A Preliminary Discussion on the National Weather Service's Upper Air Data Continuity Study

In 2012, the National Weather Service (NWS) began a Data Continuity Study (DCS) comparing the legacy Upper Air System (MicroART) and the new Radiosonde Replacement System (RRS). NWS directive NDSPD 10-2101 required this test be conducted due to the improved radiosonde sensor technology associated with the RRS as the legacy system is phased out of the network. This study will be used to determine the amount of change introduced into the Upper Air network by transitioning to a new generation of radiosondes, algorithms, and procedures.

The NWS met the goals of this test early in 2014 by completing test flights at four upper air stations representing diverse meteorological and climatological conditions. The stations chosen were: Sterling, Virginia; Caribou, Maine; Barrow, Alaska; and Barrigada, Guam. At these locations the MicroART and the new RRS instruments were flown in tandem, twice per week, during standard synoptic observation times. Each site had the goal to achieve 120 flights reaching a minimum pressure of 30 hPa over a period of 70 weeks, barring supply and budget constraints. After each flight, all of the data was archived to the National Climatic Data Center for analysis. In addition, the Sterling Field Support Center in Sterling, Virginia had the ability to time-synchronize the releases between the systems which allowed the flights to be analyzed as a part of a time-paired series along with the pressure paired analysis. This allowed for a more in-depth comparison of the pressure, temperature, relative humidity, and height differences between the two different radiosondes to be conducted. This paper will discuss the procedures used to collect and analyze the DCS flight data from Sterling, Virginia and present results of the comparison data between the legacy MicroART system and the new RRS.