Precipitation variation and water balance evaluation using different indices




SPEI, water balance, NDVI, trend analysis, Romania


The study evaluates the variability of water balance using different indices for the period 1961–2018 in Cotnari and surroundings, in the middle part of the Moldavian Plateau (MP), Romania. With the aid of statistical analysis and remote sensing, we discovered that the Cotnari's SPEI (Standardized Precipitation and Evapotranspiration Index) variability is characterized by severe values that alternate between significant excess and significant deficits. According to SPEI, between 57.2 and 61.4% of the months were near normal in terms of water balance. There were between 19.3 and 25.1% months with water excess and between 17.1 and 20.8% with water deficit. The links between NDVI and SPEI become stronger as SPEI reaches extreme values (above 1.5 units or below −1.5 units). The water balance indicates a decrease in available water resources.


Download data is not yet available.

Author Biography

Emilian Viorel Mihăilă, Alexandru Ioan Cuza University of Iași, Iași, Romania




Angearu, C. V., Ontel, I., Boldeanu, G., Mihăilescu, D., Nertan, A., Crăciunescu, V., Catană, S. et al. 2020: Multi-temporal analysis and trends of the drought based on MODIS data in agricultural areas, Romania. Remote Sensing 12-23. DOI:

Apopei, L. M., Mihăilă, D., Bistricean, P. I. 2020: Thermo-hydrometric arguments in the demonstration of foehnal circulation in Cotnari, Romania. Geobalcanica, Proceedings 2020. Ohrid. DOI:

Bandoc, G., Prăvălie, R. 2015: Climatic water balance dynamics over the last five decades in Romania’s most arid region, Dobrogea. Journal of Geographical Sciences 25. DOI:

Bannari, A., Morin, D., Bonn, F., Huete, A. R. 1995: A review of vegetation indices. Remote Sensing Reviews 13-1,2. DOI:

Beguería, S., Vicente-Serrano, S. M., Reig, F., Latorre, B. 2014: Standardized precipitation evapotranspiration index (SPEI) revisited: parameter fitting, evapotranspiration models, tools, datasets and drought monitoring. International Journal of Climatology 34. DOI:

Bordun, C., Nertan, A. T., Cimpeanu, S. M. 2018: Evolution of vegetation fraction cover in agricultural areas affected by prolonged droughts in the south regions of Romania. Agriculture for Life, Life for Agriculture Conference Proceedings.

Boroneant, C., Ionita, M., Brunet, M., Rimbu, N. 2011: CLIVAR-SPAIN contributions: seasonal drought variability over the Iberian Peninsula and its relationship to global sea surface temperature and large scale atmospheric circulation. WCRP OSC: Climate Research in Service to Society, Denver.

Chavez, J. P. S. 1996: Image-based atmospheric corrections – revisited and improved. Photogrammetric Engineering and Remote Sensing 62-9.

Cheval, S. 2015: The standardized precipitation index – an overview. Romanian Journal of Meteorology 12-1,2.

Cotea, V. D., Ciubotaru, M., Barbu, N. N., Cotea, V. V., Magazin, G. P., Grigorescu, C. C. 2006: Podgoria Cotnari / Cotnari vineyard. Bucureşti.

Dascălu, S. I., Gothard, M., Bojariu, R., Birsan M. V., Cică, R., Vintilă, R., Adler, M. J. et al. 2016: Drought-related variables over the Bârlad basin (Eastern Romania) under climate change scenarios. Catena 141. DOI:

Dobri, R. V., Sfîcă, L., Amihăesei, V. A., Apostol, L., Țîmpu, S. 2021: Drought extent and severity on arable lands in Romania derived from normalized difference drought index (2001–2020). Remote Sensing 13-8. DOI:

Dragotă, C. S., Mărculeţ, C., Mic, E. L., Grofu, A. 2012: Mapping dryness time-scales in the curvature Carpathians and Subcarpathians (Romania) by the standardized precipitation index. Romanian Journal of Geography 56-2.

