Davis
Instruments Weather Club
August 2003
In This Issue:
Crazed
Hordes Descend on Davis’s Clearance Center
Wow. The July
E-News, with an announcement about our new Clearance Center, was
sent out and a matter of hours later several of the virtual shelves
the Clearance Center were almost bare! We must say, the deals there
are too good to pass up – and you all sure didn’t! In fact, we are
sold out of a few items, including the EZ Mount Weather Wizard and
EZ Mount Weather Monitor II stations. But, there are still plenty
of bargains to be had, so if you haven’t already paid a visit, check
out the Clearance
Center.
Maybe It Was Mars Mania
You’d have to
have been on Mars lately to have missed the Mars Mania that has
infected the world. People are buying up telescopes and orange filters
in the hopes of getting the most out of an unusual opportunity to
view the Red Planet. On August 27, Mars will come right up and nudge
the earth -- almost. It will come within 55.76 million km (34.65
million miles) to our own Blue Planet, the closest it’s been in
many a millennium.
Even if you
don’t have that fancy telescope, it would be hard to miss Mars right
now. While not the biggest, it is the brightest thing (except for
the moon) in the sky, glowing a nice orangey-yellow in the southern
sky (for the Northern Hemisphere). Even with poor viewing conditions,
you should be able to pick it out of the murkiest night sky. If
you do have a fancy telescope, you might be able to see some Martian
features such as volcanoes, craters, dust storms, and the Martian
polar ice cap. The ice cap, a chunk of frozen CO2,
is melting fast, but its highly reflective surface makes it easy
to see.
Astronomers’
explanation of why Mars is so close right now is quite complicated.
It has to do with the fact that Mars and Earth both travel orbital
paths that are neither perfectly circular nor unchanging from year
to year. Sky & Telescope’s illustration, (see below) helps
simplify the explanation. 
The orbits of
the Earth (blue) and Mars (red) around the Sun. Mars moves in a
noncircular orbit, and it will be closest to the Sun precisely when
Earth moves past it on August 27th. On that date at 5:51 a.m. Eastern
Daylight Time, the two planets will be only 34.6 million miles apart
— their closest pairing in nearly 60,000 years. The sizes of the
Sun and planets are not to scale. Sky & Telescope illustration
by Steven Simpson.
But even more
complicated, it turns out, is figuring out when the last time Mars
came this close. Roger Sinnott, senior editor of Sky & Telescope
asserts that the date is 57,617 BC. According to Sinnott's
article, Aldo Vitagliano, an expert in computational celestial
mechanics (our second choice for our college major) arrived at this
date after integrating the orbits of all nine planets, the Moon,
and three asteroids, then letting his computer whir away for three
hours of computation. Back in 57,617 BC, Mars was just a bit closer
than it will be on August 27, 2003 AD.
Start looking
right now. Dust storm season on Mars is just approaching and might
hamper the best views. Miss it, and you’ll have to wait for the
next time Mars will be almost as close: August 28, 2287. Weather
Check Quiz Question 1: Roger Sinnott writes that the last time Mars was so close was in the year 57,617 BC, which he states was 59,619 years ago. If you add 2003 to 57,617, you get 59,620. Did Roger flunk Math 101?
City
Folks Live In An Island Paradise?
City dwellers
may be taking off part of the summer to loll on some real island,
like Cozumel or Oahu, but they really don’t have to. A recent article
in Time magazine,
reminded us that we city people live an island life already: we
live in Urban Heat Islands. The phenomenon of Urban Heat Islands,
which has been recognized for more than 100 years, comes from the
fact that cities produce their own heat, and thus their own little
microclimates.
In the countryside,
much of the sun’s heat is used in evapotranspiration – the movement
of water from soil or plants to the air. This creates an evaporative
cooling effect. The relatively level ground surfaces also promote
cooling and air mixing.
But in the city,
much of the sun’s heat is absorbed by asphalt and structures. In
addition to the absorbed heat from the sun, even more heat is generated
by the city’s vehicles, industrial processes, and domestic heating
and cooling. When night falls, the absorbed heat is slowly released
into the air and often kept closer to the surface by the presence
of vertical walls of structures and the not uncommon occurrence
of an inversion layer. The result is that the city is often several
degrees warmer than its rural neighbors.
So what,
the uniformed might say. A few degrees here or there won’t make
much difference. Not true, we weather lovers all holler! A few
degrees are all it takes to affect the weather in and around cities.
