Chapter 46 - Drought assessment using the standardized precipitation index (SPI) in GIS environment in Greece

Abstract

The scope of the present research is to assess drought events using the Standardized Precipitation Index (SPI), which can provide accurate results of drought features on a spatiotemporal scale for Greece. The climate in Greece is a typical northern Mediterranean, with most of the rainfall events noted throughout the period between November and April, with hot and arid summers. However, owing to their unique topography, Hellenic territories have a significant variety of microclimates. Moreover, in western Greece (Region of Epirus), Pindus starts from north to south and has a wet climate with maritime features. SPI is a useful tool, and its importance can be noted in its clarity and power to recognize the severity, duration, and extent of a drought phenomenon. In addition, an alert drought warning system may be combined with contingency planning and water resource planning. In this context, the study area, as it often faces devastating drought damage and impacts, offers a very suitable opportunity for this application. The proposed methodology studies the SPI calculation for all Hellenic territories, and it was evaluated using precipitation time-series data. The selected calibrated SPI application covers the period 1981–2010 using data from 33 precipitation stations and time scales of 6 and 12months. The SPI is calculated using software developed by the DMCSEE Project. Then, the spatial transformation of the SPI outputs was achieved using geostatistical methods using geographical information systems. Based on the index results, the drought years were 1989–90, 1992–93, 2000, and 2007–08 with the most severe event, both in duration and intensity, were in 1989–90. The SPI results underline its potential in a drought warning system and forecasting attempt as part of a sustainable drought contingency planning effort.