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Mixed Layer Depth Comparisons

The carbon model requires mixed layer depth (MLD) as an input variable. It is essential that the best estimation of MLD be used as input. These pages describe the rationale for selection of a final input set for processing.

MLD Impact on NPP

The images below show the impact of switching from using TOPS ild values to using preferred mld values [SODA through the end of 2004; NCODA/TOPS ild for the first five months of 2005; then FNMOC high res mld]. Old NPP values are shown on the left; new values are shown on the right. Significant areas to watch are: the North Pacific in the winter months, the North Atlantic in the spring, the Southern Ocean in the summer, and just south of South America and Africa in the fall. There is minimal difference in the mid latitudes, although there are some localized differences.

Using the new mld values, the carbon model now shows increased seasonal productivity in the high latitudes. Also, while it is hard to see at this scale, there are also finescale "features" arising from the ild values that are now gone.

[Note: the old npp values for 2005 (left column) were calculated using 2004 ild values (2005 values were unavailable at the time these were calculated)]