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 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).