54
Water is a rather strange substance. With most substances, the solid phase is denser than is the liquid phase. This is not the case with water. Ice is less dense than liquid water. A side effect of this effect is that liquid water very close the the freezing point is less dense than is slightly warmer water. That very cool water sinks.
Liquid fresh water ...
53
Water melts at 0 °C (32 °F) but freezing is a more complicated affair. It is safe to say water gains the ability to freeze at 0 °C, but it can get much cooler before it actually does so resulting in supercooled water. Water in this state can rapidly solidify when suitable ice nuclei are introduced. For example, in convective clouds, liquid water can be ...
52
How it's possible to measure temperature 2000 years ago?
Sans the technology used by Bill and Ted ("Bill and Ted's Excellent Adventure"), it obviously is not possible to directly measure the temperature from yesterday, let alone 2000 years ago, or longer. What is used are "proxies", things that can be measured today that serve as stand-...
36
Does human body temperature impact climate change? Directly? It's not even a blip. The Earth's population is 7.6 billion. With each person radiating about 80 watts (basal metabolism), that's about 600 gigawatts, or 760 gigawatts using a round figure of 100 watts. That sounds like a lot, but it's only a tiny fraction of the 18 terawatts consumed by humanity, ...
31
According to Wikipedia an approximate average surface temperature for a bare earth is 274.5 K. This scenario is quite reasonable in my opinion as stripping the atmosphere without changing much else would (on a geological timescale) rather quickly result in a bare earth without ice caps or vegetation, causing circumstances quite close to those on the moon. (I ...
30
The Earth is always radiating heat to the space. But in the day the Sun delivers some heat. The net heat flux is then defined as the sum of those two factors. If the energy delivered by the Sun is bigger than the cooling rate, the Earth is net warming (positive net flux – we can imagine it like heat is travelling "to us"), as opposed to the ...
24
I am interpreting your question as referring to rivers with flowing water freezing as as opposed to glaciers, which are already frozen.
Under current climatic conditions, small rivers can freeze throughout: from bank to bank, surface to river bed. I'm avoiding using the word solid as some people use that word when a river's surface has frozen from bank to ...
24
This phenomenon is known as global dimming.
It was due to the particles and aerosols mostly released by combustion of fossil fuels such as diesel. Those particles block the radiation from the sun, so they have a cooling effect. For some decades this effect counterbalanced the warming effect of greenhouse gases, although it is no longer the case at a global ...
23
It is straightforward to do so with numpy, scipy.interpolate.griddata, and matplotlib. Here is an example:
import matplotlib.pyplot as plt
import numpy as np
from scipy.interpolate import griddata
# data coordinates and values
x = np.random.random(100)
y = np.random.random(100)
z = np.random.random(100)
# target grid to interpolate to
xi = yi = np.arange(...
21
Due to convection (the cold water sinks while the warm water rises), the entire pond needs to be brought to near-freezing temperatures before the surface can freeze. With only the top of the pond in contact with the cold air, this takes a long time.
Additionally, the ground (which is not cooled by convection) will take even longer to cool down, ...
20
I bet you live on the eastern half of North America, which had a cold winter of 2013-2014, Europe and Alaska had a very warm winter, and China had its second warmest January.
Jennifer Francis of Rutgers has been advocating the Arctic or Polar Amplification theory (Wikipedia). In which she hypothesises that warming of the Arctic has been greater than lower ...
19
The record the article is referring about seems to be the same as registered at Guiness World Records:
On 13 September 2012 the World Meteorological Organisation
disqualified the record for the highest recorded temperature, exactly
90 years after it had been established at El Azizia, Libya, with a
measurement of 58°C. The official highest recorded ...
18
Polar regions are colder than equatorial ones for a simple reason - geometry.
More specifically, it is caused by the greater angle of the Sun's rays to the surface of the Earth. As you go farther north, the Earth's (mostly) spherical surface bends back from the direction of the Sun's rays, and the same amount of photons are spread over a larger area.
What'...
