Heat Waves (4) A Climate Case Study:
Heat Waves (4) A Climate Case Study:
In the last article I wrote that the extreme events of 2011 were providing us with the opportunity to think about climate and how to cope with a warming world. The U.S. is experiencing an extreme heat event this week (Masters @ WU). This heat wave is the consequence of a strong, stationary high pressure system over the central U.S., and it will move to the east over the next few days. Back on July 14th The Capital Weather Gang did a nice write up on the forecast of the heat wave. At the end of this blog are links to my previous blogs on heat waves and human health.
When thinking about weather, climate, and extreme events an important idea is “persistence.” For example, a heat wave occurs when there are persistent high temperatures. Persistent weather patterns occur when high and low pressure systems get large and stuck; that is, they don’t move. In the Figure below, you need to imagine North America and the United States. There is a high pressure center over the proverbial Heartland. With blue arrows I have drawn the flow of air around the high pressure system, and in this case moist air. There is moisture coming from the Gulf of Mexico and, in fact on the date when this was drawn, from the Pacific. This is common in the summer to see both the Gulf of Mexico and Pacific as sources of continental moisture.
Figure 1: Schematic of a high pressure system over the central United States in July. While generic, this is drawn to represent some of the specifics of 2011. The green-shaded area is where there have been floods in 2011. The brown-shaded area represents sustained drought in the southern part of the nation.
At the center of this high pressure system there is a suppression of rain, because the air is moving downward. This sets up a situation where the surface heats from the Sun’s energy. There is not much mixing and cooling, because of the suppression of the upward motion that produces rain. Hence, if this high pressure system gets stuck, then there is persistent heat. This is a classic summer heat wave.
Let’s think about it some more. There is lot of moisture being drawn around the edge of the high pressure system, and this moisture contributes to the discomfort of people. People – just a short aside about people: if we think about heat and health, then we are concerned about people’s ability to cool themselves. It is more difficult to cool people when it is humid because sweat does not evaporate. Suppose that in addition to this moisture, there is a region where the ground is soaked with water from flooding. Then on top of already moist air coming from the Gulf, there is local evaporation into the air being warmed by the Sun. If on the interior of the high, where the rain is suppressed, there is hot, wet air, then it becomes dangerous heat.
It’s not easy to derive a number that describes dangerous heat. But in much of the eastern U.S. a number that somehow combines temperature and humidity is useful. Meteorologists often use the heat index. It’s the summer time version of “it’s 98 degrees, but it feels like 105.” For moist climates, the heat index is one version of the “it feels like” temperature. Jeff Masters tells me that in Newton, Iowa yesterday, July 17, 2011, the heat index was 126 degrees F. (see here, and 131 F in Knoxville, Iowa on July 18)
Another measure of heat and humidity is the dew point; that is, the temperature at which dew forms, and effectively limits the nighttime low. The dew points in Iowa, South Dakota, Minnesota, and Wisconsin are currently very high and setting records. Here is a map of dew point for July 19, 2011.
Figure 2: Exceptionally high dew points centered on Iowa.
Now if I was a public health official, and I was trying to understand how a warming planet might impact my life, then here is how I would think about it. First, the Gulf of Mexico and the Pacific are going to be warmer, and hence, there will be more humid air. This will mean, with regard to human health for the central U.S., heat waves will become more dangerous, without necessarily becoming hotter. It is also reasonable to expect heat waves will become more frequent and last longer, because those persistent, stuck high pressure systems are, in part, forced by the higher sea surface temperatures. If I am a public health official here is my algorithm – heat waves are already important to my life, and they are likely to get more dangerous, more frequent, and of longer duration. But by how much? Do I need to know by how much before I decide on a plan for action?
If I think about the air being more humid, then I might expect to see trends in the heat index. I might expect to see trends in dew points, and trends in the nighttime minimum temperatures getting higher. (That’s where a greenhouse effect really matters.) I worry about persistent heat, warm nights, and the inability of people and buildings to cool themselves. I worry about their being dangerous heat in places where people and emergency rooms are not used to dangerous heat – not acclimated to heat – not looking for heat-related illness.
Let’s go back to the figure. Rain is suppressed in the middle of the high pressure system, but around the edge of the high pressure system it will rain; there will be storms. (see Figure 3 at the end) The air around the edge of high is warm and very wet. Wet air is energetic air, and it is reasonable to expect local severe storms. (See Severe Storm on Lake Michigan) And if the high pressure is persistent, stuck, then days of extreme weather are possible. If this pattern sets up, then there is increased likelihood of flooding. If I am that public health official, then I am alerted to the possibility of more extreme weather and the dangers thereof. But, again, can the increase of extreme weather be quantified? Do I need to quantify it before I decide on a plan of action?
Still with the figure - what about that region of extended drought and the heat from the high pressure system? Dehydration becomes a more important issue. As a public health official, I start to see the relation of the heat event to other aspects of the weather, the climate. I see the relation to drought. I see the flood, and it’s relation to the winter snow pack and spring rains.
So what I have presented here is to look at the local mechanisms of the weather – what are the basic underlying physics responsible for hot and cold, wet and dry – for moist air? If I stick to these basic physics, and let the climate model frame the more complex regional and global picture, what can I say about the future? Do I have to have a formal prediction to take action? Here in 2011, I see drought and flood and hot weather and warm oceans that interact together to make a period of sustained, dangerous heat. It does not have to “set a record” to convey the reality of the warming earth. It tells me the type of event that is likely to come more often, of longer duration, and of, perhaps, of greater intensity. If I am a public health planner, then I can know this with some certainty. The question becomes, how do I use that information in my planning?
r
Figure 3: Radar loop showing precipitation around the edge of the large high pressure system in the middle of the continent. July 19, 2011.
Previous Blogs on Heat Waves
Hot in Denver: Heat Waves (1)
Heat Waves (2): Heat and Humans
Heat Waves (3): Role of Global Warming
Reader Comments
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You're right. It was just a flirtation.
--No nations have hit all-time record lows since at least 2009.
--United States record high and high minimum temperatures have outnumbered record lows and low minimums this year by better than 2-to-1 (33,650 to 16,672). New high maximum records have outnumbered new low minimum records by 10,556 to 4,299, or 2.45-to-1.
--Many areas of the nation just ended their hottest July ever. From the Midwest to the Atlantic Seaboard, it has been nothing but heat. Record highs of all types outnumbered record lows by 8,744 to 1,195, a ratio of 7.3-to-1.
--It's also been nothing but wet, either; several locations--including Chicago--saw all-time record high one-day rainfalls.
--Record high heat indices were set all across the nation, with numerous locations setting all-time record highs in that regard.
--It's not just the US, of course; Korea just last week saw the heaviest rainfalls in its history. So did the Philippines. So did Japan. So did Brazil. So did Australia.
And this, of course, comes on the heels of remarkable tornado records, flood records, snowfall records, drought records, and on and on and on and on. And all this in what was supposed to be a "cool" year. (And if you think this is something, wait until next year.)
This all begs the question: just what is it that people aren't seeing? And more to the point: is it simply ideology that's preventing them from seeing it?
Never before seen huge wind storms on Saturn's south pole.
Never before seen asteroids in Earth's blindspots.
Is it simply idealogy that prevents us from excepting the randomness of nature?
You try so hard, and I give you props for that, but in your haste to disprove me, you've again failed. sigh...
Chicago had the wettest day in its 130-year record. Period. My sources are the NCDC. I know it's a government organization and as such is suspect to most CWMs, but it's a real record regardless.
Parts of Australia have seen by far their rainiest single-day, single-month, and single-season rainfalls ever. Period. My sources are again government organizations and as such are alsosuspect to most CWMs, but they are real records regardless.
The fact is, extreme weather has been happening around the globe with increasing frequency and severity, just as AGWT predicted it would. And, Roy Spencer wishful thinking notwithstanding, it's only going to get worse. Much worse.
I do appreciate your spending so much time double-checking me; I'm sure you'll find as folks always do that I am as accurate and precise as possible.
I suppose one could look at everything that's been happening and say, "I'm sure it's all just random." But that's a very unscientific approach. When the random and the extreme become commonplace and unavoidable, they're no longer random and extreme: they're the new normal.
I predict, sometime between now and the end of time in the universe, that it will snow in Miami again.
I predict, sometime between now and the end of time in the universe, the Great Lakes will freeze completely.
I predict, sometime between now and the end of time in the universe, the oceans on Earth will boil.
Didn't happen. Is larger than average, but not close to record.
Oxygen levels:
In this article: http://www.nola.com/environment/index.ssf/2011/08 /dead_zone_larger_than_average.html
And they say:
"The major disruptor of the size was Tropical Storm Don that followed the Research Vessel Pelican across the Gulf of Mexico towards Texas and whipped up the winds and waves," Rabalais said in a news release issued overnight.
?
Umm, no, there were no special wind or wave conditions along the LA coast from Don (much less any clouds, for that matter). Tiny little system that just about didn't happen.
So any ideas as to why it really didn't meet the expectations?
Why? Maybe you should just read your own links.
At the size of Connecticut, it's still a significant fish-choking event. This type of event impacts the lives of many fishermen and shrimpers. Hardly something to make light about.
Coastal Ocean Dead Zones Increasing at Exponential Rate Worldwide
Neapol's statement is in agreement with the a growing body of scientific literature. In this case we have models that underestimate the changes in extreme precipitation events.
Here is one example of a recent paper dealing with this issue:
Human contribution to more-intense precipitation extremes. Seung-Ki Min, et al. Nature 470, 378–381 (17 February 2011)
The alarming (always), well-publicized prognostication didn't happen. Again. Like usual.
(Aside: I'm all for less pollutants and no dead zone. But I'm more for lower food prices and less hungry people, globally.)
Too much rain- man's fault
There is no debate. This is a kindergarten argument of repitition..
"why?
"because.
"why?
"because.
"why?
"because.
"why?
"because."
By virtue of metastasis, every event of any sort is now climate change related.
Just look at the headlines, blogs put forth, and the posts from the ideologues on this site and particular blog.
Most ever !
In recorded history !
In the last 1,000 years !
How many times do you hear "Unprecedented" by some and a 30 year record of events under the statement?
I really enjoyed the "worst in 1,000 years" statement with respect to the Russian heat wave which was admittedly caused by a natural blocking pattern.
The embellishment is obvious and ongoing.
You simply can't cover credibility and publicity problems by connecting weather dots with a climate change pen. It's not working.
Hence, the failure of Kyoto is all the evidence you need.
any study that refutes "predictions" of one side of the argument causes an atmosphere like what you would see on the floor of Congress or Parliment.
To me personally, that is more along the lines of parlimentary procedure...which leads to the great stall in real progress and understanding.
not the Green Understanding
does science really need advertising to be accepted?
when there is one sigular sample (the Earth) and one sigular hypothesis (is man the climate changer?), can you call the experiment accurate? And is 30 years of testing the hypothesis enough to prove its validity?
Kindergarten? You seem a bit lost. Let me give you a hand. To replace your "because's", just read the primary literature or look for reputable sources of information for laypeople. There is lot's of scientific information out there to fill in the areas where you lack knowledge. Science Daily is a great place to start to fill in your because's.
For an answer to your questions about why more precipitation and droughts, look up some information on what sets up climate zones on the planet. Global circulation zones are not random. Neither are things like rain shadows caused by mountain ranges. From there you can jump into the IPCC report which reviews this topic in detail.
I hear that!
All over 1.4 highly questionable degrees across 160 years. But it is the rapid nature of the rise, but it stopped for a decade? Yep, its fossel fuels fault the temp stopped, but now it is faster than ever due to scrubbers on the coal plants in China, no matter if they are opening up more than one a week?
Yea right, ya think!
Why do you implicate Jeff Master's in your conspiracy theory? He is always cautious when making attributions for single events. As are the overwhelming majority of climate scientists. If the popular press is often poor at it, that is not a reflection on what the science can say with a high degree of certainty.
Thanks. I'll check that out after we play climate duck-duck-goose and ground temperature hide-and-seek.
For the second time: I never said anything about a 24-hour rainfall record, so I'm not sure why you insist on focusing on that. I wrote, "It's also been nothing but wet, either; several locations--including Chicago--saw all-time record high one-day rainfalls." I've proven it right; if you can prove it wrong, go ahead and try.
Now, is this a matter of being blinded by ideology? I think perhaps it is. At any rate, constant attempts at "pwning" grow tiresome--especially when they're fruitless.
No. There was an all-time record low in Oklahoma.
Only a true denialist would look at a "worst in 1,000 years" heat wave and say, "It's just part of a natural blocking pattern".
Right. ;-)
I'm not sure what you've beeen reading, but the only records breaking a 30-year set are the Arctic Sea ice satellite measurements. Multiple temperature and precipitation records that have stood since the late 1800s--that is, when official recprdkeeping began in many areas--have been shattered in the last few years.
A person would have to be ideologically blind to not see how quickly things are changing...
Anyone of the opinion that a degree-and-a-half rise in global temps is petty probably needs to go back to Climate Basics 101.
Link
You must be smarter than NOAA :)
Natural Variability Main Culprit of Deadly Russian Heat Wave That Killed Thousands
NOAA March 9, 2011
What institution did you study Climate Basics 101 at?
the asterik.
* since record keeping began in 1979
When it comes to weather, the random and extreme are commonplace and unavoidable. It always has been. That's the nature of weather. Using a localized weather event, such as a calendar day rainfall record for Chicago, in trying to prove a human component to the global climate is sophomoric.
There isn't one shred of evidence that today's weather is any more extreme than any other period on record in question in any other region of the world. There simply isn't. In other words, there are hundreds of examples of extreme weather of varying nature for various places at various stable lengths of time that can be compared against each other.
Senator Inhofe reads this site? Well, all I can say is "Keep up the good work!".
..maybe google his committee Chairmanships as well.
Climate Change Update
Senate Floor Statement by
U.S. Sen. James M. Inhofe(R-Okla)
January 4, 2005
These findings come alongside a spate of new reports that, at least in the eyes of the media, supposedly confirm the "consensus" on global warming. "The Arctic Climate Impact Assessment," released last fall, perfectly fits that mold. "Arctic Perils Seen in Warming," blared a headline in the New York Times. As the Times wrote, "The findings support the broad but politically controversial scientific consensus that global warming is caused mainly by rising atmospheric concentrations of heat-trapping greenhouse gases, and that the Arctic is the first region to feel its effects."
What do we really know about temperatures in the Arctic? Let's take a closer look. As Oregon State University climatologist George Taylor has shown, Arctic temperatures are actually slightly cooler today than they were in the 1930s. [Chart #1] As Dr. Taylor has explained, it's all relative-in other words, it depends on the specific time period chosen in making temperature comparisons. "The [Arctic Climate Impact Assessment]," Dr. Taylor wrote, "appears to be guilty of selective use of data. Many of the trends described in the document begin in the 1960s or 1970s-cool decades in much of the world-and end in the warmer 1990s or early 2000s. So, for example, temperatures have warmed in the last 40 years, and the implication, 'if present trends continue,' is that massive warming will occur in the next century."
The esteemed Sen. on Video and record..
I had no illusion that you would and expected you to remain in your sandbox. But, perhaps some others will not be bamboozled by your misleading and clearly uninformed comments.
Mostly questions. :)
Why would the phytoplankton bloom that dies and creates the dead zone be lower than expected?
Could the quantities of COREXIT used to disperse the oil spill have a play here?
Did any unusual eddies that spin off the Gulf Stream loop somehow disperse phytoplankton or dilute fresh water in any unusual way?
Have the severe rains and floodings upstream prevented or delayed the normal applications of fertilizers (no reason to fertilize a flooded yard or field) or diluted them?
Does ocean acidification affect the phytoplankton bloom or create an enviroment for viruses that may affect their growth as seen in coral bleaching now championed to be caused by acidification alone? As Coral reef restoration projects have been overwhelmingly successful(much to the dismay and posturing of GW and acidification alarmists). It is what it is.
Or did they just get it all wrong? Considering the sloppy performance of their climate models, that would not surprise me in the least.
I'll go with the last one...they just do sloppy work with blinders on. Tsch tsch...
I agree that it is very hard to tie one event to AGW. And there is one paper I know that attempts to do so. But, looking at long-term trends over various spatial scales, "not one shred". Really.
http://idn.ceos.org/climdiag/Metadata.do?Portal=c limatediagnostics&KeywordPath=[Data_Center%3A+Shor t_Name%3D%27USGCRP%27]&NumericId=33565&MetadataVie w=Text&MetadataType=0&lbnode=mdlb2
http://www.sciencedirect.com/science/article/pii/ S0012821X10006072
http://www.sciencemag.org/content/328/5986/1642.s hort
https://bora.uib.no/handle/1956/1477
http://www.springerlink.com/content/9734gl1774750 362/
From post above: Human contribution to more-intense precipitation extremes. Seung-Ki Min, et al. Nature 470, 378–381 (17 February 2011)
Don't have time to post links to the dozens of other papers done at regional and global scale.
So let me get this right.
The first referenced addresses, not links, are not functional.
The next talks about Dry times ahead due to climate change and the next talks about excess precipitation due to climate change.
Everything is a climate change problem?
You are correct, just not for the reasons you think.
Here, try one small piece of the puzzle that does not contradict itself.
Land use/land cover changes and climate: Modeling
analysis and
observational evidence
Here,,,,,,,,, slice this one to pieces folks.
C'mon, you can do it?
I know it is really broken up now.
I believe ole Hugh said it all there, I do have one question on one of his statements. In your above statement you said that you believe that there is better ways to spend money for disaster prevention. Please explain. I believe that Pat has pointed out several promising facts on how his " Tunnels " can prevent disaster including death and monitary and enviromental damage to the Gulf coast then hopefully someone will take this to the next level. Ive seen the model video and the schematic of his and he proves 100% that this is a natural energy source. To comment on another statement listed above on possibly decreasing hurricanes from a catagory 5 to a catagory 3, if there is any doubt that this can possibly work then investors and meteoroligists from around the world need to be looking into this. We waste billion's and billion's of dollars in foreign aid that we don't have, beings our deficit is in the Trillions and operating cash balance only being 73.8 billion. Hell why not, a few billion more wont hurt to invest into somthing that could possibly turn that number into a positive and save our oil reserve. Just my thoughts.
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