More examples of the nighttime heat sink effect of UHI. Asphalt, concrete, bricks and other infrastructure holds the energy from daytime solar insolation and releases it at night as LWIR. Anyone who has ever stood next to a sun illuminated brick wall after sunset can understand this. The authors talk about the temperature record at SeaTac (103 degrees at SeaTac), but look where the temperature is measured. More on that after the press release.- Anthony
From OSU: New study finds “nighttime heat waves” increasing in Pacific Northwest
CORVALLIS, Ore. – A new study has found that heat waves are increasing in the western portions of the Pacific Northwest, but not the kind most people envision, with scorching hot days of temperatures reaching triple digits.
These heat waves occur at night.
Researchers documented 15 examples of “nighttime heat waves” from 1901 through 2009 and 10 of those have occurred since 1990. Five of them took place during a four-year period from 2006-09. And since the study was accepted for publication in the Journal of Applied Meteorology and Climatology, another nighttime heat wave took place at the end of this June, the authors point out.
“Most people are familiar with daytime heat waves, when the temperatures get into the 100s and stay there for a few days,” said Kathie Dello, deputy director of the Oregon Climate Service at Oregon State University and a co-author on the study. “A nighttime heat wave relates to how high the minimum temperature remains overnight.
“Daytime events are usually influenced by downslope warming over the Cascade Mountains, while nighttime heat waves seem to be triggered by humidity,” said Dello, who is in OSU’s College of Earth, Ocean, and Atmospheric Sciences. “Elevated low-level moisture at night tends to trap the heat in.”
In their study, Dello and co-authors Karin Bumbaco and Nicholas Bond from the University of Washington defined heat waves as three consecutive days of temperatures at the warmest 1 percentile over the past century. Using that standard criterion, they documented 13 examples of daytime heat waves during the time period from 1901 to 2009. Only two of those occurred in the last 20 years.
In contrast, nighttime heat waves have been clustered over the past two decades, with what appears to be accelerating frequency. A warming climate suggests the problem may worsen, studies suggest.
“If you look at nighttime temperatures in Oregon and compared them to say the Midwest, people there would laugh at the concept of a Pacific Northwest heat wave,” Dello said. “However, people in the Midwest are acclimated to the heat while in the Northwest, they are not. People in other regions of the country may also be more likely to have air conditioning in their homes.
On occasion, daytime and nighttime heat waves coincide, Dello said, as happened in 2009 when temperatures in the Pacific Northwest set all-time records in Washington (including 103 degrees at SeaTac), and temperatures in Oregon surpassed 105 degrees in Portland, Eugene, Corvallis and Medford. It was the second most-intense daytime heat wave in the last century, but lasted only three days by the 1 percentile definition.
However, that same stretch of hot weather in 2009 results in a nighttime heat wave that extended eight days, by far the longest stretch since records were kept beginning in 1901.
The latest nighttime heat wave began in late June of this year, and continued into early July, Dello said.
“Like many nighttime heat waves, a large high-pressure ridge settled in over the Northwest, while at the same time, some monsoonal moisture was coming up from the Southwest,” she pointed out. “The high swept around and grabbed enough moisture to elevate the humidity and trap the warm air at night.”
Dello frequently provides weather facts and historical data via Twitter at: www.twitter.com/orclimatesvc.
The Oregon Climate Change Research Institute is supported by the state of Oregon, U.S. Department of the Interior, National Oceanic and Atmospheric Association, and other agencies.
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The SeaTac ASOS, according to NCDC HOMR, is located below.
SeaTac is part of the GHCN network used for climate. But was it surrounded on three sides by heat holding asphalt in 1948 when the weather records began there?
Doubtful.
First Sea-Tac Airport Terminal, ca. 1946
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Ahem! Mr. Bradley, hm. I think we are talking about two different continents. My dear esteemed colleague, here is the quote from the “above article” that elicited my ridicule:
“some monsoonal moisture was coming up from the Southwest,” she pointed out.”
I THINK she was talking, in the article in general, about the Pacific Northwest of the United States. Your comment was full of interesting information. I wasn’t commenting on your comment, however.
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@ur momisugly MiCro — Oh. The smell of panic, eh? “Haylp! Haaaaaaaaylp! We’re burnin’ up in Seattle!”
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Dear Caleb,
LOL, fun and clever analogy. Thanks for brightening my evening with your highly creative writing. Heh, heh, I’ll bet those United Air Lines and Alaska Air Lines (and other lines) pilots would chuckle at the thought of their 757’s, 747’s and 727’s (all Boeing — OF COURSE) being likened to a pair of giant fat ladies lumbering around the tarmac. LAUGH — OUT — LOUD. Well, it’s not over until they sing…. heh, heh.
AND THEY NEVER WILL! America and freedom for—- EVER! (all the rest of the world, once it throws off socialism, TOO!)
Keep trying to get your writing published. It’s good.
Janice
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Hey, Jim S, hope all is well this lovely evening, down in Portland. LOL, I’ve been AMAZED to discover that not only is “climatology” recognized as a real word, the pseudo-scientists of Climate Science regularly CALL THEMSELVES that! Amazing. Freudian? At some level, they KNOW it’s a cult (to the true believers — not to the Envirostalinists and not to the cynical profiteers).
Thanks, Anthony.
Just another reason not to trust misplaced thermometers in airports or such locations.
Here’s a page of old photos from the port of Seattle: http://www.portseattle100.org/properties/runways As near as I can tell, the weather station would be near the corner of the dashed line runway labelled NW-SW Secondary at the bottom (west) of the top photo. The dashed lines were proposed runways, but the diagonal ones were never built. The 3rd runway would be about co-linear with the street at the bottom left of the photo. That’s 10th Ave So. My wife’s first boyfriend lived on that street.
