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Recommendations from MARCDAT-I, Boulder 2002.
A. SST and Surface Temperature Working Group
Re-examine the historic bias corrections to SST, especially for the
late 1930s through the end of the 1940s.
Status: Good progress
Notes: There are two published correction schemes for
historic bias in SST (Folland C. K. and Parker D. E, 1995: Correction of
Instrumental Biases in Historical Sea Surface Temperature Data,
Quarterly Journal of the Royal Meteorological Society, 121, 319-367 and
Smith, T.M. and R.W. Reynolds, 2002: Bias corrections for historical sea
surface temperatures based on marine air temperatures, J. Climate, 15,
73-87). These corrections need to be reassessed whenever substantial
updates are made to the SST datasets. The Folland and Parker (1995)
correction was developed using the Met Office Marine Databank and
required updating for use with ICOADS. The Hadley Centre have
adapted the corrections to ICOADS (N.A. Rayner, P. Brohan, D.E. Parker, C.K. Folland, J.J. Kennedy, M. Vanicek, T. Ansell and S.F.B. Tett, 2005: Improved analyses of changes and uncertainties in sea surface temperature measured in situ since the mid-nineteenth century, accepted by J. Climate). They also plan to engage in a
more in-depth examination, aimed at determining whether or not
corrections are required post-1941.
All the metadata in the issues of WMO Publication No. 47
(International List of Selected, Supplementary and Auxiliary Ships)
should be digitized.
Status: Some progress
Notes: Imaging of the available published editions and
supplements for 1955-72 has been completed (16 PDF volumes, icoads.noaa.gov/metadata/),
under NOAA's Climate Database Modernization Program, and digitization of
the metadata for that period is underway and planned for completion in
2005. (See also item E, 1.)
Biases in recent night marine air temperature (NMAT) data should be
evaluated, and NMAT interpolation techniques should be re-assessed.
Status: Good progress
Notes: NMAT biases have reassessed (Rayner, N. A., D. E.
Parker, E. B. Horton, C. K. Folland, L. V. Alexander, D. P. Rowell,
E. C. Kent and A. Kaplan, 2003: Global Analyses of SST, Sea Ice and
Night Marine Air Temperature Since the Late 19th Century, Journal of
Geophysical Research 108(D14), 4407, DOI:10.1029/2002JD002670) and
improved interpolation schemes tested (Folland C.K., Salinger M.J.,
Jiang, N. and N. Rayner. Trends and Variations in South Pacific Island
and Ocean Surface Temperature. J. Climate, 16, 2859-2874).
Use geostationary satellite and moored buoy data to analyse the
diurnal cycle of SST, particularly in the tropical west Pacific warm
pool.
Status: Some progress
Notes: Results of analyses of a combination of AVHRR and TMI
data have been published: Gentemann, C., C.J. Donlon, A. Stuart-Menteth,
F.J. Wentz, 2003: Diurnal Signals in Satellite Sea Surface Temperature
Measurements. Geophysical Research Letters , 30(3), 1140-1143 and
Stuart-Menteth A.C., I.S. Robinson, P.G. Challenor 2003: A global study
of diurnal warming using satellite-derived sea surface temperature,
Journal of Geophysical Research 108(C5): art. no. 3155 MAY 22 2003. Use
of GOES geostationary data may be problematic due to calibration
problems.
It is recommended that the Voluntary Observing Ship Climate
(VOSClim) Project be extended, or a parallel project be initiated, to
include buoys.
Status: Withdrawn
Notes: At CLIMAR-II it was decided to withdraw this
recommendation.
Commence regular comparisons of the quality control (QC) procedures
for SST. For these, common in situ input data should be used.
Status: Withdrawn
Notes: One motivation for this was the relative annual cycle seen in SST anomalies of data sets produced by NOAA and those produced by the Hadley Centre. This arose mainly because of the use of daily anomalies in the QC and gridding of the Hadley Centre data sets. The daily climatology was interpolated from the monthly climatology in a non-conservative way, leading to an enhanced annual cycle in the aggregated monthly anomalies (see N.A. Rayner, P. Brohan, D.E. Parker, C.K. Folland, J.J. Kennedy, M. Vanicek, T. Ansell and S.F.B. Tett, 2005: Improved analyses of changes and uncertainties in sea surface temperature measured in situ since the mid-nineteenth century, accepted by J. Climate). This has been improved in the latest Hadley Centre analysis.
Collate NOAA Pathfinder satellite SSTs for inland seas and large
lakes.
