It's no secret that Safeco Field is a pitcher's park. While its dimensions aren't that impressive, it lies at sea level and boasts a fairly mild temperature, both of which deaden the air. Previous studies have shown that Safeco will reduce runs by 5% and home runs by roughly the same amount, which leads to the conclusion that power will find itself at a disadvantage in Seattle.
This is not entirely true.
The prevailing wind in Seattle is a northwesterly off Puget Sound. In terms of the ballpark, this means that the wind comes in from left field and blows towards the right field foul pole. We all know it's easier to hit with the wind than into it, and so we understand that right handed hitters are going to have more problems hitting home runs than left handers*. The key, of course is to know by how much. Does Safeco actually inflate left handed power? If so, left handed power bats are far more valuable than a right handed bat with the same power - they perform in the same lower run environment but simultaneously have their own output boosted compared to average.
Tackling this problem is a fairly tricky process. I could have looked at home run distribution in Safeco Field vs. league average over the past several years and made an attempt to correct for bias in the Mariners roster, but fortunately I didn't have to. The work has already been done (albeit in a completely different way) by HitTracker's Greg Rybarczyk (here). I have taken his work and modified it slightly in order to give a graphical output of Safeco's equivalent fence distance below**:
Figure 1: Equivalent Fence Distance for Safeco Field.
I scaled the difference between Safeco and league average by two so it's easier to see, but I think that the graphic is fairly instructive. Left-handed bats get a significant advantage to playing in Safeco, while righties get killed. I wouldn't take the above as 100% accurate (it's a smoothed line between five datum points), but it's close enough to give us the overall picture. Left field is a pain to hit to, LCF is really hard to hit the ball out of, and centre field is a canyon of death (the equivalent distance to centre is over 420 feet). Richie Sexson's time with us just got a lot more impressive.
*At this point I should note that Safeco Field's dimensions decrease home runs between the left field foul pole and right-centre field and increase them to RCF and right field proper without the effect of wind.
**Assuming that distance and energy input into a baseball are quadratically related (which isn't true, but it's close enough) and by using wind speeds that force Safeco to match the standard HR/FB factor, we can map out the fence distances that are equivalent to the increase/decrease in difficulty of hitting a home run in that area of the park.
10 recs | 130 comments
Why in the world
did they decide to make the dimensions so gigantic in the first place? It immediately hurt the RHB’s we had on the team in 1999, and they never thought to make it a bit more offense freindly?
bagsflyfree - January 11, 2010
It's not just the dimensions
I don’t think anyone was really thinking about just how much the wind would impact the park – for left field it’s at least as important as the actual dimensions
Graham MacAree - January 11, 2010
I've never been to safeco
So i think clearly on the as i see it on TV plane.
bagsflyfree - January 11, 2010
Oh boy
You are missing out. It is absolutely lovely. There isn’t a bad seat in the house.
melenious - January 11, 2010
i know i am
it’s a money/time/travel thing.
bagsflyfree - January 11, 2010
Please capitalise properly in the comments
Thanks!
Graham MacAree - January 11, 2010
I hope one day you do
You will be mesmerized. Welcome to LL, by the way!
melenious - January 11, 2010
Sorry and thank you.
bagsflyfree - January 11, 2010
upper deck over right field is pretty bad
Corco - January 11, 2010
When you end up behind a bunch Red Sox fans, that seat sucks.
InSpokane - January 12, 2010
When you end up anywhere near a bunch of Red Sox fans
Life sucks
wandergeist - January 12, 2010
I have heard
That when they were considering the orientation of the playfield, they looked at wind data… but they looked at annualized wind data, not just April-Sept, and the annual data is dominated by the stronger southerly winter winds that would tend to carry balls out… if anyone was hitting them there in January. D’oh.
