The flow of the atmosphere generally moves in a west to east direction. This, however, can often become interrupted, creating a more north to south or south to north flow. These scenarios are often described in meteorology as zonal or meridional. These terms, however, tend to be used about localized areas of the atmosphere (at a synoptic scale). A fuller explanation of the flow of atmosphere around the Earth as a whole can be found in the three-cell model.
Atmospheric flow
Troposphere
Troposphere | Atmospheric flow
Sorry. I cannot find the answer based on the context. It differs from most liquids in that it becomes less dense as it freezes. Sorry. I cannot find the answer based on the context. Water differs from most liquids in that it becomes less dense as it freezes. In 1 atm pressure, it reaches its maximum density of at .
what are the alternating dark and light bands in jupiter’s atmosphere called
user
Lightly colored "zones" and relatively dark "belts."
assistant
what is the atmosphere like in jupiter?
user
It is mostly made of molecular hydrogen and helium in roughly solar proportions; other chemical compounds are present only in small amounts and include methane, ammonia, hydrogen sulfide, and water.
assistant
how can you describe its structure vertically?
user
The atmosphere of Jupiter is classified into four layers, by increasing altitude: the troposphere, stratosphere, thermosphere and exosphere
assistant
what is the definition of the first mentioned layer?
user
The troposphere is the lowest layer of Earth's atmosphere, and is also where nearly all weather conditions take place.
assistant
what is the flow here like?
user
The flow of the atmosphere generally moves in a west to east direction.
assistant
are there different types of flow?
user
Yes, Zonal flow, Meridional flow and Atmospheric flow
assistant
how do you explain the first type of flow?
user
A zonal flow regime is the meteorological term meaning that the general flow pattern is west to east along the Earth's latitude lines, with weak shortwaves embedded in the flow
assistant
how is the third type of flow?
user
Sorry. I cannot find the answer based on the context.
assistant
what is the density of the last chemical compound found in the planet?
user
It is a quantity commonly retrieved by remote sensing instruments, for instance the Total Ozone Mapping Spectrometer (TOMS) which retrieves ozone columns around the globe. Columns are also returned by the differential optical absorption spectroscopy (DOAS) method and are a common retrieval product from nadir-looking microwave radiometers. A closely related concept is that of ice or liquid water path, which specifies the volume per unit area or depth instead of mass per unit area, thus the two are related: Another closely related concept is optical depth.
Area density | Atmospheric physics
This is what the composition is "about"" (p. 71).
Density 21.5 | Structure
Further note that since g, Earth's gravitational acceleration, is approximately constant with altitude in the atmosphere, the pressure at height h is proportional to the integral of the density in the column above h, and therefore to the mass in the atmosphere above height h. Therefore the mass fraction of the troposphere out of all the atmosphere is given using the approximated formula for p: For nitrogen, it is 75% , while for oxygen this is 79%, and for carbon dioxide - 88%.
Density of air | Total content
Higher than the troposphere, at the tropopause, the temperature is approximately constant with altitude (up to ~20 km) and is 220 K. This means that at this layer L = 0 and T= 220K, so that the exponential drop is faster, with H = 6.3 km for air (6.5 for nitrogen, 5.7 for oxygen and 4.2 for carbon dioxide). Both the pressure and density obey this law, so, denoting the height of the border between the troposphere and the tropopause as U:
Density of air | Tropopause
The flow of the atmosphere generally moves in a west to east direction. This, however, can often become interrupted, creating a more north to south or south to north flow. These scenarios are often described in meteorology as zonal or meridional. These terms, however, tend to be used about localized areas of the atmosphere (at a synoptic scale). A fuller explanation of the flow of atmosphere around the Earth as a whole can be found in the three-cell model.
Troposphere | Atmospheric flow
The mean mass of water vapor is estimated as 1.27 kg and the dry air mass as 5.1352 ±0.0003 kg."
Atmosphere of Earth | Density and mass
Since charge is conserved, current density must satisfy a continuity equation. Here is a derivation from first principles. The net flow out of some volume "V" (which can have an arbitrary shape but fixed for the calculation) must equal the net change in charge held inside the volume: where "ρ" is the charge density, and "dA" is a surface element of the surface "S" enclosing the volume "V". The surface integral on the left expresses the current "outflow" from the volume, and the negatively signed volume integral on the right expresses the "decrease" in the total charge inside the volume.
Current density | Continuity equation
The planet's density is extreme for its amount of mass. It implies the existence of an amount of heavy elements with a mass between about 140 and 300M.
CoRoT-13b | Introduction
The three-cell model of the atmosphere attempts to describe the actual flow of the Earth's atmosphere as a whole. It divides the Earth into the tropical (Hadley cell), mid-latitude (Ferrel cell), and polar (polar cell) regions, to describe energy flow and global atmospheric circulation (mass flow). Its fundamental principle is that of balance – the energy that the Earth absorbs from the sun each year is equal to that which it loses to space by radiation. This overall Earth energy balance, however, does not apply in each latitude due to the varying strength of the sun in each "cell" as a result of the tilt of the Earth's axis concerning its orbit.
