Decadal Prediction Skill in the GEOS-5 Forecast System
A suite of decadal predictions has been conducted with the NASA Global Modeling and Assimilation Office's (GMAO's) GEOS-5 Atmosphere-Ocean general circulation model. The hind casts are initialized every December 1st from 1959 to 2010, following the CMIP5 experimental protocol for decadal p...
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ftnasantrs:oai:casi.ntrs.nasa.gov:20150008258 2023-05-15T17:31:57+02:00 Decadal Prediction Skill in the GEOS-5 Forecast System Rienecker, Michele M. Zhao, Bin Ham, Yoo-Geun Suarez, Max J. Vikhliaev, Yury Marshak, Jelena Schubert, Siegfried D. Vernieres, Guillaume Unclassified, Unlimited, Publicly available December 14, 2013 application/pdf http://hdl.handle.net/2060/20150008258 unknown Document ID: 20150008258 http://hdl.handle.net/2060/20150008258 Copyright, Distribution as joint owner in the copyright CASI Oceanography Earth Resources and Remote Sensing Meteorology and Climatology GSFC-E-DAA-TN21507 Climate Dynamics 42; 2-Jan; 1-20 2013 ftnasantrs 2019-07-21T00:11:07Z A suite of decadal predictions has been conducted with the NASA Global Modeling and Assimilation Office's (GMAO's) GEOS-5 Atmosphere-Ocean general circulation model. The hind casts are initialized every December 1st from 1959 to 2010, following the CMIP5 experimental protocol for decadal predictions. The initial conditions are from a multivariate ensemble optimal interpolation ocean and sea-ice reanalysis, and from GMAO's atmospheric reanalysis, the modern-era retrospective analysis for research and applications. The mean forecast skill of a three-member-ensemble is compared to that of an experiment without initialization but also forced with observed greenhouse gases. The results show that initialization increases the forecast skill of North Atlantic sea surface temperature compared to the uninitialized runs, with the increase in skill maintained for almost a decade over the subtropical and mid-latitude Atlantic. On the other hand, the initialization reduces the skill in predicting the warming trend over some regions outside the Atlantic. The annual-mean Atlantic meridional overturning circulation index, which is defined here as the maximum of the zonally-integrated overturning stream function at mid-latitude, is predictable up to a 4-year lead time, consistent with the predictable signal in upper ocean heat content over the North Atlantic. While the 6- to 9-year forecast skill measured by mean squared skill score shows 50 percent improvement in the upper ocean heat content over the subtropical and mid-latitude Atlantic, prediction skill is relatively low in the sub-polar gyre. This low skill is due in part to features in the spatial pattern of the dominant simulated decadal mode in upper ocean heat content over this region that differ from observations. An analysis of the large-scale temperature budget shows that this is the result of a model bias, implying that realistic simulation of the climatological fields is crucial for skillful decadal forecasts. Other/Unknown Material North Atlantic Sea ice NASA Technical Reports Server (NTRS) |
institution |
Open Polar |
collection |
NASA Technical Reports Server (NTRS) |
op_collection_id |
ftnasantrs |
language |
unknown |
topic |
Oceanography Earth Resources and Remote Sensing Meteorology and Climatology |
spellingShingle |
Oceanography Earth Resources and Remote Sensing Meteorology and Climatology Rienecker, Michele M. Zhao, Bin Ham, Yoo-Geun Suarez, Max J. Vikhliaev, Yury Marshak, Jelena Schubert, Siegfried D. Vernieres, Guillaume Decadal Prediction Skill in the GEOS-5 Forecast System |
topic_facet |
Oceanography Earth Resources and Remote Sensing Meteorology and Climatology |
description |
A suite of decadal predictions has been conducted with the NASA Global Modeling and Assimilation Office's (GMAO's) GEOS-5 Atmosphere-Ocean general circulation model. The hind casts are initialized every December 1st from 1959 to 2010, following the CMIP5 experimental protocol for decadal predictions. The initial conditions are from a multivariate ensemble optimal interpolation ocean and sea-ice reanalysis, and from GMAO's atmospheric reanalysis, the modern-era retrospective analysis for research and applications. The mean forecast skill of a three-member-ensemble is compared to that of an experiment without initialization but also forced with observed greenhouse gases. The results show that initialization increases the forecast skill of North Atlantic sea surface temperature compared to the uninitialized runs, with the increase in skill maintained for almost a decade over the subtropical and mid-latitude Atlantic. On the other hand, the initialization reduces the skill in predicting the warming trend over some regions outside the Atlantic. The annual-mean Atlantic meridional overturning circulation index, which is defined here as the maximum of the zonally-integrated overturning stream function at mid-latitude, is predictable up to a 4-year lead time, consistent with the predictable signal in upper ocean heat content over the North Atlantic. While the 6- to 9-year forecast skill measured by mean squared skill score shows 50 percent improvement in the upper ocean heat content over the subtropical and mid-latitude Atlantic, prediction skill is relatively low in the sub-polar gyre. This low skill is due in part to features in the spatial pattern of the dominant simulated decadal mode in upper ocean heat content over this region that differ from observations. An analysis of the large-scale temperature budget shows that this is the result of a model bias, implying that realistic simulation of the climatological fields is crucial for skillful decadal forecasts. |
format |
Other/Unknown Material |
author |
Rienecker, Michele M. Zhao, Bin Ham, Yoo-Geun Suarez, Max J. Vikhliaev, Yury Marshak, Jelena Schubert, Siegfried D. Vernieres, Guillaume |
author_facet |
Rienecker, Michele M. Zhao, Bin Ham, Yoo-Geun Suarez, Max J. Vikhliaev, Yury Marshak, Jelena Schubert, Siegfried D. Vernieres, Guillaume |
author_sort |
Rienecker, Michele M. |
title |
Decadal Prediction Skill in the GEOS-5 Forecast System |
title_short |
Decadal Prediction Skill in the GEOS-5 Forecast System |
title_full |
Decadal Prediction Skill in the GEOS-5 Forecast System |
title_fullStr |
Decadal Prediction Skill in the GEOS-5 Forecast System |
title_full_unstemmed |
Decadal Prediction Skill in the GEOS-5 Forecast System |
title_sort |
decadal prediction skill in the geos-5 forecast system |
publishDate |
2013 |
url |
http://hdl.handle.net/2060/20150008258 |
op_coverage |
Unclassified, Unlimited, Publicly available |
genre |
North Atlantic Sea ice |
genre_facet |
North Atlantic Sea ice |
op_source |
CASI |
op_relation |
Document ID: 20150008258 http://hdl.handle.net/2060/20150008258 |
op_rights |
Copyright, Distribution as joint owner in the copyright |
_version_ |
1766129846950297600 |