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Author Topic: Supporting Paleo-Evidence/Calibration for WAIS Collapse Hazard Scenarios  (Read 82935 times)

AbruptSLR

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Re: Supporting Paleo-Evidence/Calibration for WAIS Collapse Hazard Scenarios
« Reply #200 on: August 13, 2017, 04:40:24 AM »
The Younger Dryas cooling, in the Northern Hemisphere, began while the Antarctic Cold Reversal (ACR) was still ongoing, and the ACR ended in the midst of the Younger Dryas. Blunier, Thomas; et al., "Phase Lag of Antarctic and Greenland Temperature in the last Glacial...," in Abrantes, Fatima; Mix, Alan C., eds. (1999). Reconstructing Ocean History: A Window into the Future. New York: Kluwer Academic. ISBN 0-306-46293-1., pp. 121–138.

The GCM (Image 2) interestingly shows freezing conditions in estuaries of the Equatorial rivers (the Amazon and the Congo) while GCM delivers overall warming for SH and tropics. It is assumed from YD images 1 and 2 that the ACR had ended and thus SH SST had largely increased, but isolated pockets of cold existed because there were grounded ice bergs that were still melting - or SH GCM model is overstating the SH warmth and more of it was cooler.

Notable exceptions to overall SH warmth (image 2) are the large cold regions (i.e. the Chilean Coast of South America and Western and Southern Shores of Australia). It is here proposed that GCM probably overstates the SH warming, or there were significant persistent pile ups of ice bergs along the coast lines of South America (i.e. the Amazon cold anomaly), or the Western Equatorial Africa (i.e. the Congo anomaly). The failure of Ross Ice Shelf would be behind the Chilean cold anomaly, the Brazilian coastal anomaly (i.e. the Amazon cold spot), the Equatorial African anomaly (i.e. the Congo cold spot) and the failure of the Ronne Ice Shelf and other Antarctic shelves were behind the ice pile up on the southern and western shores of Australia.

The rapid cooling within one summer season is indicative of ice sheet / melt water lake collapse to cool the Northern Atlantic Ocean and its associated climate just within few weeks (Image 3). Teleconnections of such rapid cooling of ocean require large ice volume dumping which should have rapidly increased the sea level projecting a tongue of water beneath continental ice shelves world wide and making them to calve rapidly on both hemispheres due to a bending effect. German sea level fears may be well placed and correct in seeing coastal nuclear reactors as risk.


Thanks.

If one thinks of the cool/negative phase of the AMO as a minor representation of a Younger Dryas event; then the linked reference indicates that when the AMO is in a negative phase, this research would indicate that for the next two, or more, decades we can expect the tropical Pacific Ocean to be warmer than normal; i.e. that El Nino events will be more frequent and more intense, which particularly warms Antarctica and which indicates that for this period the GMSTA may well be above its average trend line:

KEWEI LYU, JIN-YI YU, AND HOUK PAEK (2017), "The Influences of the Atlantic Multidecadal Oscillation on the Mean Strength of the North Pacific Subtropical High during Boreal Winter", Journal of Climate, https://doi.org/10.1175/JCLI-D-16-0525.1

http://journals.ametsoc.org/doi/10.1175/JCLI-D-16-0525.1
&
https://www.ess.uci.edu/~yu/PDF/Lyu-Yu-Paek.JCLI.2017.pdf

Abstract: "The Atlantic multidecadal oscillation (AMO) has been shown to be capable of exerting significant influences on the Pacific climate. In this study, the authors analyze reanalysis datasets and conduct forced and coupled experiments with an atmospheric general circulation model (AGCM) to explain why the winter North Pacific subtropical high strengthens and expands northwestward during the positive phase of the AMO. The results show that the tropical Atlantic warming associated with the positive AMO phase leads to a westward displacement of the Pacific Walker circulation and a cooling of the tropical Pacific Ocean, thereby inducing anomalous descending motion over the central tropical Pacific. The descending motion then excites a stationary Rossby wave pattern that extends northward to produce a nearly barotropic anticyclone over the North Pacific. A diagnosis based on the quasigeostrophic vertical velocity equation reveals that the stationary wave pattern also results in enhanced subsidence over the northeastern Pacific via the anomalous advections of vorticity and temperature. The anomalous barotropic anticyclone and the enhanced subsidence are the two mechanisms that increase the sea level pressure over the North Pacific. The latter mechanism occurs to the southeast of the former one and thus is more influential in the subtropical high region. Both mechanisms can be produced in forced and coupled AGCMs but are displaced northward as a result of stationary wave patterns that differ from those observed. This explains why the model-simulated North Pacific sea level pressure responses to the AMO tend to be biased northward."
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