Challenging Bill Proenza's QuikSCAT numbers

By: Dr. Jeff Masters , 5:04 PM GMT on July 04, 2007

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A political storm engulfed the National Hurricane Center this week, with a majority of the senior hurricane forecasters calling for Bill Proenza's removal as director. The most visible issue revolved around the extraordinary focus on the aging QuikSCAT satellite. The public argument put forth by Mr. Proenza was that QuikSCAT data was so vital to hurricane track forecasting that without it, track forecast errors would increase significantly, leading to larger warning areas and increased costs for evacuation and emergency planning.

Focus on QuikSCAT--out of proportion?
On March 16th Proenza went public with the QuikSCAT concerns and associated statistics for the first time, stating that "two- and three-day forecasts of a storm's path would be affected. The two-day forecast could be 10 percent worse while the three-day one could be affected up to 16 percent," with the conclusion," that would mean longer stretches of coastline would have to be placed under warnings, and more people than necessary would have to evacuate." As a result of these comments, a perception arose in the public and among lawmakers that without QuikSCAT, NHC would not be able to provide accurate hurricane forecasts. Legislation was hastily introduced into both the House and Senate to provide an immediate replacement for the $375 million satellite.

Proenza's statements raised several questions: 1) Why the focus on track forecast errors in landfalling situations, when QuikSCAT was widely known to be used in intensity forecasting and for tropical cyclones too far at sea to be accessed by the Hurricane Hunters? 2) Could such specific and significant gains in track forecast error truly be attributed to QuikSCAT? Where did these numbers come from, and why was no uncertainty being attached to them?

Since QuikSCAT data became available, starting in 1999, average track errors for 48-hour and 72-hour forecasts have been reduced by 43 miles and 62 miles respectively. Fully one quarter of this improvement was being attributed by Proenza to QuikSCAT. This was an extraordinary performance increase to attribute to one satellite, and seemed doubtful.

We find out where the QuikSCAT numbers came from
In mid-June, Margie Kieper and I asked Proenza to comment on how he got his QuikSCAT numbers. He cited an unpublished study, "A Two Season Impact Study of Four Satellite Data Types and Rawinsonde Data in the NCEP Global Data Assimilation System", by Tom H. Zapotocny, James A. Jung, John F. LeMarshall and Russ E. Treadon. I contacted one of the authors, who informed me that the study was submitted for publication on January 26, 2007, and accepted for publication in the journal Weather and Forecasting on May 23, 2007. It will probably appear in the October-November time frame, according to the publisher. This raises an immediate problem, since only a privileged few are able to read unpublished research. This limits the possibilities for an informed debate on the issue, and basing important policy decisions on unpublished research is thus normally to be avoided. However, making accurate hurricane forecasts is important enough that such considerations can be excused. Proenza didn't give me any details on the study, other than the fact that QuikSCAT data improved 72-hour and 48-hour hurricane track forecasts by 16% and 10% respectively, for a select group of storms from the 2003 hurricane season. One of the authors graciously sent me a copy of the study, though, and after reading it, I had these observations:

1). The study looked at a very limited number of cases over a six-week period during 2003--only 19 cases were available for 72 hour forecasts. The 19 cases were not 19 storms, just 19 separate forecasts from the 4 hurricanes and 2 tropical storms that occurred during the 6-week study period. This sample is too small to draw definitive conclusions about the impact of the QuikSCAT on tropical cyclone forecasts. The two longest-lived storms during the test period were Fabian and Isabel, storms that spent the majority of their lifetimes far away from land. Since the quality of the observing network increases close to land, particulary when reconnaissance data from the Hurricane Hunters is available, it is reasonable to conclude that the impact of the QuikSCAT data for storms within 72 hours of landfall would be less than for the sample as a whole. The study was not primarily designed to study tropical cyclone track accuracy, so there was no separation out of the cases we really care about--storms 72 hours or less from landfall.

