1. The Evolution and Development of the United States NOAA National Weather Service Universal Radiosonde Replacement System TECO 2005 World Meteorological Organization Bucharest, Romania TECO 2005 World Meteorological Organization Bucharest, Romania

2. History of NWS 50-Year Old Radiosonde System One radiosonde provider until 1986 Systems Upgrades –Minicomputer-based system to Microcomputer Automatic Radiotheodolite (MICROART) –Introduced Automatic Radiotheodolite Interface Card (ARTIC) ARTIC converts radiosonde analog signals to meteorological units One radiosonde provider until 1986 Systems Upgrades –Minicomputer-based system to Microcomputer Automatic Radiotheodolite (MICROART) –Introduced Automatic Radiotheodolite Interface Card (ARTIC) ARTIC converts radiosonde analog signals to meteorological units

3. History of Vendor Interface with Legacy System after ARTIC Introduction VIZ continued as radiosondes provider Space Data Division successfully interfaced radiosondes and became supplier in 1987. Vaisala interfaced NWS system via their decoder in 1985. Vaisala awarded contract in early 90s –Substituted Vaisala SPU-11 decoder for ARTIC –Modified RS80-56-H radiosonde VIZ continued as radiosondes provider Space Data Division successfully interfaced radiosondes and became supplier in 1987. Vaisala interfaced NWS system via their decoder in 1985. Vaisala awarded contract in early 90s –Substituted Vaisala SPU-11 decoder for ARTIC –Modified RS80-56-H radiosonde

4. Advantage of Multiple Radiosonde Provider Compatibility with Generic System Lower radiosonde cost Insurance against supply shortfalls Stimulates radiosonde improvement to maintain competitive edge Avoids replacement of entire system Lower radiosonde cost Insurance against supply shortfalls Stimulates radiosonde improvement to maintain competitive edge Avoids replacement of entire system

5. Network Replacement Considerations and Realities End-of-system life Winter RDF winds loss without transponder adjunct Multiple radiosonde providers Avoidance of vendor driven program changes –Loss of Omega systems –Loss of vendors, ground systems and radiosondes Space Data Division discontinued producing radiosondes and ground trackers Vaisala buyout of Air Inc and non-support of product line Vaisala programmed discontinuation of RS80 Series radiosonde and selected ground receivers in 2005 Anticipated loss of Loran-C Loss of OMEGA NAVAID system End-of-system life Winter RDF winds loss without transponder adjunct Multiple radiosonde providers Avoidance of vendor driven program changes –Loss of Omega systems –Loss of vendors, ground systems and radiosondes Space Data Division discontinued producing radiosondes and ground trackers Vaisala buyout of Air Inc and non-support of product line Vaisala programmed discontinuation of RS80 Series radiosonde and selected ground receivers in 2005 Anticipated loss of Loran-C Loss of OMEGA NAVAID system

6. Commercial Systems vs System Development Technology Management Corporation evaluated 5-systems against NWS requirements –Commercial systems did not support multiple vendor radiosondes interface with generic ground receiver and software. –Ground receivers did not support 250 Km range between radiosonde and ground receiver Technology Management Corporation evaluated 5-systems against NWS requirements –Commercial systems did not support multiple vendor radiosondes interface with generic ground receiver and software. –Ground receivers did not support 250 Km range between radiosonde and ground receiver

7. NCAR NEXUS Prototype Development Requirement –Multiple vendors support –403 and 1680 MHz radiosondes –Loran-C and OMEGA based Windfinding –One person operation –Semi-automated balloon launcher Requirement –Multiple vendors support –403 and 1680 MHz radiosondes –Loran-C and OMEGA based Windfinding –One person operation –Semi-automated balloon launcher

8. NEXUS Findings Not completely open architecture Required vendor specific decoders Minimal impact to system hardware and software with of new radiosondes Broad-band receiver maximized different use but enabled interference Obsolescence of Omega and projected phase-out of Loran-C Demonstrated generic system approach Not completely open architecture Required vendor specific decoders Minimal impact to system hardware and software with of new radiosondes Broad-band receiver maximized different use but enabled interference Obsolescence of Omega and projected phase-out of Loran-C Demonstrated generic system approach

9. Radiosonde Replacement System Telemetry Receiver System Radiosonde Signal Processing System Software and Workstation Surface Observation Instrumentation System 1680 MHz GPS radiosonde Telemetry Receiver System Radiosonde Signal Processing System Software and Workstation Surface Observation Instrumentation System 1680 MHz GPS radiosonde

10. NOAA NWS Radiosonde Replacement System System –GPS tracking antenna 1680 MHz GPS radiosonde New workstation and software Circular polarized radiosonde antenna Selectable narrow band frequency –Requirements Reduced radiofrequency spectrum Increased data availability and accuracy High resolution data for users System –GPS tracking antenna 1680 MHz GPS radiosonde New workstation and software Circular polarized radiosonde antenna Selectable narrow band frequency –Requirements Reduced radiofrequency spectrum Increased data availability and accuracy High resolution data for users

11. Radiosonde Replacement System Telemetry Receiving System available 1680 MHz GPS radiosondes –Intermet qualified –Sippican qualified and awarded contract Software undergoing OT&E Additional radiosonde qualification underway –Sippican – Intermet – Vaisala

12. Commercial Universal System NWS supported 10-station Caribbean network uses – NWS specified SPS – IMS 1500 tracker and computer software –Sippican B2 radiosondes India Installing IMS 1500 Universal System WMO GCOS IMS1600 Universal System in Tanzania –Integrates Sippican Mark II pressure radiosonde –Signal processing system NWS supported 10-station Caribbean network uses – NWS specified SPS – IMS 1500 tracker and computer software –Sippican B2 radiosondes India Installing IMS 1500 Universal System WMO GCOS IMS1600 Universal System in Tanzania –Integrates Sippican Mark II pressure radiosonde –Signal processing system

13. Universal System Issues Radiosonde providers may not wish to collaborate with Universal System providers –Small market vs large market –Proprietary SPS transfer equations, and software utilities utilities to make pressure adjustments and supply radiation corrections –Make radiosonde bandwidth and power output consistent with ground receiver bandwidth and antenna gain –Integration of Universal system needs to be fully tested before implementation Radiosonde providers may not wish to collaborate with Universal System providers –Small market vs large market –Proprietary SPS transfer equations, and software utilities utilities to make pressure adjustments and supply radiation corrections –Make radiosonde bandwidth and power output consistent with ground receiver bandwidth and antenna gain –Integration of Universal system needs to be fully tested before implementation

14. Conclusions Use of 1680 MHz RDF tracker for GPS radiosondes is feasible in areas where 403 MHz band is crowded Universal system viable with less expensive RDF radiosondes in areas such as the Tropics and Sub-tropics where limiting wind angles remain above 13-17 degrees Universal system enables radiosonde competiton Use of 1680 MHz RDF tracker for GPS radiosondes is feasible in areas where 403 MHz band is crowded Universal system viable with less expensive RDF radiosondes in areas such as the Tropics and Sub-tropics where limiting wind angles remain above 13-17 degrees Universal system enables radiosonde competiton