What Wind Directional Shear measures
Directional shear tracks turning between two wind-from bearings. Wrapping the difference prevents a change across north from being mistaken for almost a full circle.
The Wind Directional Shear calculation begins with lower wind-from direction, lower height, upper wind-from direction, upper height. Mark each value as observed, averaged, assumed, or derived so the result keeps a traceable meaning.
Formula and sign convention for Wind Directional Shear
The working relationship is Wrapped Δdirection × 1000 ÷ Δheight. Positive values indicate clockwise turning along the chosen shortest path as height increases; negative values indicate counterclockwise turning. A 180° difference is inherently sign-ambiguous.
Angles are interpreted in degrees and normalized around the compass where applicable. Keep the stated wind-from and motion-toward conventions attached to every Wind Directional Shear result.
From Wind Directional Shear, continue with the related Vertical Wind Speed Shear Calculator.
From Wind Directional Shear, continue with the related Crosswind Component Calculator.
A checked example
From 350° at 100 m to 10° at 1100 m, the shortest change is +20° over 1 km, or +20°/km.
The page loads those demonstration values. Recalculate the Wind Directional Shear example independently before substituting field observations, and keep extra digits until the last reporting step.
From Wind Directional Shear, continue with the related Wind Vector Components Calculator.
Preparing compatible observations
Use directions from non-calm winds at compatible times and heights. Direction becomes unstable near calm, so a large angular change may have little vector significance.
Record location, timestamp, time zone, sensor height, exposure, averaging period, speed unit, and direction reference beside Wind Directional Shear. These details often explain disagreement better than additional decimal places.
Reading the result
The result states degrees of bearing change per kilometre, not change in wind speed. Full vector shear requires both component differences.
Treat the displayed answer as a result for the exact entered state. Comparing Wind Directional Shear across sites or times requires aligned measurement and averaging conventions.
Boundary and sanity checks
Identical bearings give zero. Crossing 360° is wrapped correctly; exactly opposite bearings require an explicit sign convention.
For Wind Directional Shear, change one input at a time and predict the direction of change before calculating again. An unexpected response can reveal reversed bearings, incompatible heights, mismatched intervals, or speed-unit mistakes.
Where the calculation stops
Two endpoints cannot reveal curved or reversing profiles inside the layer. Meteorological dynamics may use veering and backing terminology with hemisphere and context.
Wind Directional Shear supplies transparent arithmetic, not a weather forecast, warning, engineering certification, navigation instruction, or authority to operate in hazardous conditions.
Uncertainty and sensitivity
Vary the least certain Wind Directional Shear input across a credible range while holding the others fixed. Report how far the output moves instead of implying that calculator precision equals atmospheric accuracy.
This sensitivity check is not a probability interval. It tests the chosen formula and entries; it cannot include every effect omitted from the Wind Directional Shear model.
Direction, speed, and time bases
Wind direction may be instantaneous, vector-averaged, or coded after calm filtering, while speed may be a gust or a scalar mean. Wind Directional Shear is defensible only when those bases fit together.
If a source rounds compass bearings or speed classes, preserve the original coding. Do not invent precision before using the values in Wrapped Δdirection × 1000 ÷ Δheight.
Calm and near-calm handling
Near calm, direction can change sharply because tiny component noise dominates the bearing. A Wind Directional Shear workflow should retain the speed and any station calm code instead of overinterpreting the angle.
If calm records are excluded, document that filter and denominator. The choice can change both directional summaries and comparisons based on Wind Directional Shear.
Keeping an auditable record
Save the raw entries, conversions, formula version, full-precision output, rounded result, and quality flags for Wind Directional Shear. A reviewer should be able to reconstruct the answer without guessing conventions.
When a source value or method changes, create a dated revision rather than overwriting the earlier Wind Directional Shear record. Explain whether the change corrects data or explores a scenario.
Using the output elsewhere
Transfer the unrounded shortest-path directional shear with its unit, sign, source time, and reference frame. Downstream calculations can fail quietly when a wind-from bearing is treated as motion-toward.
A single Wind Directional Shear answer describes one defined calculation. Trends and climatologies require repeated records plus explicit rules for gaps, calm observations, changes in exposure, and weighting.
Common data-quality traps
Typical Wind Directional Shear errors include mixing knots with metres per second, using magnetic and true north together, pairing a gust with an unrelated mean, or combining observations from different heights.
Reject physically impossible Wind Directional Shear cross-field combinations rather than forcing an answer. The calculator checks its stated domains, but source metadata and representativeness still require human review.
Questions about the result
Are wind directions entered as from or toward bearings?
In Wind Directional Shear, wind directions are meteorological from bearings unless a field explicitly says that a heading or observer motion points toward a direction.
How can I verify the Wind Directional Shear result?
Repeat Wrapped Δdirection × 1000 ÷ Δheight from the recorded inputs, then test the example and a physically meaningful boundary case.
Can I enter forecast values?
Yes, as a clearly labeled scenario. The Wind Directional Shear page does not fetch, validate, or issue a forecast.
Why might another source disagree?
Another Wind Directional Shear source may use different units, averaging periods, heights, direction conventions, coefficients, thresholds, calm rules, or rounding.
Does this calculator establish a safe operating limit?
No. Wind Directional Shear is arithmetic and does not replace current warnings, procedures, design standards, or qualified operational judgment.
How should I round the answer?
Keep full precision through Wind Directional Shear, then round no more finely than the least precise wind input and intended use support.
What does Wind Directional Shear report?
It reports shortest-path directional shear using the displayed formula, units, direction convention, and entered values.