Description
Report the position of the highest and lowest winds, respectively, from this sounding.
The REL group is defined in the NHOP as “the time and location of the highest (in altitude) wind reported in the temp drop message.” Aspen inspects the wind speed and latitude data series and finds the highest (earliest) point that contains valid data in both. This currently assumes that wind speed and wind direction are paired series (i.e. if one value is present the other must also be present), and so are latitude and longitude. Once a time is found, the REL level is filled in with that time’s pressure, wind speed, wind direction, latitude, and longitude values.
When aircraft data is present and not ignored in a sounding, Aspen prepends the aircraft launch observation to each sonde data series. This means that if aircraft position and winds information is present in QC data, it will be used as the REL location. If aircraft data is missing or ignored, the position reported in the REL group will be the highest data from the sonde.
The SPG group is defined in the NHOP as “the time and location of the lowest (in altitude) wind reported in the temp drop message.” Aspen inspects the wind speed and latitude data series to find the lowest (latest) point that contains valid data in both. Once a time is found, the REL level is filled in with that time’s pressure, wind speed, wind direction, latitude, and longitude values.
Source
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