrahim, H. M., Alghamdi, A. G., and Aly, A. A. (2024) 'Assessing drought patterns in al-baha: implications for water resources and climate adaptation'. Sustainability, 16(22), pp. 1-26. doi: https://doi.org/10.3390/su16229882
Jiang, Y., and Sun, W. (2025) 'Day-ahead electricity price prediction and error correction method based on feature construction–singular spectrum analysis–long short-term memory'. Energies, 18(4), 1-22. doi: https://doi.org/10.3390/en18040919
Kwak, S. (2023) 'Are only p-values less than 0.05 significant? A p-value greater than 0.05 is also significant'. Journal of Lipid and Atherosclerosis, 12(2), pp. 89-95. doi: https://doi.org/10.12997/jla.2023.12.2.89
Iacuzzi, N. et al. (2025) 'Crop Water Requirement Estimated with Data-Driven Models Improves the Reliability of CROPWAT 8.0 and the Water Footprint of Processing Tomato Grown in a Hot-Arid Environment', Agronomy, 15(7), pp. 2-19. doi: https://doi.org/10.3390/agronomy15071533
Lee, C. et al. (2023) 'Optimal probability distribution and applicable minimum time-scale for daily standardized precipitation index time series in South Korea'. Atmosphere, 14(8), pp. 1-19. doi: https://doi.org/10.3390/atmos14081292
Li, L. et al. (2024) 'Evolution of drought characteristics and propagation from meteorological to agricultural drought under the influences of climate change and human activities', Environmental Science and Pollution Research, 31(18), pp. 26713-26736. doi: https://doi.org/10.1007/s11356-024-32709-z
Liu, L., and Xu, Z. X. (2016) 'Regionalization of precipitation and the spatiotemporal distribution of extreme precipitation in southwestern China', Natural Hazards, 80, pp. 1195-1211. doi: https://doi.org/10.1007/s11069-015-2018-x
Lornezhad, E., Ebrahimi, H., and Rabieifar, H. (2023) 'Analysis of precipitation trends and characteristics on agricultural water resources in Lorestan province', Journal of Water and Soil Resources Conservation, 13(1), pp. 27-40. doi: https://doi.org/10.30495/wsrcj.2023.69930.11327
Maier, M., and Lakens, D. (2022) 'Justify your alpha: A primer on two practical approaches', Advances in Methods and Practices in Psychological Science, 5(2), pp. 1-14. doi: https://doi.org/10.1177/25152459221080396
Patel, R., and Patel, A. (2024) 'Evaluating the impact of climate change on drought risk in semi-arid region using GIS technique'. Results in Engineering, 21, p. 101957. doi: https://doi.org/10.1016/j.rineng.2024.101957
Polroudimoghadam, M., Hamzeh, S. and Vazifehdoust, M. (2016) 'Investigating the trend of rainfall and runoff changes using the Global Land Data Assimilation System (GLDAS) in Doosti Dam Basin'. Scientific- Research Quarterly of Geographical Data, 25(98), pp. 43-56. doi: https://doi.org/10.22131/sepehr.2016.22137
Raeesi, M. et al. (2023) 'Estimation of vegetation changes concerning annual rainfall and temperature in Semnan Province', Journal of Environmental Erosion Research, 13 (4), pp. 56-82. doi: http://dx.doi.org/10.61186/jeer.13.4.56
Rahmani, Z. and Ahmadi, J. (2024) 'The impact of human activities on climate change', Sprin Journal of Arts, Humanities and Social Sciences, 3(6), pp. 24-27. doi: https://doi.org/10.55559/sjahss.v3i6.362
Rezaei, M. et al. (2024) 'Prediction of agricultural drought index in a hot and dry climate using advanced hybrid machine learning'. Ain Shams Engineering Journal, 15(5), p. 102686. doi: https://doi.org/10.1016/j.asej.2024.102686
Nikoo, M. R. et al. (2026) 'Assessing the fidelity of multi-satellite precipitation estimates for drought monitoring in a mountain water tower to arid basin system', Journal of Arid Environments, 232, p. 105519. doi:https://doi.org/10.1016/j.jaridenv.2025.105519
Saracoglu, F. A., and Kaynar, Y. A. (2025) 'Assessment of Drought Indices Based on Effective Precipitation: A Case Study from Çanakkale, a Humid Region in Türkiye', Sustainability, 17(22), pp. 1-26. doi: https://doi.org/10.3390/su172210080
