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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First, congrats on reaching 200; that's a whole lotta writing. I think I speak for everyone when I tell you that it is very much appreciated.
Second, those heat indices were even higher yesterday. Here are a few from Iowa:
KNOXVILLE 131
NEWTON 129
ATLANTIC 126
COUNCIL BLUFFS 126
Third, there's every indication that this kind of heat not only will become more and more normal, but likely already is:
Stanford Report Article...
NOTE: that report isn't claiming there haven't been extreme heat waves in the past; it's saying, rather, that they are going to become more frequent and more severe.
In this first image you can see the "High Pressure" Rick is talking about beautifully here on this NOAA image of the Eastern US. The storms he talks about around the periphery of the high is also known as the ring of fire in meteorology but it is not to be confused with the ring of fire in vulcanology which basically circles the pacific ocean. You can also see the clear section of the middle of the country where the suppression of rain exists because of falling air.
In this second image of the Gulf Of Mexico:
You can see how hot it is and the hotter it gets the more moisture it creates in the atmosphere thus adding to the dangerous heat wave. So oppressive heat with moisture becomes a dangerous combination for us humans. So at some point we must think of ways that we can tweak the climate back to what it was because it is becoming to dangerous for our survival. I keep reading articles like this.
13 deaths in Midwest tied to heat wave
Poultry farmers deploy fans; heat to reach East Coast later this week
OKLAHOMA CITY — The heat was on Monday for millions of Americans from the Upper Midwest to Texas and Oklahoma, where roads buckled and poultry farmers deployed fans and watered rooftops to protect flocks.
The National Weather Service put 18 states stretching from North Dakota to Texas and East to Ohio under a heat warning, watch or advisory. It said as many 13 deaths in the past week in the Midwest could be blamed on the effects of the heat.
When humidity was factored in, the heat index made it feel as hot as 110 degrees in a broad swath of the nation.
"This is unusual," said Pat Slattery, spokesman for the Weather Service. "There's no sugar-coating anything here."
In steamy Oklahoma City, 13 state government buildings at the capitol were closed after a break in a water main that shut off air-conditioning systems.
Computer systems in Oklahoma's state agencies were turned off and 1,000 employees sent home, said spokeswoman Sara Cowden of the Department of Central Services.
"We're shutting everything down that generates heat," she said.
Link
There comes a time when you have to say "you know ole CB is on to something here when he says we have to cool the GOM". People are dying folks when you going to do something about it? I have done my part don't you think?
Click here:
Link
Re part 1: if you're talking about North America, that's not what the data show:
So far as part 2, few climatologists believed that an ice age was on its way. But if you have actual proof stating otherwise, I'd love to see it.
July 18, 2011
Early sea ice melt onset, snow cover retreat presage rapid 2011 summer decline
Arctic sea ice extent declined at a rapid pace through the first half of July, and is now tracking below the year 2007, which saw the record minimum September extent. The rapid decline in the past few weeks is related to persistent above-average temperatures and an early start to melt. Snow cover over Northern Eurasia was especially low in May and June, continuing the pattern seen in April.
Overview of conditions
As of July 17, 2011, Arctic sea ice extent was 7.56 million square kilometers (2.92 million square miles), 2.24 million square kilometers (865,000 square miles) below the 1979 to 2000 average. Sea ice is particularly low in the Barents, Kara, and Laptev Seas (the far northern Atlantic region), Hudson Bay and Baffin Bay.Conditions in context
Arctic sea ice extent declined rapidly through the first two weeks of July, at a rate averaging nearly 120,000 square kilometers (46,000 square miles) per day. Ice extent is now tracking below the year 2007, which saw the record minimum September extent.
OUCH!
