Questions tagged [atmosphere-modelling]
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Shouldn't the permanent snow line be considerably higher in the Alps and on Mt Hood if temperature falls 6.5°C per 1000 meters?
The permanent snow line in the Alps is around 10,000 ft (3,000 m) elevation. This was further confirmed by a passenger flight I took late June where the screen showed 0°C (freeze point) around 10,000 ...
user29677
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How to explain "Vacuum Cleaner Effect" for upper level PV anomaly?
In Jonathan Martin's Book "Mid-Latitude Atmospheric Dynamics" there is a chapter dedicated to anomalies of potential vorticity (PV). The scenario shown in the image below depicts a situation,...
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How to use CMIP6 to predict windspeed in the future?
I'm very new to climate modelling and forecasting, I have chosen a project to forecast wind energy output in the future using wind speed prediction, I wish to use CMIP6 to predict. But I have very ...
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Estimate EPW AMY parameters from HRRR Analysis
I am working to create Energy Plus Weather (EPW) Actual Meteorological Year (AMY) files from NOAA HRRR Model analysis. The provided links detail the 35 parameters required for the AMY model and ...
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Why positive PV Anomaly moves westwards?
In Jonathan Martin's Book "Mid-Latitude Atmospheric Dynamics" there is a chapter about PV anomalies. As an example, a positive PV anomaly is discussed.
What is the reason, that high PV is ...
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What is the deeper difference between QG Omega equation and QG Height tendency equation?
The quasi-geostrophic $\omega$-Equation
is a diagnostic equation for $\omega$ (=dp/dt = vertical motion) in terms of geopotential. It is derived in a few steps by manipulating vorticity and ...
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Comparing expressions for Ertel Potential Vorticity and Quasi Geostrophic Potential Vorticity
In Meteorology there is a quantity called "Ertel Potential Vorticity" $q_e$ which is conserved considering isentropic flow ($\theta=const)$:
$$\frac{d}{dt}\left(\frac{1}{\rho} \vec \eta \...
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Setting specific humidity vertical profile in an LES
I am working with an LES (Large-Eddy Simulation) model, and I want to define the vertical profile of specific humidity (qt) based on a given temperature profile (thl). However, I am not sure how to ...
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Why is one term missing in the derivation of continuity equation in isentropic coordinates?
In the book by Jonathan E. Martin "Mid-Latitude Atmospheric Dynamics - A First Course"
the continuity equation for isentropic coordinates is derived by applying conservation of mass:
$\...
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Why is mixing ratio at LCL not the same as for starting condition?
I asked a question regarding mixing ratio and wet adiabatic lifting in
https://stackoverflow.com/questions/76244447/why-is-mixing-ratio-at-lcl-not-the-same-as-for-starting-condition.
I don't want to ...
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Is equivalent potential temperature constant also for dry adiabatic processes?
Equivalent Potential Temperature, defined as
$$\theta_e = \theta \cdot e^{qL/c_pT}$$
with $\theta$ denoting potential temperature and q the specific moisture of water remains constant for wet ...
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Why atmospheric temperature lapse rate doesn't have a discontinuity at 0°C when ice is formed?
When trying to calculate the adiabatic lapse rate of moist air based on known values of basic thermodynamic properties of the constituents (ice, water, vapor,...) I came to the following question:
...
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Why is latent heat of water vapor included in specific enthalpy of moist air?
In a lecture book we read about latent heat of moist air.
I would have guessed, that the total specific enthalpy of moist air, comprised of $m_d$ kg of dry air and $m_v$ kg of water vapor is (we have ...
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Which way is the more computationally efficient for running WRF-Chem with one way nesting: (a) by setting feedback to '0' or (b) using ndown.exe?
I want to run WRF-Chem with one-way nesting because of the limitations of my system (a linux server with 378 GB of RAM and 32 processors). I have gone through the WRF user guide, which explained how ...
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Do I understand pressure coordinates in the right way?
The question is simple: I still have problems with atmospheric pressure coordinates:
Given the pressure dependence in the picture, what are the velocity coordinates of an air parcel moving with $\vec ...
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How is Wind oriented in a Jet Streak?
Recently I found this tutorial video about Jet streaks (want to mention I'm only in second term so my knowledge is not advanced yet). Originally I was looking for the topic because of a particular ...
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How to estimate altitude of tropopause of other planets?
Is it possible to come up with a formula to estimate the height of the tropopause and the upper layer lapse rate only based on atmospheric composition and other atmospheric parameters (not relying on ...
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Why are there different Notations of Vorticity Equation?
I'm a student of meteorology in first year. This time my question is not about a particular problem I have, but rather about teaching and learning: In a recent lecture on atmospheric dynamics we ...
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Moist adiabatic lapse rate
I asked this question in the Physics SE but it still lies unanswered. Hopefully Earth Science SE is more knowledgeable in the matter.
Wikipedia gives the following equation to calculate the moist ...
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Why air parcel is on a circular trajectory when considering Coriolis force
According to Coriolis force an air parcel is deflected in the absence of other forces by the acceleration (Holton, 4th Edition):
These equations lead to circular motion.
This figure is from a Matlab ...
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How can speed of geostrophic wind change when forces are always perpendicular to speed?
Equation for acceleration of an air parcel is
$$D \vec U/Dt = -2 \vec \omega \times \vec U -\frac{1}{\rho} \vec \nabla p + \vec g$$
Now, for geostrophic wind, U is parallel to the contour lines of ...
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What does the index "p" mean in the gradient of geopotential in pressure coordinates?
Currently I hear a series of tutorial videos on atmospheric dynamics as a first starting preparation for reading more detailed material, such as Holton. In particular I refer to this part:
https://www....
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Book on atmosphere dynamics
I plan to study a good introductory book on atmospheric dynamics:
which one is more recommended? My background is a university degree in physics, but I'm new to meteorology.
An Introduction to
...
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What is the atmospheric pressure at the deepest point of the Kidd mine?
At 2735 m (8973 ft) below sea level, the Kidd mine reportedly has the deepest non-marine point of the Earth's surface (since the Kola borehole is sealed). I wonder what the pressure down there is, as ...
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Why is the quantity "Geopotential" important in meteorology?
So far I understood, geopotential $\Phi$ is just defined by
$$\vec \nabla \phi = \vec g$$
But because g can be taken to be constant within troposphere, it is nothing but
$$\Phi(z) = g \cdot z + C$$
So ...
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How is centrifugal force identified in equations of fluid motion in the rotating reference system of earth?
I spent already days on the following: In one of my meteorology scripts the equations for conservation of momentum in the rotation reference system of earth are given by:
The apparent forces are in ...
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Which atmosphere model(s) put the upper end of the tropopause isothermal layer at 25 km and why?
The International and U.S. Standard atmospheres have a layer between 11 km (36,000 ft) and 20 km (66,000 ft) where the temperature is constant with altitude. This includes older versions of the U.S. ...
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divergence of static stability identical parameters
All,
The static stability of the atmosphere is defined as:
$\sigma =-\dfrac{T}{\theta} \dfrac{d\theta}{dp}= \dfrac{dT}{dp}-\dfrac{R}{c_p} \dfrac{T}{p}$
where:
$T$ is temperature,
$P$ is pressure,
$R$ ...
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Where does this refractive index formula come from: $n_{1} = n - 1 = \frac{77.6P}{T} 10^{-6}$
In this equation, $n_{1} = n - 1 = \frac{77.6P}{T} \cdot 10^{-6}$ the variable P is the total air pressure and T is expressed in Kelvin. This equation describes the refractive index of moist air as EM ...
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What does the refractive index static coefficient measure and how is it derived?
From my understanding the refractive index structure coefficient $C_{n}^2$ measures atmospheric turbulence, but I'm not entirely sure as the literature seems to imply that there are slightly different ...
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Python, R or etc.? [closed]
I was wondering which programming language is most used in the geosciences? I have now started programming with Python but I am reading more and more about R! I would like to ask the experienced ...
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Estimating meteorological visibility from air chemical and particulate composition
I have found here an answer that provides formula that only takes into account vapors, pressure and temperature - What is the formula used for atmospheric visibility?
Is there an approach that also ...
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Clarification of dry deposition of particles
I found a formula for the dry deposition speed of particles and an electric circuit analogy to go with it. I would like some clarification on this figure:
I'm mostly interested in the top right ...
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A problem of the 2-Layer hydrostatic model
The 2-layer hydrostatic model is like this
And the pressure of the two layers and the top are
and it is easy to find the horizontal gradient of $p_1$ and $p_2$
\begin{equation}
\begin{aligned}
\nabla ...
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Why does the Earth's atmosphere appear to no longer follow the curvature beyond the terminator line?
I had noticed this on Google Earth and Celestia already.
Here's an image from the ISS:
As you can see on the horizon, at the terminator the atmosphere doesn't seem to follow the curvature any longer ...
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Retrieve surface values in hybrid sigma cordinate system
I need to retrieve surface values of a parameter in high mountainous region that are in hybrid sigma coordinate system.
From what I have understood, hybrid sigma coordinate has three layers in the ...
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How to convert units of averaging kernel from DU/DU to ppbv/ppbv
For validation of model data, I want to compare the ozone data from model to the satellite results downloaded from the following link:
The satellite data are in DU(Dobson Unit) while the model data ...
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Can historical emissions data be used for a future WRF-Chem model run?
I am new to running the WRF-Chem model, so this question maybe a little elementary. I wanted to perform an year-long simulation of certain chemical species for 2019 and for that, is it sufficient to ...
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Is spin-up really required to run the WRF-Chem model and if so, what determines the time period of the spin-up?
For example, I am interested in making a simulation for some chemical species for 2019. I am planning to provide NCEP/GDAS FNL meteorological data at 0.25 degree and CAM-Chem chemical boundary layer. ...
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Tornado prediction or forecasting by supercomputers [closed]
Can tornadoes be predicted or forecasted using supercomputers?
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What is the atmospheric percentage of oxygen produced by trees and phytoplankton every year?
I know that every year carbon sinks remove ~20Gt of CO2 (about half of our emissions), and release a comparable amount of O2 , But I want to know how much O2 the carbon sinks produce annually ...
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How to convert $\ce{NO2}$ mixing ratio (ppmv) into $\ce{NO2}$ column density(moles/m2)?
I have a WRF-chem output with NO2 mixing ratio for 37 levels, for my analysis I need to convert it into into column density. How do I do that?
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Nobel prize Manabe's 1967 code for solving the 1D atmospheric thermal equilibrium model
Does someone know where to find a (hopefully modern) version of the numerical code for solving the 1D atmospheric thermal equilibrium model, the one Syukuro Manabe & Richard T. Wetherald used in ...
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Would the atmosphere move rigidly with ground if you ignored wind?
I know this sounds basic but I've wondered about this for a long time and I'm still confused.
In aviation, air speed is ground speed minus wind speed. If wind speed is zero, air speed equals ground ...
user22590
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Climate on Venus after it becomes tidally locked
Suppose, Venus becomes tidally locked. Will its dark side cool enough so that the CO2 from atmosphere to precipitate in liquid form to make an ocean?
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Difference in values if the source region lies outside or within the nested grid domain with boundary conditions from coarser resolution
I want to see the anthropogenic influence of one region(source) to another region(receptor). I would be conducting nested grid simulation. But, the nested grid simulation will be limited to receptor ...
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Meaning of ECMWF model levels
I am trying to understand the actual meaning of the ECMWF L137 model levels. In the link I provided, both pressures (in hPa) and heights (in m) are given for every level. But which actually defines ...
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How to derive the total potential energy of the atmosphere?
In one of Lorenz’s paper (I mean the meteorologists Edward Lorenz), he stated that the total potential energy of the whole atmosphere $P + I$ (means the sum of potential energy and internal energy) is
...
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Correct way to spin-up for sensitivity analysis in a Global Chemical Transport Models
In my understanding, in Global Chemical Transport Models, initial conditions are provided by spinning up the model or through previous simulation. But, can I use the same initial condition that I ...
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Free forecast vs cycled model runs
What is the difference between a free forecast and a cycled model run? This GFS wiki mentions both, but does not define them.
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