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© Author(s) 2010. CC Attribution 3.0 License. This work has been supported by the "Salva-Sinobas project: Climatic Variability Characterization in the Iberian Peninsula during the Period 1750-1850" financed by the Ministry of the Environment, Rural and Maritime Affairs of Spain (ref. 200800050083542). We want to thank Sergio Vicente Serrano and José María Cuadrats for providing the Zaragoza rogation data used in this work. Also the authors appreciate the helpful and constructive comments of both reviewers (Fredrik Charpentier Ljungqvist and Philip Brohan)., In this paper, series of drought occurrence and drought extension in the Iberian Peninsula are constructed for the 1600-1750 period from seven rogation series. These rogation ceremony records come from Bilbao, Catalonia, Zamora, Zaragoza, Toledo, Murcia and Seville. They are distributed across the Peninsula and include the areas with the most characteristic Iberian climate types, influenced by the Atlantic and the Mediterranean conditions, described from modern data. A seasonal division of the series shows that spring is a critical season for rogation series in most of Iberia, being Bilbao the only site were the highest number of rogations is detected for a different season. The annual analysis of the series shows a dramatic difference between the first half of the 17th century when droughts are characterized by its local character; and the rest of the period, when they affect to broader regions or even to the whole Peninsula. The analysis of spring series confirms the existence of the two periods detected in the annual analysis. Finally, secondary documentary sources are used to further characterise the two most extended droughts in the period, 1664 and 1680, and to verify the extension of the areas affected by droughts recorded through rogation series., Ministerio de Agricultura, Alimentación y Medio Ambiente (MARM), España, Depto. de Física de la Tierra y Astrofísica, Fac. de Ciencias Físicas, TRUE, pub

© Universidad de la Rioja. Fernando Domínguez Castro was supported by the Ecuatorian Government (Secretaría de Educación superior, Ciencia, Tecnología e Innovación) through a PROMETEO project., Droughts are probably the natural hazard with the highest socioeconomic impact. Simultaneously, they are a very complex phenomenon; they are triggered by a diversity of physical factors and occur at a variety of time scales. Consequently, the instrumental record currently available is too short and the characterization of its multidecadal variability requires the use of natural proxies (tree rings, sedimentary records) or documentary sources. In this paper we analyse three documentary sources with potential to analyse the long-term variability of droughts: chapter acts, logbooks and chronicles. The chapter acts recorded discussions and decisions made during the assemblies of the local authorities and provide continuous and direct evidence on drought impacts. They are especially useful to study droughts between the 15th and the 19th centuries in Europe and the 17th to 18th in the former colonies. Logbooks recorded the meteorological conditions and the incidents occurred during navigation. They provide indirect information through the circulation indices that can be very helpful to understand the mechanisms and teleconnections associated to droughts. Finally, the chronicles are historiographical documents describing political and social events. They are secondary sources and the references to climatic events are discontinuous, thus their analysis must be extremely careful, but they are especially useful to study specific drought events especially prior to 15th century when no other sources are available., Las sequías son uno de los riesgos naturales que mayor impacto causan en la población y en la economía, por lo que estudiarlas es fundamental para poder implementar medidas de prevención y adaptación a las mismas. Sin embargo, son un fenómeno climático muy complejo que ocurre a distintas escalas temporales y se desencadena por una amplia variedad de factores físicos. El registro instrumental del que se dispone actualmente no es suficientemente largo para estudiar en detalle las sequías, especialmente su variabilidad multidecadal por lo que se hace necesario recurrir a otras fuentes de información como los proxies naturales (anillos de los árboles, registros sedimentarios…) o las fuentes documentales. En este trabajo analizamos tres fuentes documentales con potencial en el estudio de la variabilidad multidecadal de las sequías: actas capitulares, diarios de navegación y crónicas. Las actas capitulares registran las discusiones y decisiones tomadas por los gobiernos locales en sus reuniones. Destacan debido a que proporcionan información continua y directa sobre los impactos de las sequías y son de especial relevancia entre los siglos XV y XIX en Europa y en los siglos XVII y XVIII en las colonias. Los diarios de navegación son los registros que elaboran los navegantes durante sus rutas, en los que registran las condiciones meteorológicas de las mismas y los incidentes ocurridos. Presentan información indirecta de índices de circulación especialmente interesantes para entender los mecanismos y teleconexiones asociados a las sequías. Por último, las crónicas son documentos historiográficos que se realizan con el objetivo de describir eventos políticos y sociales. Sin embargo, se trata de fuentes documentales secundarias, donde las referencias a eventos climáticos son discontinuas. Por ello, deben ser tratadas con cautela. Las crónicas no son de gran utilidad para estudiar la variabilidad de las sequías, no obstante pueden ser muy útiles para estudiar eventos de sequía, Secretaría de Educación superior, Ciencia, Tecnología e Innovación (Gobierno de Ecuador), Depto. de Física de la Tierra y Astrofísica, Fac. de Ciencias Físicas, TRUE, pub

© Author(s) 2012. CC Attribution 3.0 License. Authors are grateful to D. Wheeler who provides rainfall data from Gibraltar. This work has been financed by the Ministry of the Environment, Rural and Maritime Affairs of Spain "Salva-Sinobas project: Climatic Variability Characterization in the Iberian Peninsula during the Period 1750-1850" (ref. 200800050083542), Spanish Science and Innovation Ministry (AYA2008-04864/AYA and AYA2011-25945) and MILLENNIUM Project (European Commision, IP 017008-2)., Among the different meteorological hazards, droughts are those with the highest socio-economical impact on the Iberian Peninsula. Drought events have been largely studied in the instrumental period, but very little is known about the characteristics of droughts in the preinstrumental period. In this work, several series of rogation ceremonies are used to identify severe droughts within the period 1750-1850. The overlapping of the rogation series with some instrumental series served to identify some climatic characteristics of rogation ceremonies: (a) during spring, rainfall deficits needed to celebrate rogation ceremonies are smaller than in any other season; (b) the hydrological deficit in a particular region increases with the number of locations celebrating rogations simultaneously. On the other hand, it was found that between 1750-1754 and 1779-1783 are probably the driest periods of the 101 analyzed years. Both show an important number of rogations all over Iberia and during all the seasons. The most extended drought of this period occurred during the spring of 1817, affecting 15 of the 16 locations studied. This drought was influenced by the Tambora eruption (1815). The study of the climate footprint of this eruption and its comparison with similar situations in the series suggest that the spring drought of 1824 may be associated with the eruptions of the Galunggung and Usu volcanoes (1822). Further studies are required to confirm this fact and understand the atmospheric mechanisms involved., Ministerio de Medio Ambiente y Medio Rural y Marino, Ministerio de Ciencia e Innovacion (MICINN), MILLENNIUM Project (European Commision), Unión Europea (UE), Ministerio de Agricultura, Alimentación y Medio Ambiente (MAGRAMA), España, Depto. de Física de la Tierra y Astrofísica, Fac. de Ciencias Físicas, TRUE, pub

There is a growing need for past weather and climate data to support science and decision-making. This paper describes the compilation and construction of a global multivariable (air temperature, pressure, precipitation sum, number of precipitation days) monthly instrumental climate database that encompasses a substantial body of the known early instrumental time series. The dataset contains series compiled from existing databases that start before 1890 (though continuing to the present) as well as a large amount of newly rescued data. All series underwent a quality control procedure and subdaily series were processed to monthly mean values. An inventory was compiled, and the collection was deduplicated based on coordinates and mutual correlations. The data are provided in a common format accompanied by the inventory. The collection totals 12452 meteorological records in 118 countries. The data can be used for climate reconstructions and analyses. It is the most comprehensive global monthly climate dataset for the preindustrial period so far.

