How well do stratospheric reanalyses reproduce high-resolution satellite temperature measurements?
How well do stratospheric reanalyses reproduce high-resolution satellite temperature measurements?
复制标题
平流层再分析再现高分辨率卫星温度测量结果的效果如何?
DOI:
10.5194/acp-18-13703-2018
复制
发表时间:
2018
影响因子:
6.3
通讯作者:
N. Hindley
中科院分区:
文献类型:
--
作者:
C. Wright;N. Hindley
Abstract. Atmospheric reanalyses are data-assimilating weather models
which are widely used as proxies for the true state of the atmosphere in the
recent past. This is particularly the case for the stratosphere, where
historical observations are sparse. But how realistic are these stratospheric
reanalyses? Here, we resample stratospheric temperature data from six modern
reanalyses (CFSR, ERA-5, ERA-Interim, JRA-55, JRA-55C and MERRA-2) to produce
synthetic satellite observations, which we directly compare to retrieved
satellite temperatures from COSMIC, HIRDLS and SABER and to brightness
temperatures from AIRS for the 10-year period of 2003–2012. We explicitly
sample standard public-release products in order to best assess their
suitability for typical usage. We find that all-time all-latitude
correlations between limb sounder observations and synthetic observations
from full-input reanalyses are 0.97–0.99 at 30 km in altitude, falling to
0.84–0.94 at 50 km. The highest correlations are seen at high latitudes and
the lowest in the sub-tropics, but root-mean-square (RMS) differences are
highest (10 K or greater) in high-latitude winter. At all latitudes,
differences increase with increasing height. High-altitude differences become
especially large during disrupted periods such as the post-sudden
stratospheric warming recovery phase, in which zonal-mean differences can be as
high as 18 K among different datasets. We further show that, for the
current generation of reanalysis products, a full-3-D sampling approach (i.e.
one which takes full account of the instrument measuring volume) is always
required to produce realistic synthetic AIRS observations, but is almost
never required to produce realistic synthetic HIRDLS observations. For
synthetic SABER and COSMIC observations full-3-D sampling is required in
equatorial regions and regions of high gravity-wave activity but not
otherwise. Finally, we use cluster analyses to show that full-input
reanalyses (those which assimilate the full suite of observations, i.e.
excluding JRA-55C) are more tightly correlated with each other than with
observations, even observations which they assimilate. This may suggest that
these reanalyses are over-tuned to match their comparators. If so, this could
have significant implications for future reanalysis development.
影响因子:
6.3
作者:
Fujiwara, Masatomo;Wright, Jonathon S.;Zou, Cheng-Zhi
通讯作者:
Zou, Cheng-Zhi
影响因子:
6.3
作者:
Hindley, N. P.;Wright, C. J.;Mitchell, N. J.
通讯作者:
Mitchell, N. J.