Dukat, P., Bednorz, E., Ziemblińska, K., Urbaniak, M. 2022: Trends in drought occurrence and severity at mid-latitude European stations (1951–2015) estimated using standardized precipitation (SPI) and precipitation and evapotranspiration (SPEI) indices. Meteorology and Atmospheric Physics 134-20. DOI:

Hakam, O., Baali, A., El Kamel, T., Ahouach, Y., Azennoud, K. 2022: Comparative evaluation of various drought indices (DIs) to monitor drought status: A case study of Moroccan Lower Sebou basin. Kuwait Journal of Science 49-3. DOI:

Jianqing, Z., Jinlong, H., Buda, S., Lige, C., Yanjun, W., Tong, J., Fischer, T. 2016: Intensity, area and duration analysis of droughts in China 1960–2013. Climate Dynamics 48. DOI:

Kendall, M. G. 1975: Rank correlation methods. London.

Kingston, D. G., Stagge, J. H., Tallaksen, L. M., Hannah, D. M. 2015: European-scale drought: Understanding connections between atmospheric circulation and meteorological drought indices. Journal of Climate 28. DOI:

Mann, H. B. 1945: Nonparametric tests against trend. Econometrica 13-3. DOI:

Mihai, L., Stancalie, A., Sporea, A., Sporea, D., Nertan, A., Mihailescu, D. 2016: Drought vegetation monitoring using in situ and satellite data, in the Caracal plain of Romania. Romanian Reports in Physics 68-2.

Mihăilă, D. 2006: Câmpia Moldovei-studiu climatic. Suceava.

Mihăilă, D., Bistricean, P. I., Lazurca, L. G., Briciu, A. E. 2017: Climatic water deficit and surplus between the Carpathian Mountains and the Dniester River (1961–2012). Environmental Monitoring and Assessment 189. DOI:

Mihăilă, D., Briciu, A. E. 2012: Actual climate evolution in the NE Romania. Manifestations and consequences, 12th International Multidisciplinary Scientific GeoConference, SGEM Conference Proceedings, 4. Albena.

Mihăilă, D., Tanasă, I. 2013: The characteristics of the atmospheric precipitating during the hot season of the year in the Plateau of Suceava. Present Environment & Sustainable Development 7-2.

Milanović, M., Micić, T., Lukić, T., Nenadović, S. S., Basarin, B., Filipović, D., Tomić, M. et al. 2019: Application of Landsat-derived NDVI in monitoring and assessment of vegetation cover changes in Central Serbia. Carpathian Journal of Earth and Environmental Sciences 14-1. DOI:

Morar, C., Lukić, T., Basarin, B., Valjarević, A., Vujičić, M., Niemets, L., Telebienieva, I. et al. 2021: Shaping sustainable urban environments by addressing the hydro-meteorological factors in landslide occurrence: Ciuperca Hill (Oradea, Romania). International Journal of Environmental Research and Public Health 18-9. DOI:

Neadealcov, M., Răileanu, V., Sîrbu, R., Cojocariu, R. 2015: The use of standardized indicators (SPI and SPEI) in predicting droughts over the Republic of Moldova territory. Present Environment & Sustainable Development 9-2. DOI:

Ontel, I., Irimescu, A., Boldeanu, G., Mihailescu, D., Angearu, C. V., Nertan, A., Craciunescu, V. et al. 2021: Assessment of soil moisture anomaly sensitivity to detect drought spatio-temporal variability in Romania. Sensors 21-24. DOI:

Pascoa, P., Gouveia, C., Russo, C. A., Bojariu, R., Vicente-Serrano, M. S., Trigo, M. R. 2020: Drought impacts on vegetation in Southeastern Europe. Remote Sensing 12-13. DOI:

Patriche, C. V. 2009: Modele statistice aplicate în climatologie. Iaşi.

Piticar, A. 2013: Studii privind schimbările climatice recente din nord-estul României. Ph.D. thesis, Universitatea Babeş-Bolyai. Cluj-Napoca.

Piticar, A., Mihăilă, D., Lazurca, L. G., Bistricean, P. I., Puțuntică, A., Briciu, A. E. 2016: Spatiotemporal distribution of reference evapotranspiration in the Republic of Moldova. Theoretical and Applied Climatology 124-3. DOI:

Pörtner, H. O., Roberts, D. C., Tignor, M., Poloczanska, E. S., Mintenbeck, K., Alegría, A., Craig, M. et al. 2022: Climate change 2022 – impacts, adaptation and vulnerability. Working Group II contribution to the sixth assessment report of the Intergovernmental Panel on Climate Change. Cambridge, New York. DOI: https://doi:10.1017/9781009325844

Potop, V. 2003: Repartiţia spaţială a secetelor cu grad diferit de intensitate pe teritoriul Republicii Moldova, Proceedings of the Symposium 'GIS', no. 9, Annals of the University "Alexandru Ioan Cuza", Tom XLIX, s.IIc., Geography. Iași.

