This section contains methods for the general project.
Goals for project WKN7S8803
This section contains a progress report on the general project.
Memo Text for project WKN7S8803
Weather station component sensors and recorders were ordered and received. Sensor
systems were assembled and interfaced with data loggers. An extensive bench program
of sensor quality control and trouble-shooting was implemented. Instrument shelters
were constructed. Sensor platforms were erected in the field. Data management and
maintenance protocols were developed. Sensors were installed in the field in winter
1989. Routine data collection began in spring 1989.
Meteorological stations will provide continuous monitoring of wind speed and direction,
temperature, humidity, pressure, precipitation, short wave radiation, and photosynthetically
active radiation. All parameters, except pressure will be observed with automated
sensors and the data will be logged by a Campbell data logger and recorded on a cassette
tape. Due to high cost of the sensor, atmospheric pressure will be sensed by an analog
device with data recorded on paper charts and digitized for archival storage. Power
will be provided by a 12V lead-acid car battery. The power supply needs to be fully
contained within the sensor shelter to minimize the exposure of the sensor array to
lightening strikes. Propane gas heaters (a simple pilot light burner) may be necessary
to maintain the data loggers at operating temperature during the winter months.
Tide gages component sensors and recorders were ordered. The Phillips Creek tide station
was activated in summer 1988. The Machipongo Station gage will be activated in spring
The tide gages consist of Stevens type 71A water level recorders providing a long-period
paper record of water level fluctuations. No power is required to run the Stevens
recorder. A float in a stilling well will be used as the sensor at the relatively
stable, protected Phillips Creek monitoring site. A bubbling orifice and servo-manometer
will be used as the water level sensor at the Machipongo Station. Nitrogen is slowly
bled out of a compressed gas tank into the water column, and changes in the depth
of water areas read as changes in the gas pressure needed to maintain a constant rate
of gas flow. The bubbling orifice and servo-manometer configuration is expected to
mitigate the effects of high siltation rates at the north end of Hog Island. The Stevens
recorder and the servo-manometer will be located inside of the Machipongo Station
on Hog Island.
Both the tidal and meteorological instrumentation will be visited once a week for
maintenance and data collection.
This section contains specific methods for this dataset.
Data were automatically collected every 12 minutes using a variety of technologies.
Stevens bubble gauges were used from 1991-1994 when they were replaced by Metritape
tape loggers. These were then replaced with vented pressure sensors. Starting in 2011
the tide gauges were replaced with radar sensors that are suspended above the water.
Starting in 2015 some stations were upgraded to collect 6-minute data to facilitate
sharing with NOAA.
The Oyster station is best tied to external datums. The dock to which it was attached
was constructed to be 1.64 meters (5 feet) above MSL. The radar gauge was calibrated
using a staff gauge attached to the dock a measured distance below the top.
Due to changes in the landscape caused by accretion of Hog Island a sequence of gauges
were used, starting with a Stevens bubble gauge attached to a pole driven into the
lagoon. However repeated problems with the pole being ripped out by ice led to the
use of a metritape gauge attached to the dock of the Machipongo Station. During this
time a GPS benchmark using NAVD88 to the nearest 1/10 of a foot was established on
the dock of the Machipongo Station. This was used to place a staff gauge (i.e.,ruler)
on the Machipongo station dock.However, this location did not have deep enough water,
so subsequently the Hog3 station was established on a pole in a tidal creek approximately
50 meters upstream from the Machipongo Station. Using the water level to connect them,
a second staff gauge was added to a piling visible from the webcam on Machipongo Station
approximately 50 meters upstream from the dock at the site of the short-lived Hog3
gauge. Webcam images were used to related Hog3 measurements to the staff guage. When
the Hog4 gauge was established, the webcam was used to relate the level on the staff
near the Machipongo Station to the radar gauge at the Hog4 station and used to set
the 0-level on the Hog4 gauge.
The Redbank tide station used metritape and a series of pressure-guages, prior to
installation of a radar guage.