Attendee 4 (to All):

Hi Sim.


Attendee 5 (to All):

Good morning from North Carolina


Attendee 5 (to All):

Oh, I am the only one here...


To Organizers:

Hello, Brian!


Attendee 5 (to All):

Aha! Good morning Sim :o)


Attendee 4 (to All):

Hi from FSU/COAPS.


Attendee 5 (to All):

Good day Henry, this is Brian in North Carolina


Attendee 4 (to All):

Hi Brian. How are you today?


Attendee 5 (to All):

Not bad. It's rather dreary here - 42 and foggy.


Attendee 5 (to All):

I presume the weather is more interesting in your location?


Attendee 4 (to All):

Ha, its about to get REAL interesting :)


Attendee 5 (to All):

That's what it looked like on radar... if we lose you mid-meeting, we will know why


To Organizers:

I'm not sure you can hear us, can you?


To Organizers:

We are on the phone number.


To Organizers:

We also can't see who the attendees are on the chat.


To Organizers:

The 646 number?


To Organizers:

Nobody else is listed there


Attendee 5 (to All):

Hi Sim! I see your screen...


Attendee 5 (to All):

You are searching... searching for something...


To Organizers:

Great! Whos is attendee 5?


To Organizers:

Nobody can hear me, though, huh?


Attendee 5 (to All):

Hello Ryan!


Attendee 5 (to All):

Getting all sorts of folks on board now...


Attendee 6 (to All):

Hi Brian, Hi Sim. My other meeting was cancelled.


Attendee 5 (to All):

Great to have you on board


Attendee 5 (to All):

How are things Ryan? All well in the frozen north?


To Organizers:

I can't tell who the attendees are?


Attendee 4 (to All):

Sorry Brian, technical challenges here.


Attendee 5 (to All):

Oh?


Attendee 4 (to All):

I think we are OK. Getting audio configured for meeting.


Attendee 5 (to All):

I can see Sim's computer screen, and I can see text messages, but I do not hear yet.


Attendee 5 (to All):

Do you all hear me?


Attendee 4 (to All):

No.


Attendee 4 (to All):

The list says you are 'muted'.


Attendee 4 (to All):

Can you hear me?


Attendee 5 (to All):

I hear nobody


Attendee 4 (to All):

Hmmm...


Attendee 6 (to All):

I do not hear anyone.


Attendee 4 (to All):

Sim can you hear us?


Attendee 5 (to All):

Nothing yet


Attendee 4 (to All):

OK.


To Organizers:

We're trying to figure out the sound.


Attendee 7 (to All):

This is yuanfu from boulder. I hear some pings but no other sound.


Attendee 5 (to All):

I am the same - pings


Attendee 4 (to All):

Same here.


Attendee 5 (to All):

On my list, I only see me and Ryan as 'on' with audio.


Attendee 5 (to All):

And Ryan is muted


Attendee 4 (to All):

I see you are muted too, Brian.


Attendee 5 (to All):

Huh... on mine, it says I am NOT muted


Attendee 6 (to All):

I muted myself so that I do not have any back noise.


Attendee 4 (to All):

Ah, OK.


Attendee 5 (to All):

So nobody can hear anyone else?


Attendee 4 (to All):

Ha, apparently.


To Organizers:

Are you dialed into the 646 number?


To Organizers:

Sorry about the delay


Attendee 4 (to All):

If HRD had a stenographer, they could type in a box on Sim's machine and we could read-along.


Attendee 5 (to All):

On my machine, it says I am "muted by Organizer"


Attendee 6 (to All):

For the people on the phone, can they hear anything?


Attendee 4 (to All):

No.


Attendee 5 (to All):

I see we are trying to 'get help'


Attendee 4 (to All):

Yes.


Ryan Torn (to All):

Yes


Henry Winterbottom (to All):

I still cannot hear anything.


Ryan Torn (to All):

I am here. I just need to reconfigure to talk.


Ryan Torn (to All):

I muted myself so that we don't have audio problems.


Ryan Torn (to All):

Yes. I can hear you Sim.


Brian Etherton (to All):

I hear you too.


Brian Etherton (to All):

We've lost Henry, somehow


Brian Etherton (to All):

Maybe the line of severe weather got there...


To Organizers:

Henry, you can't hear us?


Henry Winterbottom (to All):

No weather yet.


Henry Winterbottom (to All):

tech problems.


To Organizers:

Henry, are the problems on your end?


Ryan Torn (to All):

I muted myself, so the echo should not be coming from me. I will unmute I need to say something.


