Lecture 10: Introduction to global circulation of the atmosphere

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6 жыл бұрын

UPDATE: I'm making materials available for all of my lectures on my website (melstrong.org) for either those bored folks stuck at home due to the virus or teachers looking for online content. For this lecture I have a project where students use two internet tools to find large-scale weather patterns on the Earth.
In this lecture we go over the basics of big circulation patterns in the atmosphere including the ITCZ, the Hadley Cell, the subtropical highs, and the easterlies / westerlies. We also talk about the rain shadow effect and how that can cause small-scale variations in local climate.
This was originally part of the Blue Planet lecture series at the University of New Mexico. If you are interested in weather, this lecture is now part of my "weather short course" playlist, where there are another ~15 videos similar to this one.

Пікірлер: 90

@paulmarchi2600 Жыл бұрын

I finally found what I have been looking for. I will start at video number one and go through all of them. This is amazing that this information is free. Thank you for putting this out there. After a storm I experienced in Illinois traveling cross country, all I can seem to think about is the weather and how it works. Thank you so much for being so clear.

@whatabouttheearth 3 ай бұрын

Mel is the smartest Baldwin brother out of all of them

@user-hn6rm5hm4d 3 жыл бұрын

Hi, this video is beneficial to everyone want to increase their atmospheric knowledge. Im graduate student from Taiwan (not China) majoring in Atmospheric Science, and I feel this video is so readily acceptable.

@DJ99777 2 жыл бұрын

🇹🇼

@valleygirlz4491 10 ай бұрын

Taiwan 🇹🇼 🇹🇼 🇹🇼 💚💚💚💚

@BrooklandsHoneyBees 3 жыл бұрын

Thank you for this, I am currently going through your lectures and must say that your explanation on all these subjects are one of if not the best I have come across, thank you!

@MelStrong 3 жыл бұрын

Thank you very much! Hope you are saving all the bees for us...

@mitzicowell 3 ай бұрын

I'm loving this series - well done!! Super useful for me in Tucson, AZ. Can't believe I waited so long in my life to learn about weather, how cool! I mean warm. I mean cool...

@willemwelvaert 3 жыл бұрын

Mel Strong, thank you so much. i'm writing a book on clouds, metaphorically to talk about my father who was a carthesian maniac, he mesured everything. he must have hated clouds. i will recommend you and share your channel so people can follow you and you're explanations, so simple, direct and to the bone. love your work , love your cat. much respect. Belgian kisses.

@rafale89140 4 жыл бұрын

I am currently getting my pilot's license and it got interested into meteorology. Thank you for these great resources. It's fun, very well imaged with lots of examples, I really like it. Cheers!

@MelStrong 4 жыл бұрын

Thanks!

