Questions tagged [models]

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

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7 votes
2 answers
2k views

Help interpreting a wind rose diagram

Can someone comment on technical explanation of the wind rose attached? I can understand the wind is blowing between WNW & SSW with speed of 7-11 km/h. For frequency of 11-16 km/h its blowing ...
  • 417
10 votes
1 answer
13k 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?
  • 417
8 votes
3 answers
930 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 ...
  • 435
10 votes
0 answers
283 views

What is the smallest grid spacing that Eulerian air quality models should use?

The University of Washington runs the Advanced Research Weather Research & Forecasting (WRF) model in predictive mode, and then tests the skill of the model anywhere from 12 - 84 hours out from ...
  • 12.7k
6 votes
1 answer
792 views

In hydrology, what's the difference between specific and total catchment area?

I am getting stuck on the concepts of Total Catchment Area (TCA) and Specific Catchment Area (SCA) as I try to learn more about TOPMODEL and hydrology modeling. What do these metrics mean in hydrology?...
  • 1,178
4 votes
0 answers
194 views

Point source pollution model for South America

I want to model point source pollution in S. America watersheds. Specifically, given a set of pollution points and corresponding pollution output levels, I want to know the course these pollutants ...
  • 141
5 votes
1 answer
103 views

How to create a model to predict the salmon run

Are there any publicly available models that show you how to accurately predict the salmon run in both the Pacific and Atlantic oceans? This has been such a long interest of mine, I often see the ...
  • 235
8 votes
1 answer
264 views

What modelling approaches are used to predict the aurora?

Are there any resources (books/links) that discuss the mathematical tools and methods used to forecast the aurora borealis activity in a particular location? I see many websites that claim to predict ...
  • 235
8 votes
0 answers
451 views

Monitoring air pollution with Landsat satellite data

I'm trying to build an air pollution model. So far I have built one for point sources. Now I'm looking at monitoring air pollution with satellite images, based on the idea that every basic pollutant ...
  • 213
8 votes
1 answer
144 views

How to model bed load transport in channels of non-rectangular cross sections

All the formulas presented in the relevant technical literature refer to channels of rectangular cross section — the formulas assume a constant depth of flow right across the channel section. I need ...
9 votes
1 answer
205 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 ...
  • 1,811
5 votes
1 answer
6k views

Meaning of Hindcast

Let $t_0$ be the time instant of interest, $t_{-1}$ be some time before $t_0$, and $t_1$ be some instant in time after $t_0$. Now there is no confusion with forecast - if the present time is $t_0$, a ...
  • 1,811
3 votes
1 answer
180 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
3 answers
1k 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
4 answers
290 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 ...
  • 1,811
9 votes
1 answer
172 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
1 answer
772 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
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 ...
  • 1,811
2 votes
0 answers
148 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
1 answer
204 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?
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4 votes
1 answer
131 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?
  • 1,811
14 votes
2 answers
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 ...
  • 271
15 votes
1 answer
262 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 ...
  • 251
8 votes
1 answer
802 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.
  • 1,811
4 votes
1 answer
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
2 answers
795 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, ...
  • 141
14 votes
6 answers
392 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 ...
  • 243
10 votes
1 answer
261 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
1 answer
15k 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-...
11 votes
1 answer
812 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 ...
  • 219
8 votes
3 answers
481 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 ...
  • 81
14 votes
4 answers
7k 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 ...
  • 6,277
22 votes
1 answer
877 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 ...
  • 4,090
11 votes
1 answer
251 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
1 answer
162 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?...
  • 315
19 votes
2 answers
6k 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 ...
  • 1,787
13 votes
3 answers
7k 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 ...
  • 1,787
11 votes
1 answer
801 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 ...
  • 14.8k
13 votes
2 answers
156 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 ...
14 votes
2 answers
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 ...
  • 1,950
15 votes
2 answers
637 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 ...
  • 363
13 votes
2 answers
2k 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
1 answer
1k 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?
  • 7,707
8 votes
2 answers
203 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?
  • 7,707
10 votes
1 answer
254 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 ...
  • 2,622
8 votes
2 answers
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.
  • 14.8k
5 votes
3 answers
3k 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 ...
  • 4,561
9 votes
3 answers
2k 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 ...