Unexplained Discontinuity in the U.S. Radiosonde Temperature Data. Part II: Stratosphere

The second part of this two-part article discusses the differences between observations taken at 0000 and 1200 UTC, particularly in the stratosphere, by the Vaisala RS80-57H radiosondes that are integrated within the National Weather Service's (NWS's) Micro-ART system. There are large maxima in the horizontal distributions of the monthly time means of the 0000/1200 UTC temperature and height differences over the central United States that are absent over Canada. These maxima are as large as 5 K and 150 m at 10 hPa. Data analysis shows that the 0000/1200 UTC differences are largely artificial, especially over the central United States. They originate in the postprocessing software at observing stations, thus confirming the findings in Part I.