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 ...
- 8,837
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
...
- 454
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 =...
- 450
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 ...
- 5,810
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 ...
- 14k
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 ...
- 8,826
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 ...
- 3,980
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 ...
- 8,837
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.
...
- 315
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 ...
- 31
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, ...
- 17.7k
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, ...
- 391
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 ...
- 188
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....
- 15.5k
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 ...
- 2,813
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 ...
- 8,837
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 ...
- 5,165
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 ...
- 325
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 ...
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/...
- 454
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, ...
- 8,345
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 ...
1
vote
divergence of static stability identical parameters
From the code you provided, you used finite difference approximation to the differential expressions. That is the root of the difference. When you use finite difference schemes (here centered ...
- 191
1
vote
Can we know if a numerical model will converge or not according to the boundary conditions?
The proposition of this question says nothing about the size of the domain, or how the domain has been discretized. And yes, the numerical model will converge if the necessary boundary conditions ...
- 11
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 ...
- 8,837
1
vote
How to de-stagger (or unstagger) WRF wind fields?
The simplest way I've found in Python is to use the getvar function with the 'ua,' 'va,' or 'wa' variables from the WRF-Python module. Alternatively, you can take the midpoint between the staggers.
...
- 8,837
1
vote
Temperature Advection using finite differences with gridded data
I've come to a solution. I have followed @gansub's suggestion to check what there is already there, before reinventing the wheel. I found MetPy's code very (too) well structured, so the code for ...
- 652
1
vote
Temperature Advection using finite differences with gridded data
So i don't know for how many timesteps you've integrated. And I don't really understand what you have done to obtain the temperature $\rm T[t,s,y,x]$ in your second box, but this seems a bit like a ...
- 3,271
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