A first Alps - dedicated gravity data set - introduction and status of the AlpArray gravity field activities

In this contribution, activities of the AlpArray Gravity Research Group (AAGRG) are introduced. Since 2018, this group in the frame of the AlpArray project (http://www.alparray.ethz.ch/en/home/) prepares gravity and other data sets to support multidisciplinary goals of the project. It is focused on the mantle, plate and surface processes in the Alps-Apennines-Carpathians-Dinarides orogenic system. In 2018, the AAGRG set up its own methodology guidelines and assembled available land-gravity data and digital elevation model (DEM) data from all the participating countries. Our presentation targets especially three goals: 1) to introduce AAGRG activities as an integral part of the AlpArray project for studying Alpine orogeny \u2013 a goal that by definition requires international cooperation, 2) to review the input data and the works accomplished so far, and, 3) to discuss the steps to be taken to produce detailed gravity maps of the region \u2013 the first Alps-dedicated gravity field data set. We plan to prepare gravity grids in a homogeneous processing approach of either 2x2 km or 4x4 km resolution, depending on the coverage and data quality. The final data sets will be made public in late 2019. A special emphasis is put on the calculation of the Bouguer anomaly using ellipsoidal rather tha normal heights. For calculating topographic effects the preference is given to local DEMs, where available, as they often provide higher quality and spatial resolutions. The public gravity data sets are evaluated with the high-resolution geopotential models like EIGEN-6C4 or EGM2008 \u2013 a useful means for identifying biases in the data coming from various countries and campaigns

Structure-activity relationships of the N-methylcarbamate series in Salmonella typhimurium.

Aromatic hydrocarbons of low molecular weight, hydroxy and N-methylcarbamate derivatives were tested for mutagenicity by the reversion of histidine-dependent Salmonella typhimurium TA98 and TA1535 in the presence of a rat-liver 9000 × g supernatant fraction. The presence of 2 or 3 aromatic rings resulted in a weak increase in revertants. Hydroxylation and carbamylation of aromatic rings increased the mutagenic activity of these aromatic compounds. In order to evaluate the structure-activity relationship, the specific molecular connectivity indices were calculated. A significant inverse relationship exist between mutagenicity and zero- and second-order specific molecular connectivity indices. Only compounds with second-order specific molecular connectivity indices lower than 0.300 increased mutagenic activity

A new land \u2013 based gravity data set for the Alps and adjacent regions \u2013 the AAGRG at work

A pan-Alpine gravity data map, homogeneous regarding input data sets, applied methods and corrections as well ascommon reference frames, is not available yet. Therefore, all countries around the Alps have agreed to contributewith gravity data and/or gravity data processing techniques to a recompilation of the alpine gravity field in theframe of the AlpArray Gravity Research Group (AAGRG). Also to collaborate with other groups in AlpArray.In the last year group members met two times to set up guidelines for joint processing and homogenizationof existing gravity data sets. Following the results and appointments of the last technical AAGRG meeting inBratislava October 2018, the members of the 9 participating countries decided to present a first data set of theBouguer gravity field in September 2019 on a 2km x 2km or 4km x 4km grid for the public. Other compilationswill follow: maps of Free Air Gravity, regional field and the corresponding residual gravity field. These new datasets will be available to all AlpArray partners for interdisciplinary work and modelling.This new Bouguer anomaly will be station completed with at least 1 point/4 km2 resolution and compiledaccording to the most modern criteria. In general, even though global models like SRTM1 perform well, thepreference was given to local DEMs - if available. Two software packages for topographic corrections on thebase of ellipsoidal heights are available: \u201cTOPOSK\u201d, developed by Slovak colleagues, and the \u201cadaptive masscorrection\u201d from the Kiel group. The results of both methods are being tested and compared. The geophysicalindirect effect and its determination are also taken into account. Special emphasis is put on the lakes in the studyarea. They have a considerable effect on the gravity of stations that lie at their edges (for example, the partiallyvery deep reservoirs in the Alps). In the Ligurian and the Adriatic seas ship data of the Bureau Gravim\ue9triqueIinternational will be used. Although not unproblematic, these data got the preference over satellite data.In the AAGRG, long discussions were centered on the calculation of long-distance effects of topogra-phy/bathymetry and its compensating masses (root). The first compilation of the AA Bouguer anomaly mapwill, however, be prepared WITHOUT taking long-distance effects in account. The group agreed to extendthe correction radius to the Hayford zone O2(167 km). All topographic corrections will be calculated as masscorrections between the physical surface and the ellipsoidal reference. The group further discussed the necessityof a 3D interpolation of the gravity grid values. Although a 3D interpolation would be required from themethodological-theoretical point of view (the problem is the non-identical gravity and height grids), it was decidedto perform a 2D interpolation in the first compilation - the method of Kriging shall be applied. The poster will visualize the mentioned correction effects and illuminate the necessity of a complete revision of the existing land based Alpine gravity data

Relative Gravity Measurement Campaign during the 7th International Comparison of Absolute Gravimeters (2005)

Since the 1st International Comparison of Absolute Gravimeters (ICAG) and accompanying Relative Gravity Campaign (RGC) held at the BIPM in 1981, repeated ICAG-RGCs have been organized every four years. A total of 19 absolute gravimeters (AG) and 15 relative gravimeters (RG) participated in the 7th ICAG-RGC, which took place in 2005. Co-located absolute and relative gravity measurements as well as precision levelling measurements were carried out. The final version of the absolute g values of the 7th ICAG has been officially released recently. This paper is the final report of the 7th RGC and replaces the preliminary results published earlier. It covers the organization of the RGC and the data processing, analyses RG behaviour, computes g, delta g and O(AG) (offset of AG) and discusses their uncertainties. In preparation for the BIPM key comparison ICAG-2009, a standard data- processing procedure has been developed and installed in the BIPM ICAG-RGC software package, GraviSoft. This was used for the final data processing

Results of the Sixth International Comparison of Absolute Gravimeters, ICAG-2001

The Sixth International Comparison of Absolute Gravimeters was held from 5 June to 28 August 2001 at the Bureau International des Poids et Mesures (BIPM), Sevres. Seventeen absolute gravimeters were used to make measurements at five sites of the BIPM gravity network. The vertical gravity gradients at the sites and the ties between them were also measured using seventeen relative gravimeters. For the first time the ties were also measured using absolute gravimeters. Various methods of processing the absolute and relative data were tested to calculate the results. The final results of ICAG-2001 are presented. The acceleration due to gravity at a height of 0.90 m is given as (980925701.2 ± 5.5) Gal and (980928018.8 ± 5.5) Gal for sites A and B, respectively, calculated using a combined adjustment of the absolute and relative data

Results of the Sixth International Comparison of Absolute Gravimeters, ICAG-2001

The Sixth International Comparison of Absolute Gravimeters was held from 5 June to 28 August 2001 at the Bureau International des Poids et Mesures (BIPM), Sevres. Seventeen absolute gravimeters were used to make measurements at five sites of the BIPM gravity network. The vertical gravity gradients at the sites and the ties between them were also measured using seventeen relative gravimeters. For the first time the ties were also measured using absolute gravimeters. Various methods of processing the absolute and relative data were tested to calculate the results. The final results of ICAG-2001 are presented. The acceleration due to gravity at a height of 0.90 m is given as (980 925 701.2 +/- 5.5) muGal* and (980 928 018.8 5.5) LGal for sites A and B, respectively, calculated using a combined adjustment of the absolute and relative data