Glossary
Plain-words definitions for the terms on the map. A front is the edge where two bodies of water meet, an eddy is a spinning body of water, and the thermocline is the depth where the water turns cold. The technical names you might hear are explained too.
More detail
Front: what captains call a break, a rip or an edge. It is warm water against cool, clear against green, or salty against fresh. A front layer shows how fast the water changes over distance, not the value itself. The Front Intensity layers shade how sharp the change is; the Front Edges layers draw only the line.
Eddy: often tens of miles across. A warm-core eddy has warm water at its center, and the sea surface there stands high; a cold-core eddy has cool water at its center, and the surface there sits low. The water runs fastest around the rim.
Thermocline: below the warm surface water the temperature drops quickly, and that step is the thermocline. The Thermocline Depth layer shows how far down it sits, in feet.
Mixed layer: the warm surface water above the thermocline. "How deep the surface water is mixed" in a species map article means how far down this warm water reaches.
Salinity: how salty the water is. Fresh river water meeting blue ocean water makes an edge, and the salinity layers show it.
Chlorophyll: the green pigment of the microscopic plants drifting in the ocean, which a satellite reads as how green the water is.
Phytoplankton: those microscopic drifting plants themselves. Phytoplankton and chlorophyll maps look alike and are not the same thing.
Water clarity: how far down light reaches. The two clarity layers come from the same satellite readings of the water's color.
Sea surface height: how high the ocean surface stands. Currents run along its contours.
Sea level anomaly: how far the sea surface sits above or below its normal height, a quick way to find eddies. The Sea Level Anomaly and SLA (DUACS) layers show it.
Convergence: where surface water is pushed together. That is where weed, foam and bait collect.
Retention: slack water, slow enough that drifting things such as weed and bait tend to stay put.
Model and measurement: a measurement comes from a satellite that looked at the water, and many measurements go blank under cloud. A model is a computer simulation of the ocean, so it has no cloud holes. The Observed tab holds the measurements, and the Forecast tab holds the models.
Gap-free: a layer whose cloud holes are filled in by estimate.
Composite: several satellite looks merged into one picture.
Skin and bulk temperature: a satellite reads the very top of the water, the skin, so on a calm sunny afternoon it can differ from your transducer.
Layer: one map of one thing, such as surface temperature, drawn over the chart. You pick layers from the Data Layers list.
Layer Settings: where you change how a layer is drawn. Colormap is the set of colors, Range is the span of values the colors are spread across, and Opacity is how much of the chart shows through.
Frame: one picture of a layer at one moment. Some layers have one frame a day and some have one every five minutes.
Time bar: the slider along the bottom of the map that moves through time, frame by frame. A dimmed stop on the website, or a hollow dot on the iPhone app, means that layer has no data for that moment.
Region: one of the five areas Bite Intel covers: the Gulf of America, three along the East Coast, and Baja.
Species map: a map whose score is a 0 to 100 habitat match for one species. You open it from the Bite Intel button along the bottom of the map. The app marks species maps as in development.
Habitat match: how well the water at a spot suits that species, read from the water data. Nothing in it observes a fish.
Solunar windows: the day's feeding windows worked out from the position of the moon. They are shown for information and are not part of any species map.
Logbook: where the app keeps the trips you record and the catches you log.
The names you might hear
| If you hear | It means |
|---|---|
| HYCOM | HYCOM (U.S. Navy model), the ocean forecast model behind most of the Forecast tab: water temperature, salinity, currents, sea surface height and the layers worked out from those. The chlorophyll, plankton and oxygen forecasts come from the European Copernicus model instead |
| The Forecast tab | Where the HYCOM layers live. It runs ahead of today |
| The Observed tab | Satellites: what was actually there, with cloud holes where the view was blocked |
| GOES-19 | The weather satellite behind the hourly temperature maps and the five-minute ones over the Gulf of America, the East Coast and Baja |
| ACSPO | NOAA's daily satellite temperature product, built from several polar satellites |
| MUR | NASA's daily temperature map, with the cloud holes filled in |
| DUACS | The satellite measurement of sea surface height, on the Observed tab |
| GlobCurrent | The satellite-derived current speed behind Currents (GlobCurrent), on the Observed tab |
| Copernicus or CMEMS | The European service behind the chlorophyll, plankton and oxygen layers |
| SMAP | The satellite behind the fresher of the two observed salinity layers |
| GEBCO | The seafloor depth dataset behind the bathymetry layers |
| UTC (also written "Z", as in 12Z) | The world's reference clock, used in provider schedules |
| FSLE | The calculation behind the two drift layers. The Surface Convergence layer is a different calculation, worked out from HYCOM's currents |
The numbers
| What "region" means | One of the five areas Bite Intel covers: the Gulf of America, three along the East Coast, and Baja |
| What a front layer measures | How fast a property changes over distance, not its value |
| Which chlorophyll layer is coastal only | Chlorophyll (OLCI ~600m), within about 108 nautical miles of a coast |