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Abstract Maritime historical documentary sources of weather and state of sea surface including sea ice can aid in filling a known climate knowledge gap for the Southern Ocean and Antarctica for the first half of the 20th century. This study presents a data set of marine climate, sea ice and icebergs recovered from a collection of logbooks from mainly Norwegian whaling factory ships that operated in the Southern Ocean during 1929–1940. The data set comprises some 8000 weather and 4000 sea ice/open sea records from austral summers of the study period. This paper further discusses the structure and content of most common Norwegian maritime documentary sources of the period along with the practices of logging information relevant for the study, such as time keeping, positioning and making weather observations. An emphasis was made on recovery of notes on sea ice and icebergs and their interpretation in terms of WMO categories of sea ice concentration. Data, including ship‐related metadata from all individual documents are homogenized and structured to a common machine‐readable format that simplifies its ingestion into relevant climate data depositories.

Abstract We describe the transcription and quality control processes for rescuing around 570,000 sub‐daily and daily weather observations which were recorded in the UK Met Office Daily Weather Reports during the 1861–1875 period. These data are from the start of coordinated weather observations and were collected with the aim of making the first‐ever weather forecasts. The observations were rescued thanks to 3500 volunteers and include sub‐daily sea‐level pressure, dry and wet bulb temperatures, daily maximum and minimum temperatures, and daily rainfall amounts from 70 different locations across Western Europe, and one in Canada. We highlight how these observations will be used to fill gaps in existing pressure and temperature datasets and use two case studies to show how the pressure observations will likely better constrain the atmospheric circulation during two severe storms. We also compare a sub‐sample of the newly rescued observations with data that were previously digitized for a small number of locations for the same dates, finding good agreement in general, although some discrepancies remain.

Abstract The majority of available climate data in global digital archives consist of data only from the 1940s or 1950s onwards, and many of these series have gaps and/or are available for only a subset of the variables which were actually observed. However, there exist billions of historical weather observations from the 1700s, 1800s, and early 1900s that are still in hard‐copy form and are at risk of being lost forever due to deterioration. An assessment of changes in climate extremes in several IPCC regions was not possible in IPCC AR6 WGI owing, in many cases, to the lack of available data. One such region is Africa, where the climate impact research and the ability to predict climate change impacts are hindered by the paucity of access to consistent good‐quality historical observational data. The aim of this innovative project was to use classroom‐based participatory learning to help transcribe some of the many meteorological observations from Africa that are thus far unavailable to researchers. This project transcribed quickly and effectively station series by enrolling the help of second‐year undergraduate students at Maynooth University in Ireland. The newly digitized African data will increase the temporal and spatial coverage of data in this important data‐sparse region. Students gained new skills while helping the global scientific community unearth new insight into past African climate. The project managed to transcribe 79 months of data at Andapa in Madagascar and 56 months of data for Macenta in Guinea. The digitized data will be openly and freely shared with the scientific and wider community via the Pangaea data repository, the C3S Climate Data Store, and the National Oceanic and Atmospheric Administration's (NOAA) National Centers for Environmental Information (NCEI) data centre in the US. The project model has the potential for a broader roll‐out to other educational contexts and there is no shortage of data to be rescued. This paper provides details of the project, and all supporting information such as project guidelines and templates to enable other organizations to instigate similar programs.

Maritime historical documentary sources of weather and state of sea surface including sea ice can aid in filling a known climate knowledge gap for the Southern Ocean and Antarctica for the first half of the 20th century. This study presents a data set of marine climate, sea ice and icebergs recovered from a collection of logbooks from mainly Norwegian whaling factory ships that operated in the Southern Ocean during 1929–1940. The data set comprises some 8000 weather and 4000 sea ice/open sea records from austral summers of the study period. This paper further discusses the structure and content of most common Norwegian maritime documentary sources of the period along with the practices of logging information relevant for the study, such as time keeping, positioning and making weather observations. An emphasis was made on recovery of notes on sea ice and icebergs and their interpretation in terms of WMO categories of sea ice concentration. Data, including ship‐related metadata from all individual documents are homogenized and structured to a common machine‐readable format that simplifies its ingestion into relevant climate data depositories. [ABSTRACT FROM AUTHOR]

The majority of available climate data in global digital archives consist of data only from the 1940s or 1950s onwards, and many of these series have gaps and/or are available for only a subset of the variables which were actually observed. However, there exist billions of historical weather observations from the 1700s, 1800s, and early 1900s that are still in hard‐copy form and are at risk of being lost forever due to deterioration. An assessment of changes in climate extremes in several IPCC regions was not possible in IPCC AR6 WGI owing, in many cases, to the lack of available data. One such region is Africa, where the climate impact research and the ability to predict climate change impacts are hindered by the paucity of access to consistent good‐quality historical observational data. The aim of this innovative project was to use classroom‐based participatory learning to help transcribe some of the many meteorological observations from Africa that are thus far unavailable to researchers. This project transcribed quickly and effectively station series by enrolling the help of second‐year undergraduate students at Maynooth University in Ireland. The newly digitized African data will increase the temporal and spatial coverage of data in this important data‐sparse region. Students gained new skills while helping the global scientific community unearth new insight into past African climate. The project managed to transcribe 79 months of data at Andapa in Madagascar and 56 months of data for Macenta in Guinea. The digitized data will be openly and freely shared with the scientific and wider community via the Pangaea data repository, the C3S Climate Data Store, and the National Oceanic and Atmospheric Administration's (NOAA) National Centers for Environmental Information (NCEI) data centre in the US. The project model has the potential for a broader roll‐out to other educational contexts and there is no shortage of data to be rescued. This paper provides details of the project, and all supporting information such as project guidelines and templates to enable other organizations to instigate similar programs. [ABSTRACT FROM AUTHOR]

We describe the transcription and quality control processes for rescuing around 570,000 sub‐daily and daily weather observations which were recorded in the UK Met Office Daily Weather Reports during the 1861–1875 period. These data are from the start of coordinated weather observations and were collected with the aim of making the first‐ever weather forecasts. The observations were rescued thanks to 3500 volunteers and include sub‐daily sea‐level pressure, dry and wet bulb temperatures, daily maximum and minimum temperatures, and daily rainfall amounts from 70 different locations across Western Europe, and one in Canada. We highlight how these observations will be used to fill gaps in existing pressure and temperature datasets and use two case studies to show how the pressure observations will likely better constrain the atmospheric circulation during two severe storms. We also compare a sub‐sample of the newly rescued observations with data that were previously digitized for a small number of locations for the same dates, finding good agreement in general, although some discrepancies remain. [ABSTRACT FROM AUTHOR]