During the first half of July, a high-pressure cell persisted over the northern Beaufort Sea, as it did in June, and is linked to the above-average air temperatures over much of the Arctic Ocean. To date in July, air temperatures over the North Pole were 6 to 8 degrees Celsius (11 to 14 degrees Fahrenheit) higher than normal, while temperatures along the coasts of the Laptev and East Siberian seas were 3 to 5 degrees Celsius (5 to 9 degrees Fahrenheit) higher than average. By contrast, temperatures through the first half of July in the Kara Sea have been 2 to 5 degrees Celsius (4 to 9 degrees Fahrenheit) lower than average. A closer look at sea ice concentration
The sea ice extent data that NSIDC uses come from the Special Sensor Microwave Imager/Sounder (SSMIS) on U.S. Department of Defense satellites. Data from other satellites, while not as useful for studying long-term trends, can show more detail about ice cover in particular regions. Currently data from two NASA satellite sensors, the Moderate Resolution Imaging Spectroradiometer (MODIS) and Advanced Microwave Scanning Radiometer for EOS (AMSR-E), show areas of low ice concentration north of Alaska. Ice in these areas is likely to melt out in coming weeks.
Both the Northwest Passage (through the channels of the Canadian Arctic Islands) and the Northern Sea Route (along the Siberian coast) are still choked with ice. Early start to Arctic melt
When sea ice starts to melt in spring, small ponds known as melt ponds form on its surface. The small pools create a darker surface (a lower albedo) that fosters further melt. How early sea ice melt starts is one indicator of how much the ice will melt in a given year. New research by Don Perovich and colleagues shows that an early start to sea ice melt increases the total amount of sunlight absorbed through the melt season.
Data processed by researchers Thorsten Markus and Jeffrey Miller at the NASA Goddard Space Flight Center reveal that melt began earlier than normal in both the Chukchi Sea, just north of the Bering Strait, and the Barents, Kara, and Laptev seas. Surface melting on the sea ice began from two weeks to two months earlier than the 1979 to 2000 average in these areas. However, in Baffin Bay and Hudson Bay, a cool spring led to a later start for surface melt, especially in Hudson Bay. Subsequent warm conditions have nevertheless led to rapid ice melt.
Low summer snow cover in the Northern Hemisphere
As noted in our May 4 post, snow cover in central Russia retreated early in response to warm conditions this spring. Updated analyses provided by the Global Snow Cover Lab at Rutgers University reveal that snow cover remained very low for May and June. Even though some mountain regions in the U.S. and Canada saw greater-than-normal snow cover, snow cover for the Northern Hemisphere as a whole for May and June was the second lowest since the start of snow cover records in 1966.
According to David Robinson, head of the Rutgers Snow Cover Lab, a new pattern is emerging in which the Northern Hemisphere is cloaked in above-average snow during late autumn, winter, and early spring, followed by rapid melt and retreat in May and June. While snow cover varies from year to year, the far north has seen a clear trend towards less spring snow cover over the last thirty years.
Global Climate Change Indicators
National Oceanic and Atmospheric Administration
National Climatic Data Center
Climate Model Indications and the Observed Climate
Simulated global temperature in experiments that include human influences (pink line), and model experiments that included only natural factors (blue line). The black line is observed temperature change
Global climate models clearly show the effect of human-induced changes on global temperatures. The blue band shows how global temperatures would have changed due to natural forces only (without human influence). The pink band shows model projections of the effects of human and natural forces combined. The black line shows actual observed global average temperatures. The close match between the black line and the pink band indicates that observed warming over the last half-century cannot be explained by natural factors alone, and is instead caused primarily by human factors.
That should tell people if we are affecting climate in this warmer way we should be able to affect climate in a cooling way. This is why we need to get a handle on what we do with the climate. To think man has no effect is ludicrous.
The warming is not in the future it is here now. The NOAA/NASA graphs prove it. Can you dig it?
No, they didn't. And no matter how many times that particular fantasy is repeated, it'll never be true. Here, allow me to help:
Strike One: "Not true, climatologist Thomas C. Peterson of the National Climatic Data Center in Asheville, N.C., and his colleagues report in the September Bulletin of the American Meteorological Society. The team’s survey of major journal papers published between 1965 and 1979 found that only seven articles predicted that global average temperature would continue to cool. During the same period, 44 journal papers indicated that the average temperature would rise and 20 were neutral or made no climate predictions."
