Questions tagged [numerical-modelling]

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US vs EU weather systems commercialization and precision? [closed]

The US and EU have very different government funding systems for weather and space equipment, perhaps as different as the road systems. The US has a higher performing health system on average at a ...
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1 vote
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23 views

Are there any online earth science formula/equation libraries?

I'm looking for a formula library like fxSolver but specifically for Earth science formulas. I could rummage through scientific papers like a nerd racoon, but first I want to make sure there isn't a ...
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Can we know if a numerical model will converge or not according to the boundary conditions?

Consider a square 2D domain and a steady-state simulation. According to the geology of the domain, the North, South, West and East limits must be conditions of zero flow (Neumann). The aquifer ...
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4 votes
1 answer
95 views

How are boundary conditions considered in PDEs?

I'm new to numerical modeling and trying to figure out how things work inside business codes. Consider a 1D domain divided into small cells of width dx and at the East and West a Neumann conditions ...
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6 votes
2 answers
164 views

How do academics/institutions run large climate simulations given the computing challenges?

I have been brushing up on numerical methods for PDEs lately, and climate models provide such a rich set of models and ideas to practice with. However, I was a little confused about how academics can ...
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1 answer
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Why are all the variables ( DRY_DEP_FLUX and WET_DEP_FLUX) zero in a wrf model output in all the time steps

I am working on WRF_GHG, I would like to calculate dry and wet deposition in the dry and wet seasons for CO2 and CH4 gases. However, when I check the wrf output, I see that all the variables (...
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6 votes
1 answer
101 views

Calculating Love numbers (tidal deformation) for non-homogeneous planets

I have a question about planetology. I'm not sure if it belongs here, but the astronomy stack exchange seemed a bit odd, too. I would like to enhance my understanding of Love numbers. Love numbers ...
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1 vote
0 answers
35 views

ESMF installation error "error: no match for ‘operator==’ "

I need to install ESMF-5.2.0rp3 version. I have downloaded it from https://github.com/esmf-org/esmf/releases/tag/ESMF_5_2_0rp3. Also I installed the following prerequisites: Fortran95, GCC & C++ 7....
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wrf_chemi file with 30 time steps

I creat wrfchemi file for my wrf-chem, my wrfchemi file has 30 time step, frames_per_auxinput5 = 30, 30, auxinput5_inname = "wrfchemi_d", auxinput5_interval_m = 60, 60, ...
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3 votes
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56 views

Is there a modelling of Wave Rock (Hyden Rock) formation?

I'm interested in the visualization of the formation process of "strange" objects like Wave Rock (flared slope). I've found articles describing hypotheses of the rock formation but I cannot ...
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4 votes
2 answers
772 views

How to install ESMF and ESMFPy in Ubuntu using gfortran, gcc, python?

I am trying to regrid some of my latitude-longitude grid files to tripolar ocean grid and found that ESMF can be useful. However, I am finding it hard to install the same.
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1 vote
1 answer
566 views

How to de-stagger (or unstagger) WRF wind fields?

I am trying to calculate wind speed from the U and V wind components of a Weather Research and Forecasting (WRF) simulation. However, I came to realize that some ...
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3 votes
1 answer
207 views

How to convert the units of specific cloud liquid water from ERA5 (kg/kg) to kg/m2?

I am trying to initialize my model with the cloud liquid water data from ERA5. My model IITM-ESM which evolved from CFSv2 takes in the cloud liquid water information in $\small\mathsf{kg/m^2}$. ...
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1 vote
0 answers
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Model relating reservoir releases with downstream temperature

Are there any statistical/numerical models developed relating release from reservoirs with the downstream river temperatures? I know of complicated hydrodynamic models such as CE-QUAL-W2 etc. but I am ...
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2 votes
1 answer
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Discrete distribution of daily rainfall [closed]

How can I estimate the rainfall rate every ten minutes during a day having the total amount of rainfall during that day ?
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4 votes
1 answer
278 views

How to determine the orientation of coastline from NetCDF file

I have a NetCDF file (gridded data) with a landsea mask. I would like to determine, for the coastal grid-cells, what the orientation of the coastline is. I need to do this in order to calculate the ...
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2 votes
3 answers
503 views

Temperature Advection using finite differences with gridded data

Advection of a scalar quantity, such as temperature (T), by the horizontal wind, is defined as follows: $-\textbf{U}\cdot\nabla T$ where $\textbf{U}$ is the horizontal wind vector, $\textbf{U}=(u,v)$...
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0 answers
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How to control output precision when running WRF?

I am very new in this area and wondering if anyone can answer my following questions: I am running WRF (4.0.3, ideal) to study rounding and truncation. I use the NCL (6.5.0) print command to access ...
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1 vote
0 answers
217 views

python generate 3d unstructured grid

I would like to create a 3d unstructured grid based on data points with xyz and property. Can Python do this and what tools? My question is quite generic but i can provide more details: the data has ...
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4 votes
0 answers
24 views

Statistical dependence of mean annual soil evaporation and mean annual precipitation globally

I am studying a simple dynamical system that represents a plant and water system, similar to Klausmeier. In Klausmeier model the mean annual precipitation and the soil evaporation are introduced as ...
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2 votes
1 answer
283 views

Difference between model parameter and observable parameter

In Inverse problem theory, what is meant by "results of the measurements of observable parameter"?
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1 vote
0 answers
87 views

WRF: minimal list of variables required by coupling a land surface model to the whole system

We are trying to couple our land surface model into WRF. As a first step, we'd like to know what is the minimal list of variables required by such coupling?
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4 votes
1 answer
111 views

Simple and realistic data for glacier modeling

I'm programming the nonlinear Stokes problem (with a finite element method), $$\operatorname{div}(\mu(u)\nabla u+pI)=f$$ where $\mu(u)$ is the Glen's power flow law (typical for glaciers). I want to ...
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5 votes
1 answer
126 views

Calculate the number of model grid cells covering a specific country

What is the best method of calculating the number of model grid cells (e.g. of climate models) covering a specific country? For example, if I wanted to know how many 2 degree grid cells are in the ...
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6 votes
1 answer
445 views

How do spectral methods work in the context of numerical weather prediction models?

I am broadly familiar with the concept of numerical weather prediction models using various finite methods to solve the primitive equations used in these models, but how do spectral methods work, ...
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1 vote
1 answer
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Why RBF is gridless and kriging is not?

I read about it somewhere in a paper. Why is kriging not gridless if I can krig points in space? Whats is the big difference from RBF?
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5 votes
2 answers
423 views

correct way to calculate transport through a section in an ocean numerical model

Suppose that I want to calculate the transport across a certain transect (green line) from the outputs of an ocean numerical model. The model has the $u$ values at the center of the grids (crosses) ...
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3 votes
0 answers
63 views

Reasons for choosing LES in stead of RANS models?

In oceanography, is there any particular reason why choosing large eddy simulations in stead of RANS (regardless of the type of flow)? In both cases, 2d simulations would be used (shallow water model)....
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5 votes
0 answers
76 views

What is the equivalent of CFL criterion when using spectral models?

I would like to know what the equivalent of the CFL criterion is for atmospheric models based of spectral grids. In other words, how do you find the necessary horizontal resolution in meters for ...
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3 votes
0 answers
62 views

Visually Realistic Supercell Modeling

Are there any published descriptions of simple equations governing the formation, evolution, and decay of severe storms? Specifically, I am interested in equations that are able to produce tornadoes ...
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8 votes
3 answers
1k views

Effect of urbanization on weather events

At what stage is the studies on effect of urbanization on weather events (eg: Rainfall, Temperature, UHI) are now? There has been a number of observational and modelling studies around the world and ...
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4 votes
0 answers
63 views

Determining rotation of a bending detachment fault system

I would like to obtain the angle of rotation (𝛿θ) of a detachment fault (or oceanic core complex) after X meters of rock displaced during spreading at a mid-ocean ridge. I have a differential ...
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6 votes
2 answers
86 views

Does hydroxyl radical chemistry in air quality models create numerical stability problems?

Atmospheric mixing ratios of the hydroxyl radical have relatively short lifespans (on the order of microseconds). When modeling air quality or the weather, the time step is usually much larger than ...
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7 votes
1 answer
813 views

Computing Isentropic Potential Vorticity from Hybrid Sigma Pressure levels

My task is to compute isentropic potential vorticity on a grid. All data (ECMWF ens) are given on a hybrid sigma pressure grid. Since I really cannot find reference, I assume (!) that relative ...
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2 votes
2 answers
54 views

Which equations describe complete (or near complete) behaviour of magma moving through rocks?

Yes this is a bit broader question but I want to know which processes play their role in movement of magma. If one wants to model magma movement through rocks, which processes should one not miss at ...
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3 votes
0 answers
60 views

Formula for numerical model for sustained warming in marine sediment?

I have been reading this paper and found simple numerical formulations to model the time duration, affected depth and amount of warming of marine sediments. The author uses a rudimentary estimate of ...
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9 votes
1 answer
203 views

Why should dynamical downscaling of meteorological data be made incrementally?

When downscaling meteorological data by using limited area models, many support forums recommended you to downscale incrementally in small steps. For example let's assume that your input data is on a ...
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2 votes
1 answer
2k views

How to set up a domain from namelist in WRF?

I'm fairly inexperienced with WRF and was wondering if anyone could point me in the direction of any helpful resources for it. The task I have is to make a simple 9 km domain, but I'm having trouble ...
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7 votes
1 answer
375 views

What's the prospect of air quality forecasting based on machine learning?

Air quality forecasting models which are useful for atmospheric scientist and government can be built based on numerical theory or statistic theory. The first approach outline the basic physics ...
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2 votes
0 answers
103 views

Numerical methods for solving shallow-water equations with a source

What are the numerical methods used for solving shallow water equations (PDEs) with a mass source, at the synoptic scales of the atmosphere, if I have a finite east-west boundary (may be periodic wave ...
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4 votes
0 answers
79 views

Unwanted oscillations in Synthetic seismogram

I have generated a synthetic seismogram using FDTD elastic velocity-stress formulation on a staggered grid. I can't understand origin of oscillations modulating on seismogram. Is it a result of ...
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2 votes
0 answers
320 views

What is difference between Riverbed conductance term and streambed leakance/retardation coefficient?

In literature some times to account for semi-pervious sediments at bottom of stream, streambed leakance also called retardation coefficient ($L$) is used. This is equal to the ratio of conductivity of ...
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8 votes
3 answers
882 views

What exactly is a model grid?

I have just begun reading some notes about modelling and can't seem to understand what a 1°x1° grid or a 2.5° grid or 1/4° grid is. I know it is something related to the resolution of the area over ...
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9 votes
0 answers
203 views

Modeling swirling storms

I'm looking to demonstrate the rotational behaviour of swirling storms with a numerical simulation. So far it includes pressure-gradient, Coriolis acceleration, frictional forces and the acceleration ...
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8 votes
1 answer
167 views

Unrealistic solution for advection-diffusion-reaction PDE with heterogeneous porous media

About the code: I have a code which simulates concentration from advection-diffusion-reaction PDE in 2D space (X,Y) with time. The solution is obtained using fully implicit finite-difference method ...
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10 votes
1 answer
453 views

Optimal vertical coordinate for complex topography

There are plenty of choices in models in so far as choice of vertical coordinate is concerned for meteorological models. Five that I know of: The sigma coordinate system - Hybrid coordinate system(...
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10 votes
2 answers
399 views

The origin of spurious high frequency waves in numerical weather prediction

I am currently reading this paper on digital filters and their relevance to meteorological models Digital Filter Initialization . My question relates to this following text - "The requirement to ...
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5 votes
1 answer
410 views

What is "focus point" in WRF-plots grid box? (python code)

has anyone used the python code from here (written by Geir Arne Waagbo) to plot skewT plot from WRF output? I've got a question regarding some of the functions used in the code found in ...
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9 votes
4 answers
284 views

Confusion about grid registration concepts and their relevance in modelling

I'm trying to make use of the ETOPO1 dataset as the bathymetry input of a wave model. I came upon this discussion of grid registration: Registration of Structured Square-Cell Grids. I read this ...
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10 votes
3 answers
5k views

Meaning of Coupling in Modelling

The Community Earth System Model (CESM) is described as a fully-coupled, global climate model that provides state-of-the-art computer simulations of the Earth's past, present, and future climate ...
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