Doppler on Wheels Retrospective

As many people know, Doppler on Wheels #7 was in Melbourne, FL, from August 31-September 11.  During this time, Florida Tech faculty, students, and DOW operator Alicia took part in a series of Intensive Operation Periods (IOPs) during that time.  The weather supported IOPs on 6 days, Aug. 31, Sep. 4, Sep. 6, Sep. 8, Sep. 9, and Sep. 10.  Each day resulted in an adventure of some sort.

The purpose was for Dr. Lazarus (Dr. L) and his remote sensing students to get in on the act, but Dr. L opened it to graduate students via a special topics course plus any other students who were interested.

Before sharing some of the fun of the IOPs, let's check out DOW #7 first. 

Extended cab truck carrying a giant plate?

 For starters, it's a bit of an odd sight.  The DOW is essentially an International flat bed truck with extensions to the cab and a giant serving platter on a fancy stand at the back of the bed.  Upon further review, we find this dish to be a full radar!  And this is not just any radar.

Now we see it's a radar.

The DOW is equipped with a full radar and mesonet assembly.  So not only can we look at the atmosphere, we can look at the real time conditions at the surface.  These all work in sync with a series of computers to get the fastest possible data in the hands of the meteorologists on board.

A strange but effective little setup.  You will learn what this all is a little later.

Inside the DOW is all sorts of equipment.  The drivers seat is equipped with GPS and a series of switches that I didn't learn the full use of, but one of those switches is for the leveling jacks.  These jacks are important because the radar must be level to work effectively.  Thus with the push of a few [dozen] buttons, the truck can be leveled as needed to ensure accuracy of data collection.  The best way to do this, of course, is to park in a spot that is already near level.

Inside there are computers all over the place.  There is one screen in the passenger's seat plus there are over 10 screens in the cab.  There are two full stations, each equipped with the same sets of screens and hooked up so that each station is actually running from the same computers.  If a person at station #1 changes the radar setting, the person at station #2 will be able to watch the mouse move and click and see the changes.

Unity and order are of the utmost importance here.  The computers must be synced in the correct order, and the operators must be familiar with the computers.  Run-time errors can occur suddenly and mess up the functioning of the whole system because if one system boots out of order, the rest will not work either.

Monitoring screens

There are two monitors at the back of the picture above.  The lower screen tells many things about the DOW's conditions: equipment temperautres, atmospheric conditions, internal conditions, PRF settings, operating frequencies, etc.  This screen is the center of operations and tells the operator if everything is sync.  Keeping things in sync requires an internal wireless-type connection that communicates between the computers; when that connection goes, all of it goes. Thus the operator must always keep an eye on this.  The screen above has two graphs on it because it's an oscilloscope that measures the frequency of the signals.  If you look carefully, you will see two pulses, because the DOW is dual-pol AND dual-frequency!

Real-time operations, but DOW was down this day.

In the picture above, you will see real-time data collection from the final IOP DOW#7 went through during its stay in Melbourne.  On the screen in the center, there is a gray box; this box contains the radar settings.  These settings control the radars scanning operations, with setups possible for 360° scans, PPIs, RHIs, and sector scans of all sorts.  The screen on the right has the radar output, and this data is real time with information showing up on the screen almost instantaneously.

A weatherman's dream

As can be seen, the output is colorful.  On the left, the two screens are showing the full 360° profile of the radar scanning.  The two on the right show elevation scans.  On the top two are regular reflectivity, and the bottom two show velocity.  These screens, however, can be set to output any radar measured quantities the operator wants to see, which varies from situation to situation.  It is important to not that "north" on the radar output is NOT north, it is actually the direction the DOW truck is pointing toward.  Thus, if the truck is pointing east, then radar north is actually east.  Fortunately, there is software to fix this once data is off the truck and in the hands of the meteorologists.

Through the cage

When all else fails, look out the window; or through the porthole in the top of the truck.  Sometimes, especially with little to know visibility to the outside from the cab, the operators just need to know whats coming.  For this, they have a glass dome in the top for observing the surroundings.  Fortunately, there is a Faraday cage around the dome just in case the truck gets hit by lightning.

The transmitter

The transmitter is where the radar signal originates.  Yes, it is a black box made of steel and plywood, but inside that is a mess of electronics (and TWO 400-volt resistors!).  There are switches and knobs on here.  There are two important switches though: for turning the signal on and off.  The only knobs I actually know the functionality of are the frequency settings, because signals must be fine-tuned especially during a large-scale multi-DOW operation where interference can occur.  Scanning is optimum at a range of 50km or less, but the radar can go out to 100km.  This radar operates at higher frequencies (c-band) than standard NWS radars (s-band) because of this shorter range.

Malfunctions frequently happen, so there is strength in numbers.  When there are storms that a full profile is desired on, data from multiple radars can be combined to form a complete picture.  And experiments have been done on snow, pollution, orographic effects, tornadoes, hurricanes, and even fires!

Procedures for the IOPs were simple but needed to be followed carefully.  There would radiosonde launches from campus along with an on-campus rain gauge.  Lidar would be set up near the DOW to get wind profiles.  Then the rain gauge team would go out to a storm outside the DOW's cone of silence and find a storm to deploy the other rain gauges.

The wrong "Cone of Silence"

Now for some stories...

An IOP in Osceola County

First time I personally got to go out on an IOP was Friday, Sep. 4.  The goal for the day was chosen to park the truck in an open section in Deer Park, in eastern Osceola County.  This spot would allow for scans of just about anywhere within the county, and the chase was on!  And thus four people in a Mazda went exploring the backwoods of Osceola County, looking to drop a rain gauge in front of a storm.  Soon, they had picked their storm and went off in search of an open area in the storm's path.

The perfect spot

Rain gauge setup went perfectly and was completed just in time to get the first drops of rainfall.  The meteorologists checked their radars just in time to see the storm go from a nice bright yellow reflectivity into a fractured green reflectivity.  It was an adventure and worth some laughs, although it turned out we were in unfriendly territory.

During the Tuesday, Sep. 8 IOP, the perfect storm was found: a storm so powerful it would eventually require a Severe Thunderstorm Warning from the NWS.  This was perfect for both DOW data collection and transient luminous events (TLEs).  And then the DOW stopped working.  This is unfortunately one of the facts associated with DOW, so we would just have to keep on trying another day!  And the next two days would be fruitful indeed!

Fast forward to Thursday, Sep. 10 and what would be the final IOP.  Prof. Splitt, Camila, and the students going in the DOW started with rain gauge setup in the south part of campus.

Prof. Splitt puts the hammer down while Camila checks that the gauge is level.

And thus it was time to go into the DOW once again (thank you Dr. L for giving me another chance after the debacle on the Tuesday!).  This time there was success as the DOW caught real time formation and orphaning (anvil being shorn off) of pulse storms

Yes, this picture again.

And then when that was all said and done, we got to watch Dr. Weaver test his new piece of equipment, although this will get used more on Indian River Lagoon research.

 

None of this would have happened without the efforts of Dr. L, Prof. Splitt, Angela, and Alicia, the DOW operator.  They expounded much time and energy so that other people could be involved.  Without Dr. L and Prof. Splitt's grit and determination, there would have been no DOW here.

Thanks to every one of you!