17
The amount of surface heating from the sun is a function of time of year and latitude. You are aware of the dependence on the time of year with the sun over the equator at the equinoxes and ~ $\pm$23$^\circ$ N at the solstices. The varying position of the sun overhead means the projection of a solid angle from the sun onto the surface of the earth will ...
17
The answer is because the Earth is not a static system.
Due to the ideal gas law, air cools as it rises. This is referred to as the dry adiabatic lapse rate. However, you are curious why every location on earth is not the same temperature at the same latitude. We know this is not true. But why is not true? Weather.
The earth, as with most natural ...
17
There is several credibility problems with this work.
First, they mention after the title:
Abridged Research Report
but I cannot find any related full work from the authors on the matter. As a comparison, in this case, a short, simplified article was prepared as a companion for a full paper. The former is useful for news agencies and general public, ...
17
NWS Temperature forecast or new forecast
From these URLs, it appears that the unit is Fahrenheit.
and if you click on this URL - Max/MinT
Is the maximum daytime or minimum overnight temperature in degrees Fahrenheit.
In the USA NWS always used to issue forecasts and bulletins in Fahrenheit and some background can be obtained from here US Customary ...
15
Not much at first. The damage has already been done. Humanity has added at least 100 gigatonnes of carbon to the atmosphere since the start of the industrial age. Natural sequestration of that excess carbon is a slow process. Suppose all human production of carbon ceases (and note that vehicular production of CO2 is but a fraction of the total). It will take ...
15
Is there a correlation between temperature and cloud, during the night?
Very much so. It's called radiative cooling. Three factors come into play: cloudiness, relative humidity, and windiness. Nighttime radiative cooling is greatest under clear skies, low relative humidity, and light or no winds. The temperature drop (in degrees per hour) can be a factor of ...
15
This is a good overview of ocean surface currents, which includes a schematic like this one:
In the mid-latitudes, you get gyre circulations that move poleward along the eastern coasts of continents (the western edges of the ocean), bringing warm water. The water off the east coasts of these places is thus warmer than you would expect for that latitude. The ...
14
Ozone does not "filter" UV, it absorbs UV radiation (and undergoes some photo-chemistry reactions in the process). By absorbing those wavelengths it prevents them from reaching us at the surface, but cause a temperature rise in the stratosphere.
We have plenty of gasses that behave this way for terrestrial radiation (however without the photo-chemical ...
14
Photosynthesis increase in the northern hemisphere spring, especially in the Siberian Taiga, and carbon dioxide decrease in atmosphere. During autumn and winter, decomposition of plant material and increased combustion, bring more carbon dioxide to the atmosphere. Measurements from e.g. the South Pole shows the same pattern, but much less and in opposite ...
14
The water in a pond is in contact with the ground and the ground is not even close to freezing even if the air temperature is 27° below freezing.
14
The traditional answer basically comes down to the physics concept of adiabatic cooling, a description of which is:
There is less pressure as you go up in the atmosphere (basically due to less air weighing down)
Air takes up more volume at lower pressures
Since there's nothing else to supply the energy needed to expand, the air employs the energy that was ...
14
That device only shows Fahrenheit
I don't know about the full Weather Service, but that device only shows Fahrenheit measurements. You can see this in the user manual, in the appendix, page 18
13
It depends on the season. The figures below shows zonal mean temperature for June-July-August from ECMWF ERA-40 reanalysis. As you can see, at 100 hPa, the equator is actually colder than the sunlit hemisphere.
June-July-August
December-January-February
For getting the "facts" on this kind of questions, the ECMWF ERA-40 atlas is a good source. Now as to ...
13
This is a very good question. There a few main heat sources: Heat(and work) left over from the formation of the earth, work (potential energy) generated by dense iron sinking into the center of the earth and forming a core, and radioactive energy. Since the Thermal diffusivity of the materials that make up the earth is low, heat transport is very slow and ...
13
Whether the high temperatures of the core is strictly necessary to maintain a habitable temperature at the surface I'm not sure, as the global temperatures are largely controlled by insolation and the greenhouse effect. The black-body radiation temperature of the Earth is about -18 °C, and even a more realistic estimate of the surface temperature ...
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