dataesr/scientific-paragraphs-categorization huggingface dataset:
An extreme point with a residual higher than 60 mGal creates a characteristic bull-eye anomaly in the CBA map (Fig. 17 ). We consider similar points with extreme residuals to be erroneous, and it is therefore necessary to exclude them from the database before compiling the final CBA map. Therefore, it is necessary to choose a reasonable criterion considering the analysis of errors, as well as the problem of inhomogeneous coverage of the territory by the data described in the previous subsections. We decided to use the exclusion criterion of points exceeding interpolation residuals of ±10 mGal. A total of approx. 350 points were excluded (Fig. 18 ). Except for a few points, almost all excluded points cover marine data, which confirms the naturally lower quality of marine data.
Long-term archiving and downloads The publication and storage of the pan-Alpine gravity data and the accompanying Bouguer gravity map follows the standards of the Alliance of European Science Organisations, which has already declared its support for the long-term storage of open-access data in consideration of disciplinary regulations in the handling of research data in the "Principles for Handling Research Data" adopted in 2010 (DFG in Germany, SNSF in Switzerland, etc. ). After the completion of the AAGRG task the group is obliged for various reasons (e. g. , AAGRG "Memorandum of Collaboration" with the participating countries, long-term value of the data) to store the data permanently. GFZ Data Services (http://pmd. gfz-potsdam. de/portal/ about. htm, last access: 12 May 2021) is the cooperation partner for data publication via the special information service (FID GEO; https://www.
gfz-potsdam. de/zentrum/ bibliothek-und-informationsdienste/projekte/fid-geo/, last access: 12 May 2021). The German Research Centre for Geosciences, GFZ, the operator of GFZ Data Services, has been issuing digital object identifiers (DOI) to data sets since 2004 in accordance with the principles of the International DOI Foundation (https://www. doi. org/, last access: 12 May 2021). These data sets are archived and published by GFZ Data Services and cover the entire range of geoscientific activities. For the gravity data to be found worldwide on the Internet, the data must be given a description that is readable by search engines. This description is provided by metadata. The spe-cific description of metadata for our data set is important but is not part of this publication, but refer to general information in Appendix A.
Conclusions The aim of this publication is to report on the activities and work of the AlpArray Gravity Research Group (AAGRG) over more than 3 years. The group's mission was to recompile and release digital homogenized gravity data sets that are based on terrestrial gravity measurements that are owned by the national Alpine neighboring countries (in total more than 1 million data points). They can be used for high-resolution modeling, interdisciplinary studies from continental to regional and even to local scales, and for joint inversion with other data sets. Bouguer and free-air anomalies are available at a grid density of 4 km × 4 km for the public and of 2 km × 2 km for internal AlpArray use on request. The final products also include grids for mass and bathymetric corrections of the measured gravity at each grid point.
sities: 2670 kg m -3 for landmasses, 1030 kg m -3 for water masses above the ellipsoid and -1640 kg m -3 for those below the ellipsoid. The mass correction radius was set to Hayford zone O 2 (167 km). Special emphasis was put on the numerous lakes in the study area. They partly have a considerable effect on the gravity of stations that lie at their edges (for example, the rather deep reservoirs in the Alps). In the Ligurian Sea, ship data of the Service Hydrographique et Océanographique de la Marine and of the Bureau Gravimétrique International were implemented in the digital database. Although not unproblematic, these data got the preference over satellite data offshore. In the future, the calculation of long-distance effects of topography and bathymetry and their compensating masses (roots) are planned.
The digital recording of available terrestrial gravity data acquired by several organizations (Bureau de Recherches Géologiques et Minières, BRGM; Institut de l'Information Géographique et Forestière, IGN; oil and mining companies; universities and research institutes) was started in 1977. In 1990, BRGM founded the "Banque Gravimétrique de la France" (BGF) to manage and update the stations on the French gravity map. The BRGM database is also periodically submitted to the "International Gravimetric Bureau" (BGI) for data distribution and contribution to the global gravity mapping.
