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CL1.20

While the information, preserved in the records of instrumental measurements, provide an inside view into the history of weather-related extremes of the last 100-150 years or shorter, documentary evidence and the results of natural scientific investigations allow to extend this knowledge several centuries (or millennia) into the past. This concerns, for example those disastrous extremes which were not recorded in the instrumental period, but are known from documentary sources. Compared to palaeo-hydrological investigations of extremes, the papers presented in this session are aimed to provide high-resolution information (with exact dating) based on data derived from documentary evidence, covering a period that does not exceed one-two millennia.
On the one hand, investigations focused on the long-term understanding of variability, changes and shifts in the climatic and/or hydrological regime as well as in the frequency/magnitude of meteorological and hydrological extremes and hazards are welcome. On the other hand, investigations concentrating on one or more great extreme events (extreme cold, heat, floods, droughts etc.) are also invited in the session. Papers discussing the detection of causes of hydrological, meteorological extremes and hazards (environmental, atmospheric/climatic and society-related) in historical times are also addressed and supported to participate in the session. Thus, another important topic of the session is socio-economic responses on extremes or catastrophic events as well as long-term changes, development in cooping weather-related natural hazards. As an integrate part of socio-economic response, the perception and social representation of weather and hydrological hazards and extremes (e.g. floods, droughts) in historical periods are also valuable topics of discussion in the session.
Since this research requires the development of regional chronologies based on good-quality historical sources, besides natural and applied scientists, the active presence and work of historians is of vital importance. The results of historical hydrology investigations and the study of hydro-meteorological extremes in historical times may be utilised in a number of areas such as risk assessment, flood control, hydrological forecasting/predictions, socio-hydrology or in the understanding of the main drivers of hydro-morphological processes.

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Co-organized by HS13
Convener: Andrea Kiss | Co-conveners: Rudolf Brazdil, Mariano Barriendos, Günter Blöschl
Displays
| Attendance Mon, 04 May, 16:15–18:00 (CEST)

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Chat time: Monday, 4 May 2020, 16:15–18:00

D3678 |
EGU2020-586<span style="font-size: .8em!important; font-weight: bold; vertical-align: super; color: green!important;"><span title="Early career scientist: an ECS is an undergraduate or postgraduate (Masters/PhD) student or a scientist who has received their highest degree (BSc, MSc, or PhD) within the past seven years. Provided parental leave fell into that period, up to one year of parental leave time may be added per child, where appropriate.">ECS</span></span>
Annette Sophie Bösmeier, Iso Himmelsbach, and Rüdiger Glaser

Engraved in stone or attached as metal plates to bridges or house walls, flood marks are mostly publicly accessible symbols of high-water level and form part of the cultural heritage. They serve as tangible representations of the extent of past floods and are thus regarded a medium which can raise public risk awareness and contribute to a collective risk memory. Moreover, epigraphic marks are often regarded a valuable source of information on the frequency and magnitude of historical extreme events. However, a flood mark´s informational value may be considered too rudimentary, and the large number of potential error sources is a challenge that often cannot be fully resolved. We therefore conducted a multi-temporal study in the Kinzig catchment, Southwest Germany, in order to, firstly, test for the credibility and the temporal continuity of flood marks. Secondly, we used the knowledge gathered to verify the current flood hazard maps (FHM). For this study, more than 60 flood marks corresponding to 14 events since the beginning of the 19thcentury were checked and/or mapped in three communities in the upper and middle catchment. A detailed historical survey of flood marks dating back to the early 20th century provided a unique opportunity to assess the preservation of marks as well as the extent of relocation since that time. The flood mark heights were then compared with the flooding depths of the modelled FHM for floods between HQ10 and HQextreme at the respective locations. The gauge record was additionally included to assign return periods to the more recent events. Altogether, a high relative agreement between flood marks and the FHM was found in this systematic study, particularly for events during the 20th century. The extreme extents of some events within headwater catchments documented both by epigraphic marks and further documentary sources however appear to be underestimated by the FHM.

How to cite: Bösmeier, A. S., Himmelsbach, I., and Glaser, R.: A critical evaluation of present flood hazard maps in Southwest Germany using epigraphic marks and historical written data, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-586, https://doi.org/10.5194/egusphere-egu2020-586, 2019

D3679 |
EGU2020-5087<span style="font-size: .8em!important; font-weight: bold; vertical-align: super; color: green!important;"></span>
Conor Murphy, Robert Wilby, Tom Matthews, Csaba Horvath, Arlene Crampsie, Francis Ludlow, Simon Noone, Jordan Brannigan, Jamie Hannaford, Robert MacLeman, and Eva Jobbova

Historical precipitation records are fundamental for the management of water resources, yet rainfall observations typically span 100 – 150 years at most, with considerable uncertainties surrounding earlier records. Here, we analyse some of the longest available precipitation records globally, for England and Wales, Scotland and Ireland. To assess the credibility of these records and extend them further back in time, we statistically reconstruct (using independent predictors) monthly precipitation series representing these regions for the period 1748-2000. By applying the Standardised Precipitation Index at 12-month accumulations (SPI-12) to the observed and our reconstructed series we re-evaluate historical meteorological droughts. We find strong agreement between observed and reconstructed drought chronologies in post-1870 records, but divergence in earlier series due to biases in early precipitation observations. Hence, the 1800s decade was less drought prone in our reconstructions relative to observations. Overall, the drought of 1834-1836 was the most intense SPI-12 event in our reconstruction for England and Wales. Newspaper accounts and documentary sources confirm the extent of impacts across England in particular. We also identify a major, ‘forgotten’ drought in 1765-1768 that affected the British-Irish Isles. This was the most intense event in our reconstructions for Ireland and Scotland, and ranks first for accumulated deficits across all three regional series. Moreover, the 1765-1768 event was also the most extreme multi-year drought across all regional series when considering 36-month accumulations (SPI-36). Newspaper and other sources confirm the occurrence and major socio-economic impact of this drought, such as major rivers like the Shannon being fordable by foot. Our results provide new insights into historical droughts across the British Irish Isles. Given the importance of historical droughts for stress-testing the resilience of water resources, drought plans and supply systems, the forgotten drought of 1765-1768 offers perhaps the most extreme benchmark scenario in more than 250-years.

