In the new Yankee Stadium, it's not the wind…

Michael Salfino of SNY has a piece up reviewing a study done by Alan Nathan from the Department of Physics of the University of Illinois. The study was inspired by the idea that there is something of a wind tunnel in the new Yankee Stadium, which is affecting the number of Home Runs being hit there. He used Pitchfx data and batted ball data plus Greg Rybarczyk’s hittracker data to estimate the trajectory of fly balls and figure out how balls are carrying in all stadiums across Baseball, and to look at where the new Yankee stadium fits in. He explains:

The analysis begins by recognizing that in a vacuum, all balls hit with the same initial velocity and launch angle will travel the same distance. In reality, the ball will travel more or less than that, depending on the influence of the aerodynamic effects of drag and the Magnus force, including any influence of wind. One way to define the “carry” is the ratio of the actual distance to the distance it would have traveled in a vacuum.

Here’s the chart Yankee Fans will be most interested in. “Normalized carry” refers the average way that a ball travels across all of Baseball.

(BTW-Note how far ahead Colorado is as compared with all other cities)

As you can see, the new Yankee Stadium is on the low end in terms of how the ball travels there, and is actually in the bottom fifth. So while it is indisputable that the Yanks are hitting a ton of HRs at the new stadium, and are likely to set a franchise record this year, it doesn’t appear to be due to wind effects.

That leaves us looking at other explanations. We know for a fact that they straightened out the curvature in the Right field wall, making it a few feet shorter between the numbers on the wall. See chart below (from WasWatching):

And here’s the Hit tracker data on where HRs have landed:

As the chart shows, clearly many balls have been HRs in the new ballpark that would have been outs or doubles in the old facility. As is often the case, it appears the simplest solution is the correct one. The Right Field wall is simply shorter than it has been in years past.