My latest hobby – the weather and my home weather station

Well, not really my latest, but the one I’ve been working on more than others.

At one point in time I did some chasing and was a trained spotter.  I’ve let the spotter certification lapse, but it still doesn’t cease my interest and wonder in Mother Nature and her wonderful crazy weather in Oklahoma.

I got heavy into PWS (that’s Personal Weather Stations for the acronym-challenged) when my uncle had a LaCrosse 2310.  In 2006 I purchased a LaCrosse 2310 as well that lasted two years, then I purchased a Honeywell TE923W.  I also bought software to monitor, and post stats and charts to a website.

The intricacies of siting weather instruments is definitely something that most of you will roll your eyes at.  Do you often wonder what the term “60 degrees in the shade” means?  It has to do with the standard of measuring air temperature by the weather agencies.  They have precise criteria where they place their instruments.  For one, it has to be in an aspirated shield, and in most cases, it’s in a louvered cabinet that is called a Stevenson Shield.  Otherwise, if you place an instrument out in the open sunlight with no protection, what the weather office says is 60 degrees, winds up being 75 degrees because the case or enclosure you have the thermometer situated in is in direct contact with the daytime sun.

1. Now, a Stevenson Shield for most PWS hobbyists is a bit much.  I happen to have the CAD files for the certified NOAA Stevenson Screen, but after looking at it with my brother who is actually pretty good on AutoCAD, he informs me that it’s likely going to cost around $400 (do-it-yourself) to construct this screen.

The alternative is what is called a SRS (Solar Radiation Shield).  I purchased this for $34 US from Ambient Weather.

Here is the difference:

This is an SRS (Solar Radiation Shield)

This is a Stevenson Screen/Shield

The Stevenson is typically a ‘passive’ aspirated shield.  What that means is that the ambient air temperature (the real one you want to measure) is maintained using existing air circulation (just a fancy way for me to say wind, which I emit a lot of, I’ll freely admit to).

In most cases, where airport weather stations are sited, this will suffice, since it’s typically out in the middle of a field with little or no obstructions for several hundred meters in radius.  i.e. no wind breaks.

But, where this gets tricky with the personal weather stations is that, especially in an urban environment (in which I reside), there are MANY wind breaks and opportunities for what are called ‘microclimates’.  This could be as menial as road concrete or asphalt, patio concrete, heat radiating from out-buildings and utility sheds, or emanating from your house.  This can change the temperature in comparison to your closest official NOAA weather reporting station (which is likely the local airport..in my case, I have two).  Especially if that weather station sits’ at an elevation of 65 to 70 feet higher when only two miles away.  Yes, I live in a microclimate in the city, which does the following:

1. Wind deceleration.  This reduces the wind speed in comparison to the reported speed at the airport.  Caused by multiple buildings and trees.
2. Topography.  The valley tends to get cooler in the evenings quicker.  As I write this, my PWS is reporting a temperature nearly 4 degrees cooler than the nearest airport reporting station.
3. Buildings and drainage affect how the temperature and humidity is reported.

The main problem is locating the shield in a decent place.  Out in the middle of my back yard, about 4 feet above the grass.  Problem is, with all the windbreaks, the shield won’t aspirate properly, and in direct sunlight, a temperature bias (higher than the ambient air temperature due to radiational heating) of up to 10 degrees above the ambient occurs.

My solution was to artificially aspirate the shield.

How I managed this:

1. My SRS was used (first picture above, Ambient Weather’s SRS100LX
2. Since we know the problem manifests itself during the direct sunlight, I purchased a solar cell, rated at 12 volts.
3. Using an old PC fan (50mm, rated at 12v and 0.17a), I crafted a mount to place in the shields sensor chamber (if you look at the above photo, imagine the center of the shield having an oval cut out starting at the third plate down and ending at the 2nd plate up).  The thermo/hygro sensors gets suspended in this chamber with a graphite post that the sensor is strapped to.  I placed this mount at the bottom of the chamber, so it draws air out of the chamber.  This removes any built up heat in the shield, but the fan only runs if the sun is out.  The fan runs based on solar strength.  It needs at the very least 0.2 a to start, this usually converts into about 13v.  In full sunlight the panel generates over 20v.

Here are some photos of my setup:

Here’s the station console itself

The anemometer/directional

This is the rain gauge and UV sensor.  You’ll see more detailed images of the radiation shield below.

 

Here’s the finished product with the solar fan and radiation shield; some detailed photos are provided.  I have yet to fashion a permanent mount for the solar panel; that is something I am still working on.

 

 

Here’s a close-up of the shield.  You can clearly see the fan above the second plate.

Here’s a little closer shot of the fan.

An even better shot of the fan.

And here’s the finished (well, almost) product.  Still need to fashion a mount for the solar panel to put atop the post.

My Arena

As a lifelong Tulsan (aside from the three years I was temporarily insane and lived in Texas), I’ve always felt a sense of pride in my city.

None so much as lately, with the continuing construction of the BOK Center.

What is it?: a new convention center/arena. This city has languished in it’s old convention center, which, for a city in the 1960s, was sufficient. But the capacity of the Tulsa Convention Center was about 9100 for center stage events. Math tells you that is incredibly small for a metro area that is creeping up on 1 million people. Losing events to places like Little Rock, Omaha and Oklahoma City were becoming too much to handle. The new building will hold a little over 18,000 for center stage events.

On May 8th, I was offered the chance to tour the arena, still under construction, along with about 60 other members of a community website, Tulsanow.

The tour began at the Tulsa VisionBuilders office, with a short video that promotes the new arena, and some facts about it’s process from conception to construction.

Like the fact that Cesar Pelli (yes, the Cesar Pelli that designed the Petronas Towers) envisioned the design from a drawing of Native American mud huts that had a swirling, moving line to them.

The fact that OKC’s Ford Center still hasn’t sold out their suites. Five years after they have opened it. But Tulsa has sold out suites in a building that is still over three months from opening. And all 682 club seats are sold. Sold so well, as a matter of fact, that there is a waiting list over five years long.

Designs for the Premium Level borrowed from Balitmore’s Camden Yards, where in the BOK Center, you have Loge Boxes that lets you live a little more in luxury, but still feel connected to the crowd.

The fact that there doesn’t appear to be a single 90-degree angle in the building gives it a modern feel.

The fact that donations allowed for us to pay for an eight-sided plasma scoreboard, said to be one of, if not the, finest in the country.

A lot of Tulsans say ‘Why do we need this?’.

I say ‘What took so long?’.

Fast facts:

BOK Center capacity: 18,041
Designer: Cesar Pelli
Location: 200 S. Denver, Tulsa, OK
Cost: $178 million, funded by sales tax voted on by the County
Grand Opening: Sept 1 2008
Opening Act: TBD
Acts currently booked to play:

• Kenny Chesney with LeAnn Rimes – Sep 10 2008
• American Idol – Sep 13 2008
• Rascal Flatts with Taylor Swift – Sep 25 2008
• NBA Exhibition Houston Rockets vs Orlando Magic – Oct 13 2008
• Neil Diamond – Oct 21 2008
• Celine Dion – Nov 13 2008
• Celtic Thunder – Nov 19 2008
• NCAA Basketball University of Tulsa vs University of Oklahoma – Dec 6 2008
• Radio City Christmas Spectacular – Dec 22 2008

Out with the old, in with the new

 

Being forty, I have owned several vehicles throughout my lifetime. I’ve owned some older Pontiacs, some later model Fords (never again) and some older and later model Chevrolet’s.

My latest car was a 1995 Chevy Lumina that was in pretty good condition for a 10 year old car, and getting it for under $2000 was a steal, even if it did have ~120k miles on it. I added a neat little stereo with Sirius satellite radio, and had the vehicle from about April of 2006 on.

Then, in November, I noticed a slight ‘ticking’ noise in the engine, that almost sounded like lifter noise. If it was only that I’d be ok.

I had a week’s vacation, so I decided to take the car to someone to have it looked at. Bad news, the engine had pretty much worn itself out to the point that it could no longer maintain oil pressure. To fix the problem would cost more than the value of the car, which wasn’t much.

Let me begin the next section with the following caveat: I’ve never really looked in earnest for new vehicles. Never owned one, never really had the inkling to own one until this year.

My boss and good friend at work had recently purchased a 2007 Dodge Caliber, since the company we work for has a special discount rate with Dodge because our company uses DaimlerChrysler for their fleet vehicles. One percent off of factory invoiced (not MSRP) price. A little small for me, although I did like the car. The 2008 Avengers were coming out and I liked that line because they resembled the Charger, but didn’t have the sticker shock. I never really thought I would purchase one.

But I did.

This past Friday.

The most harrowing experience of my life was wheeling/dealing for a new car. I really wanted to build mine, but I have had some credit ‘issues’ in the past 5 years or so, plus with it being the end of the year I was told by both Dodge and this salesman that it would take nearly 12 weeks to finish the build. The salesman wasn’t a sleazeball, but the same person that sold my co-worker his new car. He made the process a little more bearable and worked with me.

So, on Friday, I nervously drove my first new car off the lot.

A 2008 Dodge Avenger SXT.

My Christmas present to myself for 2007.