"When...skeptics mention previous concerns about global cooling, they typically cite media reports from the 1970s rather than journal papers —'a part of their tremendous smoke screen on this issue,' says Peterson. Among major magazines, Time and Newsweek ran articles expressing concern about the previous decades’ cooling trend, juxtaposing the specter of decreased food production with rising global population.
Strike Two: "But even a cursory review of 1970s media accounts shows that there was no consensus about global cooling among journalists, either, Peterson says. In May 1975, the headline of a New York Times article warned that 'major cooling may be ahead.' Three months later, another headline in the same paper — atop a feature written by the same reporter — stated that two recent journal articles 'counter [the] view that [a] cold period is due.'"
Strike Three: "When global warming skeptics draw misleading comparisons between scientists' nascent understanding of climate processes in the 1970s and their level of knowledge today, 'it's absolute nonsense,' Schneider says. Back then, scientists were just beginning to study climate trends and their causes, and the probability of finding evidence to disprove a particular hypothesis was relatively high. Nowadays, he contends, 'the likelihood of new evidence to overthrow the concept of global warming is small. Warming is virtually certain.'"
So, that whole "They predicted global cooling in the 70s" thing? It's out...
NOAA. (http://www.wrh.noaa.gov/psr/pns/2011/July/JanMin_ JulMax.jpg)
Then what does mean something in your opinion? That is, what if anything carries weight and credibility to you?
An article published in the American Meteorological Society's bulletin debunked that favorite of denialists myths.
The Myth of the 1970s Global Cooling Scientific Consensus by Thomas C. Peterson, William m. Connolley, and John Fleck. BAMS Spet. 2008.
"There was no scientific consensus in the 1970s that the Earth was headed into an imminent ice age. Indeed, the possibility of anthropogenic warming dominated the peer-reviewed literature even then."
Just google the title and you'll find a pdf of the article.
"Be careful not to believe or post everything you see." Perhaps you should take your own advice?
And on what basis do you make the inflammatory claim that: "Yes, this is a particular model from the theory, comprised of the old manipulated, falsified, altered, and botched data."
You are accusing the scientists involved in that research of gross scientific misconduct. What is your proof of such a slanderous accusation? Or are you ignoring you own advice again?
Your right. I remember a few scientist back then thought the Earth was cooling and wrote some convincing articles about how the Earth was cooling. However,those same scientist thought the Earth was still flat.
The Earth could be cooling. Internally. But we don't have temp records of the core and mantle. Without knowing every possible factor, then why should a conclusion be set in stone?
Answer: Continue agenda of crippling corporate fossil fuel industry profits. Once you have control of the juice, you have control of the people. Enslave through science. Carry on.
US Navy Chief Oceanographer: I Was Formerly a Climate Skeptic
Oh, yeah, now I remember: ExxonMobil press releases, websites run by ex small market TV weathermen, anti-Illuminati diatribes from Glenn Beck, etc. Got it.
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Published by Nick Sundt on Tue, 04/27/2010
The evidence of climate change is growing all around us. In this posting, we provide a summary of the key findings of the new report from the U.S. Environmental Protection Agency, Climate Change Indicators in the U.S.
For more information on the report, see our posting, U.S. Environmental Protection Agency Issues Compendium of "Climate Change Indicators" for the U.S. (27 May 2010). A PDF version of the Summary of Key Findings is available online. With the exception of bracketed text, the following is excerpted directly from the report.
Greenhouse Gases
[Details on these indicators are available here: Greenhouse Gases (PDF) (12 pp, 4.7MB)]
U.S. Greenhouse Gas Emissions. In the United States, greenhouse gas emissions caused by human activities increased by 14 percent from 1990 to 2008. Carbon dioxide accounts for most of the nation’s emissions and most of this increase. Electricity generation is the largest source of greenhouse gas emissions in the United States, followed by transportation. Emissions per person have remained about the same since 1990.
