Basic WCS 2.x MetOcean Profile principles

• MetOceanWCSProfile currently focuses on exposing Numerical Weather Prediction forecasted model data. This data is traditionally encoded in GRIB (or NetCDF) format and often interpreted or used as 2D rectangular-grid fields.These fields have additional metadata attributes which define
  • vertical level of the field (in various vertical level axis types)
  • model run/initialisation/reference time
  • validity of the field (forecast offset relative to model run's time)
• MetOceanWCSProfile tries to aggregate 2D fields which logically belong to each other into more-dimenstional coverage "cubes" with the following principle:
  • Fields with the same vertical axis (e.g. all isobaric level fields) type shall belong to the same "cube". E.g. aramaters at isobaric levels will then form a 4D cube (2 spatial dimensions, 1 vertical isobaric dimension and 1 forecast
• MetOceanWCSProfile makes use of "Coverage Collection" (CovCol) concept to reresent various "sets of cubes":
  • Logical Group-ing of NWP models (e.g. forlders of atmospherics models, ocean models, ...)
  • Defining semancics of NWP model run - each model run is a "simulation", while all runs for a simulation collection (SimulationCollection)
• TBD...

Use cases and examples

This list of use cases and examples was started as part of the Met Ocean WCS plugfest at EGOWS 2017. The page contains the first feedback of trying these services.

Listing available model runs for GFS model

https://ogcie.iblsoft.com/metocean/wcs?SERVICE=WCS&VERSION=2.1.0&REQUEST=GetCapabilities

In the XML response, locate the wcs:Extension element. Each metocean:SimulationCollection subelement represent a different NWP models (e.g. NCEP GFS model) and each it metocean:SimulationMember subelement represents a particular model's run. The time of the run is store in covcoll:referenceTime subelement.

Retrieve 2D fields in GRIB2 format for a specified geograpic area at 500hPa valid at specified absolute time

https://ogcie.iblsoft.com/metocean/wcs?
SERVICE=WCS&VERSION=2.1.0&REQUEST=GetCoverage
&COVERAGEID=GFS_Latest_ISBL
&SUBSET=long,CRS:84(0,20)&SUBSET=lat,CRS:84(30,50)
&SUBSET=t,http://www.opengis.net/def/trs/ISO-8601/0/Gregorian+UTC("2017-06-03T12:00:00Z")
&SUBSET=z,http://codes.wmo.int/grib2/codeflag/4.5/100(500)
&RANGESUBSET=temperature,relative-humidity,wind
&FORMAT=GRIB2
&INTERPOLATION=long(nearest-neighbour)&INTERPOLATION=lat(nearest-neighbour)

This request:

• SUBSET=lat/long perfoms subsetting of the data for specified BBOX in CRS:84
• selects the vertical level to be 500hPa by SUBSET=z...
• selects validity (time) of the requested data by SUBSET=t... you may need to update the absolute time to actual time in the future from the actual time

Retrieve a 2m temperature time series for a specified lat/long point in JSON format for a specified absolute time range

https://ogcie.iblsoft.com/metocean/wcs?
SERVICE=WCS&VERSION=2.1.0&REQUEST=GetCoverage
&COVERAGEID=GFS_Latest_AGL
&SUBSET=long,CRS:84(17.2)&SUBSET=lat,CRS:84(47.2)
&SUBSET=t,http://www.opengis.net/def/trs/ISO-8601/0/Gregorian+UTC("2017-06-03T12:00:00Z","2017-06-06T12:00:00Z")
&SUBSET=z,http://codes.wmo.int/grib2/codeflag/4.5/103(2)
&RANGESUBSET=temperature
&FORMAT=JSON
&INTERPOLATION=long(linear)&INTERPOLATION=lat(linear)

ECMWF - EarthServer2 test service

This services is provided as part of the H2020 EarthServer2 project (May 2015 - April 2018). More information about the ECMWF services can be found at http://earthserver.ecmwf.int .

Example: request capabilities from server

http://earthserver.ecmwf.int/rasdaman/ows?service=WCS&version=2.0.11&request=GetCapabilities

Example: get information about 2m air temperature coverage
http://earthserver.ecmwf.int/rasdaman/ows?service=WCS&version=2.0.11&request=DescribeCoverage&coverageId=temp2m

Example: retrieve a 2D global field of 2m air temperature of 15 December 2013 in GML format
http://earthserver.ecmwf.int/rasdaman/ows?service=WCS&version=2.0.11&request=GetCoverage&coverageId=temp2m&subset=ansi("2013-12-15T00:00")&format=application/gml+xml

Example: retrieve 2m air temperature for a single point of 15 December 2013 in GML format

http://earthserver.ecmwf.int/rasdaman/ows?service=WCS&version=2.0.1&request=GetCoverage&coverageId=temp2m&subset=ansi(%222013-12-15T00:00%22)&format=application/gml+xml&SUBSET=Long,http://localhost:8080/def/crs/EPSG/0/4326(17.2)&SUBSET=Lat,http://localhost:8080/def/crs/EPSG/0/4326(47.2)