@kd6613 3 ай бұрын

🎯 Key Takeaways for quick navigation: 00:06 *🌍 Introduction to Global Circulation Patterns* - Overview of how weather patterns and winds are interconnected globally. - The focus on surface winds and their speeds across different regions, especially around the equator. - Introduction to the concept of easterlies and trade winds near the equator. 02:06 *🌀 The Intertropical Convergence Zone (ITCZ)* - Explanation of the convergence of winds from both hemispheres near the equator, forming the ITCZ. - The role of converging winds in forming cumulonimbus clouds and precipitation. - Visualization of weather patterns and the distribution of high humidity and warm temperatures across the ITCZ. 07:11 *🌧️ Observation of Cumulonimbus Clusters* - Use of satellite imagery to identify clusters of cumulonimbus clouds along the ITCZ. - Examination of precipitation patterns and their daily variation along the equator. - Introduction to infrared imaging for observing cloud temperatures and heights. 14:27 *🌬️ General Circulation Patterns and Hadley Cell* - Explanation of the Hadley cell and its role in global circulation patterns. - Discussion on high pressure systems and their influence on climate, specifically desert formation around 30 degrees latitude. - Introduction to subtropical highs and their impact on local weather conditions. 20:14 *🌀 Westerlies and Jet Streams* - Examination of the westerlies and their contribution to the global wind patterns. - Detailed look at the jet streams, including their speed and influence on weather systems. - Correlation between jet streams, temperature gradients, and the polar front. 29:48 *❄️ Polar Easterlies and Mid-Latitude Cyclones* - Introduction to the polar easterlies and their characteristics. - Explanation of mid-latitude cyclones and their formation along the polar front. - Overview of the Ferrel cell and polar cell, though less emphasized compared to the Hadley cell. 37:09 *🌧️ Dynamic Weather Patterns in Motion* - Analysis of dynamic weather patterns through time-lapse imagery. - Visualization of the constant activity within the ITCZ and the presence of mid-latitude cyclones. - The concept of dry air associated with the Pacific subtropical high and its significance. 38:17 *🌵 Understanding the Pacific Subtropical High and Rain Shadow Effect* - Insights into how dry sinking air from the Hadley Cell influences cloud formation and precipitation patterns. - Exploration of the dynamic interaction between oceanic storms and continental topography, leading to intensified precipitation on windward sides of mountains and dry conditions on leeward sides. - Introduction to the rain shadow effect, illustrating how mountains can create significantly different climates on their opposite sides due to storm intensification and weakening. 41:07 *🏞️ Storm Dynamics Over Mountains and the Rainshadow Effect* - Detailed explanation of how storms intensify when forced uphill, leading to increased precipitation, and weaken when moving downhill, leading to decreased precipitation. - Description of the storm cycle as it moves over multiple mountain ranges, showcasing the alternating wet and dry zones created by this process. - Introduction to the concept of the rain shadow effect, where mountain ranges create dry conditions on their leeward sides due to storm weakening. 46:07 *🌦️ Climate Variability Due to Topography and the Rain Shadow Effect in the Western US* - Examination of how the rain shadow effect manifests in the western United States, particularly in Washington State, through the interaction of mid-latitude cyclones, mountain ranges, and moisture sources. - Analysis of annual precipitation maps to identify regions of high and low precipitation influenced by mountainous topography. - Discussion on how the rain shadow effect, along with other factors like the subtropical high, shapes local climates, leading to extreme variability in precipitation patterns across short distances. 53:13 *🗺️ Localized Climate Effects and the Significance of Elevation in New Mexico* - Correlation between elevation and precipitation in New Mexico, explaining why areas at lower elevations, like Albuquerque, receive less precipitation due to weakening storms. - Comparison of elevation maps and precipitation data to illustrate the direct impact of topography on local climate conditions. - Discussion on the broader implications of the rain shadow effect and elevation on climate variability within the state, emphasizing the unique climate zones created by New Mexico’s diverse topography. Made with HARPA AI

@biggusdickus9809 3 жыл бұрын

I love how kitty is just chilling with you

@MelStrong 2 жыл бұрын

He is definitely the chillest of any cat

@liberteegalitefraternite7804 10 ай бұрын

Thank you. Your videos helped me pass exams for air transport pilot license 🎉

@jonathanmorgan901 Жыл бұрын

Another great lecture! This series is the best around. Thank you for putting these out for us to learn about all the beautiful processes that are occurring in the sky.

@jackflight2756 Жыл бұрын

Fantastic lecture!!! Thank you so much!!!!

@independentsparrow4825 2 жыл бұрын

Atlast I learned everything I wanted to know about Geography. Thank you ❤️

@allaheadflank 2 жыл бұрын

Thanks for recording and sharing these - you have a great teaching style!

@hristoandonov2295 4 жыл бұрын

Thank you for this lecture ! The explanation was great and with lots of visual examples.

@MelStrong 4 жыл бұрын

Thanks I hope it was helpful

@AndrewChinco 4 жыл бұрын

Your lectures are the best. Very helpful

@atanasdonev65 3 жыл бұрын

Excellent lecture, it is very helpful in ATPL theory exams for pilots, it is conveyed with mastery , it is entertaining and interesting !