Of course the architects/engineers had to look at the annual data for the building as a whole when considering sail loads etc, but that is independent of the playfield orientation — obviously the stands would all be different if home base was in a different corner, but the overall footprint of the building/roof and the way the roof retracts across the BNR tracks is determined by the site. And the orientation they picked suppresses flies to LF more than they intended.
In fact, I’m pretty sure I recall an interview with Lincoln (or Armstrong?) where he admitted that the data they used to orient the field was annual data, and they didn’t realize they were going to get so much out of the NW in the summer months.
wandergeist - January 11, 2010
That's interesting about the wind miscalculation, hadn't heard that before
Wish I had kept the seating map the M’s sent out for prospective ticket buyers before the ’99 season. The original plans for the the outfield looked kind of like old-old Yankee Stadium or the L.A. Coliseum before Dodgers Stadium was built. They wanted the un-Kingdome.
lemonverbena - January 12, 2010
L.A. Coliseum if LF and RF were flipped, I should say
after seeing the image below. Basically, a way more ginormous outfield. I need to find that old layout.
lemonverbena - January 12, 2010
My guess would be that they wanted to distinguish the dimensions from those of the Kingdome
Poochie - January 11, 2010
Griffey
seattlebruin - January 11, 2010
Our park is fair!
melenious - January 11, 2010
Thank you Chuck Armstrong.
msb - January 11, 2010
Oh, boy is Adrian gonna have some fun in Boston
vivaelpujols - January 11, 2010
Safeco Field LF HR factor: 83
Fenway: 105 (no wind since I have no idea).
Not to mention doubles. Beltre might get 80 XBH in 2010
Graham MacAree - January 11, 2010
Interesting, I always assumed the monster turned homeruns into doubles and fly outs into doubles...
Given the huge 2B factor and the low HR factor of Fenway. I guess the low HR factor is the ridiculous center field?
lailaihei - January 11, 2010
The HR factor for CF (no wind) there is 57.
!
Graham MacAree - January 11, 2010
Holy fuck.
I mean the short porch in RF is a happy place for lefties, and apparently popping it over the monster isn’t a big deal, so they had to make up for it somewhere.
lailaihei - January 11, 2010
Minute Maid's CF factor is ridiculous at 37, but somehow Comerica beats it out at 35.
And I never realized before how much baseball favored lefties… They already get a 2-step advantage and momentum going toward first out of the box, and on top of that, MLB average park factors favor lefties; it’s not just Safeco.
lailaihei - January 11, 2010
I think only five hitters have hit HR to centre in Detriot. I have no proof of this I just remember hearing it on a broadcast.
That said Minute Maid has never seen one hit out to dead centre. Out of all hitters in the NL I can see Reynolds probably having the best chance of doing this going by his hit profile.
EnglishMariner - January 12, 2010
Going by HitTracker
there seems to be an average of five per year. No way to tell who is hitting them though, could be all Granderson and Cabrera for all I know.
Bearskin Rugburn - January 12, 2010
Delmon Young and Michael Cuddyer hit back to back HR to centre during Washburn's Tigers debut!
Graham MacAree - January 12, 2010
By God you're right!
Other notable slugger going deep to dead center field: Miguel Olivo, Clete Thomas. Stunning.
Bearskin Rugburn - January 12, 2010
sluggers
Bearskin Rugburn - January 12, 2010
That's ok
When Miguel Olivo is the only other guy in the list, you don’t need to make “slugger” plural.
wandergeist - January 12, 2010
MInute Maid had a homer to dead center in 2006
Hilariously, it was Jacque Jones off Roger Clemens. There’s video (it’s Aug 15). HitTracker is an amazing site.
Bearskin Rugburn - January 12, 2010
Sexson hit it off the flag pole in Minute Maid.
But it counted as a double.
Mariner John - January 12, 2010
That should be like
A double home run. Run around the bases twice and rack up another run.
wandergeist - January 12, 2010
Thanks for this.
I’ve been thinking about this a lot lately.
