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Evaluation of CMIP5 upper troposphere and lower stratosphere geopotential height with GPS radio occultation observations
Author(s) -
Ao Chi O.,
Jiang Jonathan H.,
Mannucci Anthony J.,
Su Hui,
Verkhoglyadova Olga,
Zhai Chengxing,
Cole Jason,
Donner Leo,
Iversen Trond,
Morcrette Cyril,
Rotstayn Leon,
Watanabe Masahiro,
Yukimoto Seiji
Publication year - 2015
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
eISSN - 2169-8996
pISSN - 2169-897X
DOI - 10.1002/2014jd022239
Subject(s) - geopotential height , radio occultation , environmental science , troposphere , climatology , middle latitudes , stratosphere , geopotential , latitude , atmospheric sciences , coupled model intercomparison project , occultation , climate model , meteorology , climate change , geology , geography , ionosphere , precipitation , geodesy , oceanography , physics , astronomy , geophysics
We present a detailed comparison of geopotential height fields between the Coupled Model Inter‐Comparison Project phase 5 (CMIP5) models and satellite observations from GPS radio occultation (RO). Our comparison focuses on the annual mean, seasonal cycle, and interannual variability of 200 hPa geopotential height in the years 2002–2008. Using a wide sample of atmosphere‐only model runs (AMIP) from the CMIP5 archive, we find that most models agree well with the observations and weather reanalyses in the tropics in both the annual means and interannual variabilities. However, the agreement is poor over the extratropics with the largest model spreads in the high latitudes and the largest bias in the southern middle to high latitudes that persist all seasons. The models also show excessive seasonal variability over the Northern midlatitude land areas as well as the Southern Ocean but insufficient variability over the tropics and Antarctica. While the underlying causes for the model discrepancies require further analyses, this study demonstrates that global observations from GPS RO provide accurate benchmark‐quality measurements in the upper troposphere and lower stratosphere through which biases in climate models as well as weather reanalyses can be identified.