The GOCE User Toolbox GUT Demo Presentation. Salvatore Dinardo

Transcription

1 The GOCE User Toolbox GUT Demo Presentation Salvatore Dinardo

2 GUT: What Is That? GUT is a toolkit to facilitate the use, viewing and post-processing processing of GOCE Level 2 data products, applicable in the fields of geodesy, oceanography and solid Earth physics. -- Command-Line tool -- Fully open source software under GNU GPL license. -- Written in C++ -- Running under Windows, Linux, Mac OS -- Current Version NetCDF as internal/external storage format of the results -- Modular, Extendible, Flexible to user customizations

3 GUT: some numbers First Public Release of GUT on April 2009 (right after GOCE launch) Second Public Release of GUT on April 2011 (at fourth GOCE Workshop)..actually on line!!! The Current Project will end November 2011 after a half-year phase of maintenance and user support Country Downloads 280 Downloaders in one year of download monitoring Most from China, USA and EU but also from developing countries as Brazil, India, Colombia, Venezuela, Indonesia and North-Africa Around 30 Downloaders of GUT 2 after 20 hours of release 2 pubblication China 36 USA 26 UK 25 Brazil 15 Italy 12 Spain 11 Germany 11 India 11 France 10

4 GUT: How Does It Work? In order to operate, GUT performs a series of processing steps as stated in external XML files called work-flows. Basically, a work-flow is the definition file of the desired processing chain. Inside the workflows, these processing steps are defined by means of the processing units and connections between them. In processing units, the basic algorithms of GUT are encapsulated and the connections assemble these units together in order to form a complete processing flow (work-flow) if structurally valid.

5 Each unit obtains data at its inputs, processes this data and publishes any results at its outputs each work-flow structure can be visualized inside GUT to analyze its internal working <workflow> <units> <CmdLineArgInputFileName name="infile" /> <CmdLineArgReferenceEllipsoid name="re" /> <CmdLineArgDegreeAndOrder name="degreeandorder" /> <CmdLineArgTideSystem name="tidesystem" /> <CreateReferenceEllipsoid name="defaultre" /> <SphericalHarmonicPotentialImport name="datashp" /> <ChangePotentialDegreeAndOrder name="degordsetshp" /> <ChangePotentialTideSystem name="tidesetshp" /> <GridFunctionGeoidHeight name="geoidheight" /> <GridFunctionExport name="export" /> </units> <connection> <socket unit="infile" port="outfilename" /> <plug unit="datashp" port="infilename" /> </connection> <connection> <socket unit="defaultre" port="outreferenceellipsoid" /> <plug unit="re" port="inreferenceellipsoid" /> </connection>.. </workflow>

6 GUT offers to users a portfolio of more than 60 prebuilt workflows for the more general user tasks in the fields of Geodesy and Oceanography. The workflows are located in the folder workflow at GUT main directory level. The workflow can be invocated by GUT command-line and each one comes with a scope description and syntax. The portfolio can be extended by users, placing additional user-made workflows in workflow folder and that gives high flexibility to GUT GUT: WorkFlow PortFolio

7 GUT v1: What Does It Do? GUTv1 was developed with the built-in ability to: Compute geoid height surface at a chosen maximum degree/order over specified grid or transect. Compute the gravitational/gravity potential, gravity magnitude on the surface of the terrain for a range of maximum degree/order. Compute gravity anomalies, height anomalies and vertical deflections on the surface of the terrain for a range of maximum degree/order over a specified grid or transect. Compute the spherical harmonic expansion of a gridded field. Compute a gridded field from its spherical harmonic expansion. Compute the ocean s mean dynamic topography and the geostrophic zonal/meridional velocities, with the option of isotropic filtering in the spatial or spectral domains over a grid or transect. Transform data between different ellipsoids and tide-systems. Mask/Flag Land regions according an input Land/Sea Mask. Translate a gridded surface to a different grid. Interpolate a grid surface on an arbitrary track

8 GUT: Input/Output Current Supported Data Products in Input L2 GOCE Dataset (EGM_GOC_2 only, HDR/DBL pair, both needed) NETCDF (CF 1.2 Convention Adopted) ASCII GRAVSOFT (Only Grid and Point List format ) ASCII ICGEM (Only Spherical Harmonics Format ) Current Provided Data Products in Output NETCDF (CF 1.2 Convention Adopted) ASCII GRAVSOFT (Only Grid Format) KML wrapper file (Only Grid Format) TIFF image file (Only Grid format) CF (Climate and Forecast)-Convention has been adopted for variable and attribute names, when applicable. NetCDF provides efficient, cross-platform binary storage. The support to ASCII format has been augmented

9 GUT v2: What is New? GUTv2 augments the release v1 with the following features: Support for ICGEM Format Support for multi-data netcdf Support for automatic conversion between scientific units (UDUNITS) Anisotropic spatial filtering over grid or transect Grid translation by bicubic spline interpolation Removal of scalar bias from a grid/transect Adjustment of geoid heights in spectral domain by height correction terms Calculation of geostrophic velocities in magnitude and direction Handling of time-system attribute for time-varying surfaces Handling of command history Enhancement of the statistic tools Improved Compatibility with BRAT

10 GUT: Next release The release 2.1 is planned to go out shortly with new features and dataset: Release 2 of the Spacewise Solution More support to Solid Earth Community (Bougeur Anomaly Workflow) Update of some MSS/MDT models Executable Utility to compute errors map and error covariances map of the gravity field and geostrophic surface currents from GOCE Gravity Model Variance/Covariance Matrices Minor Bugs Fixing

11 GUT Official Web Site It s the Showcase for the all activities related to GUT

12 User Survey On going!!! Fast Reply User-Support Desk Frequent Asked Questions Section

13 GUT: Data Viewer Even if the data can be visualized by any third-party plotting tool, GUT includes the BRAT (Basic Radar Altimeter Toolbox) Display as Official Data Viewer by default in the GUT Package and anyway is freely available at: A alternative viewer can be Google Earth, exporting the data in KML format

14 GUT: Data Package The last released GOCE HPF Gravity Model Solutions (actually Release 2 7 months of acquisition) The most advanced Mean Sea Surface and Mean Dynamic Topography models (DTU10 and CLS10) at low and high resolution The Best GOCE-alternative Gravity Field Model in ICGEM format (EIGEN-5C) Altimetry-Corrected Digital Elevation Model (Bathymetry/MSS over seas) Land/Sea Mask One year (2007) of weekly maps of multi-missions Sea Level Anomalies

15 GUT: Data Structure Lat field Lon field Surface Field Coordinate System

16 The Tutorial is a Getting Started guide. It represents the very first resource which a novel GUT user should refer to, approaching the tool. More than 25 Use Cases explained step by step with commands to be typed on the command-line. All subjects covered (file ingestion, variables calculation, data exporting) and new workflows are proposed from scratch and explained how to be built. It is online and in the GUT package. GUT: Tutorial

17 GUT: Let s start it!! How to start up GUT -- Version -- Workflows List How to request help in GUT -- Help -- Workflow Manual -- Verbosity How to execute a workflow usage: gut [options] [<workflow> [...]] run-mode option : --help, --version, --workflows, --dot, --man, --test verbosity level : --quiet, --v, --vv, --vvv, --vvvv The primary run-mode is for data-processing via a specific work-flow flow. The arguments to be provided are depending on the content of the work-flow, but at least the name of a work-flow must be supplied to locate a specific work-flow definition file. Any additional command-line arguments are supplied in -key value pairs. How to validate a workflow --Test -- Dot

18 Geodesy Applications In GUT The first application field of GUT is geodesy. In this field, what user can do by GUT built-in workflows is: Calculate the geoid height surface from GOCE model or ICGEM models at chosen grid range, grid density and spatial resolution Calculate the gravity magnitude, gravity/gravitational potential from GOCE model or ICGEM models at chosen grid range, grid density and spatial resolution Adjust the geoid height surface by height correction terms Transform the geoid height gridded surface in its spherical harmonics components Remove from geoid surface any rigid bias Filter the geoid surface at desired scale length by standard filter kernels

19 Geoid Height Surface in GUT The first utilization example of GUT utilization is the calculation of Geoid Height from GOCE L2 Spherical Harmonics. The workflow (WF) to call is geoidheight_gf. This WF extracts a set of spherical harmonic potential coefficients from input file and calculate the height of the Geoid on a chosen grid with a specified expansion of the geopotential. The mandatory argument of the WF is the one relative to: -Input File Ingestion [-InFile] The optional arguments of the WF are the ones relative to: -Output File Naming: [-OutFile] -Grid Definition (3 ways): [-R, -I, -Ellipse], [-Gf], [-Af] -Scale Length (3 ways): [-DO], [-Dkm],[-Ddeg] -Tide-System Definition: [-T] Example: We can calculate geoid from GOCE and EIGEN-5c and make differences and calculate statistics of differences

