Document Type : مقاله کوتاه
Associate Professor, Department of Physical Geography, Faculty of Earth Sciences, Shahid Beheshti University, Tehran, Ira
There is a need of monitoring and analysis of drought condition for water resources management. Given the large difficulties to objectively quantify drought characteristics such as duration, intensity, and magnitude several drought indices have been developed in the last decades. One of shortcomings of current drought indices including standardized precipitation index (SPI) is that it does not include water balance by means of evapotranspiration. Standardized precipitation evapotranspiration index (SPEI) includes water balance in calculating of drought index using precipitation and evapotranspiration.The objectives of current study are to investigate meteorological droughts using SPEI in ten synoptic stations in different climates of Iran and to compare the results with SPI. In view of this, temperature and precipitation data in a long term 1975 to 2007 were prepared and the drought indices were calculated. The comparison was done based on indices values and drought categories class. The results showed that both SPI and SPEI indices have significant correlation, moreover the SPEI showed the quick response to drought. The increasing the timescales of indices also increase the duration of drought. Based on the importance of evapotranspiration in arid and semi-arid regions, the SPEI can be used as a suitable index for determining of droughts. However, further researches are needed in spatial and temporal scales.
- Nosrati K. Regional analysis of hydrological drought in Sefidrood Drainage Basin using base flow index. Journal of Range and Watershed Management (Iranian Journal of Natural Resources); 2012; 65(2): 257-267. [In Persian]
- Giorgi F, Lionello P. Climate change projections for the Mediterranean region. Global and Planetary Change; 2008; 63: 90-104.
- Palmer W C. Meteorological drought. U.S. Dept. of Commerce Weather Bureau Research; 1965; Paper 45, p. 58.
- Van Rooy M P. A rainfall anomaly index independent of time and space. Notos; 1965; 14: 43-48.
- Nosrati K, Azarnivand H. Regional analysis of drought severity-duration-return period using precipitation data. Biaban; 2002; 7(1): 49-61. [In Persian]
- Gibbs W J, Maher J V. Rainfall declines as drought indicators. Bureau of Meteorology Bulletin, 1967; 48, Commonwealth of Australia, Melbourne.
- Bahlme H N, Mooley D A. Large-scale droughts/floods and monsoon circulation. Monthly Weather Review; 1980; 108: 1197-1211.
- McKee T B, Doesken N J, Kleist J. The relationship of drought frequency and duration to time scales. Eighth Conference on Applied Climatology, Anaheim, CA, American Meteorological Society; 1993; 179-184.
- Nosrati K, Kazemi Y. Daily monitoring of drought and water resources in different climates of Iran. Journal of Range and Watershed Management (Iranian Journal of Natural Resources); 2011; 64(1): 79-94.
- Nosrati K, Eslamian S, Shahbazi A, Malekian A, Saravi M. M. Application of Daily Water Resources Assessment Model for Monitoring Water Resources Indices. International Journal of Ecological Economics and Statistics; 2009; 13: 88-99.
- Morid S, Smakhtin V, Moghaddasi M. Comparison of seven meteorological indices for drought monitoring in Iran. International Journal of Climatology; 2006; 26(7): 971-985.
- Kempes C, Myers O, Breshears, D, Ebersole J. Comparing response of Pinus edulis tree-ring growth to five alternate moisture indices using historic meteorological data. Journal of Arid Environments; 2008; 72: 350-357.
- Jones P D, Lister D H, Osborn T J, Harpham C, Salmon M, Morice C P. Hemispheric and large-scale land-surface air temperature variations: An extensive revision and an update to 2010. Journal of Geophysical Research; 2012; 117: D05127.
- Sheffield J, Wood E F, Roderick M L. Little change in global drought over the past 60 years. Nature; 2012; 491: 435-438.
- Vicente-Serrano S M, Begueria S, Lopez-Moreno J I. A multiscalar drought index sensitive to global warming: the standardized precipitation evapotranspiration index. Journal of Climate; 2010; 23: 1696-1718.
- Edwards D C, McKee T B. Characteristics of 20th century drought in the United States at multiple time scales. Climatology Report Number 97â2, Department of Atmospheric Science, Colorado State University, Fort Collins, Colorado, 1997. p.155
- Vicente-Serrano S M. Differences in spatial patterns of drought on different time scales: an analysis of the Iberian Peninsula. Water Resources Management; 2006; 20: 37â60.
- Bazrafshan J. The study of some meteorological drought indices in some Iranian climate samples. MSc thesis, University of Tehran, Tehran; 2002. [In Persian]
- Lorenzo-Lacruz J, Vicente-Serrano S M, Lopez-Moreno J I, Begueria S, Garcia-Ruiz J M, Cuadrat J M. The impact of droughts and water management on various hydrological systems in the headwaters of the Tagus River (central Spain). Journal of Hydrology; 2010; 386: 13-26.
- Vicente-Serrano S M, Lopez-Moreno J I, Drummond A, Gimeno L, Nieto R, Moran-Tejeda E, Lorenzo-Lacruz J, Begueria S, Zabalza J. Effects of warming processes on droughts and water resources in the NW Iberian Peninsula (1930-2006). Climate Research; 2011; 48: 203â212.
- Potop V, MoÅ¾nÃ½ M. The application a new drought indexâStandardized precipitation evapotranspiration index in the Czech Republic. Mikroklima a mezoklima krajinnÃ½ch structur a antropogennich prostÅedi; 2011; 2: 2-14.
- Polemio M, Casarano D. Climate change, drought and groundwater availability in southern Italy. Geological Society, London, Special Publications; 2008; 288: 39-51.
- Dai A. Drought under global warming: a review. Wiley Interdisciplinary Reviews: Climate Change; 2011; 2: 45-65.