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ETMC interactions with ETWCH, including wave and storm surge data

ETMC interactions with ETWCH, including wave and storm surge data. Val Swail and Scott Woodruff. INTERACTIONS WITH ETWCH. Global extreme wave event archive (EWDS) Development of monthly wave climate summaries Global storm surge climatology Marine climate indices for waves and storm surge

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ETMC interactions with ETWCH, including wave and storm surge data

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  1. ETMC interactions with ETWCH, including wave and storm surge data Val Swail and Scott Woodruff

  2. INTERACTIONS WITH ETWCH • Global extreme wave event archive (EWDS) • Development of monthly wave climate summaries • Global storm surge climatology • Marine climate indices for waves and storm surge • (dealt with under agenda item 3.3)

  3. Global storm surge climatology • ETWCH is presently developing an approach to a global storm surge climatology. This project has two components: • developing a consistent approach to the statistical analysis of tide gauge records where one is lucky enough to have them: • web repository of all UK tide gauge analyses established http://www.ntslf.org/storm-surges/storm-surge-climatology • Dutch data is now being similarly analyzed • US and Canadian tide gauge data to follow • through ETWCH, the rest of the world will be encouraged to do likewise, following the guidance developed by ETWCH.

  4. Global storm surge climatology • global model hindcasts that are credible: • develop comprehensive statistical model of storm surge distributions, explaining why the main body of observed storm surges follow a gamma distribution; • prove joint probability methods are the most appropriate for estimating extreme sea level probabilities in regions of high tidal range • examine whether plausible limits on storm surge maxima constrain the family of extreme value methods for the most extreme storm surges; • critically assess whether extreme water level results from a multi-decadal hydrodynamic model hindcast represent a reliable means of deriving extreme water level statistics; • create a zoomable world map of storm surge climatology.

  5. Monthly wave climate summaries The notion of producing monthly wave climate summaries in ICOADS has been considered for several years. MARCDAT-3 (Frascati, Italy, 2-6 May 2011) panel discussion noted that monthly wave summaries were expected to be useful to a wide range of users although the existence of alternative satellite or hindcasting wave products was noted. MARCDAT-3 concluded that wave and swell summaries would be worth producing, if ICOADS project resources could be located to add them to the regular product mixture. There has been no progress to date on developing wave climate summaries in ICOADS, largely due to broader issues related to sustaining ICOADS as a whole, and the general lack of resources for new developments. Future: short (1-2 years) or medium term (post-JCOMM-5), or drop altogether?

  6. JCOMM EXTREME WAVE DATA SET Motivation: JCOMM Expert Team on Waves and Coastal Hazard Forecasting Systems noted the need for high quality measured wave data sets (both in situ and satellite) in areas of open ocean away from continental margins for use in model validation, forecast verification, satellite calibration and validation as well as climatology Proposal: JCOMM supported the development of a JCOMM-label data base of wave measurements in “very extreme storm seas”, SWH ≥ 14 m Catalyst: Rockall Trough storm of February 8, 2000 measured 18.5 m SWH, then the largest known reliably measured wave height, off Scotland; and other recent large events Requirement:Ongoing contributions of high quality wave measurements of extreme storm seas with appropriate documentation and metadata to the EWDS Plan: Establish a Pilot Project to scan in situ data bases in US, UK, Canada; include a satellite component initially based on Oceanweather scans from GlobWave Holliday, N. P., M. J. Yelland, R. Pascal, V. R. Swail, P. K. Taylor, C. R. Griffiths, and E. Kent, 2006: Were extreme waves in the Rockall Trough the largest ever recorded?, Geophys. Res. Lett., 33, L05613, doi:10.1029/2005GL025238.

  7. In situ component

  8. In-situ Measurements of VESS

  9. Some wave measurement systems

  10. Measured Wave Data on the GTS

  11. Oceanweather in situ Scans ICOADS • Data from http://rda.ucar.edu/datasets/ds540.0/ • 1662-2007 ICOADS Release 2.5 IMMA Format • 2008-Present ICOADS Release 2.5P (Real-Time GTS) IMMA Format ISDM/MEDS • Data from ftp://ftp.meds-sdmm.dfo-mpo.gc.ca/ALPHAPRO/WAVE/waveshare/FBYEARS • 1970-2011 NODC • Data from ftp://ftp.nodc.noaa.gov/pub/f291/ • 197001-201103 F291 ASCII Format • 201104-Present netCDF

  12. In Situ Scans of Extreme Waves

  13. Extreme waves around the UK Dataset taken from 78 moored buoys, rigs & platforms in and around the UK, from a dataset of over 5 million obs 96 “genuine” extreme waves identified from 12 sites

  14. VESS events above 12 meters by source • ICOADS 742,288* • ISDM/MEDS 415 • NODC 385 • MetOffice 96 (> 14m)

  15. Sample CSV EWDS File

  16. Satellite altimeter component

  17. GlobWave Altimeter Database • GlobWave provides a new, homogenized, quality controlled, single point of access database containing virtually the entire record of satellite altimeter HS and WS measurements acquired since 1991. • The database is described in a general way in the Wave Data Handbook for GlobWave (Ash et al, 2011) with an in-depth description of the quality control and calibration of each of the missions by Queffeulou and Croize-Fillon (2010) • EWDS peak extraction described in: Cardone, V.J., B.T. Callahan, H. Chen, A.T. Cox, M.A. Morrone and V.R. Swail, 2014. Global Distribution and Risk to Shipping of Very Extreme Sea States (VESS), International Journal of Climatology, doi: 10.1002/joc.3936 Altimeter missions contained in GlobWave (above) and number of missions by year (below)

  18. VESS Detection by Significant Wave Height Distribution of orbit segment peaks (counts and relative percentage occurrence) sorted by basin for indicated HS thresholds

  19. Sustainability – Update In situ • Add additional countries to the initial Pilot Project • Ongoing commitment from national wave archives to scan and provide extreme data sets to EWDS, e.g. annually • Update metadata • Commitment to hosting the data base (also satellite) Satellite Altimeter • GlobWave project has ended • Not clear if satellite altimeter data sets are still being archived in a collective data base, with homogenization, so risk returning to the bad old days pre-GlobWave • Not obvious who would carry out extreme scans for EWDS

  20. Metadata • Metadata issues: generally the situation is abysmal regarding historical buoy/platform instrument metadata • In contrast to WMO Pub. 47 VOS metadata, which have been systematically gathered and published since 1955 • ETMC should follow the lead proposed at DBCP-30, and encourage member countries to take action to remedy this situation, whereby wave archive agencies are encouraged to check their records, and make sure that the historical and present wave buoy metadata (and data) are made available to international archives (e.g. ICOADS) in a suitable exchange format such as that recently developed by the DBCP Task Team on Moored Buoys (TT-MB).

  21. Alternate Approach • Better idea technologically now might be to not extract data, but use pointers to the extreme events within larger archive(s) (UIDs?) • Why?: Studies of extreme events will logically lead to the desire for availability of surrounding meteorological reports etc. • Concern? Again making the concept too complicated and achieving little.

  22. Potential Role for ICOADS • ICOADS could serve as a host/repository for all measured (i.e. in situ) wave data • EWDS could then be routinely generated from a single consolidated data source • Countries could submit all measured wave data (not just EWDS) to ICOADS, possibly via WOD • IMMA format would need to be improved to avoid reducing resolution • Metadata would be even more of an issue since this is key to ICOADS • Version control would be critical • National archive of submitting country would remain as official archive • E.g., discrepancies remain between the official NCEI/NODC wave archive and the more frequently used NDBC data set • How would satellite altimeter wave information be included? • Noting the issues surrounding sustainability of satellite archive

  23. Future Options for the future of the EWDS could include, among others: • discontinuing it 2) actively promoting the database to other countries with substantial measured wave archives, and obtaining a commitment from them to scan their archived data annually and provide the appropriate data, and metadata, to the hosting agency 3) deferring further consideration until after JCOMM-5 (fall 2017) when the metadata base may be more complete 4) taking a different approach such as having specific identifiers in wave data within ICOADS denoting an extreme event, as defined in the EWDS context, bearing in mind that any added complexity would likely take us back to the pre-JCOMM-4 state

  24. TRUTH GROUND TRUTH Thank you! Courtesy Don Resio

  25. Summary • We have the Phase I dataset in hand, but what now? • Future updates/maintenance may be problematic, since EWDS contains limited extracts from fragmented national holdings (or other specialized archives, e.g. satellite, commercial) • Instrument metadata of historical buoy (and rig/platform) is of crucial importance • Requirements broader than waves – all variables • Thus integration into ICOADS is probably the best solution • Creation of an integrated in situ measured wave dataset would probably have many benefits internationally, e.g. facilitating use, forming manageable input to ICOADS • Improvements overdue in ICOADS wave fields • If wave/swell data were better integrated into ICOADS, the flow of those measurements (and visual observations) could be monitored more effectively • Initial step: develop inventory of buoy/other wave arrays not presently represented in ICOADS, versus those in ICOADS?

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