How to cite: Murphy, C., Wilby, R., Matthews, T., Horvath, C., Crampsie, A., Ludlow, F., Noone, S., Brannigan, J., Hannaford, J., MacLeman, R., and Jobbova, E.: The forgotten drought of 1765-1768: Reconstructing and re-evaluating historical droughts in the British and Irish Isles, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-5087, https://doi.org/10.5194/egusphere-egu2020-5087, 2020

D3680 |
EGU2020-8058<span style="font-size: .8em!important; font-weight: bold; vertical-align: super; color: green!important;"></span>
Fernando Domínguez-Castro, María Cruz Gallego, José M. Vaquero, Ricardo García Herrera, and Sergio M. Vicente-Serrano

The weather diary of Felipe de Zúñiga y Ontiveros (FZO) (Oaxtepec, 1717–Mexico City, 1793) provides daily meteorological information for rain frequency, temperature, frost, hail, thunderstorms, and windy days, from January 1775 to December 1786. It is the earliest obser­vational data collection with daily resolution retrieved in the region so far and it has higher time resolution than any other climate proxy available for this period. Some of the meteorological information provided by FZO could be compared with current meteorological records i.e. frequency of rain, hail, and thunderstorm. The seasonal distribution of these variables corresponds well during the FZO period and the present climate. 1781 was the warmest year in the FZO record while 1785 and 1778 were the coldest. FZO also identified a wet period (1782/1783) and two dry periods (1780/1781 and 1785/1786). The later coincides with the hunger year. It is considered the worst famine in Mexico during the colonial period (1521–1821).  A combination of adverse climate, lack of food, and an outbreak of typhus epidemic killed around 300,000 people. During these years a drought event extended over almost all the Mexican territory and was particularly severe over the central and northeastern regions. During the period 1785/86 FZO only recorded 188 rainy days. A similar record of low rainy days only occurred two times in the instrumental period: i) 1909/10 (188 days) and ii) 2010/11 (189 days). Both episodes with harmful consequences to the country e.g. water shortages, important loses in agriculture, farming, and forest fires. However, the climate during the hunger year was worse than during the instrumental droughts due to the high frequency of early killing frost. During 1785, frost events happened on April, August and September. FZO describes the impact of the frost and the attempt of the government to alleviate the famine “the frosts since August 28th have been so general that the fruits have been lost throughout the Kingdom, with the excep­tion of the warm lands; the government has asked them to sow corn, beans and other seeds in the irri­gated lands immediately so that they can be harvested by March 1786 and partially remedy the hunger that threatens”. Nevertheless, this decision was no useful because 1786 was driest than the 1785 impeding the growing of any crop. The annual summary of FZO for 1786 was, “It has been an unfortunate year due to scarcity of rain, supplies and everything needed for life, also in misfortune and public diseases”. The FZO´s diary is a good example of a documentary source that allows understanding the climate situation and the socio-economic response in detail during an extreme event.

How to cite: Domínguez-Castro, F., Gallego, M. C., Vaquero, J. M., García Herrera, R., and Vicente-Serrano, S. M.: The weather diary of Felipe de Zúñiga (1775-1786): A key documentary source to understand the hunger year in Mexico, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-8058, https://doi.org/10.5194/egusphere-egu2020-8058, 2020

D3681 |
EGU2020-9647<span style="font-size: .8em!important; font-weight: bold; vertical-align: super; color: green!important;"><span title="Early career scientist: an ECS is an undergraduate or postgraduate (Masters/PhD) student or a scientist who has received their highest degree (BSc, MSc, or PhD) within the past seven years. Provided parental leave fell into that period, up to one year of parental leave time may be added per child, where appropriate.">ECS</span></span>
Javier Mellado-Cano, David Barriopedro, Ricardo García-Herrera, Ricardo Trigo, and Armand Hernández

Instrumental records of the leading patterns of variability are short, hampering a proper characterization of the atmospheric circulation beyond the mid-19th century. In this work, recently published in Mellado-Cano et al. (2019), we present the longest (1685-2014) observational-based records of winter NAO and East Atlantic (EA) indices as well as estimates of the North Atlantic eddy-driven jet stream for the same period. They are inferred from wind direction observations over the English Channel assembled in monthly indices of the persistence of the wind in the four cardinal directions. Our NAO and EA series are significantly correlated with traditional indices, showing comparable skill to that obtained between some instrumental indices, and capture their main signatures on European temperature and precipitation.

By identifying winters with different combinations of NAO/EA phases in the 20th century, our results highlight the additional role of EA in shaping the North Atlantic action centers and the European climate responses to NAO. The joint effects of NAO and EA cause European surface climate anomalies that can substantially differ from their canonical signatures, meaning that a proper characterization of regional climates cannot be achieved by the NAO alone. The EA interference with the NAO signal is stronger in precipitation than in temperature and affects areas with strong responses to NAO such as Greenland and the western Mediterranean.

The time series display large variability from interannual to multidecadal time scales, with e.g. positive (negative) EA (NAO) phases dominating before 1750 (during much of the 19th century). The last three centuries uncover multidecadal periods characterized by specific NAO/EA states and substantial variability in the North Atlantic jet stream, thus providing new evidences of the dynamics behind some outstanding periods. Transitions in the NAO/EA phase space have been recurrent and pin down long-lasting anomalies, such as the displacement of the North Atlantic action centers in the late 20th century, besides some disagreements between historical NAO indices.

Mellado-Cano, J., D. Barriopedro, R. García-Herrera, R.M. Trigo, 2019: Examining the North Atlantic Oscillation, East Atlantic pattern and jet variability since 1685. Journal of Climate. doi: https://doi.org/10.1175/JCLI-D-19-0135.1

How to cite: Mellado-Cano, J., Barriopedro, D., García-Herrera, R., Trigo, R., and Hernández, A.: North Atlantic Oscillation, East Atlantic pattern and jet variability since 1685, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-9647, https://doi.org/10.5194/egusphere-egu2020-9647, 2020

D3682 |
EGU2020-11506<span style="font-size: .8em!important; font-weight: bold; vertical-align: super; color: green!important;"></span>
Kathleen Pribyl

This paper studies the occurrence and impacts of spring-summer droughts in pre-industrial England from 1200 to 1700. The study is based on documentary data, and the types of records and source availability are described, and an overview of droughts in those 500 years is provided. The focus lies on identifying the meteorological, hydrological and agricultural aspects of late medieval and early modern droughts, and on highlighting the structural impacts on the agricultural and pastoral economy, transport, energy supply and health. Due to the specific characteristics of wheat cultivation in medieval and early modern England, the grain production was comparatively resilient to drought. However, livestock farming was under threat, when rainfall levels fell noticeably below average. The most important problem in warm and dry summers was the risk to health. Partly steeply raised mortality levels were associated with these conditions during the study period, because malaria, gastrointestinal disease and plague showed an affinity to heat and drought. Adaptation strategies adopted by the people of pre-industrial England to reduce the stress posed by summer droughts will be discussed.