Troposphere | Three-cell model
By volume, dry air contains 78.08% nitrogen, 20.95% oxygen, 0.93% argon, 0.04% carbon dioxide, and small amounts of other gases. Air also contains a variable amount of water vapor. Except for the water vapor content, the composition of the troposphere is essentially uniform. The source of water vapor is at the Earth's surface through the process of evaporation. The temperature of the troposphere decreases with altitude. And, saturation vapor pressure decreases strongly as temperature drops. Hence, the amount of water vapor that can exist in the atmosphere decreases strongly with altitude and the proportion of water vapor is normally greatest near the surface of the Earth.
Troposphere | Composition
As mentioned previously, is found in both diffuse and dense molecular clouds. By applying the reaction rate constants ("α", "β", and "γ") corresponding to all of the currently available characterized reactions involving , it is possible to calculate "k"("T") for each of these reactions. By multiplying these "k"("T") by the relative abundances of the products, the relative rates (in cm/s) for each reaction at a given temperature can be determined. These relative rates can be made in absolute rates by multiplying them by the . By assuming for a dense cloud and for a diffuse cloud, the results indicate that most dominant formation and destruction mechanisms were the same for both cases.
Hydronium | Interstellar chemistry
The average density of Earth is . Because the average density of surface material is only around , we must conclude that denser materials exist within Earth's core. This result has been known since the Schiehallion experiment, performed in the 1770s. Charles Hutton in his 1778 report concluded that the mean density of the Earth must be about formula_1 that of surface rock, concluding that the interior of the Earth must be metallic. Hutton estimated this metallic portion to occupy some 65% of the diameter of the Earth. Hutton's estimate on the mean density of the Earth was still about 20% too low, at .
Structure of Earth | Core
Consider a small element of area A and length dx as shown in the figure (right). Applying conservation laws on this element, formula_1-density V-velocity of the element
Compressible duct flow | Calculation
The density of air at sea level is about 1.2 kg/m (1.2 g/L, 0.0012 g/cm). Density is not measured directly but is calculated from measurements of temperature, pressure and humidity using the equation of state for air (a form of the ideal gas law). Atmospheric density decreases as the altitude increases. This variation can be approximately modeled using the barometric formula. More sophisticated models are used to predict orbital decay of satellites. The average mass of the atmosphere is about 5 quadrillion (5) tonnes or 1/1,200,000 the mass of Earth. According to the American National Center for Atmospheric Research, "The total mean mass of the atmosphere is 5.1480 kg with an annual range due to water vapor of 1.2 or 1.5 kg, depending on whether surface pressure or water vapor data are used; somewhat smaller than the previous estimate.
Atmosphere of Earth | Density and mass
The density falls off to below 10 e/cm at night.
F region | F1 and F2 layers
When the zonal flow buckles, the atmosphere can flow in a more longitudinal (or meridional) direction, and thus the term "meridional flow" arises. Meridional flow patterns feature strong, amplified troughs of low pressure and ridges of high pressure, with more north–south flow in the general pattern than west-to-east flow.
Troposphere | Meridional flow
Fluid that is less dense than its surroundings tends to rise until it has the same density as its surroundings. If there is not much energy input to the system, it will tend to become stratified. On a large scale, Earth's atmosphere is divided into a series of layers. Going upwards from the ground, these are the troposphere, stratosphere, mesosphere, thermosphere, and exosphere. The density of air is mainly determined by temperature and water vapor content, the density of sea water by temperature and salinity, and the density of lake water by temperature. Where stratification occurs, there may be thin layers in which temperature or some other property changes more rapidly with height or depth than the surrounding fluid.
Geophysical fluid dynamics | Buoyancy and stratification
Vapour density is the density of a vapour in relation to that of hydrogen. It may be defined as mass of a certain volume of a substance divided by mass of same volume of hydrogen. vapour density = mass of "n" molecules of gas / mass of "n" molecules of hydrogen. vapour density = molar mass of gas / molar mass of H
Vapour density | Introduction
Discussion of the layers in the Earth's atmosphere is needed to understand where airborne pollutants disperse in the atmosphere. The layer closest to the Earth's surface is known as the "troposphere". It extends from sea-level to a height of about 18 km and contains about 80 percent of the mass of the overall atmosphere. The "stratosphere" is the next layer and extends from 18 km to about 50 km. The third layer is the "mesosphere" which extends from 50 km to about 80 km. There are other layers above 80 km, but they are insignificant with respect to atmospheric dispersion modeling.
