Bottom Variables in GOFS 3.1 vs ESPC-D-V02

[Sandra Slead]

Hello, 

The new ESPC-D-V02 output does not appear to contain the water_temp_bottom, salinity_bottom, water_u_bottom, and water_v_bottom variables that were included in the GOFS 3.1 dataset. The documentation for ESPC-D-V02 (https://www.hycom.org/dataserver/espc-d-v02/global-analysis), shows the 3-hourly 3z variables are output at the standard 40 layers up to 5000m and elsewhere on the page suggests the output is on the GLBy0.08 grid.  Is the ESPC-D-V02 dataset still using the GLBy0.08 41-layer archive, and if so, is it possible to also obtain the bottom variables? 

Thank you very much for the help,

Sandra

[Alan Wallcraft]

Our daily mean files, in https://data.hycom.org/datasets/ESPC-D-V02/data/daily_netcdf/2025/, include near-bottom values:

COAPS 70> ncdump -h US058GCOM-OPSnce.espc-d-031-hycom_fcst_glby008_2025053112_M0000_bot.nc | grep float
float u_barotropic_velocity(time, lat, lon) ;
float v_barotropic_velocity(time, lat, lon) ;
float height_bottom(time, lat, lon) ;
float water_u_bottom(time, lat, lon) ;
float water_v_bottom(time, lat, lon) ;
float water_temp_bottom(time, lat, lon) ;
float salinity_bottom(time, lat, lon) ;

These are calculated using hycom_bottom from HYCOM-tools, see Mixed layer, bottom and barotropic 2-D fields from ESPC-D,  which you can apply to the 3-hrly 3-D fields to get these values if you want.  These are just the deepest available values, and so  height_bottom is provided to document how far from the actual bottom this is.  This field will be the same in all _bot,nc files.

Alan.