摘要：Drought events are of great importance in most Mediterranean climate regionsbecause of the diverse and costly impacts they have in various economicsectors and on the environment. The effects of this natural hazard onrainfed crops are particularly evident. In this study the impacts of droughton two representative rainfed crops in Spain (wheat and barley) wereassessed. As the agriculture sector is vulnerable to climate, it isespecially important to identify the most appropriate tools for monitoringthe impact of the weather on crops, and particularly the impact of drought.Drought indices are the most effective tool for that purpose. Variousdrought indices have been used to assess the influence of drought on cropyields in Spain, including the Standardized Precipitation Evapotranspiration Index (SPEI), the Standardized Precipitation Index (SPI),the Palmer drought indices (PalmerDrought Severity Index, PDSI; Palmer Z Index, Z Index; Palmer Hydrological Drought Index, PHDI; Palmer Modified Drought Index, PMDI), and the StandardizedPalmer Drought Index (SPDI). Two sets of crop yield data at differentspatial scales and temporal periods were used in the analysis. The resultsshowed that drought indices calculated at different timescales (SPI, SPEI)most closely correlated with crop yield. The results also suggested thatdifferent patterns of yield response to drought occurred depending on theregion, period of the year, and the drought timescale. The differingresponses across the country were related to season and the magnitude ofvarious climate variables.