Atmospheric dispersion modeling | Atmospheric layers
To calculate the density of air as a function of altitude, one requires additional parameters. For the troposphere, the lowest part of the atmosphere, they are listed below, along with their values according to the International Standard Atmosphere, using for calculation the universal gas constant instead of the air specific constant: Temperature at altitude formula_34 meters above sea level is approximated by the following formula (only valid inside the troposphere, no more than ~18 km above Earth's surface (and lower away from Equator)): The pressure at altitude formula_34 is given by:
Density of air | Troposphere
The surface conductances, formula_23 and formula_24 are approximated by either the Manning or Chezy equation.
HydroGeoSphere | Surface water flow
A 2012 study looked at the imprints made by falling raindrops onto freshly deposited volcanic ash, laid down in the Archean Eon 2,700 Ma in the Ventersdorp Supergroup, South Africa. They linked the terminal velocity of the raindrops directly to the air density of the paleoatmosphere and showed that it had less than twice the density of the modern atmosphere, and likely had similar if not lower density. A similar study in 2016 looked at the size distribution of gas bubbles in basaltic lava flows that solidified at sea level also during the Archean (~2,700 Ma). They found an atmospheric pressure of only 0.23 ± 0.23 bar (23 kPa).
Paleoatmosphere | Density and pressure
The approximate density was obtained using the heavy liquid method, which shows a density of 1.8 g cm.
Canavesite | Composition
The hydrogen exosphere extends to a distance "R"=3.1 "R", much larger than the planetary radius of 1.32 R. At this temperature and distance, the Maxwell–Boltzmann distribution of particle velocities gives rise to a significant 'tail' of atoms moving at speeds greater than the escape velocity. The planet is estimated to be losing about 100–500 million (1–5×10) kg of hydrogen per second. Analysis of the starlight passing through the envelope shows that the heavier carbon and oxygen atoms are being blown from the planet by the extreme "hydrodynamic drag" created by its evaporating hydrogen atmosphere. The hydrogen tail streaming from the planet is approximately 200,000 kilometres long, which is roughly equivalent to its diameter.
HD 209458 b | Exosphere
The remaining elemental composition is roughly typical of the "rocky" inner planets, which formed in the thermal zone where solar heat drove volatile compounds into space. The Earth retains oxygen as the second-largest component of its mass (and largest atomic-fraction), mainly from this element being retained in silicate minerals which have a very high melting point and low vapor pressure.
Abundance of the chemical elements | Earth
From the divergence theorem:
Current density | Continuity equation
An especially notable irregular maximum density is that of water, which reaches a density peak at . This has important ramifications in Earth's ecosystem.
Maximum density | Water
This is decreased when the air is humid. The relative concentration of gases remains constant until about .
Atmosphere of Earth | Composition
20. Jones, T. 2020. "They are dimensionally equivalent"
Current density | References
Notes: the concentration of CO and CH vary by season and location. The mean molecular mass of air is 28.97 g/mol. Ozone (O) is not included due to its high variability.
Atmospheric chemistry | Atmospheric composition
The pressure of the atmosphere is maximum at sea level and decreases with altitude. This is because the atmosphere is very nearly in hydrostatic equilibrium so that the pressure is equal to the weight of air above a given point. The change in pressure with altitude can be equated to the density with the hydrostatic equation where: Since temperature in principle also depends on altitude, one needs a second equation to determine the pressure as a function of altitude as discussed in the next section.
Troposphere | Pressure
Considering the phonon density of states (pDOS) formula_1 in the first Brillouin zone, the center mass formula_2 of the atom-projected pDOS formula_3 of an atom A is defined as formula_4 where formula_3 is the contribution of the atom A to formula_1 and formula_7; the total density of states of the solid is formula_1, defined as
Cophonicity | Mathematical formulation
The equations were said to apply to parcels of air moving on horizontal planes. Indeed, when one considers a column of atmosphere, it is seldom the case that the air density is the same all the height up, since temperature and moisture content, hence density, do change with height. Every parcel within such a column moves according to the air properties at its own height. Homogeneous sheets of air may slide one over the other, so long as stable stratification of lighter air on top of heavier air leads to well-separated layers. If some air happens to be heavier/lighter than that in the surroundings, though, vertical motions do occur and modify the horizontal motion in turn.
Balanced flow | Vertical differences of air properties
Water vapor concentration (humidity) varies considerably, especially in the troposphere, and is a major component of weather. Water evaporation is driven by heat from incoming solar radiation, and temperature variations can cause water-saturated air to expunge water in the form of rain, snow, or fog. The heat gained and lost by water through these processes increases turbulence in the lower atmosphere, especially at mesoscale and microscale. The Brewer–Dobson circulation is a theory of large-scale ozone circulation. Concentrations of other trace gases are higher near natural and artificial sources. This includes pollution from human activity (especially agriculture, industry, and transportation), natural gas fields, radon produced by radioactive decay in certain minerals, volcanic gas, emissions from limnic eruptions.
