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Last interglacial seasonal hydroclimate in the North Sea–Baltic Sea region

Ni, S. LU ; Lu, Z. LU ; Zhang, Q. LU ; Groeneveld, J. ; Knudsen, Karen Luise ; Seidenkrantz, M. S. and Filipsson, H. L. LU orcid (2023) In Quaternary Science Reviews 312.
Abstract

The Last Interglacial (LIG) experienced substantial changes in seasonal insolation compared with the present day, which may have affected the hydrography and water-mass exchange in the North Sea and Baltic Sea region. Here we investigate the effects of solar radiation and greenhouse gas (GHG) forcing on the regional climate by analyzing model simulations of the LIG (127 ka BP), pre-industrial (PI, 1850 CE), and present-day (PD, 1990 CE) climates. We also interpret the reconstructed seasonal bottom water conditions using benthic foraminifera and geochemistry data. Our simulations reveal that during the LIG, the Baltic Sea region (including the Kattegat and the Danish Straits) experienced more saline and colder bottom waters than those in... (More)

The Last Interglacial (LIG) experienced substantial changes in seasonal insolation compared with the present day, which may have affected the hydrography and water-mass exchange in the North Sea and Baltic Sea region. Here we investigate the effects of solar radiation and greenhouse gas (GHG) forcing on the regional climate by analyzing model simulations of the LIG (127 ka BP), pre-industrial (PI, 1850 CE), and present-day (PD, 1990 CE) climates. We also interpret the reconstructed seasonal bottom water conditions using benthic foraminifera and geochemistry data. Our simulations reveal that during the LIG, the Baltic Sea region (including the Kattegat and the Danish Straits) experienced more saline and colder bottom waters than those in the PD, in agreement with the reconstruction data. This can be attributed to lower GHG levels and enhanced water exchange of cooler, saline North Sea water into the Baltic Sea during the LIG. The thermocline was stronger during the summer months in the LIG, mainly due to the higher sea surface temperature (SST) compared to that of the PD resulting from increased summer insolation. Further, the temperature anomalies (LIG–PD) show significant inverse correlations with the precipitation–minus–evaporation (P–E) at the Baltic Sea entrance. However, the P–E balance appears to have had minimal impact on salinity changes in the North Sea, the Baltic Proper, and the open sea area. Our findings indicate that monthly surface and bottom water salinity anomalies of LIG-PI exhibit strong positive correlations with the North Atlantic Oscillation (NAO) anomalies in the Baltic entrance region. During the LIG, a more positive phase of the NAO index in autumn played a crucial role in wind-driven major inflows and led to more intensive water exchange in the North Sea–Baltic Sea region compared to the late Holocene.

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organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Baltic Sea, Data-model comparison, EC-Earth model, Evaporation, Greenhouse Gas (GHG), Hydrography, Insolation, North Atlantic Oscillation (NAO), Paleoceanography, Precipitation, Salinity, Seasonality, Temperature, The Last Interglacial
in
Quaternary Science Reviews
volume
312
article number
108152
publisher
Elsevier
external identifiers
  • scopus:85162142408
ISSN
0277-3791
DOI
10.1016/j.quascirev.2023.108152
project
MERGE SP: Proxy-based reconstructions and model simulations of seasonal climate variations during the Last Interglacial in the Baltic Sea
Tracing hypoxia during warm periods in the Baltic Sea region - using synchrotron X-ray spectroscopy and plasma analytical methods
language
English
LU publication?
yes
additional info
Funding Information: We thank the strategic research area MERGE (Modeling the Regional and Global Earth system) at the Centre for Environmental and Climate Research ( CEC ), Lund University for funding. We acknowledge support from the Swedish Research Council ( 2022-03129 ). Simulations with EC–Earth were performed on resources provided by the Swedish National Infrastructure for Computing ( SNIC ) at the National Supercomputer Centre (NSC) partially funded by the Swedish Research Council through grant agreement no. 2022-06725 and no. 2018-05973. The SMHI hydrographic data collection is organized by the environmental monitoring program and funded by the SwAM. We also acknowledge the Independent Research Fund Denmark (grant no. 0135–00165B (GreenShelf) to MSS); the project has also received funding from the European Union's Horizon 2020 research and innovation program under grant agreement no. 869383 (ECOTIP) (MSS). Publisher Copyright: © 2023 The Authors
id
1120332c-6aa0-4a99-b71d-ea32a326f597
date added to LUP
2023-08-06 19:30:15
date last changed
2023-08-15 14:49:43
@article{1120332c-6aa0-4a99-b71d-ea32a326f597,
  abstract     = {{<p>The Last Interglacial (LIG) experienced substantial changes in seasonal insolation compared with the present day, which may have affected the hydrography and water-mass exchange in the North Sea and Baltic Sea region. Here we investigate the effects of solar radiation and greenhouse gas (GHG) forcing on the regional climate by analyzing model simulations of the LIG (127 ka BP), pre-industrial (PI, 1850 CE), and present-day (PD, 1990 CE) climates. We also interpret the reconstructed seasonal bottom water conditions using benthic foraminifera and geochemistry data. Our simulations reveal that during the LIG, the Baltic Sea region (including the Kattegat and the Danish Straits) experienced more saline and colder bottom waters than those in the PD, in agreement with the reconstruction data. This can be attributed to lower GHG levels and enhanced water exchange of cooler, saline North Sea water into the Baltic Sea during the LIG. The thermocline was stronger during the summer months in the LIG, mainly due to the higher sea surface temperature (SST) compared to that of the PD resulting from increased summer insolation. Further, the temperature anomalies (LIG–PD) show significant inverse correlations with the precipitation–minus–evaporation (P–E) at the Baltic Sea entrance. However, the P–E balance appears to have had minimal impact on salinity changes in the North Sea, the Baltic Proper, and the open sea area. Our findings indicate that monthly surface and bottom water salinity anomalies of LIG-PI exhibit strong positive correlations with the North Atlantic Oscillation (NAO) anomalies in the Baltic entrance region. During the LIG, a more positive phase of the NAO index in autumn played a crucial role in wind-driven major inflows and led to more intensive water exchange in the North Sea–Baltic Sea region compared to the late Holocene.</p>}},
  author       = {{Ni, S. and Lu, Z. and Zhang, Q. and Groeneveld, J. and Knudsen, Karen Luise and Seidenkrantz, M. S. and Filipsson, H. L.}},
  issn         = {{0277-3791}},
  keywords     = {{Baltic Sea; Data-model comparison; EC-Earth model; Evaporation; Greenhouse Gas (GHG); Hydrography; Insolation; North Atlantic Oscillation (NAO); Paleoceanography; Precipitation; Salinity; Seasonality; Temperature; The Last Interglacial}},
  language     = {{eng}},
  month        = {{07}},
  publisher    = {{Elsevier}},
  series       = {{Quaternary Science Reviews}},
  title        = {{Last interglacial seasonal hydroclimate in the North Sea–Baltic Sea region}},
  url          = {{http://dx.doi.org/10.1016/j.quascirev.2023.108152}},
  doi          = {{10.1016/j.quascirev.2023.108152}},
  volume       = {{312}},
  year         = {{2023}},
}