20 Geoid Height Correction in GUT The calculated geoid height may be requested to be corrected for errors. The first workflow (WF) to call is geoidheightcorrection_gf. This WF extract a set of spherical harmonic potential coefficients from file and calculate the height of the geoid on a chosen Grid with a specified expansion of the geopotential. Moreover, a set of height correction terms is extracted from a file in the form of spherical harmonic coefficients and added to the geoid heights The mandatory argument of the WF is the one relative to: -Input File Ingestion [-InFile] -Input Correction File Ingestion [-InFileCorr] The optional arguments of the WF are the ones relative to: -Output File Naming: [-OutFile] -Grid Definition (3 ways): [-R, -I, -Ellipse], [-Gf], [-Af] -Scale Length (3 ways): [-DO], [-Dkm],[-Ddeg] -Tide-System Definition: [-T] Example: We can calculate and correct geoid from EGM96 SPH and remove 53 cm bias

21 Geoid ASCII Dump in GUT The calculated geoid height may be requested to be corrected for errors. The first workflow (WF) to call is geoidheightcorrection_gf. This WF export a Grid Function in GRAVSOFT grid format The mandatory argument of the WF is the one relative to: -Input File Ingestion [-InFile]

22 Solid Earth Applications In GUT The second application field of GUT is Solid-Earth. In this field, what user can do by GUT built-in workflows is: Calculate the gravity anomaly at the terrain surface from GOCE model or ICGEM models at chosen grid range, grid density and spatial resolution Calculate the height anomaly at the terrain surface from GOCE model or ICGEM models at chosen grid range, grid density and spatial resolution Calculate the vertical deflections at the terrain surface from GOCE model or ICGEM models at chosen grid range, grid density and spatial resolution Calculate the Bougeur Anomaly from GOCE model or ICGEM models at chosen grid range, grid density and spatial resolution ( as from release 2.1)

23 GA In GUT The first utilization example of GUT utilization in solid earth is the gravity anomaly from GOCE L2 Spherical Harmonics. The workflow (WF) to call is geoidheight_gf. This WF extract a set of spherical harmonic potential coefficients (and GM, R, tide system) from file and calculate the gravity anomaly (free air anomaly) on a chosen Grid with a specified expansion of the geopotential. The mandatory argument of the WF is the one relative to: -Input File Ingestion [-InFile] The optional arguments of the WF are the ones relative to: -Output File Naming: [-OutFile] -Grid Definition (3 ways): [-R, -I, -Ellipse], [-Gf], [-Af] -Scale Length (3 ways): [-DO], [-Dkm],[-Ddeg] -Tide-System Definition: [-T] - Terrain Surface Elevation Model: [-InDemFile] Example: We can calculate the gravity anomaly over alps

24 Oceanography Applications In GUT The third application field of GUT is oceanography. In this field, what user can do by GUT built-in workflows is: Calculate Satellite-only Absolute Dynamic Topography (SLA+MDT) Calculate Satellite-only Mean Dynamic topography (Spectral and Spatial Domain) (MSS-GEOID) Calculate the absolute geostrophic velocities in zonal and meridional components or in speed and direction Calculate combined Mean Dynamic Topography with remove-restore tecnique (A/B)

25 Direct MDTS In GUT The steps to follow to calculate the mean dynamic topography in spatial domain are : ogrid Adaption beetwen Geoid and MSS osubtraction of Geoid from MSS omasking the Difference ofiltering in space domain (default not applied) The mandatory argument of the WF is the one relative to: Input SHP File Ingestion [-InShpFile ] The optional arguments of the WF are the ones relative to: -Output File Naming: [-OutFile] -Grid Definition (3 ways): [-R, -I, -Ellipse], [-Gf], [-Af] -Scale Length Definition (3 ways): [-DO], [-Dkm],[-Ddeg] -Filter Definition: [-Fx scale length], (typical values 1 deg, 2 deg, that is around 200 km, 400 km for truncated gaussian) -MASK Definition: [-Substitute], [-Thr],[-Op] -Input Mask File Ingestion: [-InLsmFile ] -Input SSH File Ingestion: [-- InSshFile ]

