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  • 1
    Online Resource
    Online Resource
    Accuracy of reference evapotranspiration (ET o ) estimates under data scarcity scenarios in the Iberian Peninsula
    Elsevier BV ; 2017
    In:  Agricultural Water Management Vol. 182 ( 2017-03), p. 103-116
    Details
    In: Agricultural Water Management, Elsevier BV, Vol. 182 ( 2017-03), p. 103-116
    Type of Medium: Online Resource
    ISSN: 0378-3774
    URL: Article
    DOI: 10.1016/j.agwat.2016.12.013
    Language: English
    Publisher: Elsevier BV
    Publication Date: 2017
    detail.hit.zdb_id: 2012450-8
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  • 2
    Online Resource
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    A comparison of temporal variability of observed and model‐based pan evaporation over Uruguay (1973–2014)
    Wiley ; 2018
    In:  International Journal of Climatology Vol. 38, No. 1 ( 2018-01), p. 337-350
    Details
    In: International Journal of Climatology, Wiley, Vol. 38, No. 1 ( 2018-01), p. 337-350
    Abstract: This study analyses variability and trends of atmospheric evaporative demand ( AED ) across Uruguay in the past four decades. Changes were assessed using pan evaporation measurements from 10 meteorological stations and compared to PenPan model calculations, which is a physically based model that employs meteorological data as input. Results demonstrate a high agreement between the observed AED and those estimated from the PenPan model. Both observations and model estimations agree on a high interannual variability in AED , though being statistically insignificant ( p   〉  0.05) at seasonal and annual scales. Given that AED shows high sensitivity to changes in relative humidity and sunshine duration, as a surrogate of solar radiation, the lack of significant trends in the AED observations and estimations over Uruguay can be linked to the insignificant trend found for these climate variables for the period from 1973 to 2014. This is the first study that reports Pan evaporation trends for this part of the world, helping to infill gaps for mid‐latitude Southern Hemisphere areas, which are poorly represented in Pan evaporation trends.
    Type of Medium: Online Resource
    ISSN: 0899-8418 , 1097-0088
    URL: Issue
    URL: Article
    DOI: 10.1002/joc.2018.38.issue-1
    DOI: 10.1002/joc.5179
    RVK:
    RA 1000
    Language: English
    Publisher: Wiley
    Publication Date: 2018
    detail.hit.zdb_id: 1491204-1
    SSG: 14
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  • 3
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    High spatial resolution climatology of drought events for Spain: 1961–2014
    Wiley ; 2019
    In:  International Journal of Climatology Vol. 39, No. 13 ( 2019-11-15), p. 5046-5062
    Details
    In: International Journal of Climatology, Wiley, Vol. 39, No. 13 ( 2019-11-15), p. 5046-5062
    Abstract: This study characterizes the climatology of drought events over the mainland Spain and the Balearic Islands using high‐resolution (1.21 km 2 ) 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.
    Type of Medium: Online Resource
    ISSN: 0899-8418 , 1097-0088
    URL: Issue
    URL: Article
    DOI: 10.1002/joc.v39.13
    DOI: 10.1002/joc.6126
    RVK:
    RA 1000
    Language: English
    Publisher: Wiley
    Publication Date: 2019
    detail.hit.zdb_id: 1491204-1
    SSG: 14
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  • 4
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    Climatology and trends of reference evapotranspiration in Spain
    Wiley ; 2021
    In:  International Journal of Climatology Vol. 41, No. S1 ( 2021-01)
    Details
    In: International Journal of Climatology, Wiley, Vol. 41, No. S1 ( 2021-01)
    Abstract: This study presents a climatology and trend analysis of reference crop evapotranspiration ( ET o ) over continental Spain and the Balearic Islands. Geographic features of the study region play a substantial role in the climatology of ET o . The highest values (in excess of 1,200 mm y −1 ) are found at lower elevations in the south, while the lowest values (less than 900 mm y −1 ) are found in the highest elevations in the north. A deep analysis reveals: (a) a low interannual variability; (b) summer accumulates more than 50% of annual values; and (c) the radiative component contribution is higher than 50%. A positive long‐term trend (1961–2014) has been detected for most of the study area, but showing contrasting situations when shorter periods (20–30 years) are analysed. A short initial period of negative trend was followed by a longer period of a positive trend. We argue that global dimming/brightening played a role in this process, as these two contrasting periods are clearly guided by the radiative component. A seasonal analysis of the trends reveals that spring and summer are the seasons showing the long‐term positive trends. Interestingly, a monthly analysis shows that spring trends are guided by March and April and summer trends are mostly guided by June, which is the month showing the highest relative changes. This could have important consequences for agriculture and natural ecosystems since this month represents the start of the summer (dry) period.
