# Tag Info

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 ...

12

Roughly put, it's the same thing that makes a density step function when you try to combine oil and water: Source The components do not mix with or dissolve into each other, so gravity makes the denser material -- water -- settle to the bottom. The density as a function of height jumps up from the oil density to the water density when you go below the ...

11

There's some kind of explanation about the units under the picture. The formula is based off the average temperature in degrees Celsius (measured over the entire year, and the entire Earth), which is 15.04 at sea level, and the temperature decreases by 0.00649 degrees every meter above sea level (the average lapse rate). The formula is 'valid' until 11 ...

10

Where to start.... If you take a look at midlatitude weather on any given day, you will find a pattern of upper tropospheric winds that look like this (source: NWS): . Notice how it looks like a wave? These are called Rossby waves. You may imagine that the jet stream is imbedded in the ups and downs of these pressure contours. If we take a look at a typical ...

8

Your issue is an issue for all types of mining near residential or built up areas, not just manganese mining. The distance that mines should be from built up areas depends on the competency of the ground whether the ground is hard or soft the type of explosive used - more particularly the energy released by the explosives used. This influences the blast ...

8

1.2 x 10^13 kg equals 12,000,000,000,000 l water. One liter equals 0.001 m³, while one km³ equals one billion (1 x 10^9) m³. So we're supposedly adding 12 km³ water to the atmosphere per year. According to wikipedia the total oceanic surface is about 361,900,000 km². If we spread the added amount of water over all the oceans, we end up with a sea level rise ...

8

Pollen is one of many types of cloud condensation nuclei (CCN). So can you make clouds without pollen? Yes, but you still need other sources of CC. Don’t fall into the false dilemma that pollen is a requirement for cloud formation. The more soluble the CCN is, the easier it is to form a cloud (see Koehler theory). Can a cloud be formed without CCN? I saw it ...

7

How can the air in the Earth's shadow scatter blue light if it doesn't get any direct illumination, and any indirect illumination getting back there should be VERY depleted in blue (i.e. mostly red light)? You're completely right. If you simulate light scattering only, you'll get exactly this result: a sandy-colored sky, with a bit redder belt of Venus, and ...

7

The equation for relative humidity is $$RH=100\times \frac{e}{e_s(T)}=100\times \frac{e_s(T_d)}{e_s(T)} \tag{1}$$ Where $T_d$ is the dewpoint temperature and $T$ is the temperature, $e$ is the water vapor pressure, and $e_s$ is the saturation vapor pressure, which is also known as the Clausius Clapeyeron equation. While the previous link has a decent ...

5

The factor of 1000 may be related to the expected units. The mass 'units' can be found in the derivation. The full derivation of mixing ratio goes like this $$w=\epsilon\frac{e}{P}$$ since, by the ideal gas law, $$e=\rho_vR_vT$$ and $$P_d=\rho_dR_dT$$ then the mixing ratio is expressed as $$w=\epsilon\frac{\rho_vR_vT}{\rho_dR_dT}=\epsilon\frac{\rho_vR_v}{\... 4 Assuming you are talking about ethanol: it is a common chemical substance, generated naturally from e.g. rotting fruits. So any pollution from hand sanitizers should be negligible. What happens to the alcohol in the atmosphere is an interesting sequence of reactions. I took the info below from an article (see link below). In the air, ethanol is oxidized ... 4 You may be forgetting that pressure also decreases with height (exponentially). Also, because P=\rho R T, \frac{dP}{dT}=\rho R (that is, c_p does not appear). But I digress in answering your question. Let's break down why potential temperature increases with height. Let's start with the equation:$$\theta=T\left(\frac{P_0}{P}\right)^{\frac{R_d}{c_p}}\...

4

If we'd be living in a dry atmosphere your reasoning is indeed correct. Air would rise adiabatically and air would loose about 9.8 °C/km (dry adiabatic lapse rate). This means constant potential temperature. However, Earths atmosphere isn't dry. As soon as a rising, moist air parcel reaches saturation, it will rise with a moist adiabatic lapse rate (6-7 °C/...

4

Δ𝐸=133.26+0.044[𝐶𝑂2] It’s just a numerical coincidence that the 0.044 looks like the molar mass of CO2. That equation gives 0.044 * 380 = 16 W/m2, which is the reduction in surface downwelling IR if you remove all the CO2 from the present day atmosphere (e.g., see Table 1 of Zhong and Haigh, 2013, Weather, https://doi.org/10.1002/wea.2072, pdf). Looking ...

3

By Hydrostatical Law, $p_a = \rho gh$, at a given $h$. However density varies with altitude and with temperature. Temperature varies by altitude. $g$ constant varies with altitude. That expression is for water, which has more or less constant density, and it is for depth rather than height. Ynou need to change this to a differential equation. This is fairly ...

