A Three-Dimensional Model of the Marine Nitrogen Cycle during the Last Glacial Maximum Constrained by Sedimentary Isotopes

A quasi-three-dimensional (3-D) climate model (Sellers, 1983) was used to simulate the climate of the Last Glacial Maximum (LGM) in order to provide climatic input for the modelling of the Northern Hemisphere ice sheets. The climate model is basically a coarse-gridded general circulation (GCM) with simplified dynamics, and was subject to appropriate boundary conditions for ice-sheet elevation, atmospheric CO2concentration and orbital parameters. When compared with the present-daysimulation, the simulated climate at the Last Glacial Maximum is characterized by a global annual cooling of 3.5°C and a reduction in global annualprecipitation of 7.5%, which agrees well with results from other, more complex GCMs. Also the patterns of temperature change compare fairly with mostother GCM results, except for a smaller cooling over the North Atlantic and the larger cooling predicted for the summer rather than for the winter over Eurasia.The climate model is able to simulate changes in Northern Hemisphere tropospheric circulation, yielding enhanced westerlies in the vicinity of the Laurentide and Eurasian ice sheets. However, the simulated precipitation patterns are less convincing, and show a distinct mean precipitation increase over the Laurentide ice sheet. Nevertheless, when using the mean-monthly fields of LGM minus present-day anomalies of temperature and precipitation rate to drive a three-dimensional thermomechanical ice-sheet model, it was demonstrated that within realistic bounds of the ice-flow and mass-balance parameters, veryreasonable reconstructions of the Last Glacial Maximum ice sheets could be obtained.

Download Full-text

Atmospheric Local Energetics and Energy Interactions between Mean and Eddy Fields. Part II: An Example for the Last Glacial Maximum Climate

Journal of the Atmospheric Sciences ◽

10.1175/2010jas3583.1 ◽

2011 ◽

Vol 68 (3) ◽

pp. 533-552 ◽

Cited By ~ 7

Author(s):

Shigenori Murakami ◽

Rumi Ohgaito ◽

Ayako Abe-Ouchi

Keyword(s):

Last Glacial Maximum ◽

Three Dimensional ◽

Complete Information ◽

Glacial Maximum ◽

Dimensional Structure ◽

Atlantic Sector ◽

Last Glacial ◽

Energy Cycle ◽

The Last Glacial Maximum ◽

The Last Glacial

Abstract The atmospheric local energy cycle in the Last Glacial Maximum (LGM) climate simulated by an atmosphere–ocean GCM (AOGCM) is investigated using a new diagnostic scheme. In contrast to existing ones, this scheme can represent the local features of the Lorenz energy cycle correctly, and it provides the complete information about the three-dimensional structure of the energy interactions between mean and eddy fields. The diagnosis reveals a significant enhancement of the energy interactions through the barotropic processes in the Atlantic sector at the LGM. Energy interactions through the baroclinic processes are also enhanced in the Atlantic sector, although those in the Pacific sector are rather weakened. These LGM responses, however, are not evident in the global energy cycle except for an enhancement of the energy flow through the stationary eddies.

Download Full-text

A three-dimensional climate—ice-sheet model applied to the Last Glacial Maximum

Annals of Glaciology ◽

10.3189/s0260305500014245 ◽

1997 ◽

Vol 25 ◽

pp. 333-339 ◽

Cited By ~ 12

Author(s):

Philippe Huybrechts ◽

Stephen T’siobbel

Keyword(s):