    Type of Medium: Online Resource
    ISSN: 0899-8418 , 1097-0088
    URL: Issue
    URL: Article
    DOI: 10.1002/joc.v41.S1
    DOI: 10.1002/joc.6817
    RVK:
    RA 1000
    Language: English
    Publisher: Wiley
    Publication Date: 2021
    detail.hit.zdb_id: 1491204-1
    SSG: 14
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  • 5
    Online Resource
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    Seasonal temperature trends on the Spanish mainland: A secular study (1916–2015)
    Wiley ; 2021
    In:  International Journal of Climatology Vol. 41, No. 5 ( 2021-04), p. 3071-3084
    Details
    In: International Journal of Climatology, Wiley, Vol. 41, No. 5 ( 2021-04), p. 3071-3084
    Abstract: Trends in seasonal mean values of maximum and minimum temperature are analysed in the Spanish mainland from the new MOTEDAS_century database. This new data set has been developed combining the digitalized archives from the Spanish Meteorological Agency (AEMET) with information retrieved from Annual Books published by the former Meteorological Agency dating back to 1916, and covers the period 1916–2015. In all four seasons, mean seasonal temperature of maximum ( T max) and minimum ( T min) increased. The raising occurred in two main pulses separated by a first pause around the middle of the 20th century, but differed among seasons and also between maximum and minimum temperature. Analysis of the percentage of land affected by significant trends in maximum temperature reveals two increasing phases in spring and summer for T max, and in spring, summer, and autumn for T min. However, winter T max only rose during the recent decades, and autumn T max in the first decades. Negative significant trends were found in extended areas in spring T max, and in spring, autumn, and summer T min, confirming the first pause around the 1940's–1960's. Trends of seasonal mean values of T max and T min are not significant for at least the last 25–35 years of the study period, depending on the season. The areas under significant positive trend are usually more extended for T min than T max at any season and period. Areas with significant trend expand and contract in time according to two spatial gradients: south‐east to north‐west (east‐west) for T max, and west to east for T min. We hypothesize a relationship between atmospheric prevalent advection and relief as triggering factors to understand spatial and temporal differences in seasonal temperatures at regional scale during the 20th century in the Iberian Peninsula.
    Type of Medium: Online Resource
    ISSN: 0899-8418 , 1097-0088
    URL: Issue
    URL: Article
    DOI: 10.1002/joc.v41.5
    DOI: 10.1002/joc.7006
    RVK:
    RA 1000
    Language: English
    Publisher: Wiley
    Publication Date: 2021
    detail.hit.zdb_id: 1491204-1
    SSG: 14
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  • 6
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    Global Assessment of the Standardized Evapotranspiration Deficit Index (SEDI) for Drought Analysis and Monitoring
    American Meteorological Society ; 2018
    In:  Journal of Climate Vol. 31, No. 14 ( 2018-07), p. 5371-5393
    Details
    In: Journal of Climate, American Meteorological Society, Vol. 31, No. 14 ( 2018-07), p. 5371-5393
    Abstract: This article developed and implemented a new methodology for calculating the standardized evapotranspiration deficit index (SEDI) globally based on the log-logistic distribution to fit the evaporation deficit (ED), the difference between actual evapotranspiration (ETa) and atmospheric evaporative demand (AED). Our findings demonstrate that, regardless of the AED dataset used, a log-logistic distribution most optimally fitted the ED time series. As such, in many regions across the terrestrial globe, the SEDI is insensitive to the AED method used for calculation, with the exception of winter months and boreal regions. The SEDI showed significant correlations ( p 〈 0.05) with the standardized precipitation evapotranspiration index (SPEI) across a wide range of regions, particularly for short ( 〈 3 month) SPEI time scales. This work provides a robust approach for calculating spatially and temporally comparable SEDI estimates, regardless of the climate region and land surface conditions, and it assesses the performance and the applicability of the SEDI to quantify drought severity across varying crop and natural vegetation areas.