@susanmessenger9052 6 ай бұрын

I wish I had this resource when I was in high school in the 1970's. My grades would have been better.....thank you Mel. From Adelaide South Australia 34.9285° S, 138.6007° E

@Phippsat99x 3 жыл бұрын

Super helpful lectures. Especially for any pilot in training!

@louiscorprew7970 3 жыл бұрын

Tons of great info, thanks for the awesome lecture! You’re co-lecturer was fantastic too. Such a beautiful kitty!

@MelStrong 3 жыл бұрын

Kitty says thanks!

@konradcomrade4845 10 ай бұрын

the Northern Westerlies are weakened, nowadays ( in 2023 ) because of all the operating wind turbines, and the winds at mid-latitudes are more likely to flow in North-South and vice versa, directly. There are prolonged periods without any wind, now too. The Northern Jet Stream could also be affected! It became weaker, more meandering, and flowing/circling farther in the North than 2 decades ago. It somehow became more resembling the famous North Polar Hexagon on planet Saturn (or the northern Pentagon or the southern Octagon on planet Jupiter) Both planets have a much deeper atmosphere than Earth and obviously stable n-fold symmetries in their atmospheric circulations! It would be an interesting study to compare those planets' atmospheres and their respective Coriolis effects!

@briken2539 Жыл бұрын

These lectures are extremely helpful. Thank you for this effort.

@Yorkie_foreverbored 3 жыл бұрын

Your description for Mid Latitude cyclones was excellent. All these explanations are incredibly into detail with noaa type explanation simplified into a format that anyone can understand. You did an awesome job Mel, hope to see another vid coming out. On a side note, I'm interested in high latitude storm systems.

@MelStrong 3 жыл бұрын

Thanks...high latitude systems are essentially the same as mid latitude systems. But at higher latitudes, the air tends to be colder, and hence drier. For that reason, storms lack the intensity and cannot generate as much precipitation. But the general pattern of events is similar.

@Yorkie_foreverbored 3 жыл бұрын

@@MelStrong Also I wonder which is stronger, The Bermuda Subtropical high, or the Pacific Subtropical High. Especially since one weak cold front in July is enough to push the "Semi-Permanent" Bermuda high southwards. Abeat for a couple days though. (I also live in Southern New England and I enjoy Record hot falls, winters and springs.) btw warm fronts aren't really cool. You explained what its like to experience one spot on. Same for Cold fronts as well. (Only in the fall are cold fronts slightly different with temps going back to where they were for 2 days until another one comes through.) Primarily in October, and November.

@MelStrong 3 жыл бұрын

@@Yorkie_foreverbored On average, the Bermuda high is stronger (meaning higher absolute pressure at the surface) and larger (geographically more expansive). I made a map showing this using archived data, but unfortunately I have no way of posting it here.

@Yorkie_foreverbored 3 жыл бұрын

@@MelStrong Although as a theoretical example, How would temperatures in New England be during the winter if The Bermuda High was located just 200 miles to our southeast? (I don't know if this can be explained easily.) right now I'm just a kid which is why I tend to ask questions. (Also I'm into Meteorology.)

@TMcConnaughhay Жыл бұрын

I came across this by accident, but I watched the whole lecture. very interesting and now I understand what causes a desert area. I always knew sparse rain, but I didn't know why. Now I know! Very interesting! Love your cat. Greetings from Phoenix, AZ

@zainaxe2589 4 ай бұрын

These lectures are high quality. Thank you

@WildBillCox13 2 жыл бұрын

Most edifying. Thanks for posting. Liked and shared.

@fraser372 2 жыл бұрын

Great this helped me organise so much of the air, temp, and rain processes into a system , previously I didn’t have it all interacting just isolated bits I appreciated but couldn’t quite assemble comprehensively. ty for that …

@MelStrong 2 жыл бұрын

Thanks...glad it helped!