3

I took a class once, and we had an approximate equation for an particle (equation sheet is still up): $$\frac{d\vec{v}}{dt}=\frac{\rho_{particle}-\rho_{air}}{\rho_{particle}}\vec{g}-\frac{3\rho_{air}C_D}{4\rho_{particle}CD_{particle}}\vec{v}|\vec{v}|$$ where $\rho$ is density, $\vec{g}$ is the gravity vector (usually $=g\hat{k}$ but can be changed if the ...

3

But when we look at some diagrams, Earth's atmosphere is thick. For instance, when someone says that the atmosphere is a thin sheet of air, does he/she take in to account the thick layer thermosphere or exosphere? Or is it just that the diagrams we commonly see have inaccurate visual representation? You are probably referring to diagrams such as this one, ...

3

The answer to your question depends on where one defines the edge of the atmosphere. The Earth's atmosphere is layered. The thickness, density of composition of each layer varies. The five layers are: Exosphere: 700 to 10,000 km (440 to 6,200 miles) Thermosphere: 80 to 700 km (50 to 440 miles) Mesosphere: 50 to 80 km (31 to 50 miles) Stratosphere: 12 to 50 ...

3

I agree with the comments; some upfront research would be good here, even at a basic level. A good place to start is this Wikipedia article, which gives not only atmospheric heights but also other characteristics such as composition and the behavior of molecules. In terms of heights the Wikipedia article suggests 700 km for the lower boundary of the ...

3

As I said in my comment, viruses aren't my area (concerning units). But the answer is actually unitless. The exact answer you seek is dependent on a couple of different variables: The speed of the exhalation (cough or breathing)+speed of wind The atmospheric stability Of course, the viral load of the exhalation is also important, but since you're asking ...

3

The law that governs the pressure of gas at equilibrium over a dissolved liquid is called Henry's Law. Note, the equilibrium assumption, as there is some time dependence. That is, if you start with no dissolved gas in pure water, then in a relatively short amount of time, the amount of dissolved gas will be less than equilibrium. Let's talk in abstractions. ...

3

First, let's acknowledge this fact: $$c_p=R+c_v \tag{1}$$, where $R$ is the specific gas constant. This means that $x=R/c_p$. Rearranging the equation, we can see that $$P+I=\int{c_p\left(\frac{P}{P_{00}}\right)^{R/c_p}\Theta dM}\tag{2}$$ Notice that $\left(\frac{P}{P_{00}}\right)^{R/c_p}$ is the Exner function. By extension,$$P+I=\int{c_p T dM}\tag{3}$$ If ...

3

What oxygen shortage? Earth's atmosphere contains 20.9 percent oxygen. There's a lot of oxygen in the atmosphere and its depletion rate from burning fossil fuels has been small. Humans have been burning fossil fuels on an industrial scale for a long time: coal fired power stations, internal combustion engines in cars, trucks, train locomotives, aircraft and ...

3

Clouds don't really form in a fully stable atmosphere, so the distinction between "stable" and "unstable" is not real here. An approaching warm front in particular offers many types of clouds, and among other types one may well see high-altitude cirrus, cirrocumulus and cirrostratus clouds appearing together. Beach weather approaching ... ...

2

I've found two sources for molecular hydrogen. The photolysis of formaldehyde (See chemical formula 10 and see Novelli et al. 1999) Anthropogenic sources. While it isn't a source I think I should mention the exosphere. The exosphere is not very dense, so hydrogen (probably) doesn't react with anything. Since it is the lightest element, it probably doesn't ...

2

Besides man-made sources, hydrogen can be produced naturally through a process called serpentization. Mafic and ultramafic rocks, which are rich in magnesium and iron silicates, react with water to produce a variety of breakdown products summarized in the Wikipedia article on serpentine Serpentinization is a geological low-temperature metamorphic process ...

2

It seems your question was more like a thinking exercise rather than a question. I cannot answer your question with robust confidence in the current state of knowledge. The fact is, I have always shared your skepticism on the matter, particularly when being taught this subject matter in graduate classes by the experts who work in the field! What I can offer ...

2

ANSWER: $h={\Delta}t/{\Delta}l$ $h=$ height of LCL (unit depends on unit height of lapse rates) ${\Delta}t=T-T_d$ ${\Delta}l=l_t-l_d$ $T$ is surface temp (deg) $T_d$ is surface dewpoint temp (deg) ${\Delta}l=$ difference between lapse rates (deg) $l_t=$ dry adiabatic lapse rate of temperature (deg/unit height) $l_d=$ lapse rate of the saturation mixing ratio ...

2

I didn't really understand where did this "one-sixth of the escape velocity" figure come up from. The "one-sixth of the escape velocity" a ballpark number. As a general rule, three sigma events (events that are three standard deviations from the mean) happen all the time, while twelve sigma events are so very, very rare that they can ...

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