Submitted by AutoModerator t3_10qwrk9 in askscience
brimbopolous t1_j6t7yes wrote
In the northern hemisphere, the shortest days of the year are around the 21 of december, but the coldest month is usually february, when days are already getting longer and the sun reaching higher in the sky as it nears spring. Does this delay between amount of sunlight and amount of heat mean that there is a cumulative effect of sun radiation on the atmosphere over the span of many weeks, as opposed to it being warmed or cooled instantly by the amount of sun radiation coming from the space? Why doesn't that acummulated radiation/heat disperse through the globe, considering it's summer at the same time at the opposite hemisphere?
KitchenSandwich5499 t1_j6w8ddu wrote
There are a bunch of factors. One of those though would be the ocean, which does take longer to change temperature.
loki130 t1_j6wjjow wrote
It's largely down to heat capacity, mostly that of water. Water requires a good bit of energy to heat up by a given amount, and it has to lose that same energy to cool down; so even though the amount of solar heating is lowest in December, the oceans and other bodies of water are still holding onto heat from summer, and will continue to cool until the rate of solar heating surpasses the rate of cooling at some point in spring.
Heat is distributed pretty widely in the atmosphere, the poles are a fair bit warmer than they would be without an atmosphere and oceans, but the transport still isn't perfect so there is a gradient (compare to somewhere like Venus, which has a thicker atmosphere of mostly greenhouse gasses and so very little temperature variation on the surface, other than that caused by altitude).
brimbopolous t1_j7awmdf wrote
Thanks for the explanation!
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