@gregwalkakapil8887 Жыл бұрын

one of the best explanation...thank you!

@RonLWilson Жыл бұрын

Wow! I have learned a lot from just this one video!

@jiwonkim4794 2 жыл бұрын

Exceedingly excellent!!!

@KuldeepKumar-to5lq Жыл бұрын

Thank you from India.

@uppilir49 Жыл бұрын

Very clear detailed narrations; very useful; salutations to you Sir.

@joshtalbott9528 3 жыл бұрын

These are so helpful. I'm studying for my captain's license and wanted to better understand weather. Thank you for these videos!

@briz1965 Жыл бұрын

True. Kitimat, Northern BC rains (when I lived there) everyday almost at 3-4pm. The rain forests were grand.

@konradcomrade4845 2 жыл бұрын

44:26 California should dig tunnels through the mountains, from West to East, for channeling the major mountain runoff to the Eastern side!

@maverickngaihte5629 2 жыл бұрын

Best of the best!!

@ma.ceciliaalmeda179 Жыл бұрын

Thank you so much for sharing your lecture. This helps me a lot in explaining to my students in my envi chem class.

@williamli8708 2 жыл бұрын

;-; I am so grateful that this video exists

@m.danielbalarezovillagran92 2 жыл бұрын

Awesome lecture thanks!!!

@MelStrong 2 жыл бұрын

Thanks...hopefully it was helpful

@abdelrahmanyassin7328 5 жыл бұрын

Hi i have to thank you for sharing this very interesting lecture with us , i learned so much from it about the global atmosphere although i am not familiar with this science but i enjoyed this lecture very much and enjoyed the presentation a lot. thank u

@MelStrong 4 жыл бұрын

Thank you for your comment that is very kind of you.

@franciscoprocel5634 Жыл бұрын

Excellent

@tiffanyharris8468 Жыл бұрын

Ty so much!!!

@earnstgerhardcavan7471 2 жыл бұрын

thank you you are a genius

@rodrigobarrera1517 5 ай бұрын

As a student pilot, this info its hepful

@LongNgo-td5oi 11 ай бұрын

Great video ! Does anyone know what is the website/program with the wind patterns, the dr was using in the lecture? Thank you !

@alkei_i_am 3 ай бұрын

Thank you

@dariolorini 3 жыл бұрын

Very clear explanations of these phenomena throughout the course so far. Even clearer than some books I had to learn on: congrats! This time I just didn’t understand why, in your “rain shadow effect” example, the sinking storm gets weaker: assuming that the mountain provides rising parcels of air it should do it in both of its sides (namely left and right in your drawing). I might expect that the effect of sinking prevails on the heat coming up from the mountain surface, but still: why on one side only?

@MelStrong 3 жыл бұрын

In this case the rising/sinking air is due to the airmass being pushed up over the mountain. It is also true that the mountain itself is a heat source in the atmosphere and causes enhanced convection. But as you say, that effect happens on both sides. Superimposed on that phenomenon is the fact that the airmass must rise to go up one side of the mountain and then sink down the other side. The rising enhances convection and precipitation formation; the sinking fights it. The big island of Hawaii is a classic example - air is pushed up one side and you have rain forest. Then it slides down the other side, and you have desert.

@independentsparrow4825 2 жыл бұрын

Love from India🇮🇳

@bobbilee1094 3 жыл бұрын

I tried to go to your website to watch your lectures and i was not able to due to the fact that it is an unsecure site. i really would like to be able to visit your site because i enjoy your lectures and they help me with my earth science assignments.

@MelStrong 3 жыл бұрын

I think I finally have it fixed. I can see that some stuff isn't there anymore, but I'll slowly get those things back up.