JonBBT - January 11, 2010
Observations by a paraglider pilot sitting at 1st base
As with all weather observations, I don’t think things are quite that simple. Although NW winds are prevalent during the days of sunshine, at most other times the prevailing winds are SW. If you watch the smoke from Kidd Valley (under the Landing near the LF foul pole), sometimes it wraps around the entire stadium in a clockwise fashion. That happens when the SW wind gets captured and directed by the LF, CF stands and scoreboard. It’s often quite chilly at 1B from the wind blowing in from LF.
Also, the Home and RF stands create a rotor effect from the SW flow that pushes down into the still air within the stadium, knocking things down most flyballs.
Of course, all bets off when the roof is closed.
floydr - January 11, 2010
It's not that simple, but the system I had to work with required simple inputs, so all of the complexities got ignored.
Science!
Graham MacAree - January 11, 2010
This really underlines Bavasi's stupidity
I mean, this information should be pretty obvious to people paid to make personnel decisions in the ballpark. And the guy signs two right-handed power bats as his premiere decisions for the ballclub. We knew it was stupid at the time, but this illustrates just how stupid.
Also, wasn’t the park built this way in part to lure Griffey to stay? I think I remember discussion of a shorter left field porch because he was The Franchise at the time.
EireDuck - January 11, 2010
Yeah the Beltre signing was pretty stupid.
Mariner John - January 11, 2010
The reasoning for it was.
Bavasi signed him to hit 50 HR’s. It’s not the result he’s calling stupid but the process towards it.
Hopefulmsfan - January 11, 2010
Not even Bavasi was dumb enough to think 2004 was repeatable.
There was a good deal of assumed regression built into the contract.
Teej - January 11, 2010
Exactly.
He came right out and said publicly several times that he didn’t expect Beltre to hit 40+ HRs. He expected solid offense with gold-glove defense.
It’s why even at the time I thought it would be Bavasi’s best signing ever. Anyone who doesn’t see that needs to have their eyes examined.
PositivePaul - January 12, 2010
What I remember from the signing
What I remember from the signing was Bavasi being interviewed and saying he thought Beltre had turned a corner in his career and expected pretty close to in between Beltre’s career offensive numbers and his breakout year. So Bavasi was that stupid. I also remember Beltre looking pudgy when they introduced him. He also came into camp that year kind of out of shape too as he commented on the next season when he said he had kind of let himself go the previous off season due to the tremendous confidence the 2004 season gave him. He learned his lesson though. But it always strikes me as odd that it seems like all players, even the ones with good work ethics, have to have that one off season where they let themselves go before they realize it will make for a crappy season the next season. Made me glad to see Gutie looked like he was in great shape the other day when they officially announced the signing.
hiskeyd - January 12, 2010
I don't think he ever came out and said that.
While he may not have signed Beltre for his glove completely, you can’t say Bavasi signed Beltre expecting 5 years like 2004.
Mariner John - January 11, 2010
I remember that about Griffey too
that the park was partially built with his hitting in mind. Then I heard that a reason for him to leave was that Safeco was a ’pitcher’s park.’
Snuffleupagus - January 11, 2010
We need more observations, more smoke, and the cloud!
I was really scared at a game last year when the Navy Seals (IIRC – it was Seafair I believe) parachuted into the stadium. One guy almost landed in the RF stands. It was pretty obvious to me that there was different air above the stadium than in the stadium.
floydr - January 11, 2010
The reply button next to the date stamp helps to keep conversations flowing
It’s much easier to follow a threaded discussion than a bunch of different sub-threads. But more observations wouldn’t really help, since when using Greg’s spreadsheet I have to pick one direction and one speed.
Graham MacAree - January 11, 2010
So sorry, another blog I post on automatically puts it below.
Red face.
floydr - January 11, 2010
Not a problem, just letting you know how the site displays comments
Graham MacAree - January 11, 2010
Wow! I never realized...
