[BULK] - RE: [pct-l] Campo to Morena Day Hike (was16+mi.drystretches)

[tahoe.cat at verizon.net (Cathy)]

Oilcan's ancestors must have caused it.  Ground Pounder Bill
----- Original Message ----- 
From: "Jeff Moorehead" <jeffmoorehead1@cox.net>
To: <pct-l@mailman.backcountry.net>
Sent: Monday, February 07, 2005 5:49 PM
Subject: Re: [BULK] - RE: [pct-l] Campo to Morena Day Hike
(was16+mi.drystretches)


> wow that was some explanation of katabatic-- although the previous post
> (Judson) did correctly point out that Antartica is characterized by nearly
> constant katabatic winds. i learned this as i tried to come up with an
> explanation that would never have been as lucid as yours... good thing i
> didn't try. we can still blame Oilcan for the cold winds??
>
> I'll try 'adiabatic' though and then you can correct me. Adiabatic (as
> opposed to isothermal) refers to a disequilibrium in heat transfer
> charcterized by the thermodynamic equation PV=nRT where P=Pressure and
> T=temperature. The practical effects that we all experience is the warming
> of the air as we descend to lower elevations (higher baromaetric
> pressure).Conversely, air cools as we gain elevation, which makes for a
> normal temperature-elevation profile. So when katabatic conditions exist,
> the normal profile is 'inverted'. The 'adiabatic lapse rate' depends on
the
> moisture contained in the air. The dry lapse rate is steeper than the wet.
> If you descend into the desert from the dry side (east side in CA) of
> mountains, the temperature increases at a rate faster than it was
decreasing
> as you climbed the west side. That's why the deserts to the east of the
> Sierra are not only dry (the rainshadow effect) but so damn hot!
> how can we pin this one on Oilcan?
>
>
>
>
> ----- Original Message ----- 
> From: "Brett" <blisterfree@isp01.net>
> To: "Judson Brown" <judson@jeffnet.org>; <pct-l@mailman.backcountry.net>
> Sent: Monday, February 07, 2005 5:33 PM
> Subject: Re: [BULK] - RE: [pct-l] Campo to Morena Day Hike (was
> 16+mi.drystretches)
>
>
> > >I think katabatic refers to strong, cold winds which occur in polar
> > >regions,
> >> especially over ice caps. Antarctic explorers had to deal with them
> >> constantly.
> >
> > Katabatic has nothing to do with acrobatic mountain lions. It's simply
the
> > colder and thus heavier air that sinks into low lying areas, most
commonly
> > in the evening and overnight hours when heat radiates away from the
earth
> > at a faster rate than it is absorbed. It is not a
geographically-specific
> > phenomenon, although it tends to occur most noticeably in mountainous
> > areas where the lower-lying drainages are natural conduits for the cold
> > air from the heights. Katabatic air acts like a mini-river that, in
fact,
> > often "flows" just above the actual rivers. Or creeks. Climb away from
the
> > creeks before selecting a campsite, even as little as 10 or 20 feet
above
> > them, and avoid much of the katabatic cooling effect. Sleep warmer.
> >
> > Now who wants to explain "adiabatic"?
> >
> > - blisterfree
> >
> > -----------------------------------------------------------------------
> > Simblissity Ultralight :: One-of-a-Kind Designs for the Great Outdoors
> > www.simblissity.net
> >
> >
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