I have just returned from a trip to Düsseldorf for work and I didn’t have any chance to post anything whilst there or even do much of surfing the internet. I managed to get a lot of artwork done and at some point I’ll be posting it, but I do not have time at the moment to do such things.
For the moment I’m going to go on about something that I find quite interesting, mearly because I get trapped by it quite a bit and end up wasting hours on Wikipedia. I’m being lazy so I won’t give it any kind of introduction I’ll just dive right in to my story. When due to fly back from Germany I realised that I didn’t know what Low Pressure meant in terms of weather systems and so I went about trying to find out. What I find facinating about this is that I can easily get lost in the swamp of information that is Wikipedia.
Generally when I’m Browsing Wikipedia, I will follow a link on a page if I don’t know what it is and it seems interesting enough to persue. Here’s my journey in Meterology.
Meterology – As we all know, or should know, Meterology is basically the study of weather, which is to say that it’s not just the study of when it will rain, shine, etc, but also the study of Meteorological phenomena including, but not limited to storm formation, tornados, etc. What one may not know and is that most of this all takes place in the Troposphere
Troposphere – This is the part of the atmosphere you live in extending between 4 miles (over the poles) to 12 miles (in tropical regions) above the earth. It contains over 99% of the atmosphere’s water vapor and 75% of it’s mass. The border between this layer and the Stratosphere (which we all know of because it’s where aeroplanes fly and it’s where most of the heat gets trapped by the ozone layer) is called the Tropopause which is a temperature inversion.
Temperature Inversion – I’ve never heard of this before and it turns out to be quite simple, though probably a lot more complex when it occurs. Inversion is just a difference from the regular way atmospheric properties change with altitude. So normally you get temperature decrease with altitude, but in some situations you get temperature increasing with altitude, as in the tropopause because in the Stratosphere temperature starts to increase with altitude. Inversion can lead to nasty pollution like smog getting trapped here and at low altitudes causing health issues, as happened in London in 1952 (I’d love to go off on a red herring about the London 1952 smog but it didn’t occur during my original search). Inversion can also surpress convection which if broken can lead to violent thunderstorms, but most interestingly Inversion can result in Freezing Rain.
Freezing Rain – As rain falls, if it passes through air that is below freezing the raindrops become supercooled (which is when a liquid or gas goes below it’s freezing point without becoming a solid). When these supercooled raindrops impact a surface they freeze which can give trees a glazed look, cause branches to break under the weight and effect the flow of air over an aircraft.
You can see I’m incredibly off track already, but I want to finish with Warm Fronts which can be the cause of freezing rain.
Warm Front – I’ve often heard the term though I’ve never really known what it is, a warm front occurs when a body of warm air moves towards a body of cold air (potentially with a below zero temperature). The warm air doesn’t have the density to mix with the cold air and so it drifts above it, which causes the warm air to expand and cool forming clouds (high cirrus). As more air cools in this region and forms clouds they thicken into cirrostratus and altostratus and once they have reached 2,500km from the earth’s surface rain can begin to fall from the nibostratus clouds.
I don’t know the names of the clouds but there aren’t any direct links in Wikipedia and it’s at this point that I realise I still don’t know what Low Pressure really means in terms of weather and I give up for another day. Maybe I’ll find out what Low and High pressure really mean for weather one day, but for now I’m off to bed.