Hello everyone,
I have a question if there is someone has the answer.
I tried to program a code to cluster air masses for a period of 2 months, following the method used by hysplit but I can't find the same results. after, I tried to make an approximation to minimize the computation time, when I calculated the Euclidean distance between the trajectories, I tried not to go through all the endpoints of the trajectories, but I took a step of 6 endpoints and by chance I find the desired results.
The problem now is when I test this code over a period of 2 years with trajectories of different length, I discover that this "step" is no longer valid. I want to know is what I have to do to get the same results.
Thank you.
Program code to cluster air masses
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Re: Program code to cluster air masses
Hi,
I have this problem too. I'm trying to code a program that can statistically analyze the air masses generated by Hysplit. And among the techniques I work on, it's clustering. I specifically chose the clustering based on TSV (total spatial variance) as Hysplit does.
But when I compare the clustering results obtained by using my code with the Hysplit results. I found that they are similar if I use a small number of trajectories and become different if I use a large number of trajectories.And when I found this difference . I compared the TSV values calculated by my code and by Hysplit for the same number of clusters. I noticed that my code produces the minimum (better) value. This means that Hysplit does some approximation that I don't. I want to know if that is true with some explanation please.
Thank you in advance.
I have this problem too. I'm trying to code a program that can statistically analyze the air masses generated by Hysplit. And among the techniques I work on, it's clustering. I specifically chose the clustering based on TSV (total spatial variance) as Hysplit does.
But when I compare the clustering results obtained by using my code with the Hysplit results. I found that they are similar if I use a small number of trajectories and become different if I use a large number of trajectories.And when I found this difference . I compared the TSV values calculated by my code and by Hysplit for the same number of clusters. I noticed that my code produces the minimum (better) value. This means that Hysplit does some approximation that I don't. I want to know if that is true with some explanation please.
Thank you in advance.
Re: Program code to cluster air masses
Can you give some more specific information.
What are you using for the inputs to the clustering utility?
hours to cluster, time interval, trajectory skip
https://www.ready.noaa.gov/documents/Tu ... _clus.html
What are you using for the inputs to the clustering utility?
hours to cluster, time interval, trajectory skip
https://www.ready.noaa.gov/documents/Tu ... _clus.html