Met Office Historical Marine Air Temperature (MOHMAT/HadMAT) dataset
MOHMAT, (Met Office Historical Marine Air Temperature) is a gridded
dataset of marine air temperature anomalies covering the period
1856-present. The current version of the dataset is MOHMAT4, which is
described in paper below.
MOHMAT4 has been updated to produce MOHMAT43N and HadMAT1 both of which are described in the references.
Brief description of the data
MOHMAT is produced by taking in-situ measurements of MAT from ships and
buoys, rejecting measurements which fail quality checks,
converting the measurements to anomalies by subtracting climatological
values from the measurements, and averaging the resulting anomalies on
a 5 by 5 degree monthly grid. Note that only night-time data are used,
because day-time data are corrupted by heat island effects. See the
references for details.
Up to 1996 the measurements used are those in the U.K. Marine
Data Bank; more recent years use data coming in through the GTS. MOHMAT
is no longer updated.
After gridding the anomalies, bias corrections are applied to
remove spurious trends caused by changes in ship deck heights and
various unusual operational practices, and the data are smoothed to
reduce noise.
An optimal
interpolated version of this dataset, HadMAT1, is
also available. It has been shown to
be better than the non optimally interpolated NMAT data when it exists for very many applications (see references for details).
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References
When using the data set in a paper, the following is the correct citation to use:
Global analyses of sea surface temperature, sea ice, and night marine air temperature
since the late nineteenth century by N.A. Rayner, D.E. Parker, Horton, E.B., C.K. Folland, L.V. Alexander, D.P. Rowell, E.C. Kent, A. Kaplan,
J. Geophys. Res., 108, No. D14, 4407, 2003. (pdf ~17 Mb)
The following references should also be read:
Marine Surface Temperature: Observed variations
and data requirements by D.E. Parker, C.K. Folland and M.
Jackson, Climatic Change 31: 559-600, 1995.
Trends and Variations in South Pacific Island and Ocean Surface Temperature by Folland C.K., Salinger M.J., Jiang, N.
and N. Rayner, 2003 J. Climate, 16(17), 2859-2874.
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Other information
MOHMAT43N represents and improvement to the ship deck height
corrections used in MOHMAT42N and is available here.
Dataset produced in collaboration with:
