Post on 27-Mar-2015
transcript
Use of VOS data in Climate Products
Elizabeth Kent and Scott Woodruff
National Oceanography Centre, Southampton
NOAA Earth System Research Laboratory
Use of VOS data beyond Numerical Weather Prediction
IPCC - global ocean temperature trends
Satellite bias removal
Satellite cal/val
WCRP SURFA flux validation
Flux datasets
Merging with metadata and ODAS into ICOADS for
reanalysis and other climate applications
Evolving ICOADS coverage by platform type: Jul 1980 / 2005Evolving ICOADS coverage by platform type: Jul 1980 / 2005(oceanographic data not yet blended after 1997)(oceanographic data not yet blended after 1997)
ship
oceanog.
drifting
moored
C-MAN
Recent developments (1)
Statement from JCOMM-II on importance of data
overseen by SOT being collected according to the
GCOS Climate Monitoring Principles
Ship security and callsign masking
• Both these issues to be discussed elsewhere at SOT -
remembering that the requirements are also critical for
climate applications
Recent developments (2)
General reduction over recent years of quantity of
data from VOS
Coupled with some increases in AWS data
• > frequency & < independence
Need for user requirements and adequacy monitoring
• Are the user requirement definitions adequate?
• Adequacy monitoring required for VOS (ETMC)
Recent VOS data (GTS-only 1998-) + WMO Pub. 47Recent VOS data (GTS-only 1998-) + WMO Pub. 47
Green: reports with metadata
Declining VOS…
2005-6 not plotted yet
Adequacy requirements
User requirements for VOS not always well defined
VOS observations harder to assess for adequacy than
other types of observations (e.g. drifters, ARGO)
VOS are an important source of several GCOS Essential
Climate Variables (e.g. SST, air temperature, humidity)
Lack of targets and assessments leads to lack of
investment and planning
Met Office-funded ASMOS project
ASMOS: Assessment of the Marine Observing System
Assessments of uncertainty
in monthly fields
Relation of uncertainty to
simple metrics
• Number of days sampled
• Number of platforms
• Reports with metadata
• Sampling of diurnal cycle
A start - but more work
needed
Recent developments (3)
The climate data stream: issues include
• Increased reliance on GTS reports, is this OK?
• Difference in data streams from different centres,
missing obs., data being changed and not flagged
• Move to TDCFs: implications for consistency with
historical data and data quality
• Need to quantify added value of delayed mode
Recommendations for SOT to Consider
SOT should consider adding its support to the request by JCOMM for a scientific
review of user requirements for the VOSClim and VOS programs, spanning both
real time and climate applications.
SOT should aim to deliver the requirement for ship identification information to
be available for all observations in the climate archive to ensure that
observational metadata available in delayed mode (such as WMO Publication
No. 47) can be associated with individual ship reports.
SOT should call for additional support to be made available for the provision of
VOS metadata, both in near real time and delayed mode.
SOT should call for a review of the provision of VOS reports both in real time
and delayed mode and contribute to the Expert Team on Marine Climatology
(ETMC) Task Team on Delayed Mode VOS (TT-DMVOS).