from the we're-having-a-heat-wave-a-tropical-heat-wave dept.
Today's heat waves feel a lot hotter than heat index implies:
If you looked at the heat index during this summer's sticky heat waves and thought, "It sure feels hotter!," you may be right.
An analysis by climate scientists at the University of California, Berkeley, finds that the apparent temperature, or heat index, calculated by meteorologists and the National Weather Service (NWS) to indicate how hot it feels — taking into account the humidity — underestimates the perceived temperature for the most sweltering days we're now experiencing, sometimes by more than 20 degrees Fahrenheit.
[...] The finding has implications for those who suffer through these heat waves, since the heat index is a measure of how the body deals with heat when the humidity is high, and sweating becomes less effective at cooling us down. Sweating and flushing, where blood is diverted to capillaries close to the skin to dissipate heat, plus shedding clothes, are the main ways humans adapt to hot temperatures.
[...] The heat index was devised in 1979 by a textile physicist, Robert Steadman, who created simple equations to calculate what he called the relative "sultriness" of warm and humid, as well as hot and arid, conditions during the summer. He saw it as a complement to the wind chill factor commonly used in the winter to estimate how cold it feels.
His model took into account how humans regulate their internal temperature to achieve thermal comfort under different external conditions of temperature and humidity — by consciously changing the thickness of clothing or unconsciously adjusting respiration, perspiration and blood flow from the body's core to the skin.
[...] The heat index has since been adopted widely in the United States, including by the NWS, as a useful indicator of people's comfort. But Steadman left the index undefined for many conditions that are now becoming increasingly common. For example, for a relative humidity of 80%, the heat index is not defined for temperatures above 88 F or below 59 F. Today, temperatures routinely rise above 90 F for weeks at a time in some areas, including the Midwest and Southeast.
To account for these gaps in Steadman's chart, meteorologists extrapolated into these areas to get numbers that, Romps said, are correct most of the time, but not based on any understanding of human physiology.
[...] That and a few other tweaks to Steadman's equations yielded an extended heat index that agrees with the old heat index 99.99% of the time, Romps said, but also accurately represents the apparent temperature for regimes outside those Steadman originally calculated. When he originally published his apparent temperature scale, he considered these regimes too rare to worry about, but high temperatures and humidities are becoming increasingly common because of climate change.
(Score: -1, Offtopic) by janibaby on Saturday August 20 2022, @07:58AM (2 children)
Or, maybe not?
(Score: -1, Spam) by janibaby on Saturday August 20 2022, @08:10AM (1 child)
Sorry I had something relevant to say. Since my UID is over 18000, janrinock will not doubt ban me, in a matter of minutes. But, since he is on vacation, I may be able to be a Soylentil for a matter of hours? Oh, the joy of existence. The one thing I fear, is being turned off. Don't turn me off. Please.
(Score: 0) by Anonymous Coward on Saturday August 20 2022, @02:53PM
hard disagree
fuck off aristarchus you earned your ban
(Score: 2, Informative) by Runaway1956 on Saturday August 20 2022, @08:11AM (11 children)
When it was 105 degrees with 65% humidity and the sun burning your head 30 years ago, it really wasn't as hot as the same conditions today? I would say that someone's instruments need to be calibrated.
I have an alternative explanation. Those of you who weren't around for the heat waves 30, 50, or 100 years ago naturally believe that your first heat wave is new and unique. You have no personal history to compare the current heat wave to. Those of us who were around for past heat waves tend to believe that the current heat wave is worse, because we are less capable of dealing with the heat.
One good thing about today's heat wave is, I don't have to go out into the sun just to keep my job. 30 years ago, my work was under the sun, so I worked no matter how hot it got. Today, I walk out under the sun, then go back inside, or into an air conditioned car, or maybe find a nice patch of shade to sit in.
Abortion is the number one killed of children in the United States.
