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
Can’t believe no one has mentioned that airport temp. is taken near the runways because it is a critical safety factor for aircraft take-offs. When it is hot, there may not be enough runway length to get safely airborne or stop when there is an engine “loss” at a critical part of the take-off roll.
Using airport temps. for climate is criminally stupid.
Land use in the Willamette Valley has changed from farming to lots of subdivisions over the last 50 years. Same can be said for the SEA-TAC area, huge population growth. Land use was farm and forest up to early sixtys.
Third runway was built during the 2000’s, completed in 2008. all roads west of runway two are new simnce then.
Southwest humidity transported northward sounds a plausible mechanism for night time heat waves, but they needed to include humidity data to support or not this hypothesis.
In this work, 45 years (1961–2005) of hourly meteorological data in Taiwan, including temperature, humidity, and precipitation, have been analyzed with emphasis on their diurnal asymmetries. A long-term decreasing trend for relative humidity (RH) is found, and the trend is significantly greater in the nighttime than in the daytime, apparently resulting from a greater warming at night. The warming at night in three large urban centers is large enough to impact the average temperature trend in Taiwan significantly between 1910 and 2005. There is a decrease in the diurnal temperature range (DTR) that is largest in major urban areas, and it becomes smaller but does not disappear in smaller cities and offshore islands. The nighttime reduction in RH is likely the main cause of a significant reduction of fog events over Taiwan. The smaller but consistent reductions in DTR and RH in the three off-coast islands suggests that, in addition to local land use changes, a regional-scale process such as the indirect effect of anthropogenic aerosols may also contribute to these trends.
http://journals.ametsoc.org/doi/abs/10.1175/2009JCLI2514.1
UHI looks the likeliest reason.
http://onlinelibrary.wiley.com/doi/10.1002/jgrd.50243/full
Annual mean diurnal temperature range (DTR) for surface air over land decreased during the period 1950–2004 by 0.07°C per decade due to a greater rate of increase in daily minimum temperatures (0.20°C per decade) compared to daily maximum temperatures (0.14°C per decade) [Vose et al., 2005; Trenberth et al., 2007]. Detrended variations in global DTR are weakly correlated with detrended variations in global mean temperature [Braganza et al., 2004]. The forcings and feedbacks responsible for the trend in DTR may, therefore, differ from those for global mean temperature. Indeed, simulated trends in surface shortwave (SW) radiation, surface downwelling longwave (LW) radiation, and DTR for surface air over land for the period 1950–1999 [Zhou et al., 2010] showed changes in DTR were correlated with the changes in net SW radiation while changes in LW radiation were correlated with the warming of annual mean temperature.
Feedbacks associated with a CO2-induced warmer, wetter climate have been identified as more influential in reducing DTR [e.g., Stenchikov and Robuck, 1995]. The impact of water vapor feedback on DTR, with enhanced near-infrared absorption of solar radiation in the atmosphere, was found to be approximately seven times stronger than the reduction in DTR caused by CO2 alone [Cao et al., 1992; Watterson, 1997]. The observed reduction in DTR in synoptic weather reports during the period 1980–1991 over a wide land area was linked to observed increases in daytime cloud cover that reduced maximum temperatures [Dai et al., 1999]. Stone and Weaver [2003] found that, in addition to the influence of the radiative effects of clouds on maximum temperatures, the heat capacity of soil, which is very sensitive to moisture content, exerts a controlling influence on minimum temperatures. Surface shortwave radiation is sensitive to changes in cloud cover and aerosol concentrations, factors that have also been linked to trends in surface air DTR. Dimming and subsequent brightening of surface shortwave radiation has been correlated with global trends in surface air DTR [Wild et al., 2007]. These studies point to complex causes of surface air DTR trends driven by diurnal variations in multiple forcings and associated feedback.
so, yeah, increased water vapor, decreased shortwave, increased longwave, a simple function of AGW induced feedbacks, according to standard model predictions. . . so what else is new???
@jai, like I told BillD, the data shows no loss of nightly cooling.
When you look closely at individual stations, the increase in night “heat waves” coincides very well with NOAA switching to MMTS temperature sensors during the late 1980s and early 1990s.
@John West
I saw a stuffed Bengal tiger in the Melbourne museum. It was so life-like, I was nervous the whole time I was in the building, especially when it was out of sight!
UHI, including the effect of reduced urban aerosols, looks the likeliest reason.
Night time warming is more than day time warning and this is happening just about every where, not just in developed areas. When we see night time warming in the Mountains, deserts, forest and arctic, this is likely to be due to green house gases, not a urban heating effect.
@BillD, follow the link in the first post, and explain how greenhouse gases warm the planet, when there’s zero trace of a loss of nightly cooling in the temp record.
Fascinating. Does April show a similar cooling trend?
And are the months with the hottest trends January and July?
