Overview of the Upper Air Data Continuity Study: An Intercomparison between the National Weather Service's Legacy Upper Air System and the new Radiosonde Replacement System to asses True Climatic Variation

Overview of the Upper Air Data Continuity Study: An Intercomparison between the National Weather Service's Legacy Upper Air System and the new Radiosonde Replacement System to asses True Climatic Variation

Katie Webster and Ryan N. Brown CyberData Technologies, Inc. 43741 Weather Service Road Sterling, VA 20166 E-mail: Katie.Craven@noaa.gov, Ryan.Brown@noaa.gov

Jim Fitzgibbon National Weather Service, Office of Operational Systems 43741 Weather Service Road Sterling, VA 20166 E-mail:James.Fitzgibbon@noaa.gov

Since the late 1980s, the Microcomputer Automatic Radiotheodolite (MicroART) system has been used to conduct upper air soundings at the National Weather Service (NWS) upper air sites. Recent types of radiosondes flown in the legacy NWS network include the Vaisala RS80® and the Sippican B2®. These instruments have been nearly phased out of the network and replaced by Global Positioning System (GPS) radiosondes. These GPS radiosondes significantly impact operations because of changes in temperature, pressure, and relative humidity sensor technologies. As a result of these changes and their potential impact on the long-term upper air climatic records, NWS directive NDSPD 10-2101 requires a credible data continuity study be conducted. The requirements for this directive are derived from requests received from the day-to-day data users, the U.S. climatological services and academia. In order to satisfy this directive, the NWS is conducting an Upper Air Data Continuity Study (DCS). This study can be used to assist in determining what component of the total change seen in the climatic data is a result of true climatic variation and what component is related to a change in sensor technology, algorithm changes, and new procedures. The legacy upper air system (MicroART) and the new Radiosonde Replacement System (RRS) will be operated in tandem as dual flights are flown to accomplish these necessary comparisons. The NWS plans to meet these goals through the selection of four upper air sites which are diverse in meteorological and climatological conditions: Sterling, VA, Caribou, ME, Barrow, AK, and Barrigada, Guam. Approximately 120 dual flights will be conducted at each of the aforementioned sites using the Sippican B2® (MicroART system) and the Vaisala RS92-NGP® radiosondes (RRS). This paper will discuss the test process and a first look at an intercomparsion of the data sets.