How to cite: Pribyl, K.: The impacts of spring-summer droughts in England, 1200-1700, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-11506, https://doi.org/10.5194/egusphere-egu2020-11506, 2020

D3683 |
EGU2020-14388<span style="font-size: .8em!important; font-weight: bold; vertical-align: super; color: green!important;"></span>
Kuan-Hui Elaine Lin, Pao K. Wang, Pi-Ling Pai, and Yu-Shiuan Lin

This study presents a new epistemology to analyze drought chronology through a clear-cut methodology for reconstructing past drought series as well as series for other associated ecological and societal variables. Instead of building grading system based on mixed criteria, this method can facilitate transparency in the reconstruction process and can enable statistical examinations of all variables when building the series. The data used is from the REACHES database, however other archival documentary and index data from independent sources are also applied to understand drought narratives and to cross check and validate the analysis derived from the REACHES. From time series analysis, six severe drought periods are identified in the Qing dynasty, and then spatial analysis is performed to demonstrate spatial distribution of drought and other variables in the six periods as well as social network analysis to reveal connections between drought and other ecological and societal variables. Research results clearly illustrate the role of human intervention to influence the impacts of drought on societal consequences. Particularly, the correlation between drought and socioeconomic is not strong; crop failure and famine are important intermediate factors, meanwhile ecological factor such as locust and disaster relief measures are all imperative to intervene between crop production and famine. Implications of the study on drought impact are provided as well as the significance of historical climate reconstruction studies.

How to cite: Lin, K.-H. E., Wang, P. K., Pai, P.-L., and Lin, Y.-S.: Historical droughts in the Qing dynasty (1644-1911) of China and the role of human interventions, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-14388, https://doi.org/10.5194/egusphere-egu2020-14388, 2020

D3684 |
EGU2020-17417<span style="font-size: .8em!important; font-weight: bold; vertical-align: super; color: green!important;"></span>
Rhonda McGovern, Conor Kostick, Laura Farrelly, and Francis Ludlow

Ancient Babylonia is a kingdom / province in the Fertile Crescent in south-central Mesopotamia (modern day Iraq). It has a rich textual and archaeological history and is the origin of many scientific and cultural advances, such as the definition of the seven-day week, the invention of zero, and many legal principles still underlying modern contract, tort, criminal, property, and family law.

The Irish Research Council-funded “Climates of Conflict in Ancient Babylonia” (CLICAB) project aims to investigate climatic changes in Babylonia during the final eight centuries BCE and assess for linkages to patterns of violence and conflict, through the application of methods from historical climatology to the wealth of data available. Although there are gaps in the recorded observations, and potentially more tablets yet to be found and translated, the 209 precisely dated, transliterated and translated tablets presently available will provide for many years a sub-daily window into the weather, and therefore the climate of this key historical region. This is a far greater resolution than is currently available for any region or period in the Ancient world, and indeed unprecedented in the world of historical climatology before the Early Modern Period.

Key to the project’s broader aims is the reconstruction of the climate for the region based on the information held in the Babylonian Astronomical Diaries. This paper thus examines the process of mining information from the detailed record maintained by Ancient Babylonian scribes in the Astronomical Diaries and presents an overview of the findings. These diaries are a collection of cuneiform tablets spanning 652-61BC, housed in the British Museum. They are rich in systematic weather observations (even down to an hourly resolution), astronomical phenomena, price data, and river heights for the Euphrates. Much work has been undertaken to examine the economic, astronomical and fluvial data, but until now the weather observations have remained relatively untouched, despite their unparalleled temporal resolution for this period, the systematic methodology applied in their recording, and the sheer breadth of information provided. This ranges from wind direction and intensity, to the level of cloud cover and references to atmospheric clarity (clear vs. dusty skies), to the general conditions (temperature and precipitation), for all seasons. This project will see the reconstruction of the climate for the region of Babylonia, and therefore provide one of the oldest weather records in the world. This paper presents high-resolution weather data from the Astronomical Diaries. Specifically, the authors will present the frequency of meteorological extremes over the period, alongside a discussion into the mitigation methods the Babylonians employed to reduce their vulnerability to these extremes. 

KEYWORDS: Ancient Babylonia, Climate, Conflict

How to cite: McGovern, R., Kostick, C., Farrelly, L., and Ludlow, F.: Reconstructing the climate of Ancient Babylonia, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-17417, https://doi.org/10.5194/egusphere-egu2020-17417, 2020

D3685 |
EGU2020-12300<span style="font-size: .8em!important; font-weight: bold; vertical-align: super; color: green!important;"></span>
Mika Ichino, Kooiti Masuda, Takehiko Mikami, and Yasuo Takatsuki

Japan has plenty of diaries in the 17th to 19th centuries, which include records of daily weather conditions ("fine", "cloudy", "rainy", etc.) It is well known that they have been used for reconstructing climate variation and events, although it provided qualitative data, not instrumental observations.

We estimate global solar radiation from weather conditions. Global solar radiation is an important factor for the energy balance of the Earth, and is also fundamental to the hydrological cycle and agricultural productivity. Our method is effective for all seasons and which could produce reconstruction with higher temporal resolution than other proxy data, for example tree rings.

Weather descriptions are classified into 3 categories and weather categories convert to solar radiation. The parameters of conversion are calculated by using JMA observations from 1995 to 1999.

We reconstructed monthly mean global solar radiation from 1821 to 1850 based on the weather records described in 11 historical diary documents. We focused on the years of Tempo Famine from 1833 to 1839.

In 1836, monthly solar radiation in summer in the east-west zone of Japan including Kanto, Kinki, and northern Kyushu was smaller than the provisional normal (average of 1821-1850). It was 10% or more smaller than the normal in July and August. However, it was not particularly small in Tohoku to the north of the zone and in southern Kyushu to the south of the zone. The characteristic of reconstruction in 1836 is that lower solar radiation prolonged from May to September in the central area of Japan. This suggests that climatic condition similar to Baiu was prolonged, and that it was cold in Tohoku. On the other hand, in 1833 and 1838, when famines also occurred, the reconstructed solar radiation was low in Tohoku.

We also checked the effect on market economy by observing the daily price of rice, the main crop at that time. For 1836, we can observe the sharp rise of the price in July. It suggests that the market had reacted to the bad climate condition before the harvest season. After this sharp rise, four times higher than usual, rice price reached a plateau then fell in September 1837.

While the rice price in 1833 and 1838 also rose up in summer, they were only two or three times higher than usual and, more importantly, they quickly bounced back.

Cross check between the reconstructed solar radiation and the rice price data support thus enables us to conclude that there existed a big difference even among the years recorded as “famine years” on the historical documents.