That our home 9 plays in a rectangle. no wonder Jose always pulls it right down the line.
Nichos - January 11, 2010
Wind Rose - for Duwamish Valley May 1 - Sep 30, 2009
Would have been better to have at least five years of data, (small sample size variability and all of that) but this was easy to get from the Puget Sound Clean Air Agency web site.
But it’s extremely important to remember that air movement inside the entire stadium is dominated by the stadium geometry. All parts of the stadium are subject to downwash and wake turbulence. That’s why the stadium characteristics change when the roof is closed – the building geometry changes, and the roof also suppresses much of the movement of air through the stadium.
++++
Now that is an unusually steady and narrowly focused wind from the NW – you seldom see that much dominance in a single flow sector. Since the geometry is fixed, the downwash and wake effects will be pretty stable.
Just speculating here – I think there’s a general low elevation air current that comes in past the left field foul pole – I’ve frozen my but off several times in the third deck seats near the Landing. That current just follows the stadium geometry – it heads toward home plate then turns and blows out to right field.
In addition, since the stadium is warmer than the surrounding area on summer nights, air in the stadium is going to tend to rise. So that air stream coming in at Lookout Landing rises as it reaches right field – some of it’s going to go escape the stadium in front of the right field 3rd deck seats, while the remainder is going to turn back toward center field and exit through the low open area on the east side of the stadium.
That circulation pattern knocks down balls pulled down left field line and generally boosts flies hit to right.
+++++
But the rest of the stadium air is also being heated and is generally rising up and out of the stadium. That air needs to be replaced somehow. I suspect that creates a more general air flow over the left field bleachers and onto the playing field. Notably that will be cold sinking air. So not only is that air coming in toward home plate, pushing fly balls back, it also has a downward vector, so it’s also knocking the balls down. As often observed fly balls to left field die. That get out of the infield fine, but as they reach the outfield they hang and then start dropping like a wounded quail.
++++
During a day game, especially on a warm day, the temperature effects will be much less. My intuitive observation is that on warm summer days there aren’t the differences in carry of fly balls that seems to prevail at night.
Steve Nelson - January 11, 2010
Thanks for this, Steve
Graham MacAree - January 11, 2010
Some added comments
I don’t think I explained some my thoughts on the left field air current as well as I could have.
You have a prevailing NW wind impacting the stadium, and there happens to be an opening in the face of the stadium at the NW corner, right at Lookout Landing. I think that creates that air current that I surmise exists.
As the current comes in it is higher than the playing field. So a low line drive down the line would not be influenced by the wind current. A high fly down the line will be greatly affected. Again, this comports with my observations. Since Jose Lopez hits a fair number of line drives, Safeco might actually be hurting him less than it hurts many right handed hitters.
Steve Nelson - January 11, 2010
The architects knew - wind loads were certainly factored into roof design
“But it’s extremely important to remember that air movement inside the entire stadium is dominated by the stadium geometry. All parts of the stadium are subject to downwash and wake turbulence. " I really like that statement; especially since it (probably) supports my assertion about SW and other winds knocking down balls, in addition to NW winds.
Another point I hadn’t put in until I read “structure” and “geometry” is that the architects and engineers designing Safeco Field certainly ran some sort of wind model against their design to figure wind loads, especially for the roof – it is after all a sort of sail. The data is probably available, but someone would have to pay the architects; sigh.
floydr - January 11, 2010
That's a totally different issue from how air flows inside the part ...
… without even considering that air flow inside the stadium changes when the roof is extended.
When they are looking at the sail forces, they are simply looking at how the air flows around and over the stadium with the roof extended; they aren’t going to be looking much at how the air flows inside the stadium.
In addition, inside the stadium the geometry is sufficiently complex that I doubt it could be modeled with any degree of reliability.