© 2022 American Meteorological Society. This research was supported by the Economy and Infrastructure Counselling of the Junta of Extremadura through Grant GR18097 (cofinanced by the European Regional Development Fund). The authors declare that they have no conflicts of interest., Great advances in meteorological science were made in the late eighteenth century. In particular, meteorological instruments were carried on ships and the first systematic meteorological readings over the oceans were made. One of these collections of instrumental meteorological readings was carried out by the Malaspina expedition (1789–94), organized by the Spanish Crown to study its vast possessions around the world. We have recovered meteorological variables such as air temperature (maximum and minimum), atmospheric pressure (maximum and minimum), wind (intensity and direction), and appearance (state of the sky) from the documentation generated by the explorers during the journey. In total, nearly 13,000 instrumental data have been digitized and rescued from this maritime expedition. The comparison of daily temperature and pressure observations with reanalysis and weather stations data shows a good overall agreement. Moreover, apparent discrepancies during several anchored periods have allowed for testing the consistency and quality of these early instrumental marine weather readings., the Economy and Infrastructure Counselling of the Junta of Extremadura, the European Regional Development Fund, Depto. de Física de la Tierra y Astrofísica, Fac. de Ciencias Físicas, TRUE, pub

This study presents a new data set of gauged streamflow (N = 3,224) for Europe spanning the period 1962–2017. The Monthly Streamflow of Europe Dataset (MSED) is freely available at http://msed.csic.es/. Based on this data set, changes in the characteristics of hydrological drought (i.e., frequency, duration, and severity) were assessed for different regions of Europe. Due to the density of the database, it is possible to delimit spatial patterns in hydrological droughts trend with the greatest detail available to date. Results reveal bidirectional changes in monthly streamflow, with negative changes predominating over central and southern Europe, while positive trends dominate over northern Europe. Temporally, two dominant patterns were noted. The first pattern corresponds to a consistent downward trend in all months, evident for southern Europe. A second pattern was noted over central and northern Europe and western France, with a predominant negative trend during warm months and a positive trend in cold months. For hydrological drought events, results suggest a positive trend toward more frequent and severe droughts in southern and central Europe and conversely a negative trend over northern Europe. This study emphasizes that hydrological droughts show complex spatial patterns across Europe over the past six decades, implying that hydrological drought behavior in Europe has a regional character. Accordingly it is challenging to adopt “efficient” strategies and policies to monitor and mitigate drought impacts at the continental level.

This work was supported by the research projects CGL2017-82216-R, PID2019-108589RA-I00 and PCI2019-103631 financed by the Spanish Commission of Science and Technology and FEDER and CROSSDRO project financed by the AXIS (Assessment of Cross(X)-sectoral climate Impacts and pathways for Sustainable transformation), JPI-Climate co-funded call of the European Commission. This study is also supported by "Unidad Asociada CSIC-Universidad de Vigo: Grupo de Física de la Atmósfera y del Oceano". CM acknowledges funding from the Irish Environmental Protection Agency (2019-CCRP-MS.60). LG and RN received partial support from the Xunta de Galicia under the Project ED431C 2017/64-GRC Programa de Consolidación e Estructuración de Unidades de Investigación Competitivas (Grupos de Referencia Competitiva) and Consellería de Educación e Ordenación Universitaria. Previous funders received cofounding from the ERDF, in the agenda of the Operational Program Galicia 2014-2020.", This study provides a long-term (1891-2014) global assessment of precipitation trends using data from two station-based gridded datasets and climate model outputs evolved through the fifth and sixth phases of the Coupled Model Intercomparison Project (CMIP5 and CMIP6, respectively). Our analysis employs a variety of modeling groups that incorporate low- and high-top level members, with the aim of assessing the possible effects of including a well-resolved stratosphere on the model's ability to reproduce long-term observed annual precipitation trends. Results demonstrate that only a few regions show statistically significant differences in precipitation trends between observations and models. Nevertheless, this pattern is mostly caused by the strong interannual variability of precipitation in most of the world regions. Thus, statistically significant model-observation differences on trends (1891-2014) are found at the zonal mean scale. The different model groups clearly fail to reproduce the spatial patterns of annual precipitation trends and the regions where stronger increases or decreases are recorded. This study also stresses that there are no significant differences between low- and high-top models in capturing observed precipitation trends, indicating that having a well-resolved stratosphere has a low impact on the accuracy of precipitation projections., Ministerio de Ciencia e Innovación (MICINN)/FEDER, CROSSDRO project - AXIS (Assessment of Cross(X)-sectoral climate Impacts and pathways for Sustainable transformation), JPI-Climate - call of the European Commission, Unidad Asociada CSIC-Universidad de Vigo: Grupo de Física de la Atmósfera y del Océano, Irish Environmental Protection Agency, Xunta de Galicia, Conselleria de Educacion e Ordenacion Universitaria, Depto. de Física de la Tierra y Astrofísica, Fac. de Ciencias Físicas, TRUE, pub

