Ø In both add-on (add winds in the ctrlA observation network)
and delete-out (delete
winds in the ctrlB observation network) experiments, the winds show the significant
impact over Tropics
Ø Winds have large impact over mid-latitude in SH in add-on
experiment, but does not
shown this impact in the delete-out experiment, which is due to the significant
covariance between winds and mass field in this area