Why desert has higher temperature then tropical region?
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I often ask myself, why in desert temperature is higher then in tropics even if sun is stronger in tropics.
I finally found Equivalent potential (Theta-e) that helps me with answear. Temperature is lower in tropical region, but theta-e is higher. Vapor took heat from air. This heat is taken, when water evaporate. Here are 2 pics.
Higher temperature in desert
Higher theta-e in tropical region
Theta-e is very helpfull. In my country (Slovenija) theta-e is the same like in Italy, but temperature is lower, because humidity is higher.
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@vujacicm
https://en.wikipedia.org/wiki/Latent_heat
https://apollo.nvu.vsc.edu/classes/met130/notes/chapter2/lat_heat3.htmlAlso vegetation & avg. clouds are quite different.
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@Caefix Yes. Latent heat makes temperature lower. Theta-e is good indicator tells you, how much would be temperature if latent heat would be released. I live in humid place of Slovenia. Even if temperature is low, you steel feel hot. Theta-e is the same like in Italy. But because there humidity is lower, temperature is higher.
One exaple. Theta-e in Ljubljana is this moment 58C.
Temperature in Ljubljana is 28C
Temperature in Rome is 36C. -
@vujacicm In global scale a topic is the transport of heat in moisture from the aequator towards the poles. Remember winterstorm "Ingunn". The airmass originated near Galapagos islands, passed Popocatepetl, brought record windgusts to Norway and ended up in the polar vortex, causing a "sudden stratospheric warming".
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@Caefix Here is another thing I can not understand. In the mountains theta-e is very low. So this mean that is lower then in 500mb height. This mean there are in the mountain is more stable air then out of mountain, because theta-e increase with height. I can not understand this.
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@vujacicm 🏔🎈 https://www.weather.gov/source/zhu/ZHU_Training_Page/convective_parameters/skewt/skewtinfo.html
From there in Skew-T FAQs 3)
While potential temperature can be used to compare temperatures at different elevations and the trajectory air parcels will take (rising or sinking), equivalent potential temperature can be used to compare BOTH moisture content and temperature of the air. The equivalent potential temperature (or Theta-e as it is usually called) is found by lowering an air parcel to the 1000 mb level AND releasing the latent heat in the parcel. The lifting of a parcel from its original pressure level to the upper levels of the atmosphere will release the latent heat of condensation and freezing in that parcel. The more moisture the parcel contains the more latent heat that can be released. Theta-e is used operationally to map out which regions have the most unstable and thus positively buoyant air. The Theta-E of an air parcel increases with increasing temperature and increasing moisture content. Therefore, in a region with adequate instability, areas of relatively high theta-e (called theta-e ridges) are often the burst points for thermodynamically induced thunderstorms and MCS's. Theta-e ridges can often be found in those areas experiencing the greatest warm air advection and moisture advection. For more information on Theta-e, consult Chaston's book "weather maps" used in the Synoptic I (starting on page 127).
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@Caefix Look this picture. Here you can see that theta-e in 2m surface. Only explanation is, that there in formula is used pressure lowering in sea level.
Because on 950mb, the picture is different.
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@Caefix I think I made it. One important thing here is, that you need to transfer from Celzius to Kelvin, then calculate and transfer back to Celzius. Here is reason, why small differences make theta-e differences big.
