ICOADS Web information page (Tuesday, 11-Feb-2014 19:22:58 UTC):

Release 1b (1950-79) Overview

The following text, adapted from Woodruff et al. (1998), describes some
of the data corrections and enhancements made for Release 1b:

A variety of data additions was made to Release 1b.  For example, Russia
has provided its Marine Meteorological Data Set of ship data from the
former Soviet Union extending back to 1888 (1980-94 data were used for
Release 1a), plus Arctic data back to 1950 from manned "North Pole" (NP)
stations on ice floes.  Surface-level sea temperatures extracted from
oceanographic profiles were added from the 1994 World Ocean Atlas (WOA)
(Levitus and Boyer, 1994; Boyer and Levitus, 1994).  Another important
new input for Release 1b was drifting buoy data gathered by MEDS for the
FGGE period (1978-79).

Two errors corrected or mitigated as part of Release 1b processing
involved widespread temperature biases in Global Telecommunications
System (GTS) data: The first occurred in data from U.S. Air Force Global
Weather Central (GWC; deck 888), which represents the principal GTS
source for COADS during 1973-79.  GWC temperatures (air, sea surface,
and dew point) were 0.2C lower than they should be for the period 1973
through approximately April 1977, stemming from confusion over a change
in the Kelvin base value in the original Air Force format.  The second
problem involved a truncation correction applied many years ago to
Monterey Telecommunications (1966-73) air temperatures, which produced
an average Monterey bias of approximately +0.4C because many early
temperatures were reported in whole degrees.  Reversal of the correction
yielded better agreement with other sources during 1966-69, whereas
during 1970-73 retention of the original correction by NCDC (i.e., no
adjustment by COADS) was deemed more appropriate.

Woodruff, S.D., H.F. Diaz, J.D. Elms, and S.J. Worley, 1998: COADS
Release 2 Data and Metadata Enhancements for Improvements of Marine
Surface Flux Fields. Phys. Chem. Earth, 23, 517-527.

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Updated: Feb 11, 2014 19:22:58 UTC