Data rescuers worldwide have been trying to retrieve millions of valuable weather historical records so the observations contained in those records are preserved, searchable, analysable and machine readable. The majority of the records are written by hand, in print or cursive handwriting. Automatic transcriptions to date have not been reliable or sufficiently accurate on handwritten data so most of the historical records are transcribed manually. Recent attempts integrate artificial intelligence (AI) to automatically transcribe the historical records but the results have not been promising. Currently there is no end‐to‐end workflow to automatically transcribe historical handwritten tabular records into digital datasets. We propose a workflow that uses AI to automate the handwriting transcription process. The workflow is tested using the historical climate records from the Data Rescue: Archives and Weather (DRAW) project. This workflow is composed of five steps: (1) image pre‐processing, (2) text line segmentation, (3) bounding boxes detection, (4) AI‐enabled optical character recognition (OCR) and (5) layout re‐arrangement. These steps are modular to better accommodate future advances (e.g., new image training data, better layout detectors). We hope the workflow proposed can serve as a guideline that is easily replicable and can be utilized to transcribe other historical datasets. [ABSTRACT FROM AUTHOR]

Abstract The number and coverage of weather observations over the oceans were considerably reduced during World War II (WW2) due to disruptions to normal trade routes. The observations that do exist for this period are often unavailable to science as they are still only available as paper records or scanned images. We have rescued the detailed hourly weather observations contained in more than 28,000 logbook images of the US Navy Pacific Fleet stationed at Hawai'i during 1941–1945 to produce a dataset of more than 630,000 records. Each record contains the date and time, positional information and several meteorological measurements, totalling more than 3 million individual observations. The data rescue process consisted of a citizen science project asking volunteers to transcribe the observations from the available images, followed by additional quality control processes. This dataset not only contains hourly weather observations of air temperature, sea surface temperature, atmospheric pressure, wind speed and wind direction, mainly in the Pacific Ocean but also includes some observations from the Atlantic and Indian Oceans. The new observations are found to be of good quality by inter‐comparing independent measurements taken on ships travelling in convoy and by comparing with the 20th‐Century Reanalysis. This dataset provides invaluable instrumental weather observations at times and places during WW2, which fill gaps in existing reconstructions.

The number and coverage of weather observations over the oceans were considerably reduced during World War II (WW2) due to disruptions to normal trade routes. The observations that do exist for this period are often unavailable to science as they are still only available as paper records or scanned images. We have rescued the detailed hourly weather observations contained in more than 28,000 logbook images of the US Navy Pacific Fleet stationed at Hawai'i during 1941–1945 to produce a dataset of more than 630,000 records. Each record contains the date and time, positional information and several meteorological measurements, totalling more than 3 million individual observations. The data rescue process consisted of a citizen science project asking volunteers to transcribe the observations from the available images, followed by additional quality control processes. This dataset not only contains hourly weather observations of air temperature, sea surface temperature, atmospheric pressure, wind speed and wind direction, mainly in the Pacific Ocean but also includes some observations from the Atlantic and Indian Oceans. The new observations are found to be of good quality by inter‐comparing independent measurements taken on ships travelling in convoy and by comparing with the 20th‐Century Reanalysis. This dataset provides invaluable instrumental weather observations at times and places during WW2, which fill gaps in existing reconstructions. [ABSTRACT FROM AUTHOR]

Abstract Daily weather observations measured by students and staff at Halkali Agricultural School (a school opened in 1892 on agriculture and animal husbandry during the Ottoman period) from 1896 to 1917 in Istanbul, Turkiye have been transcribed from the original publications into digital form and translated from Ottoman Turkish (the Perso‐Arabic script) to English (Latin alphabet). Over 55,000 observations of daily maximum, minimum and average temperature; rainfall, soil and under soil (0.25 m) temperature; humidity, pressure and wind speed were recovered. In addition, weather observations taken in Kandilli Observatory and Earthquake Research Institute from 1911 to 1936 and taken in Florya Meteorological Station from 1937 to 2022 could inform long‐term temperature changes in Istanbul. The publication of a new historical data set that includes, for the first time, digitized and quality‐controlled daily meteorological observations in Istanbul will enhance the understanding of weather changes in Turkiye back to the late 19th century. These observations will be used to fill gaps in existing temperature and pressure records and to the improvement of the accuracy of reanalysis products prior to the 1950s. It will be the first data set publication of other parameters such as soil temperature, wind speed and humidity for that period in that region. Data are available on the CEDA Archive in csv file format.

Abstract Extended hydrometric (water level and flow) records are presented for eight Irish catchments subject to arterial drainage. The procedures employed to collect and process historical data, extend flow records and compile key metadata and information about each gauging station are described. Procedures are developed to handle data quality issues related to hydrometric practices and equipment malfunction and to quality assure rescued data using quality codes that complement modern hydrometric practices. The workflow developed will assist other hydrometric data rescue efforts and minimize subjectivity during the rescue process. The newly extended records represent the longest continuous river flow series available in Ireland, extending to the commencement of formal hydrometric monitoring in the country in 1940. The resultant data sets add 150 years of daily data across eight stations and will provide a key new resource for hydrological studies into the impacts of arterial drainage and flow nonstationarity.

Extended hydrometric (water level and flow) records are presented for eight Irish catchments subject to arterial drainage. The procedures employed to collect and process historical data, extend flow records and compile key metadata and information about each gauging station are described. Procedures are developed to handle data quality issues related to hydrometric practices and equipment malfunction and to quality assure rescued data using quality codes that complement modern hydrometric practices. The workflow developed will assist other hydrometric data rescue efforts and minimize subjectivity during the rescue process. The newly extended records represent the longest continuous river flow series available in Ireland, extending to the commencement of formal hydrometric monitoring in the country in 1940. The resultant data sets add 150 years of daily data across eight stations and will provide a key new resource for hydrological studies into the impacts of arterial drainage and flow nonstationarity. [ABSTRACT FROM AUTHOR]

Daily weather observations measured by students and staff at Halkali Agricultural School (a school opened in 1892 on agriculture and animal husbandry during the Ottoman period) from 1896 to 1917 in Istanbul, Turkiye have been transcribed from the original publications into digital form and translated from Ottoman Turkish (the Perso‐Arabic script) to English (Latin alphabet). Over 55,000 observations of daily maximum, minimum and average temperature; rainfall, soil and under soil (0.25 m) temperature; humidity, pressure and wind speed were recovered. In addition, weather observations taken in Kandilli Observatory and Earthquake Research Institute from 1911 to 1936 and taken in Florya Meteorological Station from 1937 to 2022 could inform long‐term temperature changes in Istanbul. The publication of a new historical data set that includes, for the first time, digitized and quality‐controlled daily meteorological observations in Istanbul will enhance the understanding of weather changes in Turkiye back to the late 19th century. These observations will be used to fill gaps in existing temperature and pressure records and to the improvement of the accuracy of reanalysis products prior to the 1950s. It will be the first data set publication of other parameters such as soil temperature, wind speed and humidity for that period in that region. Data are available on the CEDA Archive in csv file format. [ABSTRACT FROM AUTHOR]

The recovery of early records of maximum, minimum, and mean temperatures; pressure; and relative humidity measurements in Puerto Madryn for the period 1902–1915 is presented. A careful evaluation of the quality of the data was performed using internal coherence, tolerance, and temporal consistency tests. The monthly mean series of all the variables, constructed from daily raw data, were subject to several homogeneity tests, and only discontinuities in pressure and relative humidity were found. The homogenized monthly mean series were compared with the Twentieth Century Reanalysis series in annual and seasonal time steps. In addition, the trends of each variable were assessed using the Mann–Kendall procedure, and correlations between relative humidity and the other variables were examined. The results show a remarkably good agreement between the temperature measurements and reanalysis values with a Spearman correlation coefficient of 0.94. The raw data for minimum and maximum temperatures represent a very good upper and lower bound for the mean temperature values of both observational and reanalysis data. Agreement was found to be lower for relative humidity and pressure with the correlation coefficients being close to 0.6 in both cases. No trends were found for the variables. The correlation analysis of the humidity measurements with the other variables shows an inverse dependence of the temperatures and no relatedness with the pressure values. [ABSTRACT FROM AUTHOR]

A climate analysis of the monthly mean temperatures of Southern Patagonia during the late-XIXth and early-XXth centuries was carried out as part of the international data rescue Atmospheric Circulation Reconstructions over the Earth (ACRE) program partnership in Argentina, together with other data sources with regional and global records. The data from these diverse sources were combined to carry out a study in the coastal region of Patagonia, including Tierra del Fuego, between 42° S and 55° S for 11 locations. Furthermore, HadSST monthly/seasonal fields during the period 1880–1920 were also used. Both mean monthly and seasonal temperature values and timeseries variability were considered. Their analysis shows consistent behavior within the study region and compared to Southern Hemisphere mean results, which are characterized by a warm late-XIX century and a cooler early-XX century. This is also in agreement with SST variability along the coasts of Patagonia and hemispheric records. A comparison with present-day observations, where available, also yields consistent behavior. Low-frequency variability, i.e., in periods longer than 3 years, during the study period is consistent with present variability. Trend estimates at Trelew and Rio Gallegos for the period 1901–2020 yield significant trends, consistent with hemispheric warming at their latitudes. [ABSTRACT FROM AUTHOR]

A historical atmospheric reanalysis from 1850 to 2015 was performed using an atmospheric general circulation model assimilating surface pressure observations archived in international databases, with perturbed observational sea surface temperatures as a lower boundary condition. Posterior spread during data assimilation provides quantitative information on the uncertainty in the historical reanalysis. The reanalysis reproduces the evolution of the three-dimensional atmosphere close to those of the operational centers. Newly archived surface pressure observations greatly reduced the uncertainties in the present reanalysis over East Asia in the early 20th century. A scheme for assimilating tropical cyclone tracks and intensities was developed. The scheme was superior to the present several reanalyses in reproducing the intensity close to the observations and the positions. The reanalysis provides possible images of atmospheric circulations before reanalyses with full-scale observations become available, and opportunities for investigating extreme events that occurred before World War II. Incorporating dynamical downscaling with a regional model that includes detailed topography and sophisticated physics is an application of historical reanalysis to reveal the details of past extreme events. Some examples of past heavy rainfall events in Japan are shown using a downscaling experiment, together with dense rainfall observations over the Japanese islands. [ABSTRACT FROM AUTHOR]

Basel and Geneva have two of the longest meteorological records in Switzerland, covering more than two and a half centuries. The respective monthly temperature series were published over 60 years ago and are part of todays main global temperature data sets. After digitizing the raw sub-daily measurements, we rebuilt the early instrumental part (i.e., before 1864) of the two series at daily resolution using modern methods and additional data sources that were not considered in previous efforts. A comparison with the old series and with other existing recontructions show a generally good agreement only for the last 30 years. Before the 1830s a few systematic differences appear, particularly in summer, suggesting that both new and old versions contain residual inhomogeneities. We use the new series together with other reconstructions to analyze the periods 1791–1807 and 1808–1824, which have been described, respectively, as a warm and cold period in summer in previous studies. Our results suggest that most existing instrumental data sets tend to overestimate summer temperature in Switzerland during the former period, confirming previous results based on proxy records. The overestimation is particularly large (almost 1 °C) in the old Geneva series. On the other hand, we find a probable systematic underestimation of summer temperature in our Basel series. Before the 1780s the agreement between existing reconstructions is poor, so that it is hardly possible to make confident statements about climate variability for the first few decades covered by the series. Nevertheless, the daily resolution of the data allows an insight into individual meteorological events such as cold spells and heat waves.

Purpose: Upcycling is conceptualised as a digital historical research practice aimed at increasing the scientific value of historical data collections produced in print or in electronic form between the eighteenth and the late twentieth centuries. The concept of upcycling facilitates data rescue and reuse as well as the study of information creation processes deployed by previous generations of researchers. Design/methodology/approach: Based on a selection of two historical reference works and two legacy collections, an upcycling workflow consisting of three parts (input, processing and documentation and output) is developed. The workflow facilitates the study of historical information creation processes based on paradata analysis and targets the cognitive processes that precede and accompany the creation of historical data collections. Findings: The proposed upcycling workflow furthers the understanding of computational methods and their role in historical research. Through its focus on the information creation processes that precede and accompany historical research, the upcycling workflow contributes to historical data criticism and digital hermeneutics. Originality/value: Many historical data collections produced between the eighteenth and the late twentieth century do not comply with the principles of FAIR data. The paper argues that ignoring the work of previous generations of researchers is not an option, because it would make current research practices more vulnerable and would result in losing access to the experiences and knowledge accumulated by previous generations of scientists. The proposed upcycling workflow takes historical data collections seriously and makes them available for future generations of researchers. [ABSTRACT FROM AUTHOR]

Abstract Coastal water level measurements represent one of the earliest geophysical measurements and allow an assessment of historical sea level rise and trends in tides, river flow and storm surge. However, recovery and digitization of archival tidal records have been much less widespread and systematic than, for example meteorological records. In this contribution, we discuss data rescue efforts and lessons learned in France, the United States and the United Kingdom, countries with early and extensive tide gauge networks by the mid‐19th century. We highlight the importance of (a) cataloguing the historical gauge records, as a first step towards locating them; (b) locating data in archives, and then recovering and saving data by any means necessary, including photographs and scanning; (c) obtaining metadata, including both quantitative survey records, gauge checks and clock data, but also qualitative records such as gauge notes, letters and reports; and (d) quantitative statistical analysis of data and datum quality, using both standard data‐entry checks but also tools that leverage the unique predictability of tide measurements. Methods for digitizing original analogue records are also discussed, including semi‐automatic, computer‐based methods of digitizing tidal charts (marigrams). Although the current best practice is described, future improvements are desirable and needed to make the more than estimated 10,000 station years of unused, undigitized records available to the scientific community.

Abstract Millions of sub‐daily sea‐level pressure observations taken between 1919 and 1960 over the British and Irish Isles were transcribed from paper records in the early 2000s but were not published and subsequently forgotten. A chance discussion led to the rediscovery of the transcribed data and 5.47 million observations from 160 locations are now made available, although the data have not been fully quality‐controlled. Much of the data are 3‐hourly, allowing for detailed examinations of synoptic weather variations for this region and time period, and will be invaluable for constraining future reanalyses. We illustrate the value of the data using a stormy period during October and November 1928 and discuss the remaining quality‐control issues.

A distinction is made between data rescue (i.e., copying, digitizing, and archiving) and data recovery that implies deciphering, interpreting, and transforming early instrumental readings and their metadata to obtain high-quality datasets in modern units. This requires a multidisciplinary approach that includes: palaeography and knowledge of Latin and other languages to read the handwritten logs and additional documents; history of science to interpret the original text, data, and metadata within the cultural frame of the 17th, 18th, and early 19th centuries; physics and technology to recognize bias of early instruments or calibrations, or to correct for observational bias; and astronomy to calculate and transform the original time in canonical hours that started from twilight. The liquid-in-glass thermometer was invented in 1641 and the earliest temperature records started in 1654. Since then, different types of thermometers have been invented, based on the thermal expansion of air or selected thermometric liquids with deviation from linearity. Reference points, thermometric scales, and calibration methodologies were not comparable, and not always adequately described. Thermometers had various locations and exposures, e.g., indoor, outdoor, on windows, gardens or roofs, facing different directions. Readings were made only one or a few times a day, not necessarily respecting a precise time schedule: this bias is analysed for the most popular combinations of reading times. The time was based on sundials and local Sun, but the hours were counted starting from twilight. In 1789–1790, Italy changed system and all cities counted hours from their lower culmination (i.e., local midnight), so that every city had its local time; in 1866, all the Italian cities followed the local time of Rome; in 1893, the whole of Italy adopted the present-day system, based on the Coordinated Universal Time and the time zones. In 1873, when the International Meteorological Committee (IMC) was founded, later transformed into the World Meteorological Organization (WMO), a standardization of instruments and observational protocols was established, and all data became fully comparable. In dealing with the early instrumental period, from 1654 to 1873, the comparison, correction, and homogenization of records is quite difficult, mainly because of the scarcity or even absence of metadata. This paper deals with this confused situation, discussing the main problems, but also the methodologies to recognize missing metadata, distinguish indoor from outdoor readings, correct and transform early datasets in unknown or arbitrary units into modern units, and, finally, in which cases it is possible to reach the quality level required by the WMO. The aim is to explain the methodology needed to recover early instrumental records, i.e., the operations that should be performed to decipher, interpret, correct, and transform the original raw data into a high-quality dataset of temperature, usable for climate studies. [ABSTRACT FROM AUTHOR]

Abstract Recovering additional historical weather observations from known archival sources will improve the understanding of how the climate is changing and enable detailed examination of unusual events within the historical record. The UK National Meteorological Archive recently scanned more than 66,000 paper sheets containing 5.28 million hand‐written monthly rainfall observations taken across the UK and Ireland between 1677 and 1960. Only a small fraction of these observations were previously digitally available for climate scientists to analyse. More than 16,000 volunteer citizen scientists completed the transcription of these sheets of observations during early 2020 using the RainfallRescue.org website, built using the Zooniverse platform. A total of 3.34 million observations from more than 6000 locations have so far been quality controlled and made openly available. This has increased the total number of monthly rainfall observations that are available for this time period and region by a factor of six. The newly rescued observations will enable longer and much improved reconstructions of past variations in rainfall across the British and Irish Isles, including for periods of significant flooding and drought. Specifically, this data should allow the official gridded monthly rainfall reconstructions for the UK to be extended back to 1836, and even earlier for some regions.

Abstract Individual sunspot observations have formed a ground basis of international sunspot number, a unique reference for long‐term solar variability in the centennial timescale. The original datasets were subjected to exploitations and analyses upon the recalibrations of the sunspot number series. In this context, this study reviewed and analysed original sunspot records and their databases in the Kawaguchi Science Museum (KSM) in Japan. KSM hosts sunspot drawings and logbooks from 1972 to 2013. This dataset has a longer chronological coverage than what was known to the scientific community (1981–2010). These records have been digitized and publicized in a museum database, which allows users to access individual sunspot drawings and numerical data in KSM logbooks. These records are highly homogeneous as a single observer's dataset (Hitoshi Takuma), who used a 15‐cm refractor at the Kawaguchi Juvenile Museum in 1972–2003 and a 20‐cm refractor at KSM in 2003–2013. We also reviewed the Takuma data series, his monthly observation days (21.3 days/month), sunspot number in the whole disk and each hemisphere, and sunspot positions in a butterfly diagram. We also assessed Takuma's data stability in comparison with the international sunspot number and reference datasets of the SILSO. Takuma's data appear stable until 2003, when he changed the observation site and instrument. His data stability was quantitatively compared with the SILSO reference datasets, confirming the substantial long‐term stability of the data and establishing its reliability as an alternative reference for sunspot number recalibration.

