Challenging Bill Proenza's QuikSCAT numbers

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

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 He cited an unpublished study, "A Two Season Impact Study of Four Satellite Data Types and Rawinsonde Data in the NCEP Global Data Assimilation System", by Tom H. Zapotocny, James A.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

Reader Comments

Comments will take a few seconds to appear.

Post Your Comments

Please sign in to post comments.

Sign In or Register Sign In or Register

Not only will you be able to leave comments on this blog, but you'll also have the ability to upload and share your photos in our Wunder Photos section.

Display: 0, 50, 100, 200 Sort: Newest First - Order Posted

Viewing: 1514 - 1464

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44Blog Index

1514. weatherboykris
11:05 PM GMT on July 05, 2007
You can make a "hurricane proof" house,but it would be very expensive.You'd want poured(not block) concrete walls,the right kind of roof,shutters,etc.
Member Since: Posts: Comments:
1513. WPBHurricane05
7:05 PM EDT on July 05, 2007
weatherboykris- He lives on an island in Tampa Bay. After looking at the evacuation map it appears that he would have to leave for even a Cat 1.
Member Since: Posts: Comments:
1512. FLfishyweather
11:01 PM GMT on July 05, 2007
Nash, I saw at least 50 reports after Katrina that said the water was the deadliest thing in the storm.

Now I know New Orleans was surrounded by lakes, but Tampa Bay aint exactly your highest elevation either.
Member Since: Posts: Comments:
1511. nash28
11:03 PM GMT on July 05, 2007
Michael, I live in Apollo Beach. Look it up. If a CAT2 cane is gonna be anywhere close to splitting the uprights of the Bay, myself, my wife, my beautiful dog and my documents are heading to Atlanta! Not worth it.
Member Since: Posts: Comments:
1510. Miamiweather
11:04 PM GMT on July 05, 2007
hey nash you got mail
Member Since: Posts: Comments:
1507. RL3AO
6:03 PM CDT on July 05, 2007
You just have to be prepared.
1506. weatherboykris
11:00 PM GMT on July 05, 2007
Posted By: WPBHurricane05 at 11:00 PM GMT on July 05, 2007.

randommichael- After going through Hurricane Frances, Jeanne, and Wilma, I would recommend evacuating for a cat 5!!!!

Actually,unless you're in a surge zone or a mobile home,you should stay home for most hurricanes,even a slow moving 5,provided you've got shutters and your house is well built.Even if you're only 10 miles inland,those Cat 5 winds won't make it that far inland.In Andrew,the NHC says the only land area that had Cat 5 winds was the immediate beach.10-20 miles inland,the winds in a slow moving 165mph storm will likely max at 125-135,assuming you go through the north eyewall.
Member Since: Posts: Comments:
1505. nash28
11:01 PM GMT on July 05, 2007
It would be horrific beyond comprehension in Tampa Bay. You thought New Orleans was bad???

This would be like an Atomic Bomb went off. St. Petersburg would be wiped off the map! Why? Most of the infrastructure is VERY old and built WAY BEFORE post-Andrew code.
Member Since: Posts: Comments:
1503. nolesjeff
10:59 PM GMT on July 05, 2007
Michael, I live in southwest florida and we were overdue the 20 years i had lived here, Then came Charlie. believe me, It only takes one. I live on the water also, we had maybe a 4 ft storm surge and water was over my seawall. I am 8.5 ft above sea level. You need to be prepared to leave!!!
Member Since: Posts: Comments:
1502. WPBHurricane05
7:01 PM EDT on July 05, 2007
weatherboykris- That looks like a stronger pulse than predicted. Things are about to get active.
Member Since: Posts: Comments:
1501. RL3AO
6:01 PM CDT on July 05, 2007
The surge from a Cat 3 is at least 10 feet. You said you were 3 feet above the water. That means you would be under 7 feet of water.
1500. WPBHurricane05
7:00 PM EDT on July 05, 2007
Michael- Here is the evacuation zones Link

Looking at that it appears that you would be evacuated for a Cat 1 cane.
Member Since: Posts: Comments:
1498. nash28
10:58 PM GMT on July 05, 2007
Of course they did. That's how they make money! No one is hurricane proof from a CAT5. I don't care where you live.

If it isn't the water that kills you, in a CAT5 the wind will slice you to shreds with glass, garbage cans, tree limbs, etc...

No house is worth staying for.
Member Since: Posts: Comments:
1496. weatherboykris
10:59 PM GMT on July 05, 2007
Member Since: Posts: Comments:
1495. WPBHurricane05
6:58 PM EDT on July 05, 2007
randommichael- After going through Hurricane Frances, Jeanne, and Wilma, I would recommend evacuating for a cat 5!!!!
Member Since: Posts: Comments:
1494. RL3AO
5:58 PM CDT on July 05, 2007
The winds won't be the problem. It will be surge. So unless you have a waterproof house, it sounds like you would not survive a Cat 5. You would drown.
1493. Alec
6:58 PM EDT on July 05, 2007
yeah Nash, I knew you meant "strength"....I stir up occassionally too!LOL
Member Since: Posts: Comments:
1491. nash28
10:56 PM GMT on July 05, 2007
Sorry Alec, you were right. Meant to say strength..:-) That saved our asses on several storms that trashed the panhandle.
Member Since: Posts: Comments:
1490. WPBHurricane05
6:54 PM EDT on July 05, 2007
I remember visiting Tampa and more specifically Ybor City and the Channelside district last year. That area appears very flood prone and like Nash said if a hurricane hits north of the bay, that would be bad news since the winds will be pulling water from the bay into Tampa.