    Type of Medium: Online Resource
    ISSN: 0894-8755 , 1520-0442
    URL: Article
    URL: Article
    DOI: 10.1175/JCLI-D-17-0775.1
    DOI: 10.1175/JCLI-D-17-0775.s1
    RVK:
    UA 4548
    Language: English
    Publisher: American Meteorological Society
    Publication Date: 2018
    detail.hit.zdb_id: 246750-1
    detail.hit.zdb_id: 2021723-7
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  • 7
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    Gap Filling of Monthly Temperature Data and Its Effect on Climatic Variability and Trends
    American Meteorological Society ; 2019
    In:  Journal of Climate Vol. 32, No. 22 ( 2019-11-15), p. 7797-7821
    Details
    In: Journal of Climate, American Meteorological Society, Vol. 32, No. 22 ( 2019-11-15), p. 7797-7821
    Abstract: Observational datasets of climatic variables are frequently composed of fragmentary time series covering different time spans and plagued with data gaps. Most statistical methods and environmental models, however, require serially complete data, so gap filling is a routine procedure. However, very often this preliminary stage is undertaken with no consideration of the potentially adverse effects that it can have on further analyses. In addition to numerical effects and trade-offs that are inherent to any imputation method, observational climatic datasets often exhibit temporal changes in the number of available records, which result in further spurious effects if the gap-filling process is sensitive to it. We examined the effect of data reconstruction in a large dataset of monthly temperature records spanning over several decades, during which substantial changes occurred in terms of data availability. We made a thorough analysis in terms of goodness of fit (mean error) and bias in the first two moments (mean and variance), in the extreme quantiles, and in long-term trend magnitude and significance. We show that gap filling may result in biases in the mean and the variance of the reconstructed series, and also in the magnitude and significance of temporal trends. Introduction of a two-step bias correction in the gap-filling process solved some of these problems, although it did not allow us to produce completely unbiased trend estimates. Using only one (the best) neighbor and performing a one-step bias correction, being a simpler approach, closely rivaled this method, although it had similar problems with trend estimates. A trade-off must be assumed between goodness of fit (error minimization) and variance bias.
    Type of Medium: Online Resource
    ISSN: 0894-8755 , 1520-0442
    URL: Article
    URL: Article
    DOI: 10.1175/JCLI-D-19-0244.1
    DOI: 10.1175/jcli-d-19-0244.s1
    RVK:
    UA 4548
    Language: English
    Publisher: American Meteorological Society
    Publication Date: 2019
    detail.hit.zdb_id: 246750-1
    detail.hit.zdb_id: 2021723-7
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  • 8
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    A high-resolution spatial assessment of the impacts of drought variability on vegetation activity in Spain from 1981 to 2015
    Copernicus GmbH ; 2019
    In:  Natural Hazards and Earth System Sciences Vol. 19, No. 6 ( 2019-06-17), p. 1189-1213
    Details
    In: Natural Hazards and Earth System Sciences, Copernicus GmbH, Vol. 19, No. 6 ( 2019-06-17), p. 1189-1213
    Abstract: Abstract. Drought is a major driver of vegetation activity in Spain, with significant impacts on crop yield, forest growth, and the occurrence of forest fires. Nonetheless, the sensitivity of vegetation to drought conditions differs largely amongst vegetation types and climates. We used a high-resolution (1.1 km) spatial dataset of the normalized difference vegetation index (NDVI) for the whole of Spain spanning the period from 1981 to 2015, combined with a dataset of the standardized precipitation evapotranspiration index (SPEI) to assess the sensitivity of vegetation types to drought across Spain. Specifically, this study explores the drought timescales at which vegetation activity shows its highest response to drought severity at different moments of the year. Results demonstrate that – over large areas of Spain – vegetation activity is controlled largely by the interannual variability of drought. More than 90 % of the land areas exhibited statistically significant positive correlations between the NDVI and the SPEI during dry summers (JJA). Nevertheless, there are some considerable spatio-temporal variations, which can be linked to differences in land cover and aridity conditions. In comparison to other climatic regions across Spain, results indicate that vegetation types located in arid regions showed the strongest response to drought. Importantly, this study stresses that the timescale at which drought is assessed is a dominant factor in understanding the different responses of vegetation activity to drought.
