Objectives

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: Operation, maintenance, and improvement of the NOAA Profiler Network (NPN). Assessment of the Radio Acoustic Sounding System (RASS) for temperature profiling. Development of an operational surface-based integrated precipitable water (IPW) vapor monitoring system using the Global Positioning System (GPS), known as GPS-IPW. Development and deployment of the Alaska Profiler Network. Addition of wind and temperature data from Boundary Layer Profilers operated by other agencies. These combined observing technologies are shown in the map below of the Hourly Upper-Air Observing Network (current and future). Figure 32. Hourly Upper-Air Observing Network (current and future) including the NOAA Profiler Network, the Alaska Profiler Network, and other observing technologies. Accomplishments NOAA Profiler Network RASS Temperature Profilers NGPS Water Vapor Monitoring Alaska Profiler Network Boundary Layer Profilers Projections NOAA Profiler Network During Fiscal Year 1997, the Demonstration Division staff will continue to operate and maintain the NPN, improve the quality and quantity of data for operations and research, and constantly monitor the performance of the profiler network. The NPN power transmitters will continue to be rebuilt and operated at a slightly reduced output power level to extend their lifetime. Work will continue on improving the accuracy of the bird contamination check. Because of the increasing popularity of subhourly data with research meteorologists who are able to access them from archival storage, 6-minute, quality-controlled NPN winds will be distributed in real time to the research community. The division's various QC monitoring capabilities will be integrated into a single system, the QC Monitoring System (QCMS). The initial implementation of QCMS will include the basic QC monitoring products needed for NPN and BLP winds, and PSOS and GSOS surface data. Figure 40. Map of existing and planned boundary layer profiler stations. Radio Acoustic Sounding Systems Work will continue on investigating the impact of strong low-level winds on RASS height coverage. Upwind acoustic source placement in the range of 100 to 200 meters will be tested at Platteville, Colorado, this winter. Additional investigation may be conducted at one of the RASS sites in Oklahoma or Kansas next spring. 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 A lease will be secured for the Central site. All site construction will be completed, and power, telephone, and data communications lines will be installed. Antenna support steel will be shipped to Anchorage for delivery and installation at the three Alaska sites. Lockheed Martin will install three antennas on the government-furnished antenna support structure in Alaska and one antenna on the existing structure at Vandenberg Air Force Base. Power amplifiers will be delivered to Vandenberg AFB and Boulder for placement in the shelters and integration with other electronic components. Vendor training will be conducted on both the antenna and power amplifiers for NOAA and Air Force technicians at VAFB. Integration and testing of all interior electronic components for the Alaska system will be completed at the Boulder Assembly Facility. Shelters, with all electronics, will be shipped to Anchorage and then trucked to the three sites. Each shelter will then be connected to the antenna, system-wide testing will be performed, and then operations will begin. Spares for the 449 MHz frequency dependent components will be procured, and documentation of corresponding systems will be completed. The Boulder Profiler Hub will be modified for acceptance of the three new profiler sites. Data will be integrated into the Demonstration Division's standard output distribution. The Homer, Alaska, site will be removed and the components will be returned to the Demonstration Division 404 MHz spares stock. Experience with the Vandenberg AFB system and the three Alaska systems will help in performing an upgrade study to identify system capabilities that would be desirable for the future NWS-operated national profiler network. Boundary Layer Profilers Distribution of BLP data and products will be extended to NCDC, NCEP, Unidata (for the university community), and to the Web. Automated QC monitoring products will be made available to the providers of the BLP data to help them maintain their systems. Work will continue on acquiring data from additional BLP stations.