Hot answers tagged

18

There is more to phase change than just what you see on that graph. At temperatures and pressures that support multiple states (e.g. solid and gas) you have to look at the saturation vapor pressure of the gas and the actual vapor pressure (partial pressure) of the gas -- the line on the graph represents equilibrium between the states. The differences ...


13

Yes, it's called polar motion. The rotational pole moves continuously, as you can see from the right-hand side of this figure (below) by the Earth Orientation Centre (EOC) and the International Earth Rotation and Reference Systems Service (IERS). The figure shows about 650 days of time; mjd is modified Julian day and time goes along the locus in the polar ...


11

The entire process appears to take 3,000-4,000 years, according to Valet and Fournier's May 2016 review article "Deciphering records of geomagnetic reversals," which was published in AGU's Reviews of Geophysics. The complex dynamical structure of reversals is supported by sedimentary and volcanic records. Provided that resolution is adequate, the ...


11

There are two key intermittent mid latitude circulation patterns during boreal winter. One is blocking flows, leading to the formation of blocking anticyclones. One can gauge the location of blocking events through the CPC blocking index. The other one is sudden stratospheric warming, where the winds cause a disturbance such that the temperature in the ...


7

To start with a definition, the tropopause is the boundary between troposphere and stratosphere; within the troposphere temperature decreases with increase in altitude (the temperature profile is dominated by radiative heat from the Earth's surface), whereas in the stratosphere temperature increases with altitude (the temperature profile is dominated by ...


6

It's important to identify which ice. Polar bears are arctic, and they hunt in large part on sea ice. Arctic sea ice is decreasing and the most common point used for the disappearing arctic ice is the arctic sea ice minimum, meaning, the yearly low point, usually late September, so by that definition, we'd have an ice free arctic, you know, for a few ...


6

The lack of oceanic and atmospheric currents going into and around Antarctica from equatorial latitudes means that much less heat is transported from the tropical latitudes to Antarctica compared to Svalbard. Therefore, at equal latitude (i.e. equal solar isolation), temperatures in the south are much colder. In Antarctica, at 75°S latitude most of the land ...


5

As to the questions of the flights: McMurdo is about 3.500 km from the next airport (Dunedin in southern New Zealand), while Longyearbyen is only 950 km from Tromsø. It simply is due to the distance and the entailed costs and risks of such a flight. Antarctica being a continent completely surrounded by water allows for specific climatic conditions. First of ...


5

For a very basic explanation of why poles are the way they are, note that the amount of solar radiation coming from the sun is spread over a larger area at the pole. Therefore you get less radiation per square meter. As a result it is colder. Cold air can hold less water vapour. As such it is very dry (in terms of water mass per air volume) in cold regions. ...


4

It depends on which pole. The south pole is in the middle of Antarctica, with mean temperatures of -57°C, liquid water doesn't exist there and the air is extremely dry. Therefore, I would say that it is not possible to create more ice due to the lack of liquid water. And if there were any liquid water it would freeze naturally. This will make sense if we ...


4

@kwinkunks already gave a good answer on the short time scale. On long time scales, mantle convection and plate tectonics redistributes large amounts of mass, and the conservation of angular momentum requires that the direction and speed or rotation of the Earth changes accordingly. (This is independent of the fact that the orientation of Earth's axis may ...


4

If we consider that by "Assume daily cycle and convection and so on operate as usual" you meant that all heat transport from/to the pole remain as it is today. Then, we can do a back of the envelope calculation. This calculation will at least give you an order-of-magnitude answer, and we can then consider everything that would affect the result. Currently ...


4

The primary factor determining the temperature of a planet is the radiation it receives from its sun. If this were the only factor, it would be possible to estimate its temperature using the black body radiation law, as described e.g. on Wikipedia. Based on this calculation, the size of the planet has no effect on its temperature. However, there are other ...


4

I understand following comment as part of your question: Was that climate and terrain habitable by prehistoric humans? I also assume that by "interglacial periods" you don't mean the last and current one, the Holocene. The next latest one is Eemian. The wikipedia sais on the sea level during that period: Sea level at peak was probably 4 to 6m (13 to ...


4

As per our numerical calculations it takes about ~1000 years to completely flip the dynamo, that being said the current models are not even close to the actual parameters in the earth's core because it would take a humongous time to compute way beyond the capability of current computers. We published a paper back in 2014 where we talk about the role of ...


3

The situation in the southern hemisphere is identical to the northern hemisphere, but they occur at different times of the year. In the northern hemisphere the arctic circle is situated at 66.5 degrees North. Likewise in the southern hemisphere, the antarctic circle is situated at 66.5 degrees South. Between each circle and its respective pole 24 hours of ...


1

Perhaps you are thinking about the discrepancy between true north and magnetic north. The former is where the earth's axis of rotation intersects the earth's surface in the northern hemisphere. The latter is the location where the magnetic field lines of the earth are vertical, meaning a magnetic compass will point to this location. If you follow your ...


1

Geographic axis is NOT fixed. North and south poles are NOT fixed. Ideology is reverse of what you are thinking. First suppose that Earth is rotating about some arbitrary axis => Then this axis intersects on Earth's surface at two points => Now, if you see earth from above and observe earth rotating in counter-clockwise direction then this point is ...


Only top voted, non community-wiki answers of a minimum length are eligible