We all know
that air travels from high to low pressure; warming can create a
low pressure cell above the city which leads to breezes from the
rural area toward the city center. As industrial areas are on often
on the outskirts of town, this means that pollutants can be concentrated
in the city center.
The temperature
change can be enough to affect thunderstorm formation and precipitation
amounts. People who live in rural areas downwind of a large city
are much more apt to be treated to thunderstorms than those on the
opposite side. Rainfall may be higher in the city than in the surrounding
areas.
On a human level,
a few extra degrees in the summertime means increased discomfort
(and health risks), and this means increased power demands as people
crank up their air conditioners.
But possibly
the most important aspect of Urban Heat Islands, is the increase
in smog created by the temperature increase. The formation of smog
is very sensitive to temperature. Add to this the presence of an
inversion layer above the city, which acts like a blanket, and you
get a further reduction of air mixing and even less disbursal of
the smog.
Pollution itself
can affect the weather directly by reflecting sunlight and providing
nuclei for the formation of water droplets, fog, and ice.
As cities get
bigger, it becomes more and more urgent that we look at ways to
mitigate the effect our cities have on the weather. The EPA and
the Department of Energy (DOE), among others, recommend that vegetation
within cities be increased, as well as encouraging the use of reflective
materials in construction.
So if the canyons
you prowl are mostly made of steel and brick, plant a tree!
Weather
Check Quiz Question 2: How has the phenomenon of Urban Heat
Islands been used to downplay the evidence of global warming?
Davis Weather Station Helped Explain Why Visitors “Feel Strange” on Venezuelan Mountaintop
Dr. Carlos Rivero-Blanco and his wife Machela installed a Davis weather station in the small nature center they staffed in Mucubají, Venezuela. Until they left a few years back, the station served as an educational exhibit for visitors to this high mountain ecosystem in the Sierra Nevada National Park. The park is the largest of 12 national parks in the Venezuelan Andes. Since returning to Caracas from Mucubaji, the Rivero-Blancos have set up a “homemade” website to record their many memories of Mucubají.
The Mucubaji Nature Center sits high in the Andes, in its own little microclimate.
“Mucubají is
very much like the ‘top of the iceberg’,” Dr. Rivero-Blanco wrote,
“if we talk about Venezuela, a country which can be as cold as Mucubají
or as warm as our great tropical rain forests.”
Mucubají, at
about 8ºN, and 11,440 feet (3,550 meters) above sea level, offers
a unique climate of year-round cool temperatures and high humidity.
The mean temperature is 5º – 6ºC (41º - 43ºF), with precipitation
up to 1200 mm (47”) a year. Seven months out of the year are rainy.
While Mucubají’s proximity to the equator makes for limited seasonal
variations, the weather can swing wildly in the space of day, sometimes
going from a chilly -8ºC (17ºF) in the morning to a warm 22ºC (72ºF)
in the afternoon. Needless to say, weather information is basic
to understanding the ecosystem of Mucubají.
”In Mucubají,
the climate is particularly active and changing every moment,” Dr.
Rivero-Blanco writes, “and if you add to this the fact that every
visitor is coming from lower elevations, the way they feel when
they reach 11,440 feet -- with the cold, the low pressure, and all
other environmental factors pressing hard on human nature -- is
something to notice and worry about. It is at this moment when having
a Davis station permanently connected to a PC comes in handy to
explain why you are feeling the way you are. It really was our best
interpretive companion up there.”
Mucubají is
part of a unique and rugged land steeped in the creation legends
of its local residents. In fact, Mucubají’s deep, 10,000-year-old
glacial lagoon is said to be protected by a Great Serpent, who does
not like his lagoon to be disturbed. With people like the Rivero-Blancos,
whose love for that land is obvious, and the Venezuela National
Park system to help protect it, we hope the Great Serpent will rest
easy for many more years to come.
Weather
Check Quiz Question 3: In a fantasy version of last week, we
trekked up to visit Mucbaji and camped out under the stars, watching
Mars wander across the sky. But we didn’t do much sleeping. We had
to get up several times to visit the latrine, the minor exertion
of which left us a bit breathless. And when we did drift off, we
had some really strange dreams and kept waking up. Our campmate,
who also couldn’t sleep well, said we were breathing funny. What
was wrong with us? Are we going to die, Doc?
Western
Washington Weather Watchers Wanted
Ted Buehner,
the Warning Coordination Meteorologist of the Seattle NWS office
is in search of weather data from western Washington. He is looking
for those who are already posting their data on the web, and plans
to share the information with the University of Washington’s Atmospheric
Science Department, as well as with NWS staff to help add to a collection
of mesonet data.