Steve Nelson - January 11, 2010
I think you'd be surprised at how little you have to know about wind loading in order to come up with a structural design
Graham MacAree - January 12, 2010
Very true
You can certainly get away with designing to maximum expected wind load, using the ASCE code for the wind zone, gust factors, etc.
Davey86 - January 12, 2010
I haven't had anything to do with structural since my college days but ...
… Since the roof isn’t structurally part of the stadium I would expect that it would receive it’s own analysis. I would further expect that analysis to consider possible behavior as an aileron as well as harmonics, both of which would involve modeling air flow.
Steve Nelson - January 12, 2010
You could probably just figure out max uplift based on a conservative quick analysis and design the whole thing for that
Graham MacAree - January 12, 2010
They probably spent a lot more money than this and came up with the exact same solution
seattlebruin - January 12, 2010
But the liability situation is different
If the roof has a problem and there is litigation alleging design defect, the standard for negligence is the level of care followed by people providing the same or similar services at the time the services were provided.
That’s a nebulous standard, and as a professional engineer or architect practicing in an area of high liability (and stadium construction is a high professional liability field) you always want to err toward “more rigorous” rather than “less rigorous”. Even if the answer is the same, you’ve covered your butt better if there’s a problem down.
And when the potential losses on a claim start at tens of millions of dollars, a little butt covering goes a long way.
Steve Nelson - January 12, 2010
You could, but the analysis is both mechanical and structural
It’s not just a question of what the uplift might be, but how it might affect the mechanical components as the roof is opening or closing. What happens if an 80-mph wind gust hits the roof as it’s being retracted or opened?
I also don’t know how sensitive the overall cost of the roof was in relation to the weight of the roof; i.e., how important was it to minimize the weight of the roof for the roof to properly open or close? What extra load-bearing capacity had to be added to the stadium walls to support the roof. (I suspect not much, but I don’t know.)
Those are factors that help might mitigate against simply making a simple and conservative assumption.
Steve Nelson - January 12, 2010
I think you're probably being remarkably generous to the folks who designed the roof
Graham MacAree - January 12, 2010
See my answer above on liability
The roof was an innovative design and had very high attendant liability. Unless they had some very good exculpatory language in the contract, no responsible engineering firm is going to undertake that design without leaving a good design and analysis trail behind them, one that can stand up in court under cross-exam and expert testimony professional liability trial.
I also recall that during the time Safeco was being built there was a lot of attention given to the mechanical aspects of the roof design.
Steve Nelson - January 12, 2010
No, he isn't
According to this article (PDF), they did extensive computer modelling including 1500 different load tests (for various positions of the roof with different wind and seismic loads). They also tested detailed scale models in a wind tunnel in Toronto (there’s a picture of the model in the tunnel on page 3 of this PDF article). Because of the way the roof sits over the building rather than on it, with wind going underneath, there’s a risk of aeroelastic uplift failure (which is a consideration with bridges but usually not with buildings) so they have a mechanism to “lock down” the moving parts of the roof when it is fully open or closed. And because it is sitting in a seismic zone (unlike the retractable roofs in most other cities like Milwaukee or Phoenix) they added dampers (that probably also help with wind) on the north side of the roof and those are monitored electronically in real time via 50 accelerometers.
They spent a lot of time and money looking at that roof.
The wind tunnel model doesn’t look large enough to give them really useful data about what the wind is doing inside the stadium when the roof is open (or closed), and I doubt their computer modelling told them much either since that wasn’t its intent. In any case, whatever NBJJ knows is proprietary data and I doubt they (or the team) feels like sharing (but damn, wouldn’t it be cool to have the model to run some dynamic flow studies on?).
Of course, you could try using THT’s calculator.
wandergeist - January 12, 2010
Nice find.
That’s consistent with my recollections. If I hadn’t been lazy I would have done a search at ASCE to see if I could find something about it.
Steve Nelson - January 12, 2010
I've heard the same thing before.
