| 3 | | |
| 4 | | == Version 3.1.2 - June 5, 2026 == |
| | 3 | == Version 3.1.3 - October 11, 2026 == |
| | 4 | |
| | 5 | This is a bug-fix release in the search operations for local observations in localized ensemble filters, e.g. LESTKF, LETKF. Only affected are applications using geographic coordinates with great-circle distance (haversine function, i.e. `thisobs%disttype=3` or `=13`). Most corrections concern only the non-isotropic localization (`disttype==13`). The correction for isotropic localization should not have an effect on the results, but it might have on the counted observations. Below a some more details about the errors that are corrected. |
| | 6 | |
| | 7 | For non-isotropic localization: |
| | 8 | * There were some inaccuracies which lead to a miscalculation in the distance between the local analysis domain and an observation or in the computation of the directional localization cut-off radius. Mainly, this could exclude observations within the specific cut-off distances. It some case it could include some observations which are slightly more distance than the radii specified. The effects should be small. |
| | 9 | * Under the special conditions of using localization in 3 dimensions, but then setting either the both horizontal radii or vertical radius to zero, a division by zero could happen. |
| | 10 | |
| | 11 | For isotropic localization: |
| | 12 | * For the optimized search methods (`search_type>=11`) for local observations some distances checks used `<`, while most others used `<=`. Now all checks use `<=`. This should not have an effect if one uses the smooth observation weighting, e.g. `locweight=2` or `locweight=4` because in this case the weight of observations at the maximum distance is zero. |
| | 13 | |
| | 14 | |
| | 15 | ---- |
| | 16 | |
| | 17 | == Previous releases == |
| | 18 | |
| | 19 | |
| | 20 | === Version 3.1.2 - June 5, 2026 === |