2). The study was done with only one model, the GFS. NHC official forecasts make use of several models, including the GFDL, UKMET, NOGAPS and ECMWF. Consequently, a change in the accuracy of a single model will have only a partial effect on NHC official forecast accuracy. As far as I know, there have not been studies done of the impact of QuikSCAT on tropical cyclone forecasts in the GFDL, UKMET or the ECMWF models. Past studies on the impact of dropsonde data from the Hurricane Hunters, however, show that the GFDL is less sensitive to these data than the GFS is.

3). When I attended the AMS hurricane conference in May 2006 in Monterey, I came across a poster presentation by Dr. Jim Goerss that evaluated the impact of QuikSCAT on the NOGAPS model. His study was far more comprehensive, and included 12 hurricanes, 5 typhoons, and 7 tropical storms from a 6-week period in 2004. The number of cases was 212 at 72 hours, eleven times as many as the study Proenza cites. Dr. Goerss found that QuikSCAT probably improved 24-hour track forecasts by 2.5% (90% confidence of this), but at all other forecast times (48, 72, 96, and 120 hours), QuikSCAT had no statistically significant effect (i.e., zero effect).

It is hard to compare the results from these two studies, since they used two different data assimilation systems. We do not know if they used all the data, or how they treated the vertical impact of the data. The uncertainties are high, and Proenza's simple statement that QuikSCAT data improves hurricane tracks forecasts by 10% and 16% is unreasonable, without at least making mention that these numbers are highly uncertain.

I believe that NHC official forecasts for landfalling storms in the Atlantic would not be significantly affected by the loss of the QuikSCAT satellite. I can't think of a hurricane scientist out there who would defend using a study with only 19 cases that didn't focus on landfalling storms, to make the case Proenza is making--particularly in light of the data from the unpublished Goerss study showing no effect of QuikSCAT data on NOGAPS model tropical cyclone track errors. Proenza should have at least attached some measure of uncertainty to his numbers, which he did not.

One could argue that the study cited by Proenza has undergone peer review, and is thus the only scientific study one can use to make arguments on QuikSCAT's effectiveness. The Goerss study has not been published in a journal, and has not undergone peer review. However, Proenza was making his QuikSCAT accuracy arguments in March, two months before the Zapotocny study he cited had been accepted for publication.

QuikSCAT misconceptions
The numbers pushed by Proenza have led to some potentially serious misconceptions about QuikSCAT. The Congressional Record has this to say about QuikSCAT:

"A single plane gathering data is like a tiny fishing line collecting data only along the single strand of the line. The satellite, on the other hand, provides rich, detailed data horizontally from one side of the storm to the other side, and vertically, from the ocean surface to the top of the storms swirling winds. The QuikSCAT is like a detailed MRI."

Well, QuikSCAT is not like an MRI, it just measures the ocean surface winds. In a letter written by Representatives Melancon and Klein in support of H.R. 2531, there are comments that data from the reconnaissance aircraft are inferior to the data from the QuikSCAT:

"Short-term options for replacing QuikSCAT include hurricane hunter aircraft, buoys, and foreign satellites--all of which will collectively produce inferior data."

There is not a hurricane forecaster anywhere that would trade hurricane hunter data for QuikSCAT. Lawmakers may start cutting aircraft reconnaissance with misconceptions like this. That would be a disaster.

I would hate to lose the QuikSCAT satellite, and have been calling for a replacement since before Mr. Proenza came on the job. QuickSCAT data is invaluable in identifying weak systems and in defining storm structure, particularly of outer wind radii of 34 knots and 50 knots. This is particularly true outside of the Atlantic, where there are no Hurricane Hunter flights, and in the Atlantic beyond where the Hurricane Hunters can reach. Track forecasts for tropical cyclones in the Pacific and Indian Oceans may benefit from QuikSCAT data, since Hurricane Hunter information is not available. QuikSCAT also helps identify when a tropical depression or tropical storm is intensifying.

