The weather model in FS2020
Literally everyone dealing with the Microsoft Flightsimulator 2020 is blown away by the ultra-realistic weather representation within the virtual world. I remember the first computer programs trying to give an impression of virtual flight back many years. Even not so long ago the weather modeling was kind of stone-age compared to what is existing now. There are a couple of reasons for this incredible boost in realism. One is the weather modeling itself. There exists a huge weather provider named METEOBLUE. This database is used by many weather forecast apps we use in our daily life without knowing it. The same database is implemented into the FS2020.
The Method
And how does it work? Well, the secret is called “discretisation”. This means, that the entire world gets devided into so called finite volumes. In case of the FS2020, the atmosphere around the globe is represented by 250.000.000 boxes or cells in lateral direction. Each box contains all relevant weather paramters like temperature, humidity, wind speed and others important factors. In vertical direction, each box is devided into 60 layers, through which all relevant changes of the weather situation as a function of altitude can be simulated accurately.
Of course it is clear, that there is no measurement probe for each of the 250.000.000 cells around the world. But there are some, which means that most information about the weather around the earth is not known. This results in huge gaps between the cells in which the parameters are known and those in which they are not. To fill up these gaps, weather modeling algorithms are applied, so that the missing paramters can be approximated by classical numerical analysis.
Even 250.000.000 cells sounds much, compared to the size of the world and the preciseness we would expect from a forecast it’s way to coarse. In addition, weather modeling algorithms are not precise, as they are just models. The coarse resolution of the world in combination with numerical and methodological errors lead to the fact, that the virtual weather we see in the simulator does not always correspond to the weather we see when we look out of the window. This also explains the differnce between the local airport weather (METAR) and the global weather situation predicted by METEOBLUE. If the METAR data from airports would get implemented into the METEOBLUE database, we could increase the accuracy of the weather quite a lot.
But in any case it’s impressive that we have got what we got. I don’t think, that there exists a more sophisticated approach to weather modeling, which can be implemented into a large scale consumer product like the FS2020. I’m very happy with the weather representation and I’m sure it will need quite a while until the current system gets replaced by a better and more accurate approach.
Case study Hurricane Grace
We all heard about the hurricane “Grace”, which hit Haiti very hard a few days ago. To test the weather model, I jumped into the Flightsimulator and checked out the weather over Haiti. And of course, the modeling of the weather is not precise due to the facts described above, but the large scale representation of the weather was incredibly correct. Literally all of Haiti was covered in clouds and severe thunderstorms. Flying through them would not have been a good idea.
So, I decided to do a few timelapses of the weather situation of the thunderstorms, which were currently crossing Haitit. Very nice are the cloud formation and atmospheric mechanics. No matter if it is highly accurate or not, for sure it is the best atmospheric model I have ever seen!