The performance of a new historical reanalysis, the NOAA-CIRES-DOE 20th Century Reanalysis Version 3 (20CRv3), is evaluated via comparisons with other reanalyses and independent observations. This dataset provides global, 3-hourly estimates of the atmosphere from 1806 to 2015 by assimilating only surface pressure observations and prescribing sea surface temperature, sea ice concentration, and radiative forcings. Comparisons with independent observations, other reanalyses, and satellite products suggest that 20CRv3 can reliably produce atmospheric estimates on scales ranging from weather events to long-term climatic trends. Not only does 20CRv3 recreate a “best estimate” of the weather, including extreme events, it also provides an estimate of its confidence through the use of an ensemble. Surface pressure statistics suggest that these confidence estimates are reliable. Comparisons with independent upper-air observations in the Northern Hemisphere demonstrate that 20CRv3 has skill throughout the 20th century. Upper-air fields from 20CRv3 in the late 20th century and early 21st century correlate well with full-input reanalyses, and the correlation is predicted by the confidence fields from 20CRv3. The skill of analyzed 500hPa geopotential heights from 20CRv3 for 1979-2015 is comparable to that of modern operational 3- to 4-day forecasts. Finally, 20CRv3 performs well on climate timescales. Long time series and multidecadal averages of mass, circulation, and precipitation fields agree well with modern reanalyses and station- and satellite-based products. 20CRv3 is also able to capture trends in tropospheric layer temperatures that correlate well with independent products in the 20th century, placing recent trends in a longer historical context.

We analyzed the impacts of drought severity on a variety of sectors in a topographically complex basin (the upper Aragón basin 2181 km2) in the Central Spanish Pyrenees. Using diverse data sources including meteorological and hydrological observations, remote sensing and tree rings, we analyze the possible hydrological implications of drought occurrence and severity on water availability in various sectors, including downstream impacts on irrigation water supply for crop production. Results suggest varying responses in forest activity, secondary growth, plant phenology, and crop yield to drought impacts. Specifically, meteorological droughts have distinct impacts downstream, mainly due to water partitioning between streamflow and irrigation channels that transport water to crop producing areas. This implies that drought severity can extend beyond the physical boundaries of the basin, with impacts on crop productivity. This complex response to drought impacts makes it difficult to develop objective basin-scale operational definitions for monitoring drought severity. Moreover, given the high spatial variability in responses to drought across sectors, it is difficult to establish reliable drought thresholds from indices that are relevant across all socio-economic sectors. The anthropogenic impacts (e.g. water regulation projects, ecosystem services, land cover and land use changes) pose further challenges to assessing the response of different systems to drought severity. This study stresses the need to consider the seasonality of drought impacts and appropriate drought time scales to adequately assess and understand their complexity

The dynamics of blue and green water partitioning under vegetation and climate change, as well as their different interactions during wet and dry periods, are poorly understood in the literature. We analyzed the impact of vegetation changes on blue water generation in a central Spanish Pyrenees basin undergoing intense afforestation. We found that vegetation change is a key driver of large decreases in blue water availability. The effect of vegetation increase is amplified during dry years, and mainly during the dry season, with streamflow reductions of more than 50%. This pattern can be attributed primarily to increased plant water consumption. Our findings highlight the importance of vegetation changes in reinforcing the decrease in water resource availability. With aridity expected to rise in southern Europe over the next few decades, interactions between climate and land management practices appear to be amplifying future hydrological drought risk in the region.