Coastal water level measurements represent one of the earliest geophysical measurements and allow an assessment of historical sea level rise and trends in tides, river flow and storm surge. However, recovery and digitization of archival tidal records have been much less widespread and systematic than, for example meteorological records. In this contribution, we discuss data rescue efforts and lessons learned in France, the United States and the United Kingdom, countries with early and extensive tide gauge networks by the mid‐19th century. We highlight the importance of (a) cataloguing the historical gauge records, as a first step towards locating them; (b) locating data in archives, and then recovering and saving data by any means necessary, including photographs and scanning; (c) obtaining metadata, including both quantitative survey records, gauge checks and clock data, but also qualitative records such as gauge notes, letters and reports; and (d) quantitative statistical analysis of data and datum quality, using both standard data‐entry checks but also tools that leverage the unique predictability of tide measurements. Methods for digitizing original analogue records are also discussed, including semi‐automatic, computer‐based methods of digitizing tidal charts (marigrams). Although the current best practice is described, future improvements are desirable and needed to make the more than estimated 10,000 station years of unused, undigitized records available to the scientific community. [ABSTRACT FROM AUTHOR]

Millions of sub‐daily sea‐level pressure observations taken between 1919 and 1960 over the British and Irish Isles were transcribed from paper records in the early 2000s but were not published and subsequently forgotten. A chance discussion led to the rediscovery of the transcribed data and 5.47 million observations from 160 locations are now made available, although the data have not been fully quality‐controlled. Much of the data are 3‐hourly, allowing for detailed examinations of synoptic weather variations for this region and time period, and will be invaluable for constraining future reanalyses. We illustrate the value of the data using a stormy period during October and November 1928 and discuss the remaining quality‐control issues. [ABSTRACT FROM AUTHOR]

At-risk data is an unfortunate research reality and can be present in all data formats in a range of research disciplines. This is defined as data that are at risk of loss due to various factors, including deterioration of the media, lack of accompanying documentation and data that exists in non-digital formats, which are often irreplaceable. Continued access to older data has a range of benefits. The factors that place valuable data at risk are therefore a cause for concern. This paper reports on a multi-method case study, comprising a survey and interviews. A web-based questionnaire was distributed to all research group leaders based at a leading South African research institute. This was followed by one-on-one interviews that were held with a sub-section of the same group of researchers. The combined findings of the two methods enabled a picture to be formed regarding factors that jeopardise research data, data rescue obstacles that the researchers encountered and the state of data rescue at the institute. Several recommendations and strategies are put forward to address identified risk factors and challenges. Suggestions include the launch of a data rescue project, awareness training around data at risk, involving the institute’s library and information services (LIS) section in data rescue and launching continued efforts to acquire a dedicated institutional data repository. It is also important to ensure that the scope of project risk management includes data considerations. The combined implementation of recommendations is anticipated to ensure the accessibility and usability of older at-risk data and reduce the chances of current and future data becoming compromised.

Recovering additional historical weather observations from known archival sources will improve the understanding of how the climate is changing and enable detailed examination of unusual events within the historical record. The UK National Meteorological Archive recently scanned more than 66,000 paper sheets containing 5.28 million hand‐written monthly rainfall observations taken across the UK and Ireland between 1677 and 1960. Only a small fraction of these observations were previously digitally available for climate scientists to analyse. More than 16,000 volunteer citizen scientists completed the transcription of these sheets of observations during early 2020 using the RainfallRescue.org website, built using the Zooniverse platform. A total of 3.34 million observations from more than 6000 locations have so far been quality controlled and made openly available. This has increased the total number of monthly rainfall observations that are available for this time period and region by a factor of six. The newly rescued observations will enable longer and much improved reconstructions of past variations in rainfall across the British and Irish Isles, including for periods of significant flooding and drought. Specifically, this data should allow the official gridded monthly rainfall reconstructions for the UK to be extended back to 1836, and even earlier for some regions. [ABSTRACT FROM AUTHOR]

Abstract In situ data are an essential need in the analyses of past and current climate change. All over the world, different data rescue activities try to extend existing time series and to retrieve data in spatial and temporal data sparse regions. Also in Europe, part of the historic data is still only available in paper archives, without any digital access to these sources. The EUMETNET Data Rescue activity was started in order to investigate the potential for additional long‐term stations, to monitor the progress of data rescue in European countries and to support participants with know‐how exchange and international connections to facilitate data exchange. The activity raised the awareness of the need for data rescue and ongoing activities. This paper will provide information on the data rescue activities of 4 EUMETNET countries focusing on different aspects and in different states of the data rescue process. While Austria, Croatia and Slovenia are connected by a partly common history which is also displayed in the history of their meteorological network, Catalonia has a different historical background. Nevertheless, the problems data rescue is confronted with are similar for all activities. Therefore, the selected countries will provide a good overview of the problems and solutions discussed during the EUMETNET meetings. This paper wants to offer insight into different strategies for data rescue as well as into ongoing activities. Moreover, the importance of cooperation in regard to data rescue is underlined and examples of possible partnerships are provided.

The ‘Digital Index of North American Archaeology’ (DINAA) project demonstrates how the aggregation and publication of government-held archaeological data can help to document human activity over millennia and at a continental scale. These data can provide a valuable link between specific categories of information available from publications, museum collections and online databases. Integration improves the discovery and retrieval of records of archaeological research currently held by multiple institutions within different information systems. It also aids in the preservation of those data and makes efforts to archive these research results more resilient to political turmoil. While DINAA focuses on North America, its methods have global applicability.

Abstract This article presents daily rainfall data and metadata for Ireland transcribed from historical manuscript and printed copies of rainfall registers located in Met Éireann's archives. To facilitate the transcription of rainfall observations from paper records, the historical manuscripts were scanned and integrated into Met Éireann's digital archives. The transcription from digital image to data format was undertaken in collaboration with students at Maynooth University as part of a novel crowdsourcing initiative to integrate data rescue activities into the classroom. In total, 3,616 station years of rainfall data (~1.32 million daily values) were transcribed. The data, which was double keyed, have undergone basic quality assurance to check for transcription errors and the resultant raw data and associated metadata are presented here. Ongoing work involves the application of further quality assurance and homogenization techniques to develop a long‐term, quality assured daily rainfall network for Ireland.

