[nafex] Global warming froze my garden...
redherring at tnaccess.com
redherring at tnaccess.com
Sat Mar 23 09:13:51 EST 2002
I had to cover my greens and peas these last 2 nights, anything
uncovered got creamed. Still remains to be seen about peach buds, but a
couple of plums were foolishly in bloom already. The Bradford pears in town
have gone brown. Here in Tennessee we expect up and down temperatures in
the spring, but it's only in the last few years that I have seen my
daffodils turned to mush by freezes.
I have been suspicous about the CO2 connection to global warming because
climate records shows extreme changes before the internal combustion engine
was invented. In fact, back in the mid 70's Rodale Press did an editorial
on climate change. They said that the world had been in an unusually stable
weather pattern for the previous 200 years, and especially so the previous
40 years. They found it ominous that hybrid corn and monocropping with
plants that were practically all one clone had been developed during that
time frame. Their answer to the question, "Will it get hotter or colder?"
was that it will do both. They did not really have an explanation for WHY
the climate was normally prone to fluctuations.
Now what we are reading is that changes in the sun are behind "global
warming". We had an unusually high number of sunspots on this cycle, and a
double peak. I'm not sure it's over even yet, NASA keeps saying it's over,
and then there are even more sunspots. We read a report a month or so ago
saying that when sunspot numbers are high, ther is less cloud cover. this
would account for much of our warm winter so far. The report said that as
sunspot numbers dropped, we would have a Feb and March colder than usual.
In fact, I'll copy some of the article here.
I'm afraid that writers for Pomona may not have much to say about
their fruit crops in 2002. Maybe it will be a year for writing about garden
huckleberries (yechh!!!) and ground cherries. I've tried them in cobblers
with apples, and the ground cherries are pretty decent. Actually, Peters
Seed and Research had some sweet huckleberries that were pretty good, but
the dang blister beetles chewed our plants up.
Donna, TN, Z6, thought I was in Z8 back in January
"Will Winter Make an Appearance in February and March?"
January 24, 2002 By Joe D'Aleo
Chief WSI/INTELLICAST Meteorologist >From Intellicast
As we also showed in the last story
http://www.intellicast.com/DrDewpoint/Library/1281/, the atmosphere is about
as ash and aerosol free as it has been at any time since the 1950s
(according to NASA GSFC estimates). That means even small changes in solar
input can have more impact.
In high solar flux winters, temperatures have, more often than not, been
warm, consistent with the enhanced Pacific influence. 6 of the 9 winters
averaged above normal for the nation as a whole, most well above normal.
With a tendency for more of a zonal flow, air in the Polar Regions is
trapped and gets increasingly cold, while to the south of the jet stream
warms. This increases the thermal contrast from north to south and the
resultant energy of the jet stream. In some months during active solar
periods, the flow has buckled in a big way, delivering a period of extreme
cold (December 1980, December 1989). But in these years, it was more than
offset by warm weather in the other months when the pattern broke down.
There is one more factor that becomes important - snow cover. With the cold
air to the north, and steady stream of storms, snow cover built across
Canada. Snow has a high reflectivity (albedo). It reflects back much of the
radiation (of course that is small this time of year) that does reach the
surface, keeping it cold. But to the south of the storm track, westerly
winds and the downslope warming brings about bare ground. The bare ground
heats up more with the solar radiation. The net effect is to strengthen the
gradient of temperatures and pressure along the boundary of this snowpack.
This positive feedback process maintains the storm track and conditions
until some large-scale change disrupts it.
During high solar flux periods, there is also less cloudiness thanks to the
"Svensmark" effect, named after the Danish Meteorologist who proposed the
connection. When the sun is active, the earth's protective magnetic field is
strongest. This blocks the passage of cosmic ray neutrons into the
atmosphere. It has long been observed that the number of neutrons received
at the surface is significantly lower then at the solar minimum. Since these
neutrons have an ionizing effect that enhances clouds, their reduction leads
to less cloudiness at the maximum than at the minimum. In the regions the
Danish meteorologists studied, the cloudiness difference was on the order of
3 percent. Since clouds reflect solar energy back to space, there is more
sunshine, more solar warming and perhaps higher temperatures. If you live in
the northern states, you may notice more sunshine than normal in a typical
northern winter. This year has been sunnier than normal in the northern
states and this may have been one of the causes.
A few of the solar scientists I have communicated with about the current
solar resurgence indicated that they would anticipate, based on past
behavior with the second maxima, that the activity would drop off rather
quickly in the next few months. Still, given current levels, one might
expect the solar activity to remain "a factor" to be reckoned with. If it
continues to be important, there are signs in the historical database that
the pattern will finally adjust to enable cold air intrusion into the lower
48 states within the last two months (of winter). If the solar factor is
important, some of the Canadian cold air will infiltrate the states in
February and settle in the Southeast in March. This may be enhanced if El
Nino comes on.
So you ask why we didn't see this coming. Well, we had diminished our focus
on the solar factor after it peaked in early 2000 and then dropped off last
winter to moderate levels. Most of the predictions of solar sunspot and
solar flux activity had the decline continuing another 10 percent this
winter. When it spiked in September and October, we did not get too
concerned because activity during the solar cycle normal shows a fair amount
of month-to-month variability. But it did not drop off.
And El Nino/La Nina?
We continue in a hybrid situation with cold water in the east and warm water
in central and western areas of the tropical Pacific. I guess it should not
surprise us, given this hybrid state, that the jet stream pattern has
"toggled" back and forth between one suggestive of El Nino (a positive PNA)
and another suggestive of La Nina (a negative PNA). This fall and early
winter, we have alternated between the two states about every 2 to 4 weeks.
The PNA or Pacific North America Index is an index that measures the
pressures relative to normal over the eastern Pacific and North America.
Tracking the PNA is useful because given the orientation of the land and sea
and western mountains, the pressure pattern and associated jets stream
usually falls into one of two categories. The positive PNA with a trough off
in the Pacific, a ridge near the West Coast and a trough in the East; or a
negative PNA with a ridge off the West Coast, a trough in the West and a
ridge in the East.
Based on ocean temperatures in the Atlantic, which are clearly in a mode
that correlates with a negative NAO, I feel that the NAO will tend neutral
to negative for much of the rest of the winter. Should it swing to strong
negative, that could mean this time we would see more of the cold and snow
we typically find with a negative NAO because now the cold air is poised in
Canada ready to be tapped (that assumes of course it doesn't suddenly dump
into the Atlantic).
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