NCEP is frequently rejecting upper-air data from a particular station. Why is this happening and what can station staff do to correct the problem?
Here are some possible causes and corrective actions : (a) Defective radiosondes or ground equipment. The NWS upper-air network uses about 75,000 radiosondes each year. Some of them will be defective. Likewise, the ground tracking equipment is old and prone to failure or misalignment. Station staff should check to see if there is a correlation between the date when the data rejections started and when a new shipment of radiosondes was first used. If there is clearly a match, the NWS Regional Upper-air Program Manager should be contacted as soon as possible. If frequent winds errors are occurring, the automated radiotheodolite (ART) should be checked for correct alignment. (b) Solar/IR radiation on the radiosonde temperature sensor. Solar/IR radiation can affect accuracy of the temperature data (and height data) at altitudes typically above 200 hPa. Corrections are applied to the data, but sometimes they don’t work adequately. If temperature/height rejections are mostly above 200 hPa an