@foxllc8748 6 ай бұрын

Thanks for your lectures. But I'm not still not good myself with upper wind current and jet stream formation. I don't found no one obvious model explaining all currents happens. Will check all your lections again! 😇🤔

@nonestanimamea9099 Жыл бұрын

my lecturer sent me here

@georgen9755 Жыл бұрын

this is Cameron , ........ winds from northeast ...... typically easterly collision converging ........ Pacific ........airlines ........intertropical convergence ............... lecturer 1

@joshntn37111 Жыл бұрын

38:22 Hurricane Katrina

@princeferdinard492 Жыл бұрын

Berry sneakers...Best sneaker plug

@apichachawarat5993 2 ай бұрын

is the air sinking at subtropical due to Coriolis effect?

@kingchezz9721 Жыл бұрын

Seems the ITCV isn't correct. Coriolis Effect is what creates such winds, then to go or push in different directions, so then how can winds "meet" at the equator if they are being pushed away from the Equator, due to Coriolis Effect???

@smudent2010 Жыл бұрын

Cats are key to the international internet algorithm

@kevin2d212 4 жыл бұрын

Great as usual. I think why that cumunimbus band slightly to the north (not straight in equator) bcz its summer in the north (16 may), and the pressure is lower there.

@MelStrong 4 жыл бұрын

The ITCZ and its associated band of cumulonimbus is never exactly at the equator. It does line up with the warmest band of ocean water. But that in turn depends not only on the seasons but also on ocean currents and locations of continents. In general though, it does drift more northward during the northern hemisphere summer. However, make sure you are not confusing cause & effect here. The warmer water promotes convection, which leads to cumulonimbus development. The convection is what is lowering the pressure at the surface. In other words, the cumulonimbus formation is causing the low pressure, and not the other way around. Some people confuse these two things.

@kevin2d212 4 жыл бұрын

@@MelStrong I see. So cumulonimbus causing low pressure not the other way around. Most weathermen always said "this area is low pressure, there might be rain/storm" create the impression its low pressure first, then cumulonimbus.

@MelStrong 4 жыл бұрын

The low pressure is caused by air rising. Usually rising air leads to cloud formation (not just cumulonimbus). So when a weather forecast is talking about a system of low pressure, what they really mean is that there is a system of rising air (usually caused by two different masses of air colliding), and consequently that rising air lowers the pressure on the ground. But that rising air will eventually form clouds and if it keeps rising then precipitation. In the case of the ITCZ, the low pressure is caused by the very hot and humid conditions at the surface, which cause pockets of air to rise and lower the pressure at the surface.

@grindupBaker 4 жыл бұрын

@@MelStrong "consequently that rising air lowers the pressure on the ground" is an exchange of cause and effect because air can only be pushed, not pulled, because the molecular bonding between gas molecules is far too weak for a tensile force. I suppose the air flows off the bulge at the top, down hill under gravity, but you would know that far better than me because I've not studied it. I suppose it's just a combination of thermal expansion and that H2O molecule is lighter than 28.8 N2/O2 but I'm only supposing until I learn more.

@MelStrong 4 жыл бұрын

As the air column expands, it runs into the stratospheric inversion and cannot continue upward. So yes, you can think of it as a bulge at the tropopause than then flows laterally away from the source of the convection. The result of this is that the overall mass of the air column is slightly less than it was if convection was not occurring, creating a lower pressure at the surface. Rising air always results in a lower pressure at the surface, whether is due to thermal expansion or forced up by colliding air masses.