I’m wondering how they found a clear enough day to take that image…
Gerry
I grew up with a view of the runways at Sea-Tac. When I was a kid, in the early 1960’s, the airport had a rather conventional “crosswind” layout with one N/S, and one E/W which crossed the S end of the N/S runway, approximately where the 2nd runway ends. It may even be the taxiway visible in the photo above. There were 2 more runways run at diagonals which crossed each other just W of the N/S runway near the center of the field, directly in front of the terminal. In the 1960s, the N/S runway was extended S past 188th and by 1970, was extended again and joined by the 2nd N/S runway. At that time the non N/S runways were torn up and portions were converted to taxiways. The asphalt next to the weather station is a taxiway that was added for the 3rd runway in the 2004-2008 timeframe.
The 3rd runway was opened in 2008. The airport bought out an entire neighborhood, built a retaining wall 70-130 feet high in places, and dumped 16 million yards of dirt in order to bring the surface up to grade. The wall begins at the freeway exit on the W side of the airport, and wraps around the N end of the field. Just hauling in the dirt took a fleet of trucks 4 years.
When the weather station was installed, that point was well away from the runways and the terminals, on grass and relatively isolated on the edge of the hill. Now it’s next to a taxiway, with jet turbines washing over it continually. Sea-Tac handles almost 1000 flights per day.
More hot air from the hot air factory. I live about an hour due north of Seattle. I was here all of June through today. While we did have a few days around the end of June where our usual evening onshore flow (Westerlies) failed us and it was disgustingly like Virginia (humid and hot), it was in NO WAY a “heat wave.” Not even for one night. The End.
Just another LOAD OF BALONEY to keep the Envirostalinist controllers in businesses.
“UNDER COVER OF DARKNESS” [preview of next doomsday movie]
Liar of the Day: Oooo, yes, boys and girls, the heat waves happen at night! So that’s how we know…..???
The Gullibles: ……. uuuh……… Oh, yeah!! Thaaaat’s how the heat gets into the OCEANs. It’s sneakin’ in there during the middle of the night. Mm, hm!
LOTD: [greasy smile]
*********************************
On the other hand….. I heard (via the WUWT gossip on a thread awhile back) that Mr. Jai Mitchell runs a little business in Seattle. Perhaps, the heat down there WAS horrendous. SOMETHING is affecting that poor man!
BillD says:
Do you have data to backup your comment, if so please provide it so we can all be enlightened.
“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.
===
well yeah…..average nightime temps for Portland are from 30’s to 50’s
what’s a night time “heat wave”?….55F?
And regarding the above article’s authors’ “monsoon” theory for the source of the humidity — I think that’s ridiculous. We had a LOT of rain in March and April and May and…. well, most of the year! When it started to warm up, all the water in the mountains, hills, and valleys EVAPORATED. We have such beautiful cumulous clouds around here. It looks like a story book. The humidity rose this June/July only because of the lack of our usual light winds for a few days. Then, things freshened up and, now, it’s great again!
****************
I second Wy Guy, Mr. D.
BillD says:
July 22, 2013 at 5:08 pm
Night time warming is more than day time warning and this is happening just about every where, not just in developed areas. When we see night time warming in the Mountains, deserts, forest and arctic, this is likely to be due to green house gases, not a urban heating effect.
====
and yet….when you average them in
….temperatures are still falling
Good one, Latitude (at 6:13PM)! LOL.
And, BTW, Portland, being much farther inland, is MUCH warmer on average than the greater Seattle area. Anywhere east of the Cascade Mountains, is MUCH warmer than most of the area west of the Cascades (but not as warm as that crazy mal-functioning temp. gauge in Kettle Falls (?) said it was about 4 weeks ago!).
Reminds me of the Helsinki, Finland ruse. “Oh, my! Loook hoooow HOT it is in Helsinki!!” (hence the now annual place for Seth Borenstein and his lot to gather each year). “How could it be THAT hot in FINLAND?!!” Portland = Helsinki (by analogy, I mean).
MiCro,
How in the world did you even figure out what Jai was trying to say?
With admiration for your genius,
Janice
Janice, it was by the smell.
Think of a jet engine as a giant hair drier. Some jets have two giant hair driers on the tail, and some have four giant hair driers on their wings.
Now imagine a rural weather station with nothing around it but a bunch of bored-looking cows. Occasionally they produce hot gas, but not much. Then, around 1970, you suddenly have these huge ladies running around the weather station all day and all night with giant hair driers. Could anyone ignore the obvious change in the situation surrounding the stations thermometer and effecting the environment the thermometer records?
Yes indeed, as amazing as it sounds, some people can. They ignore because they are payed for ignorance. They believe ignorance is bliss, because they get to ruffle lots of dollar bills and throw them in the air like confetti and yowl, “Whoopie!”
However, in the end, ignorance isn’t bliss. Ignorance means you are ignorant. It means you don’t know and haven’t a clue. Often, by the time you wake up and look around, and face what reality has to show you, it is too late. Serious damage has been done, not only to others (who ignorant people don’t always care a hoot about,) but also to the self, (which ignorant people, being selfish, do care deeply about.)
In fact the phrase “ignorance is bliss” comes from the next to last line of Thomas Gray’s, “Ode on a Distant Prospect of Eaton College,” written nearly 250 years ago. The ignorance it refers to is that of a young student just entering college, who knows he is ignorant but is eager to learn, and who is full of hope about the wonderful things learning may enable him to achieve. In other words, the reason ignorance is bliss is because the blissful student believes ignorance is about to end.