Status: Good Progress
Notes: Inland seas and lake temperatures have been
calculated and included in the recent NODC/RSMAS Pathfinder SST Version
5.0 reprocessing (http://www.nodc.noaa.gov/sog/pathfinder4km). However, these data should be treated
skeptically until validation studies have been performed. The
Pathfinder algorithms and quality flagging procedures were not
originally designed for small, inland, freshwater bodies, and no in situ
matchup data from these areas are included in the calculation of the
algorithm coefficients. Work at the University of Edinburgh has shown that open-ocean retrievals of SST from infra-red satellite measurements are not adequate for lake temperature, due to large spatial gradients in the water temperature leading to clearing of false clouds (John Marsham, 2003: Lake temperatures - thermal remote sensing and assimilation into a lake model, PhD Thesis, Institute for Meteorology, University of Edinburgh, 2003).
Develop sub-monthly analyses of SST since 1950.
Status: Good progress
Notes: The Met Office routinely produces pentad (5-day) SST fields and
has a flexible system to grid SST on any spatial and temporal resolution.
Daily analyses on a 1° grid for 1901-2001 are documented in Ishii, M., Shouji, A., Sugimoto, S., and Matsumoto, T., 2005: Objective analyses of sea surface temperature and marine meteorological variables for the 20th century using ICOADS and the Kobe collection, Intl. J. Climatol, 25, 865-879. High resolution daily analyses for 2005 onwards are being produced by the GODAE High Resolution SST Pilot Project.
The Joint Technical Commission for Oceanography and Marine
Meteorology (JCOMM) Expert Team on Sea Ice (ETSI) should provide
recommendations on the blending of sea-ice data and on the
interpretation of microwave observations of sea-ice. This will provide
much-needed information on variations in sea ice thickness.
Status: Good progress
Notes: First version of the blended GDSIDB Arctic sea ice
total concentration data set for 1950-1998 was constructed in December
2002. Dataset is based on four sets of 5-10 days ice charts from the
WMO Global Digital Sea Ice Data Bank. The fifth set is monthly
Northern Polar Region total concentration dataset for1901-1997, also
called John Walsh dataset. All five datasets were reprojected to the
same temporal monthly scale (mid-month) and to the same 15 by 15 minutes
grid. Population of the grid was carried out by means of substitution
values by the most representative which were chosen according to the
zones of responsibility of the national service. Cases of no-information
were populated by monthly robust means. So far, constructed "blended
GDSIDB Arctic sea ice total concentration data set for 1950 -1998" may
be thought as the most informative factual data and is proposed as a
source of WMO norms on sea ice for 1950-1998 period. Further progress is
anticipated in changing general climatic values to typical ones and
involving some regional data sets presently absent in blended data set.
NCDC also produce SST analyses incorporating sea-ice
information.
It is desirable that the ETSI should provide an inventory of
historical sea ice data for the Southern Ocean.
Status: In progress
Notes: ETSI-I agreed "to develop blended sea ice variables
for global climate analysis and to prepare historical sea ice data
information for the Southern Ocean" during the inter-sessional period.
Status report will be available by ETSI-II (Autumn 2004).
The use of satellite SSTs in relationships between SST and sea ice
concentration should be re-assessed owing to possible contamination of
these SSTs by the sea-ice. Improved sea-ice data and relationships
should be incorporated into SST analyses.
Status: Good progress
Notes: Project funded by Hadley Centre and carried out at
University of Edinburgh has used ATSR-2 brightness temperatures to
develop an improved retrieval in polar regions. A demonstration data
set of SST values on a daily 1 km grid for two days per month throughout
1999 has been produced. This will be taken forward when resources are
available.
Cloud-clearing techniques for satellite-based infrared SSTs should
be compared.
Status: Some progress
Notes: A NOAA-funded project has developed a new Bayesian
cloud detection algorithm for GOES. The GOES Bayesian cloud mask is
running in parallel with the operational threshold-based scheme.
Individual uncertainty estimates can be assigned to every single SST
retrieval.
Regular comparisons of SST analyses should commence.
Status: Little progress
Notes: Some informal comparisons made at the Hadley
Centre
All SST analyses need to include gridded fields of analysis error
including bias correction error. Error covariances are also needed.
Status: Good progress
Notes: Several analyses including ERSST.v2 (Smith, T.M., and
R.W. Reynolds, 2004: Improved Extended Reconstruction of SST
(1854-1997), Journal of Climate, 17, 2466-2477) and HadSST2 (N.A. Rayner, P. Brohan, D.E. Parker, C.K. Folland, J.J. Kennedy, M. Vanicek, T. Ansell and S.F.B. Tett, 2005: Improved analyses of changes and uncertainties in sea surface temperature measured in situ since the mid-nineteenth century, accepted by J. Climate) now have accompanying
error estimates and covariances.
Create monthly and sub-monthly blended SST/sea-ice products.
Estimates of errors, and indications of sources of data, should be
included in the product.
Status: Good progress
Notes: ERSST.v2
(
http://www.ncdc.noaa.gov/oa/climate/research/sst/sst.html)
incorporates sea ice
concentration to improve high-latitude SST and includes error estimates.
The Hadley Centre plans to develop HadISST2, which will contain error
estimates.
For further information, or to provide status updates, contact:
