Mathbout S, Lopez-Bustins JA, Martin-Vide J, Bech J, Rodrigo FS (2018) Spatial and temporal analysis of drought variability at several time scales in Syria during 1961–2012. Atmospheric Research. 200,153-168
This paper analyses the observed spatiotemporal characteristics of drought phenomenon in Syria using the Standardised Precipitation Index (SPI) and the Standardised Precipitation Evapotranspiration Index (SPEI). Temporal variability of drought is calculated for various time scales (3, 6, 9, 12, and 24 months) for 20 weather stations over the 1961–2012 period. The spatial patterns of drought were identified by applying a Principal Component Analysis (PCA) to the SPI and SPEI values at different time scales. The results revealed three het- erogeneous and spatially well-defined regions with different temporal evolution of droughts: 1) Northeastern (inland desert); 2) Southern (mountainous landscape); 3) Northwestern (Mediterranean coast). The evolutionary characteristics of drought during 1961–2012 were analysed including spatial and temporal variability of SPI and SPEI, the frequency distribution, and the drought duration. The results of the non-parametric Mann–Kendall test applied to the SPI and SPEI series indicate prevailing significant negative trends (drought) at all stations. Both drought indices have been correlated both on spatial and temporal scales and they are highly comparable, especially, over a 12 and 24 month accumulation period. We concluded that the temporal and spatial char- acteristics of the SPI and SPEI can be used for developing a drought intensity – areal extent – and frequency curve that assesses the variability of regional droughts in Syria. The analysis of both indices suggests that all three regions had a severe drought in the 1990s, which had never been observed before in the country. Furthermore, the 2007–2010 drought was the driest period in the instrumental record, happening just before the onset of the recent conflict in Syria.
The Eastern Mediterranean is one of the most prominent hot spots of climate change in the world and extreme climatic phenomena in this region such as drought or extreme rainfall events are expected to become more frequent and intense. In this study climate extreme indices recommended by the joint World Meteorological Organization Expert Team on Climate Change Detection and Indices are calculated for daily precipitation data in 70 weather stations during 1961–2012. Observed trends and changes in daily precipitation extremes over the EM basin were analysed using the RClimDex package, which was developed by the Climate Research Branch of the Meteorological Service of Canada. Extreme and heavy precipitation events showed globally a statistically significant decrease in the Eastern Mediterranean and, in the southern parts, a significant decrease in total precipitation. The overall analysis of extreme precipitation indices reveals that decreasing trends are generally more frequent than increasing trends. We found statistically significant decreasing trends (reaching 74% of stations for extremely wet days) and increasing trends (reaching 36% of stations for number of very heavy precipitation days). Finally, most of the extreme precipitation indices have a statistically significant positive correlation with annual precipitation, particularly the number of heavy and very heavy precipitation days.