Sosa, G., Fernández‑Long, M. E., and Vicente‑Serrano, S. M. (2025) 'Evaluating the performance of drought indices for assessing agricultural droughts in Argentina', Agronomy Journal, 117(1), pp. 1-15. doi: https://doi.org/10.1002/agj2.70008
Tigkas, D., Vangelis, H. and Tsakiris, G. (2019) 'Drought characterisation based on an agriculture-oriented standardised precipitation index', Theoretical and applied climatology, 135, pp. 1435-1447. doi: https://doi.org/10.1007/s00704-018-2451-3
Tigkas, D. et al. (2022) 'Incorporating aSPI and eRDI in drought indices calculator (DrinC) software for agricultural drought characterisation and monitoring', Hydrology, 9(6), pp. 1-14. doi: https://doi.org/10.3390/hydrology9060100
Tosan, M. et al. (2026) 'Spatiotemporal performance and error analysis of satellite precipitation products over a topographically complex semi-arid region in Iran', Journal of Mountain Science, 23, pp. 118–138. doi: https://doi.org/10.1007/s11629-025-9984-6
Tsesmelis, D. et al. (2023) 'Spatiotemporal application of the standardized precipitation index (SPI) in the eastern Mediterranean', Climate, 11(5), pp. 1-23. doi: https://doi.org/10.3390/cli11050095
Wu, J. et al. (2023) 'Correlation of climate change and human activities with agricultural drought and its impact on the net primary production of winter wheat', Journal of Hydrology, 620, p. 129504. doi: https://doi.org/10.1016/j.jhydrol.2023.129504
Yu, H. and Hutson, A. D. (2024) 'Inferential procedures based on the weighted Pearson correlation coefficient test statistic', Journal of applied statistics, 51(3), pp. 481-496. doi:
https://doi.org/10.1080/02664763.2022.2137477
Yu, J. H. et al. (2021) 'Measures to cope with the impact of climate change and drought in the island region: a study of the water literacy awareness, attitude, and behavior of the Taiwanese public', Water, 13(13), p. 1799. doi: https://doi.org/10.3390/w13131799
Yue, Y., Shen, S. H. and Wang, Q. (2018) 'Trend and variability in droughts in Northeast China based on the reconnaissance drought index'. Water, 10(3), pp. 1-17. doi: https://doi.org/10.3390/w10030318
Zarei, A. R., Moghimi, M. M., and Mahmoudi, M. R. (2016) 'Parametric and non-parametric trend of drought in arid and semi-arid regions using RDI index', Water Resources Management, 30, pp. 5479-5500. doi: https://doi.org/10.1007/s11269-016-1501-9
Kwak, S. (2023) 'Are only p-values less than 0.05 significant? A p-value greater than 0.05 is also significant'. Journal of Lipid and Atherosclerosis, 12(2), pp. 89-95. doi: https://doi.org/10.12997/jla.2023.12.2.89
Iacuzzi, N. et al. (2025) 'Crop Water Requirement Estimated with Data-Driven Models Improves the Reliability of CROPWAT 8.0 and the Water Footprint of Processing Tomato Grown in a Hot-Arid Environment', Agronomy, 15(7), pp. 2-19. doi: https://doi.org/10.3390/agronomy15071533
Lee, C. et al. (2023) 'Optimal probability distribution and applicable minimum time-scale for daily standardized precipitation index time series in South Korea'. Atmosphere, 14(8), pp. 1-19. doi: https://doi.org/10.3390/atmos14081292
Li, L. et al. (2024) 'Evolution of drought characteristics and propagation from meteorological to agricultural drought under the influences of climate change and human activities', Environmental Science and Pollution Research, 31(18), pp. 26713-26736. doi: https://doi.org/10.1007/s11356-024-32709-z
Liu, L., and Xu, Z. X. (2016) 'Regionalization of precipitation and the spatiotemporal distribution of extreme precipitation in southwestern China', Natural Hazards, 80, pp. 1195-1211. doi: https://doi.org/10.1007/s11069-015-2018-x
Lornezhad, E., Ebrahimi, H., and Rabieifar, H. (2023) 'Analysis of precipitation trends and characteristics on agricultural water resources in Lorestan province', Journal of Water and Soil Resources Conservation, 13(1), pp. 27-40. doi: https://doi.org/10.30495/wsrcj.2023.69930.11327
Maier, M., and Lakens, D. (2022) 'Justify your alpha: A primer on two practical approaches', Advances in Methods and Practices in Psychological Science, 5(2), pp. 1-14. doi: https://doi.org/10.1177/25152459221080396