Homosphere | Variations in concentration
There are dozens more reactions possible, but these are the only ones that are fast enough to affect the abundance of NH in dense molecular clouds. Diazenylium thus plays a critical role in the chemistry of many nitrogen-containing molecules. Although the actual electron density in so-called "dense clouds" is quite low, the destruction of NH is governed mostly by dissociative recombination.
Diazenylium | Chemistry
The density of the nucleus is thus:
Nuclear density | Introduction
Substance consisting of dust and gas, is transferred from the periphery to the center due to gravitational interaction with two giant planets that have a mass several times greater than the mass of Jupiter. Thus, the flows are a kind of "pumps" pumping material from the edge of the center, "feeding" star. The planets themselves have not been detected so far, due to a dense shroud of gas. However, astronomers proposed models that describe their existence. Also Japanese astronomers have discovered particles of ice in the disk.
HD 142527 | Protoplanetary disk
A fluid bulk density formula_9 of 1 g/cm³ is appropriate where the water is fresh but highly saline water has a slightly higher density and lower values should be used for hydrocarbon reservoirs, depending on the hydrocarbon density and residual saturation.
Density logging | Inferring porosity from bulk density
In compounds such as chlorophyll and phenol, some diagrams show a dotted or dashed line to represent the delocalization of areas where the electron density is higher next to the single bonds. Conjugated systems can sometimes represent regions where electromagnetic radiation is absorbed at different wavelengths resulting in compounds appearing coloured. In polymers, these areas are known as chromophores. In quantum chemical calculations, the electron density, ρ(r), is a function of the coordinates r, defined so ρ(r)dr is the number of electrons in a small volume dr. For closed-shell molecules, formula_32 can be written in terms of a sum of products of basis functions, φ: where P is the density matrix.
Electron density | Overview
The flow in many fluids varies with density and depends upon the gravity. Due to which the fluid with lower density is always above the fluid with higher density. Stratified flows are very common such as the Earth's ocean and its atmosphere.
Stratified flows | Introduction
The density of substances varies with temperature and pressure so that it is necessary to specify the temperatures and pressures at which the densities or masses were determined. It is nearly always the case that measurements are made at nominally 1 atmosphere (101.325 kPa ignoring the variations caused by changing weather patterns) but as relative density usually refers to highly incompressible aqueous solutions or other incompressible substances (such as petroleum products) variations in density caused by pressure are usually neglected at least where apparent relative density is being measured. For true ("in vacuo") relative density calculations air pressure must be considered (see below).
Relative density | Temperature dependence
Water vapor and dry air density calculations at 0 °C:
Water vapor | Calculations
For most elements formula_5 is about 1/2 (except for hydrogen where this ratio is 1). The electron density (formula_6) in g/cm³ determines the response of the density tool.
Density logging | History & Principle
Then the spray equation for the evolution of this density function is given by where
Williams spray equation | Mathematical description
Most of tropospheric gases are treated as ideal gases and water vapor, with its ability to change phase from vapor, to liquid, to solid, and back is considered as one of the most important trace components of air. Advanced topics are phase transitions of water, homogeneous and in-homogeneous nucleation, effect of dissolved substances on cloud condensation, role of supersaturation on formation of ice crystals and cloud droplets. Considerations of moist air and cloud theories typically involve various temperatures, such as equivalent potential temperature, wet-bulb and virtual temperatures. Connected areas are energy, momentum, and mass transfer, turbulence interaction between air particles in clouds, convection, dynamics of tropical cyclones, and large scale dynamics of the atmosphere.
Atmospheric thermodynamics | Overview
This is less dense than the average for the interstellar medium in the Milky Way (), though six times denser than the gas in the hot, low-density Local Bubble () which surrounds the local cloud. In comparison, Earth's atmosphere at the edge of space has around 1.2 molecules per cubic centimeter, dropping to around 50 million (5.0) at . The cloud is flowing outwards from the Scorpius–Centaurus Association, a stellar association that is a star-forming region.
Local Interstellar Cloud | Structure
(Ritzer, 2007)
Dynamic density | Context
HydroGeoSphere assumes that the subsurface flow equation in a porous medium is always solved during a simulation, either for fully saturated or variably saturated flow conditions. The subsurface flow equation can be expanded to incorporate discrete fractures, a second interacting porous continuum, wells, tile drains and surface flow. The following assumptions are made for subsurface flow: The Richards’ equation is used to describe three-dimensional transient subsurface flow in a variably saturated porous medium: The fluid flux, formula_2, is represented by the Darcy's law shown as:
HydroGeoSphere | Groundwater Flow
Solute flow is driven by a difference in hydraulic pressure created from the unloading of solutes in the sink tissues. That is, as solutes are off-loaded into sink cells (by active or passive transport), the density of the phloem liquid decreases locally, creating a pressure gradient.
