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Schwerpunktprogramm (SPP) 527: Bereich Infrastruktur - International Ocean Discovery Program, Teilprojekt: Periodisch auftretende 'Hyperthermals' des frühen Paläogen: Eine klimatische Besonderheit oder charakteristisches Merkmal von Treibhausklimaten?

Abrupte Erwärmungsereignisse gekoppelt an das Freisetzen von großen Mengen an Kohlendioxid in die Atmosphäre und die Ozeane treten vor allem im frühen Paläogen auf. Diese sogenannten 'Hyperthermals' zeigen viele der Eigenschaften des rezenten, menschengemachten Klimawandels, wie z.B. den schnellen Eintrag von organischem Kohlenstoff und eine rapide, globale Erwärmung. Diese Gemeinsamkeiten machen die 'Hyperthermals' zu einer häufig genutzten Analogie um die Mechanismen und Effekte von vergangenen Erwärmungsereignissen zu untersuchen und somit einen Test der vorhandenen, modellbasierten Vorhersagen durchzuführen. Weiterhin können diese Ereignisse genutzt werden, um aufzuzeigen, wie Ökosysteme mit dem schnellen Anstieg der CO2 Emissionen zurechtkommen. Neue Studien haben gezeigt, dass den periodisch wiederkehrenden 'Hyperthermals' des frühen Paläogen eine orbitale Steuerung des Kohlenstoffkreislaufes zugrunde liegt. Da dies ein zentraler Bestandteil des Klimasystems der Erde ist, sollten vergangenen Treibhausklimaten vergleichbare Mechanismen zugrunde liegen und daher 'Hyperthermals' auch in diesen auftreten. Bis zum heutigen Tag gibt es allerdings keine Studie, die das Auftreten von periodisch wiederkehrenden, orbital-gesteuerten 'Hyperthermals' außerhalb des frühen Paläogens belegt.Prinzipielle Fragestellung des vorliegenden Projektes ist daher, ob 'Hyperthermals' im Treibhausklima des Maastricht (späte Kreide) vorkommen oder nicht. Diese Frage soll durch die Erstellung von geochemischen Paläoklimaproxies für ein spezifisches Zeitintervall des Maastricht (67-68,5 Millionen Jahre) an zwei verschiedenen Kernen (IODP Site U1403 aus dem Atlantik und ODP Site 1210 aus dem Pazifik) erreicht werden. Datensätze, die im Rahmen dieses Projektes generiert werden, basieren auf der Geochemie benthischer Foraminiferen (Mg/Ca und stabile Isotope) und auf der Rekonstruktion des Karbonatgehaltes der untersuchten Sedimente unter Zuhilfenahme von wt Prozent CaCO3 Messungen und eines XRF Kernscanners. Je nach den gewonnenen Ergebnissen werden sich unterschiedlichen Erkenntnisse über die prinzipiellen Mechanismen aufzeigen, die einem Treibhausklima zugrunde liegen. Die so gewonnenen Informationen werden einen genauen Einblick in die Kontrollmechanismen von Treibhausklimaten ermöglichen und stellen darüber hinaus einen Test dar, ob 'Hyperthermals' eine gute Analogie für unser Verständnis der zukünftigen Klimaerwärmung und ihrer Auswirkungen sind. Zusätzlich werden die Daten einen Vergleich der grundlegenden Mechanismen hinter den auftretenden 'Hyperthermals' (wenn sie denn im Maastricht existieren) in zwei unterschiedlichen Treibhausklimaten erlauben: dem frühen Paläogen mit seinen bekannten 'Hyperthermals' und der späten Kreide.

