The land sea mask used in the ECMWF IFS changed with the introduction of 41R1. Figures in the table below illustrate where there have been changes (please refer to the title on each image). Mostly the changes were for the better, with some notable improvements over Europe (mostly the land area is now bigger - row 9 below shows an example). However there were also some areas of degradation, specifically in the Pacific, where some islands have unfortunately 'disappeared' due to errors in the new reference geographical dataset - all known instances of disappearing islands are shown on the following table, in rows 2-7. Locations of these are also marked on the global map on row 1. Following consultation it was decided to wait until the next cycle (41R2) before these errors are rectified. Row 8 illustrates that there have also been some significant changes in the land and sea points around Antarctica.
| Row Label | Area | Map Link | Comments |
|---|---|---|---|
| 1 | Globe |  | Shows locations of all subsequent plots |
| 2 | Samoa and Niue |  | Samoa reduced from 12 land gridpoints to 1. Niue is now sea point. |
| 3 | Tahiti and the Marquesas |  | Main Tahiti and Marquesas islands are now just sea points. |
| 4 | Chatham |  | Chatham island is now just sea points. |
| 5 | Micronesia |  | Micronesia island is now just a sea point. |
| 6 | Marion |  | Marion island is now just a sea point. |
| 7 | Noname |  | Nameless island near Antarctica is now just a sea point (lower left of plot) |
| 8 | Antarctic Peninsular |  | The distinction between permanent sea ice and land around Antarctica is blurred. Locally around Antarctica there are some large changes in 41R1 compared to 40R1 (not just in the area shown). |
| 9 | Baltic |  | This illustrates the fact that over Europe there are more land points in 41R1 than there in 40R1 (more green dots); this is generally around Europe, not just around Baltic. Land and sea depiction in 41R1 is believed to be much more accurate in the European region. |