high resolution radar data and products over the continental united states
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High resolution radar data and products over the Continental United States. [email protected] National Severe Storms Laboratory Norman OK, USA http://w ww.wdssii.org/. Evolution of WDSS. What products? How often?. Products: Gridded hail products - PowerPoint PPT PresentationTRANSCRIPT
High resolution radar data and products over the Continental United States
[email protected] Severe Storms Laboratory
Norman OK, USAhttp://www.wdssii.org/
April 19, 2023 [email protected] 2
Evolution of WDSS
1993-1998
Single-radar SCIT, MDA, TDA
Now part of RPG
1995-2000
Single-radar with multi-sensor input
NSE inputs
Scheduled for ORPG-8
2003 Multi-radar multi-sensor over regional domain
(1000km x 1000 km)
Gridded products
Shipped to select WFOs
Used in Storm Pred. Center
Product gen. for AWIPS?
2005 Multi-radar multi-sensor over CONUS
CONUS 1km grids
Available on the Internet
Used in SPC
April 19, 2023 [email protected] 3
What products? How often?
Products: Gridded hail products Reflectivity at constant temperature levels and layer averages Low-level and mid-level shear and rotation tracks Short-term forecast fields Lightning Density More …
Spatial Resolution: 0.01 deg x 0.01 deg [x 1km] resolution Approximately 1km x 1km throughout Continental United States. 1km in height
Temporal resolution: 2D reflectivity mosaics every 2 minutes 3D and derived products every 5 minutes
April 19, 2023 [email protected] 4
How does it work?
The process for creating 2D composites: Ingest Level-II radar
data tilt by tilt QC reflectivity data
(Lak06, JAM, review) Create virtual volume
composites Merge composites from
all the CONUS radars (Lak06, WF, accepted)
2nd level of QC -- using satellite and surface temperature data.
April 19, 2023 [email protected] 5
Virtual volume composite
In a traditional composite, Process volume-by-volume. Take maximum of all tilts. Need to wait for end of
volume. In a virtual volume composite:
Process tilt-by-tilt. Keep a running volume. Replace older data each time. Take maximum of most
current tilts. No need to wait for end of
volume scan. A virtual volume provides more
timely data.
at19.5
at0.5
April 19, 2023 [email protected] 6
Why do QC?
On a single-radar product, users may: want to see clear-air
returns. tolerate more clutter tolerate test patterns,
etc. On a multi-radar
product, clutter and clear-air returns are distracting.
April 19, 2023 [email protected] 7
Impact of QC
Left: What we would get if directly combined raw (virtual volume) reflectivity composite data Clear-air return, sun strobes, test patterns
Right: combining QCed virtual volume reflectivity composite The QC is performed radar-by-radar
Takes into account terrain, texture and vertical structure.
With QC’ed compositesraw
April 19, 2023 [email protected] 8
Second level of QC
The radar QC is conservative Doesn’t always remove
non-precipitation echo Especially if it is
biological i.e. moving. A second level of QC
looks at satellite and surface temperature and retains echo where there is likely to be clouds.
Bad data
(bloom)
No clouds
April 19, 2023 [email protected] 9
What do we do with the composite?
The 2D radar mosaic is created every 2 minutes at 1km resolution. Converted to Grib2 and sent to the SPC. Put on the Internet:
Snapshots with map background Converted to Geotiff
Loadable with Google Earth or any GIS software. Google Earth does real-time loading Talk in IIPS on Tuesday
http://wdssii.nssl.noaa.gov Not 24x7
The software is licensed by some private companies They run it on their own machines. They take care of 24x7 reliability.
April 19, 2023 [email protected] 10
2D vs 3D
The 2D composite is cheap to create
5 dual-Xeon machines with 6 GB RAM
But always provides an underestimate of true values.
Need to compute in 3D Height of dBZ value important! Can incorporate NSE
information by height A lot more products!
The 3D products need: 5 dual-Xeon with 6 GB RAM 2 dual-Xeon with 16 GB RAM 64-bit architecture
composite from 2D: 45 dBZ composite from 3D: 50 dBZ
April 19, 2023 [email protected] 11
The 3D flow
Not just reflectivity.
Compute shear (Smith05) and low-level shear.
Process lightning
April 19, 2023 [email protected] 12
3D processing
Combine QC’ed reflectivity in 3D
Combine AzShear in 3D
Compute hail diagnosis and layer averages.
Compute storm motion from composite.
Use it to advect storms for short-term forecast.
April 19, 2023 [email protected] 13
Example products
Extracted from the real-time generation on Jan. 11, 2006The day I created this presentation!We haven’t run the CONUS system in
Spring yet, so the severe weather products may be underwhelming.
April 19, 2023 [email protected] 14
Reflectivity products
Composite from 2D Composite from 3D
Height of Max Ref Which radars?
April 19, 2023 [email protected] 15
Azimuthal shear products
Azimuthal shear 0-3km MSL 30 minute rotation tracks
April 19, 2023 [email protected] 16
Severe weather diagnosis
Reflectivity at temp. levels
Echo top (18 dBZ)
VIL
Convection
Also:
Probability of Severe Hail
Maximum Expected Hail Size
VIL_Density
VIL_of_the_day
Other echo top dBZ levels
April 19, 2023 [email protected] 17
Short-term forecast
Reflectivity at T=0 Clusters
Reflectivity at T=30 (forecast) Southward motion
April 19, 2023 [email protected] 18
Precipitation estimates
Just the 88D algorithm on CONUS Uses hybrid scan reflectivity Convective/stratiform segregration
based on presence of hail 88D Z/R relationships.
Not multi-sensor QPESUMS-II under development
at NSSL.
Ref closest to ground
2hr precip accum
Instantaneous precip rate
April 19, 2023 [email protected] 19
What do we do with these products?
The 3D products are created every 5 minutes 1km resolution (0.01deg x 0.01deg x 1km) Converted to Grib2 and sent to the SPC. Put on the Internet (not all of them):
Snapshots with map background Converted to Geotiff
Loadable with Google Earth or any GIS software. Google Earth does real-time loading Talk in IIPS on Tuesday
http://wdssii.nssl.noaa.gov
Looking for the NWS to pick this up!