DavisShip system (DShip) measurements in NetCDF format including weather station, thermosalinograph, ferrybox and navigation system gathered during Polarstern cruise PS147

The ship campaign PS147 (Atlantic Transit) with the German research vessel Polarstern took place from 12 March to 14 April 2025. The transit proceeded from Stanley, Falkland Islands, to Bremerhaven, Germany, with a stopover in Mindelo, Cape Verde, dividing the campaign into two sections, PS147/1 and PS147/2. During the voyage, several climate zones were crossed, including the Intertropical Convergence Zone (ITCZ). Here, we present data from the ship-integrated instruments within the DavisShip system (DShip), including meteorological parameters from the weather station as well as ship position and orientation from the navigation system. These data form part of a series of standardized datasets of atmospheric observations collected during the PS147 campaign.

Mean Deep Ocean volume-weighted stacks

Mean Deep Ocean stacked records weighted by ocean basin volume are also provided for: benthic δ18O, MDOT and δ18Oseawater and compiled from records described for the non-weighted stacks. The weighted stacks were created using basin weights defined using fixed deep ocean volume fractions following the volumetric approach of Lisiecki and Stern (2016) (see their Table S2), and renormalised to unity at each time step to reflect the ocean volume represented by the available records.

Atlantic, Pacific and Mean Deep Ocean temperature and δ¹⁸Oseawater stacks

Stacked deep-water (>2500m) deconvolved benthic Mg/Ca–δ18O records spanning the past 1.5 Myr for: the North Atlantic comprising IODP Site U1385 [Uvigerina peregrina and Globobulimina affinis] and DSDP Site 607 [Cibicidoides wuellerstorfi, Oridorsalis umbonatus, and Uvigerina spp.] (Sosdian and Rosenthal, 2009; Ford et al., 2016); the Pacific incorporating ODP Sites 1123 [Uvigerina spp.] (Elderfield et al., 2012) and Site 1208 [Uvigerina spp.] (Ford and Raymo, 2020); and, Mean Deep Oceans including all of the above plus ODP Site 1094 [Melonis pompilioides] (Hasenfratz et al., 2019). To investigate changes in abyssal ocean density stratification across the Middle Pleistocene Transition estimates of deep-water temperature and δ18Oseawater were generated with error propagation using PSU Solver in MATLAB (Thirumalai, Quinn and Marino, 2016). PSU Solver-derived δ18O, temperature and δ18Oseawater records for each site were interpolated on a 3 kyr interval and bootstrapped. Stacks were manually created by first identifying gaps in each site's original data and then averaging the means and errors across each age interval.

Multibeam bathymetry processed data (Atlas Hydrosweep DS 3 echo sounder entire dataset) of RV POLARSTERN during cruise PS116, Atlantic Ocean

Multibeam data were collected during RV Polarstern cruise PS116 (2018-11-11 to 2018-12-11). Multibeam sonar system was Atlas Hydrographic Hydrosweep DS 3 multibeam echo sounder. Data are processed with Caris HIPS, including sound velocity correction with SV data from SVPs, UCTDs and World Ocean Atlas 13 (https://doi.org/10.7289/v5f769gt), tidal correction with TPXO9_atlas_v5 (https://www.tpxo.net), and manual cleaning. The soundings are combined in daily files, the format is XYZ ASCII (<Lon> <Lat> <Depth in meters, positive up, relative to mean sea level>). Additional blockmedian grids have been computed with depth dependent cell size to visualize the data. These grids are not meant for scientific analysis or navigation, but for overview purposes only.

Multibeam bathymetry processed data (Atlas Hydrosweep DS 3 echo sounder entire dataset) of RV POLARSTERN during cruise PS127, Atlantic Ocean

Multibeam data were collected during RV Polarstern cruise PS127 (2021-12-04 to 2022-01-02). Multibeam sonar system was Atlas Hydrographic Hydrosweep DS 3 multibeam echo sounder. Data are processed with Caris HIPS, including sound velocity correction with SV data from SVPs, CTDs, UCTDs and World Ocean Atlas 13 (https://doi.org/10.7289/v5f769gt), tidal correction with TPXO9_atlas_v5 (https://www.tpxo.net), and manual cleaning. The soundings are combined in daily files, the format is XYZ ASCII (<Lon> <Lat> <Depth in meters, positive up, relative to mean sea level>). Additional blockmedian grids have been computed with depth dependent cell size to visualize the data. These grids are not meant for scientific analysis or navigation, but for overview purposes only.

