The Demonstration Division evaluates promising new atmospheric observing technologies developed by the Environmental Research Laboratories and other organizations and determines their value in the operational domain. Activities range from demonstrations of scientific and engineering innovations to the management of new systems and technologies. Currently the division is engaged in five major projects:
Figure 32. Hourly Upper-Air Observing Network (current and future) including the NOAA Profiler Network, the Alaska Profiler Network, and other observing technologies.
AccomplishmentsNOAA Profiler Network
RASS Temperature Profilers
NGPS Water Vapor Monitoring
Alaska Profiler Network
Boundary Layer Profilers
ProjectionsNOAA Profiler Network
Figure 40. Map of existing and planned boundary layer profiler stations.
Radio Acoustic Sounding Systems
GPS Water Vapor Monitoring
In 1997, plans for the GPS water vapor monitoring include demonstrating the ability to acquire and process GPS-IPW data from a network of sites (consisting of NOAA and other-agency GPS receivers) in real time; providing these data to modelers and forecasters every 30 to 60 minutes with no more than a 15-minute delay; and assisting in demonstrating that GPS-IPW data have a significant positive effect on mesoscale forecast accuracy. To accomplish these goals, it will be necessary to have both long baseline geodetic control and highly accurate satellite orbits in real time; currently, these data are available with about a day delay.
The locations of four "Long Baseline Sites" to be established through the cooperation of ERL management in 1997 are shown in Figure 41. These sites (identified in the Table) will furnish the geodetic control that is traditionally provided by widely spaced International GPS Service for Geodynamics (IGS) tracking stations, but will do so in real time. These sites will enable the formation of the baselines necessary to calculate precipitable water vapor in real time using the "absolute" technique first demonstrated in 1995 by the Scripps Institution of Oceanography and the University of Hawaii.
Figure 41. Locations of "Long Baseline Sites."
Click here to see a table of long baseline sites and approximate baseline sites.
Most of the civilian orbit facilities (currently seven) generate improved satellite orbits for the previous day in less than 24 hours. What is required for real-time precipitable water vapor calculations, however, is for orbits of sufficient accuracy to be available at all times during the current day. Right now, the most promising way to accomplish this appears to be by predicting the orbits of the GPS satellites at least one day in advance. Some orbit facilities, including SIO, Jet Propulsion Laboratory, and Bern, Switzerland, are already producing predicted orbits on an experimental basis. Plans call for an assessment of the impact of these predictions on precipitable water vapor, similar to an evaluation performed in 1995 on the impact of rapid orbits on precipitable water vapor accuracy.
During 1997 GPS-IPW systems will be installed at two additional NPN sites in the Central U.S.: Granada, Colorado, and DeQueen, Arkansas. Also, sometime next spring, GPS and GSOS systems will be installed at the three new Alaska sites, in Central, Glennallen, and Talkeetna.
As previously mentioned, a very cost-effective way of expanding the number of GPS-IPW sites is to utilize the GPS data acquired by other federal agencies such as the U.S. Coast Guard (USCG). An amendment to an existing Memorandum of Agreement between NOAA/National Geodetic Survey (NGS) and the USCG will provide the go-ahead for the Demonstration Division staff to install GSOS at USCG and U.S. Army Corps of Engineers DGPS sites, and to transmit the surface meteorological data acquired by these units to NGS along with the GPS data already acquired there. In cooperation with USCG, Demonstration Division staff will install 10 DGPS units at the sites identified in Figure 32 during 1997. These DGPS sites were selected by FSL's Forecast Research Division, because they are expected to provide the most definitive information needed to assess the effect of GPS data on mesoscale forecast accuracy. It is hoped that these activities will lead to demonstrated improvements in operational moisture, cloud, and precipitation forecasts in MAPS/RUC. In addition, demonstration is anticipated of the ability to predict GPS tropospheric delays using the information provided by GPS-IPW observations and surface meteorological data. This capability is expected to have a significant impact on GPS surveying and positioning accuracy.
Alaska Profiler Network
Boundary Layer Profilers
This page designed/maintained by: Wilfred von Dauster Last modified 5 August 1997