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18 votes
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Great Pacific Garbage Patch Equilibrium Points

Yes, you're right, there should be (at least one) saddle point in the middle of the loop. And indeed, if you search for illustrations of Pacific ocean circulation, you can see the saddle point in ...
Ilmari Karonen's user avatar
18 votes

Great Pacific Garbage Patch Equilibrium Points

Theoretically, I agree that there should be one instable equilibrium point between the two stable equilibrium points when we have a 2D current field. However, there are some additional components of ...
daniel.heydebreck's user avatar
17 votes
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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 ...
milancurcic's user avatar
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12 votes
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Predicting rainfall with governing equations

The Barotropic vorticity equation is insufficient to model rain. Part of this is due to the word 'Barotropic,' which indicates a lack of thermal gradient. The other reason is that while vorticity is a ...
BarocliniCplusplus's user avatar
10 votes
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How to calculate w-wind?

Omega, ω is closely related to w in meteorology. It can be moved towards w using the chain (this reminder from Watkins at SJSU helped)... ...
JeopardyTempest's user avatar
10 votes

What is the difference between GFS analysis and GFS forecast data?

I'm no expert at this, I've just been working with a variety of gfs gribs for a while now. The only thing I know about them is what I've read and I'll cite them here. I don't know where you got ...
user6972's user avatar
  • 301
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, ...
jgadoury's user avatar
  • 315
9 votes
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Long-term Wind Speed Forecasting: reality or wishful thinking?

Warning: "long-term wind-speed forecasting for generation" has (at least) two very different meanings. One refers to forecasting a distribution of wind speeds; the other refers to hour-by-hour (or ...
410 gone's user avatar
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9 votes
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How to run earth system, land surface and climate models?

As alluded to in some of the comments, all of the CMIP5 models will have been run on supercomputers, and it takes a lot of effort to get one of them running on a new platform, even for a team who know ...
Deditos's user avatar
  • 3,950
8 votes
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Kalman - Data assimilation with external model

$M$ is the forward model you are using. It is the dynamical model used to solve whatever discrete equation evolves the field ($d?/dt=$). The best way to start with data assimilation and understand ...
arkaia's user avatar
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8 votes

Predicting rainfall with governing equations

TL;DR: Global NWP models such as NCEP's GFS (free access) and ECMWF's IFS (restricted access) provide forecasts at a horizontal scale of a few tens of kilometers every few hours. Starting from global ...
Nerevar's user avatar
  • 81
8 votes
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Why doesn't Wolfram Alpha show low gravitational acceleration for the Hudson Bay?

Wolfram Alpha reports values between 9.78 and 9.88 m/s2 depending on the location, which is odd because it should stay within the range 9.76 - 9.83 all over the world. It also seems to be using the ...
FSimardGIS's user avatar
8 votes
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Do tectonic plates "float" over the mantle and "collide" like icebergs?

you are missing a big factor, the plates are not moving due to the momentum of an initial impulse. They are being actively moved by the push and pull of mantle convection. Much like how icebergs are ...
John's user avatar
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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 ...
Gordon Stanger's user avatar
7 votes

Correct phrase for a 'forgetful' natural system?

How would you call a system that displays such 'forgetfulness'? In one word, dissipative. In multiple words, a system whose autocorrelation function tends to zero as time tends to infinity. Note ...
David Hammen's user avatar
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7 votes

Are we now and/or have we been in the RCP8.5 scenario?

In short, I would say that it is too soon to say. But, if I were forced to guess: I would indeed incline to say that we live in a RCP 8.5-ish scenario. I'm not an expert at all on climate models or ...
Camilo Rada's user avatar
  • 17.7k
7 votes

How to run earth system, land surface and climate models?

We are moving all of CESM to open source - in particular here is the latest version of the Community Terrestrial Systems Model (CTSM) https://github.com/ESCOMP/ctsm Formerly known as CLM, CTSM ...
Jim Edwards's user avatar
7 votes
Accepted

How/where is randomness/stochasticity used in weather prediction

Probability is used in weather forecasting. I will only highlight some examples due to my lack of knowledge in some areas. Before initializing a forecast model the data needs to be assimilated. That ...
Joscha Fregin's user avatar
7 votes
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Why is it that "With higher CO2, the dry gets drier and the wet gets wetter"?

To my best knowledge, the paper by Held & Soden (2006) is the first paper that discussed the concept of the rich get richer. They used the climate change experiments generated for the Fourth ...
ahmathelte's user avatar
6 votes

Climate change review for a scientist

EnergyNumbers suggestion is good, but you can only go so far in reading about it second hand. I suggest that you pick a grid cell of interest, then go to the World Bank's climate change knowledge ...
Gordon Stanger's user avatar
6 votes

Correct phrase for a 'forgetful' natural system?

From physics standpoint I would say that such system is stable. For example think of a ball on a surface. If the ball is initially on the top of a hill a push would move the ball into the slope that ...
Communisty's user avatar
  • 1,064
6 votes

Waves in very thin layer

The problem with the cancelling you suggested is that it is imposed globally for the PDE and not locally (just on the thin layer). Usually when we talk about vertically layered media we use a plane ...
dvoytan's user avatar
  • 121
6 votes
Accepted

Milancovich analysis

The most common period to use is 30-years, which comes from the idea of climate normals used in NWP. Using only 10 years even global mean temperature will see the influence of a single large El Nino ...
Deditos's user avatar
  • 3,950
5 votes
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Is there a simple temperature prediction model?

Simple? Depends upon the level of accuracy you are looking for. Insolation alone is a rough indicator of sea surface temperatures. image from http://www.ospo.noaa.gov/Products/ocean/sst/contour/ In ...
Gordon Stanger's user avatar
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' ...
Peter9192's user avatar
  • 201
5 votes
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Units of wave spectrum

I understand that the integral of the spectrum over all frequencies is the variance which means that the integral should have $m^2$ units? Please correct me if I am wrong. You are correct. If ...
milancurcic's user avatar
  • 4,993
5 votes
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What does the degree and order of Spherical Harmonics mean?

Citing from Wikipedia: $Y_l^m$ is called a spherical harmonic function of degree $l$ and order $m$. If we take the real part of the spherical harmonics only, there is a nice visual explanation for ...
Joscha Fregin's user avatar
5 votes

Predicting rainfall with governing equations

You could look further into how currently used weather models actually work. If you want to do a prediction you will have to run a model which is not just as simple as your question would imply. There ...
Communisty's user avatar
  • 1,064
5 votes

Debunking weather conspiracy with statistics - why does temperature rise then fall for last weekend in June in recent years

You are asking the wrong question. The real question is why some podunk single city festival and not other larger more costly events, like space launches, national holidays, military campaigns, ...
John's user avatar
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