The wind flows down the left field bleachers, across the field and then exits up and out over the right field corner. The dimensions help left-handers, and they get a boost from the predominant airflow during night games. I have also heard it isn’t the same during day games, I believe because the air tends to be stiller in the afternoon, and the increased temperatures allow the ball to fly further.
Awesome job, Graham, and excellent explanation, Steve.
nathaniel dawson - January 11, 2010
As for someone that has never been to Safeco,
and won’t likely in the conceivable new future, this is an interesting insight into the field and the Mariners team construction philosophy, or lack of in the past. It is also a good illustration that HRs can occur if you can hit to RF and there are exaggerations by fans and media about the constraints of the field. Hooray for dingers!
aussie_chop - January 11, 2010
Almost from the time Safeco opened it's been known that Safeco is easier than average to hit HRs to right field
and the Giilivasi did correctly assert that Ibañez’s swing was ideal for Safeco. Many of us scoffed. Rumor has it that next years big LL/USM magazine is going to have a section devoted to our favorite recipes for preparing Ibañez crow (my fricasseing offering is outstanding).
Steve Nelson - January 11, 2010
Or in layman's terms, the park is more like a Yuni rectangle.
OlSalty - January 11, 2010
Bret Boone's 2001 seems even more impressive now.
I Lick Squirrels - January 11, 2010
I believe that Bret Boone had a lot of power to right field ...
… so he may have been less affected by Safeco than many other right-handed hitters.
Steve Nelson - January 11, 2010
Indeed
http://www.baseball-reference.com/players/split.cgi?n1=boonebr01&year=2001&t=b
Jeff Sullivan - January 11, 2010
BBall Ref is really neat
Robert - January 11, 2010
Damn, 12 dongs the other way, and 15 dongs to center.
That’s damn impressive.
Phil Hatzenbuehler - January 12, 2010
Jack seems to be the first GM to really build the team with Safeco in mind
rather than trying to put together a generic winning team. If this team comes together as Jack hopes it will, Safeco can be bigger advantage than most home fields for other teams.
Again, Jack is trying to take advantage of every angle to help this team win games.
Coug1990 - January 11, 2010
Hey, that diagram looks familiar
It’s almost like a virtual Polo Grounds!
wandergeist - January 11, 2010
That is a stupid fucking stadium
Gihyou - January 11, 2010
Yes it is.
Wow that is rediculous.
ARock - January 12, 2010
Jose Lopez and Kenji Johjima would combine for 200 home runs in that stadium.
Each.
CapSea - January 11, 2010
Wait, that's not possible.
CapSea - January 11, 2010
No, Jose Lopez and Kenji Johjima would combine for 200 home runs in this stadium.
Probably the worst venue for major league baseball ever, and yet it set the all time attendance record for an MLB game.
Vatinius - January 12, 2010
Novelty!
Phil Hatzenbuehler - January 12, 2010
What was the LF foul pole distance? 267 or something?
marc w - January 12, 2010
I think it might have been in the 240s but I'm not sure
pdb - January 12, 2010
251 according to the mighty intertubenet
pdb - January 12, 2010
Maybe the worst baseball field in the modern era, the left field fence was a joke.
It used to seat about 92,000 at the time. I went to the first Super Bowl Game there (it was called the NFL/AFL Championship game at the time) and the attendance was about 62,000. Tickets on the 40 yeard line cost me $16 each.
More to the point of the thread; the new Yankee Stadium produces 2.93 HRs per game and The Safe 1.93 per game, exactly one homer a game difference.
maqman - January 12, 2010
I'm finally not the oldest person here!
you’re my new best friend.
pdb - January 12, 2010
Careful!
HR/G at two different stadiums in a single season cannot be chalked up to park effects. Half the innings in each park were played by a specific offense (great in one case, poor in the other) and the other half by a specific set of pitchers. The stat you quote is misleading at best.