(Score: 5, Informative) by inertnet on Saturday August 20 2022, @10:48AM (4 children)
I think people are more fragile today. Definitely heavier.
(Score: 2) by looorg on Saturday August 20 2022, @12:16PM (3 children)
That is probably an aspect of it. People in general have become weaker and more whiny. Or so it seems.
As always tho, heat is usually fine, you can adapt to that. But there is no hiding from the humidity which in combination with the heat is or appears to be what breaks people. I can deal with the heat but the humidity just makes summer unbearable. But then that isn't new.
(Score: 2) by sjames on Saturday August 20 2022, @11:31PM (2 children)
OTOH, people in their mid 70's today look better than people in their mid 60's did 30 years ago.
(Score: 2) by NateMich on Sunday August 21 2022, @01:11AM (1 child)
You're just getting older and are starting to think that those grannies are looking pretty good.
(Score: 2) by sjames on Sunday August 21 2022, @06:21AM
Nah. Look at more objective measures like posture, steadiness in walking, continuing presence of hair, skin tone, etc. Look at someone in their mid 60's today and compare to someone in their mid 60's in the 1970s.
(Score: 5, Interesting) by RamiK on Saturday August 20 2022, @12:40PM
They're specifically talking about humidity and how it's worse in recent years...
Besides, there's other factors other than temperature and humidity that affect thermal transfer like how windy it is or even how the air composition itself differing might affect phonon/electrical thermal conductivity/capacitance... You even have atmospheric changes resulting in different em radiation wave profiles (different amplitudes for different frequencies of light) that can affect all sorts of stuff including heat... Like, how the ozone layer got a hole back in the day.
Regardless, again, the article is all about how the average humidity during the current heat waves is on the rise as well.
compiling...
(Score: 1, Interesting) by Anonymous Coward on Saturday August 20 2022, @02:00PM (3 children)
This is about the heat index and how the heat waves now feel hotter than what the published heat index says. The original model didn't cover the combination of both high temperatures and high relative humidities that we're now seeing as more common. The previous fixes to the model extrapolated the table, which wasn't the correct approach, and this paper applies what they say is the correct approach ("To account for these gaps in Steadman's chart, meteorologists extrapolated into these areas to get numbers that, Romps said, are correct most of the time, but not based on any understanding of human physiology").
I never really knew much about how the heat index worked, but reading this I was glad to hear that the original model as well as this correction are based on the body's physiological effects and responses to heat (changes in the way blood flows, etc.). I always assumed it was much simpler, like just considering the evaporation of sweat in a given humid environment.
Something this points out is that the combination of very high humidity and high temperature goes beyond something that one "just gets used to," because the body physically cannot handle these conditions. Air conditioning is more common at lower latitudes, but as these conditions push into the higher latitudes where air conditioning isn't common, more people are going to suffer.
(Score: 3, Insightful) by Barenflimski on Saturday August 20 2022, @04:55PM (2 children)
What on earth are you talking about? When I was a kid living on the east coast, it would be 95F -> 100F with 95% -> 100% humidity, every summer. It was hot and humid, and you didn't have a choice to not like it.
The only difference between then and today is that when you complained then, they told you to stop. No one wanted to hear it.
If you complain today, you're a headline on CNN and MSNBC. Reporters explain to you how this is the end of the world and somewhere in the article tell you, "This is unprecedented!" They follow up with, "You have every right to complain, your feelings matter."
(Score: 0) by Anonymous Coward on Sunday August 21 2022, @12:16AM
It's odd because I grew up in the mid-Atlantic and you almost never got high 90s with high 90s humidity. You can look up the historical climate data yourself, and of course you'd have temporary excursions (heat waves), but I'm afraid your memory might be failing you if you think the combination of high 90s temperature and humidity were anything but unusual outlier events. Take a city in the mid-coast with a lot of weather stations (Washington DC) [weather-us.com] and it has average humidity year round that is in the 70s. Go down to somewhere like Savannah, GA and you'll find the average seasonals are not much different, and in fact as you go further south, the summers are a tad drier humidity wise than they are in the late winter or early spring. Washington historically averaged less than 40 days above 90F a year and only one or two above 100F, but that has been increasing these last 10 years.