Mass flow (life sciences) | Phloem
The density of air or atmospheric density, denoted "ρ" (Greek: rho), is the mass per unit volume of Earth's atmosphere. Air density, like air pressure, decreases with increasing altitude. It also changes with variation in atmospheric pressure, temperature and humidity. At 1013.25 hPa (abs) and 15°C, air has a density of approximately 1.225 kg/m³ (or 0.00237 slug/ft³), about 1/1000th that of water) according to ISA (International Standard Atmosphere). Air density is a property used in many branches of science, engineering, and industry, including aeronautics; gravimetric analysis; the air-conditioning industry; atmospheric research and meteorology; agricultural engineering (modeling and tracking of Soil-Vegetation-Atmosphere-Transfer (SVAT) models); and the engineering community that deals with compressed air.
Density of air | Introduction
The orthobaric density of a compound is the density of coexisting phases (liquid, gas, or solid) at a given temperature.
Orthobaric density | Introduction
The result is a circulation of the atmosphere that transports warm air poleward from the tropics and cold air equatorward from the poles. The effect of the three cells is the tendency to even out the heat and moisture in the Earth's atmosphere around the planet.
Troposphere | Three-cell model
Substances with a relative density of 1 are neutrally buoyant, those with RD greater than one are denser than water, and so (ignoring surface tension effects) will sink in it, and those with an RD of less than one are less dense than water, and so will float. Example: Helium gas has a density of 0.164 g/L; it is 0.139 times as dense as air, which has a density of 1.18 g/L.
Relative density | Examples
Unexpectedly, three lines were detected in 1998 by McCall "et al." in the diffuse cloud sightline of Cyg OB2 No. 12. Before 1998, the density of H was thought to be too low to produce a detectable amount of . McCall detected a temperature of ~ and a column density of ~10/cm, the same column density as Geballe & Oka. Since then, has been detected in many other diffuse cloud sightlines, such as GCS 3-2, GC IRS 3, and ζ Persei.
Trihydrogen cation | Diffuse interstellar clouds
The upper atmosphere continuously leaks into outer space due to the weak gravity of Triton. The loss rate is about 1 nitrogen molecules per second, which equals about 0.3 kg/s.
Atmosphere of Triton | Structure
The density at all points of a homogeneous object equals its total mass divided by its total volume. The mass is normally measured with a scale or balance; the volume may be measured directly (from the geometry of the object) or by the displacement of a fluid. To determine the density of a liquid or a gas, a hydrometer, a dasymeter or a Coriolis flow meter may be used, respectively. Similarly, hydrostatic weighing uses the displacement of water due to a submerged object to determine the density of the object.
Density | Homogeneous materials
As the temperature varies with height inside the troposphere by less than 25%, formula_45 and one may approximate: Thus: Which is identical to the isothermal solution, except that H, the height scale of the exponential fall for density (as well as for number density n), is not equal to RT/g M as one would expect for an isothermal atmosphere, but rather:
Density of air | Exponential approximation
In three-dimensional Euclidean space, the densest packing of equal spheres is achieved by a family of structures called close-packed structures. One method for generating such a structure is as follows. Consider a plane with a compact arrangement of spheres on it. Call it A. For any three neighbouring spheres, a fourth sphere can be placed on top in the hollow between the three bottom spheres. If we do this for half of the holes in a second plane above the first, we create a new compact layer. There are two possible choices for doing this, call them B and C.
Sphere packing | Dense packing
Three-dimensional transport of solutes is described by the modified reactive transport advective-dispersion equation: formula_25 where formula_26 is the solute concentration, formula_27 is the first-order decay constant, formula_28 is the external source or sink term, formula_29 is the internal solute transfer between domains, formula_30 is the retardation factor, formula_31 is the diffusion coefficient, and formula_32 designates parent species for the case of a decay chain.
HydroGeoSphere | Solute transport
On Earth, physical and chemical differentiation processes led to a crustal density of approximately 2700 kg/m compared to the 3400 kg/m density of the compositionally different mantle just below, and the average density of the planet as a whole is 5515 kg/m.
Planetary differentiation | Density differences on Earth
In contrast, the density of the man-made near-Earth object 6Q0B44E is 15 kg/m.
2009 BD | Physical characteristics
Dividing both sides by formula_14, while formula_15, we have for 1 dimensional linear flow in a porous medium the relation In three dimensions, the equation can be written as
Fluid flow through porous media | Mass conservation
As defined earlier, an incompressible (isochoric) flow is the one in which This is equivalent to saying that i.e. the material derivative of the density is zero. Thus if we follow a material element, its mass density remains constant. Note that the material derivative consists of two terms. The first term formula_15 describes how the density of the material element changes with time. This term is also known as the "unsteady term". The second term, formula_16 describes the changes in the density as the material element moves from one point to another. This is the "advection term" (convection term for scalar field).