We present a long-term assessment of precipitation trends in Southwestern Europe (1850–2018) using data from multiple sources, including observations, gridded datasets and global climate model experiments. Contrary to previous investigations based on shorter records, we demonstrate, using new long-term, quality controlled precipitation series, the lack of statistically significant long-term decreasing trends in precipitation for the region. Rather, significant trends were mostly found for shorter periods, highlighting the prevalence of interdecadal and interannual variability at these time-scales. Global climate model outputs from three CMIP experiments are evaluated for periods concurrent with observations. Both the CMIP3 and CMIP5 ensembles show precipitation decline, with only CMIP6 showing agreement with long term trends in observations. However, for both CMIP3 and CMIP5 large interannual and internal variability among ensemble members makes it difficult to identify a trend that is statistically different from observations. Across both observations and models, our results make it difficult to associate any declining trends in precipitation in Southwestern Europe to anthropogenic forcing at this stage.

© 2020, The Author(s). Monitoring and management of several environmental and socioeconomic sectors require climate data that can be summarized using a set of standard and meaningful climate metrics. This study describes a newly developed gridded dataset for the whole of Europe, which employed a set of 125 climate indices spanning different periods based on data availability, but mainly 1950–2017 and 1979–2017. This dataset comprehensively summarizes climate variability in Europe for a wide range of climate variables and conditions, including air temperature, precipitation, biometeorology, aridity, continentality, drought, amongst others. Climate indices were computed at different temporal scales (i.e. monthly, seasonal and annual) and mapped at a grid interval of 0.25°. We intend to update these indices on an annual basis. This dataset is freely available to research and end-user communities.

Three documents describing the Tungurahua eruption of April 23, 1773, have been retrieved. The first one is a report of the eruption that has been translated, while the other two are pictographic documents of high quality. Their analysis provides previously unknown information about this eruption. The volcano was not completely inactive since 1645. The eruption started between 4 and 5 p.m. of April 23 in 1773. The maximum activity occurred during the morning of the 24th and the activity continued for more than a month. The Pastaza River was dammed by rocks and sand during 24 h, being over-flooded for almost 5.6 km. At least two lava flows reached lowlands and run into the Pastaza and Chambo Rivers, respectively. The volcanic ash caused important losses in crops and cattle in an area of more than of 3600 km2 located in the western slope of the volcano. Moreover, our primary sources provide evidences that Cerro Hermoso had an important glacier at that time and that the glacier terminus of the Tungurahua was approximately 148 m below the terminus in the early 1980s. This work is an example that an exhaustive analysis of primary documentary sources allows a better characterization of natural hazards that occurred in historical periods.

Wet and dry extremes in Quito (Ecuador) over the last 400 years are studied using two sources of information: the longest available instrumental rainfall series in northern South America (1891–2015) and the rogation ceremonies recorded in the Chapter Acts of Quito (1600–1822). The rogation ceremonies present a seasonal distribution that is related to the crops and to the typical distribution of rainfall over the year. August was the month with most pro serenitate rogations because farmers needed dry conditions for harvest, whereas excess rainfall at this time would lead to rotting and loss of the harvest. The pro pluvia rogations were markedly more frequent during January and February when farmers needed rain for sowing. This relationship between climate and farming activities makes Quito's rogations a good proxy for drought and extreme wet conditions during January–February–March (JFM) and wet conditions during June–July–August (JJA). Standardized precipitation index (SPI) was computed for the instrumental period. The 3‐month SPI showed a significant linear trend over the last 125 years (−0.4 per decade, p = 0.009). The five wettest periods were 1651–1657, 1663–1669, 1913–1919, 1950–1956, and 1981–1985. Droughts have intensified in frequency and length since the middle of the 20th century. The most important drought periods were 1692–1701, 1718–1723, 1976–1980, 1990–1993, and 2001–2006. The severest drought during the last 400 years occurred in 1692–1701 when a great famine devastated Quito and affected most of the central Andes.