PORP key terms

A NOAA-led effort that operates coastal observing systems delivering real-time winds, water levels, currents, waves, and visibility to mariners and other users through a national network of local installations.

A locally organized group of port authorities, pilots, and maritime stakeholders that helps define requirements, fund operations, and guide priorities for a regional PORTS installation.

The entity responsible for day-to-day operation of a PORTS installation, including sensor upkeep, data transmission, quality checks, and coordination with the national program office.

A facilitated meeting where users such as pilots, port staff, and emergency managers state measurement needs, thresholds, and product formats that shape system design and priorities.

A written commitment defining expected data availability, latency, and maintenance response times between the operating entity and data users or funding partners.

The elapsed time between a sensor sampling a value and that value becoming available to end users, a key performance measure for real-time navigation products.

Controlled documentation and tracking of hardware settings, software versions, sensor locations, and calibration constants so that system changes are recorded and reproducible.

A documented record tracing who handled a sample, instrument, or data set, and when, used to preserve defensibility of measurements and audits.

An instrument that measures water velocity through the water column by transmitting sound pulses and analyzing the Doppler shift of echoes from suspended particles.

The vertical size of each measurement bin along an acoustic Doppler current profiler beam, set by the user and traded off against resolution and noise.

Biased velocity readings near the surface or bottom caused by acoustic energy from beam side lobes reflecting off boundaries; mitigated by blanking cells or processing choices.

A point-measurement instrument using multiple acoustic beams to resolve three-dimensional velocity in a small sampling volume, often used for turbulence and shallow-water studies.

A non-contact gauge that measures water surface height by timing sound pulses traveling between a transducer and the water surface, compensated for air temperature and humidity.

A submerged sensor converting hydrostatic pressure into a water depth value; requires barometric compensation and attention to drift and biofouling.

The correction applied to subsurface pressure readings that removes the effect of atmospheric pressure so that only the water column contribution remains.

A fixed graduated scale read visually to provide an independent check on water level and to confirm the vertical reference of a sensor.

A permanently marked, surveyed reference point of known elevation used to tie water level sensors and staff gauges into a stable vertical datum network.

A precise field procedure that determines elevation differences between benchmarks and sensors, establishing and verifying the datum relationship for water level records.

A reference surface such as Mean Lower Low Water derived from long-term tide observations, used as the zero plane for charted depths and water level products.

The average of the lower of the two daily low waters over a specified 19-year period, serving as the chart datum for most U.S. nautical charts.

The vertical difference between two reference surfaces, such as between a sensor's local zero and a chart datum, applied when converting raw readings to published values.

A forecast of future water levels computed from harmonic constituents derived from historical observations, distinct from observed or nowcast values.

An amplitude and phase pair describing one periodic astronomical tide component, which summed with others reproduces the predicted tide curve.

The abnormal rise of water above predicted tide driven by wind and low pressure, a major source of water level forecast error and coastal flooding risk.

The difference between observed water level and predicted tide, revealing surge, seiche, or river flow effects that predictions alone do not capture.

A continuously updated stream of observations delivered from sensors to users with minimal delay, typically over network or satellite links.

The communication path carrying sensor data from a remote station to a processing center, using cellular, satellite, radio, or wired connections.

On-station memory that holds observations when communications fail and transmits them once the link is restored, preventing data gaps.

The process of loading delayed or recovered observations into the archive after an outage so the historical record becomes complete.

A coded descriptor attached to each observation indicating its assessed reliability, such as good, questionable, bad, or missing.

A real-time test that flags values falling outside physically plausible bounds set for a sensor, catching gross errors before data are published.

A QC procedure comparing a value with its neighbors to detect implausible jumps, flagging transient errors such as electrical noise or dropped samples.

A check identifying prolonged periods of identical readings that suggest a stuck sensor or failed communication rather than real environmental steadiness.

Structured documentation of sensor type, position, elevation, datum, and deployment history for a station, essential for interpreting and reprocessing data.

A document recording an instrument's comparison against a reference standard, including date, method, and correction factors applied to its output.

A planned calendar of inspections, cleaning, and calibration tasks designed to keep sensors accurate and reduce unplanned outages.

The accumulation of algae, barnacles, and other organisms on submerged sensors that degrades optical and acoustic measurements and requires periodic cleaning.

A tailored display or derived value, such as a current nowcast or visibility index, built for a specific operational audience from underlying observations.

A pre-task review that identifies hazards, controls, and required protective equipment before field work such as buoy servicing or dock repairs.

A rehearsed rescue procedure practiced by field crews so that recovery actions are rapid and coordinated during an actual fall into the water.

Wearable buoyancy equipment required during on-water field operations to keep personnel afloat and visible if they enter the water unexpectedly.