26 Filtering In GUT Spatial filtering of a Grid Function is a convolution on the sphere. For each point, P of Grid, the result is formed by a weighted sum of the data at all points, Q, in the vicinity of P. The weights are defined by a filter kernel and are based on the spherical distance between P and Q. where f Q is the value of the Grid Function at Q, w is the kernel weight function and α P,Q, is the spherical distance between P and Q. All filter kernels are characterized by a scale length. The precise shape and the range of influence of each kernel is based on the scale length

27 Masking In GUT The Masking produces a Grid Function that is effectively a source Grid Function with selected point replaced with a replacement value. The points where the substitution is made are determined by comparison with a second Grid Function (MASK) that has the same associated Grid as the source. A every point in the source Grid Function the substitution is made if a comparison of the corresponding mask value with a threshold if logically true The algorithm supports a variety of comparison operators (see table) where m is the mask value, T is the Threshold, S is the Substitution value, op is the comparison operator and f D and f S are the destination and source Grid Function values respectively Application of this processing unit can be: omask-out land regions by substitution of the invalid value oachieve an invalid-free Grid Function by substituting zeros.

28 GSV In GUT From the Absolute Dynamic Topography, the absolute geostrophic currents velocities can be calculated as: not possible recover g currents near the equator f RE (geostrophy does not hold there) f u v f 2 sin g R sin E where g is the local gravity, R E is the local Earth Radius, is the geocentric latitude and φthe geodetic latitude, the longitude, the ADT, the Earth rotation rate The derivates are approximated by finite differences. Velocities at locations in the output close to the equator are NaN Geostrophy means balance between pressure gradient and Coriolis force. geostrophic current flows perpendicular to the two forces that balance to allow this steady flow p s 1 ( ) 1 ( g ) x x fv

29 GSV In GUT The workflows (WF) to call is gsvdirectionspeed_gf This WF computes the direction/magnitude of the geostrophic velocity from a dynamic topography Grid Function The mandatory argument of the WF is the one relative to: -Input File Ingestion [-InFile] The optional arguments of the WF are the one relative to: -Physical quantity to use: [-PQ] -Ellipsoid Definition: [-Ellipse] -Equatorial Margin Definition: [-EqMargin] -Output File Name Definition: [-OutFile]

30 Spatial MDTC In GUT The MDTC work-flow is not part of the standard GUT work-flow portfolio. It has been added by M.H. Rio as personal contribution The MDTC calculated by remove/restore (type A) is defined as: GOCE-only MDT will thus have a centimetric accuracy at a 100 km resolution. In some areas of the world ocean, as coastal areas, straits, semi-enclosed seas such, the MDT is expected to contain signals at shorter spatial scales. In this context, one may want to compute a MDT containing spatial scales not resolved by the Satellite-only MDT. This may be done for instance by completing the Satellite-only MDT with short scales MDT information from other, higher resolution MDT sources (hereafter called the a-priori MDT), through a so-called remove-restore methodology. In this method, first, a Satellite-only solution is computed using the previous use case. Then the high resolution a-priori MDT is filtered using the same filter than for the Satelliteonly MDT computation. Residuals (Apriori MDT minus filtered Apriori MDT) are then added to the Satellite-only MDT

31 Spatial MDTC In GUT The workflows (WF) to call is remove_restore_gf. This WF combines a filtered dynamic topography Grid Function computed from a geopotential and a sea surface height (SSH) to the short scales of an apriori high resolution MDT. A spatial filter may be applied to the masked dynamic topography. The same filter is applied to the apriori MDT and the residuals (A priori MDT minus filtered apriori MDT) is then added to the filtered MDT The mandatory argument of the WF is the ones relative to: -Input SHP File Ingestion: [-InFile] -Input AMDT File Ingestion: [-InFile] -Input MSS File Ingestion: [-InFile] -Input LSM File Ingestion: [-InLsmFile] The optional arguments of the WF are the ones relative to: -Output File Naming: [-OutFile] -Grid Definition (3 ways): [-R, -I, -Ellipse], [-Gf], [-Af] -Scale Length (3 ways): [-DO], [-Dkm],[-Ddeg] -Tide-System Definition: [-T] -Filter Definition: [-Fx scale length] -MASK Definition: [-Substitute], [-Thr],[-Op]

32 THANKS for Your Attention For any questions: