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?
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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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More warmist slippery language. Just exactly what is "recorded history"? The last 30 years? Give me a break.
I've done so many times. I bookmark all relevant links from all members for ready access and reference, and assume others do the same.
Thanks for posting this most excellent example of denialism. Both the graph and the text talk of the number fires, yet neither talks about the extent of them, which--as any honest person knows--is much more relevant for purposes of comparison. Does that writer even know about, say, the record-obliterating 3,327,000 acres (5,200 square miles) that have burnt in Texas alone this fire season (11/10/2010 through now)?
As of Wednesday, Canada had seen 2,622 fires in 2011, which is--oh no!--only 58% of the 10-year average. But more telling: so far 2,117,593 square kilometers have burnt, 169% of that same 10-year average. Only someone simple or dishonest would focus on that former number while ignoring the more important latter.
Again, thanks.
Ok, so share the source of the information you posted in 549. It's not hard to do.
Eckington Pl, NE, Washington, District of Columbia (PWS)
Updated: 1 min 0 sec ago
Overcast
93.3 °F
Overcast
Excessive Heat Warning
Statement as of 7:47 PM EDT on July 22, 2011
... Excessive heat warning remains in effect until 10 PM EDT this
evening...
... Excessive heat warning remains in effect from 10 am to 8 PM
EDT Saturday...
* temperature... high temperatures Saturday around 100.
* Heat index values... up to 112.
Precautionary/preparedness actions...
An excessive heat warning means that a prolonged period of
dangerously hot temperatures will occur. The combination of hot
temperatures and high humidity will create a dangerous situation
in which heat illnesses are likely. Drink plenty of water... stay
in an air-conditioned room... stay out of the sun... and check on
relatives and neighbors.
Take extra precautions if you work or spend time outside. When
possible... reschedule strenuous activities to early morning or
evening. Know the signs and symptoms of heat exhaustion and heat
stroke. Wear lightweight and loose-fitting clothing.
To reduce risk during outdoor work... the occupational safety and
health administration recommends scheduling frequent rest breaks
in shaded or air-conditioned environments. Anyone overcome by
heat should be moved to a cool and shaded location. Heat stroke
is an emergency - call 9 1 1.
Air Quality Alert
Statement as of 4:28 PM EDT on July 22, 2011
... Air quality alert is in effect for Saturday July 23 2011...
The metropolitan Washington Council of governments in association
with Maryland department of the environment, Virginia department
of environmental quality, and district department of environment has
issued a code red air quality alert Saturday for the DC Metro area.
A code red air quality alert means that air pollution concentrations
within the region are unhealthful for the general population. The
effects of air pollution can be minimized by avoiding strenuous
activity or exercise outdoors.
For more information on ground-level ozone and fine particles...
visit www.Cleanairpartners.Net.
425 PM EDT Thu Jul 21 2011
... Air quality alert is in effect for Friday July 22 2011...
The metropolitan Washington Council of governments in association
with Maryland department of the environment, Virginia department
of environmental quality, and district department of environment has
issued a code red air quality alert Friday for the DC Metro area.
A code red air quality alert means that air pollution concentrations
within the region are unhealthful for the general population. The
effects of air pollution can be minimized by avoiding strenuous
activity or exercise outdoors.
For more information on ground-level ozone and fine particles...
visit www.Cleanairpartners.Net.
Record Report
Statement as of 05:30 PM EDT on July 22, 2011
... Record all time maximum temperature has been set at Washington
Dulles Airport Virginia...
A new record all time maximum temperature has been set at Washington
Dulles Airport of 105 degrees f at 352 PM EDT this Friday afternoon.
This breaks the old all time record Max of 104f set twice... on July
16 1988 and again on August 20 1983.
Official temperature records began on November 17 1962 at Dulles
Airport in northern Virginia.
Public Information Statement
Statement as of 6:48 PM EDT on July 22, 2011
public information statement
National Weather Service Baltimore MD/Washington DC
646 PM EDT Fri July 22 2011
... Maximum temperature and heat index...
The following list shows preliminary maximum temperatures and heat
indices so far for several locations on Friday July 22 2011 up
through 6 PM EDT...
Max Max
city temp f heat index f
Baltimore MD Inner Harbor... dmh 108 124
Washington DC Reagan natl... dca 102 121
Annapolis MD... ... ... ... ... .nak 101 119
Baltimore MD BWI Airport... .BWI 106r 118
Dulles VA Airport... ... ... ..iad 105r 117
Charlottesville VA... ... ... .cho 102 112
Martinsburg WV... ... ... ... ..mrb 103 111
Hagerstown MD... ... ... ... ... hgr 100 110
Baltimore MD-BWI broke a daily record high for the date.
Dulles Airport VA-broke its all time high temperature record... its
temperature records go back to Nov 1962.
Note... the NWS does not keep heat index records.
So NOAA and NSIDC are warmist. LOL!
Agreed.
Intermission?
Is man's interference of stopping fires prematurely contributing to changes in climate and ecosystems?
An equal question would be what about the ones he starts?
NOAA study: Increase in particles high in Earth’s atmosphere has offset some recent climate warming
July 21, 2011
A recent increase in the abundance of particles high in the atmosphere has offset about a third of the current climate warming influence of carbon dioxide (CO2) change during the past decade, according to a new study led by NOAA and published today in the online edition of Science.
In the stratosphere, miles above Earth’s surface, small, airborne particles reflect sunlight back into space, which leads to a cooling influence at the ground. These particles are also called “aerosols," and the new paper explores their recent climate effects -- the reasons behind their increase remain the subject of ongoing research.
“Since the year 2000, stratospheric aerosols have caused a slower rate of climate warming than we would have seen without them,” says John Daniel, a physicist at the NOAA Earth System Research Laboratory (ESRL) in Boulder, Colo. and an author of the new study.
The new study focused on the most recent decade, when the amount of aerosol in the stratosphere has been in something of a “background” state, lacking sharp upward spikes from very large volcanic eruptions. The authors analyzed measurements from several independent sources – satellites and several types of ground instruments – and found a definitive increase in stratospheric aerosol since 2000.
“Stratospheric aerosol increased surprisingly rapidly in that time, almost doubling during the decade,” Daniel said. “The increase in aerosols since 2000 implies a cooling effect of about 0.1 watts per square meter – enough to offset some of the 0.28 watts per square meter warmingeffect from the carbon dioxide increase during that same period.”
The reasons for the 10-year increase in stratospheric aerosols are not fully understood and are the subject of ongoing research, says coauthor Ryan Neely, with the University of Colorado and the Cooperative Institute for Research in Environmental Sciences (CIRES). Likely suspects are natural sources – smaller volcanic eruptions – and/or human activities, which could have emitted the sulfur-containing gases, such as sulfur dioxide, that react in the atmosphere to form reflective aerosol particles.
Daniel and colleagues with NOAA, CIRES, the University of Colorado, NASA, and the University of Paris used a climate model to explore how changes in the stratosphere’s aerosol content could affect global climate change – both in the last decade, and projected into the future. The team concluded that models miss an important cooling factor if they don’t account for the influence of stratospheric aerosol, or don’t include recent changes in stratospheric aerosol levels.
Moreover, future global temperatures will depend on stratospheric aerosol. The warming from greenhouse gases and aerosols calculated for the coming decade can vary by almost a factor of two — depending on whether aerosols continue to increase at the same rate as over the past decade, or if instead they decrease to very low levels, such as those experienced in 1960.
If stratospheric aerosol levels continue to increase, temperatures will not rise as quickly as they would otherwise, said Ellsworth Dutton, also with NOAA ESRL and a co-author on the paper. Conversely, if stratospheric aerosol levels decrease, temperatures would increase faster. Dutton and his colleagues use the term “persistently variable” to describe how the background levels of aerosol in Earth’s stratosphere can change from one decade to the next, even in the absence of major volcanic activity.
Lidar instruments - pointing up from the ground or down from satellites - use reflected light to measure the amounts of particles and their locations, which can influence climate.
Lidar instruments - pointing up from the ground or down from satellites - use reflected light to measure the amounts of particles and their locations, which can influence climate.
Download here. (Credit: CIRES/NOAA)
Ultimately, by incorporating the ups and downs of stratospheric aerosols, climate models will be able to give not only better estimates of future climate change, but also better explanations of past climate changes.
“The ‘background’ stratospheric aerosols are more of a player than we thought,” said Daniel. “The last decade has shown us that it doesn’t take an extremely large volcanic eruption for these aerosols to be important to climate.”
Authors of the paper are: Susan Solomon, University of Colorado; John Daniel, Chemical Sciences Division of NOAA’s Earth System Research Laboratory; Ryan Neely, CIRES-University of Colorado and NOAA-ESRL; J.P. Vernier, NASA-Langley Research Center and University of Paris; Ellsworth Dutton, Global Monitoring Division of NOAA-ESRL; and Larry Thomason, NASA-Langley.
Link
we can tough it out for a few years, just kick it in the shade
might be nice
Their position is an emotional one, which can be summarized as
"I don't like it, so I'm not having it"
You can't argue with that mentality, because argument is rational and their emotional response is irrational.
Are they still saying the world hasn't warmed since 1998?
Nice scientific response, Muller. ;-)
To help clarify the issue for you, let's try a little reductio ad absurdum, shall we? Now, suppose there were a million fires that burnt a quarter acre each one summer. The following year, there was only one fire, but it consumed a hundred million acres. Now, would it still be your contention--and that of the halfwit who wrote the breathless article to which you linked--that the latter wasn't as bad as the former?
(BTW: George Soros is a great man, a far-reaching philanthropist, and a wildly successful capitalist. Therefore, I appreciate the comparison. Thank you.)
Nice article about mentality and factual belief.
Also this one.
So I ask myself: am I part of this? Do i instinctively hate what I see as the hate and corruption of the new GOP, Tea Party and denialist rhetoric so much that I can't even read a denialist article without apriori dimssing it?
I don't think I do that.... but who knows, maybe I do. So i offer up my choice again: fix the problem, real or not. If not real, we are free of oil and the discussion is moot. If real, we have saved the world.
I simply don't understand why anyone would want to be right so much that they are willing to risk the world for nothing.
More storms more lightening.
How we keep it there and away from here?
It's beyond the scope of this forum, obviously, but a side-by-side comparison of their respective philanthropic ventures may shed some light on the subject.
So far as "the wildfire thing" being garbage where discussions of climate change are concerned, I disagree. Long-term changes in climate patterns will result in conditions becoming favorable for increasing fires in many areas: longer and deeper droughts, warmer temperatures, etc. Some places will, of course, see more precipitation, and increasing CO2 will mean more verdant growth. But places with extant forests in states of decline due to the changing climate are ripe for fire--and that's precisely what's happening.
The largest fire in New Mexico's history is still smoldering. The largest fire in Arizona's history is still smoldering. Far more of Texas has burnt this year than ever before. In 2007, Georgia, Florida, and Utah saw their largest fires ever. And so on. And that is, of course, not even counting the recent historical wildfire events in Israel, Russia, Australia, Spain, and elsewhere.
While changes in forest- and fire-management policy certainly played a role in most or all of these fires, the fact remains that things are changing, period. That conclusion is inescapable.
over millions of years, gynospores evolved to reproduce through wild fires. The plant's cone seeds release at high temperature and thrive after the blaze because of a new canopy.
This suggests to me that wild fires were extremely frequent in the past for the plant to develope such a survival strategy.
The avg. global temperature then was probably very warm.
So, its clear a warmer climate increases fire potential.
You can't. It would be a global event. Unilaterally planned.
OUCH!
Unless there are more deserts.
Only Gulfsteam Kinetic energy can stop it within ten years. Only it has the capacity to both regulate sea surface temperature and regulate electrical power output at the same time 24/7/365 if needed.
It is unstoppable. Even if man disappeared from the planet tomoorow, the world would continue to warm until it had reached its 'equilibrium' level.
Most of the warming from man made greenhouse gases does not come from the direct re-radiation of outgoing infrared radiation by those heat trapping gases. Most of the warming comes from positive feedback effects and these take time to kick in.
It's all about damage limitation for future generations. Handing over a world that's, say, 3 deg C warmer, rather than 5 deg C (or worse) if we do nothing is the aim.
Well, that's pure baloney. The majority of scientists know that atmospheric CO2 levels have risen from a pre-industrial level of 280 ppm to a current level of 393 ppm.
Sorry! That all changes if you put my plan into action. In ten years we can have it back to pre-industrial revolution temperatures.
Wait for it...
If that that's the case then the majority of the scientists are still sitting in the pot of warming water.
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Levelling off? 2010 tied 2005 for the warmest year on record at 0.63 deg C above the 1951-80 average. Where in this graph do you see levelling off?
Where are these er, "Thousands of scientists that show a cooling or lack of AGW induced warming"?
Is there a list, a site for them JB?
..or to whomever claims this?
Show us.
Not at all true. In fact, virtually all scientists agree that CO2 concentrations are rising, and the majority of them know that our unimpeded burning of fossil fuels is the reason. And a majority of scientists--an overwhelming majority of climate scientists--know that the current warming is a direct result of that.
Yes, they have, as has been demonstrated here and elsewhere repeatedly. Some may be under the impression that if they simply close their eyes and repeat a wish often enough, it may come true ala Dorothy and her ruby slippers. But, alas, such are not the ways of science.
This is profoundly true--espcially if you hear it on Fox. ;-)
We foot the bill if we cause it to go over the top even if our part is just two percent of the warming.
Greenhouse gases make the Earth warmer at the surface by an incredible 33 deg C. Without them, Earth would be virtually a snowball in space, with perhaps a narrow tundra region near the equator where life might have a fragile toehold.
Most of that 33 deg C is due to water vapour, but since a molecule of water vapour only lasts for a few days in the atmosphere and its presence in the air is highly variable, it's not grouped with the others. Estimates vary, but two thirds of the warming might be due to water vapour, meaning CO2, methane, nitrous oxide, ozone and many trace gases contribute 11 deg C.
Estimates also vary for how much of this 11 deg C is caused by CO2, but 'slightly more than half' is usual. That means it contributes around 6 deg C directly, but that warming is responsible for some of the water vapour, so the actual figure for direct and indirect warming will be significantly more than 6 deg C.
Man has increased the amount of CO2 in the air from 280 ppm to 393 ppm, or by 40%. Methane has increased from 0.7 ppm to 1.7 ppm, or by 143%. Water vapour has increased by 4%. How can this not cause warming?
Really? 8 orders of magnitude? So the Icelandic eruption put 100 million times more sulfur dioxide into the air than scientists believed was possible? That's incredible!
(shooting fish in a barrel, here)
Hmmm. It really does say that. From the article:
In addition we demonstrate that the binary H2SO4 - H2O nucleation scheme, as it is usually considered in modeling studies, underestimates by 7 to 8 orders of magnitude the observed particle formation rate and, therefore, should not be applied in tropospheric conditions.
As I don't know what a 'nucleation scheme' is, I'm not in a position to comment.
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