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With reference to this image...:

enter image description here

...from this recent tweet, I was wondering to what extent would Mediterranean regions be affected by the large desert areas to its South?

"Affected", here meaning that there would be higher correlation between temperature measurements between the Sahara and Malta (for example), than Malta and Iceland.

I suppose that measurements are correlated but that this correlation reduces with distance to some lower value (but not zero). The question here is, how quickly does this correlation tend to its lower value and is the distance between the "centroid" (?) of the Sahara desert to points in the Mediterranean short enough so that it can be considered an "influence"?

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  • $\begingroup$ this answer is a start earthscience.stackexchange.com/questions/2963/… $\endgroup$ – gansub Feb 22 at 10:57
  • $\begingroup$ @gansub Thank you, I was not thinking of convection but just conduction given that the sand warms up enough to create significant vertical-draft. In my mind, winds are a by-product of warming up (minus the currents because of the earth's rotation). Therefore, the desert should be creating a cell / flow of its own but given the rest of the currents around it, the effect of this cell to a particular area is probably difficult to estimate... Maybe by considering prevailing winds...but not sure how informative would that be. $\endgroup$ – A_A Feb 22 at 11:51
  • $\begingroup$ @gansub Sorry, it might not be clear from my message: There are two things: a) How much does the warming up of the column of air above the Sahara affects the temperature in other areas (original question) and b) Naturally, warmed up air is going to start to move and that movement is not isolated from its surrounding (which is the bit I did not consider initially). $\endgroup$ – A_A Feb 22 at 12:02
  • $\begingroup$ I was not referring to convection but advection of wind affecting local temperature. From this peer reviewed paper - sciencedirect.com/science/article/pii/S2212094719300349 "the onset of the IP HWs was prompted by the advection of an air mass that originated in the desertic areas of northern Africa." $\endgroup$ – gansub Feb 22 at 12:02
  • $\begingroup$ @gansub thank you, that was a really good reference. If you put together an answer along the lines of these comments it would get my vote (at least). $\endgroup$ – A_A Feb 23 at 14:42
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The mediterranian do in a way create its own climate and is partly protected from the north saharan desert by the dominating wind direction in the area.

The dominating wind direction is from west and northwest,The wind blows into the saharan desert in the direction of the equator in the winter,This creates the mild winters the mediterranian is known for.

In the summer more warm and dry air moves from the north saharan desert and into the mediterranian area,this creates the dry summer climate the mediterranan is known for.

So the north saharan desert have the strongest influence on the mediterranian climate in the summer.

you can read about it here https://en.wikipedia.org/wiki/Hadley_cell if you click on the animation you can see how the precipitation changes over the year and thereby also the temparature.

and here https://en.wikipedia.org/wiki/Mediterranean_climate

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  • $\begingroup$ Thank you, I am aware of the Hadley cell circulation but missed its interaction in this case. My initial question was based purely on proximity, without considering currents which is unrealistic. $\endgroup$ – A_A Feb 23 at 14:46
  • $\begingroup$ my answer is not a very good one and a lot of information is missing so if anybody post a better one feel free to unaccept my answer at any time.if you go to the linked pages you can find a lot more information in the sources there. $\endgroup$ – trond hansen Feb 23 at 17:30
  • $\begingroup$ Thank you for this note, I will. But until then, this would be the post, in answer form, that led me to a better understanding than my own. $\endgroup$ – A_A Feb 23 at 17:36
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The proximity of the Sahara certainly does influence the Mediterranean climate, but how much varies according to which way the wind is blowing. The presence of the Sahara has a warming effect and a desiccating effect. Winds also carry large quantities of dust to the Med and to much more distant places like Latin America. Not often, but it does happen. It isn't all that rare for southerly winds from the Sahara to bring unusually warm temperatures to Britain, and to deposit dust on our motorcars. I live here, so I should know.

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