Bearskin Rugburn - January 12, 2010
I think the Yankees having the Yankees hitters
And the Mariners having the Mariners hitters also had a good deal to do with that ;-)
baetown415 - January 12, 2010
Where is that?
Fin - January 12, 2010
I believe that's LA Memorial Coliseum
Home of the Dodgers their first few years in LA, as well as the various pro football teams that have passed through LA (and now the USC Trojans). Amazingly an ASG, a WS, two Superbowls, and two Olympics took place there. And I somehow missed this at the time, but the Dodgers and Red Sox apparently played an exhibition there in 2008 to celebrate the Dodgers’ 50th year in LA.
wandergeist - January 12, 2010
That 2008 game is where this pic is from
pdb - January 12, 2010
Actually that picture is from the 1958 season.
This picture is from the 2008 expo game against the Red Sox:
Vatinius - January 13, 2010
*usc trojans
seattlebruin - January 13, 2010
This comment made me laugh... As did the immediate retraction.
seattlesundevil - January 12, 2010
I really can't express how cool I think this is
it’s really cool. Thanks, Graham.
Bearskin Rugburn - January 12, 2010
I agree with this comment.
Thanks for posting this! And hooray for Science!
AMb1valenT - January 12, 2010
An interesting aspect of this is that the design of Safeco ...
… might turn out to be the difference in Edgar making the Hall of Fame. Without being punished by Safeco his raw numbers, which are the only numbers many voters consider, would be significantly better.
Steve Nelson - January 12, 2010
Sheesh...
Even our ballpark has East Coast Bias! THAT’S good enough reason to modify the dimensions :-)
PositivePaul - January 12, 2010
This is way more wacky than the first image you posted.
CapSea - January 12, 2010
Yes I put up the wrong one at first
I was hoping nobody would notice.
Graham MacAree - January 12, 2010
I think I opened the thread at exactly the right moment
When I went to the page with the jump, there was one figure, without the exaggerated effect. Then I clicked on the jump, and exaggerated image came up. Then I backup to the front page, and got the original image. I went forth and back several times, noting the difference in images.
Later I noticed that my browser showed only the exaggerated image. so then I was sure of what had happened.
Steve Nelson - January 12, 2010
The first image was with no wind and no double scale, just so everyone who saw it knows
I was careless in my uploading!
Graham MacAree - January 12, 2010
F5 F5 F5 F5 F5 F5
CapSea - January 12, 2010
What affect does the roof open or closed have?
I remember when it first opened how there was talk about the ball would carry more with the roof closed.
TheEmrys - January 12, 2010
I don't think the roof is closed enough to have a significant impact over a season
and ultimately you would need something like a decade or two of data to get sufficient sample to be able to say how the park effects are altered. Unless you go to the park and start taking wind readings that is.
Bearskin Rugburn - January 12, 2010
Overall the effect of closing the roof should be to calm the wind currents inside the stadium.
It should greatly miimize, if not totally eliminate downwash inside the stadium associated with northwesterly winds crossing over the north side of the stadium.
Steve Nelson - January 12, 2010
I have seen both Dan Wilson and Rob Johnson hit home runs to CF with the roof closed.
That is all the data you need.
Sec 108 - January 12, 2010
Maybe they should close the roof for the half innings that the Ms hit
I don’t think that is a violation of MLB rules but I’m not that familiar with the rule book
Bearskin Rugburn - January 12, 2010
It violates the ground rules
That the team agreed to with MLB:
here
wandergeist - January 12, 2010
Wait, climactic?
killer_ewok18 - January 12, 2010 via mobile
I really wish Safeco had an array of anemometers
Distributed around the perimeter of the stadium (and maybe on the roof as well) in something like 1 meter intervals, with the data from those available on the internet. You could potentially get some really interesting information from that. Of course, if it’s available in real time it could get taken to a goofy extreme — Wak signals to the batter to step out of the box until an unfavorable gust passes…
wandergeist - January 12, 2010
You wouldn't want the anemometers on the perimeter and roof ...
