Barometric pressure and global warming

Yep, look up Hadley cells. The short answer is that temperature differences create pressure differences that set up global atmospheric circulation patterns. But first look up the ideal gas law. I could have added some links, but you need to do your homework.

If you want to get an explanation of the whole context, find an entry level meteorology textbook. Google will point you to lots of articles on the specific topics, but a meteorology text will put it all together in a more cohesive way.

Or ask your friendly local neighborhood storm chaser. Since Twister came out, they're everywhere!

Thanks. The Ideal Gas Law is what brought this to mind. I just wasn't sure if weather patterns would show the correlation with any relevance.

So here is the bigger question: With all the hype about GW, why has BP not ever been used as a supporting indicator to the phenomena?

Generally, barometric pressure is not something that is tracked statistically, except for hurricanes. The central pressure of a tropical low has a known relationship to the strength of the system, and this is shown in the Saffir-Simpson scale of hurricane strength. The lower the pressure, the stronger the system.

I don't know if anyone has studied barometric pressure in relation to GW. I imagine that first they would have to establish a theoretical basis for showing that more heat in the atmosphere will cause changes in barometric pressure readings, and what those changes would be. Then look to see if such changes show up in the records. I'm not advocating looking only for supporting evidence, but first determine according to already established science what the evidence should look like, and then see if any such evidence shows up.

Barometric pressure is probably not tracked because it's not something that people feel or sense, so less value is placed on it. Temperature, rainfall, and snowfall are example of weather conditions that do affect people, and so the daily readings of those items are processed into averages and norms.

Now, the vapor pressure of water vapor is something that people do feel, and it does affect how people behave, but it is not tracked. Because this relates to relative humidity, that is the one condition that is reported as both RH and dewpoint temperature.

I'm sure the data on barometric pressure is stored at the NCDC, but extracting it and processing it into the form needed for the GW study would be time consuming and expensive.

Won't work.

If you heat a balloon you still have the same weight of air inside, you just have a bigger balloon. Heating the atmosphere doesn't make it lighter, just bigger. It still exerts the same force on earth, somewhere.

That's how I see it.

What won't work?

If you heat a balloon, the air has the same mass, but the air becomes buoyant. Air heated at the surface by the sun or heat radiating from the surface will also become buoyant, especially if the air is moist.

You might be thinking of the atmosphere as a whole. However, the atmosphere is not heated evenly.

I could say more, but as I told the OP, do your homework.

"the air becomes buoyant"

Less dense, maybe. If we assume that "the air becomes buoyant" we assume that there is a more dense substance to displace the air and push it up.

We only have more (cooler) air coming in to replace the buoyed air. It's more dense because it's cool.

This is giving me a BIG headache!!!!!!!!!!!!!!!!!!!!!!!!!!!

And, I'm almost out of beer.

OK, I'll give you a hint. It's called parcel theory.

You might also want to check the website of your local NWS office to see if they are conducting Skywarn training in your area. Or come to Tulsa on Feb. 28 for the annual all day session. If Tulsa is too far, the National Storm Chaser Convention is next weekend in Denver.

I'll get back to you after I do my homework.

Maybe my problem is just one of semantics.

Or, perhaps, a firm lack of knowledge on the subject?

LL

OK,

I now know enough about parcel theory, theory to confirm that it is local, not global.

I guess that I am thinking of the entire atmosphere, and not just a chunk of it.

Thanks for making me learn something new!

LL

I must commend you on being a good student. You did your homework and learned something you didn't know. That makes you a learner, not just a student. Students study, learners learn. Study doesn't necessarily lead to learning, it is just one thing that can lead to learning. I've had the thought that if I were ever to teach a class, I'd tell the people that I don't want them to be students but learners.

I must say thanks for the opportunity to help someone learn.

BTW, ever hear of Warren Faidley or Susan Strom? They are a couple of storm chasers and lightning photographers from your state. If you'd ever met either one, I'm sure they'd be glad to answer any questions you'd have.

Here's something cool: ACRE is involved in retrieving 250 years worth of data including barometric pressure readings from old ships' logs: SENABAR (Storminess and climate change from European and North Atlantic BARometric pressure variability since 1800)I guess the BP was pretty important for sailors in the day...

The barometer reads local atmospheric pressure, which is a function of the mass of air above the instrument. It is similar to measuring the depth of water by the pressure on the bottom.

The total mass of air above the earth is fairly constant, so the total "hydrostatic" pressure on the global surface will be fairly constant, regardless of the temperature. Local differences result from local heating or cooling, so in a "high" the mean temperature is less (the air more dense) than in a "low". Winds tend to equalize the pressure, but because of the Coriolis acceleration the winds cannot blow directly from high to low pressure, and the pressure differences persist for a while.

Barometers have been around for centuries, and meticulous records are kept. Computer models for weather forecasting are based on pressure measurements, then predicting wind velocity.

Bottom line: Global warming will not significantly change the mass of the atmoshere, so the barometric pressure, on average, won't change.

Thanks to all so far. I am not being lazy. I just really don't know much about the matter and did some cursory study (yes 3 doug, study) of the subject and quickly became curious as to why or why not BP would/would not be used as an indicator of GW.

It seems to me that there would be localized increases, even if only seasonal, of BP that could support or refute the theory of GW as a true global phenomena or if in fact it is more a localized event.

However, I have never once heard it mentioned in any context as a GW point of interest. And as we established the ideal gas law tells us that it should be? Shouldn't it?

Hey look! square one again!

"And as we established the ideal gas law tells us that it should be? Shouldn't it?"

The ideal gas law would tell us that increasing the temperature would increase the pressure <<in a fixed, an enclosed, volume>>. However, the atmosphere is open at the top. The barometric pressure is the result of mass and gravity, both of which are independent of temperature.

Ahh. Yes. Thank you for pointing out that, er umm er, slight(?) oversight on my part.