What causes the weather? (not the seasons)

  • #26
I understand what you mean. That's precisely why I also gave the other scenario of comparing the general weather conditions from one summer to the next as well. I'm finding it difficult to get my point across. I'll try one more time:


The scenarios I presented are examples of how unpredictable and chaotic the climate system is. It seems to me that if we truly understood all the factors, then the climate system/weather should be a lot more predictable and uniform. Yet, it’s highly chaotic and highly unpredictable. As such, does that mean there are 1 or more random factors that we’re unaware of, or random factors that we are aware of, but miscalculating or underestimating their affect?

OR:


Is it a matter of “predictably”, “uniformity” and "chaos"are subjective terms in this regard, and my massive weather changes scenarios fall within the known parameters? In other words, it's more predictable and uniform than I think?
 
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  • #27
DaveC426913
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Yet, it’s highly chaotic and highly unpredictable. As such, does that mean there are 1 or more random factors that we’re unaware of, or random factors that we are aware of, but miscalculating or underestimating their affect?
This is a basic misconception.

A system doesn't have to have random factors or factors we are unaware of in order to be effectively unpredictable.

We first have to disabuse you of such preconceptions.
 
  • #28
Well at that point, we would have to define what exactly we mean by "random", and I sure the heck don't want to go there.

Is it more a matter of what I said in my previous post? That is:

Is it a matter of “predictably”, “uniformity” and "chaos"are subjective terms in this regard, and my massive weather changes scenarios fall within the known parameters? In other words, it's more predictable and uniform than I think?
 
  • #29
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@Seth Anthony, what is your actual goal in this thread?
You already received tons of very good answers, and you keep to ignore them. Endless restating of your question will not help you to get deeper understanding of the topics involved. You should now take the hints given to you more seriously, and read about the concepts. Otherwise the discussion is pointless.
 
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  • #30
I'm not ignoring them. I believe I've come to the point to which I stated in my previous post. That is:

The terms of “predictably”, “uniformity” and "chaos"are subjective in this regard, so it seems "my massive weather changes" scenarios fall within the known parameters. In other words, the climate (in the known parameters) is more predictable and uniform than I thought.
 
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  • #31
TeethWhitener
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Wait, are you only comparing the temperature at one location on the Earth year after year, or are you looking at the global average? Because the global average is fairly predictable (no wild 30-degree swings year-over-year). The other one is not: you do know that black cars sitting in the sun get hotter than white cars, right? And that things on the Earth are different colors? And that things like clouds and ice are really reflective, so they bounce sunlight back into space more easily than bare land or water? And and and and and...The weather would be variable even if the system were not chaotic, because the globe is variable.
 
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  • #32
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The terms of “predictably”, “uniformity” and "chaos"are subjective in this regard, so it seems "my massive weather changes" scenarios fall within the known parameters. In other words, the climate (in the known parameters) is more predictable and uniform than I thought.
This doesn't make sense to me. What exactly is subjective about these terms? Additionally, the discussion started about weather and now you make conclusions about climate. It is not the same.
You can make whatever statements you like, but do they improve your actual understanding?
 
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  • #33
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The scenarios I presented are examples of how unpredictable and chaotic the climate system is. It seems to me that if we truly understood all the factors, then the climate system/weather should be a lot more predictable and uniform. Yet, it’s highly chaotic and highly unpredictable. As such, does that mean there are 1 or more random factors that we’re unaware of, or random factors that we are aware of, but miscalculating or underestimating their affect?
We don't understand all the factors. For example, we only recently (within the last decade or so) managed to accurately model a tornado and account for which inflows and outflows power it. And this is a fairly small local phenomenon. There are many factors to account for, and we just don't know about all of them nor do we fully understand the ones we do know about.

On top of that, we have an issue of how we model weather and climate. Ideally, we would use 'first principles' in our computational models since they should give us the most accurate results. However, this is often impossible due to the sheer number of different parameters and particles we'd have to use, so we have to develop shortcuts that make it possible to make a model in a usable time frame. But these shortcuts aren't as accurate, and sometimes they are just downright wrong.

Don't fully believe me? Then try developing a simulation that can make an accurate model of the airflow produced by a fan placed in a 1x1x1 meter sealed box. First try it by modeling every single gas particle. When your computer melts or crashes from memory overflow you'll understand what I'm saying. :wink:

In any case, that only addresses how we model and predict the weather/climate. It does nothing to address your original question.
 
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  • #34
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Summary:: Why can the weather be drastically different on July 31st 2020 compared to July 31st 2019?

