Sentences with phrase «gia modelling»

Konfal, S. A., Wilson, T. J., Bevis, M. G., Kendrick, E. C., Dalziel, I. W., Smalley, R., Willis, M. J., Heeszel, D. S., Wiens, D. A., (2014), GPS Measurements of Crustal Motion Indicate 3D GIA Models are Needed to Understand Antarctic Ice Mass Change, Abstract G51A - 0342, presented at 2014 Fall Meeting, AGU, San Francisco, Calif..

The GRACE estimates for Antarctica used in that study were not our own and were based on a mean of W12a and an alternative new GIA model.

Both studies highlight the need for further improvements to Antarctic GIA models, however.

Despite the better fit to observations in our GIA model, significant uncertainties remain.

The GRACE - Tellus mass grids described elsewhere in this website have had a reasonable GIA model of secular trends removed, in terms of mass changes expressed as cm of equivalent water thickness per year....

One is based on a model of Glacial Isostatic Adjustment (GIA model based), another uses GPS estimates (GPS based).»]

This meant early GIA models had grossly overestimated the weight of past glaciers and the subsequent rebound.

To remove bias in GIA models, our best method requires comparing Global Positioning System data (GPS) that measures the current bedrock uplift with GIA modeled predictions.

Most GIA models assume Antarctica has been rebounding upwards since deglaciation removed the weight of glacial ice.

Zwally argues that current GIA models should be lowered by just 1.6 mm / year and that small adjustment would bring the estimates based on GRACE data into agreement with Zwally's elevation data.

By adjusting the de-glaciation history, Whitehouse 2012 revised their GIA model so that the upward bias was reduced to 1.2 mm / year with error estimates of 2.3 mm / year.

Similarly other Zwally detractors pointed to papers such as Harig 2015 that claimed Antarctica was losing ice, but Harig 2015 used GIA models that were well known to over-estimate glacial rebound.

There is more evidence to support Zwallys critique of GIA models.

However along the coast wherever GPS measurements have been possible, research revealed GIA models had biased the uplift upwards by 4.9 to 5.0 mm / years relative to GPS observations.

The global mean sea level trend is corrected for the Glacial Isostatic Adjustment using the ICE5G - VM2 GIA model (Peltier, 2004) to take into account the associated volume changes of the ocean.

Not exact matches

``... The inferred GIA signal over the complete Antarctic continent supports Late - Pleistocene ice models derived from glacio - geologic studies, with important differences over the two main ice - shelves.

Land motions related to GIA can be simulated in global geodynamic models.

The right panel shows the predicted GIA signal from our new model.

With a much - needed GRACE follow - on mission being planned and expected to launch around 2017, observation and modelling of Antarctic GIA will continue to give us insights into the ice sheet history — from the LGM through to the present — and hence provide the context for any future changes.

The GRACE observations over Antarctica suggest a near - zero change due to combined ice and solid earth mass redistribution; the magnitude of our GIA correction is substantially smaller than previous models have suggested and hence we produce a systematically lower estimate of ice mass change from GRACE data: we estimate that Antarctica has lost 69 ± 18 Gigatonnes per year (Gt / yr) into the oceans over 2002 - 2010 — equivalent to +0.19 mm / yr globally - averaged sea level change, or about 6 % of the sea - level change during that period.

Some groups have tried to develop models of the rebounding land, so that sea level researchers can apply «Glacial Isostatic Adjustments» (GIA) to their data to correct for the effects.

In the real world data, trumps models, especially those with GIA adjustments.

We demonstrate that the combination of lower estimates of the 20th century GMSL rise (up to 1990) improved modeling of the GIA process and that the correction of the eclipse record for a signal due to angular momentum exchange between the fluid outer core and the mantle reconciles all three Earth rotation observations.

A study by Mitrovica et al. (2015) has demonstrated that the combination of lower estimates of the GMSL rise between 1900 and 1990 (~ 1.2 mm yr - 1), improved modeling of the GIA process and the signal due to core - mantle coupling in ancient eclipse observations resolves «Munk's enigma.»

Statistically significant trends obtained from records longer than 40 years yielded sea - level - rise estimates between 1.06 — 1.75 mm / yrear - 1, with a regional average of 1.29 mm yr - 1, when corrected for global isostatic adjustment (GIA) using model data, with a regional average of 1.29 mm - 1..

And after diff GPS observational GIA became available for Antarctica (showing previos modeled GIA was about 4x too high — see Climate Audit for details) recalculating GRACE for Antarctica showed fairly food agreement to IceSat.

... Averaged over the global ocean surface, the mean rate of sea level change due to GIA is independently estimated from models at -0.3 mm / yr (Peltier, 2001, 2002, 2009; Peltier & Luthcke, 2009).