    Type of Medium: Online Resource
    ISSN: 1684-9981
    URL: Article
    URL: Article
    DOI: 10.5194/nhess-19-1189-2019
    DOI: 10.5194/nhess-19-1189-2019-supplement
    Language: English
    Publisher: Copernicus GmbH
    Publication Date: 2019
    detail.hit.zdb_id: 2069216-X
    detail.hit.zdb_id: 2064587-9
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  • 9
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    Reference crop evapotranspiration database in Spain (1961–2014)
    Copernicus GmbH ; 2019
    In:  Earth System Science Data Vol. 11, No. 4 ( 2019-12-13), p. 1917-1930
    Details
    In: Earth System Science Data, Copernicus GmbH, Vol. 11, No. 4 ( 2019-12-13), p. 1917-1930
    Abstract: Abstract. Obtaining climate grids describing distinct variables is important for developing better climate studies. These grids are also useful products for other researchers and end users. The atmospheric evaporative demand (AED) may be measured in terms of the reference evapotranspiration (ETo), a key variable for understanding water and energy terrestrial balances and an important variable in climatology, hydrology and agronomy. Despite its importance, the calculation of ETo is not commonly undertaken, mainly because datasets consisting of a high number of climate variables are required and some of the required variables are not commonly available. To address this problem, a strategy based on the spatial interpolation of climate variables prior to the calculation of ETo using FAO-56 Penman–Monteith equation was followed to obtain an ETo database for continental Spain and the Balearic Islands, covering the 1961–2014 period at a spatial resolution of 1.1 km and at a weekly temporal resolution. In this database, values for the radiative and aerodynamic components as well as the estimated uncertainty related to ETo were also provided. This database is available for download in the Network Common Data Form (netCDF) at https://doi.org/10.20350/digitalCSIC/8615 (Tomas-Burguera et al., 2019). A map visualization tool (http://speto.csic.es, last access: 10 December 2019) is available to help users download the data corresponding to one specific point in comma-separated values (csv) format. A relevant number of research areas could take advantage of this database. For example, (i) studies of the Budyko curve, which relates rainfall data to the evapotranspiration and AED at the watershed scale, (ii) calculations of drought indices using AED data, such as the Standardized Precipitation–Evapotranspiration Index (SPEI) or Palmer Drought Severity Index (PDSI), (iii) agroclimatic studies related to irrigation requirements, (iv) validation of climate models' water and energy balance, and (v) studies of the impacts of climate change in terms of the AED.
    Type of Medium: Online Resource
    ISSN: 1866-3516
    URL: Article
    DOI: 10.5194/essd-11-1917-2019
    Language: English
    Publisher: Copernicus GmbH
    Publication Date: 2019
    detail.hit.zdb_id: 2475469-9
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  • 10
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    Recent changes of relative humidity: regional connections with land and ocean processes
    Copernicus GmbH ; 2018
    In:  Earth System Dynamics Vol. 9, No. 2 ( 2018-06-29), p. 915-937
    Details
    In: Earth System Dynamics, Copernicus GmbH, Vol. 9, No. 2 ( 2018-06-29), p. 915-937
    Abstract: Abstract. We analyzed changes in surface relative humidity (RH) at the global scale from 1979 to 2014 using both observations and the ERA-Interim dataset. We compared the variability and trends in RH with those of land evapotranspiration and ocean evaporation in moisture source areas across a range of selected regions worldwide. The sources of moisture for each particular region were identified by integrating different observational data and model outputs into a Lagrangian approach. The aim was to account for the possible role of changes in air temperature over land, in comparison to sea surface temperature (SST), but also the role of land evapotranspiration and the ocean evaporation on RH variability. The results demonstrate that the patterns of the observed trends in RH at the global scale cannot be linked to a particular individual physical mechanism. Our results also stress that the different hypotheses that may explain the decrease in RH under a global warming scenario could act together to explain recent RH trends. Albeit with uncertainty in establishing a direct causality between RH trends and the different empirical moisture sources, we found that the observed decrease in RH in some regions can be linked to lower water supply from land evapotranspiration. In contrast, the empirical relationships also suggest that RH trends in other target regions are mainly explained by the dynamic and thermodynamic mechanisms related to the moisture supply from the oceanic source regions. Overall, while this work gives insights into the connections between RH trends and oceanic and continental processes at the global scale, further investigation is still desired to assess the contribution of both dynamic and thermodynamic factors to the evolution of RH over continental regions.
    Type of Medium: Online Resource
    ISSN: 2190-4987
    URL: Article
    URL: Article
    DOI: 10.5194/esd-9-915-2018
    DOI: 10.5194/esd-9-915-2018-supplement
    Language: English
    Publisher: Copernicus GmbH
    Publication Date: 2018
    detail.hit.zdb_id: 2578793-7
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