Knowledge of long‐term changes in climate extremes is vital to better understand climate variability and place present day extreme events in historical context. Analysis of trends in extreme precipitation in Ireland have largely been limited to the second half of the 20th century due to lack of data availability in digital format. Using recently digitized data, this study provides the first assessment of long‐term changes in extreme daily precipitation observed at 30 locations across Ireland. Quality control of rescued data is carried out before selected long‐term stations are tested for homogeneity using the RHtests software. Details of detected breakpoints and the application of adjustments to daily values are discussed. Eleven extreme precipitation indices are calculated on an annual basis and analysed to determine spatial and temporal trends in the frequency, intensity and magnitude of observed precipitation. The persistence of trends for varying record lengths and for two fixed periods (1910–2019 and 1940–2019) of analysis is assessed for all stations and indices. Results show increases in precipitation intensity, especially notable in the east and southeast of the island. Our findings also show that the contribution of heavy and extreme precipitation events to annual totals is increasing, while there was no persistent trends in annual totals or consecutive wet or dry days. [ABSTRACT FROM AUTHOR]

In situ data are an essential need in the analyses of past and current climate change. All over the world, different data rescue activities try to extend existing time series and to retrieve data in spatial and temporal data sparse regions. Also in Europe, part of the historic data is still only available in paper archives, without any digital access to these sources. The EUMETNET Data Rescue activity was started in order to investigate the potential for additional long‐term stations, to monitor the progress of data rescue in European countries and to support participants with know‐how exchange and international connections to facilitate data exchange. The activity raised the awareness of the need for data rescue and ongoing activities. This paper will provide information on the data rescue activities of 4 EUMETNET countries focusing on different aspects and in different states of the data rescue process. While Austria, Croatia and Slovenia are connected by a partly common history which is also displayed in the history of their meteorological network, Catalonia has a different historical background. Nevertheless, the problems data rescue is confronted with are similar for all activities. Therefore, the selected countries will provide a good overview of the problems and solutions discussed during the EUMETNET meetings. This paper wants to offer insight into different strategies for data rescue as well as into ongoing activities. Moreover, the importance of cooperation in regard to data rescue is underlined and examples of possible partnerships are provided. [ABSTRACT FROM AUTHOR]

For years scientists in fields from climate change to biodiversity to hydrology have used older data to address contemporary issues. Since the 1960s researchers, recognizing the value of this data, have expressed concern about its management and potential for loss. No widespread solutions have emerged to address the myriad issues around its storage, access, and findability. This paper summarizes observations and concerns of researchers in various disciplines who have articulated problems associated with analog data and highlights examples of projects that have used historical data. The authors also examined selected papers to discover how researchers located historical data and how they used it. While many researchers are not producing huge amounts of analog data today, there are still large volumes of it that are at risk. To address this concern, the authors recommend the development of best practices for managing historic data. This will take communication across disciplines and the involvement of researchers, departments, institutions, and associations in the process.

Abstract We describe the digitization of 1.8 million sub‐daily and daily weather observations which were recorded in the UK Met Office Daily Weather Reports during the 1900–1910 period. The data were rescued from scanned images of the original documents by 2,148 volunteer citizen scientists using the weatherrescue.org website. The rescued observations include dry and wet bulb temperatures, daily maximum and minimum temperatures, daily rainfall amounts and sub‐daily sea‐level pressure from 72 different locations across western Europe. These observations will be used to fill gaps in existing pressure, temperature and rainfall records and are one of the largest recoveries of weather data by citizen scientists. The value of these additional observations is highlighted by comparing the pressure observations to the Twentieth Century Reanalysis version 3 ensemble for some specific case studies.

Abstract This project compiled 463,530 instrumental observations of daily temperature, precipitation and sunshine at up to 319 stations in China between 1912 and 1951. The principal sources are monthly reports of the Institute of Meteorology, Nanjing, observatories in Japanese‐occupied Manchuria, and the Japanese Army in North China. Gross errors, rounding errors and inhomogeneities are identified. The new dataset is temporally and spatially consistent with existing datasets of monthly temperature, but reports higher precipitation and sunshine.

Much older soils information, collectively known as legacy soils data lies idle in libraries or in the personal collections of retired soil scientists. The probability is very high for this legacy data to be lost or destroyed. We demonstrate the stepwise process of bringing legacy soils data “back to life” using the Reconnaissance Soil Survey of the Busia Area (quarter degree sheet No. 101) in western Kenya as an example. The first step, site identification, involves meeting and deliberating with key institutions to identify a setting for the study. The second step, data archeology, involves locating and cataloging legacy soil data from key institutions, which often requires numerous site visits and the assistance of individuals familiar with the target data. The third step, data rescue, involves converting paper copies of data into a digital format by scanning the maps, narrative descriptions, and tables, and storing the information in a database. The fourth step, data renewal, consists of bringing the data to modern standards by taking advantage of technological and conceptual advances in geoinformation technology. In our example, the resulting digital (scanned) soil map of the Busia Area is a significant upgrade from the fragile paper map. The fifth step, data interpretation, entails careful interpretation of the soil information available within the legacy soil survey to provide additional agronomic information. This allowed us to produce 10 land quality maps showing the ability of the land to perform specific agronomic functions, and 18 different crop suitability maps that were not previously available. The rescued maps and their associated tabular and narrative data also provide crucial inputs for generating more detailed soil maps using digital soil mapping techniques that were unavailable when the original mapping was conducted.

We demonstrate that data abstraction via a timeline visualization is highly effective at allowing one to discover patterns in the underlying data. We describe the rapid identification of data gaps in the archival time-series records of deep-ocean pressure and coastal water level observations collected to support the NOAA Tsunami Program and successful measures taken to rescue these data. These data gaps had persisted for years prior to the development of timeline visualizations to represent when data were collected. This approach can be easily extended to all types of time-series data and the author recommends this type of temporal visualization become a routine part of data management, whether one collects data or archives data.

