Wind Profiler Typical Performance Specifications |
Radar Frequency |
915 MHz or 1290 MHz |
Radar Wavelength |
0.33 meters |
RF Power |
50 W average, 600 W peak |
Antenna |
4.0 square meters, 26 dBi |
Beam Width |
9 degrees |
Minimum Height |
0.12 km AGL |
Maximum Height |
2 to 5 km AGL |
Height Resolution |
|
Low altitude mode: |
60 & 100 meters |
High altitude mode: |
250 & 500 meters |
Wind Speed |
~ 1 m/s |
Wind Direction |
~ 5 degree |
RASS Specifications |
Acoustic Frequency |
2000 Hz |
Acoustic Power: |
400.0 W |
Total Electrical Input |
|
Acoustic Beamwidth |
8.0 degrees |
Up to four sets of radar parameters can be defined for the ISS wind profiler and RASS system. These are set up interactively by the operator. The operator enters values for the inter-pulse period (IPP), the pulse width (PW), the number of heights (NHTS), the time from the first transmitted pulse to the first sampled height (DELAY), and the spacing between the sampled heights (SPACE). The four pulse widths available define the vertical resolution of the wind profiler and RASS. Those pulse widths are as follows:
- 400 nS pulse - 60 meter resolution;
- 700 nS pulse - 100 meter resolution;
- 1700 nS pulse - 250 meter resolution;
- 3300 nS pulse - 500 meter resolution.
The pulse width also defines the amount of energy transmitted by the radar and in most cases is reflected in the maximum altitude coverage. Another key factor in altitude coverage is the availability of scatterers to provide refractive index irregularities within the sample volume. Most variations in refractive index depend on the variation of temperature and humidity caused by turbulent eddies that are in a size range on the order of one-half the radar wavelength.
REFS:
Ecklund, W.L., D.A. Carter, B.B. Balsley, P.E. Currier, J.L. Green, B.L. Weber, and K.S. Gage, 1990: Field tests of a lower tropospheric wind profiler, Radio Sci., 25, 899-906.
Morse, C.S., R.K. Goodrick, and L.B. Cornman, 2002: The NIMA method for improved moment estimation from Doppler spectra, J. Atmos. Ocean. Technol., 19, 274-295.
Parsons, D., et al., 1994: The Integrated Sounding System: Description and preliminary observationsfrom TOGA COARE, Bull. Am. Meteorol. Soc., 75, 553-567.
Vaisala LAP3000 brochure (note: this instrument is no longer manufactured by Vaisala)