Besides hurricanes, the QuickSCAT data is invaluable to the Ocean Prediction Center, which now issues hurricane force wind warnings for extratropical storms in the Atlantic and Pacific. Search and rescue missions, and the U.S. Navy also greatly benefit from QuikSCAT. QuikSCAT should be replaced, but not due to a rush knee-jerk reaction that will get us a replacement with old technology. NHC needs a "next-generation" scatterometer, one that has greatly improved capabilities to help tackle the structure and intensity problem. We should take our time, and deal with a gap in coverage, if it gets us an instrument that has higher resolution, higher saturation speed, and is not adversely affected by rain. Such a gap would not put the public at risk.

It greatly troubles me that the most visible and admired member of my profession has failed to use good science in his arguments for funding a replacement of the QuikSCAT satellite. The Director of the National Hurricane Center needs to be an able politician and good communicator, but being truthful with the science is a fundamental requirement of the job as well. Mr. Proenza has misrepresented the science on the QuikSCAT issue, and no longer has my support as director of the National Hurricane Center.

Other critical concerns--lost in the hubbub?
We strongly support many of the valid concerns Proenza has raised. Of particular concern are the slashing of critical research funding for the Joint Hurricane Testbed (JHT) from $1.7 million to $1 million, and the lack of adequate yearly increases to the National Hurricane Center budget. Both of these important concerns still remain to be addressed; they were quickly overshadowed by a frantic campaign by lawmakers to fund a new QuikSCAT satellite. The JHT provides the means for promising research to be tested in the NHC operational environment, usually resulting in a successful transition to an operational product at NHC. This program has been extremely successful, and its budget should have been increased, not slashed. As hurricane activity has increased dramatically over the last twelve years, NHC's budget should have increased accordingly, but it did not.

Proenza also raised legitimate concerns about NOAA's effort to promote their "Corporate Identity" by renaming the National Hurricane Center and National Weather Service. The new organizations would be called the "NOAA Hurricane Center" and the "NOAA Weather Service". He also justly complained about NOAA's plan to spend between $1.5 million and $4 million on a "bogus" 200-year NOAA anniversary celebration.

While wanting to take a neutral stand as to whether to call for Proenza's dismissal, Senior NHC Hurricane Specialist Lixion Avila clearly shares the concerns that have been put forth by the other senior forecasters Richard Pasch, James Franklin, and Richard Knabb, and former director Max Mayfield. Avila noted, "If I [was] the director of the hurricane center, I would not spend my time fighting for QuikSCAT--I would be fighting to make sure that the reconnaissance planes are always there." That leaves a vacationing Jack Beven as the only senior hurricane forecaster to not comment publicly on the issue. Max Mayfield has refrained from making public comments on the deteriorating situation these past months, but all of his comments in the Miami Herald article lend support for the hurricane forecast staff. Given his previous experience in the position of NHC Director and his successful tenure, his feedback counts tremendously.

With the busiest part of hurricane season just a few weeks away, expect a decision on Bill Proenza's tenure to be made soon.

Jeff Masters and Margie Kieper

Having lost the support of most of his senior forecasters, and having misrepresented the science on the importance of the QuikSCAT satellite on hurricane forecasts, it would be best for Mr. Proenza to step down as director of the National Hurricane Center.

--Jeff Masters

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1414. WeatherfanPR
8:09 PM GMT on July 05, 2007
TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT THU JUL 05 2007

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN
SECTIONS OF SOUTH AMERICA...AND THE ATLANTIC OCEAN TO THE
AFRICAN COAST FROM THE EQUATOR TO 32N. THE FOLLOWING INFORMATION
IS BASED ON SATELLITE IMAGERY...METEOROLOGICAL ANALYSIS...
WEATHER OBSERVATIONS...AND RADAR.

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...TROPICAL WAVES...

