I immediately shouted "but how many flood regions are there" when I saw the headline! I definitely did not immediately think about the assumption of independence and importance of the geographical boundaries so thoughtfully though. I'm glad to see yet another demonstration of both the power and limitations of modeling using a poisson process.
Hi.... Do this argumentation also works in the case of the European drought? I've been reading that 2022 drought is the worst drought in 500 years. I guess not, because the drought is widespread event while the floods are more "localized" events. Thank you.
Hi! The two situations are a little bit different, I think. In the case of the flooding, we could have two floods separated by vast distances that occur in very different terrain with different climates. In this case, I would say it is not necessarily clear how to define which is the bigger flood. We could ask which flood contained more water, which had a larger increase in depth of affected rivers, which cost more to clean up, etc. So, I would say that we don't typically compare floods in different locations. For this reason, I don't think we normally talk about "the worst flood in America", say, in a given year; instead we look at flooding as a local phenomenon and compare a current flood to others in the same location in history. Then, because we are making local comparisons, we need to think about how many different "local" regions we are talking about over the US. As you pointed out, the European drought is widespread--it is over a substantial portion of the continent. Here, unlike the flooding case, it makes more sense to talk about something like "the worst drought in Europe". If we were talking about more localized events, then the two cases would be more similar. (Perhaps if we were talking about smaller droughts, one could look at, say, a drought in Italy and a drought in Spain as separate events. Then the cases would be more analogous.) Thanks for the question!
My first thought on this was that the distribution is not a Poisson disrribution, but more of a fat tail distribution, power law or Levy. The main assumption that the events happen at a constant rate is that they are independent in time is probably not true. So it is possible for instance that while there were 1000 foods in the last million years, so 1 flood per 1000 years, most floods cluster in groups of 10 a year every 10000 years.
Hi! Questions?
I immediately shouted "but how many flood regions are there" when I saw the headline! I definitely did not immediately think about the assumption of independence and importance of the geographical boundaries so thoughtfully though. I'm glad to see yet another demonstration of both the power and limitations of modeling using a poisson process.
I'm very glad it was useful. Much appreciated!
You guys make some great videos! It’s a shame more they aren’t getting to more people
Thanks! Much appreciated.
Thanks!
Hi.... Do this argumentation also works in the case of the European drought? I've been reading that 2022 drought is the worst drought in 500 years. I guess not, because the drought is widespread event while the floods are more "localized" events. Thank you.
Hi!
The two situations are a little bit different, I think. In the case of the flooding, we could have two floods separated by vast distances that occur in very different terrain with different climates. In this case, I would say it is not necessarily clear how to define which is the bigger flood. We could ask which flood contained more water, which had a larger increase in depth of affected rivers, which cost more to clean up, etc. So, I would say that we don't typically compare floods in different locations. For this reason, I don't think we normally talk about "the worst flood in America", say, in a given year; instead we look at flooding as a local phenomenon and compare a current flood to others in the same location in history. Then, because we are making local comparisons, we need to think about how many different "local" regions we are talking about over the US.
As you pointed out, the European drought is widespread--it is over a substantial portion of the continent. Here, unlike the flooding case, it makes more sense to talk about something like "the worst drought in Europe". If we were talking about more localized events, then the two cases would be more similar. (Perhaps if we were talking about smaller droughts, one could look at, say, a drought in Italy and a drought in Spain as separate events. Then the cases would be more analogous.)
Thanks for the question!
My first thought on this was that the distribution is not a Poisson disrribution, but more of a fat tail distribution, power law or Levy. The main assumption that the events happen at a constant rate is that they are independent in time is probably not true. So it is possible for instance that while there were 1000 foods in the last million years, so 1 flood per 1000 years, most floods cluster in groups of 10 a year every 10000 years.
Yup, and if floods have a tendency to cluster, the headline is even less meaningful!
Good observation, and thanks for the donations! Much appreciated!