Wednesday, August 30, 2006


At this time of this particular year, I've been reading this blog occasionally, and by occasionally I mean not more than six or seven times a day.

And it turns out the Sam Wells, Sphere's most prolific commenter, has his own blog, from South Padre Island, Texas, where you need a hyper-immunity to humidity in order to survive. Here's Sam's blog.


Blogger Sam said...

Hey thanks for the link, Tom. Really, this is a creative fun blog for me, and I tend to blow off steam that way.

As to the "uber-humidity" comment I'd like to address that one - you know I couldn't resist! The area along the eastern seaboard is actually wetter than down here ... we are in a severe drought.

Let me explain. Relative humidy is the ratio of water vapor to saturated air, such as by using a hygrometer. Surely enough, along the lower Gulf of Mexico relative humidities can be very high, especially during the cooler hours of the day.

But the real McCoy is called absolute humidity. That is measured in terms of kilograms per cubic meter of air (the old method was grains of H2O per pound of dry air). Often there is little corelation between relative and absolute humidity in some areas and some times.

It is a fascinating subject and some climate experts have been taking a fresh look at absolute humidity in the context of Global Warming. For my purposes, it was to evaluate NOx formation from diesel engines, since higher water wapor (absolute) can actually lower NOx exhausts by "quenching" the oxidation reactions. This was done more in the context of regional ozone air quality modeling.

To make a short story long, Houston did seem to have extremely high absolute humidity scores based on coastal weather stations (it dropped very fast inland). I did a crude analysis to find out that 30-year climatology values for Seattle and New York absolute humidities were even HIGHER, though. I did this because I was astounded at how much water vapor can be mixed into the air.

At that time, I had 1998 absolute humidity data obtained from my weather dudes via a large UNIX system. It was perhaps a good fraction of a terrabyte in size, so I asked for 12 Texas counties and a couple other US cities so I could process the data on a PC using SAS, only a few megabytes in size.

I wish I had kept the data but if you track temperature, pressure, relative humidity, and absolute humidity, the results can be the opposite of what one might think, humidity-wise. Regards,

9:10 PM  

Post a Comment

<< Home

eXTReMe Tracker