Grenze der atlantisch/kontinentalen biogeografischen Region

Linienthema zur Darstellung der Grenze zwischen der atlantischen (Hauptnaturräume der Marsch, Unterelbe und Geest)und der kontinentalen (Naturräume des Hügellandes und der Mecklenburgischen Seenplatte sowie Vorland sowie der Mittelelbe-Niederung) biogeografischen Region für den Aufgabenbereich Natura 2000. Grundlage ist die naturräumliche Gliederung nach Meynen & Schmithüsen, hier die im Rahmen der landesweiten Biotopkartierung auf den Massstab 1:25.000 umgearbeiteten Grenzen der Naturräume. Weitere Modifizierung im Raum Geesthacht (Grenze atl. / kont. Für die Elbe pragmatisch bei Staustufe Geesthacht gesetzt)

Schwerpunktprogramm (SPP) 1294: Bereich Infrastruktur - Atmospheric and Earth system research with the 'High Altitude and Long Range Research Aircraft' (HALO), NAWDEX - North Atlantic Waveguide and Downstream Impact Experiment

The North Atlantic Waveguide and Downstream Impact Experiment (NAWDEX) aims to provide the foundation for future improvements in the prediction of high impact weather events over Europe. The concept for the field experiment emerged from the WMO THORPEX program and contributes to the World Weather Research Program WWRP in general and to the High Impact Weather (HIWeather) project in particular. An international consortium from the US, UK, France, Switzerland and Germany has applied for funding of a multi-aircraft campaign supported by enhanced surface observations, over the North Atlantic and European region. The importance of accurate weather predictions to society is increasing due to increasing vulnerability to high impact weather events, and increasing economic impacts of weather, for example in renewable energy. At the same time numerical weather prediction has undergone a revolution in recent years, with the widespread use of ensemble predictions that attempt to represent forecast uncertainty. This represents a new scientific challenge because error growth and uncertainty are largest in regions influenced by latent heat release or other diabatic processes. These regions are characterized by small-scale structures that are poorly represented by the operational observing system, but are accessible to modern airborne remote-sensing instruments. HALO will play a central role in NAWDEX due to the unique capabilities provided by its long range and advanced instrumentation. With coordinated flights over a period of days, it will be possible to sample the moist inflow of subtropical air into a cyclone, the ascent and outflow of the warm conveyor belt, and the dynamic and thermodynamic properties of the downstream ridge. NAWDEX will use the proven instrument payload from the NARVAL campaign which combines water vapor lidar and cloud radar, supplemented by dropsondes, to allow these regions to be measured with unprecedented detail and precision. HALO operations will be supported by the DLR Falcon aircraft that will be instrumented with wind lidar systems, providing synergetic measurements of dynamical structures. These measurements will allow the first closely targeted evaluation of the quality of the operational observing and analysis systems in these crucial regions for forecast error growth. They will provide detailed knowledge of the physical processes acting in these regions and especially of the mechanisms responsible for rapid error growth in mid-latitude weather systems. This will provide the foundation for a better representation of uncertainty in numerical weather predictions systems, and better (probabilistic) forecasts.

