Mathematics – Logic
Scientific paper
Dec 2001
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2001agufmpp31b..02s&link_type=abstract
American Geophysical Union, Fall Meeting 2001, abstract #PP31B-02
Mathematics
Logic
1600 Global Change, 1620 Climate Dynamics (3309), 1635 Oceans (4203)
Scientific paper
The nature and magnitude of climatic variability during the period of middle Pliocene warmth between (ca 3.29 to 2.97 Ma) is poorly understood. This period in earth's history is interesting because it spans the transition from relatively warm global climates, when glaciers were absent, or greatly reduced in the Northern Hemisphere, to the generally cooler climates of the Pleistocene. We present a suite of palaeoclimate modelling experiments incorporating an advanced atmospheric GCM, coupled to a Q-flux ocean model for 3.29, 3.12 and 2.97 Ma BP. Astronomical solutions for the periods in question were derived from the Berger and Loutre BL2 astronomical solution. Boundary conditions, excluding SSTs which were predicted by the slab ocean model, were provided from the USGS PRISM2 digital data set. The model results indicate that little annual variation (>0.5 degrees C) in SSTs, relative to a "control" experiment, occurred during the middle Pliocene in response to the altered orbital configurations. Annual surface air temperatures also displayed little variation. Seasonally, surface air temperatures displayed a trend of cooler temperatures during December, January and February, and warmer temperatures during June, July and August. This pattern is consistent with altered seasonality resulting from the prescribed orbital configurations. Precipitation changes follow the seasonal trend observed for surface air temperature. Relative to present-day, surface wind strength and wind stress over the North Atlantic, North Pacific and Southern Ocean remained greater in each of the Pliocene experiments. This suggests that wind driven gyral circulation may have been consistently greater during the middle Pliocene. The magnitude of climatic variability predicted by the GCM for the middle Pliocene is almost certainly an underestimate. This assertion is supported by geological proxy climate data. This underestimate is derived from, (a) the relative insensitivity of the GCM to perturbation in imposed boundary conditions, (b) a lack of detailed time series data concerning changes to terrestrial ice cover and greenhouse gas concentrations for the middle Pliocene and (c) difficulties in representing the effects of 'climatic history' in snap-shot GCM experiments.
Haywood Alan M.
Sellwood B. W.
Valdes Paul J.
No associations
LandOfFree
Magnitude of Climate Variability During Middle Pliocene Warmth: A Palaeoclimate Modelling Study does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Magnitude of Climate Variability During Middle Pliocene Warmth: A Palaeoclimate Modelling Study, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Magnitude of Climate Variability During Middle Pliocene Warmth: A Palaeoclimate Modelling Study will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1378469