If you are
posting weather from a western Washington location, you can contact
him with your URL at Ted.Buehner@noaa.gov.
Davis
Helps Bentleys Go Fast
Last year we
told you about some Davis weather stations helping out at the auto
races at Le Mans. A UK company, RaceMet Radar Services, was on site
at Le Mans, with their Davis stations, to help drivers tune their
engines. Alistair Barron, of the UK Weather Shop, wrote to tell
us that this year RaceMet was there once again, working for Bentley
at Le Mans. He filed the following report on their success:
“Once again
the cars came home first and second. This was the culmination of
a three-year program and the first time Bentley has won at Le Mans
in 73 years!
“Part of their
success was being able to start on the right tires. There had been
severe storms to the south and east during the previous few days
and it rained much of Saturday morning. While the track was drying
coming up to the start at 16:00, many teams were unsure of what
tires to start on. This problem continued after the start into the
night with the threat of rain ever present.
“With their
[radar] equipment, RaceMet can see rain up to 96 miles away and
with the wind direction, humidity, temperature and barometer data
from their Davis weather station overlaid on the radar screen, they
can warn the team of impending rain. Of course this information
helps the team have the right wheels and tires prepared for each
scheduled pit stop every 12 or so laps, as well as for any changes
of condition in between.
“I visited
Racemet’s installation near the Le Mans pits. They had a neat air
conditioned trailer that was a welcome haven in the 30ºC daytime
heat of the race. From here, they also provided the team with weather
data for engine and chassis tune before and during the 24-hour race
as well as details such as track temperature on the different tarmac
types around the 8.46 mile course.
“The winning
#7 car, driven by Tom Kistensen, Rinaldo Capello and Guy Smith started
from pole and completed 377 laps, that is 3190 miles at an average
of 133 mph! Its sister #8 car finished in second place just two
laps behind and put in the fastest lap of 3'35"529, or 143 mph,
in the hands of Johnny Herbert.”
Go Bentley!
Weather
Check Quiz Question 4: Ozone in the air we breathe is a bad
thing. Breathing air polluted with ozone can lead to shortness of
breath, coughing, headache, nausea, eye irritation. Americans spend
$50 billion a year on health care necessitated by ozone. But ozone
is also bad for which part of your car?
Our
Readers Embarrassed and Confused, But They Know Their Stuff
Those dinosaurs
just won’t die! In our last issue, reader Paul Grace got us thinking
about the speed of things, specifically, just how fast the dinosaurs
in Utah got roasted after the impact of the big meteor off Mexico.
But Paul Benvenuti
thinks the world would be a strange place if the speed of sound
was 350km/h, as Paul Grace asserted.
When we mentioned
this to Paul G., he answered by quoting that great thinker, Homer
(Simpson): “Doh!”
“He is correct,”
Paul G. wrote. “Sound travels at 350 meters per second, not 350
kph, so it would be .33kps, or 7,800 seconds, or a little over two
hours ten minutes, not 7.5 hours [for the dinosaurs to die after
impact]! DOH DOH DOH!!!” Paul Grace has a lovely website (which
he keeps running via satellite uplink) that details the weather,
wildlife and even history of his Lookout Ranch on the gorgeous north
coast of California.
Thank you Paul
One and Paul Two!
One Mr. McCune,
of Twin Oaks Community College in Louisa, VA, found a typo in our
last issue that had some interesting ramifications. We posed a Weather
Check Quiz question about who came up with the theory of hemispheric
trade winds. In our answer we wrote, “Back in the 1860’s, astronomer
Edmund Halley correctly suggested that the trade winds were created
by warm air rising near the equator, bringing a steady stream of
surface winds in toward the equator.” A simple twist of the phalanges
caused quite a bit of confusion: Halley was long gone in the 1860’s
-- we meant to type 1680’s! The strange part is that that another
brilliant guy, George HADLEY elaborated on this theory in the 1700s.
So not only does Hadley have a name that is just one letter different
from Halley’s, he also solved some wind mysteries and did so a bit
closer to our erroneous time frame. Thanks, Mr. McCune for the careful
reading.
On a happy,
no error, note, Trevor Atkins wrote to thank our readers for the
weather data his school has received from our readers.
“On behalf of
all the children at Eccles Primary School, can I say a BIG thank
you! I have already received five discs and we are really grateful
for your and your readers’ help.”
And finally,
Peter Hargadon appreciated our UV warnings. Peter, who has had two
skin cancer operations, uses his VP to prevent any more.
