Gradient measure and Jacobi sets for estimation of interrelationship between geophysical multifields

We consider a problem of estimation of relationship between scalar 2D fields using gradient measure and Jacobi sets. The gradient measure method is based on estimation of alignment of gradients in every point of fields. The Jacobi set is the set of critical points of the restrictions of one function to the intersection of level sets of the other functions. We present the results of a numerical experiment for the case of multifield containing two fields: geopotential height on isobaric level 300 hPa and total ozone column, under influence of disturbing factor — intensive solar proton events in January 2005. Estimation of interrelationship by gradient measure indicates strengthening of interaction between fields for period 16^th – 22^th January 2005. The estimation made by Jacobi sets computation also shown strengthening of relation between analysed fields during solar proton events.