Global Multi-Resolution Topography (GMRT) Synthesis. LDEO-NSF supported

Transcription

1 Global Multi-Resolution Topography (GMRT) Synthesis LDEO-NSF supported Suzanne Carbotte, Vicki Ferrini, Justin Coplan, William Ryan, Suzanne O Hara, Kevin Mclain, Frank Nitsche, John Morton, Rose Anne Weissel, Julie Bonczowski

2 GMRT Overview -Multi-resolution synthesis -Grid tiles, entire globe -Access provided to images & gridded compilation -11 resolution levels to 25 m -Dynamically maintained -Mask highlights hi-res data -Attribution to data sources & contributing scientists

3 GMRT Overview Global coverage 100m swath data and grids User experiences seamless transition between resolutions based on chosen zoom level

4 Current global coverage of GMRT m resolution

5 Attribution to original data sources

6 Attribution to original data sources

7 Attribution to original data sources

8 Attribution to original data sources

9 Access to original data sources

10 Access to original data

11 1. Terrestrial Regions GMRT Data Sources SRTM (GMRTV1), ASTER, NED (GMRTV2.0), BEDMAP (Antarctica) 2. Ocean regional scale (resolution levels 1-6, globe to ~800m) Smith and Sandwell V12 IBCAO v2 3.Ocean high resolution (levels 7-11, 400m-100, 25m) Multibeam Swath data from ~500 cruises (either from scientists or NGDC) Contributed grids US and foreign scientists and data centers

12 GMRT Dissemination 1.Client Applications GeoMapApp, Virtual Ocean, Earth Observer (ipad/ipod app) Make custom grids and maps Grids output options: netcdf, ArcGIS, ASCII, Binary, Fledermaus Image output options: BMP, PNG, GeoTiff, KMZ 2. Web tool Create Maps and Grids Make custom grids and maps Image (JPG) and grids (netcdf) for user selected region, both masked and unmasked 3. Web Services OGC Web Map Service KML service

13 Data Description and Documentation 1. Internal data tracking system All source registered within MGDS relational database Swath files linked to source cruises and fully documented with mbinfo Grids documented with gridinfo parameters Data tracking system provides infrastructure for attribution 2. QA/QC of swath data generates log files documenting what was done to data 3. Paper describes GMRT design and methodology Ryan et al., 2009

14 Data QA and Cleaning 1. Automated coarse filtering and assessment using tools based on MBSystem Generates log file including history of filtering and tests performed (parameters and results) Output guides manual inspection and editing process 2. Preliminary gridding of data for assessment in custom GMA View within the context of the compilation Quantitatvie tools for assessment (e.g. profiling, transparency, ability to enhance dynamic range) Ability to quickly identify problematic ping files 3. Data cleaning using MBSystem Tools (e.g. sound velocity, ping editing, etc.)

15 Data QA and Cleaning Bad navigation Noisy outer beams Attitude problems Bad soundings Instrument problems Bad weather Sound velocity Slow speed in turns Quality assessment for grid weighting and resolution

16 MB files GMRT MB Prep Workflow Preprocess & Auto-QA Problems Manual assessment Reprocess Address Problems (MBSystem) No problems Approval Phase Problems Approved Add to tile set

17 Tools for Quality Assessment *Interface can be used for swath data & gridded data

18 Tools for Quality Assessment

19 GMRT Gridding Details 1. Grid Generation per cruise: Extract points from ping files Apply an across-track weighting factor Apply cruise weight factor based on overall quality used for merging cruises into compilation Grid at max resolution declared by data processor Grids/Images rendered for inspection/approval 2. Gridding Process merging into compilation: After approval, cruise merged into compilation using cruise weighting factor No interpolation into lower resolution data Each cruise gets gridded at 100 m If appropriate, cruise also gridded at one other finer resolution Data decimated for coarser levels 3. Tools used: MBSystem and in-house software

20 Grid Generation 1. Evaluation of compilation Visual inspection with quantitative tools (profiles, grid values, dynamic range) 2. Updating compilation New data continually prepared through QA/QC process. After approval, put into queue for periodic merge into compilation If errors found in compilation, cruise/grid can be removed and problems can be addressed 3. Documentation of compilation development Version the grid Tracking system for new data Database for displaying attribution information Announce release of new versions Data DOI

21 Grid Generation What capabilities and functionalities are on your wish list? Improved methodologies for feathering with regional grids Where do you see your efforts going in the future? Gebco100? What issues do you face that complicate your effort? Non-standard data acquisition Foreign datasets Stable funding