11 votes

What exactly is a model grid?

A model is a simplified representation of a system. Rather than try to model everything down to the microscopic level, or as vectors, we often aggregate phenomena across geographic areas, to simplify ...
410 gone's user avatar
  • 4,090
8 votes

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

Presume that the atmosphere can be modeled with waves of different frequencies. Therefore, the atmosphere can be written as a series of sine and cosine functions with different frequencies and ...
BarocliniCplusplus's user avatar
7 votes
Accepted

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

First download the esmf tar file from http://www.earthsystemmodeling.org/esmf_releases/public/ESMF_7_1_0r/reg/ESMF_Framework_Down.html Then install netcdf library and gfortran compiler using ...
Manmeet Singh's user avatar
6 votes
Accepted

How are boundary conditions considered in PDEs?

In any solution to a PDE, whether analytical or numerical, you will always need as many BCs as the number of derivative steps. For examples: $$dY/dt = k Y$$ needs one BC while $$\partial Y/\partial t =...
Jeffrey J Weimer's user avatar
5 votes
Accepted

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

This question is a little vague, with multiple aspects, but I shall do my best. Computing resources Some universities have their own clusters or supercomputers. But many countries also have regional ...
Semidiurnal Simon's user avatar
5 votes

What exactly is a model grid?

To add a bit more mathematical conception to the idea of a grid: think about a 2-D grid(X,Y) as a matrix: this matrix represents a solution to the system of equations you are trying to solve at grid ...
Neo's user avatar
  • 6,456
5 votes

What exactly is a model grid?

Specifically the term the values are archived on 2.5° grid means that the values that are being reported are being saved and are available at that resolution for historical values. The higher ...
Ben MS's user avatar
  • 568
4 votes
Accepted

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

The hydroxyl radical chemistry is not modeled explicitly in air quality models, so numerical stability is not an issue. Instead, OH is held in pseudo-steady-state. For instance, see CMAQ's ...
f.thorpe's user avatar
  • 13.5k
4 votes

Effect of urbanization on weather events

I did my undergraduate capstone on observational moisture changes around cities. It's an interesting field, though it certainly seems fairly challenging to draw out and explain changes given the ...
JeopardyTempest's user avatar
3 votes

How to determine the orientation of coastline from NetCDF file

It should be noted that NetCDF data just describes the format that the data is in. One dataset that I know of (IBTrACS) contains data that is not gridded data, and also contains a landmask. But this ...
BarocliniCplusplus's user avatar
3 votes

Why RBF is gridless and kriging is not?

Kriging IS gridless. In fact Kriging and RBF are formally equivalent. The reason kriging tends to used on grids is more historical in the oil industry than anything else. The original papers in ...
Colin Daly's user avatar
3 votes
Accepted

Simple and realistic data for glacier modeling

Testing and model inter-comparison have been an important part of glacier models developments. One of the main numerical modelling suites used by the glaciology community is Elmer Ice, a full-Stokes, ...
Camilo Rada's user avatar
  • 17.6k
3 votes

Effect of urbanization on weather events

This is a very interesting topic, since climate and land surface model is becoming more powerful and with higher resolution data available, it is possible to include urban land tiles in the model. ...
Felix Leung's user avatar
3 votes

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

In fact, there are many chemical transport models which solve the radical chemistry without steady-state approximations. The equations are very stiff but can be integrated with suitable methods, ...
jvir's user avatar
  • 391
3 votes

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

Another UK perspective here to supplement Semidiurnal Simon’s answer (which reflects my experience too). The UK research community is dominated by a single family of models known collectively as the ...
Deditos's user avatar
  • 3,960
3 votes

Bias correction of CMIP6 projections

It depends on your goal. So, you should ask yourself first which variables you're studying, what you're doing with them, and which kind of questions you want to ask afterwards. In general, CMIP6 data ...
Jorn's user avatar
  • 163
2 votes

Why should dynamical downscaling of meteorological data be made incrementally?

The basic answer to your question is that there needs to be an overlap between the spectra of the two domains. One way to think about it is that there needs to be a connection between the Kolmogorov ...
arkaia's user avatar
  • 15.4k
2 votes

How to set up a domain from namelist in WRF?

There is a WRF domain Wizard offered by ESRL. You can download it here. Also, don't make the same mistake I made using Lambert Conformal- keep stand_lon the same as your ref_lon.
BarocliniCplusplus's user avatar
2 votes

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

I have been using the routines in nctoolbox (also check here) that do all the slicing (vertical, horizontal, following a track). The repository is in GitHub. The one you should looking at is vsliceg....
arkaia's user avatar
  • 15.4k
2 votes

Effect of urbanization on weather events

Now, What challenges and possibilities are there in this particular research field? Now that urban effects on regional weather can be observed, modeled, and to a large degree verified, all that ...
Knob Scratcher's user avatar
2 votes

Calculate the number of model grid cells covering a specific country

Here is a simple 'back of the napkin' idea for Python: Get a shapefile of the borders and use Python to create a polygon of the borders. Use mpl_toolkits to convert the climate model to X and Y ...
BarocliniCplusplus's user avatar
2 votes

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

I got the solution https://www.researchgate.net/post/How_to_convert_the_units_of_specific_cloud_liquid_water_from_ERA5_kg_kg_to_kg_m2 and https://www.nwpsaf.eu/site/download/documentation/rtm/...
Manmeet Singh's user avatar
2 votes

Difference between model parameter and observable parameter

Inverse problems deal with creating theories based on observed data, as opposed to making predictions about the real world based on existing theoretical models, so the "results of the measurement of ...
Ash's user avatar
  • 4,260
2 votes

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

I actually just found an article that explains such a calculation in detail, using a matrix propagator method: Padovan et al. 2018 This is a calculation for gas giants or bodies in hydrostatic ...
theWrongAlice's user avatar
2 votes

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

Actually, you probably shouldn't install it. If you're comfortable using Linux, then you would be better advised to use the docker container instead, with it already installed. That way your system ...
Software Engineer's user avatar
2 votes
Accepted

Understanding Graphs for Velocity and Temperature Solutions for Parallel Sided Slab on Slope Problem

In Matlab, trigonometry functions work with angles in radians, see for example the description of the sin function: Input angle in radians, specified as a scalar, ...
Jean-Marie Prival's user avatar
2 votes
Accepted

Estimating atmospheric vertical motion from 3D fields in WRF output

After a bit of digging, it seems that vertically integrating the continuity equation in pressure coordinates (shown above) is a sound approach for estimating vertical motion in numerical model output ...
Brendan Wallace's user avatar
1 vote

Why are all the variables ( DRY_DEP_FLUX and WET_DEP_FLUX) zero in a wrf model output in all the time steps

Well I can see one major reason the dry deposition is not working- the namelist variable for gas deposition (gas_drydep_opt) is turned off. I am not entirely sure how the wet deposition works, though ...
BarocliniCplusplus's user avatar

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