Incompressible flow | Difference from material
Density stratification has significant effect on diffusion in fluids. For example, smoke which is coming from a chimney diffuses turbulently if the earth atmosphere is not stably stratified. When the lower air is in stable condition, as in morning or early evening, the smoke comes out and become flat into a long, thin layer. Strong stratification, or inversions as they are called sometimes, restrict contaminants to the lower regions of the earth atmosphere, and cause many of our current air-pollution problems.
Stratified flows | Effects of stratification on diffusion
A zonal flow regime is the meteorological term meaning that the general flow pattern is west to east along the Earth's latitude lines, with weak shortwaves embedded in the flow. The use of the word "zone" refers to the flow being along the Earth's latitudinal "zones". This pattern can buckle and thus become a meridional flow.
Troposphere | Zonal flow
Another discovery about exoplanets' composition is that about the gap or rarity observed for planets between 1.5 and 2.0 Earth-radii, which is explained by a bimodal formation of planets (rocky Super-Earths below 1.75 and sub-Neptunes with thick gas envelopes being above such radii).
Super-Earth | Density and bulk composition
If we consider a line source and a line sink at a distance d we can reuse the results above and the stream function will be The last approximation is to the first order in d. Given It remains The velocity is then And the potential instead
Elementary flow | Two Dimensional doublet or dipole line source
For the simplified model shown the new density is given by: formula_12, where formula_13 is the height of the mountain and c the thickness of the crust.
Isostasy | Pratt
Other factors contributing to density variations in the heterosphere include day and night cycles, solar activity, geomagnetic activity, and seasonal cycles. The heterosphere contains less than 0.001% of the Earth's atmosphere's total mass.
Heterosphere | Earth's Heterosphere
The atmosphere's density depends upon altitude. As an airship rises in the atmosphere, its buoyancy decreases as the density of the surrounding air decreases. In contrast, as a submarine expels water from its buoyancy tanks, it rises because its volume is constant (the volume of water it displaces if it is fully submerged) while its mass is decreased.
Buoyancy | Fluids and objects
Areal surface water flow is represented in HydroGeoSphere by a two-dimensional depth-averaged flow equation, which is the diffusion-wave approximation of the Saint Venant equation for surface water flow. HydroGeoSphere's surface water flow component is implemented with the following assumptions: The surface flow components are solved by the following three equations, which are given by the following mass balance equation: coupled with the momentum equations, neglecting inertia terms, for the x-direction: and for the y-direction: where formula_16 is the surface flow domain porosity, formula_17 is the water surface elevation, formula_18 and formula_19 are the vertically averaged flow velocities in the x and y directions, formula_20 is the depth of surface water flow, formula_21 is the internal fluid exchange, and formula_22 is the external fluid exchange.
HydroGeoSphere | Surface water flow
At 800 atmospheres of pressure the surface atmosphere, with its load of dissolved oxygen and sulphur oxides, is compressed to a density a little less than the density of liquid water (1182 kilograms per cubic meter). Only when the density of the planet's air is a little less than the density of liquid water will the raindrops descend slowly; otherwise, they would come down like meteors and make life on Tenebra impossible.
Close to Critical | Setting
Here "a", "b" and "c" are lattice constants in picometers, No is space group number and "Z" is the number of formula units per unit cell; "fcc" stands for the face-centered cubic symmetry. Density was not measured directly but calculated from the lattice parameters.
Protactinium | Chemical compounds
Thus, the lowest part of the troposphere (i.e. Earth's surface) is typically the warmest section of the troposphere. This promotes vertical mixing (hence, the origin of its name in the Greek word τρόπος, "tropos", meaning "turn"). The troposphere contains roughly 80% of the mass of Earth's atmosphere. The troposphere is denser than all its overlying atmospheric layers because a larger atmospheric weight sits on top of the troposphere and causes it to be most severely compressed. Fifty percent of the total mass of the atmosphere is located in the lower of the troposphere. Nearly all atmospheric water vapor or moisture is found in the troposphere, so it is the layer where most of Earth's weather takes place.
Atmosphere of Earth | Troposphere
In 2017, it was predicted that HD 219134 b and HD 219134 c likely have atmospheres that are secondary in nature, based on the compositions of the planets and the potential for atmospheric escape. For HD 219134 b, the predicted atmosphere was calculated to reach a height of about 0.18 (~1,150 km), below the predicted height of a primordial hydrogen atmosphere (0.28 ). This would indicate a secondary atmosphere produced by processes like volcanic activity and evaporation of volatile materials. However, the composition of volatile materials on HD 219134 b and c could not be accurately determined, yet it is believed that the former has a very thin gaseous envelope, far thinner than those of Uranus and Neptune.
HD 219134 b | Atmosphere
The density of a gas is calculated using the ideal gas law and an equation of state calculation such as the one described in AGA Report No. 8.