Beginning in 1964, an academic lineage of Robert DuBois and his students, Daniel Wolfman and Jeffrey Eighmy, developed dedicated United States‐based archaeomagnetic research programs. Collectively, they analyzed over 5,377 archaeomagnetic sites, primarily from North America, dated to less than 2,000 years old. Yet despite their decades of effort, few journal publications resulted. Most of their published results are embedded in archeological reports, often without technical data, which limits the data's accessibility. Furthermore, when published, the results are generally averaged at the site level using statistical conventions different from today's standards, limiting the data's comparability and (re)usability. In 2015, we undertook a salvage archival study to digitize the surviving data and metadata from the scientists' individual estates and emeritus collections. We digitized measurement data from more than 51,000 specimens, reinterpreted them using modern conventions, and uploaded them to the FAIR‐adhering magnetic data repository, earthref.org/MagIC. The reinterpreted site‐level results from the three laboratories are mutually consistent, permitting the individual data sets to be combined and analyzed as single regional entities. Through incorporation into the MagIC repository, these legacy data are now accessible for incorporation into archaeomagnetic and global magnetic field modeling efforts, critical to understanding Earth's magnetic field variation through time. In the Four Corners region of the United States Southwest, this digitized archive advances the development of a new regional paleosecular variation curve used in archaeomagnetic dating. This project highlights both the value and complexities of managing legacy data; the many lessons learned to set a precedent for future paleomagnetic data recovery efforts. Plain Language Summary: Archaeomagnetism is the study of Earth's past magnetic field through researching the magnetic signatures retained in well‐dated archeological materials. The most commonly studied materials are those that have experienced high temperatures due to human‐made fires. Due to humans' global occupation, there is a potential for globally distributed archaeomagnetic sampling, which is essential for high‐resolution global magnetic field models. However, there is considerable variation in the documentation and accessibility of data from certain regions, including North America. In 2015, a salvage archival project was initiated to recover the life's work of three North American archaeomagnetists. The effort resulted in the digitization and formatting of the data within DuBois' and Wolfman's estates, and Eighmy's archive. In total, measurement data from more than 51,000 specimens, from 5,377 archeological features, were processed and uploaded to a centralized online data repository, MagIC. This repository ensures that the data, representing 130 person‐years of work, are now findable and accessible, permitting the data to be re‐used in future modeling projects. One such application for these data is the development of a new regional model for the Four Corners region of the United States Southwest that traces the location of the magnetic north pole through time. Key Points: We digitized 6 decades of legacy archaeodirectional measurements from three archives (>51k specimens), adding them to a FAIR repository, MagICThe site‐level results (reanalyzed using modern statistical conventions) are consistent between the archivesThe majority of the data have site provenance in North America and are dated to less than 2,000 years old [ABSTRACT FROM AUTHOR]

There is a growing interest in the rescue and reuse of data from past studies (so‐called legacy data). Data loss is alarming, especially where natural archives are under threat, such as peat deposits. Here we develop a workflow for reuse of legacy radiocarbon dates in peatland studies, including a rigorous quality assessment that can be tailored to specific research questions and study regions. A penalty is assigned to each date based on criteria that consider taphonomic quality (i.e., sample provenance) and dating quality (i.e., sample material and method used). The weights of quality criteria may be adjusted based on the research focus, and resulting confidence levels may be used in further analyses to ensure robustness of conclusions. We apply the proposed approach to a case study of a (former) peat landscape in the Netherlands, aiming to reconstruct the timing of peat initiation spatially. Our search yielded 313 radiocarbon dates from the 1950s to 2019. Based on the quality assessment, the dates—of highly diverse quality—were assigned to four confidence levels. Results indicate that peat initiation for the study area first peaked in the Late Glacial (~14,000 cal years BP), dropped during the Boreal (~9,500 cal years BP) and showed a second peak in the Subboreal (~4,500 cal years BP). We tentatively conclude that the earliest peak was mostly driven by climate (Bølling–Allerød interstadial), whereas the second was probably the result of Holocene sea level rise and related groundwater level rise in combination with climatic conditions (hypsithermal). Our study highlights the potential of legacy data for palaeogeographic reconstructions, as it is cost‐efficient and provides access to information no longer available in the field. However, data retrieval may be challenging, and reuse of data requires that basic information on location, elevation, stratigraphy, sample and laboratory analysis are documented irrespective of the original research aims. [ABSTRACT FROM AUTHOR]

Abstract Historical weather observations on the daily scale are vital for the improvement of reanalysis products and the analysis of long‐term variability of extreme events. While daily datasets extend for several centuries in parts of the Northern Hemisphere, the majority of historical data for the Southern Hemisphere are monthly averages or totals. In this paper, we describe a newly recovered dataset of ten daily meteorological variables for 1877 to 1922 from Eversleigh, a property in the New England region of New South Wales in Australia. Here, we present the full process of data rescue, from digitization to quality control and an assessment of homogeneity. We show that the majority of variables were recorded to a high standard and that the data are of general use for climate analysis. Forty years of daily temperature, cloud cover, wind, and pressure observations are now available for the New England Plateau, offering data that are more complete than any other records for the region in the Australian Bureau of Meteorology dataset. The Eversleigh dataset now provides an opportunity to gain more insight into the 19th century weather and climate of eastern Australia during a time of large interannual climate variability before the dominant impact of an anthropogenic warming signal.

Abstract Historical ship logbooks provide vital historic meteorological observations in the Southern Ocean, one of the largest climate‐data deficient regions on the Earth. Christian Salvesen Whaling Company logbooks from whaling ships operating in the Southern Ocean, starting from the 1930s through the 1950s, are examined. Meteorological information contained in these logbooks has been extracted to produce a historical climate dataset. We discuss various instructions recommended by the British Admiralty to observe and record weather conditions on‐board whaling ships. Statistical tests were used to flag erroneous values and corrections were made using neighbouring values. Meteorological parameters such as air pressure, air and sea temperature and wind force on the Beaufort scale were standardized, converting imperial to metric units. The data were structured according to the internationally accepted International Maritime Meteorological Archive format, which includes the most commonly reported meteorological variables, including the time, location and ship‐related meta‐data. Hence, a readily accessible, error‐corrected and standardized historical climate dataset of the Weddell Sea sector of the Southern Ocean is presented. Open Practices This article has earned an Open Data badge for making publicly available the digitally‐shareable data necessary to reproduce the reported results. The data is available at https://doi.org/10.17863/CAM.31530. Learn more about the Open Practices badges from the Center for Open Science: https://osf.io/tvyxz/wiki.

Abstract Historical data provides observational information crucial to our understanding of the evolution of geophysical processes. However, there is a gap between predigital age observations, which are typically handwritten, and data that is discoverable and analysable. The data rescue protocols here address this gap, covering the information lifecycle from handwritten register pages to transcription‐ready content, describing the historical data, the database design for the data rescue, and the development of an application design to transcribe the meteorological information directly from an image file to the database. The preparatory steps necessary to organize, curate, image, and structure the meteorological information, prior to transcribing the historical data, are outlined here in an integrated methodology. The initial organization, the development of an image file nomenclature to link the rescued data to the original source, and the description of a metadata schema to optimize the transcription application are all vital to the process of ensuring traceability and transparency in the data rescue process. Taken together, these steps describe best practices guidelines for similar projects. Although we designed the methodology and application to be used in any data rescue context, our particular concern was to accommodate the needs of citizen scientists. We thus focused on making our application easily maintained, flexible, direct to database, clear, and simple to use. Open Practices This article has earned an Open Data badge for making publicly available the digitally‐shareable data necessary to reproduce the reported results. The data is available at https://citsci.geog.mcgill.ca. Learn more about the Open Practices badges from the Center for Open Science: https://osf.io/tvyxz/wiki.

