FAQ

Here is a list of frequently asked questions (FAQ):

Can I use Verif to verify gridded forecasts against gridded analyses?

Yes, this is technically possible. Since Verif only supports 1D locations, you need to convert the 2D grid into a 1D vector of positions. Note that for large grids, the verification files will likely be large, which might lead to long processing times.

Does Verif support interpolation from grid to points?

No, Verif requires the user to interpolate gridded forecasts to the observation points. There are many packages that does this (checkout https://github.com/metno/gridpp).

Can I do spatial verification with Verif?

Not really. Verif was designed for verification at point locations and many spatial scores require gridded fields. Verif does have the ability to compute the fractions skill score (-m fss) but note that this only computes the score based on the irregularily spaced observations available within each spatial scale.

How can I avoid the "double-penalty" problem with precipitation verification?

Verif does not support spatial scores like fractions skill score, which can be used to alleviate the problem. The other option is to aggregate observations and forecasts in time. This will partially solve this issue. In version 1.3 this is supported.

If I have multiple verif files, do all files need to contain observations?

No, as long as one of the files contains observations, Verif will be able to use them when verifying the other files.