SVRCLIPNIU Meteorology

Research record

Publications & citations.

Methodology, Iowa Environmental Mesonet radar-source information, and citation guidance for the current SVRCLIP collection.

Report-centered radar-image methodology

Mean storms: Composites of radar reflectivity images during two decades of severe thunderstorm events

Haberlie, A. M., W. S. Ashley, and M. R. Karpinski, 2021: Mean storms: Composites of radar reflectivity images during two decades of severe thunderstorm events. International Journal of Climatology, 41(S1), E1738–E1756.

https://doi.org/10.1002/joc.6804 ↗

Scope: this paper documents the original report-centered SVRIMG methodology and its historical GridRad-based collection. It does not document the Iowa State radar source, 15-minute sequences, WRF-BCC regridding, or current seven-class SVRCLIP annotation system. Those differences should be stated explicitly in derived work.

Source radar data

Iowa Environmental Mesonet generated NEXRAD mosaics

The current SVRCLIP collection uses the Iowa Environmental Mesonet (IEM) composite_n0r nationwide base-reflectivity mosaic supplied by Iowa State University. The source raster is a two-dimensional 0.01° latitude–longitude composite with reflectivity expressed in dBZ; it is not the three-dimensional GridRad dataset.

The IEM constructs nationwide mosaics from individual NEXRAD radar products and archives them using UTC timestamps. Its official documentation describes a five-minute N0R archive backfilled to 1 January 1995, along with changes in mosaic resolution, clutter suppression, spatial coverage, and upstream radar products. SVRCLIP selects the available 15-minute times used by its processing pipeline.

The IEM documentation also notes that the operational N0R product became a pseudo-composite after the National Weather Service discontinued N0R dissemination in May 2021. Users analyzing long-term changes should consult the IEM product history before treating the source archive as temporally homogeneous.

IEM NEXRAD mosaic documentation ↗ N0R raster and value table ↗

SVRCLIP processing

From the Iowa State mosaic to report-centered sequences

Available IEM fields are regridded with nearest-neighbor interpolation to the approximately 3.75-km WRF-BCC grid. Each tornado report is centered on the nearest WRF-BCC grid cell, and a fixed 136 × 136 domain is extracted at nine 15-minute offsets from −60 through +60 minutes.

The mapped valid-time PNG and evolution GIF are visualization products. Quantitative analysis and machine-learning workflows should use the accompanying NPZ sequences and their geolocation and availability metadata.

Read the full SVRCLIP construction and file-format documentation →

Recommended acknowledgement

Work using the current collection should cite the methodology paper above and acknowledge the radar source, for example:

Radar reflectivity data were obtained from the Iowa State University Iowa Environmental Mesonet generated NEXRAD mosaic archive.

A reference-list entry may identify: Iowa State University, Iowa Environmental Mesonet, “IEM Generated NEXRAD Mosaics,” https://mesonet.agron.iastate.edu/docs/nexrad_mosaic/, with the user’s actual access date.

Using SVRCLIP?

If a publication, thesis, course project, or operational workflow uses SVRCLIP, please contact svr.image@gmail.com so downstream applications can be added to this research record.