Global Greenhouse Gas Emissions. Worldwide, emissions of greenhouse gases from human activities increased by 26 percent from 1990 to 2005. Emissions of carbon dioxide, which account for nearly three-fourths of the total, increased by 31 percent over this period. Like in the United States, the majority of the world’s emissions are associated with energy use.
Atmospheric Concentrations of Greenhouse Gases. Concentrations of carbon dioxide and other greenhouse gases in the atmosphere have risen substantially since the beginning of the industrial era. Almost all of this increase is attributable to human activities. Historical measurements show that the current levels of many greenhouse gases are higher than any seen in thousands of years, even after accounting for natural fluctuations.
Climate Forcing. Climate or “radiative” forcing is a way to measure how substances such as greenhouse gases affect the amount of energy that is absorbed by the atmosphere. An increase in radiative forcing leads to warming while a decrease in forcing produces cooling. From 1990 to 2008, the radiative forcing of all the greenhouse gases in the Earth’s atmosphere increased by about 26 percent. The rise in carbon dioxide concentrations accounts for approximately 80 percent of this increase.
Weather and Climate
[Details on these indicators are available here: Weather and Climate (PDF) (14 pp, 3.3MB)]
U.S. and Global Temperature. Average temperatures have risen across the lower 48 states since 1901, with an increased rate of warming over the past 30 years. Seven of the top 10 warmest years on record for the lower 48 states have occurred since 1990, and the last 10 five-year periods have been the warmest five-year periods on record. Average global temperatures show a similar trend, and 2000–2009 was the warmest decade on record worldwide. Within the United States, parts of the North, the West, and Alaska have seen temperatures increase the most.
Fossil fuel already controls the juice what you talking about?
well at least we know what you don't like:
Gasoline, made available by Big Oil, so you can travel vast distances to retrieve goods.
Independent opinions against the Big Weather bias
Philosophical commentary by anyone not associated with Big Political Media
etc.
We got it. Lets all be of one opinion and watch the ice melt as the ancients did. Belief in any other Gods besides thy Lord shall be punished.
So, just to be sure: you're still sticking with the statement that "...the vast majority of scientists years ago thought we were on the verge of a global ice age" though it's been proven false time and again. Correct? Just wanted to make sure.
As to another part of your statement, you should know that the phrase "climate change" was actually used long before "global warming". The latter term came into vogue in the 1970s, while the former has been used since at least 1916.
"...to describe "climate change" as a recent coinage is simply false. Much like the claims that all the scientists were worried about "global cooling" in the 1970s (they weren't), such a description seeks to paint the dire warnings of climate scientists as nothing more than a fad."
And thus another denialist myth bites the dust.
What else you got?
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yes.
every energy source is owned by some corporation nowadays
The AGW theory looks more like a business competition using science scare tactics to give several meager industrial sources of energy a leg-up over the proven economic stalwarts of oil and coal.
Its a lobbyist war. Its not science.
It is time to get rid of that Monopoly!
Thanks for being aware enough to replace the word "idiotic" with a blank; such incivilities have no place here, so I do appreciate the edit.
As for the rest, I get my science from scientists, or from people--journalists, bloggers, Al Gore--who get their science from scientists. The same can not be said of most "skeptics".
I am sure many companies will be doing it. Far cry from a monopoly. The Gulfstream current,Yucatan current and Loop current is plenty wide and plenty long.
LOL! Your funny! What does this tell you about sea level rise falling? Does up mean down to you?
Oh darn it! I posted NOAA graphs again they must immediately be discounted! I forgot the refuseniks are out in full force again today.
I'd sell them to different companies to prevent a monopoly.Plus I don't think you can have a monopoly in international waters can you?
That question is often ignored. Computer models and predictions are proved wrong all the time by RANDOM occurances.
Could glaciers and sea ice melting, even rises and drops in CO2, actually be healthy for a planet made of rock and metal with water covering 70.8% of the surface?
Nahh..people that get their checks for writing books on record keeping since 1979 know better.
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