Code Updates

Relevant updates listed here will define what product/algorithm was modified, the date and time the update was implemented, and the purpose of the update. Changes listed here are for the NSSL Development system (unless otherwise stated) and date back to January 2014. Code updates prior to January 2014 can be obtained by request.


Mountain Mapper
Date: 21 March 2016     Time: 1632 UTC
Updated PRISM reference data that now includes British Columbia, Canada. Changes were applied starting with the 1200 UTC 21 March 2016 run of Mountain Mapper (DEV).

Dual-Pol Quality Control
Date: 19 November 2015     Time: 1806-1830 UTC
Updated wind farm reference table (includes all sites within 80 km of each radar as of 30 October 2015) and turned on wind farm flag in QC scheme. Resulting gaps in the radar field are addressed in downstream algorithms to generate Seamless Hybrid Scan Reflectivity.

Polar VPR
Date: 6 November 2015     Time: 2030 UTC
Updated to handle the KLGX volume scans, including the extra low-level tilt at approximately 0.2 degrees. The KLGX volume-based VPR did not include the extra low-level tilt prior to this update.

Seamless Hybrid Scan Reflectivity
Date: 6 November 2015     Time: 2030-2240 UTC
Purpose: Updated SHSR algorithm to handle slight variations in Canadian radar elevation angles, smooth gaps in output fields caused by wind farms, non-meteorological clutter, etc., handle missing radar data close to the radar site, and handle KLGX volume scans, which includes an extra low-level tilt.

Q3 Local Gauge Corrected Radar QPE (DEV)
Date: 26 October 2015     Time: 1700 UTC
Purpose: Switch the input gauge data set from a older quality controlled HADS feed (~4000 gauge sites) to a combined quality controlled data set (HADS, NOHRSC, OCS) that has ~10,000 gauge sites.

Canada Radar Quality Control
Date: 13 October 2015     Time: 1940 UTC
Purpose: Increase a clutter filter threshold to avoid the removal of echoes in areas of heavy precipitation.

Canada Radar Quality Control
Date: 6 October 2015     Time: 2015 UTC
Purpose: A new quality control method was implemented to replace the previous version. The new quality controlled radar data feeds into the SHSR products and 3D reflectivity mosaics.

Dual-Pol Quality Control
Date: 2 October 2015     Time: 1615-1805 UTC
Purpose: Implement a bug fix to reduce storm edge erosion, reinstate/add new logic to avoid removing RF signals, and added logic to adjust dBZ thresholding according to the echo height and freezing level.

Dual-Pol Quality Control
Date: 15 September 2015     Time: 1455-1535 UTC
Purpose: Algorithm was updated to reduce storm edge erosion and account for ZDR calibration issues.

MRMS Reflectivity Quality Control
Date: 15 May 2015
Purpose: The Dual-Pol QC became the dominant radar QC algorithm in MRMS. Products impacted include the QPE/Hydro suite, 3D merger of reflectivity, and maximum composite reflectivity. The previous QC algorithm will still feed the Azimuthal Shear and Rotation Tracks products.

Dual-Pol Quality Control
Date: 12 May 2015     Time: 1645-1914 UTC
Purpose: Fix a bug in the sun-spike recovery logic and turn off wind farm flag parameter until seamless hybrid scan reflectivity (SHSR) logic is updated.

Q3 Radar-Only QPE
Date: 29 April 2015     TIme: 2028 UTC
Purpose: Changed 1-hr QPE minimum threshold from 0.127 mm to 0.3 mm in the development product (Q3RAD Dev) to help mitigate false light precipitation until a more physically-based solution is developed.

Dual-Pol Quality Control
Date: 29 April 2015     Time: 1510-1700 UTC
Purpose: Multiple modifications were made to the QC algorithm, including turning off the clean-air VCP check to mitigate the removal of precipitation, reduce over-erosion of precipitation, improved AP clutter removal, better melting layer delineation, reduced removal of hail cores, and better recovery from sun spikes.

Gauge Quality Control
Date: 14 April 2015    Time: 1905 UTC
Purpose: Included new logic for basic QC of gauges where RQI = 0.0 and wet-bulb temperature is above-freezing.

Canada SHSR
Date: 20 March 2015     Time: 1450 UTC
Purpose: Fix missing model sounding input.

Gauge Quality Control
Date: 2 February 2015     Time: 2040 UTC
Purpose: Update power curve parameters for outlier values and RQI values used to compare gauge observations against radar QPE.

Q3 Mountain Mapper
Date: 29 January 2015     Time: 1800 UTC
Purpose: Turn off QC Mask to avoid erroneous removal of precipitation in areas of beam blockage or no radar coverage.

Gauge Quality Control
Date: 3 December 2014     Time: 2120 UTC
Purpose: Update power curve parameters for outlier value assessment.

Dual-Pol Quality Control
Date: 1 July 2014     Time: 2150-0610 UTC
Purpose: Updates to the dual-pol QC algorithm include better mitigation of artifacts left over from bloom clutter removal, reduce the removal of storm edges, reduce the false alarm rate of melting layer identification, and modified logic for backfilling gaps in the reflectivity field.

Surface Precipitation Type
Date: 1 July 2014     Time: 0416 UTC
Purpose: Include more sophisticated logic for identifying regions of convective rain.

Model Remap / Bright Band Analysis
Date: 13 May 2014     Time: 1930 UTC
Purpose: Correction was made to Model Remap to fix problem with the freezing level product.

Model Remap
Date: 12 May 2014     Time: 0330 UTC
Purpose: Updates to the Model Remap algorithm include a switch from 20 km to 13 km RAP isobaric analysis, a switch from nearest neighbor resampling method to a three-point 2D Gaussian smoothing to reduce pixel artifacts, fix a bug with surface wet bulb temperature and Probability of Warm Rain (POWR) calculations, and add a new decision tree ensemble for POWR.

WSR-88D Level II Decoder
Date: 8 May 2014     Time: 1902-1950 UTC
Purpose: Update to decoder settings to allow SAILS scans to enter the MRMS data flow.

Dual-Pol Quality Control
Date: 8 May 2014     Time: 0312-0446 UTC
Purpose: UPdates to correct a bug with RhoHV thresholding that caused severe artificial circular residuals and improved logic to mitigate artificial edges.

Polar Vertical Profile of Reflectivity
Date: 6 May 2014     Time: 2130-0417 UTC
Purpose: Polar VPR logic updated to correctly handle SAILS scans.