GCOS GOOS WCRP/OOPC IX/3
However, none of these advances is complete! For example:
Millions of marine observations remain to be located and digitized from logbooks
(e.g., Fig. 1), and millions that are already digitized remain to be blended into
The biases in marine temperatures around 1939 45 are still poorly understood.
Daytime MAT data need to be made useable. Our knowledge of biases for as much
of the past as possible needs to be complemented by inclusion of appropriate
metadata in data sets, so that proxy and historical data can be made compatible
with modern data; also enabling future data to be made compatible with current
data. This is an application of the GCOS Climate Monitoring Principles (Appendix
2 of GCOS, 2003). However, it is recognised that finding some of the required
metadata will be difficult and may need augmenting by special studies of the
character of the data to make deductions about some of the observational practices.
We are still improving our assessments of uncertainties and need to compare
techniques for making these assessments; we also need to specify our target
The global observing system still leaves large areas unobserved at the ocean
surface and especially below.
Other Boulder recommendations, such as creation of sub monthly analyses of SST and
sea ice, and adjustment of historical wind speed data, are still at an early stage. CLIMAR II
supported the need for sub monthly (pentad) analyses because they provide useful ground
truth even though they may be noisy or even impossible over most of the globe and most of
the instrumental record because of the sparsity of observations. Pentad SST analyses based on
satellite data (e.g. Reynolds et al., 2002) are very valuable but require in situ data for
validation and often for calibration also. Adjustment of historical wind speeds is particularly
difficult without metadata. Some useful work has been done for the post Second World War
period (e.g. Ward and Hoskins, 1996), which showed that the problems in the raw data are
indeed serious, but this needs extending throughout the ICOADS period. QC techniques for
all parameters need to be fully and consistently documented; if possible, QC methods used
throughout ICOADS should be homogeneous.
There were seen to be shortcomings in the access to ICOADS data. Do we have
optimal methods for collecting, preparing and providing information? There are many,
overlapping sources of data and products, and the problem of optimising data provision is
complex. Many users are working with outdated versions of COADS. Often data are
available, but it is difficult for the uninitiated to discover what is there. There should be a
web based route map to the best available data which should be widely advertised to all the
various user communities.
The Boulder workshop recommended that the Voluntary Observing Ships Climate
(VOSClim) Project be extended, or a parallel project be initiated, to include buoys. CLIMAR
II discarded this recommendation. With the planned availability of buoy metadata, buoy
versus model comparison will be possible from existing datasets. Operationally the
monitoring of buoy data already takes place.