N. R. -P. F. G. , 1992) as part of the Structural Model of Italy at a scale of 1 : 500 000. The gravity values were referred to IGSN71  (Morelli et al. , 1972) , density for the terrain correction was set to 2400 kg m -3 , and the main data contribution was from the Italian National Oil Company (ENI-AGIP). In 1989 the Geological Survey of Italy, together with ENI-AGIP, published a new gravity map of Italy scaled at 1 : 1 000 000 using the data set collected for the 1 : 500 000 CNR gravity map. In the 1990s the Geological Survey of Italy undertook an extensive land gravity cartography program that has covered the whole national territory at the scale of 1 : 50 000. The presently available gravity map from the Department of Terrain defense -National Geological Survey of the "Italian Agency for Environmental Protection and Technical Services" (APAT) is a map published at the scale of 1 : 1 250 000 published in 2005  (APAT, 2005; Ferri et al.
, 2005) , which used a terrain correction density of 2670 kg m -3 and the Hayford radius of 166. 736 km. Data were collected from different sources, such as ENI, OGS, the US Defense Mapping Agency, academic organizations and the former Italian Geological Survey. Station density in the Alps for this map is about 0. 1 to 0. 2 stations per 1 km 2 , and it increases to 1. 5 stations per 1 km 2 in the basins. The Bouguer anomaly has been corrected for topography onshore, whereas for offshore a free-air anomaly map was published.
B1. 6 Germany With the start of the Deutsche Reichsaufnahme in 1934, an important development phase also began for gravity in Germany. Gravimetric maps were produced by the Amt für Bodenforschung which supplemented mainly the Alpine foreland. After 1945, the Amt für Bodenforschung coordinated the first efforts to complement this database in West Germany. Gerke (1957)  published the gravity map of West Germany (cited from  Closs, 2008). The Bouguer gravity map at a scale of 1 : 500 000 of the Federal Republic of Germany was produced by Siegfried Plaumann (e. g. , sheet south -now referred to IGSN71;  Plaumann, 1995)  on the basis of measurements by the Geophysical Survey of the Federal Republic of Germany, the Lower Saxony State Office for Soil Research, and oil companies. After corrections of the gravity meter drift and terrain, they were reduced to sea level with a density of 2670 kg m -3 and referred to IGSN71.
B1. 8 Slovak Republic A thorough overview of the practical and methodological developments of gravimetry in the Slovak Republic can be found in Understanding the Bouguer Anomaly -A Gravimetry Puzzle  (Pašteka et al. , 2017). The territory of the Slovak Republic (except the inaccessible areas of the Tatra Mountains) is covered by regional gravity measurements at the scale of 1 : 25 000 with station spacing from three to six stations per 1 km 2. The measurements were realized during a long period from the 1950s up to the 1990s. The project's goal was to create a high-definition gravity map for mineral exploration and basic geologic interpretations. Various types of gravity meters were used during the data acquisition time period (GAK PT, Worden, Canadian CG-2, Scintrex CG-3M). Different approaches to complete Bouguer anomaly (CBA) calculation were used, including different normal field formulas, different equations for "Bouguer" correction and atmospheric correction, and various methods of the terrain correction estimation.
, 1979; Schmidt, 1985; Meurers et al. , 1987; Posch and Walach, 1990; Walach, 1990; Winter, 1993). Most of the new stations were established at benchmarks of the national cadastre with maximum coordinate errors of a few tens of centimeters in height and even better accuracy in horizontal positions, even on high mountains. However, in large areas, particularly along the Alpine crest, station coverage was sparse. Since 1982, GPS techniques and helicopter transportation in otherwise inaccessible mountainous regions also made these areas accessible while meeting modern accuracy requirements. Presently the Austrian gravity database contains about 54 000 stations with an average station interval of less than 3 km even in the high mountains and average station density of one station per 9 km 2 or more.
In the early gravity campaigns Askania and Worden gravimeters were used, and since 1970 only LaCoste and Romberg or Scintrex gravimeters have been used. Depending on the data provider and acquisition date, data referred to different reference systems and exhibited different accuracy. In addition, industrial data (OMV) were tied to a gravity base which had a slightly different scale due to limited calibration accuracy. For the most recent gravity map of Austria  (Meurers and Ruess, 2009) , all data were homogenized regarding height and gravity data based on ties to the Austrian absolute gravity network  (Ruess, 2002; Meurers and Ruess, 2007). Gross coordinate errors were detected by comparing station heights with interpolations of a high-resolution digital terrain model with 50 m spacing. Erroneous coordinates were corrected by using modern topographic and orthophoto maps and by utilizing the digital cadastre  (Meurers and Ruess, 2007).
Croatia The Croatian national gravity database consists of approximately 16 500 free-air anomaly values covering the entire continental area. Data in the database were mainly collected from 1945 to 1990 across the territory of the former Socialist Federal Republic (SFR) of Yugoslavia. The data are al-most equally distributed across the wider territory of Croatia, also including some points in Bosnia and Herzegovina and Slovenia. The average point density is 1 point per 18 km 2 ; in the continental part of Croatia data density is 1 point per 8 km 2 , whereas in mountainous areas and on islands density is much lower (one station per 30 km 2 ). Each point has appended geodetic coordinates referring to GRS80 ellipsoid, whereas heights are normal-orthometric referring to the national height reference system, Croatian Height Reference System (HVRS1971).
Gravity values refer to the International Gravity System Network of 1971 (IGSN71). Metadata about the accuracy of gravity values, position and heights do not exist. Since its creation the database passed through several phases of checking, cleaning, debiasing and filtering. It was used in geophysics for creating Bouguer anomaly maps  (Bilibajkič et al. , 1979)  in the past. Most recently, it found specific usage in national geoid model determination  (Bašić, 2009; Varga, 2018). For the purposes of the AAGRG project all available points were included in the gridding of the model of Bouguer anomalies.
Czech Republic and Slovak Republic Equally for the Czech Republic and the Slovak Republic, most regional gravity surveys were conducted from the 1950s till the 1990s. The prevalent sampling interval was about 500 m, or five stations per 1 km 2 , during the so-called "mapping 1 : 25 000" scale. This mapping covered about 75 % of the Czech Republic and 100 % of the Slovakian territory, while the rest was previously covered by mapping at a 1 : 200 000 scale with about one station per 4 km 2. Principal targets of the surveys were mineral exploration for uranium, tin and other minerals, oil and gas, and hydrological and environmental investigations, as well as basic geological research. The database was reduced to a 2 km×2 km coverage and now contains 13 955 points for the Czech Republic and 21 108 points from the Slovak Republic.
In addition to the mentioned standard steps of the CBA calculation, effects of the distant topoghttps://doi. org/10. 5194/essd-13-2165-2021 Earth Syst. Sci. Data, 13, 2165 Data, 13, -2209 Data, 13, , 2021  raphy, bathymetry and ice sheet effects were calculated for the entire database. The expertise gained was fully available for the compilation of the Alpine gravity map. One of the most important steps of this process is the precise evaluation of the terrain corrections. For selected areas of Slovakia gravity maps were compiled and purpose-derived gravity maps, and density models were constructed along selected regional gravimetric profiles across the territory of the Western Carpathians. The first map in the Czech Republic was made accessible to the public in April 2009, was last updated in April 2013 and was turned into a world-wide-web format in 2014.
France Since the early 1990s, gravity densifications have been realized using Scintrex gravity meters (CG3, CG5 and currently CG6) and accurate GPS positioning, mainly as part of major scientific projects such as GéoFrance3D ("Millennium Project"). A new gravity database based on both recalculated corrections with a density of 2670 kg m -3 and on the IGSN71 system using data from the BGF and other sources  (Grandjean et al. , 1998)  was established. A new gravity map of France, including terrain corrections uniformly computed up to 166. 7 km, was released by BRGM  (Martelet et al. , 2009)  in the frame of the RCGF09 action (Gravimetric Network and Map of France 2009), which also led to the joint creation of a new gravimetric network by IGN. Since 2006, hybrid relative (Scintrex) and absolute (Micro-g A10) gravity surveys have been carried out by IGN for defining a firstorder precise gravity reference network (RMS 25 µGal) of over 1200 stations.
Nowadays, the complete gravity coverage of the French territory contains approximately 370 000 points. All this gravity information is currently used to refine the computation of the national geoid, of the gravity anomalies and of the height conversion grids. The gravity data sets over France and the surrounding marine areas are provided from the BGI global gravity databases (http://bgi. obs-mip. fr/, last access: 12 May 2021). Terrestrial data are mostly derived from the gravity surveys carried out and compiled by BRGM. They also include 2272 gravity data points in the Alps provided by IGN and other contributions from by  Guglielmetti et al. (2013)  and research laboratories (Paris, Toulouse, Montpellier, Strasbourg, Clermont-Ferrand, Grenoble and Nice). Finally, the data set has been sampled with 1 point per 4 km 2 giving a total amount of 22 593 free-air gravity values over the French territory concerned.
Offshore data Offshore gravity measurements in the study area were collected from shipborne surveys performed since the 1960s in the Gulf of Lyon and Ligurian Sea by the French IFREMER, CNEXO, SHOM and CGG. In addition, this area is also cov-ered by the extensive gravity surveys carried out between 1961 and 1972 by the Italian Experimental Geophysical Observatory over the whole Mediterranean Sea, and it is known as the "Morelli dataset"  (Allan and Morelli, 1971). These surveys were conducted with different generations of sea gravity meters (LaCoste and Romberg, Graf-Askania, Lake Constance) mounted on a gyro-stabilized platform. Corresponding gravity data and reports are archived by IFREMER and SHOM and transmitted to the BGI. Offshore gravity data included in the AlpArray compilation are provided by the GEOMED2 project  (Lequentrec-Lalancette et al.
Germany The German data used in the AlpArray project originate from three main data sets that were acquired between ca. 1930 and 2010. The AlpArray area is covered by 36 442 gravity stations. As only a few historical measurements were carried out in the frame of dense local surveys, the mean point spacing is on the order of 2 to 3 km. Regional gravity measurements were either conducted at public geodetic reference points, for which precise coordinates were available, or at prominent points that could be easily identified in maps and for which coordinates were digitized. Hence, the precision of the coordinates can vary between some centimeters and some tens of meters. The heights of the German gravity stations refer to the reference system DHHN (German main leveling network) and the version valid at the time of the measurement.
This may result in deviations from the current reference system DHHN2016 on the order of some centimeters. During the reprocessing in 2010, station heights were checked for plausibility by a comparison with heights taken from the DEM25 (the best German DEM at that time). As large deviations can also result from imprecise horizontal coordinates of the stations, such stations were additionally evaluated with respect to their location by means of GIS techniques and, if necessary, by an additional comparison with georeferenced digital topographic maps and orthophotos. For 95 % of the stations covering the entire German territory the differences in height are less than 2 m. Gravity stations that exhibit differences of more than 5 m to DEM25 were not considered in the data contribution for the compilation of the new AlpArray Bouguer gravity map.
The current Bouguer anomaly map for Germany (Leibniz-Institut für Angewandte Geophysik, 2010;  Skiba, 2011) , based on more than 275 000 data points, refers to the IGSN71 and a density of 2670 kg m -3. Absolute gravity values that were acquired in the old Potsdam gravity system were transferred to the IGSN71. The accuracy of the absolute gravity is estimated to be better than 100 µGal. For the AlpArray compilation, gravity data were provided by the Leibniz Institute for Applied Geophysics (including data from the Geophysikalische Reichsaufnahme), Kiel University and the Geological Survey of Saxony (LfULG).
Hungary Hungary contributed to the unified Bouguer gravity map with gridded data of 2 km × 2 km given in Gauß-Krüger map projection, and the terrain correction was calculated up to a distance of 22. 5 km around each station utilizing a uniform reduction density of 2670 kg m -3. The Hungarian gravity database consists of approximately 388 000 data points and covers the whole country with rather heterogeneous point density. Gravity measurements were mainly carried out between 1950 and 2010 for different purposes, which determines the point distribution. For the oil industry, local exploration grids were established with a few hundred meters grid spacing; on the other hand, due to transportation requirements, early measurements were arranged along roads. The average point density of 2. 8 points per 1 km 2 suggests a fair coverage, but it concentrates on areas with low to moderate topography.