Also, Family Disaster Plan.
Member Since: Posts: Comments:
1489. nash28
10:53 PM GMT on July 05, 2007
Davis Island would be creamed. You would have storm surge to the tune of 30ft and above with the CAT5 scenario...

Bottom line... CAT3 or more... Get OUT of its way!
Member Since: Posts: Comments:
1488. RL3AO
5:55 PM CDT on July 05, 2007
Surge from a Cat 3 cane is 10+ feet. You would be put under a mandatory evac.
1486. Alec
6:51 PM EDT on July 05, 2007
Nash, with Dennis, and those other Panhandle storms it was actually the strength of the ridge(covering the FL peninsula) that kept these storms from turning right into W Coast of FL......weaknesses in the ridge would allow Atlantic storms to curve out to sea in general...
Member Since: Posts: Comments:
1485. nash28
10:50 PM GMT on July 05, 2007
But, to really answer your question as far as what would it be like for a CAT5, or any major hurricane to come right up the gut through the Bay..... Utter devastation.... Worse than New Orleans. It would basically make St. Petersburg an island seperated from Tampa Bay. We're also talking about a massive loss of life in St. Petersburg since it is mostly retired and handicapped elderly people...

I can only hope that Mayor Rick Baker has the plan in place RIGHT NOW to bus those who cannot mobilize themselves, out of harms way.

That is my biggest fear.
Member Since: Posts: Comments:
1483. RL3AO
5:53 PM CDT on July 05, 2007
How far is your front door above the sea?
1482. CFLSW
10:46 PM GMT on July 05, 2007
Last direct hit on tampa bay was 1932 or 33 and on Dec. 3rd or 2nd cant keep them straight.
it was a cat2 and is said to killed at least 125 people
Member Since: Posts: Comments:
1481. WPBHurricane05
6:52 PM EDT on July 05, 2007
You live on an island michael?? If so I would also recommend you have an evacuation plan.
Member Since: Posts: Comments:
1480. WPBHurricane05
6:49 PM EDT on July 05, 2007
RL3AO, I guess what I am asking is last year I saw a map with percentages on it showing the likelihood of a direct hit that year. Is anything like that out yet? If we are going to be hit this year, I'd like to go ahead and get prepared.

I don't like looking at landfall predictions months into the future, and especially from but here it is anyway.
Link 1
Link 2
Member Since: Posts: Comments:
1479. FLfishyweather
10:49 PM GMT on July 05, 2007
Anyone in south florida see the lightning yesterday? Guess the weather was in the 4th of July spirit.
Member Since: Posts: Comments:
1477. nash28
10:47 PM GMT on July 05, 2007
Random- We are ALWAYS at a high risk of a direct hit. And yes, as each year passes without one, we are lucky. There have been SEVERAL close calls in recent years... Charley in 2004 is obviously the most recent... But even storms that were dead set on Tampa Bay with the models for DAYS on end, that shifted ever so slightly (thank you weakness in the ridge) that unfortunately ended up drilling the panhandle.
Member Since: Posts: Comments:
1475. cajunkid
5:49 PM CDT on July 05, 2007
there is some spin off the coast Link
Member Since: Posts: Comments:
1473. WPBHurricane05
6:44 PM EDT on July 05, 2007
We still need to perfect our 5 day forecast before we perfect our 5 month forecast. That is why I put very little thought into the pre-season forecast. Always be prepared!! And always have a hurricane plan. Also, remember that hurricanes don't know or care how much an area has been hit or how infrequent a storm hits there. Give them the right conditions and they will form.
Member Since: Posts: Comments:
1471. nash28
10:37 PM GMT on July 05, 2007
Hey Randommichael- I live on the south shore of Tampa Bay. Good to see you on the blogs!

Ok, to answer your question is very difficult. Is Tampa Bay "overdue" for a direct strike from a major hurricane? Statistically yes. The last major hurricane to hit this area was back in 1921, when a CAT3 made landfall in Tarpon Springs. So, we are talking about 86 years since a major hurricane struck Tampa Bay. Having said that, I hate to use that term "overdue" because no one in my mind is "due" for loss of infrastructure and life. However, this is the real world we live in and New Orleans got damn near relocated on topography maps from Katrina after going a pretty long time dodging the bullet.

Now, we are somewhat lucky in terms of topography and climatology. The way that Tampa/St. Pete juts out from the peninsula and the way steering currents are "typically" make it very hard for a direct landfall right up the mouth of the Bay. The worst case scenario would be a direct hit during high tide just a tad south of the Big Bend area.
Member Since: Posts: Comments:
1470. RL3AO
5:45 PM CDT on July 05, 2007
If a major cane hit Tampa, then you would probably be underwater.
1469. FLfishyweather
10:43 PM GMT on July 05, 2007
hey everyone

just wanted to see whats up
Member Since: Posts: Comments:
1468. RL3AO
5:43 PM CDT on July 05, 2007
What you are asking michael is like asking if your town will be hit by a tornado within 5 years then asking which day and how strong it will be.
1464. RL3AO
5:38 PM CDT on July 05, 2007
No one knows michael.

Viewing: 1514 - 1464

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44Blog Index

Top of Page

Dr. Jeff Masters' WunderBlog


Dr. Masters co-founded wunderground in 1995. He flew with the NOAA Hurricane Hunters from 1986-1990. Co-blogging with him: Bob Henson, @bhensonweather

Local Weather

45 °F

JeffMasters's Recent Photos

Cedars Plastered by Snow
Snowstorm over Dunham Lake
Beech tree fall color in the U.P.
Altocumulus clouds over Pictured Rocks National Lakeshore beaver pond