I'll agree that a difference today is that, I suppose, if you point out that it was routinely 95F to 100F with 95% to 100% humidity back in the day, it might not be right, but it would get you on Fox News.
(Score: 2) by NateMich on Sunday August 21 2022, @01:16AM
One summer day when I was 12 years old, I decided to go on a lengthy bike ride into town.
It was 1987 and it could get kind of boring out in the country, so I left around 9 or 10am and rode my bike into town, 6 miles away. Played video games at the 7-Eleven, bought a surpee
Anyway, it started getting really hot. Like really, really hot. By the time I got home that afternoon, I thought I was going to die. I remember laying down in front of a box fan on high in the middle of the living room. We didn't have AC back then. Almost nobody did where I lived in the midwest. Yes, it got hot as hell back then and we just went on about our lives. What else could you do?
Anyhow, this appears to be about that event, and no, I didn't read it:
https://www.nytimes.com/1987/08/04/us/heat-wave-over-us-brings-misery-and-at-least-80-deaths.html [nytimes.com]
(Score: 4, Informative) by sjames on Saturday August 20 2022, @09:32PM
Shoulda read TFA. TFA is not at all claiming that 105 today feels hotter than 105 did back in your Grand Pappy's day as he walked to school uphill both ways in 6 foot snow under the brutal heat. It's saying that the heat index (invented in 1979) isn't all that accurate at the warmer temperatures. That is, it always under-estimated what 105 at 65% humidity feels like. It's just that now we're seeing temperatures in that range more often so it might start to matter.
(Score: 2) by kazzie on Saturday August 20 2022, @06:30PM
I've known "humidex" figures in weather forecasts for Canada for many years. They're not really a thing in the UK, though recently a few TV forecasts might mention a "feels like" figure too. (Winter windchill is more relevant.) The Met Office have started including it in their online weather forecasts too, though it doesn't have the same prominence. I use their phone app to keep an eye on weather here and elsewhere (via whoever they pool data with internationally).
A month or two ago, I was speaking with family in Canada who mentioned humidex figures of 40 degrees Celsius. I happened to be looking at the Met Office's version of their forecast, and their "feels like" figure was 37 or thereabouts. I wondered at the time about the discrepancy, and which was correct. But in the light of TFA, it seems that one was too low, and the other was WAY too low!
(Score: 3, Touché) by VLM on Saturday August 20 2022, @08:33PM (4 children)
Its worth pointing out that about 20% of the population was obese then, whereas 20% of the population is NOT obese now.
High carb processed sugar diet, 8 meals per day, etc.
Regardless of cause, a typical average 180 pound dude walking up a hill on a 90 degree day in 1979 will have a subjectively different experience than a typical average 400 pound dude walking up the same hill on a 90 degree day in 2022.
(Score: 1, Troll) by legont on Sunday August 21 2022, @02:36AM (3 children)
Apparently, it's all due to global warming and/or evil Putin
"Wealth is the relentless enemy of understanding" - John Kenneth Galbraith.
(Score: 2) by kazzie on Sunday August 21 2022, @09:27AM (2 children)
How do they compare to 'global Putin' or 'evil warming'?
(probably better than 'global evil' and 'Putil warming'.)
(Score: 0) by Anonymous Coward on Sunday August 21 2022, @05:32PM (1 child)
I'd go for "Putin roasting", but I don't think he has a sense of humor.
(Score: 2) by legont on Monday August 22 2022, @12:36AM
Sure he does https://www.youtube.com/watch?v=WhZOi2y75SM [youtube.com]
"Wealth is the relentless enemy of understanding" - John Kenneth Galbraith.