@grindupBaker 4 жыл бұрын

The pictorial (the usual one) at 40:40 is incorrect for the Ferrel cell because it shows air at the top of the troposphere flowing up hill from 60 N/S to 30 N/S. Air does not flow up hill (move such that it becomes further from Earth's centre of gravity) unless a force sufficient to exceed gravity pushes it. The only 2 force types possible are (1) a giant hand is shoving the air south and up hill or (2) the weight of the tropopause & stratosphere above it at 60 N/S is greater than at 30 N/S. There's no giant hand shoving the air south because photos from space would capture that and I see no reason why the weight of the tropopause & stratosphere at 60 N/S should greater than at 30 N/S, and if there is a reason, if that is the case, then this talk and all such talks should include that explanation because, obviously, it's critically important because as the cartoon stands atmospheric physicists think that a fluid flows up hill by the force of Magic, and that's not good. So either explain, or correct the Ferrel cell bulge so that it's taller at 60 N/S than at 30 N/S rather than the present cartoon which shows it 14% taller at 30 N/S than at 60 N/S with the air at the top of the troposphere flowing up hill from 60 N/S to 30 N/S.

@MelStrong 4 жыл бұрын

The average height of the tropopause near the equator is ~20km whereas near the pole is is ~7km. The reason for this is that the warmer air along the equatorial regions causes the entire structure of the atmosphere to inflate. So if you were to follow along the tropopause from the pole to the equator, you would in fact be going "uphill", though the journal would not be as smooth as that figure implies - there would be sharp discontinuities from airmasses of different temperatures that you encounter during your journey to the equator, causing abrupt height changes in your journey. But in general you would be getting farther from the Earth as you got closer to the equator during your trip along the tropopause simply due to the overall expansion of the air column from the increased warming. Seasons change this of course - a region under a blanket of cold air during the winter will have a much lower tropopause than the same region during the summer. Also keep in mind that when you see these circulation loops as shown in this diagram, it is really a mathematical average over time. So if you were to follow a single parcel of air around, it wouldn't likely be making these direct trips across latitudes as the diagram implies. But if you were to mathematically average all the trips of all the air parcels in the atmosphere, it would approximate what we see in this diagram.

@nielsdaemen 3 жыл бұрын

30:50 I think you should have shosen the 250hPa level, thats where airliners fly and the jetstream is. 500 hPa = 18289 ft = 5576 m 250 hPa = 33999 ft = 10366 m

@MelStrong 3 жыл бұрын

The 500mb map is the level used most by meteorologists, as it represents the 'halfway' point through the atmosphere. So it is the single most useful map to make weather forecasts. At this level you can clearly see the pattern of the jetstream. Further up (say at 250mb) the jetstream is faster, wider, becomes more laminar (less wiggles), and shifts more toward the north (in the northern hemisphere). But the overall jetstream pattern is still pretty similar. And just to be clear, any pressure level does not correspond to an exact elevation. So for example the 500mb level will range from from 4.5km - 6km based on the temperature below. Near the poles it will be the lowest and over the equator is the highest. The numbers that you might find given for a pressure level (such as 5576m for 500mb) are based on an 'ideal atmosphere' which can be thought of more or less as the atmosphere you would get if you averaged the entire earth. Altimeters are initially calibrated using the 'ideal atmosphere' but of course have to be adjusted for the local temperature gradient.

@nielsdaemen 3 жыл бұрын

@@MelStrong Alright, thank you very much for explaining why 500mb is the most important level! I know the altitudes I stated are for the standard atmosphere, I should have mentioned that. Just one minor point: You stated the pressure altitude (500mb level) is "based on the temperature below". however, pressure can only depend on the atmosphere *above* a point, as is it is simply the weight of the column of air above. Now that I have your atention I would like to tell you about a weather simulation sandbox I am developping. It's an interactive 2d simulation of the atmosphere wich anyone can run in their webbrowser. It also includes a skew-t diagram to probe the atmosphere in realtime. I am currently improving the precipitation model, wich turned out to be the hardest part. I would love to be able to somewhat accurately simulate anything from drizzle to large hail. Here are some video's of an old version: kzfaq.info/get/bejne/adKXdJqVm7bDh4U.html kzfaq.info/get/bejne/qMt6hNaLuqm5gqM.html A new version will be realeased very soon. Can't wait to hear what you think about it so far!