Brian Etherton (to All):

I am muted


Brian Etherton (to All):

Fire away Sim!


Brian Etherton (to All):

Henry is drying his hair...


Brian Etherton (to All):

Set up is great


Brian Etherton (to All):

Someone is still 'buzzing'


Henry Winterbottom (to All):

OK, problem solved.


Henry Winterbottom (to All):

I can hear you.


Henry Winterbottom (to All):

All.


Ryan Torn (to All):

It appears that user Liou is not muted.


Ryan Torn (to All):

Are you using the same architecture as NMC?


Brian Etherton (to All):

Hi there Munehiko! Would you be able to mute yourself? A lot of 'background noise' is coming through.


Munehiko Yamaguchi (to All):

Brian-san: Sorry for that. Now OK?


Brian Etherton (to Organizers):

Matt Eastin says "Hi"


Brian Etherton (to Organizers):

And then heard "bit-wise reproducibility", and left the room


Ryan Torn (to All):

It is bitwise reproducable on the same computer architecture, but not across different computer architectures.


Ryan Torn (to All):

It is also not bitwise reproducable for different compilers


Ryan Torn (to All):

My experience is that the cumulus/radiation schemes are the source of the non-reproducability.


Ryan Torn (to All):

in WRF-ARW


Brian Etherton (to Organizers):

I agree!


Henry Winterbottom (to All):

I would tend to agree with Ryan,.


Brian Etherton (to All):

I agree Ryan


Henry Winterbottom (to All):

My understanding is that the *main* difference between NMM and ARW is the dynamic core.


Brian Etherton (to All):

Yes yes yes!


Henry Winterbottom (to All):

The physics are independent.


Henry Winterbottom (to All):

So, would not surprise me if we have identical problem.


Henry Winterbottom (to All):

But, I will do some experiments and try to verify this claim.


Brian Etherton (to All):

The physics are indepenent, but they do not interact the same with ARW as with NMM


Henry Winterbottom (to All):

Right.


Brian Etherton (to All):

For example, Ferrier mp 'goes' with NMM better than ARW


Henry Winterbottom (to All):

OK.


Ryan Torn (to All):

But in terms of code, they interact in the same way.


Henry Winterbottom (to All):

OK.


Brian Etherton (to All):

Ryan - I heard that they did not interact in the exact same way.


Henry Winterbottom (to All):

It seems this is an engineering issue as opposed to a physics issue.


Brian Etherton (to All):

That buried in the registry, there were subtle differences.


Brian Etherton (to All):

For example: Ferrier microphysics was not well suited for Dudhia shortwave. Clouds (from Ferrier) ended up having the optical thickness of cement


Ryan Torn (to All):

Could be, but they should be using the same subroutines for the dynamical core to talk to the physics


Brian Etherton (to All):

I am not as wise on the innards of WRF as others... just passing along what I have heard


Ryan Torn (to All):

That problem is a dynamical core problem, not a bitwise reproducable problem


Brian Etherton (to All):

Ah yes... agreed Ryan


Henry Winterbottom (to All):

Heads up to WRF guys, in the ~/WRFV2 subdirectory dyn_nmm exists solve_nmm.F which is the solver for NMM core. In dyn_em exists solve_em.F.


Brian Etherton (to All):

True!


Henry Winterbottom (to All):

Might be worth spending some time to figure out exactly what the differences are.


Brian Etherton (to All):

Henry... ought to be the same story in WRFV3


Henry Winterbottom (to All):

At least this was true in V2 of WRF-ARW.


Ryan Torn (to All):

Right. Those routines call the same physics interfaces though


Brian Etherton (to All):

Yes Sim, we have been going amongst ourselves


Henry Winterbottom (to All):

Ha.


Brian Etherton (to All):

Ah yes... we should be seen and not heard


Brian Etherton (to All):

:o)


Henry Winterbottom (to All):

Sim did a great job.


Henry Winterbottom (to All):

Np!


Brian Etherton (to All):

No problem


Brian Etherton (to All):

We will do something with WRF in North Carolina


Henry Winterbottom (to All):

Brian, what are you doing to initialize the vortex (if anything)?


Brian Etherton (to All):

Probably WRF-ARW... can we even get H-WRF?


Henry Winterbottom (to All):

I have v2 of HWRF souce.


Brian Etherton (to All):

Initialization... a BIG question.


Henry Winterbottom (to All):

I found it at NCEP somewhere.


Brian Etherton (to All):

Hmm... this could be good!


Henry Winterbottom (to All):

Or, perhaps Gopal has the source somewhere.


Brian Etherton (to All):

Can non-NCEP folk get it?