It is quite a different thing to perpetuate ignorance, (blandly and stupidly if it is only because it is “politically correct,” or willfully and deviously if it is “for the money.”) In essence such willful ignorance is to give up on Truth. One is surrendering hope in a better future, (even if one says “we are saving the earth,”) and curses the prospects our children face, (even if one says “it is for the children.”)
At some point or another even the most evasive of us have to decide whether we are on the side of Truth or the side of ignorance. The consequences are as different as day and night. Therefore I’d advise all to not “ignore,” especially not to ignore huge hair driers around thermometers collecting temperature records.
A description of one runway is in a 1947 crash report. Number of runways not mentioned, but hints elsewhere of intersecting runways at 45 degrees.
http://aviation-safety.net/database/record.php?id=19471130-0
Here’s an aerial view of the terminal on 1949 opening day, but no clear photo of the runway.
http://content.lib.washington.edu/cdm4/item_viewer.php?CISOROOT=/imlsmohai&CISOPTR=6520&CISOBOX=1&REC=6
Map of runways in 1956:
http://www.flickr.com/photos/12530375@N08/8038012911/sizes/l
As other have noted, the westmost of the triple runways was built 2000-2008.
Janice Moore says:
July 22, 2013 at 6:16 pm
And regarding the above article’s authors’ “monsoon” theory for the source of the humidity — I think that’s ridiculous.
I’m afraid you are wrong. We get the outer limits of the monsoon here in Perth when temperatures rise by perhaps 5C in the daytime and 7C or 8C at night. No only do we not get rain, we have horizon to horizon blue skies.
The reason is, monsoon humidity is transported close to the ground and takes perhaps a couple of months to accumulate in a location to the point precipitation occurs. That never happens here, and will never happen in the Pacific northwest.
lol, I live in downtown Portland and am still sleeping under a blanket at night.
Pure statistic shineola.
Reblogged this on Sunrise's Swansong and commented:
This is a reblog of a Watts Up With That post about a study that finds airports are warmer in the pacific Northwest than they used to be.
I am a poet and not a scientist, and there are times I should be quiet, because I got bad grades in Math. However when I glanced over the study I couldn’t see any sign they recognized the fact, (not all that scientific, and indeed something even a History major could notice,) that in the old days airports were full of prop-driven planes, which were replaced by jet-engine driven planes. As jets produce more heat, it seemed obvious they should mention this little fact, while discussing why airports got hotter.
Therefore I didn’t keep my big mouth shut, and wrote the following comment. I’m sort of proud of the way I snuck poetry into a scientific discussion:
” Think of a jet engine as a giant hair drier. Some jets have two giant hair driers on the tail, and some have four giant hair driers on their wings.
Now imagine a rural weather station with nothing around it but a bunch of bored-looking cows. Occasionally they produce hot gas, but not much. Then, around 1970, you suddenly have these huge ladies running around the weather station all day and all night with giant hair driers. Could anyone ignore the obvious change in the situation surrounding the stations thermometer and effecting the environment the thermometer records?
Yes indeed, as amazing as it sounds, some people can. They ignore because they are payed for ignorance. They believe ignorance is bliss, because they get to ruffle lots of dollar bills and throw them in the air like confetti and yowl, “Whoopie!”
However, in the end, ignorance isn’t bliss. Ignorance means you are ignorant. It means you don’t know and haven’t a clue. Often, by the time you wake up and look around, and face what reality has to show you, it is too late. Serious damage has been done, not only to others (who ignorant people don’t always care a hoot about,) but also to the self, (which ignorant people, being selfish, do care deeply about.)
In fact the phrase “ignorance is bliss” comes from the next to last line of Thomas Gray’s, “Ode on a Distant Prospect of Eaton College,” written nearly 250 years ago. The ignorance it refers to is that of a young student just entering college, who knows he is ignorant but is eager to learn, and who is full of hope about the wonderful things learning may enable him to achieve. In other words, the reason ignorance is bliss is because the blissful student believes ignorance is about to end.
It is quite a different thing to perpetuate ignorance, (blandly and stupidly if it is only because it is “politically correct,” or willfully and deviously if it is “for the money.”) In essence such willful ignorance is to give up on Truth. One is surrendering hope in a better future, (even if one says “we are saving the earth,”) and curses the prospects our children face, (even if one says “it is for the children.”)
At some point or another even the most evasive of us have to decide whether we are on the side of Truth or the side of ignorance. The consequences are as different as day and night. Therefore I’d advise all to not “ignore,” especially not to ignore huge hair driers around thermometers collecting temperature records.”
A look at Wikipedia’s history of SeaTac (http://en.wikipedia.org/wiki/Seattle%E2%80%93Tacoma_International_Airport#History) shows that it has been continually expanded since it was constructed in 1944, that is any local heat island effect has been increasing continually over time.
I’ve worked with dozens of Structural Engineers and Construction Managers from OSU. What I’ve seen being published by the OSU Church of Climatology (lol, Climatology passed spell check!) is nothing short of disgraceful.