Flow conditions | Gas density
The homosphere is the layer of an atmosphere where the bulk gases are homogeneously mixed due to turbulent mixing or eddy diffusion. The bulk composition of the air is mostly uniform so the concentrations of molecules are the same throughout the homosphere. The top of the homosphere is called the homopause, also known as the turbopause. Above the homopause is the heterosphere, where diffusion is faster than mixing, and heavy gases decrease in density with altitude more rapidly than lighter gases. Some of the processes driving this uniformity include heating convection and air flow patterns. In the troposphere, rising warm air replaces higher cooler air which mix gases vertically.
Homosphere | Introduction
In addition, the density of TRAPPIST-1d indicates a mainly rocky composition, with about ≤5% of its mass in the form of a volatile layer. The volatile layer of TRAPPIST-1d may consist of atmosphere, ocean, and/or ice layers. TRAPPIST-1d has an equilibrium temperature of , assuming an albedo of 0. For an Earth-like albedo of 0.3, the planet's equilibrium temperature is around , very similar to Earth's at .
TRAPPIST-1d | Radius, mass, and temperature
The density log measures the bulk density of a formation by bombarding it with a radioactive source and measuring the resulting gamma ray count after the effects of Compton Scattering and Photoelectric absorption. This bulk density can then be used to determine porosity.
Well logging | Density
The number of particles able to escape depends on the molecular concentration at the exobase, which is limited by diffusion through the thermosphere. Three factors strongly contribute to the relative importance of Jeans escape: mass of the molecule, escape velocity of the planet, and heating of the upper atmosphere by radiation from the parent star. Heavier molecules are less likely to escape because they move slower than lighter molecules at the same temperature. This is why hydrogen escapes from an atmosphere more easily than carbon dioxide. Second, a planet with a larger mass tends to have more gravity, so the escape velocity tends to be greater, and fewer particles will gain the energy required to escape.
Atmospheric escape | Jeans escape
The total transport rate of the species is then given by a summation of the Stefan flow and diffusive contributions. An example of the Stefan flow occurs when a droplet of liquid evaporates in air. In this case, the vapor/air mixture surrounding the droplet is the flowing fluid, and liquid/vapor boundary of the droplet is the interface. As heat is absorbed by the droplet from the environment, some of the liquid evaporates into vapor at the surface of the droplet, and flows away from the droplet as it is displaced by additional vapor evaporating from the droplet. This process causes the flowing medium to move away from the droplet at some mean speed that is dependent on the evaporation rate and other factors such as droplet size and composition.
Stefan flow | Introduction
Williamson and Adams assumed that deeper rock is compressed adiabatically (without releasing heat) and derived the Adams–Williamson equation, which determines the density profile from measured densities and elastic properties of rocks. They measured some of these properties using a 500-ton hydraulic press that applied pressures of up to 1.2 gigapascals (GPa). They concluded that the Earth's mantle had a different composition than the crust, perhaps ferromagnesian silicates, and the core was some combination of iron and nickel. They estimated the pressure and density at the center to be 320 GPa and 10,700 kg/m, not far off the current estimates of 360 GPa and 13,000 kg/m.
Mineral physics | History
The density parameter formula_35 is defined as the ratio of the actual (or observed) density formula_1 to the critical density formula_37 of the Friedmann universe. The relation between the actual density and the critical density determines the overall geometry of the universe; when they are equal, the geometry of the universe is flat (Euclidean). In earlier models, which did not include a cosmological constant term, critical density was initially defined as the watershed point between an expanding and a contracting Universe. To date, the critical density is estimated to be approximately five atoms (of monatomic hydrogen) per cubic metre, whereas the average density of ordinary matter in the Universe is believed to be 0.2–0.25 atoms per cubic metre.
Friedmann equations | Density parameter
This roughly translates into needing around ten thousand times atmospheric pressure to reduce the volume of a substance by one percent. (Although the pressures needed may be around a thousand times smaller for sandy soil and some clays.) A one percent expansion of volume typically requires a temperature increase on the order of thousands of degrees Celsius. In contrast, the density of gases is strongly affected by pressure. The density of an ideal gas is
Density | Changes of density
Except where noted otherwise, data relate to standard ambient temperature and pressure. A.F. Trotman-Dickenson, (ed.) in Comprehensive Inorganic Chemistry, Pergamon, Oxford, UK, 1973.
Lutetium(III) oxide (data page) | References
Convective processes of the troposphere affect the transport of water vapour-a green house gas, and its circulation in both the stratosphere and mesosphere. By analysing the processes that occur in these layers, can improve atmospheric models, and provide a better understanding of Earth's climate and weather. The experiment also studies how much water the cloud turrets can carry into the stratosphere, and how lightning influences their formation. Thor analyses red sprites, blue and gigantic jets from the Space Station over Earth at night. Sprites appear as luminous reddish-orange flashes and last 20 milliseconds at most. They often occur in clusters within atmosphere above the troposphere at an altitude range of 50–90 km (31–56 mi).
