Sunday, June 21, 2009

Cheng for Dummies

One of our frequent commenters, Wearhing a Halo (WAH), suggests that I have misunderstood Dr. Cheng's testimony. To quote from his comment:

"At best Dr. Cheng mispoke and at worst Dr. Cheng was misquoted by the court reporter/transcriber when Dr. Cheng said '40 knots (kn)'. It is my contention is that Dr. Cheng meant "40 kilometers (km)". 40 km fits with the data where 40 kn does not. If Dr. Cheng did state 40 kn . . ."

So, let's discuss this possibility.

First, let's start by reviewing what Cheng actually said:

"I felt that was, wow, quite a wind event during that day. I really recall in my own mind, you can see now the scientific records showed us now during that particular period of time, in the morning, or starting from the midnight of the midnight April 11th, or early morning of April 12th, you can see wind exceeded 40 knots. 40 knots, wind exceeded. Also a sustained wind for long period of time, subsided slightly, but still continued on for another good twelve, eighteen hours with wind average around twenty knots per hour."

Cheng actually repeated 40 knots. Now, sometimes he did misspeak, but then corrected himself. He repeated 40 knots, to emphasize it, in my opinion, not to correct it.

Second, the transcript spells out the word knots; the abbreviation kn is not used, so it's not a simple case of the Court Reporter mishearing or making a typo. Knots is a one syllable word; kilometers is a 4-syllable word. Knots doesn't sound anything like kilometers. I really don't think a Court Reporter could hear kilometers and record knots.

Third, when do Americans ever measure wind speed in kilometers? How many Americans even know what a kilometer is? Well, I checked, just to be sure, using a handy online converter.

40km per hour = 24.9 mph.

Yes, WAH, that significantly reduces the wind speed, as 40 knots per hour equals 46 mph. So this "wow, quite a wind event" has gone down from 46 mph to 24.9 mph.

But does that mean we then have to refigure the sustained winds for 12-18 hours of 20 knots per hour? 20 knots per hour which converts to 23 mph really should have been 20km per hour, which converts to 12.4 mph. I know people in the Bay Area can be really whimpy when it comes to wind events, but calling 12.4 mph winds a "wow, quite a wind event" is beyond whimpy.

But then we have the characterization by Distaso. Initial winds of 24.9 mph followed by sustained winds of 12.4 mph equals a "very violent storm" as Distaso called it in the State's Closing Argument? Talk about hyperbole.

WAH, I readily admit, 12.4 mph much better describes the "wow quite a wind event" on April 12, but does that really help the State's case? I don't think 12.4 mph winds qualify as a "wow, quite a wind event/very violent storm" for the Bay.

Keep talking, WAH. I'm sure Scott appreciates your efforts to clear up what Cheng really meant and to expose the truth about the storm as well as the hyperbole in Distaso's characterization. Let's see, I seem to recall that to intentionally misrepresent evidence is prosecutorial misconduct.

Any one have a larger petri dish handy?