“Before I go
to the airport for sport flying,” he wrote, “I go to my Vantage
Pro.”
Weather
Check Quiz Question 5: For what theory is George Hadley best
known?
We
Didn’t Do It!
Like lots of
other folks, we run a constant battle against computer viruses.
Our IT department takes great care to insure all our emails are
virus free. We have four levels of virus protection on our email
from two anti-virus software makers and virus definitions are updated
on an hourly basis.
Some worms,
like the recent “Sobig” worm, “forge” the “From” address field so
that those who receive them don’t know where they actually came
from. Recently, we’ve had a few reports that a Sobig worm-infected
message has arrived in the mailboxes of some of our readers with
our name “forged” in the “From” field.
Well, it wasn’t
us! If you got one of those messages, even though we didn’t send
it, we apologize! And from our IT department to yours: The only
way to stop viruses and worms from spreading is to make sure you’ve
got good virus protection! The ultimate guide to virus protection
has to be Symantec. Their Anti-Virus Research Center is an excellent
resource.
You're
Brilliant! Answers to Quiz Questions
Question
1:
No, he’s brilliant! He knows there was no year 0. At midnight on
Dec. 31, 1 BC, the calendar moved to Jan. 1, 1 AD. Sorta. (Anyone
who sends an email saying there were no calendars back then will
be ceremoniously e-tarred and e-feathered.)
Question
2: Since most weather stations are placed near where people
live and work (which tends to be in cities), some have suggested
that the data on global temperatures may be skewed by Urban Heat
Islands. (So says Dr. Mel Goldstein, in The Complete Idiot’s
Guide to Weather.) But don’t get excited - our staff meteorologist
tells us that studies from satellite data and from surface data
corrected for Urban Heat Islands continue to indicate that global
warming is probably a sad reality.
Question
3: We’ll probably live to fantasize another day. We are,
at least in this case, normal. At 3,500 meters, which is considered
high elevation, everybody experiences physiological changes as part
of normal acclimatization. According to the High Altitude Medicine
Guide, the body must
adjust to the lower barometric pressure. Every breath brings you
less oxygen from the “thin” air. The lungs and heart have
to work doubly hard to keep the blood’s oxygen levels at normal.
This can leave you feeling short of breath, especially with exertion.
The kidneys “dump” fluid, causing increased urination.
In an effort to get more air, you may begin to hyperventilate, which
can lead to a sort of confusion of the autonomic nervous system
that controls breathing, causing you to breathe in an unusual pattern,
or even hold your breath– especially when sleeping. Our symptoms
are probably not Acute Mountain Sickness; certainly not the really
dangerous version: High Altitude Cerebral Edema. However, you’d
be wise to remember the mountain climber’s golden rule: “Any
illness at altitude is altitude illness until proven otherwise.”
Question
4: The tires. Rubber is composed on long chains of polymers, the links of which are broken by exposure to ozone. Tires exposed to ozone (and that’s all of those on a car….) eventually develop surface cracks called “ozone cracking” or “weather cracking.” Rubber manufacturers add “anti-ozonites” to slow this cracking. Too bad they can’t develop an anti-ozonite for the air!
Question
5: The Hadley Cell: an explanation of how heat from the equator
is disbursed over the planet. His model shows one “cell,” the movement
of which is driven by energy from the sun. In this model, warm air
at the equator rises, replaced by cooler air from the higher pressure
poles, creating a simple cycle of air moving on the surface toward
the equator, where it rises then turns toward the poles, where it
descends and continues the cycle. The “single cell” model did much
to increase scientists’ understanding of global winds, but could
not account for the effects of land and water, or the earth’s rotation.
The reality of winds is complicated by so many factors, that it
is still not completely understood, but Hadley gave us an excellent
starting point with his Hadley Cell.
Who You Gonna Call?
Each month after the E-News goes out, we receive messages back.
Sometimes the messages are in response to a story we shared; other
times they are a request for help of some kind. We read all the
emails, answer those we can, and pass the rest on to the appropriate
departments.
We think you
should know, though, that if you're interested in the fastest possible
reply, news@davisnet.com
may not be the best place to send your message. Questions about
how things work should be addressed to tech support directly at
support@davisnet.com.
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To request a catalog, you’ll find links for catalog requests
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Please continue
to send your comments, weather URLs, and story suggestions to news@davisnet.com.
We look forward to getting your comments and any responses you have
to the E-News. Member participation is what keeps the E-News alive
and kicking.
Well, that’s
it for this edition. You’ll be hearing from us again next month!
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