| Instrument: | DC8 Microwave Temperature Profiler (MTP/DC8) |
| Principal Investigator: | Michael J. ("MJ") Mahoney |
| Organization: | Mail Stop 246-101 Jet Propulsion Laboratory National Aeronautics and Space Administration 4800 Oak Grove Drive Pasadena, CA 91109-8099 |
Measurement Description: The JPL DC8 Microwave Temperature Profiler (MTP/DC8) is a passive microwave radiometer that measures the natural thermal emission from oxygen molecules at three frequencies (55.51, 56.66 and 58.79 GHz). The instrument views ten elevation angles between - 80 and +80 degrees by using a scanning mirror -- located behind a microwave window on the sensor unit -- to change the viewing direction. As shown in the figure above, the sensor unit is located in a window just aft of the forward starboard exit door. This window has always been considered inaccessible for science instruments or inlets because it is immediately behind the Mission Manager's console. The sensor fairing is far enough ahead of other usable windows that it should not interfere with any future sampler inlets. The control and analysis electronics for the MTP are located in the Mission Manager's rack. The MTP retrieves profiles of air temperature versus altitude, which it displays on a dedicated color LCD display beside the Mission Manager's console; a video signal is also available for distribution to DADS monitors throughout the aircraft.
Default MTP Realtime Display: The real-time display consists of air temperature versus altitude, from near the surface to 24 km, which is updated every 17 seconds. For a nominal flight altitude of 10 km, simulations and comparisons with radiosondes show that RMS performance is better than available from synoptic-scale analyses (such as NMC); the RMS accuracy for 1 minute (the average of 4 scans of data) is 0.5 K at the flight altitude, <1.5 K from 7-14 km, and <2 K from 6 to 15 km). The realtime display includes a prominent indication of tropopause altitude, both graphically and in a text information box overlay. When a second tropopause is present, as occurs near jet streams and stratospheric instrusions, it also is indicated graphically and included in the table.
Data Products Produced by MTP Experimenter: A MTP experimenter on board the DC8 can control the video display of real-time data via a local area network that runs from the experimenter's computers to the real time computer. Although thorough post-flight analysis is needed to verify instrument calibration and data integrity, many data products that traditionally have only been available after a mission are now available in real time. These products include