CTD Descend Rate Consistency Checker

Audit observed CTD signed descent rates and adjacent speed jumps against caller acquisition policy; flags do not automatically identify sensor lag or discard data.

Description

CTD acquisition quality can depend on descent-rate consistency.

CTD acquisition quality can depend on descent-rate consistency. Signed rates retain upward motion and stops.

Audit observed CTD signed descent rates and adjacent speed jumps against caller acquisition policy; flags do not automatically identify sensor lag or discard data.

When to use CTD Descend Rate Consistency Checker

Use this tool to audit observed CTD signed descent rates and adjacent speed jumps against caller acquisition policy; flags do not automatically identify sensor lag or discard data.

Gather the water, wave, current or profile observations and any supplied calibration constants. Confirm units and the stated coordinate and pressure conventions.

How to use CTD Descend Rate Consistency Checker and understand its results

Gather the water, wave, current or profile observations and any supplied calibration constants. Confirm units and the stated coordinate and pressure conventions.
Enter timesSeconds, depthsM, callerDescentSpeedBoundsMPerSecond, callerMaximumSpeedChangeMPerSecond using the field table and calculation rules, then run the tool.
Read intervalDescentSpeedsMPerSecond, outOfBandIntervalFlags, speedJumpFlags. The explanation below defines the units, signs, ordering and any flags or placeholder values.
If the tool reports an input issue, correct the values and run it again. Apply the stated assumptions when interpreting a successfully returned result.

Input field	Meaning	Value type; see rules below	Requirement
timesSeconds	Times seconds	list of number	Required
depthsM	Depths m	list of number	Required
callerDescentSpeedBoundsMPerSecond	Caller descent speed bounds m per second	list of number	Required
callerMaximumSpeedChangeMPerSecond	Caller maximum speed change m per second	number	Required

Align increasing seconds and nonnegative positive-down depths. Use two ordered signed speed bounds and nonnegative jump maximum. Flag rates strictly outside the inclusive band and adjacent rate changes strictly above the jump maximum.^[1]

Paired lists must be nonempty and have equal lengths. Each sequence checked for increasing order must contain at least two strictly increasing values.

rate = depth difference/time difference

Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.

Output field	Meaning	Value type
intervalDescentSpeedsMPerSecond	Interval descent speeds m per second	list of number
outOfBandIntervalFlags	Out of band interval flags	list of number
speedJumpFlags	Speed jump flags	list of number

json

{
  "input": {
    "timesSeconds": [
      0,
      1,
      2
    ],
    "depthsM": [
      0,
      1,
      5
    ],
    "callerDescentSpeedBoundsMPerSecond": [
      0.5,
      2
    ],
    "callerMaximumSpeedChangeMPerSecond": 2
  },
  "output": {
    "intervalDescentSpeedsMPerSecond": [
      1,
      4
    ],
    "outOfBandIntervalFlags": [
      0,
      1
    ],
    "speedJumpFlags": [
      1
    ]
  }
}

Limitations and assumptions

Flags neither diagnose sensor lag nor automatically discard data.

Numbers and computed results must be finite; overflow produces an error. Numeric lists are limited to 100,000 entries; the rules above may require smaller limits. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors.

Alternative or Complementary methods

Use XBT Fall Rate Equation Depth: Evaluate a caller-calibrated XBT quadratic fall-rate relation only within the supplied valid time horizon; no probe model coefficients or universal depth accuracy embedded. For a complementary task, use ADCP Bin Depth Transducer Offset: Compute ADCP beam-range bin centers on positive-down depths and caller bottom-clearance screen for a vertical instrument; side-lobe contamination and attitude corrections are not modeled.

References

CTD Descend Rate Consistency Checker — tool.io

Similar or alternative tools

XBT Fall Rate Equation Depth
Evaluate a caller-calibrated XBT quadratic fall-rate relation only within the supplied valid time horizon; no probe model coefficients or universal depth accuracy embedded.
ADCP Bin Depth Transducer Offset
Compute ADCP beam-range bin centers on positive-down depths and caller bottom-clearance screen for a vertical instrument; side-lobe contamination and attitude corrections are not modeled.