PORP flashcards
PORP · Build recall with a focused review session.
32 cards. Read the term and the definition here. The deck at the top of this page is optional.
- PORTS program purpose
- A NOAA program delivering real-time coastal observations and predictions for safe navigation, port efficiency, and environmental decision-making, operated through regional partners and local user groups.
- PORTS user working group
- Local stakeholders such as pilots, port authorities, and the Coast Guard who define the operational thresholds and products a PORTS system must deliver before siting is chosen.
- Data availability metric
- Percent valid records divided by expected records over a period, multiplied by 100, excluding documented outages; a core PORTS performance measure.
- Acoustic water level sensor
- Measures the round-trip travel time of a sound pulse to the water surface through a stilling well or orifice, referenced to a surveyed benchmark.
- Bottom-mounted ADCP
- Upward-looking acoustic Doppler current profiler that measures velocity in depth bins using Doppler shift from scatterers, producing a current profile.
- Sonic anemometer
- Measures wind speed and direction from travel times of sound pulses between transducer pairs; no moving parts, but prone to icing and salt fouling.
- Significant wave height Hm0
- Four times the square root of the variance of the surface elevation spectrum (m0); a spectral measure of wave height from a wave record.
- Forward-scatter visibility sensor
- Estimates visibility by measuring light scattered from an air sample at a known angle; output in nautical miles or meters, calibrated to local conditions.
- GOES DCP telemetry
- One-way satellite data collection with fixed time slots and low bandwidth; no acknowledgement, so dataloggers must buffer and retransmit records.
- Store-and-forward logging
- Dataloggers keep records locally during communications outages and transmit the backlog when the link returns, preventing data gaps.
- UTC timestamp rule
- Every observation carries a UTC timestamp plus station and sensor identifiers so records from different systems can be joined and audited.
- Solar power budget
- Panel and battery sizing based on worst-case winter insolation, load, and consecutive cloudy days, with a depth-of-discharge margin.
- Real-time QC philosophy
- Automated, conservative checks flag suspect values rather than deleting them, so downstream users retain the data and its quality context.
- Spike test
- Compares a value to the median of neighboring values; a large deviation flags a possible outlier for review without removing the record.
- Flat-line test
- Detects a sensor reporting an unchanging value over a period longer than physically plausible, indicating a stuck or failed sensor.
- Tidal residual check
- Compares observed water level to predicted tide; large residuals flag surge, runoff, seiche, or sensor drift for review.
- Delayed-mode QA/QC
- Manual review after the fact using reference comparisons, benchmark leveling, and sensor histories; can revise flags assigned in real time.
- MLLW chart datum
- Mean lower low water, the reference for charted depths in most U.S. waters, computed from the 19-year National Tidal Datum Epoch.
- National Tidal Datum Epoch
- A 19-year period of hourly water level heights used to compute tidal datums; the current epoch is 1983–2001.
- Datum transfer
- Deriving datums at a short-record site by comparison to a long-term control station; error grows as the short record shortens.
- Mean range of tide
- Mean high water minus mean lower low water? No: mean range is MHW minus MLLW is diurnal; mean range is MHW minus MLW.
- Harmonic tide prediction
- Summing constituent amplitudes and phase arguments (M2, S2, N2, K1, O1, etc.) fitted to observed heights to predict future water levels.
- ADCP earth coordinates
- Velocity transformed from beam or instrument frame to east-north-up, with magnetic declination applied so directions are true.
- Current direction convention
- State whether direction is the direction toward which water flows or the set; report in degrees true and specify the convention in metadata.
- Wind direction convention
- Meteorological convention: the direction the wind blows from, in degrees true, at a stated reference height such as 10 meters.
- Pressure wave attenuation
- Bottom pressure sensors underestimate high-frequency waves with depth; a frequency-dependent correction must be applied before computing spectra.
- Differential leveling
- Surveying sensor height relative to a stable benchmark; an unresolved benchmark error propagates directly into all reported water levels.
- Troubleshooting order
- Verify power, then datalogger clock and program, then local sensor output, then telemetry, then central ingest, to isolate the fault stage.
- Change control record
- Documentation of any sensor swap, relocation, or program change with effective date and reason, kept in station metadata.
- Storm surge definition
- The residual water level above the predicted astronomical tide during a storm, not the total observed water level.
- Product latency tiers
- Real-time (minutes), near-real-time, and archived delayed-mode data; users must know which tier a product represents.
- Job hazard analysis
- A written pre-task review of field hazards, controls, and emergency contacts required before over-water or lifting operations begin.