Patel, R., and Patel, A. (2024) 'Evaluating the impact of climate change on drought risk in semi-arid region using GIS technique'. Results in Engineering, 21, p. 101957. doi: https://doi.org/10.1016/j.rineng.2024.101957
Polroudimoghadam, M., Hamzeh, S. and Vazifehdoust, M. (2016) 'Investigating the trend of rainfall and runoff changes using the Global Land Data Assimilation System (GLDAS) in Doosti Dam Basin'. Scientific- Research Quarterly of Geographical Data, 25(98), pp. 43-56. doi: https://doi.org/10.22131/sepehr.2016.22137
Raeesi, M. et al. (2023) 'Estimation of vegetation changes concerning annual rainfall and temperature in Semnan Province', Journal of Environmental Erosion Research, 13 (4), pp. 56-82. doi: http://dx.doi.org/10.61186/jeer.13.4.56
Rahmani, Z. and Ahmadi, J. (2024) 'The impact of human activities on climate change', Sprin Journal of Arts, Humanities and Social Sciences, 3(6), pp. 24-27. doi: https://doi.org/10.55559/sjahss.v3i6.362
Rezaei, M. et al. (2024) 'Prediction of agricultural drought index in a hot and dry climate using advanced hybrid machine learning'. Ain Shams Engineering Journal, 15(5), p. 102686. doi: https://doi.org/10.1016/j.asej.2024.102686
Nikoo, M. R. et al. (2026) 'Assessing the fidelity of multi-satellite precipitation estimates for drought monitoring in a mountain water tower to arid basin system', Journal of Arid Environments, 232, p. 105519. doi:https://doi.org/10.1016/j.jaridenv.2025.105519
Saracoglu, F. A., and Kaynar, Y. A. (2025) 'Assessment of Drought Indices Based on Effective Precipitation: A Case Study from Çanakkale, a Humid Region in Türkiye', Sustainability, 17(22), pp. 1-26. doi: https://doi.org/10.3390/su172210080
Sosa, G., Fernández‑Long, M. E., and Vicente‑Serrano, S. M. (2025) 'Evaluating the performance of drought indices for assessing agricultural droughts in Argentina', Agronomy Journal, 117(1), pp. 1-15. doi: https://doi.org/10.1002/agj2.70008
Tigkas, D., Vangelis, H. and Tsakiris, G. (2019) 'Drought characterisation based on an agriculture-oriented standardised precipitation index', Theoretical and applied climatology, 135, pp. 1435-1447. doi: https://doi.org/10.1007/s00704-018-2451-3
Tigkas, D. et al. (2022) 'Incorporating aSPI and eRDI in drought indices calculator (DrinC) software for agricultural drought characterisation and monitoring', Hydrology, 9(6), pp. 1-14. doi: https://doi.org/10.3390/hydrology9060100
Tosan, M. et al. (2026) 'Spatiotemporal performance and error analysis of satellite precipitation products over a topographically complex semi-arid region in Iran', Journal of Mountain Science, 23, pp. 118–138. doi: https://doi.org/10.1007/s11629-025-9984-6
Tsesmelis, D. et al. (2023) 'Spatiotemporal application of the standardized precipitation index (SPI) in the eastern Mediterranean', Climate, 11(5), pp. 1-23. doi: https://doi.org/10.3390/cli11050095
Wu, J. et al. (2023) 'Correlation of climate change and human activities with agricultural drought and its impact on the net primary production of winter wheat', Journal of Hydrology, 620, p. 129504. doi: https://doi.org/10.1016/j.jhydrol.2023.129504
Yu, H. and Hutson, A. D. (2024) 'Inferential procedures based on the weighted Pearson correlation coefficient test statistic', Journal of applied statistics, 51(3), pp. 481-496. doi:
https://doi.org/10.1080/02664763.2022.2137477
Yu, J. H. et al. (2021) 'Measures to cope with the impact of climate change and drought in the island region: a study of the water literacy awareness, attitude, and behavior of the Taiwanese public', Water, 13(13), p. 1799. doi: https://doi.org/10.3390/w13131799
Yue, Y., Shen, S. H. and Wang, Q. (2018) 'Trend and variability in droughts in Northeast China based on the reconnaissance drought index'. Water, 10(3), pp. 1-17. doi: https://doi.org/10.3390/w10030318
Zarei, A. R., Moghimi, M. M., and Mahmoudi, M. R. (2016) 'Parametric and non-parametric trend of drought in arid and semi-arid regions using RDI index', Water Resources Management, 30, pp. 5479-5500. doi: https://doi.org/10.1007/s11269-016-1501-9
)