High spatial resolution climatology of drought events for Spain: 1961–2014

Abstract

This study characterizes the climatology of drought events over the mainland Spain and the Balearic Islands using high‐resolution (1.21 km2) meteorological data from 1961 to 2014. The climatology of drought was assessed based on two widely‐recognized drought indices: the Standardized Precipitation Index (SPI) and the Standardized Precipitation‐Evapotranspiration Index (SPEI), considering four different timescales (1‐, 3‐, 6‐ and 12‐months). Drought events were simply defined as sequences of months with negative values of the indices. We analysed the spatial and temporal variability of the frequency, duration and magnitude of the drought events. In general, the frequency of drought events is higher in the northern than in the southern regions. Conversely, the average duration and magnitude of the drought events in central and southwestern regions duplicate those recorded in northern areas. Although drought characteristics exhibit a general north–south gradient irrespective of the drought timescale and the drought index analysed, we found important spatial differences in terms of both drought duration and severity. As opposed to the SPI, the SPEI shows, on average, higher drought durations and magnitudes at 1‐, 3‐ and 6‐months timescales. Albeit of the absence of significant temporal changes in drought duration or magnitude at the regional scale, a nonsignificant tendency toward higher drought duration and magnitude is observed over the majority of Spain. Our result provide valuable guidance to stakeholders and decision‐makers on detecting, monitoring and adapting to drought impacts at local, regional and national scale in Spain.

Pro-Pluvia Rogation Ceremonies in Extremadura (Spain): Are They a Good Proxy of Winter NAO?

“…As we have aforementioned in the discussion of Figure 5, this is very reasonable, because the month in which the rogation is celebrated has less influence in the drought that trigger the rogation than the previous months. Additionally, droughts are long duration events, specifically in southwest of Spain [50].…”

“…The desynchronization between pro-pluvia rogations (celebrated in the month n) and the NAO index (months n-1, n-2 and n-3) can be explained by the long average drought duration in southwest of Spain. The average duration is around 15 weeks in agricultural droughts [50]. In addition, there is a delay of one month between the NAO index and the hydrological variables in the IP.…”

“…These cities are in plane areas, but the annual accumulated precipitation exceeds 1000 mm in mountain areas. Regarding to droughts, Domínguez-Castro et al [50] analyzed the climatology of droughts in Spain based on SPI and SPEI indexes for the period 1961-2014. At scales related with agricultural droughts (3 to 6 months), Extremadura region shows a low number of drought events, The climate of Extremadura is Mediterranean with dry summers and mild winters.…”

Hydrological Characterization of Watering Ponds in Rangeland Farms in the Southwest Iberian Peninsula

“…These low levels of water availability in the ponds represent a problematic situation from the point of view of their role as the main water supply for livestock, not only because of the imminent risk of supply failure, but also because water quality generally deteriorates as the water level in the ponds decreases [10,74,75], with the consequent risk to animal health. This high vulnerability to drought observed in the majority of the ponds, together with the high frequency and severity of these events in the SW Iberian Peninsula [76], questions the use of ponds as the only source of water supply in the farms. This conclusion is in agreement with the results obtained by Pulido-Fernández and Schnabel [1] in a study carried out on a large number of extensive livestock farms in the SW Iberian Peninsula, which revealed that two out of every three farms suffered occasional problems with water supply.…”

High-spatial resolution probability maps of drought duration and magnitude across Spain

“…We obtained the series of peaks-over-threshold (POT) using the series of drought duration and magnitude calculated at 1-, 3-, 6-and 12-month timescales. These series are stationary and do not show any trend (Domínguez-Castro et al, 2018), which is a prerequisite to apply the extreme value theory. The POT series are obtained according to a threshold (x0), as:…”