Inertial Circle Radius Latitude Calculator
Ideal f-plane inertial circle radius; equatorial f=0 rejected, not actual drifter prediction.
Description
Estimate an ideal inertial-circle radius from speed and nonzero latitude.
An ideal inertial-circle radius relates speed to the magnitude of the local Coriolis parameter. It is a simplified scale estimate for free motion in a local rotating model.
When to use this tool
Estimate an ideal inertial-circle radius from speed and nonzero latitude. Use it when the input measurements and conventions below match the operation you need.
- Prepare speedMPerS, latitudeDegrees, respecting the measurement basis and boundaries below.
- Compare the worked example with your intended operation before reusing its result.
How to use the tool and how it works
- Enter every field in the input table using the stated units and exact supported selector spelling where applicable.
- Run the tool. Correct input errors before interpreting an output.
- Read the result fields below; use accompanying flags and the stated sign, boundary or model convention when interpreting a number.
Speed must be nonnegative and latitude nonzero within -90 to 90 degrees. The tool computes f from the fixed Earth rotation rate and returns speed divided by the absolute value of f.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| speedMPerS | Speed m per s. Meters per second. | Finite number; zero or greater |
| latitudeDegrees | Latitude degrees. Degrees. | Finite number; from -90 to 90 inclusive |
| Output field | Interpretation |
|---|---|
| result | Object containing the following named result fields. |
| result.radiusM | Radius m; use the stated units and sign convention. |
{
"input": {
"speedMPerS": 1,
"latitudeDegrees": 30
},
"output": {
"result": {
"radiusM": 13713.442533476227
}
}
}Limitations and assumptions
- The model becomes unbounded near the equator. Pressure gradients, friction, background current and changes in latitude along a trajectory are not included.
- Every declared field is required and unexpected fields are rejected. Numeric inputs must be finite; input errors are distinct from a valid false result or an explicitly qualified output.
- Extremely large inputs and nonfinite or excessively large outputs are rejected. List positions reported by the tool use zero-based indices unless stated otherwise.
Alternative or Complementary methods
Compare the result with independently checked observations or a model that covers the omitted dynamics. Use compatible frames, units and sampling conventions when carrying the value into another calculation. Compare the scope of the nearby tools below before substituting one.
References
Similar or alternative tools
- Inertial Period F Latitude Calculator
Ideal f-plane inertial period in seconds; signed hemisphere does not change period, equator rejected.
- mooring watch circle radius drag
A mooring watch circle summarizes the observed horizontal excursion of a moored object.