bin.name = "standard_knowledge"
args = ["qc", "get", "sea_surface_height_above_geopotential_datum", "gulf_of_maine"]
stdout = """
Gulf of Maine (gulf_of_maine)
Water level tests for stations in the Gulf of Maine developed by Hannah Baranes
Test types:
- Gross Range
- Spike
- Rate of Change
- Flat Line
Arguments:
- mhhw: Mean higher high water elevation in NAVD 88 meters (required)
- mllw: Mean lower low water elevation in NAVD 88 meters (required)
### Gross range test configuration for Gulf of Maine (not New England Shelf)
#### Suspect Limits
For stations with tidal datums (might not want this approach because it will always take a while to get tidal datums, and tidal datums change):
- Upper limit of range: MHHW + 6 ft
- Lower limit of range: MLLW – 4.5 ft
For stations without tidal datums:
- If there are no tidal datums because the station was just installed: use VDatum to get MHHW and MLLW relative to navd88_meters at a point close to the sensor, and use the same upper and lower limits
- Note: if it’s a station with river influence (like Bath), it might require some local expertise to set the limits. A solid approach is just taking the HW and LW measured over the course of the first week, and using something like HW + 10 ft and LW – 10 ft to be conservative
- If there are no tidal datums because the sensor bottoms out at low tide:
- Lower limit: Use the dry bottom elevation
- Upper limit: Use VDatum MHHW + 6 ft
#### Fail upper and lower limits
- Upper limit: distance to water is less than whatever the minimum sensing range is
- Lower limit: either hard bottom (if it’s a site that bottoms out at LW, or if we have a depth measurement at the site), or distance to water = maximum of sensing range
#### Notes
Top recorded water levels, in ft MHHW (and year)
- Gulf of Maine
- Eastport: 5.07 (2020)
- Bar Harbor: 4.43 (2024)
- Portland: 4.67 (2024)
- Boston: 4.89 (2018)
- New England Shelf
- Chatham, MA: 4.28 (2014)
- Newport, RI: 9.45 (1938)
-New London, CT: 7.53 (1938)
Lowest navd88_meters
- Eastport: -3.46 ft MLLW (this will have the largest variability)
### Rate of change test. Input as a rate.
- Suspect: 0.75 feet per 6 minutes
- Fail: 1 foot per 6 minutes
Rationale: max rate of change from tides in Eastport is 5.3 ft per hour (midtide on 1/13/2024), or ~0.5 ft per 6 minutes. Add 0.25 feet for a sustained wind-driven increase in water level.
May want to adjust this so it’s dependent on tidal range
### Spike test: Input as a magnitude that’s checked across a measurement and the two adjacent measurements.
Maybe default to same as rate of change test?
### Flat line test: If there’s some lack of variance over some amount of time, mark as suspect/fail
Suspect/Fail = how long do subsequent values stay within that threshold before it’s considered flat? (input as a time)
For example, if all measurements over the past 4 hours are within 10 cm of each other, fail the flatline test (then tolerance = 10 cm, and time = 4 hours)
When a sensor flatlines, the system voltage and temperature sensor may still be causing variation
Let’s start with 0.1 feet over 2 hours for suspect, and 0.1 feet over 3 hours for fail.
Rationale: During neap tides in Portland, you could see as little as +/- 0.25 ft per hour of variation in the 2 hours around slack tide (HW or LW)
"""