Glossary Definitions

Glossary of terms, data formats, and programs, related to ELDORA.

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Do
Contains the distance from the radar to the center of each recorded data cell.

Data Formats and Files

CEDRIC 'pure' Data
The 'pure' binary format for CEDRIC data. This is the output format for both REORDER and CEDRIC. It is a simple gridded data format, developed by Carl Mohr and Jay Miller at the Mesoscale & Microscale Meteorology Division of NCAR. Please refer to Appendix D of the CEDRIC documentation for further information.
CFAC Files
ASCII files contains the navigation corrections and radar pointing angle corrections. Fore and Aft radars each have a CFAC file (they are usually different). For historical reasons, the ground-speed correction is read in via the E-W velocity entry. The roll correction is not used because the error in rotation angle and roll cannot be separated.
DORADE Format
DOppler RAdar Data Exchange Format. Developed by Wen-Chau Lee, Craig Walther, and Richard Oye of EOL for efficiently storing and exchanging airborne and ground-based radar data. Please refer to the Dorade Format Overview for further information.
Dorade Sweep Files
The internal format for the SOLO program. The sweep file format is a variation of the DORADE format, where each individual sweep of the radar beam is stored in its own file. Please refer to the Dorade Format Overview for further information.
GMETA Files
The metafile that is produced by CEDRIC when the GRAPHICS command is invoked. These files can be viewed using idt, which is a product that is part of NCAR graphics.
Ground Echo Files
The Translator generates one ground-echo file (with gde prefix) for fore and aft radars that contain information (INS, pointing angles, reflectivity, and Doppler velocity) for the ground gates selected in each beam that intersects the ground. The ground-echo files will be the input files for the plotscatter program to compute the INS and pointing angle errors.
HRD Format
Radar data format used by the NOAA P-3 tail and lower Fuselage radars. Takes its name from the Hurricane Research Division. Can be translated into DORADE sweep files for use with SOLO.
netCDF Data
NetCDF (network Common Data Form) is an interface for array-oriented data access and a library that provides an implementation of the interface. The netCDF library also defines a machine-independent format for representing scientific data. Together, the interface, library, and format support the creation, access, and sharing of scientific data. The netCDF software was developed at the Unidata Program Center in Boulder, Colorado. Please refer to the netCDF home page for further information on the format or the RAF Data Catalog for further information on RAF data.
Raw ELDORA Data
ELDORA field format data. This is a variation of the DORADE format where fore and aft beams may be interleaved and unsorted.
Universal Format
The Common Doppler Radar Exchange Format, more commonly referred to as Universal Format (UF). Designed primarily to accomodate data for a single ground-based radar, it lacks some of the descriptor information needed to fully describe ELDORA data.

Airborne Radar Data Software Tools

ADNaCS
NCAR/EOL developed software for calculating navigation corrections. It implements both the THL method and the GRH method for complex terrain, and allows for direct visualization of the correction factor application. It is currently still under development.
CEDRIC
An NCAR/MMM supported mesoscale data analysis program that processes datasets on regular Cartesian and longitude-latitude grids. The analysis options include many numerical operations such as algebraic, filtering, and Doppler radar wind synthesis, both ground-based and airborne, as well as graphical operations. Several REMAPpings (interpolations) are possible: XYE --> XYZ, LLE--> LLZ, XYE <--> LLE, and XYZ <--> LLZ, where XY (LL) is a regular Cartesian (longitude-latitude) grid. Z (E) refers to a constant height (elevation angle) surface. CEDRIC uses its own self-describing, binary format as well as the network Common Data Format (netCDF) that was developed by NASA and UCAR's UNIDATA. CEDRIC can ingest Mudras data (pure format) from Reorder or Sprint interpolation software. The synthesized data can be saved in Mudras or Netcdf format for further processing. Graphical output is saved as gmeta file and can be viewed using NCAR IDT software. Please refer to the CEDRIC documentation for further information.
Data Translator (xltrs)
An NCAR/EOL supported software that converts several popular radar data formats (e.g., UF, HRD, ELDORA field) into sweep files (the internal format for the editing software, SOLO) and converts edited sweep files into UF and DORADE format for further processing. The translator has other functions such as generating the ground-echo files for navigation corrections and merging updated information (e.g., RAF flight-level data and correction factors). Please refer to the translator documentation for further information.
DoppRL
Fortran program developed by Brian Bosart at UCLA to fine-tuning navigation corrections on a leg-by-leg basis using the BLW method.
GRID2PS
An NCAR/EOL developed software that produced publication quality 2-D vector and contour plots in PostScript form. Grid2PS can ingest Mudras data and produce horizontal and/or vertical cross-sections. Multiple panels of plots can be arranged on a single page. Please refer to the grid2ps documentation for further information.
IDT
idt provides a graphical user interface to the NCAR View interactive metafile translator ictrans. idt supports a subset of the ictrans command interface. Please refer to the idt man page for further information
Plotscatter
An NCAR/EOL supported program that computes the INS and radar pointing angle errors. The framework of the plotscatter program is documented in Testud et al. (1995). The plotscatter program output suggestions on possible errors/biases on 8 parameters. Users need to manually update these corrections in the CFAC files. New ground-echo files using the updated navigation corrections (CFAC files). The final corrections are obtained via an iterative process until the ground is flat and not moving. A batch version of the plotscatter program (driven by Perl script) is available to automate the entire process. Please refer to the plotscatter documentation for further information.
REORDER
REORDER is a program that transforms radar data from radar space to cartesian space or cylindrical (coplane) space. The data can then be ingested into CEDRIC for synthesis. Please refer to the REORDER documentation for further information.
SOLO
An NCAR/EOL supported radar/lidar data display and editing software. SOLO is a X-window based interactive software that replaced the RDSS software in 1993. Please refer to the SOLO documentation for further information.
SPRINT
Sprint is an NCAR/MMM program to interpolate radar measurements taken at spherical coordinates (range, azimuth, and elevation) to regularly-spaced Cartesian or longitude-latitude grids, in either constant height or constant elevation angle surfaces. It accepts radar data in any of the EOL field, univeral, DORADE, or NEXRAD Level II formats. SPRINT outputs interpolated data in pure binary format readable by CEDRIC. A description of the CEDRIC binary format can be found in Appendix D of the documentation for SPRINT or CEDRIC. Data from PPI scans can be interpolated to Cartesian or longitude-latitude grids, either at constant height or constant elevation angle surfaces. Both airborne helical scans and constant-azimuth (RHI) scans from ground-based radars are only interpolated to Cartesian grids (X, Y, and Z)
TuningFork
IDL tool for fine-tuning navigation corrections on a leg-by-leg basis using the ETHL method.
WindInterpolate & Wind3_fill
These complementary programs developed by John Gamache at NOAA's Hurricane Research Division (HRD) provide interpolation and synthesis for multiple Doppler datasets. Wind3_fill is a fully three-dimensional wind solver that includes the continuity equation and a small amount of filtering of the solution when determining the cost function.

Data Elements

Cell
A data point recorded on the recording media. It can be a gate or an average of several gates.
Gate
A sampling element of the radar itself.
Ray
A logical unit of data which contains all data cells (from a single "radar") taken during a single dwell time.
Sweep
A number of rays with similar characteristics, i.e. rays within a 360 degree rotation, PPI, or RHI.
Volume
A number of sweeps with similar characteristics.

DORADE Format Elements

DORADE Format Cell Range Vector
Contains the distance from the radar to the center of each recorded data cell.
Dorade Format Comment Block
Contains any number of ASCII characters describing or commenting on anything that the generator of the data set feels is appropriate.
DORADE Format Correction Factor Descriptor
Contains the correction factors needed to be applied to various parameters before using them.
DORADE Format Data Ray
Contains information and data of a ray.
DORADE Format Parameter Data Block
Contains the actual data for a single parameter corresponding to those described in the parameter descriptor.
DORADE Format Parameter Descriptor
Contains information describing each parameter.
DORADE Format Platform Info Block
Contains the navigation information for this ray.
DORADE Format Ray Info Block
Contains unique information about this ray.
DORADE Format Sensor Descriptor
Contains information defining the particular sensor and its operational parameters.
DORADE Format Sweep Info Block
Contains information unique to this sweep.
DORADE Format Volume Descriptor
Contains a number of descriptors to define the characteristic of the instrumentation(s) and the corresponding parameters.