19
votes
Accepted
How bad is geo-engineering?
The bad part about geo-engineering are the unknown unknowns.
Our climate models are wrong. All models are wrong, but some are useful.. Our models are useful, but not quite useful enough to trust ...
- 11.6k
17
votes
Accepted
Why is WRF most often configured at 3:1 nesting ratio?
To understand why the nesting ratio of 3 is preferred to the nesting ratio of 2, it is important to understand the following two features of WRF:
1) Grids are Arakawa C-staggered: mass points are at ...
- 4,983
13
votes
Accepted
What is the formula used for atmospheric visibility?
I calculate surface visibility from WRF output using a calculation that I adapted from DTC's Unified Post Processor, specifically from their Fortran routine found in ...
- 4,983
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 ...
- 4,090
11
votes
Accepted
Temperature change in Earth atmosphere models?
There's some kind of explanation about the units under the picture. The formula is based off the average temperature in degrees Celsius (measured over the entire year, and the entire Earth), which is ...
- 748
10
votes
On the light difference between morning and afternoon
I am asking why the light of a clear day is not symmetrically changing centered at noon.
Trying to attribute this to a single cause misses the point. There are multiple causes. Other than lighting ...
- 23.1k
9
votes
Accepted
Interpolate Gaussian grids to regular fixed grids using bilinear interpolation?
climate data operators (CDO)
define grid
We define a lat-lon target grid with 1°x1° grid cell size 30x30 grid cells starting at 40°N and -10°E (=10°W):
...
- 2,661
9
votes
Does finer input data lead to a better model accuracy?
My experience with the WRF is in tropical cyclone simulation, but here are some things to consider:
Smaller scale information might already be resolved in your higher resolution initial conditions, ...
- 315
8
votes
Accepted
Why does computation cost increase 24 times when the spatial resolution doubles?
I can't answer why there's a 24x increase, according to the textbook - but it may well be the case for a specific model. In general,
If you double the resolution of a 3D model in each dimension, you ...
- 5,800
8
votes
How bad is geo-engineering?
Seconding eveything that @gerrit mentioned.
Additionally, another major problem with geo-engineering is that once we've started these processes and essentially borrowed time to offset mitigation ...
- 572
8
votes
On the light difference between morning and afternoon
I believe the effects you are talking about are due to scattering by dust and water vapor in the atmosphere. During the night winds are lower and wet areas don't dry out as fast as during the day. ...
- 822
7
votes
Accepted
Calculate precipitation from WRF model output
Use (1) Precipitation, as it is the sum of convective and non-convective precipitation, integrate it over one day, voilà.
converting [$kg/(m^2 s)$] (precip):
$$ precip [kg/(m^2 s)] \cdot dt [s] \cdot ...
- 438
7
votes
How does the tornado chaser locate the spot?
It starts by identifying days with good overlay of shear and surface-based instability. In the US we have the Storm Prediction Center that helps indicate such days looking at models. Generally the ...
- 8,713
7
votes
Does finer input data lead to a better model accuracy?
Yes, of course finer input data can lead to better model accuracy, but only if the model's conceptualization is close to the mark. Of the many problems of climatic model misinterpretation, I would ...
- 14.2k
7
votes
Accepted
How to calculate the solar radiation at any place, any time
Look at the pysolar docs (http://pysolar.readthedocs.io/en/latest/) under "Estimate of clear sky radiation". The algorithm does not return zeros at night, but instead just plugs those ...
- 1,381
7
votes
How thin is our atmosphere relative to the size of Earth?
The answer to your question depends on where one defines the edge of the atmosphere.
The Earth's atmosphere is layered. The thickness, density of composition of each layer varies. The five layers are:
...
- 24.6k
6
votes
Take all the CO2 in the atmosphere and put it into a layer on the surface of earth, how thick would the layer be?
Ok, based on the comments above, this is where I am at...
earth's radius is $6371 \text{ km}$
earth is a sphere
There is approximately $3 \cdot 10^{15}$ kg of CO2 in earth's atmosphere
The density ...
- 221
6
votes
Accepted
What is the meaning of step in ERA reanalysis data?
The "step" is the number of hours the ERA re-forecast has been run into the future from the "time" of the re-analysis.
For example, asking for ERA data with time = 12:00 and step = 0 means asking for ...
- 1,681
6
votes
Why are inversion layers so important in meteorology?
Farrenthope is correct, but I would like to add some detail.
An inversion occurs when the air is warmer than the ground. It is called an inversion because it is the opposite of what occurs during the ...
- 8,684
6
votes
Accepted
Python, R or etc.?
In my opinion, python is a more established global language that is used by many more disciplines/users, compared to R. This can be advantageous because examples/tutorials are everywhere and you can ...
- 13.5k
6
votes
Accepted
What is the atmospheric pressure at the deepest point of the Kidd mine?
From the book Environmental Engineering in South African Mines, The Mine Ventilation Society of South Africa, 1989, pp 451-455.
The equation required is:
$P \ = \ P_{atm}\cdot e^{\frac{-gMh}{1000R\...
- 24.6k
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 ...
- 518
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 ...
- 6,456
5
votes
Why is radiation and total precipitation not available in ERA Interim Reanalysis at step 0?
The ERA archive description document, Berrisford et al (2011) "The ERA-Interim archive Version 2.0", provides additional information about what is available. It's less explicit on the why, but we can ...
- 3,940
5
votes
Why are inversion layers so important in meteorology?
Temperature inversions are important to meteorology and pollution because they are the boundary for atmospheric mixing. If there is a strong inversion, the air above and below an inversion do not ...
- 13.5k
5
votes
Accepted
Running WRF with ECMWF GRIB2 model levels
I finally solved this problem with the following steps:
Download the ECMWF data separately for model level variables (Q,T,U,V and geopotential) and surface variables. In this way, you will get 'pure' ...
- 201
5
votes
How to compute du/dx and dv/dy in moisture flux convergence?
I imagine you have a horizontal grid (x,y) and wind components u(x,y) and v(x,y).
Normally we do 1-degree of latitude constant (y-dimension) and equal to 110000 m. So your ...
- 607
5
votes
Accepted
Correlation and causation
Convergent cross mapping (CCM) is a recently developed tool to answer the question you've asked. It's based on tools developed in nonlinear time series analysis and dynamical systems theory. It allows ...
- 432
5
votes
How does temperature impact the elevation distribution of orographic precipitation?
Examining two extreme cases, one very cold and the other very warm, the amount of precipitable water in the very cold one will be far less than that in the very warm one. Even fully saturated, the ...
- 348
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