200 likes | 366 Views
2 (14) Universal Upper Air Sounding System. World Meteorological Organization WMO Technical Conference on Meteorological and Evironmental Instruments and Methods of Observation – TECO 2005. What is a Universal Upper Air System?. Flies sondes from any qualified manufacturer
E N D
2 (14) Universal Upper Air Sounding System World Meteorological OrganizationWMO Technical Conference on Meteorological and Evironmental Instruments and Methods of Observation – TECO 2005
What is a Universal Upper Air System? • Flies sondes from any qualified manufacturer • Operates in multiple modes (RDF/GPS) • Complies with WMO and national reporting requirements Photo courtesy of NOAA Archive
Universal System 1930s Optical Theodolite Photo courtesy of NOAA Archive
Universal System 1940s SCR-658 Manual Radiotheodolite Photo courtesy of NOAA Archive
Universal System: 1950s ART-1 and ART-2 Automatic Radiotheodolites Photos courtesy of NOAA Archive
1990: GPS Revolution • Rapidly dominates synoptic market by offering high accuracy and ease of use • High cost of disposables becomes unsustainable for many operators - leading to darkened sites Image courtesy of USAF Research Lab
In 2000 the Radiotheodolite returns as part of the NWS Radiosonde Replacement System Photo: InterMet Systems
TRS: Telemetry Receiving System • Multi-Sonde Compatible • Dual-Mode (GPS / RDF) • Digital Architecture • All Environment • High Gain / Long Range • Easy to Operate Photo: InterMet Systems
2002: iMet-1500 • TRS technology in a flexible format • Digital receiver with tunable bandwidth • Multi-sonde compatible • Multi-mode GPS/RDF • Military or Synoptic Photo: InterMet Systems
2004: iMet-1700 • TRS technology at a lower cost • Fixed site installations • Fewer moving parts, reduced maintenance • Multi-sonde compatible • Multi-mode GPS/RDF Photo: InterMet Systems
GPS Maintenance free Accurate winds in all conditions Release and forget operations RDF Complex hardware Inaccurate winds at low elevation angles Training and experience required Operational factors favor 403 MHz GPS: • When properly integrated, PTU is a function of the radiosonde, and should be independent of the wind finding methodology
Tanzania Evaluation • In October 2004, a team lead by Dr. John Nash from the Met Office evaluated an iMet-1500 installation on behalf of the WMO. • More training was required for a staff that had not conducted synoptic flights for 10 years • Identified important integration issues • RDF Wind accuracy was deemed acceptable for operational use in the Tropics
Low cost disposable Multiple vendors for sonde reorders Cost factors favor Universal RDF: Estimated Savings from Universal RDF System:
The Signal Processor (decoder) is the key to multi-sonde use Other Issues: Bandwidth Frequency selection Transfer of calibration coefficients Solar correction Signal Processor Universal Compatibility:
Meteorological Issues: • Are RDF winds accurate enough for tropical locations with a low incidence of low angle tracking? • Is a competitive market for annual sonde reorders compatible with providing consistent PTU time series data?
Conclusions: • There is a place for Universal RDF Systems in the GUAN • Additional work needs to be done on data quality and the potential impact of annual sonde changes Photo courtesy of NOAA Archive