Not enough airports: http://iceagenow.info/2013/07/12053/
Chris @NJSnowFan says:
“Commercial Jet travel was not around before the 1970′s”
DH Comet started commercial operations in 1952, Boeing 707 in 1958.
“some monsoonal moisture was coming up from the Southwest,” she pointed out.”
I THINK she was talking, in the article in general, about the Pacific Northwest of the United States. Your comment was full of interesting information. I wasn’t commenting on your comment, however.
The monsoon processes are basically the same everywhere. Ref Hadley Cells.
Humidity does not ”trap” heat. As the water vapour condenses latent heat is released which reduces the night time cooling effect.
Pacific Northwest Heat Wave. Translation: It stopped raining.
150 years ago the Pacific Northwest was rain forest with few people. It is still rain forest but lots of the forest has been cut down to make way for people. Anyone that has walked in the forests of the Pacific Northwest knows the temperature and humidity is nothing like the city. Nothing like.
Why not study the temperature differences between Sea-Tac and the surrounding forests? That would show true climate change. But of course the researchers would need to get out from behind their computers.
Why are weather stations in the Pacific Northwest not located exclusively in the rain forests? That would show if there is any UHI independent climate change happening. Why are they located almost exclusively in artificial city and airport environments?
Why are researchers looking for warming signals in the artificial environments? Why no comparison to the surrounding natural environments?
ferd berple says:
July 23, 2013 at 6:32 am
Because as anyone who has travel in the open (bicycle, motorcycle, convertible) it’s obvious when you travel past large trees outside of a city or entire a forest, the you can feel 5-10 degrees of temp change.
The authors previously noted that their study comprised 43 stations in Western WA and OR. These were from the United States Historical Climate Network (USHCN). They also added SeaTac and Portland Airport and removed high elevation stations.
They also note “The discontinuities identified by the National Climatic Data Center’s pairwise algorithm (Menne et al., 2009) in the monthly USHCN version 2 data were applied to the daily data. This ensured that the instrument change from liquid-in-glass thermometers to maximum-minimum temperature sensors (MMTS) as well as any urban heat island effect was taken into account before we calculated trends.”
http://cses.washington.edu/cig/outreach/pnwscienceconf2011/posters/Bumbaco.pdf
see also http://cses.washington.edu/cig/outreach/workshopfiles/vancouver2010/bumbaco.pdf
The actual paper is here, but behind a paywall:
http://journals.ametsoc.org/doi/abs/10.1175/JAMC-D-12-094.1
I live about 70 miles north of Seattle, on Whidbey Island. Fairly rural area. No nighttime heatwaves here. For the last few years (since 2008) we’ve barely had a summer. This is the first year since then that I’ve been able to mow my lawn without having to wear a jacket or sweatshirt. But at night it’s nice and cool, in the 50sF.
On a side note. I was back on Orcas Island a couple weeks ago. I decided to stop by the Olga, WA MMTS again to see if anything had changed since the last time in 2009. The sensor wasn’t there any more. I couldn’t locate it from the road. It’s possible that the vegetation has overgrown it, and I didn’t want to enter the property without permission.
I also can’t figure out how to find the station history and temp history any more. The USHCN site seems to have changed since the last time I was there.
““Elevated low-level moisture at night tends to trap the heat in.”
Not well stated at all. Water vapor “traps” nothing. It retards cooling by intercepting and redirecting LWIR while converting some of it to heat, but it traps nothing.
“However, people in the Midwest are acclimated to the heat while in the Northwest, they are not. People in other regions of the country may also be more likely to have air conditioning in their homes.” What a sweeping generalization, but gives a clue to how local their thinking is. I live north of Spokane, WA and summer is quite warm, almost everyone I know has AC and we are quite used to the heat.
Mostly I take exception to the ability of someone who is supposed to be a scientist and ignore UHI, or use terminology in describing weather that seems devoid of science.
Dear Mr. Bradley,
Forgive me for thinking you were mistaken about which continent the article was discussing. You ignored, however, my assertion that the author’s monsoon theory was, in THIS case, mistaken. What do you think of my theory that the humidity was overwhelmingly due to evaporation (given our local climate)? I am not disputing monsoon theory per se. I am asserting that it did not apply to any significant degree in this case.
Take care. Hope winter isn’t too cold for you down there, this year.
Your ally in the battle for Truth in Science,
Janice
To ferd berple:
You wrote:
Dr. Roger Pielke, Sr., has been banging that drum for years. His war cry is
“Land use is a first-order climate forcing!” He has been attempting to interest
other members of the climatology profession in this effect for multiple years,
but to no avail.
They’re referring to regions west of the Cascades, most likely. I live on Whidbey Island, and while I do have AC, I rarely use it. A lot of the older homes around here don’t have AC. But, I grew up in Virginia, where it gets much hotter in the summer, and much colder in the winter.
Fantastic! A new baseline. Hump Month: October, the pregnant pause between A/C and heated interiors!
Land-use is definitely a first-order climate measurement forcing. Climate forcing, maybe a second-order at most.
Sorry for the delay — this thread motivated me to reorder priorities to finish this:
http://img7.imageshack.us/img7/1659/oiio.png
That’s what’s governing (centrally limiting) Pacific Northwest North America climate.
Supplementary:
http://tallbloke.files.wordpress.com/2013/03/scd_sst_q.png
http://img845.imageshack.us/img845/6451/1xx.gif (2-slide animation)
See Marcia Wyatt’s “stadium wave” work for background clarifying why the differential equation works.