One winter can be mild and snow free, while the next winter is a frozen wasteland. One summer can be blistering hot, while the next is rather cool. More specifically, if you take that example down to the day, then why can the weather be drastically different on July 31st 2020 compared to July 31st 2019? The earth's tilt and distance from the sun is no different between those dates, and solar output is seemingly about the same for those two dates. So what changed between those dates to cause, let's say, a massive 30 degree temperature change? In other words, why wouldn't the weather be exactly the same on those two dates?
Basically the reasons for yearly variability in temperature are often explained by some variability in the way the energy is distributed within Earth's system. Higher latitudes are actually dependent on the energy conveyed by the ocean and the air circulation cells from the Equator and Tropics to the Poles. Variations in temperature in a region between two years is often caused because of a variability in the way other regions received or kept thermal energy. There is a chain of causes and effects to reach a certain temperature in a region and this chain of causes and effects depends on other regions too.

I understand this is not something easy to understand so I can give you a few excerpts from various institutional websites to draw a general picture of the Earth's system.

There are differences between external and internal forcings:

There are numerous mechanisms that may produce climate variations or change. One is external forcing, which contains both natural and anthropogenic sources. Examples of natural external forcing include solar variability and volcanic eruptions. Examples of anthropogenic forcing are from changing concentrations of greenhouse gases and aerosols, and land cover use produced by human activities. A second involves internal mechanisms within the climate system that alone can produce climate variations. Internal mechanisms include processes that are due primarily to interactions within the atmosphere as well as those that involve coupling of the atmosphere with various components of the climate system. Climate variability due to purely internal mechanisms is often called internal variability.
Source: https://psl.noaa.gov/csi/whatis/
The ocean is important thermal regulator of the Earth's climate because of its large thermal capacity and its large volume, this is why it is nicknamed sometimes "Earth’s biggest heat bucket".
Seasonal temperature extremes are milder near large bodies of water and more extreme further inland because water is slower to heat up and to cool down than air or even land. The ocean (as well as other large bodies of water) have considerable "thermal inertia". They warm slowly as heat is added, but also give up that heat slowly as their surroundings cool.
Source: https://scied.ucar.edu/longcontent/transfer-and-storage-heat-oceans
One way that the world’s ocean affects weather and climate is by playing an important role in keeping our planet warm. The majority of radiation from the sun is absorbed by the ocean, particularly in tropical waters around the equator, where the ocean acts like a massive, heat-retaining solar panel. Land areas also absorb some sunlight, and the atmosphere helps to retain heat that would otherwise quickly radiate into space after sunset.

The ocean doesn't just store solar radiation; it also helps to distribute heat around the globe. When water molecules are heated, they exchange freely with the air in a process called evaporation. Ocean water is constantly evaporating, increasing the temperature and humidity of the surrounding air to form rain and storms that are then carried by trade winds. In fact, almost all rain that falls on land starts off in the ocean. The tropics are particularly rainy because heat absorption, and thus ocean evaporation, is highest in this area.

Outside of Earth’s equatorial areas, weather patterns are driven largely by ocean currents. Currents are movements of ocean water in a continuous flow, created largely by surface winds but also partly by temperature and salinity gradients, Earth’s rotation, and tides. Major current systems typically flow clockwise in the northern hemisphere and counterclockwise in the southern hemisphere, in circular patterns that often trace the coastlines.

Ocean currents act much like a conveyor belt, transporting warm water and precipitation from the equator toward the poles and cold water from the poles back to the tropics. Thus, ocean currents regulate global climate, helping to counteract the uneven distribution of solar radiation reaching Earth’s surface. Without currents in the ocean, regional temperatures would be more extreme—super hot at the equator and frigid toward the poles—and much less of Earth’s land would be habitable.
Source: https://oceanexplorer.noaa.gov/facts/climate.html
If you want to visualize some effect of the ocean, NASA made an interesting video on the topic with the title "The Ocean: A Driving Force for Weather and Climate".

Finally, the most important part to understand is the role of air pressure on weather:

Pressure varies from day to day at the Earth’s surface - the bottom of the atmosphere. This is, in part, because the Earth is not equally heated by the Sun. Areas where the air is warmed often have lower pressure because the warm air rises. These areas are called low pressure systems. Places where the air pressure is high, are called high pressure systems.

