Freezing Level

OK, I had a friend in Ecuador call and tell me all the locals were talking about how the freezing and snow levels were further down the mountains than anyone could remember. I’ve just spent a few hours trying to find decent maps / information on snow and freezing levels in Ecuador. It’s not easy (probably in part as I’m mostly getting English language hits and don’t know how to get Spanish sites in Google.) But Ive found some.

First up, this map of freezing elevations. Notice that it shows the “freeze line in early January to be about 4500 m to 5000 m depending on where in South America you are looking:

South America Freezing Levels in Meters

Original Image from this site

OK, all well and good, but what does that mean? Is that really colder, or hotter?

Conveniently, these folks have been studying just that:

http://www.geo.umass.edu/climate/papers2/Bradley2009.pdf

Recent changes in freezing level heights in the Tropics with
implications for the deglacierization of high mountain regions
Raymond S. Bradley,1 Frank T. Keimig,1 Henry F. Diaz,2 and Douglas R. Hardy1
Received 10 February 2009; revised 9 July 2009; accepted 4 August 2009; published 4 September 2009

What they found was that freezing levels were rising from 1958 to 1990. On page two they have a nice graph (in B&W) that shows the January Freeze Levels as being 5000 to 6000 m. I’ve not figured out how to embed their graph and don’t want to put the time into it, so you get to ‘click the link’. The caption implies that the data are available somewhere at NCEP.

Figure 1. Mean free air freezing level heights (GPH in
meters) in (top) January and (bottom) July, based on NCEP
reanalysis data for 1977–2007.

They then make two charts for the top and bottom of the ice cap.

Figure 4. Daily maximum ventilated air temperatures
(hourly averages) for (top) Quelccaya Ice Cap summit
(5680 m) and (bottom) Quelccaya ice cap margin (5200 m).
The latter was extrapolated using an observed free air lapse
rate for the region of 5.4
C km1 (based on NCEP
reanalysis data).

The top is regularly just below freezing with excursions to 2 C in January.
The bottom is regularly above freezing with excursions to -2 C in about August.

So this says that 5200 M is expected to be about 4 C in January, and pretty reliably.

But we have that map up top saying that Ecuador is pretty much frozen between 4500 and 5000 Meters. In January.

So, that paper has pretty much shown, IMHO, that you can use the freeze level as a proxy for what is happening (at least during the last 30 year 1/2 PDO cycle) and that the present Freeze Level says that whatever it was they had measured as “warming” has now all gone away, and then some. They found about a 1/2 C “rise over time” and we’ve now got a several degree “gone all at once”.

The major flaw I see in this comparison is that I’ve got a very short term weather map, not a monthly average. It would be better to find monthly average freeze levels (preferable global and for over 30 years, but hey, I know that’s most likely just dreaming) and then see what’s happened to the freeze level since 1998. A giant steam shovel sized “Dig Here!” in my opinion.

What’s pretty clear to me out of all this, though, is that ‘eyes on the ground’ seeing low snow levels and ‘ears on the ground’ hearing locals say even the old guys don’t remember snow that low; those directly translate into freeze level data and provide a very good analysis that says “Things have changed. For the colder. Fast and hard.” And it has happened even at the equator.

Further, I’d speculate that a ‘thinner atmospheric depth’ as we’ve gotten out of this UV drop could well account for the freeze level being lower. Lowered freeze levels globally has just got to have an impact on the ‘warming’ vs ‘cooling’ profile of the planet. I suspect this is a key part of how the solar changes drive climate changes.

Subscribe to feed