Last Glacial Maximum ◽

Northern Hemisphere ◽

Climate Model ◽

Three Dimensional ◽

Ice Sheets ◽

Ice Sheet ◽

Glacial Maximum ◽

Last Glacial ◽

The Last Glacial Maximum ◽

The Last Glacial

A quasi-three-dimensional (3-D) climate model (Sellers, 1983) was used to simulate the climate of the Last Glacial Maximum (LGM) in order to provide climatic input for the modelling of the Northern Hemisphere ice sheets. The climate model is basically a coarse-gridded general circulation (GCM) with simplified dynamics, and was subject to appropriate boundary conditions for ice-sheet elevation, atmospheric CO2 concentration and orbital parameters. When compared with the present-daysimulation, the simulated climate at the Last Glacial Maximum is characterized by a global annual cooling of 3.5°C and a reduction in global annualprecipitation of 7.5%, which agrees well with results from other, more complex GCMs. Also the patterns of temperature change compare fairly with mostother GCM results, except for a smaller cooling over the North Atlantic and the larger cooling predicted for the summer rather than for the winter over Eurasia.The climate model is able to simulate changes in Northern Hemisphere tropospheric circulation, yielding enhanced westerlies in the vicinity of the Laurentide and Eurasian ice sheets. However, the simulated precipitation patterns are less convincing, and show a distinct mean precipitation increase over the Laurentide ice sheet. Nevertheless, when using the mean-monthly fields of LGM minus present-day anomalies of temperature and precipitation rate to drive a three-dimensional thermomechanical ice-sheet model, it was demonstrated that within realistic bounds of the ice-flow and mass-balance parameters, veryreasonable reconstructions of the Last Glacial Maximum ice sheets could be obtained.

Download Full-text

Continental/Cordilleran ice interactions: a dominant cause of westward super-elevation of the last glacial maximum continental ice limit in southwestern Alberta, Canada

CrossRef Listing of Deleted DOIs ◽

10.1080/030094801300062284 ◽

2001 ◽

Vol 30 (1) ◽

pp. 43-52 ◽

Cited By ~ 4

Author(s):

Edward C. Little ◽

Lionel E. Jackson ◽

Thomas S. James ◽

Stephen R. Hicock ◽

Elizabeth R. Leboe

Keyword(s):

Last Glacial Maximum ◽

Glacial Maximum ◽

Last Glacial ◽

The Last Glacial Maximum ◽

The Last Glacial

Download Full-text

Mollusk record of millennial climate variability in the Loess Plateau during the Last Glacial Maximum

Boreas ◽

10.1080/03009480210648 ◽

2002 ◽

Vol 31 (1) ◽

pp. 20-27 ◽

Cited By ~ 31

Author(s):

Naiqin Wu ◽

Tungsheng Liu ◽

Xiuping Liu ◽

Zhaoyan Gu

Keyword(s):

Climate Variability ◽

Last Glacial Maximum ◽

Loess Plateau ◽

Glacial Maximum ◽

The Loess Plateau ◽

Last Glacial ◽

The Last Glacial Maximum ◽

The Last Glacial

Download Full-text

Reconstructions of the past distribution of Testudo graeca mitochondrial lineages in the Middle East and Transcaucasia support multiple refugia since the Last Glacial Maximum

Herpetological Journal ◽

10.33256/31.1.1017 ◽

2021 ◽

pp. 10-17

Author(s):

Oguz Turkozan

Keyword(s):

Middle East ◽

Last Glacial Maximum ◽

Glacial Maximum ◽

Testudo Graeca ◽

Last Glacial ◽

The Past ◽

Precipitation Seasonality ◽

Multiple Refugia ◽

The Last Glacial Maximum ◽

The Last Glacial

A cycle of glacial and interglacial periods in the Quaternary caused species’ ranges to expand and contract in response to climatic and environmental changes. During interglacial periods, many species expanded their distribution ranges from refugia into higher elevations and latitudes. In the present work, we projected the responses of the five lineages of Testudo graeca in the Middle East and Transcaucasia as the climate shifted from the Last Glacial Maximum (LGM, Mid – Holocene), to the present. Under the past LGM and Mid-Holocene bioclimatic conditions, models predicted relatively more suitable habitats for some of the lineages. The most significant bioclimatic variables in predicting the present and past potential distribution of clades are the precipitation of the warmest quarter for T. g. armeniaca (95.8 %), precipitation seasonality for T. g. buxtoni (85.0 %), minimum temperature of the coldest month for T. g. ibera (75.4 %), precipitation of the coldest quarter for T. g. terrestris (34.1 %), and the mean temperature of the driest quarter for T. g. zarudyni (88.8 %). Since the LGM, we hypothesise that the ranges of lineages have either expanded (T. g. ibera), contracted (T. g. zarudnyi) or remained stable (T. g. terrestris), and for other two taxa (T. g. armeniaca and T. g. buxtoni) the pattern remains unclear. Our analysis predicts multiple refugia for Testudo during the LGM and supports previous hypotheses about high lineage richness in Anatolia resulting from secondary contact.

Download Full-text