Unavailable is an answer: handling missing wind information

Missing and stale describe different questions and can occur together. A field may be absent from a response, while the response itself may also be older than the freshness policy allows. Missing means the needed information is unavailable in the record being examined; it does not prove that the provider never supplied it. Stale means it is no longer current for the intended use under the applicable policy. Neither state should be silently displayed as a current numerical value.

Start by inspecting the actual response and its metadata. Is the relevant variable present? Does the series include the intended valid time? Was retrieval successful? What source and update information is available? These questions separate an omitted field from an unavailable response or an unclear timestamp. Do not invent a cause for a gap. An absent value alone does not prove a provider outage, an expired measurement or a normal forecast-production interval.

The MET Norway documentation describes differences in available variables by region and forecast series. A gust field may therefore be absent even when mean wind is present. The practical reporting rule is to mark gust information unavailable in that response. Do not estimate it solely to complete a chart. This rule is an editorial interpretation of missing data, not a quoted provider command that every absent gust must be fabricated or suppressed in a particular software method.

Missing data and model limits should remain separate. MET Norway warns about wind speed in complex topography with global forecasts. A present field can still have that limitation. The coordinate identifies the requested place but does not establish a direct measurement there. Read the forecast as model output and retain its supported scope. Do not assume that every value is a grid-cell average or that an available value is necessarily accurate at a particular site.

For MET Norway wind_speed, the documented definition is metres per second, a ten-minute average, at ten metres above ground. State those properties for that field rather than applying them to all providers. Units, reference height and averaging period are separate parts of the definition. A display that shows only a number loses useful context. Missing units should be treated as missing context, not filled from habit when the underlying dataset is uncertain.

Similarly, wind direction is defined as the direction the wind comes from, not the direction it blows toward. Zero degrees is north, ninety is east, one hundred eighty is south, and two hundred seventy is west. This convention is standard in meteorology but can be a source of confusion if not explicitly handled. A reader that assumes the direction indicates the destination of the wind will produce incorrect vector calculations. The source facts clearly state that wind_from_direction is the direction the wind comes from. This distinction is basic to any vector-based analysis of wind data. Misinterpreting this label leads to errors that are not easily detectable without domain knowledge.

Locationforecast supplies predictions for coordinates, not wind measurements made at the requested site. Its documentation describes a forecast horizon of the next nine days and more variables for the Nordic region. Inspect the actual response before deciding what is available for a particular time. A forecast can concern the present period while still being a forecast rather than an observation. Keep that status visible rather than calling it live measured wind.

Additionally, the service is not suitable for forecasts above ground level. Aviation has a different service for this purpose. A reader that attempts to use ground-level wind forecasts for aviation purposes is operating outside the intended scope of the data. The wind profile changes with altitude, and ground-level values do not represent conditions at flight levels. This limitation is a hard boundary of the service. The reader must recognize that the data is specific to the surface or near-surface layer and must not extrapolate it to other altitudes without additional data sources. This scope limitation is a key factor in determining the applicability of the wind information.

In a JSON response, an absent key, an explicit null and an empty string are different representations. Their meaning depends on the source schema. Inspect that schema rather than assigning a universal meaning to each form. For a field expected to contain a number, a blank or missing representation does not establish zero. A practical review should record which representation occurred and whether the documentation explains it.

A zero wind value is not evidence of a missing field merely because the place is associated with strong winds. Check whether zero was explicitly supplied, whether parsing retained it correctly and what quantity it describes. Do not replace it with a more plausible-looking value from expectation. If it raises a quality question, preserve the source record and seek supporting evidence. The number alone does not identify a sensor fault, forecast failure or calm observation.

Another practical question is how to handle unit conversions. If an application requires wind speed in kilometres per hour, the reader must convert from metres per second. This conversion is straightforward, but it must be applied consistently. The reader must ensure that the conversion is applied to the correct variable and that the unit label is updated to reflect the new unit. Failing to update the unit label leads to ambiguity. The reader must maintain a clear record of the units used at each stage of the processing pipeline. This traceability is essential for debugging and for ensuring that the data is interpreted correctly by other readers.

Consider a hypothetical scenario where a reader requests wind data for a coordinate in a region where gust values are not available. The reader receives a JSON response that includes wind speed and wind direction, but no gust field. The correct handling is to report the wind speed and direction, and to explicitly state that gust data is unavailable. The reader must not estimate the gust value based on the wind speed. This would be an invention of data, which is prohibited. The reader's output should reflect the actual availability of the data, not a fabricated completeness. This scenario illustrates the importance of respecting the boundaries of the data source.

Consider another hypothetical review in which the intended valid time is not present in the retrieved series. The supported conclusion is that the response does not supply the needed forecast point. Check the service documentation and response status before describing why. Do not predict that an out-of-horizon request must return a particular empty response or classify every gap as normal. Report the missing time and identify what further source or decision is needed.

• Gusts and turbulence
• Averaging periods: 10-minute, 1-hour and gust
• Siting and exposure: why location changes the reading
• Anemometers: cups, vanes, sonics and lidar
• UNKNOWN versus zero