… you would want them inside the stadium, suspended at varying heights from cables spanning across the stadium.
The data need isn’t to define the flow field impacting the stadium but how the air moves inside the stadium.
Steve Nelson - January 12, 2010
Yeah, I know
But that would kind of get in the way of gameplay, yes? (You think the “rings” at Tropicana are bad…)
So I settled on that as a compromise. Ideally you’d have a grid at field level too but I doubt they players would appreciate jumping over that either.
With an array around the perimeter you’d at least have an input for doing some CFD studies and checking the results. It’s true that wouldn’t capture everything — you wouldn’t know if air is escaping the stadium in a horizontal flow somewhere above the perimeter, or vertically in the form of (say) a thermal column, but it would at least be a start. And in fact the marine air around the stadium is usually stable enough that only a few days every season would thermal bubbles have much effect, especially in the very low altitude range of interest for fly balls. Pathetic adiabatic lapse rates make for weak thermals, no thunder storms, and very little lift for dingers, so flow over the structure is going to dominate. Unfortunately, given the structure, that flow is going to complex and turbulent.
wandergeist - January 12, 2010
You need to at least ten feet away from any solid surface (ground level, parapet, wall, etc) to get meaninngful data ..
… otherwise you’re just picking up surface turbulence.
Steve Nelson - January 12, 2010
Yeah, that's what all those flagpoles are for ;)
wandergeist - January 12, 2010
You could just constantly release tiny balloons with tracking hardware in them
That would give you endless amounts of info and get around your obstruction problem.
Edgar for Pres - January 12, 2010
Somebody get Cliff Mass on this.
msb - January 12, 2010
Or maybe beer-can helicopters
Like in “Twister”
I’m sure the players wouldn’t mind thousands of tiny balloons wafting about in the middle of a game. It couldn’t be any worse than an early April game in Cleveland, right?
wandergeist - January 12, 2010
Twister was my inspiration for this
I figured those metal sensors probably wouldnt work well though since we don’t have 100+ mph winds.
Edgar for Pres - January 13, 2010
Doesn't work
You would need the balloons to be neutral buoyancy and to have the center of gravity and centers of inertia all lie at the center of the ballon.
Steve Nelson - January 13, 2010
Don't they use smoke for a lot of wind tests?
Kermit. - January 13, 2010
Yes - but smoke particles are typically less than 1µ in diamater ...
… which means that their movement is governed by surface effects instead of inertial effects. That is to say, smoke particles go with the flow.
And even at that small diameter smoke particles will tend to not change direction as quickly as an air current. In doing particulate testing in boiler stacks it’s well known that if there is a bend or elbow in the stack a short distance upstream of the test location, the particulates will be concentrated in the stack along the wall that corresponds with the outside edge of the curve.
Steve Nelson - January 13, 2010
I can get a balloon to neutral buoyancy. Thats not hard. A little bit of He always helps.
To get over the center of gravity/inertia problem, you just need to get 6 balloons and mount the sensors in the middle.
Edgar for Pres - January 13, 2010
This post should be sidebarred somehow
the diagram alone is invaluable.
pdb - January 12, 2010
It's pretty amazing that the advantage in RF is greater than the disadvantage in LF
OlSalty - January 12, 2010
See?
Our park is fair!
wandergeist - January 12, 2010
Safeco Field: Fair and Balanced.
killer_ewok18 - January 13, 2010 via mobile
Tsk tsk
Bearskin Rugburn - January 13, 2010
Fair or balanced depends on team construction
It isn’t fair to RH power hitters but more than fair to the LH types, so RH DH or LFs have discounted value in The Safe. While a lot of fans keep moaning about their need for just that (RH DH or LF power batter) they would be better off with a RH high OBP type or one with a predilection for whacking RH pitchers.
maqman - January 13, 2010
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