Questions tagged [models]

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

Filter by
Sorted by
Tagged with
2
votes
2answers
124 views

Modelling sea levels with gravitational parameters

Are there any publicly available programs or source code for modelling global (or local) changes in sea level which include parameters for gravitational tidal effects? I have a physics background, ...
2
votes
0answers
71 views

Inverse model problem

I have a dataset for river water, rain water and geology (main elements and trace elements). I want to apportion the contribution of geology to water chemistry using for that purpose a model. I was ...
5
votes
1answer
267 views

What is the difference between the freezing level and 0C isotherm in NOAA's GFS?

I'm playing around with NOAA's GFS forecast data and I see that it contains both a "0C isotherm level" and a "Highest tropospheric freezing level". Could someone tell me the difference between these ...
16
votes
2answers
2k 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 ...
7
votes
2answers
834 views

Long-term Wind Speed Forecasting: reality or wishful thinking?

I have been studying/working with Wind Energy for a while and, one of my main responsabilities right now is to search for adequate long-term wind speed forecasting models. However, 2 things strike me ...
5
votes
1answer
222 views

Timeline of atmospheric model resolution

I'm looking for a graph of improvements in spatial resolution for any atmospheric model (such as the UK Met Office Unified Model or ECMWF IFS). Ideally it would include a range of historical model ...
10
votes
2answers
764 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 ...
6
votes
1answer
2k views

Compute direction of gravity vector

As I understand to compute vector of gravity not saficient to compute normal to elipsoid, but we need to computer normal to geoid (by definition geoid is a surface to which the force of gravity is ...
7
votes
2answers
1k 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 ...
10
votes
1answer
9k 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
3answers
661 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 ...
5
votes
1answer
376 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?...
3
votes
0answers
192 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 ...
5
votes
1answer
82 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 ...
8
votes
1answer
186 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 ...
7
votes
0answers
432 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 ...
8
votes
1answer
139 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
1answer
202 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 ...
5
votes
1answer
4k 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 ...
3
votes
1answer
160 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
948 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
234 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
156 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
696 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
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 ...
2
votes
0answers
140 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
156 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
125 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
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 ...
15
votes
0answers
223 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
590 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
717 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
366 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
237 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
12k 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
735 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
395 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
6k 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
693 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
238 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
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?...
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 ...
13
votes
3answers
6k 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
752 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
147 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
609 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 ...