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Questions tagged [models]

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

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3
votes
1answer
148 views

High Discharge Value in SWAT modelling

At first run I’ve encountered the problem since the values of modeled and observed discharge are significantly different. The correlation between them is nearly 0,2...
8
votes
3answers
878 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 ...
9
votes
4answers
213 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
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 ...
7
votes
1answer
664 views

WRF output grid is smaller than input definition

I am running some test forecasts using WRF 3.6.1. and am having some problems with my grids. Specifically, I am specifying a parent and nest domain each with 25 points for longitude and latitude (so ...
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 ...
2
votes
0answers
133 views

Problem running the WAM wave model [closed]

In the WAM Cycle 4 wave model, why doesn't the model work for the year 1999? When I tried to run for the year 1999 the model does not produce any results.
3
votes
1answer
142 views

Meaning of “Objectively analyzed”

I've found that there may possibly be many meanings of "objectively analyzed" and "objective analysis" in modeling and data assimilation. What are some of the accepted meanings?
4
votes
1answer
124 views

References for moving and nested grids in models

Would anyone know of references that give detailed explanations on concepts such as moving grids and nested grids in models?
14
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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 ...
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 ...
8
votes
1answer
526 views

What is a Geophysical Model Function (GMF)?

I have heard the term mentioned many times in seminars, and in papers on remote sensing. What does it mean? References would be helpful if available.
4
votes
1answer
1k views

Negative values of relative humidity in CFSR

I recently started using the Climate Forecast System Reanalysis (CFSR) 6-hourly products (http://rda.ucar.edu/datasets/ds093.0/), and I noticed many values of relative humidity are negative. Is this ...
14
votes
2answers
689 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, ...
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 ...
10
votes
1answer
220 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 ...
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-...
10
votes
1answer
677 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 ...
8
votes
3answers
313 views

Understanding the Mercator Projection

To illustrate my problem, let's say I have lattitude and longitude coordinates, such as 38.871105, -77.056042. I want to be able to calculate the new lattitude and longitude if, say, I moved 300m ...
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 ...
21
votes
1answer
651 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 ...
11
votes
1answer
229 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 ...
1
vote
1answer
161 views

Princples of process (systems) based modeling [closed]

What books are available that address the fundamental principles all processed based modelers should be aware of? Is there a guide, some holy grail of text books for process based simulation models?...
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 ...
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 ...
10
votes
1answer
727 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 ...
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
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 ...
15
votes
2answers
582 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 ...
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 ...
7
votes
1answer
743 views

What is “qflux” and why is it important for climate models?

Evaluation of the Ocean Q Flux is an example of qflux used in the CESM model. Why is it important?
8
votes
2answers
176 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?
10
votes
1answer
247 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 ...
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.
5
votes
3answers
2k views

What are the domains of Earth Science?

Increasingly confused by all the "spheres" and agreed relationships between them. As a result, I am looking for a singular answer that clearly states at the very least what the top-level and secondary ...
8
votes
3answers
1k views

A good book or source for climate science and meteorology basics?

I have a mainly a hydro-geological and geo-statistical background, I would like to have a basic introduction to meteorological, climatic processes and modelling techniques related to these fields. Any ...
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 ...
14
votes
1answer
740 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 ...
9
votes
2answers
680 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 ...
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 ...
18
votes
1answer
363 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 ...
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 ...
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 ...
35
votes
2answers
875 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 ...
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 ...
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 ...