TROPICAL WAVE IS ADDED TO 12Z ANALYSIS HIGHLY TITLED ALONG 4N28W
11N26W 16N21W ESTIMATED TO BE MOVG W 10-15 KT. THE DAKAR UPPER
AIR TIME SECTION SHOWED A DISTINCT WAVE PASSAGE LATE JUNE
2ND/EARLY JUNE 3. THIS BROAD WAVE CONTAINS AN AREA OF LOW-LEVEL
TURNING IN THE VICINITY OF 10N27W WELL DEPICTED BY A PAIR OF
SURROUNDING SHIP OBS. IN ADDITION...THESE OBS ALSO INDICATE THAT
THERE IS SLIGHTLY LOWER PRES NEAR THE ANALYZED AXIS AS COMPARED
WITH SFC OBS TO IT'S E AND ALONG THE W AFRICAN COAST. A LARGER
SCALE INVERTED V-TYPE STRUCTURE IS APPARENT FURTHER TO THE
NE...WHICH WAS THE REASON FOR SLOPING THE WAVE IN THAT
DIRECTION. MINIMAL SHOWER ACTIVITY IS ASSOCIATED WITH THIS
FEATURE.

A 1014 MB LOW PRES SYSTEM CENTERED NEAR 11N49W IS MOVING W 10-15
KT. THIS WEAK LOW CONTINUES TO HAVE MINIMAL TSTM ACTIVITY
CONFINED TO THE SRN SEMICIRCLE. VIS IMAGERY TODAY HAS SHOWN THAT
THE CIRCULATION APPEARS OPEN AT TIMES...SO TO BETTER FIT THE
OVERALL STRUCTURE A TROPICAL WAVE WILL BE ADDED ALONG THE LOW AT
18Z.

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1410. underthunder
2:06 PM CST on July 05, 2007
what is the current location of 96l please..
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1409. StormHype
7:52 PM GMT on July 05, 2007
Can't find money for QuikSCAT or NHC budget increases but we are still building schools and police stations in Iraq. What's wrong with this picture?
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1407. Boatofacar
7:59 PM GMT on July 05, 2007
All this talk about weather, ..er food, has made me hungry! Im off to Publix for a BoarsHead Sub. Any vegetarians out there please forgive me
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1403. WPBHurricane05
3:52 PM EDT on July 05, 2007
LOL!!! Boatofacar!!!

Oh wait was that a joke???
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1399. MisterPerfect
7:45 PM GMT on July 05, 2007
can you handle Tomato Soup that is 89 degrees on the surface, moving 25 knots?
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1396. MisterPerfect
7:42 PM GMT on July 05, 2007
Gentlemen, enough of this bickering, this is a Tomato Soup blog remember?>
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1395. Jedkins
7:38 PM GMT on July 05, 2007
Posted By: ricderr at 7:35 PM GMT on July 05, 2007.

jed....who said i was talking about you?....LMAO......




Well you used a quote from one of my posts so, it sure seemed that way lol



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1393. ricderr
7:37 PM GMT on July 05, 2007
what?...you jp????....good..and you can verify then..that i never....cough...never...cough...picked on you.....LMAO
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1391. SCwxwatch
7:34 PM GMT on July 05, 2007
Jed your repeating yourself.

Got your point the first go round ;)
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1390. ricderr
7:34 PM GMT on July 05, 2007
jed....who said i was talking about you?....LMAO......
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1389. Jedkins
7:20 PM GMT on July 05, 2007
Posted By: ricderr at 7:19 PM GMT on July 05, 2007.

its a weather blog lets be real here.



reality.....in this blog...aint gonna happen........heck.....75 percent of all bloggers...claim to know better than their local mets




For one, Ive never said I'm better then the local mets are, read my posts more carefully. And please don't put me in the same bag as everyone who says they better then the local mets. I don't need to explain or prove that I'm better then the real mets anyway.


Actions speak louder then words. Now of course you could say, wheres my proof? And of course, either by a lie or just assuming I'm not accurate.

But a lot of people like outrocket and bob that have been on here along with me way before any of you can back up that I have caught many errors of the real mets. Now of course I'm not always right. But nobody is.


Oh and there are great forecasters Like Denis Philips who are real straight foward forecasters. That do real forecasting. Not puppet forecasting.


Hes one of the most accurate forecasters Ive seen. Way better then me.






