Marine Climatology from Research Vessels

1
Marine Climatology from Research Vessels

• Shawn R. Smith1, Scott D. Woodruff2, and Steve
  Worley3

1Center for Ocean-Atmospheric Prediction Studies,
FSU, Tallahassee, FL USA 2NOAA/OAR/Earth System
Research Laboratory, Boulder, CO, USA 3National
Center for Atmospheric Research, Boulder, CO, USA
MARCDAT-II, Exeter, UK
Funding provided by NOAA Office of Climate
Observation and the NOAA Environmental Services
Data and Information Management program.
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Overview

• For decades, research vessels (RVs) have been
  collecting a wide array of atmospheric and ocean
  measurements over the global oceans.
• E.g., Russian RV data (1936-2000) provided as
  auxiliary data in ICOADS
• Recent technological advances have allowed for
  transmission of high volumes of marine climate
  observations from RVs.
• Presently, RV marine reports make up only a small
  fraction of records in ICOADS
• Bridge reports not transmitted routinely
• Stewardship of science data is fragmented
• Typically held by chief scientists, operating
  institutions, or national archives
• No clear path exist to provide data to ICOADS

Courtesy NOAA OCO
3
Sources of data from RVs

• All vessels equipped with meteorological sensors
  to aid navigation
• These sensors typically used for reports by
  bridge crew
• Scientific instrument systems (e.g., IMET, NOAA
  SCS, Multimet)

• Typically the bridge and scientific instrument
  systems are independent.
• Insufficient metadata to determine whether marine
  reports in ICOADS are from bridge or science
  observing systems

Courtesy NOAA OCO
4
Advantages of RV climate data

• Operate in all parts of the ocean, including
  regions of extreme conditions (e.g., polar
  latitudes, high wind regimes).
• Science systems provide
• High sampling rates
• Research data quality (on par with delayed
  mooring data)
• Instruments monitored by onboard technicians
• Additional measurements not provided in bridge
  reports (radiation, direct fluxes, etc.)
• RVs provide ideal platform to develop new sensors
  (CO2, infrared SST)

Courtesy NOAA OCO
5
RV data reaching ICOADS

• Extracting RV reports from ICOADS for 1997
  reveals
• Wide coverage of ocean
• Low observational density

• 80000 individual marine reports from 154 vessels
• Highest densities around Japan and Europe
• 60 of reports provided by only 12 vessels
• 49 of reports from 21 vessels participating in
  WOCE
• Polarstern alone provides 10 of obs.

Courtesy NOAA OCO
6
Problem of locating RVs

• Creating plots of research vessel coverage
  problematic
• Most common method is to search for vessel call
  sign
• Locating call signs difficult, typically from Pub
  47 or vessel operators
• Change frequently
• Recent addition of kind of vessel metadata to
  ICOADS helps
• Only as complete as Pub 47 it is based upon
• Result omits many well known vessels (e.g.,
  Meteor)
• Research vessel tracking system needed
• Surprisingly hard just to find out when and where
  RVs are making measurements
• Web resources (e.g., www.researchvessels.org) are
  incomplete and under-funded
• J. Gould and others have proposed that JCOMM-OPS
  take on responsibility

Courtesy NOAA OCO
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Providing FSU data to ICOADS

• FSU RV data center is working to make historical
  and near-real time RV data available to ICOADS.
• Historical data
• Current FSU holdings contain science data from
  WOCE and other select cruises (1988-Present)
• Additional science and bridge data from operating
  institutions and national archives could be
  acquired with additional funding
• Near-real time data
• obtained through the Shipboard Automated
  Meteorological and Oceanographic System (SAMOS)
  initiative
• Science data provided to FSU on daily basis
• Pilot project underway with Knorr and Atlantis
• Additional information in poster presentation

• All FSU data have undergone scientific data
  quality evaluation

Courtesy NOAA OCO
8
Providing FSU data to ICOADS

• Most FSU marine reports must be temporally
  sub-sampled for ICOADS
• Similar methods are currently employed by ICOADS
  for moored buoys

• Bulk of RV records are at one- minute intervals
• Desire to retain diurnal cycle
• FSU producing 10-min. averages leading up to top
  of hour
• Developing hourly sub-samples in IMMA format for
  ICOADS
• Include average and measure of uncertainty for
  each value
• Additional parameters beyond core ICOADS records
• Format may be useful for archiving future RV and
  mooring reports

Courtesy NOAA OCO
9
Comparing FSU to ICOADS

• Number of marine reports for 22 WOCE cruises of
  the RV Meteor (1990 - 1997)

• Reports counted over length of cruise known to
  FSU
• 12229 science data reports from FSU
• 6958 reports available in ICOADS

Courtesy NOAA OCO
10
Comparing FSU to ICOADS

• Number of marine reports for 26 WOCE cruises of
  the RV Knorr (1990 - 1997)

• 18071 science data reports from FSU
• 324 reports available in ICOADS
• A substantial increase in records can be achieved
  by adding science observations to ICOADS

Courtesy NOAA OCO
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Comparing FSU to ICOADS

• For the WOCE cruises of the Meteor and the Knorr,
  how well do reports found in ICOADS compare to
  sub-sampled data from FSU archive?
• Note comparisons do not take into account
  differing sensor depths (some metadata lacking)
• ICOADS for Knorr are colder than FSU reports.

Courtesy NOAA OCO
12
Comparing FSU to ICOADS

• Air temperatures show similar cold bias in ICOADS
  reports for the Knorr (or warm bias for the FSU
  data).
• Lower number of matches may skew results for
  Knorr
• Meteor comparison very good without adjusting for
  differing thermometer heights (ICOADS 11 m, FSU
  28 m)

Courtesy NOAA OCO
13
Comparing FSU to ICOADS

• Biases are low for wind speed on both vessels.
• Meteor shows more scatter at higher wind speeds
  (both measurements taken at 40 m height)
• Anemometer height for Knorr not available for
  ICOADS reports

Courtesy NOAA OCO
14
Questions to consider

• Should data averaged from high-sampling rate
  science systems (SAMOS, moorings) be retained as
  independent in ICOADS (not replace existing
  GTS/DM reports)?
• Can an effort be launched to request
  participation by RVs in routine VOS reporting?
• Many operators seem unaware of VOS reporting
• Can RV operators provide metadata regarding
• Whether and how they provide routine marine
  weather reports?
• Whether these reports are derived from science
  instrument system?
• Note some effort to improve metadata can be
  taken up by the SAMOS initiative
• What is the volume of RV science and bridge
  observations held by operating institutions and
  national archives?

Courtesy NOAA OCO
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Final Thoughts

• Research vessels are presently an underutilized
  resource for marine climate observations
• Efforts should be made to mine historical RV
  observations from operating institution and
  national archives
• This effort could support ongoing plans for
  atmospheric and oceanic reanalyses
• An expansion of near-real time transmission of
  science data from RVs should be encouraged
• Resources and the need to improve ship-to-shore
  communications are primary limitations
• SAMOS initiative seeks to recruit additional
  vessels in 2006
• 1st Joint GOSUD/SAMOS Workshop scheduled for May
  2006 (interested parties should contact
  smith_at_coaps.fsu.edu)

Courtesy NOAA OCO