How to cite: Ichino, M., Masuda, K., Mikami, T., and Takatsuki, Y.: Reconstruction of solar radiation based on historical weather records in Japan - Climatic condition and market economy in the famine of 1830s -, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-12300, https://doi.org/10.5194/egusphere-egu2020-12300, 2020

D3686 |
EGU2020-22271<span style="font-size: .8em!important; font-weight: bold; vertical-align: super; color: green!important;"></span>
Özlem Sert

Humid weather conditions of the sixteenth century enabled the introduction of aqua crops to Southeastern European landscapes. The Ottoman government employed a group of experts for the cultivation of rice to implement and rehabilitate rice production. Rice plantations, as an anthropogenic intrusion in the region between Tigris to the Danube, had a fundamental social and environmental impact. Organization of human resources on a large scale; land reclamations, deforestation, and kilometres-long irrigation work changed the landscape, produced seasonal miasma and aquatic pests. Ottoman rice plantations transformed the Southeastern European socio-ecological landscapes in early modern times. Historical data about the Ottoman rice plantations open new insights for improving our knowledge about climate history, the history of riverbeds and the history of malaria in this landscape. The study presents a monography of the plantations with historical drawings and maps, showing the farms on river beds, delineates the responsiveness of the rice harvest to precipitation and temperature changes and maps the triggered aquatic pests due to climate change and deforestation. The presentation aims at opening a historical perspective to today's questions on climate change, hydrology and vector caused diseases.

How to cite: Sert, Ö.: Effects of Ottoman Rice Plantations in South-eastern European Landscape: Climate Change, Hydrology and Disease, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-22271, https://doi.org/10.5194/egusphere-egu2020-22271, 2020

D3687 |
EGU2020-648<span style="font-size: .8em!important; font-weight: bold; vertical-align: super; color: green!important;"><span title="Early career scientist: an ECS is an undergraduate or postgraduate (Masters/PhD) student or a scientist who has received their highest degree (BSc, MSc, or PhD) within the past seven years. Provided parental leave fell into that period, up to one year of parental leave time may be added per child, where appropriate.">ECS</span></span>
Gheorghe Badaluta, Carmen - Andreea Badaluta, Monica Ionita, and Marcel Mindrescu

Floods are among the most destructive natural hazards which affect socio-economical systems. Flood occurrence is considered to be a sensitive indicator of climate variability and is related in particular with changes in atmospheric circulation modes. One of the best archive of the floods evidence are historical documents. In this study we present 1000 years of floods reconstruction, which are some of the most frequent and well documented hazards in lowland areas of Romania. Our investigation spans over three distinct periods: the Medieval Warm Period (MWP), the Little Ice Age (LIA) and the Modern Period (MD), respectively, and it’s the longest one, on record, over this area. In total, we extracted 191 flood events which occurred in 167 years. Of 191 flood events, 16 occurred in winter, 34 in spring, 76 in summer, 18 in autumn, whereas for 47 flood events the season was not specified. The results show three periods of increasing floods activity during the Late Medieval Warm Period, middle part of LIA (between AD 1550-1750) and the entire Modern Period. A small increase in the number of flood events was observed during the MWP with an occurrence rate slightly higher than 0.15/year. The highest flood occurrence rates have been documented during LIA (i.e. 16th and 17th centuries) with an increasing trend of up to ~ 0.4/year. The majority of these events were recorded in summer and were typically generated by heavy thunderstorms. Moreover, the rising temperatures of MD were reflected in the increasing flood occurrence rates of up to 0.39/year. In conclusion, our 1000-year long reconstruction of past flood events could bring a major contribution to the knowledge of hydro-meteorological events of Central Eastern Europe and may be used as an indicator for assessment of floods hazards and for predicting the influence in future, in the context of ongoing climatic changes.

How to cite: Badaluta, G., Badaluta, C.-A., Ionita, M., and Mindrescu, M.: Documentary evidence of historical floods in lowland Romania during the last millennium, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-648, https://doi.org/10.5194/egusphere-egu2020-648, 2019

D3688 |
EGU2020-5133<span style="font-size: .8em!important; font-weight: bold; vertical-align: super; color: green!important;"></span>
Kateřina Chromá, Rudolf Brázdil, Lukáš Dolák, Jan Řehoř, and Ladislava Řezníčková

Reports from the newspaper “Rudé právo/Právo”, complemented by chronicles, epigraphic evidence, systematic meteorological/hydrological observations, media (including internet), professional reports and papers were used to create a database of fatalities taking place in the course of hydrological and meteorological events over the territory of the Czech Republic during the 1964–2019 period. The spatiotemporal variability of fatalities arising out of floods, flash floods, windstorms, convective storms, lightning, frosts, snow/glaze-ice calamities, avalanches, heats and other events is shown, with particular attention to closer characterisation of fatalities (gender, age, cause of death, place, type of death and behaviour). In the classification of fatalities, males and adults clearly prevail, while indirect victims and hazardous behaviour are strongly represented. Examples of two outstanding events with the highest numbers of fatalities during a flash flood on 9 June 1970 (34 fatalities) and a rain-induced flood in July 1997 (60 fatalities) are described in detail. Discussion of results includes the problem of data uncertainty, factors influencing the numbers of fatalities, and the broader context. The study emphasises the significance of documentary data and reveals its new utilisation in the study of fatalities in the Czech Republic.

How to cite: Chromá, K., Brázdil, R., Dolák, L., Řehoř, J., and Řezníčková, L.: Documentary data in the study of fatalities caused by meteorological and hydrological events: the Czech Republic, 1964–2019, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-5133, https://doi.org/10.5194/egusphere-egu2020-5133, 2020

D3689 |
EGU2020-5149<span style="font-size: .8em!important; font-weight: bold; vertical-align: super; color: green!important;"></span>
José Manuel Vaquero, María Cruz Gallego, Víctor M. S. Carrasco, Nieves Bravo-Paredes, María Ángeles Obregón, and Carlos Lara

Our efforts to a better understanding of the historical climate of the region of Extremadura (interior of the SW Iberia) have been directed in two main aspects. First, we have tried to recover all the meteorological data of the pre-instrumental period. Second, we have been working on the localization and analysis of proxy data, including “pro-pluvia” rogation ceremonies and a chronology of catastrophic floods in this region.

The recovery of historical meteorological data from libraries and archives and the subsequent digitization to obtain readable-machine version has been a main task in our research. Meteorological data from different sources (manuscripts, books, newspapers, etc.) and eight different locations in Extremadura have been recovered and digitized. The oldest data were read in 1824 (Fernández-Fernández et al., 2014). Other important meteorological series can be highlighted as the actinometric measurements in Cáceres for the period 1913-1920 (Bravo-Paredes et al., 2019).

“Pro-pluvia” rogations were celebrated during dry conditions to ask God for rain. In our case, 35 “pro-pluvia” rogations were retrieved for the period 1824-1931 from different locations in Extremadura. The winter climate of this region is strongly dominated by the North Atlantic Oscillation (NAO) and, therefore, these pro-pluvia rogations were associated to the NAO index to analyze this relationship. The results of our analysis show that the rogation ceremonies in Extremadura can be considered a good proxy for the NAO index. Also, it is important to know the magnitude and the impact of the catastrophic floods occurred in Extremadura. In total, 40 floods occurred in Badajoz were recovered from different documentary sources for the period 1545-1989.

All these research efforts will allow for a better understanding of the past climate in the region of Extremadura, where such studies have been very scarce.

References

Bravo-Paredes, N. et al. (2019) “Analysis of actinometric measurements under different sky conditions in Cáceres (Spain) for the period 1913-1920” Tellus B 71, 1663597. DOI: 10.1080/16000889.2019.1663597

Fernández-Fernández, M.I. et al. (2014) "The climate of Zafra from 1750 to 1840: History and description of weather observations" Climatic Change 126, 107–118. (doi: 10.1007/s10584-014-1201-5)

How to cite: Vaquero, J. M., Gallego, M. C., Carrasco, V. M. S., Bravo-Paredes, N., Obregón, M. Á., and Lara, C.: Towards a better assessment of the historical climate of Extremadura region (SW Spain), EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-5149, https://doi.org/10.5194/egusphere-egu2020-5149, 2020

D3690 |
EGU2020-5350<span style="font-size: .8em!important; font-weight: bold; vertical-align: super; color: green!important;"></span>
Ranjini Ray and Atreyee Bhattacharya

Climate disasters such as droughts and floods are becoming very important in 21st century India especially in the semi-arid tracts of rain-shadow regions of peninsular India – stretching from Maharashtra in the west to Tamil Nadu in the south. The role of climate variability in these climate disasters and the climate forcings working behind these needs a special attention. Here we present new data, pertaining to climate disasters, impacts and adaptive strategies, from a review of 60 volumes of archival institutional documents from the British Colonial Period pertaining to administration of districts of peninsular India. The documents span ~ 220 years (1729-1947 AD) and encompass the two phases of the British colonial period, the Company period (before 1858) and the Crown period (1858-1947) respectively. We found archival institutional documents to be excellent archives for reconstructing a chronology of climate disasters, studying the effects of these disasters and assessing the efficacy of adaptive strategies and policies at local scales, often at the level of districts (<30 kms). Vivid accounts describe impacts of climate disasters e.g crop failure, price hike, farmer migration, riot, starvation, epidemic diseases, death during droughts, and colossal destruction, migration and death due to heavy rainfall (and associated floods). Farmers being the most affected group. In 19th century famines due to droughts continued to occur every 5-10 years if the rainfall fell below 14% of the average annual rainfall, consistent with decadal and sub-decadal modes of rainfall variability. This data is comparable with the tree ring data found in this area. Climate variability is to some extent at par with ENSO events but land atmosphere interaction especially due to anthropogenic activities such as deforestation can be a major climate forcing that acted in this area. During the Crown period protective measures were very similar even though governance changed. But British government had to change their policies when sudden huge fall in rainfall occurred in 1876 and 1899 causing major famines (Great Famine 1876-1877, Indian Famine1899-1900). Formation of Famine Codes and Famine Commissions (1880-1901) after these two major famines made situation better, changes were done in grass root level. We see no major famine caused by droughts in peninsular India after that.

How to cite: Ray, R. and Bhattacharya, A.: Assessing the impacts of climate variability - a study of institutional archival data spanning 1700-1947 (British Colonial Period) pertaining to semi-arid tracts of peninsular India, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-5350, https://doi.org/10.5194/egusphere-egu2020-5350, 2020

D3691 |
EGU2020-6740<span style="font-size: .8em!important; font-weight: bold; vertical-align: super; color: green!important;"><span title="Early career scientist: an ECS is an undergraduate or postgraduate (Masters/PhD) student or a scientist who has received their highest degree (BSc, MSc, or PhD) within the past seven years. Provided parental leave fell into that period, up to one year of parental leave time may be added per child, where appropriate.">ECS</span></span>
Thomas Pliemon, Ulrich Foelsche, Christian Rohr, and Christian Pfister

Based on copies of the original data (source: Oeschger Center for Climate Change Research) we perform climate reconstructions for Paris. The focus lies on the following meteorological variables: temperature, cloudiness, moving direction of clouds and precipitation. We assess the early instrumental temperature dataset with state of the art statistical methods to get further knowledge of inhomogeneities. There are already several studies showing monthly and yearly means of the temperature, but a detailed statistical analysis based on the original measurements has not been done yet. Due to the lack of metadata, we do a qualitative analysis. With rare contemporary time series, like the CET (Central England Temperature), and proxydata, like grape harvest dates, we attempt to make a quantitative statement. We analyse and discuss the documentary datasets of the cloudiness and the moving direction of the clouds relating to the cooling in the Late Maunder Minimum. Because of the subjective character of documentary records, we compare these results with available data from former publications. Precipitation is given in terms of intensity and duration. We calculate indices like rainfall frequency and average rainfall per year/season/month.

How to cite: Pliemon, T., Foelsche, U., Rohr, C., and Pfister, C.: Analysis of Subdaily Meteorological Measurements by Louis Morin in the Late Maunder Minimum 1665 – 1713 in Paris, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-6740, https://doi.org/10.5194/egusphere-egu2020-6740, 2020

D3692 |
EGU2020-6803<span style="font-size: .8em!important; font-weight: bold; vertical-align: super; color: green!important;"></span>
Lukáš Dolák, Rudolf Brázdil, Petr Dobrovolný, Hubert Valášek, Ladislava Řezníčková, Kateřina Chromá, and Oldřich Kotyza

To develop an understanding of recent variability in strong winds, it is necessary to analyse their past behaviour. While relatively short series of wind-speed measurement in the Czech Lands (recent Czech Republic) started mostly in the first half of the 20th century, documentary evidence represents a valuable source of information helping extend the knowledge of strong winds to the pre-instrumental period. In this study, we analyse strong winds on the basis of chronicles, weather diaries, early journalism, economic and financial sources, as well as old academic journals, newspapers, professional papers and recent scientific papers. The created dataset presents a chronology of strong winds in the Czech Lands from AD 1510 to present. The dataset contains more than 5000 events, which are classified on duration, location, extent, severity and type of damage on squalls (convective storms), tornadoes, blizzards, gales and windstorms. Gales, often accompanied by loss of human lives, damage to buildings and forests (windthrows), are the most frequently recorded type of strong winds (44%), followed by blizzards (26%), squalls (18%), and tornadoes (7%). Strong winds detected are concentrated 1820s to late-1840s, 1900s to late-1930s and in the 2000s. Seasonal distribution of strong winds is relatively equal throughout the chronology with the highest frequency in July (10.0%), January (8.6%), and December (8.1%). Uncertainties in results emerge from a different spatiotemporal density of documentary data and from the ambiguous nature of some records in determining the classification of strong winds or attribution of damage caused to particular events. Our results highlight the importance of documentary evidence in the analysis of strong winds and contribute to a better understanding of their spatiotemporal variability in the past.

How to cite: Dolák, L., Brázdil, R., Dobrovolný, P., Valášek, H., Řezníčková, L., Chromá, K., and Kotyza, O.: Chronology of strong winds based on documentary evidence in the Czech Republic from AD 1510, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-6803, https://doi.org/10.5194/egusphere-egu2020-6803, 2020

D3693 |
EGU2020-10147<span style="font-size: .8em!important; font-weight: bold; vertical-align: super; color: green!important;"></span>
Andrea Kiss, Mariano Barriendos, Rudolf Brázdil, Chantal Camenisch, Silvia Enzi, Piotr Olinski, Kathleen Pribyl, and Dag Retsö

In the 1500s-1510s an unusually high number of significant droughts in Central and Western, and partly in Southern Europe; the years 1502-1504, 1506-1507, 1513-1514 and 1516-1518 were dry particularly in Central and Western Europe. Droughts, interspersed with wet years marked even by significant floods and other weather-related extremes, and frequent hard winters were mainly responsible for the reduced or poor crop and hay harvests in multiple years. These circumstances, in combination with other socio-economic factors, contributed to the increased social tension of the period, manifesting itself in major peasant uprisings, and might have acted as a catalyst in the timing and rapid spread of the Reformation.

The first part of the presentation is concentrated on the reconstruction and spatial-temporal analysis of the droughts (and hard winters) using documentary evidence – in comparison with the tree-ring based hydroclimate reconstruction (OWDA: Cook et al. 2015) and the multiproxy-based reconstruction of Central European precipitation (Pauling et al. 2006).

The most significant groups of socio-economic consequences are analysed in the second part of the presentation, with special emphasis on discussing the possible cumulative effects of the anomalous weather conditions during the period on the ongoing transformation of the late-medieval society and economy and the Reformation itself.

How to cite: Kiss, A., Barriendos, M., Brázdil, R., Camenisch, C., Enzi, S., Olinski, P., Pribyl, K., and Retsö, D.: Climate of the Reformation: droughts and anomalous weather in the 1500s-1510s in Europe, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-10147, https://doi.org/10.5194/egusphere-egu2020-10147, 2020

D3694 |
EGU2020-17698<span style="font-size: .8em!important; font-weight: bold; vertical-align: super; color: green!important;"><span title="Early career scientist: an ECS is an undergraduate or postgraduate (Masters/PhD) student or a scientist who has received their highest degree (BSc, MSc, or PhD) within the past seven years. Provided parental leave fell into that period, up to one year of parental leave time may be added per child, where appropriate.">ECS</span></span>
Dmytro Boichuk, Jürg Luterbacher, Rob Allan, Olesya Skrynyk, Vladyslav Sidenko, Angelika Palarz, Dmytro Oshurok, Elena Xoplaki, Oleg Skrynyk, and Volodymyr Osadchyi

Modern climate applications and climate services are seeing the need for more data and information (including its historical part) on climate variability at high temporal and spatial resolution. Therefore, daily or even sub-daily meteorological data are required increasingly to feel this gap and provide the basis for climate research, extreme events analysis and impact studies.

The main objective of our work is to present information on results of data rescue (DARE) activity conducted recently in the Ukrainian Hydrometeorological Institute (UHMI, Kyiv, Ukraine) in close collaboration with several national and international partners. Our DARE activity was concentrated mainly on the original sub-daily, pre-1850 meteorological observations conducted at eight meteorological stations located in the territory of modern Ukraine, namely Kyiv, Kharkiv, Poltava, Kamyanets-Podilsky, Lugansk, Dnipro, Kherson and Odesa. These eight stations are the only ones, whose pre-1850 data have been found in an archive of the Central Geophysical Observatory (CGO), an observation institution of the Ukrainian Weather Service.

The data are contained in 38 special hard copy books. Before digitization, the book pages were photocopied to create a database of the images of all the paper sources. Its two copy versions are now stored at the UHMI and CGO, respectively. After the creation of the images database, the data were digitized manually by the authors. In total 291 103 values were digitized. These include 165 980 air temperature records (~57% of the total), 124 376 atmospheric pressure measurements (~42.7%) and 747 precipitation totals (~0.3%).

Quality control of the digitized data was conducted, including intercomparisons between the stations as well as comparisons with monthly temperature data that were digitized previously from other sources. The quality control procedures revealed a fairly good agreement among the rescued time series on the monthly time scale as well as a good accordance with the monthly data from other sources. However, several periods at some stations should be used with caution, due to relatively large discrepancies revealed. The rescued digital dataset can be used for different meteorological and climatological purposes, including the analysis of extreme events for the pre-1850 period in comparison with today’s climate, regional climatological studies, etc. The dataset is an important supplement to existing digitized archives of meteorological measurements that were performed in the first half of the 19th century.

How to cite: Boichuk, D., Luterbacher, J., Allan, R., Skrynyk, O., Sidenko, V., Palarz, A., Oshurok, D., Xoplaki, E., Skrynyk, O., and Osadchyi, V.: Rescue of Ukrainian early historical climatological data, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-17698, https://doi.org/10.5194/egusphere-egu2020-17698, 2020

D3695 |
EGU2020-19767<span style="font-size: .8em!important; font-weight: bold; vertical-align: super; color: green!important;"></span>
Eric Gaume, Maryse Charpentier-Noyer, and Olivier Payrastre

One of the most impressive flash floods of the last century in France, as in Spain, occurred in the Eastern part of the Pyrenees on the 17th and 18th of October 1940. 47 people died in France during this extraordinary event and more than 100 in Catalunia. This flood caused considerable damages to buildings and, in particular, destroyed the center of the thermal town of Vernet-les-Bains on the slopes of the mount Canigou. The maximum observed 24-hour rainfall amount was close to one meter and remains until now one of the French record values. This flooding has already been widely documented both by the state technical services and by scientists of the time. Much of this documentation, which has been archived and is still available, makes it possible to propose new evaluations in the light of the recent advancements in flash floods studies. The conclusions of this work of flood reanalysis are presented, and are supplemented here by hydraulic simulations in order to test different hypotheses concerning the timing and magnitude (i.e. discharge values) of the flood. The Basilisk software (finite volume method for shallow water equations with adaptive mesh refinement) is used to conduct the 2D-hydraulic simulations. The initial reanalysis of the flood revealed that (1) the peak discharge values estimated in 1940, on which local risk assessment studies are based, had probably been largely over-estimated; (2) a sudden increase of local water levels, described by eye-witnesses in the town of Elne, was due to the breach of a railway embankment in the floodplain upstream the town. The hydraulic simulations, carried out both with the peak discharge estimated in 1940 and with the re-evaluated one, show that the former values are not compatible with the flood witnesses’ accounts - which retrace the chronology of the episode - or with the surveyed water levels. The revised and reduced peak discharge appears to be more realistic according to the data retracing the event. Moreover, the presence of the breach in the railway line embankment appears to explain the maximum water levels observed in the town of Elne. This work illustrates that major past-flood events may be re-interpreted at the light of our increased scientific knowledge provided that they have been well documented at the time of their occurrence, which is often the case for major devastating floods.

How to cite: Gaume, E., Charpentier-Noyer, M., and Payrastre, O.: The October 1940 extreme flood in the Pyrenees revisited: validation of some hypotheses based on hydraulic simulations, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-19767, https://doi.org/10.5194/egusphere-egu2020-19767, 2020

D3696 |
EGU2020-613<span style="font-size: .8em!important; font-weight: bold; vertical-align: super; color: green!important;"><span title="Early career scientist: an ECS is an undergraduate or postgraduate (Masters/PhD) student or a scientist who has received their highest degree (BSc, MSc, or PhD) within the past seven years. Provided parental leave fell into that period, up to one year of parental leave time may be added per child, where appropriate.">ECS</span></span>
A Quantitative Hydroclimatic Context for the European Great Famine of 1315-1317
(withdrawn)
Seung Hun Baek, Jason Smerdon, George-Costin Dobrin, Jacob Naimark, Edward Cook, Benjamin Cook, Richard Seager, and Mark Cane
D3697 |
EGU2020-6961<span style="font-size: .8em!important; font-weight: bold; vertical-align: super; color: green!important;"></span>
Julia Eulenstein and Andreas Kellerer-Pirklbauer

One of the most severe floods that has ever been registered in the catchment of the Upper Danube River in Central Europe is the one that took place in June/July 1572. This flood was caused by a prolonged precipitation event related to a so-called Vb cyclone. Such cyclones develop either over the Bay of Biscay or the Mediterranean (Genoa region), move eastward via Italy and the Adriatic Sea, and subsequently turn northeast. Vb cyclones bring extreme weather conditions with sustained precipitation over the northern side of the European Alps and Central Europe.

The impacts of the Vb cyclone in 1572 severely affected transport routes and local economies as indicated for instance by salt transport data from the Salzach River, one tributary stream (via the Inn River) of the Danube River. Different means of remembrance as historical flood level markers or memorial stones at several cities in Central Europe suggest that contemporaries considered the outcome of the cyclone as catastrophic. The modern quantification of the effects of such an extreme meteorological event helps to increase the understanding of the human-nature relationship in a period when manmade, modern changes of riverbeds and protection structures against floods or debris flows did not exist or did so only to a very limited extent. However, quantifying the effects of a historical regional-scale flood event in terms of degree of devastation at local-sale is normally outright impossible due to lack of detailed data.

In the Styrian Provincial Archive in Graz, Austria, a detailed damage inventory referring to the cyclone of 1572 exists. The purpose of the inventory was to reduce taxes for the Benedictine Abbey of Admont. The interdisciplinary analysis (historian, geographer) of the source enabled a local-scale insight into the effects of the cyclone at Admont. The inventory contains a list of 355 subjects of the abbey distributed over 12 administrative units that suffered minor to severe (complete destruction) damage related to flooding (main river or tributary creeks), debris-flows or landslides.

Further historical sources and geographical data such as land registers and cadastres allowed the localization of 150 damaged buildings at cadastral scale in the valley surrounding the abbey. Our analyses show that most of the properties were located near watercourses at alluvial fans or at slopes above the Enns valley bottom. A significantly greater amount of damage was revealed for properties, which would be nowadays located in moderate- and high-risk hazard zones (according to the Austrian Federal Service for Torrent and Avalanche Control). However, only 18.7% of the properties damaged in 1572 are located inside modern hazard zones. Modern hazard zone maps are commonly based on runoff modelling using design flood events. Our analysis suggests, nevertheless, that previously undetected or unconsidered sources might contribute substantially to the understanding of the spatial pattern of potential damage in an entire valley region during an exceptional cyclone at a local and even cadastre scale. This achievement is possible despite obvious changes in geomorphological, hydrographical, building structure and protective measure conditions since 1572. 

How to cite: Eulenstein, J. and Kellerer-Pirklbauer, A.: 448 years after the event: quantifying the local-scale effects of a Vb cyclone hitting Central Europe in 1572 using a detailed historical damage inventory, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-6961, https://doi.org/10.5194/egusphere-egu2020-6961, 2020

D3698 |
EGU2020-18752<span style="font-size: .8em!important; font-weight: bold; vertical-align: super; color: green!important;"></span>
Inês Amorim, Luís Sousa Silva, and João Carlos Garcia

Flood historical records are important to place current flooding events into a long-term perspective. With these data sets it is possible to identify patterns in past recent floods and use these to characterize and model future floods. In what concerns to Portugal, some studies had already used some documentary evidence in order to reconstruct flood events, in particular centered in the year 1786 that was the rainiest in Portugal, triggering floods in northwestern and central Portugal, followed by a extremely wet and rainfall 1788 year that caused floods along the largest Iberian rivers: Douro, Mondego and Tagus. However, very little is known about the characteristics of these events prior to the beginning of regular meteorological/hydrological observations (late 19th century in Portugal).

Within this framework, we aim to reconstruct a high-resolution history of floods occurred on the estuary of the Douro River (near the city of Porto, Portugal, Iberian’ Northwest) during the 19th century. The Douro River is the third-longest river in the Iberian Peninsula (after the Tagus and the Ebro rivers) and it drains an area of 97.600 square kilometers (the most largely in the Iberian Peninsula). To achieve our main aim, early instrumental observations and documentary evidence from multiple archival sources were collected. Further, the flooding archive was used to make a serial analysis of the years of floods, their chronological distribution, frequency, duration and intensity, associated with meteorological phenomena and their impacts.

How to cite: Amorim, I., Sousa Silva, L., and Garcia, J. C.: High-resolution reconstruction of extreme hydrological events occurred in the Douro River estuary (Portugal, Iberian Northwest) during the 19th century, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-18752, https://doi.org/10.5194/egusphere-egu2020-18752, 2020

D3699 |
EGU2020-17284<span style="font-size: .8em!important; font-weight: bold; vertical-align: super; color: green!important;"></span>
Martin Hanel, Sadaf Nasreen, Mijael Vargas, Ujjwal Singh, Petr Máca, Oldřich Rakovec, Rohini Kumar, and Yannis Markonis

In present paper we compare the reconstructed gridded seasonal precipitation (P) and temperature (T) for Europe [1,2] to the available station data from the GHCN [3,4] network going back to 1800. The basic statistical properties at various time-scales ranging from 1/4 to 30 years are examined. It is shown, that there are significant biases in the reconstructed P and T and the bias in mean and variability considerably vary over the time-scales. The same applies for considered drought indices. We further investigate how the simulation of hydrological model driven by reconstructed data compares to that based on station data and runoff from GRDC database. In addition, a set of data-driven methods is used to link the reconstructed and observed P and T data to observed runoff, the results are validated and a reconstruction back to 1500 is provided. Finally, we check to what extent the raw proxy data can be used for drought reconstruction.

