View Full Version : I need a refresher course on temp/elevation
What is the number used for lapse rate? I am remembering it to be a loss of 3.5* farenheit per 1000 feet elevation gain.
garlic08
09-29-2009, 18:02
That's for dry air. For wet air it's 5 F per 1000', as I remember.
Doughnut
09-29-2009, 18:15
2 degrees C for every 1000' is standard lapse rate.
DirtBagger
09-29-2009, 18:38
Its 3.5 ish for dry air and 5 ish for wet air.
There is a formula - but don't ax me to firure it out.
I've always used 4 deg. F per 1000' under calm, low humidity conditions, but there are always qualifiers. Been plenty of times where higher elevations have been warmer than the lower elevations at the local level.
Graywolf
10-01-2009, 00:39
Its 3.5 ish for dry air and 5 ish for wet air.
There is a formula - but don't ax me to firure it out.
Theres a joke here but I'm gonna leave it alone:D
freefall
10-01-2009, 01:53
The normal lapse rate of tempurature is .65 C / 100 meters.
The dry adiabatic rate is 1C/100 meters and the moist adiabatic rate is .6C/100 meters.
Moisture contains heat so a dry climate (Rockies) will cool faster with change in elevation whereas a moist climate (Smokies) will change more slowly.
Here's a link to more information but the above gives you a general idea.
http://www.uwsp.edu/geO/faculty/ritter/geog101/textbook/atmospheric_moisture/lapse_rates_1.html
Thanks for the meteorology exercise. I'm a meteorology major but have taken a year off from school so this helps in staying in contact.
freefall
10-01-2009, 01:58
And if you are needing more precise measurements than that, you can carry one of these that will give you current weather info so you can make calculations.
Kestrel 400 pocket weather station: http://www.nkhome.com/ww/4000.html (http://www.nkhome.com/ww/4000.html)
freefall
10-01-2009, 02:02
I've always used 4 deg. F per 1000' under calm, low humidity conditions, but there are always qualifiers. Been plenty of times where higher elevations have been warmer than the lower elevations at the local level.
Yep, typically in low wind situations, valleys accumulate cold air as it sinks. This pushes the air that the earth surface warmed up into the upper elevations. Thus a cold valley with warmer slopes.