HadTH - An Analysis of Tropospheric Humidity Trends from Radiosondes
HadTH is an analysis of tropospheric
humidity from radiosondes [the Hadley Centre gridded
homogenized radiosonde humidity dataset (HadTH)],
to estimate trends and uncertainty in both relative and
specific humidity across the Northern Hemisphere over
the last 30 years. These data provide vertical resolution not
available in many long-term surface or satellite-based
measurements, and build upon earlier analyses of the
radiosonde data, therefore complementing and building
the existing evidence base. The purpose of HadTH is
specifically to determine whether the radiosondes provide
sufficient evidence to confidently reject the null
hypothesis that relative humidity in the troposphere has
remained at a constant level through recent climate
change. Therefore, due care should be taken if HadTH
is used for other applications because the historical
biases affecting the radiosonde humidity data have not
yet been as rigorously assessed as those for temperature.
Brief description of the data
This website contains data from a number of stages of the dataset development, so that the biases, their origin, and the associated adjustments are made clear. The
methodology follows closely that described in QUARC and the documents linked below.
The figure above has been taken from McCarthy et al. (2009). See the paper for
more information. It shows estimates of northern extra-tropical trends between 1973
and 2003. Dashed lines are the unadjusted data, solid lines and error bars are from HadTH.
Data are available from the download page without charge for the purposes of private study and scientific
research, but please read the terms and conditions. You do not
have to register, but it will help us if you do.
||For problems getting or understanding the data, or to suggest some improvement please leave feedback. If you find the data useful, please return and tell us what you did with it.
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The estimates of trend uncertainties are described in this paper:
McCarthy, M.P., P.W. Thorne, and H.A. Titchner, 2009: An Analysis of Tropospheric Humidity Trends
J. Climate ,
22, :5820-5838 doi:10.1175/2009JCLI2879.1
The homogenisation system methodology is described in the following paper:
McCarthy, M. P., H. A. Titchner, P. W. Thorne, S. F. B. Tett, L.Haimberger, D. E. Parker, 2008:
Assessing bias and uncertainty in the HadAT adjusted radiosonde
climate record, J. Climate., 21, doi: 10.1175/2007JCLI1733.1 (PDF file)