AVSET is coming!

[rdale]

This was mentioned back in http://stormtrack.org/forum/showthread.php?t=22328&highlight=avset

http://www.roc.noaa.gov/wsr88d/NNOW/AVSET.aspx

http://www.roc.noaa.gov/wsr88d/NewRadarTechnology/NewTechDefault.aspx

Testing starts this summer!

THE NWS IS PLANNING AN OPERATIONAL FIELD TEST OF THE AUTOMATED VOLUME SCAN EVALUATION AND TERMINATION /AVSET/ ALGORITHM AT EIGHT WEATHER SURVEILLANCE RADAR- 1988...DOPPLER /WSR-88D/ BUILD 12 RADAR PRODUCT GENERATOR FIELD SITES STARTING NO EARLIER THAN JULY 15 2010 AND ENDING JANUARY 31 2011. THE PURPOSE OF THE TEST IS TO ENSURE AVSET FUNCTIONALITY INTEGRATES INTO WSR-88D FIELD OPERATIONS. IF THE PROPOSED TEST IS APPROVED...THE TEST SITES WILL ISSUE A FREE TEXT MESSAGE IN ADVANCE OF USING AVSET THE FIRST TIME.

THE PROPOSED WSR-88 AVSET OPERATIONAL TEST SITES ARE:

KCCX STATE COLLEGE PA
KEMX TUCSON AZ
KGGW GLASGOW MT
KGLD GOODLAND KS
KIND INDIANAPOLIS IN
KLWX STERLING VA
KMLB MELBOURNE FL
KTLX OKLAHOMA CITY OK

AVSET HAS BEEN DEVELOPED TO MEET WSR-88D AGENCY REQUIREMENTS FOR FASTER VOLUME COVERAGE PATTERN /VCP/ UPDATES...ESPECIALLY IN SEVERE WEATHER SITUATIONS. THE BASIC PREMISE OF THE AVSET FUNCTION IS TO TERMINATE A VOLUME SCAN AFTER THE WSR-88D HAS SCANNED ALL OF THE ELEVATIONS WITH IMPORTANT RETURNS. THE NET EFFECT OF AVSET IS TO SHORTEN THE ELAPSED TIME BETWEEN DATA COLLECTION ON LOW ELEVATION ANGLES. WHEN AVSET IS OPERATING...THE VCP NUMBER DOES NOT CHANGE... THE ELEVATION ANGLES EXECUTED BEFORE THE TERMINATION OF THE VCP DO NOT CHANGE...AND VOLUMETRIC PRODUCTS ARE PRODUCED. THE AVSET FUNCTION:

- EVALUATES THE RETURN ON EACH ELEVATION ABOVE 5 DEG AND TERMINATES THE VCP IF THE AREAL COVERAGE THRESHOLDS ARE NOT MET.

- SHORTENS THE ELAPSED TIME BETWEEN DATA COLLECTION ON LOW- ELEVATION ANGLES AND GENERATION OF VOLUME-BASED PRODUCTS DURING PERIODS WHEN LITTLE OR NO DATA ARE AVAILABLE ON HIGHER TILTS.

- RESULTS IN FASTER VCP UPDATES WITHOUT IMPACTING THE QUALITY AND ACCURACY OF THE BASE DATA ESTIMATES.

DURING THE TEST PERIOD...SITE OPERATORS WILL BE ASKED TO USE AVSET AS OFTEN AS THEY WISH. THE DEFAULT STATE OF THE AVSET FUNCTION IS /DISABLED/. THUS OPERATORS MUST MANUALLY ACTIVATE AVSET EACH TIME USE IS DESIRED. AVSET IS AUTOMATICALLY DISABLED WHEN A CLEAR AIR COVERAGE PATTERN...VCP 31 OR VCP32...IS INVOKED.

THE WSR-88D RADAR OPERATIONS CENTER HAS CONDUCTED EXTENSIVE OFF-LINE AVSET TESTING. AVSET DOES NOT ADVERSELY AFFECT NEXRAD AGENCY SYSTEMS AND NWS BELIEVES THERE WILL BE LITTLE OR NO ADVERSE IMPACT OF AVSET ON USER SYSTEMS. HOWEVER AVSET WILL INCREASE NARROWBAND AND LEVEL II COMMUNICATIONS LOADING. SINGLE-SITE NARROWBAND COMMUNICATIONS AND LEVEL II LOADING CAN INCREASE UP TO 30 PERCENT /WORST CASE/ WITH A FAST VCP. USING AVSET IS AN OPERATOR-SELECTABLE OPTION.
THUS THE OVERALL NETWORK-WIDE COMMUNICATIONS INCREASES WILL
BE MUCH LESS THAN THE INDIVIDUAL SITE FIGURES.

 

[Jason Foster]

Cool, two local radars I use for local chases will be used (KLWX primary for DC, and KCCX for northern chases). Wonder how it will be for winter stuff too.

 

[rdale]

Winter stuff is usually in VCP31/32 for the increased sensitivity, and AVSET doesn't work there. I don't think we're that concerned about a 2.5 minute update interval when it comes to flurries falling

 

[Greg Blumberg]

This is very good...taking steps forward to make a "smart" radar. Only problem with it is the fact that all algorithms have difficulties. I'm willing to bet that this will take a lot of testing until something like this is made operational. If it works...then I'm all for it, but only if it works well.

 

[rdale]

Only problem with it is the fact that all algorithms have difficulties.

I'm not sure I follow... The algorithms work on radar returns. AVSET happens when the tilts do not have radar returns.

I'm willing to bet that this will take a lot of testing until something like this is made operational.

Extensive testing has taken place (I'm sure Greg can chime in?) of the scan strategy. Check the last paragraph of my first post -- this is more for testing the data delivery.

 

[rdale]

AVSET has been turned off for the test sites. There is a problem with the precip accumulation algorithms not updating correctly, so they will hold off the test until at least Build 12.1 release later this fall.

 

[Jason Foster]

Winter stuff is usually in VCP31/32 for the increased sensitivity, and AVSET doesn't work there. I don't think we're that concerned about a 2.5 minute update interval when it comes to flurries falling

You have no idea how DC gets when we get "flizzards"...

 

[J Tyler]

Rdale, thanks for keeping us updated on this stuff. Its very interesting, and I would have never known about this test program if you had not posted.

 

[rdale]

AVSET training now online at http://www.wdtb.noaa.gov/buildTraining/Build12-3/player.html

 

[Jeff Duda]

I think AVSET is a good thing, but it's a little disappointing to see that in the best case scenario, the reduction in volume scan time for convective VCPs is still less than 2 minutes, so even still some storm scale features will continue to be missed. Kinda sucks to hear that it will not be available after the initial dual-pol upgrades. But I guess that still gives some sites a year or so (assuming it is being put into use already) before they lose it before they regain it again in build 13.