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1388. weathermanwannabe
3:30 PM EDT on July 05, 2007
A strong Florida boomer is actually a sight to behold if you are not used to it; ran into a group of Croatian tourists in Orlando a few weeks and they throught the world (Disney World that is) was coming to an end after a nice round of thunderstorms came through...They were actually pretty worried and shaken by the storm and I told them that this was typical in Florida...
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1387. BoyntonBeach
7:27 PM GMT on July 05, 2007
Man o Man, I just opened the garage door to see the rain & a percussion bomb of the loudest ever thunder boomer goes off, rattled right through me. Stood there in disbelief for a minute...almost in shock...Wow!
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1384. thisisfurious
7:22 PM GMT on July 05, 2007
Sorry all for the bickering. I will try and be a big girl as well and take it straight to email.

All though that mention of tomato soup does sound might enticing. Especially one with a chance of development.

forgiven?
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1383. WPBHurricane05
3:22 PM EDT on July 05, 2007
If you two cant stop bickering then there is only one place that you gan go..

The Debate Blog
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1382. nash28
7:20 PM GMT on July 05, 2007
One thing is for sure.....

Can't wait for the next Dr. Masters blog. Getting tired of seeing Proenza's mug each time I hit the blog.
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1379. ricderr
7:21 PM GMT on July 05, 2007
MP..it will develop
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1376. ricderr
7:18 PM GMT on July 05, 2007
its a weather blog lets be real here.



reality.....in this blog...aint gonna happen........heck.....75 percent of all bloggers...claim to know better than their local mets
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1375. thisisfurious
7:11 PM GMT on July 05, 2007
a waterspout this morning and now a funnel cloud in kendall! what a day!
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1373. ricderr
7:11 PM GMT on July 05, 2007
oh no furious......no walls...i'm a transplant.....i just enjoy different fruits from different places.....
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1372. weathermanwannabe
3:09 PM EDT on July 05, 2007
Can't tell if the precip is actually making it to the ground but it looks (on sat) that Lake O is going to get a little bit of rain today...
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1371. thisisfurious
7:07 PM GMT on July 05, 2007
Ric,

That is quite possible. Perhaps we should build walls around each state, instead of just the southern end of the country.

Or just slower acclimation time is necessary.

And just because one is bad, doesn't mean you throw out the whole bushel.


But that Utah... what a pretty country.

:o)
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1370. MisterPerfect
7:08 PM GMT on July 05, 2007
Funnel cloud sighted; high winds forecast
By TIM CHAPMAN
tchapman@MiamiHeraldcom
A line of violent thunderstorms marched a funnel cloud Thursday afternoon afternoon at Coral Way and 87th Avenue.

The National Weather Service warned of high winds in the Kendall area and low visibility.

The funnel cloud was reported around 2 p.m. by Miami-Dade Fire Rescue.

There was no evidence that the funnel cloud touched down.

Still, for many South Florida residents it was another day of intermittent downpours.

The weather service said winds of up to 50 miles per hour were expected in the vicinity of the Palmetto Expressway in Kendall.
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1369. WPBHurricane05
3:08 PM EDT on July 05, 2007
Oh boy here comes a debate.

The Debate Blog
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1367. WPBHurricane05
3:07 PM EDT on July 05, 2007
n another question who thinks theres a possibility that 96L could deveope still?

I highly doubt it.
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1366. RL3AO
2:06 PM CDT on July 05, 2007
Sounds exciting on here.
1365. ricderr
7:03 PM GMT on July 05, 2007
Humble as apple pie. Just not quite as sweet.

i only like sweet apples myself...there's this farm i know in utah....grows the best apples....bugs pierce them though.....and they for some reason...don't transport well.....brought some to florida..and i think they couldn't take the humidity...
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1364. thisisfurious
7:01 PM GMT on July 05, 2007
What do you mean, who is furious?

I don't really know what most people's moods are on the blog, but I am feeling quite fantastic, considering.

Or are you asking who I am?

If so - just another WU blogger and NHC supporter who came here to learn with the rest of amateur weather geeks.

Humble as apple pie. Just not quite as sweet.
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Dr. Masters co-founded wunderground in 1995. He flew with the NOAA Hurricane Hunters from 1986-1990. Co-blogging with him: Bob Henson, @bhensonweather

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