posted
Instrument:
Principal Investigator:
Co-Investigator:
Organization:
The Advanced Microwave Precipitation Radiometer (AMPR) is a total power scanning multifrequency radiometer which collects data at 10.7, 19.35, 37.1, and 85.5 GHz. The AMPR is composed of two adjacent antenna systems with one large scanning mirror accomodating both systems. One antenna system was designed to use a copy of the SSM/I feedhorn for the three higher frequencies. The second antenna system collects data at 10.7 GHz using a feedhorn designed by the Georgia Tech Research Institute (GTRI).
The AMPR is currently configured to fly aboard the high altitude ER-2 aircraft. The ground spatial resolution of the nadir footprints from the nominal aircraft altitude of 20 km is 0.6 km for the 85 GHz channel, 1.5 km for 37.1 GHz, and 2.8 km for both the 19.35 and 10.7 GHz channels. The AMPR calibrates with external cold and warm loads after every fourth data (surface) scan. A total calibration sequence or a total data scan are each performed in a three second time period. The AMPR scanner sweeps through a total 90 ° (+/- 45 ° from nadir) data scan collecting a sample for each channel every 1.8 ° for a total of 50 samples per channel. Based upon an aircraft altitude of 20 km and an aircraft speed of 200 m/s, this scan rate will yield contiguous footprints for the 85.5 GHz channel within a 40 km wide swath. The three other channels will be oversampled by the factors given in Table I. Also listed in Table I are other performance characteristics of the radiometer.
The feedhorns have been aligned such that full vertical polarization is 45 ° left of nadir and full horizontal polarization is 45 ° right of nadir. An equal mix of polarization occur at nadir. A more thorough discussion of the instrument may be found in Spencer, et al (1994).
Table I. AMPR Instrument Characteristics
IF 3dB Mainbeam Cross
Frequency Bandwidth Beamwidth Oversampling Efficiency Polarization
85.5 GHz 1400 MHz 1.8 ° 1.0x 93.2% 1.4%
37.1 GHz 900 MHz 4.2 ° 2.3x 98.8% 0.4%
19.35 GHz 240 MHz 8.0 ° 4.4x 98.7% 1.6%
10.7 GHz 100 MHz 8.0 ° 4.4x 97.8% 0.2%
The AMPR has flown in six major research programs and numerous instrument integrations between October, 1990 and October, 1995. A summary of these missions is given in Table II. The data for TOGA COARE, CAMEX-I and CAMEX-II missions are currently archived at the MSFC DAAC.
Table II. Summary of AMPR Flight Activity
Time Period Experiment Name Region of Interest
Aug - Sep Convection Atmosphere Moisture U.S. Atlantic
1995 Experiment - II (CAMEX-II) (Mass to Florida)
Sep - Oct Convection Atmosphere Moisture U.S. Atlantic
1994 Experiment - I (CAMEX-I) (Mass to Florida)
Jan - Feb Tropical Ocean Global Atmosphere SW Pacific Ocean
1993 Coupled Ocean-Atmosphere Response (Oceania)
Experiment (TOGA COARE)
Feb - Mar Storm-scale Operation and Research U.S. Midwest
1991 Meteorology-Fronts Experimental (lower and upper)
Systems Test (STORM-FEST)
Jul - Aug Convection and Precipitation/ Melbourne, FL area
1991 Electrification experiment (CaPE)
Oct, 1990 First AMPR flights, Jacksonville, FL Gulf of Mexico
Dr. Roy W. Spencer (NASA/GHCC Principal Investigator)
Ms. Robbie E. Hood (NASA/GHCC Co-investigator and Project Manager)
Mr. Frank J. LaFontaine (Hughes STX/GHCC Research Associate)
Mr. Ronald L. Schudalla (Hughes STX/GHCC Research Associate)
Spencer, R.W., Hood, R.E., LaFontaine, F.J., Smith, E.A., Platt, R., Galliano, J., Griffin, V.L., and E. Lobl, 1994: High Resolution Imaging of Rain Systems with the Advanced Microwave Precipitation Radiometer, Journal of Atmospheric and Oceanic Technology, Vol. 11, No. 4, pp.849-857.
Hood, R.E., Spencer, R.W., LaFontaine, F.J., and E.A. Smith, 1994: Simulation of Future Microwave Satellite Instruments Using High Resolution AMPR Aircraft Data, Preprints: Seventh Conference on Satellite Meteorology and Oceanography, Section 3.10, pp.160-163, American Meteorological Society, 6-10 June 1994, Monterrey, CA.
Smith, E.A., Xiang, X., Mugnai, A., Hood, R.E., and R.W. Spencer, 1994: Behavior of an Inversion-based Precipitation Retrieval Algorithm with High Resolution AMPR Measurements Including a Low Frequency 10.7 GHz Channel, Journal of Atmospheric and Oceanic Technology, Vol. 11, No. 4, pp.857.
Turk, J., Vivekanandan, J., Marzano, F.S., Hood, R.E., Spencer, R.W., and F.J. LaFontaine, 1994: Active and Passive Microwave Remote Sensing of Precipitating Storms During CaPE. Part I: Advanced Microwave Precipitation Radiometer and Polarimetric Radar Measurements and Models, Meteorology and Atmospheric Physics, Special Issue on Retrieval of Hydrological Variables from Space-based Microwave Instruments, Volume 54, pp.3-27.
J., Marzano, Mugnai, A., Smith, E.A., Xiang, X., Turk, J., and J. Vivekanandan, 1994: Active and Passive Microwave Remote Sensing of Precipitating Storms During CaPE. Part II: Intercomparison of Precipitation Retrievals Over Land from AMPR Radiometer and CP-2 Radar, Meteorology and Atmospheric Physics, Special Issue on Retrieval of Hydrological Variables from Space-based Microwave Instruments, Volume 54, pp.29-51.
Evans, K.F., Turk, J., Wong, T., and G.L. Stephens, 1995: A Bayesein Approach to Microwave Precipitation Profile Retrieval, Journal of Applied Meteorology, Volume 34, Number 1, pp.260-279.
Back to the TEFLUN Instrument Description Page
Back to the TEFLUN Overview Page
Back to the TEFLUN Mission Home Page
Back to the ESPO Missions Home Page
Back to the ARC Earth Science Division Home Page
Back to the NASA/ARC Home Page