What is the minimum percentile IIM Jammu

Bumai

Nowadays, predictions are based not only on a calculated solution, but on a whole "ensemble" of predictions. In addition to the main run of the model, we offer different variants for the most important forecast parameters in these diagrams, the so-called ensemble members. On the one hand, these are generated by changing the input drive data at the model edges. On the other hand, each variant is modified with regard to individual settings of the model physics and / or initial conditions, so that differences arise between the runs. In this way, a range of possible solutions is obtained which, especially in active weather (e.g. storms, thunderstorms) allow a statement to be made about the probability of certain events occurring.

When you point the mouse over a time series, you can see the calculated maximum, minimum and mean of all solutions for the respective date in the Global US model. Percentiles are also given for the ensemble of the ECMWF. The 90% percentile is the value that only 10% of all ensemble members (solutions) exceed, or in other words: 90% of all solutions remain below this value. The 10% percentile is exactly the opposite: 90% of all solutions remain above this value.

The percentiles highlight something like "outliers". This means that ensemble members who are outside the band spanned by the percentiles can be seen as an unlikely outsider solution. Sometimes it happens that you have two main solutions, for example 20 out of 50 solutions very high, 20 out of 50 solutions very low and only a few in the middle. Then the percentiles are very far apart. Conversely, if most of the members are around the mean, then the percentiles are close together.

Note snow depth

With the ensemble of the ECMWF you can choose the snow depth under Precipitation. Please note here that the resolution of the ECMWF model for the main run is 9x9km, for the ensemble members it is only 18x18 km and therefore mountains and valleys are insufficiently resolved. Particularly in the Alps, narrow valleys are not resolved, so that snow is often calculated for places in the valley in winter, but it can only be found in the mountains. Therefore, use our snow depth of the Super HD model with 1x1 km resolution for a period of up to 3 days, where mountains and valleys are perfectly mapped.