This article presents daily rainfall data and metadata for Ireland transcribed from historical manuscript and printed copies of rainfall registers located in Met Éireann's archives. To facilitate the transcription of rainfall observations from paper records, the historical manuscripts were scanned and integrated into Met Éireann's digital archives. The transcription from digital image to data format was undertaken in collaboration with students at Maynooth University as part of a novel crowdsourcing initiative to integrate data rescue activities into the classroom. In total, 3,616 station years of rainfall data (~1.32 million daily values) were transcribed. The data, which was double keyed, have undergone basic quality assurance to check for transcription errors and the resultant raw data and associated metadata are presented here. Ongoing work involves the application of further quality assurance and homogenization techniques to develop a long‐term, quality assured daily rainfall network for Ireland. [ABSTRACT FROM AUTHOR]

We combine archival research, semi‐analytical models, and numerical simulations to address the following question: how do changes to channel geometry alter tidal properties and flood dynamics in a hyposynchronous, strongly frictional estuary with a landward decay in tidal amplitudes? Records in the Saint Johns River Estuary since the 1890s show that tidal range has doubled in Jacksonville, Florida. Near the estuary inlet, tidal discharge approximately doubled but tidal amplitudes increased only ∼6%. Modeling shows that increased shipping channel depths from ∼5 to ∼13m drove the observed changes, with other factors like channel shortening and width reduction producing comparatively minor effects. Tidal amplitude increases are spatially variable, with a maximum change 20–25 km from the estuary inlet; tidal theory suggests that increases in amplitude approximately follow xexp(μx), where x is the distance from the ocean and μ is a damping coefficient. Tidal changes are a predictor of altered surge dynamics: Numerical modeling of hurricane Irma under 1898 and 2017 bathymetric conditions confirms that both tidal and storm surge amplitudes are larger today, with a similar spatial pattern. Nonetheless, peak water levels are simulated to be larger under 1898 bathymetry. The cause is likely the record river discharge observed during the storm; as suggested by a subtidal water‐level model, channel deepening since 1898 appears to have reduced the average surface slope required to drain both mean river flow and storm flows toward the ocean. Nonetheless, results suggest an increased vulnerability to storms with less river flow, but larger storm surge. Plain Language Summary: In this study, we evaluate whether channel deepening and other geometric changes have altered the effects of tides, storm surge, and river flow within the lower Saint Johns River Estuary, Florida, USA. Using data from archives and old reports, we find that tidal range has more than doubled in some locations since the late 1800s. Further, the average water level difference between Jacksonville, Florida and the coast appears to have decreased, while tidal velocities and discharge have increased. Numerical and analytical models show that the primary cause is channel deepening and dredging; other factors, such as shortening the channel, have comparatively minor influence. Using the numerical model, we simulated the effects of hurricane Irma under both modern and historic (1900 Era) geometry. Results show that the storm surge from hurricane Irma was higher today than it would have been a century ago. However, overall water levels in Jacksonville were simulated to be 0.2 m less today than historically, since the deeper channel enabled the record amount of rainfall, runoff, and wind‐induced currents from the storm to exit toward the ocean more easily. Hence, anthropogenic development of estuarine waterways can both decrease the hazard from river‐based floods, while increasing the marine‐sourced hazard. Key Points: Tidal range amplifies after channel deepening in a strongly frictional estuary, with a peak increase near the damping lengthscaleStorm surge amplitudes evolve similarly to tides, with a similar spatial pattern and location of maximum changeExtreme water levels caused by river discharge have likely decreased due to bathymetric change [ABSTRACT FROM AUTHOR]

Sea level in the South Atlantic Ocean has only been measured at a small number of tide‐gauge locations, which causes considerable uncertainty in 20th‐century sea‐level trend estimates in this basin. To obtain a better‐constrained sea‐level trend in the South Atlantic Ocean, this study aims to answer two questions. The first question is: can we combine new observations, vertical land motion estimates, and information on spatial sampling biases to obtain a likely range of 20th‐century sea‐level rise in the South Atlantic? We combine existing observations with recovered observations from Dakar and a high‐resolution sea‐level reconstruction based on salt‐marsh sediments from the Falkland Islands and find that the rate of sea‐level rise in the South Atlantic has likely been between 1.1 and 2.2 mm year−1 (5%–95% confidence intervals), with a central estimate of 1.6 mm year−1. This rate is on the high side, but not statistically different compared to global‐mean trends from recent reconstructions. The second question is: are there any physical processes that could explain a large deviation from the global‐mean sea‐level trend in the South Atlantic? Sterodynamic (changes in ocean dynamics and steric effects) and gravitation, rotation, and deformation effects related to ice mass loss and land water storage have probably led to a 20th‐century sea‐level trend in the South Atlantic above the global mean. Both observations and physical processes thus suggest that 20th‐century sea‐level rise in the South Atlantic has been about 0.3 mm year−1 above the rate of global‐mean sea‐level rise, although even with the additional observations, the uncertainties are still too large to distinguish a statistically significant difference. Plain Language Summary: Before the satellite era, we depend on the tide‐gauge network to measure sea‐level changes. In the North Atlantic and Pacific Oceans, many tide gauges have been installed, but there are only a handful in the South Atlantic Ocean. Because of this, it is challenging to accurately determine 20th‐century sea‐level changes in the South Atlantic. Because the South Atlantic Ocean covers about one‐fifth of the global oceans, estimates of global sea‐level changes are also affected by the low number of observations in the South Atlantic. Here, we try to improve this situation by adding recently rescued tide‐gauge observation data from Dakar and a new paleo record that has been derived from a salt marsh in the Falklands to the existing sea‐level records. We find that since 1900, South Atlantic sea level has likely risen slightly faster than the global average. This above‐average rate makes sense, because thermal expansion in the South Atlantic has likely been faster than the global mean, and mass loss from ice sheets and glaciers results in above‐average sea‐level rise in the South Atlantic. Key Points: We estimate 20th‐century sea‐level changes in the South Atlantic Ocean from tide‐gauge data and a new paleo proxy20th‐century sea‐level rise in the South Atlantic might have been above the global mean, but uncertainties remain largeEstimates of contemporary mass redistribution and sterodynamic effects support this above‐average trend [ABSTRACT FROM AUTHOR]