Instrument Names:         DC-8 Microwave Temperature Profiler (MTP/DC8)
                                         ER-2 Microwave Temperature Profiler (MTP/ER2)
                                         WB-57F Microwave Temperature Profiler (MTP/WB57)

Principal Investigator:   Dr. Michael J. ("MJ") Mahoney, JPL/Caltech

Recent Missions: On the DC-8, the MTP has flown on CAMEX-4, SOLVE, PEM Tropics B, SONEX, SUCCESS, and TOTE/VOTE. On the ER-2, it has flown on CAMEX-4, SOLVE, CIREX, STRAT and POLARIS. On the WB-57F, the MTP has flown on ACCENT, ACCENT II and WAM. Also, in 2000, the MTP flew on the NCAR L-188C in the Texas Air Quality Study. Since the late 1980s, MTPs have an enviable performance record of nearly 500 successful flights and more than 3100 flight hours.

Overview: The MTP retrieves profiles of air temperature versus altitude along an aircraft flight track. It does this by measuring the natural thermal microwave emission from oxygen molecules in the earth’s atmosphere, and then performing a statistical retrieval inversion procedure, based on an archive of thousands of radiosondes, to obtain the most likely temperature profile given the measurements. On the DC-8 this retrieved profile displays on monitors throughout the aircraft, and can be used for real time flight planning. On the ER-2 the MTP operates autonomously, and the data is processed after recovery.

Objectives: During CRYSTAL-FACE, MTPs will make measurements of the temperature field about the WB-57 and ER-2 flight tracks. Temperature is a primary state variable of the atmosphere, and its measurement is essential to place in situ and remote measurements of chemical species and aerosols in proper meteorological context. MTP data will also be used to verify numerical weather models, especially on mesoscales, where satellite measurements are inadequate. MTP measurements will also be used to validate satellite data.

Experiment Operations: The JPL WB-57 Microwave Temperature Profiler, a passive microwave radiometer, will measure 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. The real-time display presented in the backseat of the WB-57 consists of air temperature versus altitude, from near the surface to 24 km, which is updated every 14 seconds. The ER-2 MTP operation is similar, but a realtime backseat display is not available. Both MTPs weighs only 10 kg (22 lbs) and are contained in two small packages about the size of a shoebox. The WB-57 has an additional 10 lb box that produces the realtime backseat display.

Benefits: MTP temperature measurements will help scientists understand the effect of diabatic heating and cooling, which is associated with water phase changes, on hurricane dynamics. Together with moisture and wind, temperature is one of the primary state variables needed to initialize numerical weather prediction models, and hence to understand the model's ability to track hurricanes and predict their intensity at landfall. MTPs will also be able to contribute to the validation of satellite temperature measurements, especially in non-clear sky conditions. Finally, the MTP data will be used to carry out independent research such as studying the role of convectively-generated gravity waves in atmospheric dynamics.

MTP Home Page: http://mtp.jpl.nasa.gov

WB57 MTP Description: http://mtp.jpl.nasa.gov/missions/crystal/MTP_WB57.html

ER2 MTP Description: http://mtp.jpl.nasa.gov/missions/crystal/MTP_ER2.html