• Question: how does the sun create our weather

    Asked by jmadelin1 to Cassie, Greg, Karen, Sofia, Tommy on 13 Nov 2013. This question was also asked by jrourke.
    • Photo: Thomas Doherty-Bone

      Thomas Doherty-Bone answered on 13 Nov 2013:

      I am a bit dubious about the word “create”, you’ll find scientists can be funny about the wording of things.

      Weather is a summary of the conditions at a particular place at a particular time. For example, it was sunny, dry but cold this morning in Leeds, but when I drove to the western Yorkshire Dales in the afternoon, it was cloudy with some rain…and still cold 🙁

      Contrast to climate, which is an averaged summary of weather over a longer time period (i.e. cold and raining in Britain most of the time vs. hot and dry in the desert).

      So what does the Sun do? Well you know it rises and sets. This influences the weather by heating up the part of the Earth exposed to it. This might cause clouds to rise, and for humidity (water in the air) to increase. This will be very apparent in very hot countries. In very hot areas, with little forest, the heat pushes the water well away and out of the area in clouds. The tilt of the Earth as it orbits will influence which part of the non-tropical hemispheres will get summer or winter. In summer, there will be more plants active, which in turn regulate the water cycle, which also regulates humidity and rainfall.

      Its all very complicated, but consistent….providing the tilting of the Earth doesn’t change, the orbits don’t change and the Earth stays roughly the same distance from the Sun.

      Hope this helps, let me know if you have further queries to this.

    • Photo: Karen Bacon

      Karen Bacon answered on 14 Nov 2013:

      So this is another tough one! Weather is something that happens day-to-day (as you know) and isn’t really caused directly by the sun, except that the sun of course keeps our planet hot enough for us to live on. The sun gives energy to our atmosphere and then for a whole lot of very complicated interactions between the atmosphere, the oceans and the land we get weather that changes day-to-day. The science of predicting the weather is incredibly complex and uses a type of maths called “chaos theory” which should tell you something about how hard it is! Weather can also be affected by human activity – for example burning lots of fossil fuels can create smog, which will then hang around in the sky and can increase rainfall. Cities are always hotter than the surrounding countryside (this is called the urban heat island effect) because of the energy created by people moving around, using electricity and driving cars, buses, vans etc.
      So although the sun is ultimately responsible, weather is very complicated and caused by lots of different interacting factors. The orbit of the Earth also helps to cause weather – winter and summer are due to changes in the tilt of Earth’s orbit, and this changes the weather we get for a few months. The Earth also has long-term cycles in its orbit that can effect climate (climate is different to weather – weather happens day by day but to have a particular climate you need broadly similar weather for around 30 years. So to say that the climate is getting hotter or colder, you need at least 30 years of increasing or decreasing temperatures). The orbital cycles are called Milankovitch cycles are can effect climate on 10,000; 21,000 and 41,000 year cycles – they were partly responsible for the last set of ice ages.

    • Photo: Sofia Franco

      Sofia Franco answered on 19 Nov 2013:

      I think they got it pretty much covered! Though the sun hugely influences the weather, it does no create it…it is all a function of the suns influence, latitude and longitude (e.g. which will affect temperature), with atmospheric phenomena, landscape physiognomy (e.g. mountains can affect the weather), water and landmasses (e.g. water masses affect evaporation), and load of other things! I bet a meteorologist would be perfect to answer you 😉 but we do our best!

    • Photo: Cassandra Raby

      Cassandra Raby answered on 20 Nov 2013:

      Eeeek! I’m glad everyone else managed to come up with good answers to this!