The database consists of geodetic coordinates given in the national map projection (EOV) system with reference to the IUGG67 ellipsoid, whereas heights are given in the Baltic height system. Gravity values are tied to the Hungarian gravity network MGH (from Hungarian abbreviation), which was established, extended and readjusted in several epochs  (MGH-50, MGH-80, MGH-2000 , MGH-2010 and MGH-2013 networks; Csapó and Völgyesi, 2002; Csapó and Koppán, 2013; Csapó, 2013)  to unify gravity values, support regional-scale data processing and to connect to the Unified European Gravimetric Network. Metadata on the accuracy of horizontal position, height and gravity data are not provided in the data set. The estimated accuracy of g values is 0. 1 mGal on average. The database was collected and is maintained by the Mining and Geological Survey of Hungary.
Italy The Italian data used in the AlpArray project originate from one main data set, which is industry data handed over by ENI, and several other minor data sets, including the Province of Bolzano, newly acquired data in the Ivrea-Verbano zone preferentially to fill earlier data gaps  (Scarponi et al. , 2020) , data acquired in the Province of Bolzano during the INTA-GRAF project, and SwissTopo data. The AlpArray area is covered by 130 905 gravity stations, of which the ENI data set has 128 479 stations on land and offshore, in the Province of Bolzano there are 1737 stations, and in the Ivrea-Verbano area there are 689 stations. The data are very dense in the Po plain and scarcer at the higher elevations, with a mean point spacing of 705 m. Gravity measurements other than ENI were conducted at cadastral geodetic reference points for which precise coordinates were available or were acquired at a position and height with parallel GNSS observations.
The ENI data points were acquired with either traditional geodetic survey or the newer points with GNSS. The positions of the Italian gravity stations refer to the reference system GRS80, with the industry data having been transferred to GRS80 in the frame of a revision of the database and with the heights in normal heights. Geoidal heights were converted to ellipsoidal heights by adding the ITALGEO geoid heights. We have compared the normal heights with different terrain models, with MERIT  (Yamazaki et al. , 2017)  and in the Region Veneto with the local high-resolution DEM. The average difference with MERIT of the entire database is 0. 3 m, and the root mean square difference is 12. 63 m. The criterion for using a data point for the final map was a difference with MERIT of less than 50 m.
This large height difference is limited to relatively higher elevations outside the plains and is probably due rather to the sparse gridspacing of the MERIT model than to misplacement of the stations. We find that 66. 64 % and 79. 57 % of the entire onshore database has a height error below 5 m and below 10 m compared to MERIT, respectively. The absolute values of the ENI database referred to the old Potsdam gravity system and were transferred to the IGSN71, correcting the values for 14. 00 mGal  (Morelli, 1948; Wollard, 1979). In the areas with both ENI data and modern acquired data, the systematic shift was confirmed by direct comparison of the absolute gravity values.
Switzerland The Swiss gravity database GRAVI-CH was collected and maintained by the University of Lausanne  (Olivier et al. , 2010). It consists of around 30 000 points with measurements from 1953 to 2000. The data set used in this project is a subset of 7962 points from GRAVI-CH, limited to the area of Switzerland and Liechtenstein and reduced to a density of 1 point per 2 km × 2 km point density extraction. Many of the Swiss gravity points have been measured on geodetic reference points. Their position accuracy is a few centimeters in the Swiss projection system LV03. The positions of the other points have just been read from topographic maps at a scale of 1 : 25 000. Their accuracy in position is on the order of 10-20 m. All the data have been transformed to ETRS89 using the official method of the Federal Office of Topography.
C1  and statistical findings in Table  C2. Several points exceeding the threshold of ±50 m of difference between the measured and interpolated height were separately assessed and subsequently excluded from the database. The biggest differences are in Slovenia and the mountainous parts of France most likely due to the poor quality of station positions in old gravity data. Figure  C2  presents the frequency distribution of the height residuals for the data sets of all contributing countries. For the calculation of MC within the middle zone (250-5240 m) it is very suitable to use DEMs with medium resolution (1-3 arcsec) which uniformly cover the whole territory, have the same shape representation and accuracy, and can be converted with local geoid and quasi-geoid models to ellipsoidal heights.