Potop, V. 2011: Evolution of drought severity and its impact on corn in the Republic of Moldova. Theorethical and Applied Climatology 105-3,4. DOI:

Prăvălie, R., Sîrodoev, I., Peptenatu, D. 2014: Detecting climate change effects on forest ecosystems in Southwestern Romania using Landsat TM NDVI data. Journal of Geographical Sciences 24. DOI:

Roşca, C. F. 2020: Variabilitatea climatică şi efectele induse asupra utilizării terenurilor în Câmpia Română (Sectorul Jiu-Olt). Ph.D. thesis, Universitatea Babeş-Bolyai. Cluj-Napoca.

Rouse, J. W., Haas, H., Schell, J. A., Deering, D. W. 1973: Monitoring vegetation systems in the Great Plains with ERTS. Paper presented at the Third ERTS Symposium. Internet: (3. 6. 2021).

Rouse, J. W., Haas, R. H., Schell, J.A., Deering, D. W., Harlan, J. C. 1974: Monitoring the vernal advancements and retrogradation (greenwave effect) of natural vegetation. NASA/GSFC Final Report, NASA, Greenbelt, MD. Internet: (12. 6. 2021).

Sandu, I. 2008: Clima României. Bucharest.

Sen, P. K. 1968: Estimates of the regression coefficient based on Kendall's Tau. Journal of the American Statistical Association 63-324. DOI:

Sfîcă, L. 2015: Clima Culoarului Siretului şi a regiunilor limitrofe. Ph.D. thesis, Universitatea Alexandru Ioan Cuza Iaşi.

Sfîcă, L., Ichim, P., Apostol, L., Ursu, A. 2018: The extent and intensity of the urban heat island in Iași city, Romania. Theoretical and Applied Climatology 134. DOI:

Spinoni, J., Antofie, T., Barbosa, P., Bihari, Z., Lakatos, M., Szalai, S., Szentimrey, T. et al. 2013: An overview of drought events in the Carpathian Region in 1961–2010. Advances in Science and Research 10. DOI:

Stagge, J. H., Tallakse, T. L., Gudmundsson, L., Van Loon, A. F., Stahl, K. 2015: Candidate distributions for climatological drought indices (SPI and SPEI). International Journal of Climatology 35-13. DOI:

Tănasă, I. 2011: Clima Podişului Sucevei – fenomene de risc, implicaţii în dezvoltarea durabilă. Ph.D. thesis, Universitatea Ștefan cel Mare, Suceava.

Tucker, C. J. 1979: Red and photographic infrared linear combinations for monitoring vegetation. Remote Sensing of Environment 8-2. DOI:

Vicente-Serrano, S. M., Beguería, S., López-Moreno, J. I. 2010: A multi-scalar drought index sensitive to global warming: the standardized precipitation evapotranspiration index. Journal of Climate 23-7. DOI:

Vicente-Serrano, S. M., Beguería, S., Lorenzo-Lacruz, J., Camarero, J. J., López-Moreno, J. I., Azorin-Molina, C., Revuelto, J. et al. 2012: Performance of drought indices for ecological, agricultural, and hydrological applications. Earth Interactions 16. DOI:

Weier, J., Herring, D. 2000: Measuring Vegetation (NDVI & EVI). Nasa Earth Observatory. Washington DC.

World Meteorological Organization 2012: Standardized Precipitation Index User Guide. WMO 1090. Geneva. Internet: (5. 10. 2023).

World Meteorological Organization 2018: Guide to Instruments and Methods of Observation. Volume I – Measurement of Meteorological Variables. WMO 8. Geneva. Internet: (5. 10. 2023).




How to Cite

Apopei, L. M., Mihăilă, D., Lazurca, L. G., Bistricean, P. I., Mihăilă, E. V., Horodnic, V. D., & Emandi, M. E. (2023). Precipitation variation and water balance evaluation using different indices. Acta Geographica Slovenica, 64(1), 41–60.