[OKDXA] South Orkneys

[Rick vidmar - k9kk]

S9DX will be there thru FEB 17th.
Also now time to work
TJ9PF Cameroun.
Gud luck
K9KK Rick

On 2/11/2011 11:16 AM, Kimberly Elmore wrote:
> Off-topic alert!
>
> Good observations, Nelson! Yes, the OK mesonet site has a wealth of information
> on it, all for the asking. I may be mistaken, but I think that the temperature
> and dewpoint all come from sensors at 2 m above the ground, while the wind comes
> from sensors at 10 m, but I'll have to check with the OCS staff here.
>
> Yep, when I rode a motorcycle I, too, noticed the changes in temperature with
> elevation, especially in the evenings and at night. If you think back, you'll
> also remember that these changes were apparent only when the wind was nearly
> calm. Great stuff!
>
> The short-period changes you see in the night time temperatures aren't due to a
> change in the enthalpy (thermal mass, if you will) of the air, which remains
> remarkably constant despite relative humidity. If you look carefully, you will
> usually see the spikes in night time temperature are also accompanied by small
> puffs of wind. These puffs of wind represent momentum transfer from aloft,
> somewhere above the night time surface layer. Under light winds, that layer
> becomes decoupled from the flow aloft. But, occasionally turbulent mixing brings
> down some momentum from above the surface layer, and we get not only a puff of
> light winds, but also a puff of warm air.
>
> This is why, especially in winter, if the winds stay up at night, we don't see
> the big swings from low to high temperature. Turbulent mixing in the vertical
> prevents the formation of a cold, decoupled surface layer due to radiation.
>
>
> No, this isn't DX, but it is fun stuff!
>
> Now, back to the South Orkneys!
>
> I still need S9DX on more bands. How long will they be there?
>
> Kim N5OP
>
>
>
> ----- Original Message ----
> From: Nelson Derks<ac5up at windstream.net>
> To: Discussion of OKDXA<okdxa at mailman.qth.net>
> Sent: Fri, February 11, 2011 10:43:12 AM
> Subject: Re: [OKDXA] South Orkneys
>
> Jay Eimer wrote:
>> I saw the same thing on my commute yesterday morning.  My truck has a
>> thermometer display.
>>
>> I live on a hill - and saw 0 at my house (on top of the tallest hill in the
>> immediate vicinity).  But I saw 10 degree swings as I dropped into valleys  -
>> down to -11 at one point, -7 or -8 more typical at the bottoms, and -2 or so on
>> the crests.
>>
> Speaking as an aging motor scooter pilot I can tell you that's nothing
> unusual. In the summer when it's hot it tends to be hot no matter what
> or where, but in the spring&  fall when you drop down a hill to cross a
> bridge over a creek there is definitely a pocket of cooler air near the
> water. Can't miss it. It's also noticeably cooler in the shade except on
> very humid days when there is no escape from the heat anywhere...
>
> As for the latest, if you have some spare time go up to the mesonet dot
> org site and click "weather" up top. Choose a monitoring site that
> interests you (if you park your mouse on any orange dot the name will
> pop up). Note the stat summary and abbreviated forecast, then click on
> the meteogram (green&  pink graph) toward the upper right corner.
>
> What you're looking at is time on the horizontal axis and temp displayed
> vertically in three ways by color overlay: Actual temp, dewpoint and
> wind chill. All are measured at 10 meters above ground. Park your mouse
> along any boundary line and it will pop up the time, temp, and whether
> the number is wind chill or whatever. Notice in the upper right corner
> how you can go back 1, 2 or 3 days in time. Also notice the graphs for
> wind speed, direction, yadda, yadda, yadda.
>
> Point of all this is that you have a buttload of readings in five minute
> increments and the overnights have become very 'spikey' on the
> temperature graph. Best guess is that the air is so dry it has no
> thermal mass (thermal inertia?) which is contrary to normal conditions.
> Generally the humidity rises overnight and temp changes become more
> gradual because of the moisture. Looking at Bixby in the wee hours of
> the 10th I'm seeing two and three degree deltas within a 5-10 minute
> spread in both directions. Note also how the very coldest portions of
> the morning were relatively short lived and I think that's fortunate...
> When I saw it was around -20 at my QTH my next move was to check for a
> green puddle under the car. None found. The temp was cool enough to test
> the ol' ethylene glycol but not the exposure time. Takes a while to suck
> all the heat out of a proper engine block and Jack Frost didn't get a
> good grip on mine.
>
> Poke around the mesonet site and you can find all sorts of groovy things
> like soil temps and month by month archived summaries from each
> measurement site. If a person has the need they can research both long
> and short term trends, and I predict the overnight temperature lines are
> going to smooth out nicely in the next day or two................
>
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