Questions tagged [models]

A tag for questions about conceptual, analytical or numerical models used in Earth science disciplines.

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35
votes
2answers
876 views

Similarities between grand circulation solvers and mantle convection solvers

My impression is that both ocean grand circulation models (e.g. MITgcm), and Mantle Convection models (e.g. CitcomS), both use Navier-Stoke's as the governing equation. What are the other major ...
29
votes
4answers
4k views

How do weather models work?

We use different weather models all the time, such as the ECMWF and the GFS. These models are simply amazing to me. How do these models work? I know they have to take in various data points - what ...
21
votes
7answers
2k views

What tools allow a quick comparison of NetCDF output from ocean models?

I am writing my own MATLAB scripts to do most of the visualization and data analysis of model results. I wonder if there is a quicker way for visual comparison of simulation results gained from ...
21
votes
2answers
305 views

How can I improve the numerical stability of a coastal hydrodynamic model?

I am working with a coastal hydrodynamic model in the MIKE3 modelling package. MIKE3 uses the finite volume method to solve the shallow water equations with explicit timestepping, over a triangular ...
21
votes
1answer
653 views

Significant difference between averaged wind speeds and averaged wind power density, for wind generation modelling?

Climate models outputs, particularly the reanalysis datasets, output wind speeds as zonal and meridional averages for the modelled time period (typically 1, 3 or 6 hours). So we get a 2-dimensional ...
20
votes
2answers
4k views

What are the major differences between weather models and climate models?

Some weather models include GFS (Global Forecast System) and NAM (North American Mesoscale Model). Some climate models include CCSM (Community Climate System Model) and the NASA GISS (Goddard ...
18
votes
2answers
5k views

What are the applications of hydrostatic solvers vs non-hydrostatic solvers in numerical weather prediction?

In the atmospheric dynamics research community, many colleagues of mine happen to use atmospheric models that have non-hydrostatic equation solvers, e.g. the UK MetOffice model, and WRF-ARW: The ...
18
votes
1answer
364 views

How is global weather model skill measured?

The models I have in mind are the major global models such as the Global Forecast System (GFS) and the European Center for Medium range Weather Forecasting (ECMWF). These models produce numerous ...
17
votes
1answer
9k views

What are the differences between an LES-SGS model and a RANS based turbulence model?

I'm kind of new to the Large Eddy Simulation (LES) modeling world and I wondered what is the difference between an LES subgrid scale model like the Smagorinsky–Lilly model and a one-equation Reynolds-...
16
votes
2answers
1k views

Great Pacific Garbage Patch Equilibrium Points

I was watching the science channel yesterday and the program mentioned the Great Pacific Garbage rim. I was struck by the illustration (and pretty much every subsequent animation/picture I've seen now ...
15
votes
2answers
585 views

Will model resolution have an effect on model spin-up time?

In terms of uncoupled AGCM studies, I've seen people use periods within a decade (say, 5 years) as spin-up time, but I also see some people take tens of year as spin-up in some recent studies. So I'm ...
15
votes
0answers
217 views

How to compute the earthquake occurrence probability under ETAS model

I have fitted an ETAS model (unmarked) with an independent exponential magnitude distribution to a set of earthquake data. However, I do not know how to calculate the probability of the earthquake ...
14
votes
2answers
2k views

Software for sediment transport modeling

I am doing a paper about coastal processes and I was told that I should include a sediment transport modeling to further examine my geophysical findings. I was reading in the net and found that ...
14
votes
2answers
692 views

How important is understanding linear algebra in groundwater modeling?

I am considering taking a course in linear algebra and wanted to get a survey to see how important it is. My goal is not just to understand how to push the buttons in some software (e.g. GW Vistas, ...
14
votes
1answer
757 views

What is the force imposed by underwater currents?

I would like to calculate the force of an underwater current on a meter by meter plate (or any other unit that you may use to represent it) that is standing in front of the current. How do I calculate ...
14
votes
1answer
1k views

How can I estimate a 2 m temperature from / in an atmospheric model?

Numerical models of the atmosphere usually have their first atmospheric grid level well above 2 m, but the temperature at 2 m above ground level is something one often wants to calculate with such a ...
13
votes
6answers
363 views

Is there value in using a model that fails at validation against measurements?

Say we have a model that describes a physical or dynamical system, for example, a hydrological model. If the model results do not match the measurements of the quantity being simulated, i.e. the model ...
13
votes
4answers
5k views

How to get cell indices from latitude and longitude in WRF model grids?

I am using Weather Research and Forecasting model WRF and the WRF Preprocessing System WPS and could not get a satisfying answer from wrfhelp. Can anyone guide me in transforming latitude and ...
13
votes
2answers
2k views

What is the difference between a high-resolution model and a regular model run?

So we have high-resolution models like the HRRR (High Resolution Rapid Refresh). But what exactly is the difference between a high-resolution model and a regular model? I realize that the higher ...
13
votes
2answers
136 views

What are the guidelines for constructing variable names that follow CF conventions?

I am attempting to develop variable names following Unidata's climate forecasting (CF) variable naming guidelines, but for biological variables used to parameterize and evaluate land surface and ...
13
votes
2answers
1k views

Model types: Robust diagnostic versus prognostic

I wonder whether someone knows a clear definition/description of 1) Robust diagnostic models Forcing with data from initial state aimed at future predictions? 2) Prognostic models Tie model ...
12
votes
3answers
5k views

What are the differences between implicit and explicit methods when applied to modelling Earth systems?

I am struggling to understand the difference between implicit methods and explicit methods in numerical modelling of Earth processes, particularly when applied to modelling Earth systems in 2 or more ...
12
votes
1answer
2k views

Why is WRF most often configured at 3:1 nesting ratio?

In WRF application, nested domain has always been used for weather/air quality modeling for the place of interest in a better resolution. The figure below illustrates this: I have noticed that the ...
11
votes
3answers
300 views

Does finer input data lead to a better model accuracy?

Climate and chemical transport models all need input files including meteorology data, emission inventory, surface data (e.g. land use type) to initialize the simulation field. Take the case of WRF ...
11
votes
1answer
230 views

Generic pedo-transfer functions to compute field capacity and wilting point from sand/silt/clay?

I have a model (Miguez et al 2008) that defines wilting point as the soil water content below which there is no transpiration (from Johnson et al 1993). Field capacity is defined as the volume of ...
10
votes
3answers
4k 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 ...
10
votes
3answers
592 views

How to run earth system, land surface and climate models?

I am interested in earth system models, land surface models and climate prediction models. I found a lot of online information on different models, including CIMP5, and the Earth System Modeling ...
10
votes
1answer
222 views

Stability correction factor in the Wavewatch III wave model

I'm studying the Wavewatch III wave model (http://polar.ncep.noaa.gov/waves/index2.shtml). I'm confused by the stability correction factor, named ASF in the code. What is its purpose? Is it related to ...
10
votes
1answer
683 views

Resources for learning the technical parts of atmospheric modeling

I'm a computer/atmospheric science undergrad and I'm trying to get into atmospheric modeling. Any recommendations for resources to get going or to learn about approaches? I can handle fairly technical ...
10
votes
1answer
728 views

What tidal databases are available to be used as model boundary conditions?

I am trying to set up a coastal ocean model simulation. I am looking for different ways to force the tidal boundary condition in the model to study how uncertainty in the tidal forcing in the boundary ...
10
votes
1answer
250 views

How to determine the transmissivity of a system of rocks and faults from the stationary drawdown pattern?

I have a dataset containing high frequency measurements of the hydraulic head at different locations in a 5x6km area. Also known are the precipitation, evaporation, and pumped discharges from a number ...
10
votes
2answers
704 views

Technique to delete spin-up frames from WRF

I'm a user of WRF V3.5 aiming at meteorological simulation. Sometimes, I'll run the model for a long period. My attempt I split the long period(e.g 1 year) into serval short ones. For ...
9
votes
5answers
895 views

Correct phrase for a 'forgetful' natural system?

This is a rather general question: assume I have a system that has a certain 'forgetful' property, which means that while I can offset its current state for a moment, it will eventually return to its ...
9
votes
4answers
216 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 ...
9
votes
1answer
197 views

Why can't wave models model storm surge?

I found this nice module here on MetEd that gives an overview of the WAVEWATCH wave model. In it, in the Introduction section, it is mentioned that WAVEWATCH cannot model storm surge or tsunamis. Is ...
9
votes
2answers
692 views

What tools are available to build unstructured grids for ocean models?

Generating finite element/volume grids is tricky, especially when you are dealing with complex coastlines. What are the more common tools to create the grids and to check the quality (e.g., minimum ...
9
votes
1answer
155 views

How should I choose the block size in constrained model-based inversion?

In constrained model based inversion, block size (in ms) is one of the inversion parameters. Specifying the block size value in the software divides the pseudo-velocity log into that number of layers ...
9
votes
1answer
59 views

Lab procedure for analyzing/assessing the presence of semi-volatile solids

I'm looking for a lab experiment design that shows how to measure the presence of semi-volatile solids in water (and not sludge or soil or solids). All I have found so far are chromotography/mass ...
9
votes
0answers
77 views

What field studies have developed or supported the Penman-Monteith equations for estimating evapotranspiration?

I'm trying to understand transpiration estimation methods. The FAO recommends a standard Penman-Monteith methodology for modeling evapotranspiration based on meteorological and vegetation parameters (...
8
votes
3answers
556 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 ...
8
votes
2answers
2k views

What are some options for online and offline particle tracking in ocean models?

I am looking for a few options of particle tracking for ocean modeling to try to do a comparison of different codes.
8
votes
3answers
885 views

Why do deviated wells show poor correlation to seismic data?

Well correlation and calibration is an important step in any type of seismic inversion. In order to obtain a good broadband frequency model, the synthetics should be correlated with original seismic ...
8
votes
2answers
178 views

What determines the differences in results between various weather models?

It's often said that the ECMWF model is more accurate than the GFS. But what are the reasons why? Also, how does the NAM compare with these two and other forecasting models?
8
votes
3answers
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 ...
8
votes
3answers
198 views

Climate change review for a scientist [duplicate]

I am a Ph.D student in Computer Science and Statistical Genetics. I recently became very interested in climate change, for obvious reasons. I would like to use my solid scientific and statistical ...
8
votes
1answer
7k views

Converting grid resolution from degrees to kilometers

I am curious how can one have an idea of grid resolution. How much is the distance resolution in km of a grid with resolution of 0.5 deg x 0.666 deg?
8
votes
1answer
717 views

Are we now and/or have we been in the RCP8.5 scenario?

Is it generally understood that we (globally) have been living in an RCP8.5 scenario over the past 7-8 years? Such that a predictive climate model using RCP8.5 assumptions that was run circa 2011 can ...