Thor experiment | Details
In general, higher δD values are observed in humid regions with a high temperature. Water vapor in the atmosphere is in general more depleted than the terrestrial water sources, since the rate of evaporation for HO is faster than HDO due to a higher vapor pressure. On the other hand, the rain water (precipitation) is in general more enriched than the atmospheric water vapor.
Hydrogen isotope biogeochemistry | Atmosphere
formula_1 where σ is the velocity dispersion and G is the gravitational constant. The SIS profile is unphysical because of the singularity at zero radius and the fact that the total mass calculated by integrating the function out to infinite radius does not converge (i.e., is infinite). However, it is commonly utilized in the literature due to the simplicity of its form.
Singular isothermal sphere profile | Density distribution
A typical raindrop is about 2 mm in diameter, a typical cloud droplet is on the order of 0.02 mm, and a typical cloud condensation nucleus (aerosol) is on the order of 0.0001 mm or 0.1 µm or greater in diameter. The number of cloud condensation nuclei in the air can be measured and ranges between around 100 to 1000 per cubic centimetre. The total mass of CCNs injected into the atmosphere has been estimated at 2x10 kg over a year's time. There are many different types of atmospheric particulates that can act as CCN. The particles may be composed of dust or clay, soot or black carbon from grassland or forest fires, sea salt from ocean wave spray, soot from factory smokestacks or internal combustion engines, sulfate from volcanic activity, phytoplankton or the oxidation of sulfur dioxide and secondary organic matter formed by the oxidation of volatile organic compounds.
Cloud condensation nuclei | Size, abundance, and composition
Writing, performance and production credits are adapted from the album liner notes.
300 Percent Density | Credits
Pressure changes the rigidity of the mass flow tube. Pressure affects the rigidity of gravimetric meters.
Density meter | Pressure
Planetary scientists can use calculations of density to determine the composition of planets and their potential to possess liquid water, though the method is not highly accurate as the combination of many compounds and states can produce similar densities. Models of Saturn's moon Titan density indicate the presence of a subsurface ocean layer. Similar density estimations are strong indicators of an subsurface ocean on Enceladus. Initial analysis of 55 Cancri e's low density indicated that it consisted 30% supercritical fluid which Diana Valencia of the Massachusetts Institute of Technology proposed could be in the form of salty supercritical water, though follow-up analysis of its transit failed to detect traces of either water or hydrogen.
Extraterrestrial liquid water | Density calculation
The density (3.62 g/cm) is again intermediate between those of strontium (2.36 g/cm) and radium (≈5 g/cm).
Barium | Physical properties
The higher data density is achieved by using more exhaustive compression techniques. The method is based on iterating entropy modeling and a shortest path search algorithm to find a low bit cost path through the graph of all possible DEFLATE representations of the uncompressed data.
Zopfli | Technology
TRAPPIST-1g has roughly 115% the mass and radius of Earth, though its density is only 4.186 g/cm, about 76% of Earth's. Based on mass-radius calculations and its distant location relative to its host star, and the fact that the planet only receives 25% of the stellar flux that Earth does, the planet is likely covered by a thick ice envelope if an atmosphere does not exist.
TRAPPIST-1g | Mass, radius, and temperature
The high electron density may be in part caused by the low concentration of hydrocarbons in the stratosphere. One of the sources of information about the ionosphere and thermosphere comes from ground-based measurements of the intense mid-infrared (3–4 μm) emissions of the trihydrogen cation (). The total emitted power is 1–2 W—an order of magnitude higher than that the near-infrared hydrogen quadrupole emissions. Trihydrogen cation functions as one of main coolers of the ionosphere.
Atmosphere of Uranus | Thermosphere and ionosphere
In March 2010, transit observations using HI Lyman-alpha found that this planet is evaporating at a rate of 1-100 gigagrams per second. This indication was found by detecting the extended exosphere of atomic hydrogen. HD 189733 b is the second planet after HD 209458 b for which atmospheric evaporation has been detected.
HD 189733 b | Evaporation
As quoted from various sources in an online version of:
Densities of the elements (data page) | CRC
Consider a plane disk of infinite radius rotating at a constant angular velocity formula_1 in fluid which is initially rest everywhere. The outward radial motion of the fluid near the disk due to the centrifugal force must be accompanied by an inward axial motion of the fluid towards the disk to conserve mass. Theodore von Kármán noticed that the governing equations and the boundary conditions allow a solution such that formula_2 and formula_3 are functions of formula_4 only, where formula_5 are the velocity components in cylindrical formula_6 coordinate with formula_7 being the axis of rotation and formula_8 represents the plane disk.
Von Kármán swirling flow | Flow description
Incompressible flow implies that the density remains constant within a parcel of fluid that moves with the flow velocity.
Incompressible flow | Introduction