NOAA NWLON observations broken after NAVD88 ERDDAP update

[youngmorse]

After the update to get NWLON data in NAVD88 instead of MLLW, the NOAA stations on MD WL dashboard were throwing errors. I updated the stations in Buoy Barn to the new variable (NAVD_meters) and standard name (sea_surface_height_above_geospatial_datum).

The obs data were plotting the new data but there was definitely a mismatch between datums for the predicted and observation. I thought it was the datum offsets so I updated the sea_surface_height_above_geopotential_datum datasets relative to NAVD88 from the Tides & Currents website (they were relative to MLLW before).

I think the MD Water Level app needs an update to know NAVD88 is available for these stations (disabled in the datum toggle) to do the datum conversions.

I disabled the NAVD88 observation datasets for now in Buoy Barn.

There are 5 that don't have a NAVD88 offset on the Tides & Currents website so I removed the MLLW offsets that were in Buoy Barn before the update.

• ERDDAP link / Tides & Currents Datum link
• NLHC3 (New Haven)
• NTKM3 (Nantucket)
• CPTR1 (Conimicut Light RI)
• NBGM3 (New Bedford Harbor)
• ATGM1 (Bar Harbor )

[abkfenris]

I think the observations were right, but forecasts and predictions were off: https://app.asana.com/0/1208442266713400/1209018730783161

I've gotten at least part of the way on drawing NAVD88 on the front end now.