[1] https://doi.org/10.1007/s00382-005-0090-8
[2] https://doi.org/10.1126/science.1093877
[3] https://doi.org/10.1175/JCLI-D-18-0094.1
[4] doi:10.7289/V5X34VDR

How to cite: Hanel, M., Nasreen, S., Vargas, M., Singh, U., Máca, P., Rakovec, O., Kumar, R., and Markonis, Y.: Validation of reconstructed hydroclimate variables for past drought assessment, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-17284, https://doi.org/10.5194/egusphere-egu2020-17284, 2020

D3700 |
EGU2020-12820<span style="font-size: .8em!important; font-weight: bold; vertical-align: super; color: green!important;"></span>
Zhixin Hao

In China, historical documents record a large quantity of information related to climate change and grain harvest. This information can help to explore the impacts of extreme drought or flood on crop production, which can provide implications for the adaptation of agriculture to higher-probability extreme climate in the context of global warming. In this paper, reported extreme drought/flood chronologies and reconstructed grain harvest series derived from historical documents were adopted in order to investigate the association between the reported frequency of extreme drought/flood in eastern China and reconstructed poor harvests during 801–1910. The results show that extreme droughts were reported more often in 801–870, 1031–1230, 1481–1530, and 1581–1650 over the whole of eastern China. On a regional scale, extreme droughts were reported more often in 1031–1100, 1441–1490, 1601–1650, and 1831–1880 in the North China Plain, 801–870, 1031–1120, 1161–1220, and 1471–1530 in Jianghuai, and 991–1040, 1091–1150, 1171–1230, 1411–1470, and 1481–1530 in Jiangnan. The grain harvest was reconstructed to be generally poor in 801–940, 1251–1650, and 1841–1910, but the reconstructed harvests were bumper in 951–1250 and 1651–1840, approximately. During the entire period from 801 to 1910, the frequency of reporting of extreme droughts in any subregion of eastern China was significantly associated over the long term with lower reconstructed harvests. The association between reported frequency of extreme floods and reconstructed low harvests appeared to be much weaker, while reconstructed harvest was much worse when extreme drought and extreme flood in different subregions were reported in the same year. The association between reconstructed poor harvests and reported frequency of regional extreme droughts was weak during the warm epoch of 920–1300 but strong during the cold epoch of 1310–1880, which could imply that a warm climate could weaken the impact of extreme drought on poor harvests; yet other historical factors may also contribute to these different patterns extracted from the two datasets.

How to cite: Hao, Z.: Patterns in data of extreme droughts/floods and harvest grades derived from historical documents in eastern China during 801–1910, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-12820, https://doi.org/10.5194/egusphere-egu2020-12820, 2020

D3701 |
EGU2020-8394<span style="font-size: .8em!important; font-weight: bold; vertical-align: super; color: green!important;"></span>
Jean-Philippe Vidal, Alexandre Devers, Claire Lauvernet, Olivier Vannier, Laurie Caillouet, Eric Sauquet, and Benjamin Graff

The recently developed French hYdrometerological Reanalysis (FYRE) covers the period 1871-2012 and provide high-resolution ensemble reconstructions of both climate and hydrology over France. FYRE Climate combines a statistical downscaling of the global Twentieth Century reanalysis (Caillouet et al., 2019) with in-situ station observations through Ensemble Kalman filter (EnKF) data assimilation (Devers et al., 2020). FYRE Climate is composed of 25 members of daily temperature and precipitation fields on a 8~km grid over France. It served as forcings for a conceptual hydrological model over 661 near-natural catchments to build streamflow reconstructions spanning 142 years. These reconstructions have then been combined with historical streamflow observations, again through EnKF data assimilation, to build the FYRE Hydro 25-member daily hydrological reanalysis over the 661 catchments.

FYRE Hydro is here validated with various types of documentary evidence (poem, complaint letter, and photograph), focusing on extreme low-flow events and their spatial and temporal fingerprint. They serve as examples of naturally extreme hydrological events that are exacerbated through human interventions, the magnitude of which has yet to be consistently quantified over the course of the Anthropocene.

 

References

Caillouet, L., Vidal, J.-P., Sauquet, E., Graff, B., Soubeyroux, J.-M. (2019) SCOPE Climate: a 142-year daily high-resolution ensemble meteorological reconstruction dataset over France. Earth System Science Data, 11, 241-260. https://doi.org./10.5194/essd-11-241-2019

Devers, A., Vidal, J.-P., Lauvernet, C., Graff, B., Vannier, O. (2020) A framework for high-resolution meteorological surface reanalysis through offline data assimilation in an ensemble of downscaled reconstructions. Quarterly Journal of the Royal Meteorological Society. https://doi.org./10.1002/qj.3663

How to cite: Vidal, J.-P., Devers, A., Lauvernet, C., Vannier, O., Caillouet, L., Sauquet, E., and Graff, B.: Validating the French hYdrometeorological REanalysis (FYRE) with documentary evidence, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-8394, https://doi.org/10.5194/egusphere-egu2020-8394, 2020

D3702 |
EGU2020-6864<span style="font-size: .8em!important; font-weight: bold; vertical-align: super; color: green!important;"></span>
Rudolf Brázdil, Petr Dobrovolný, Andrea Kiss, Piotr Oliński, and Ladislava Řezníčková

The summers of 15311540 in the Czech Lands were, according to three drought indices (SPI, SPEI, Z-index) reconstructed from the Czech documentary evidence and instrumental records (Brázdil et al., Clim. Res., 2016), the driest decade during the past five centuries. Based on documentary data, dry patterns of different intensity (represented e.g. by dry spells, low number of precipitation days, drying rivers and lack of water sources, frequent fires) for central Europe (Germany, Switzerland, Austria, Czech Republic, Poland, Slovakia and Hungary) were well expressed for summers in 1532, 1534–1536, 1538 and particularly in 1540. Summer droughts derived from documentary data in central Europe were confronted with gridded summer precipitation totals reconstructed from instrumental, documentary and selected natural proxies (Pauling et al., Clim. Dyn., 2006) and further with summer scPDSI reconstructed from tree-ring widths in the Old World Drought Atlas – OWDA (Cook et al., Sci. Adv., 2015). While in precipitation reconstruction summers of 1531–1540 represented the driest decade of the past 500 years in central Europe, according to scPDSI from OWDA it was the ninth driest decade, despite quite important spatial differences in the occurrence of drier and wetter areas between both reconstructions. From the analysis it follows that particularly the summers of 1534, 1536, 1538 and 1540 were dry not only in central Europe, but also over greater parts of western Europe.

How to cite: Brázdil, R., Dobrovolný, P., Kiss, A., Oliński, P., and Řezníčková, L.: The summers of 1531–1540 in Central Europe: The driest decade of the past five centuries?, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-6864, https://doi.org/10.5194/egusphere-egu2020-6864, 2020