Henry Winterbottom (to All):

I have it.


Henry Winterbottom (to All):

Well, I have the tarball.


Brian Etherton (to All):

That's good enough.


Henry Winterbottom (to All):

I briefly tried to compile.


Henry Winterbottom (to All):

Was unsuccessful, but hadn't invested much time in trying to debug.


Brian Etherton (to All):

Yeah... we have ARW V3... and may well just stick with it


Brian Etherton (to All):

We are leaning towards an initialization much like yours


Brian Etherton (to All):

EnKF and 3DVar only work if the difference between the first guess and the data is 'small'


Brian Etherton (to All):

For 6-hour intervals, in a TC environment, this maybe isn't the case


Ryan Torn (to All):

Depends if you are cycling the DA system over a long period.


Brian Etherton (to All):

My team is sort of interested in all three: newer-bogus, 3D-Var, and EnKF


Henry Winterbottom (to All):

Well, I would be happy to communicate what I have learned.


Brian Etherton (to All):

True Ryan - cycling... AND frequent data collection


Brian Etherton (to All):

We can't let the model drift too far from data.


Brian Etherton (to All):

It seems that the first time you use aircraft radar, it might be a big shock to the system


Ryan Torn (to All):

It is still not clear what data is necessary to set the vortex intensity. This is an open research question.


Brian Etherton (to All):

The model system, that is


Ryan Torn (to All):

Agree that different amounts of data can have a big impact on system.


Henry Winterbottom (to All):

My initial intention was to use the 3d-Var capabilities of ARW. However, for my dissertation question, I needed *more control* over the vortex structure.


Brian Etherton (to All):

So true Ryan, so true!


Henry Winterbottom (to All):

Which was not permitted with 3dvar.


Brian Etherton (to All):

I agree Henry - we will probably try all 3 methods in NC, and then see what we get.


Brian Etherton (to All):

My guess is that the EnKF will do best, better-bogus #2, and 3DVar will do worse


Henry Winterbottom (to All):

I'd be very interested to see your results.


Ryan Torn (to All):

I think you might get different answers for different storms. Henry's method could work well for symmetric storms, but what about severely sheared systems?


Brian Etherton (to All):

That's the thing - we need some sort of bogus scheme that can account for that sort of thing


Brian Etherton (to All):

Not sure what that IS yet...


Henry Winterbottom (to All):

3DVar scares me because your error covariances are derived from 30-day means (PArrish and Derber, 1992) and is closer to geostrophy than anything.


Brian Etherton (to All):

Well... they can be different...


Henry Winterbottom (to All):

Ryan, yes.


Henry Winterbottom (to All):

You are absolutely right.


Brian Etherton (to All):

You can do a 30-day average of inner nests of WRF ARW runs, and use them


Henry Winterbottom (to All):

Sheared systems will perform poorly.


Brian Etherton (to All):

Sheared systems will die off, so nobody cares about them anyway :o)


Ryan Torn (to All):

What about a storm that goes from a sheared environment to a non-sheared environment?


Brian Etherton (to All):

Well... those make a comeback, don't they


Henry Winterbottom (to All):

However, I tried to be vigilante of this and permit ancillary data sets such as Doppler radar u,v winds into the system.


Ryan Torn (to All):

I like the idea of a 30-day mean vortex covariance.


Henry Winterbottom (to All):

I am by no means an expert, just sharing my thoughts.


Brian Etherton (to All):

I can't imagine trying somethign else...


Henry Winterbottom (to All):

I can appreciate the experts insights.


Brian Etherton (to All):

As Henry said, it would be irrelevant


Henry Winterbottom (to All):

When I am done my dissertation, Ryan, I would like to go back and investigate why my initial experiments with 3DVar performed as they did.


Henry Winterbottom (to All):

Future work!?! :)


Brian Etherton (to All):

Sounds like someone wants a post-doc in Albany...


Henry Winterbottom (to All):

Ha.


Ryan Torn (to All):

Future work is always good. Problem #1 is the error covariance length scales and assumptions. Gradient wind balance is necessary.


Henry Winterbottom (to All):

Yes.


Henry Winterbottom (to All):

It isn't clear to me how to get that.


Brian Etherton (to All):

Out now, right?


Brian Etherton (to All):

The DA one closes on April 2nd... I think


Brian Etherton (to All):

ZP-4


Brian Etherton (to All):

Excellent!


Brian Etherton (to All):

Which case?


Henry Winterbottom (to All):

Good day everyone!


Henry Winterbottom (to All):

Take care, everyone.