Extracting Weather Information from the SPS-48E Radar for US

Navy NOWCAST

Paul R. Harasti, John Cook, Qingyun ZhaoMarine Meteorology Division, Naval Research Laboratory,

Monterey, CA, USA.

Lee J. WagnerAtmospheric Propagation Branch, SPAWAR Systems Center,

San Diego, CA, USA

Cathy Kessinger, Dan Megenhardt, James Pinto, Ben HendricksonResearch Applications Laboratory, National Center for Atmospheric Research,

Boulder, CO, USA

Outline

• Overall Objective• Radar data quality control• Introduction to the SPS-48E• Results of ground test of SPS-48E

(comparison of single volume scan products with WSR-88D data)

• Example of multiple-radar, multiple-volume-scan product (NCAR TITAN storm tracker)

Overall Objective

To provide radar data processing, quality control, fusion with other data, and assimilation into the NRL NOWCAST system and other Navy systems to support tactical decision making in the US military.

US Military radars: SPS-48E, SWR, MetMF(R), SPY-1/TEP

US National Weather Service radars: WSR-88D, future dual-Pol and phased-array radar

Example, NRL-NOWCAST Demonstration using SWR data at the Naval Air Station, Fallon, Nevada, USA

Radar Data Quality Control (QC)

Other issues for radars at-sea: corrections to data gathered on a moving platformcorrection of beam height for AP in marine surface and evaporation ducts creation of an adjustable grid due to the moving platform for multiple volume scan products, such as the NCAR TITAN and several others

Method Ground Clutter

Precip-itation

Insects -Clear Air

Sea Clutter

Noise Birds CPF Artifacts

MIT/LLDQA

X

X

X

X

XNCARREC

X X X X

XNSSL/OUQC

X XPCAQC

X XNRLQC

X

Introduction to the SPS-48E

• Long range, air defense, volume scanning radar onboard US Navy aircraft carriers and large deck amphibious ships

• S-Band, pencil beam, scans electronically in elevation

• Its tactical-military use has been enhanced with a weather extractor computer and a weather data interface card that provide Doppler data at the lowest three tilts and reflectivity data at all elevations

Ground Test of the SPS-48E

• SPS-48E located on US Navy property at Dam Neck, Virginia

• Single-volume scan products derived from the SPS-48E data were compared to the same products from two neighboring WSR-88D units at Dover AFB, New Jersey (KDOX) and Norfolk, Virginia (KAKQ)

• Case study: Precipitation associated with a cold front along the US east coast

VAD Winds

KDOX SPS-48E KAKQ KDOX SPS-48E KAKQ

Example of a Multiple-Radar, Multiple-Volume-Scan Product

• A 3D radar reflectivity mosaic from KDOX, SPS-48E and KAKQ was created from the volume scans at each time

• The mosaic was ingested into the NCAR thunderstorm identification, tracking, analysis and nowcasting (TITAN) software

• TITAN provides short term (0-2 hour) forecasts of storm cells exceeding a minimum size and reflectivity threshold

• TITAN uses an optimization scheme and weighted linear fit to identify and track storms cells, including geometric logic to deal with mergers and splits

TITAN 30-Minute Forecast and Validation

SummaryThe radar products shown in this paper and previous studies have verified the quality and accuracy of the SPS-48E radar data, and also demonstrate the readiness of NRL-NOWCAST to extract valuable weather information from this data for US military operations.

Future Work• Test and select the optimal combination of radar data QC algorithms to remove unwanted echoes and artifacts• Obtain SPS-48E data from an at-sea experiment to develop and test remedies for the QC and gridding of data gathered on a moving platform