Where there are not overt “fog gaps” along the California coast (and also, along the lowest latitude portions of the coast, where SSTs start to rise a bit), there can be some truly amazing mid summer thermal gradients. For example, there are places along the central coast and south coast, where you can literally go from 55 – 64 Deg F, with overcast, and possibly even local drizzle, to over 90 or even higher, over a distance of no more than 10 miles. When I lived on the south coast, 20 plus years ago, I used to sometimes want to get away from what is called the “June gloom” – days on end of coastal overcast that never burns off. Such a condition is actually caused by the combination of persistent oppresive heat inland, combined with a net Westerly (but not enough of one to cool the interior). I would quite literally hop in my car, overcast, low 60s. I would drive over the first range, 3000 feet tall. Even prior to reaching the summit I’d rise above the marine layer into the sun. There, it would be 85F. Crossing the summit, and dropping into a piedmont area (~ 1000 ft elev) which was not getting any of the marine layer, it would literally be 100 deg F. Nearly a 40 deg F gradient, over less than 10 miles.

Here is the figure showing the POS and NEG chronologies in Pisaric et al 2007

Wait a sec, is this a case of NEG vs POS responders, or EARLY vs LATE responders? Because look at the divergence pattern 1900-1920. It’s opposite of that observed in the late 20th c.: the POS are NEG and the NEG are POS!

On the link posted by jae in #79 – the number 1 place in CONUS for annual variation is Bishop, California. Bishop just so happens to be the closest major ground measurement station to the White Mountains.

#66. Paul, in some cases, they measure MXD and other things, but my impression is that the problem isnt under-determination but weak relationships. I’m going to post something interesting on a Rob Wilson site where both MXD and RW are available.

I wonder if you are alluding to something I’ve been thinking about. I wonder if the dendros have tried looking at some combinations of ring width and densities. Maybe something like G = aw + bd + e, where G is an artificial growth parameter, w is ring width, and d is either ring density or latewood density. It seems to me that during cool periods both w and d would decrease. During moderate periods, w would increase and d would be moderate; during hot times (down side of quadratic), w would be small and d would be large. Part of the divergence problem could be increasing temperatures. Average July temperatures at Alamosa, CO (about 6500 ft. elev.) are 18.3 deg. C, meaning that during the day, temperatures spend a lot of time over the 20-25 deg. hump of the upside down U in July. Tree line in CO is approximately 11,000 feet. Assuming the trees that are sampled are about 10,500 ft and the lapse rate is 2 deg. C per M ft., the average July temperature at that elevation could be about 10 deg. So, daytime temperatures could easily be over 20 degrees, even at that elevation.