A low pressure system has lower pressure at its center than the areas around it. Winds blow towards the low pressure, and the air rises in the atmosphere where they meet. As the air rises, the water vapor within it condenses, forming clouds and often precipitation. Because of Earth’s spin and the Coriolis Effect, winds of a low pressure system swirl counterclockwise north of the equator and clockwise south of the equator. This is called cyclonic flow. On weather maps, a low pressure system is labeled with red L.

A high pressure system has higher pressure at its center than the areas around it. Winds blow away from high pressure. Swirling in the opposite direction from a low pressure system, the winds of a high pressure system rotate clockwise north of the equator and counterclockwise south of the equator. This is called anticyclonic flow. Air from higher in the atmosphere sinks down to fill the space left as air is blown outward. On a weather map, you may notice a blue H, denoting the location of a high pressure system.
Source: https://scied.ucar.edu/learning-zone/how-weather-works/highs-and-lows-air-pressure
As you see, it has a huge importance for the wind direction and the way the air mass behave.

BUT the effect goes beyond this, the air masses with a particular air pressure are affected by their surroundings with a different air pressure and are affecting them as well:

When the air in one region is warmer than the surrounding air it becomes less dense and begins to rise drawing more air in from underneath it. Elsewhere cooler denser air sinks pushing air outward to flow along the surface and complete the cycle. The constant movement of these accumulations of air is called Fronts.

What are the Types of Weather Fronts

When large masses of warm or cold air move throughout the atmosphere they carry their own differences and characteristics. The boundary between the air masses is part of the front. Usually, hundreds of miles long, when a front passes through a region, it changes the weather. There are four types of Fronts and they are:
  • Cold Fronts-When a cold air mass pushes under a warm air mass forcing the warm air to rise.
  • Warm Front-This forms when warm moist air slides up and over a cold air mass.
  • Stationary Front– This front occurs when warm and cold air meet and neither air mass has the strength to push the other they remain standing still
  • Occluded Front-This front occurs when warm air mass gets caught between two cold air masses. The warm air masses rise and the two cold masses meet in the middle.
What are Cold fronts

When Cold fronts come through the weather becomes windy and gusty. There is a sudden drop in temperatures. Thunderstorms and heavy rainfall with hail can develop. These dramatic changes in the weather are fast and violent. They can move twice as fast as a warm front. Atmospheric pressure changes fast from falling to rising. After the Cold front moves through the area, the temperatures become cooler.

The rain will stop and Cumulus Clouds are replaced by Stratus clouds or with clear skies. On a weather map, the cold front is represented by a blue line. Triangle will show the direction the front is moving in. You will always see temperatures in front of the blue line are warmer than the temperatures in the back of the line after the front moves through. The front will cool the area in that down considerably.

What are Warm Fronts

Warm air fronts move slowly because it’s more difficult for the warm air to push against the cold dense air. The types of clouds that are associated with a warm front are located high in the sky. As the warm front passes over the area the clouds become lowered and rain is more likely.

There can be thunderclouds around this front if the air is unstable. On a weather map that you normally see on the evening news, the warm air front is represented by a red line and the red semi-circles indicate the airflow direction. The temperatures on the ground will normally be cooler in front of the red line than warmer after the front moves through.

What are Stationary Fronts

Stationary fronts happen where the masses of warm and cold air won’t move and are kind of standing off with each other but neither one is strong enough to move the other one aside. This front can stay put for days unless the wind direction changes or the system breaks apart. The weather with this type of front is normally cloudy and rain or snow will often fall according to the temperature.

Especially if the front is in a low atmospheric pressure area. On a weather map, a Stationary Front looks like an alternating red line with semi-circles and blue triangles. The blue triangles point in one direction while the red semi-circles point in the opposite direction.

What is Occulted Fronts

Sometimes cold fronts follow right behind warm fronts. The fronts push against each other but because the cold fronts move faster it will normally take over. This occurrence is called Occulted Front. At an occluded front, the cold air normally forms around low atmospheric pressure and there is often precipitation that follows. Winds will change direction as this front moves through the area.

The temperatures can either cool or warm as it passes through the region. On a weather map, an Occulted Front looks like a purple line that contains half triangles and half semi-circles along it pointing in the direction of movement of this front.

Fronts are Made Up of Air Masses

Air is all around us and when you feel the air start to move it could be that the weather is about to change. The way the air moves effects the weather because wind carries heat and cold temperatures as well as moisture to one place or to another. How these winds pass each other affects a region that day. The air is classified by masses there are four main air masses that are according to the geographical part of the earth they are associated with.
  • Polar Maritime- An air mass that is typically warm and moist
  • Polar Continental Is the air that is cold and dry in the winter.
  • Tropical Maritime is the air that is warm and moist
  • Tropical Continental is the air that is warm and dry
The movement of these Air Masses makes up the Fronts and their interactions with landmasses affect weather in those areas.