Schwerpunktprogramm (SPP) 1488: Planetary Magnetism (PlanetMag), Evolution of geomagnetic dipole moment and South Atlantic Anomaly

The geomagnetic field shields our habitat against solar wind and radiation from space. Due to the geometry of the field, the shielding in general is weakest at high latitudes. It is also anomalously weak in a region around the south Atlantic known as South Atlantic Anomaly (SAA), and the global dipole moment has been decreasing by nearly 10 percent since direct measurements of field intensity became possible in 1832. Due to our limited understanding of the geodynamo processes in Earths core, it is impossible to reliably predict the future evolution of both dipole moment and SAA over the coming decades. However, lack of magnetic field shielding as would be a consequence of further weakening of dipole moment and SAA region field intensity would cause increasing problems for modern technology, in particular satellites, which are vulnerable to radiation damage. A better understanding of the underlying processes is required to estimate the future development of magnetic field characteristics. The study of the past evolution of such characteristics based on historical, archeo- and paleomagnetic data, on time-scales of centuries to millennia, is essential to detect any recurrences and periodicities and provide new insights in dynamo processes in comparison to or in combination with numerical dynamo simulations. We propose to develop two new global spherical harmonic geomagnetic field models, spanning 1 and 10 kyrs, respectively, and designed in particular to study how long the uninterrupted decay of the dipole moment has been going on prior to 1832, and if the SAA is a recurring structure of the field.We will combine for the first time all available historical and archeomagnetic data, both directions and intensities, in a spherical harmonic model spanning the past 1000 years. Existing modelling methods will be adapted accordingly, and existing data bases will be complemented with newly published data. We will further acquire some new archeomagnetic data from the Cape Verde islands from historical times to better constrain the early evolution of the present-day SAA. In order to study the long-term field evolution and possible recurrences of similar weak field structures in this region, we will produce new paleomagnetic records from available marine sediment cores off the coasts of West Africa, Brazil and Chile. This region is weakly constrained in previous millennial scale models. Apart from our main aim to gain better insights into the previous evolution of dipole moment and SAA, the models will be used to study relations between dipole and non-dipole field contributions, hemispheric symmetries and large-scale flux patterns at the core-mantle boundary. These observational findings will provide new insights into geodynamo processes when compared with numerical dynamo simulation results.Moreover, the models can be used to estimate past geomagnetic shielding above Earths surface against solar wind and for nuclide production from galactic cosmic rays.

Dissolved major element (Ca, Sr, Mg, K, Li) concentration data of the western Atlantic Ocean meridional section GA02 (GEOTRACES) and Arctic Ocean cruise JR271 (BODC)

This dataset presents salinity-normalized dissolved major element (Ca, Mg, K, Sr, Li) concentrations in the western Atlantic Ocean and the Arctic Ocean. Atlantic samples were collected along the western meridional GEOTRACES section GA02 comprised of cruises JR057 (Punta Arenas (Chile) 02-03-2011 to Las Palmas (Spain) 06-04-2011 ), PE321 (Bermuda 11-06-2010 to Fortaleza (Brazil) 08-07-2010), PE319 (Scrabster 28-04-2010 to Bermuda 25-05-2010), and PE358 (Reykjavik (Iceland) 29-07-2012 to Texel (Netherlands) 19-08-2012). Samples for dissolved major ions were sub-sampled from trace metal sample collection stored at the Royal Netherlands Institute for Sea Research (NIOZ). Samples for the Arctic Ocean were collected on BODC cruise JR271 (Immingham 01-06-2012 to Reykjavik 02-07-2012). Samples were analysed for Na, Ca, Mg, K, Li and Sr using a Varian-720 ES ICP-OES. Samples were diluted by a factor of 78-82 in 0.12 M HCl to the same final salinity. Multiple spectral lines were selected for each element, and samples were corrected for instrumental drift by sample-standard bracketing with IAPSO P157 diluted to the same final salinity. Calibration was performed on 7 dilutions of IAPSO P157. Element-to-sodium ratios were calculated for all combinations of spectral lines. Assuming a constant Na-to-salinity (PSU)=35 ratio, the element/Na ratios were multiplied by 0.46847 µmol kg-1 to obtain the salinity (PSU)-normalized element concentration, and by the ratio of practical to absolute salinity (TEOS-10). The TEOS-10 absolute salinities were calculated from EOS-80 values using the Gibb's Oceanographic Toolbox using the R package 'gsw' (v 1.1-1).

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