The fronts of these air masses can carry pressure differences that make wind happen are caused by differing conditions behind the air in each front. When two of these air masses bump into each other it can create a storm or other change in the weather.

How fast it moves and how different they are in temperature at the time they move into each other dictates the severity of the oncoming weather event. If the two systems collide into each other at too quickly a speed it could cause a cyclone.

Source: https://mywaterearth.com/what-causes-changes-in-weather/
I hope now you are beginning to understand how dependent to surrounding conditions is the weather of a region and why seasons are different year-to-year.

To go further, there are also long-term internal oscillations in the climate system that make each year different to another.

Climate Variability: Arctic Oscillation
https://www.climate.gov/news-features/understanding-climate/climate-variability-arctic-oscillation

Climate Variability: North Atlantic Oscillation
https://www.climate.gov/news-featur...limate-variability-north-atlantic-oscillation

Climate Variability: Pacific - North American Teleconnection Pattern
https://www.climate.gov/news-featur...ability-pacific-north-american-teleconnection

Long Distance Relationships: the Arctic and North Atlantic Oscillations
https://www.climate.gov/news-featur...tance-relationships-arctic-and-north-atlantic

Polar vortex brings cold here and there, but not everywhere
https://www.climate.gov/news-featur...tex-brings-cold-here-and-there-not-everywhere
 
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  • #35
Evo
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Summary:: Why can the weather be drastically different on July 31st 2020 compared to July 31st 2019?

Hello.

One winter can be mild and snow free, while the next winter is a frozen wasteland. One summer can be blistering hot, while the next is rather cool. More specifically, if you take that example down to the day, then why can the weather be drastically different on July 31st 2020 compared to July 31st 2019? The earth's tilt and distance from the sun is no different between those dates, and solar output is seemingly about the same for those two dates. So what changed between those dates to cause, let's say, a massive 30 degree temperature change? In other words, why wouldn't the weather be exactly the same on those two dates?

When I've posed this question to a couple of climatologists, I received the suspected answers of ocean currents, uneven heating, cloud formation, etc, yet, none of those reasons actually answer my question. Those answers are symptoms, not causes.

I suspect the answer is fluctuations in solar radiation, but both those climatologists denied that. So what's the answer?
Have you heard of El Niño and La Niña?

What are El Niño and La Niña?
El Niño and La Niña are complex weather patterns resulting from variations in ocean temperatures in the Equatorial Pacific.

Warmer or colder than average ocean temperatures in one part of the world can influence weather around the globe. Watch this Ocean Today video to see how this works.

The term El Niño refers to the large-scale ocean-atmosphere climate interaction linked to a periodic warming in sea surface temperatures across the central and east-central Equatorial Pacific.

Typical El Niño effects are likely to develop over North America during the upcoming winter season. Those include warmer-than-average temperatures over western and central Canada, and over the western and northern United States. Wetter-than-average conditions are likely over portions of the U.S. Gulf Coast and Florida, while drier-than-average conditions can be expected in the Ohio Valley and the Pacific Northwest. The presence of El Niño can significantly influence weather patterns, ocean conditions, and marine fisheries across large portions of the globe for an extended period of time.
La Niña episodes represent periods of below-average sea surface temperatures across the east-central Equatorial Pacific. Global climate La Niña impacts tend to be opposite those of El Niño impacts. In the tropics, ocean temperature variations in La Niña also tend to be opposite those of El Niño.

During a La Niña year, winter temperatures are warmer than normal in the Southeast and cooler than normal in the Northwest.
https://oceanservice.noaa.gov/facts/ninonina.html

This is why the "weather" can vary so much. If after all of the previous posts and this you still do not understand changes in the weather from year to year, it's time to close this thread.
 
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  • #36
256bits
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Have you heard of El Niño and La Niña?
He should have by now.
I already posted about the subject in #12.


You get some likes and responses , but for some reason my post was overlooked completely.
Same information. Different messengers I suppose.
:smile:
 
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  • #37
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I received the suspected answers of ocean currents, uneven heating, cloud formation, etc, yet, none of those reasons actually answer my question. Those answers are symptoms, not causes.
I think this part is, what confusing you. Those things are both cause and effect in the same time: effect of past causes and causes for the future effects.

In short, the cause of (future) weather is, that we do have weather right now :wink:
 
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