MODIS Airborne Simulator (MAS)

Objective and Summary:

• Fly the ER-2 repeatedly over the surface site at Barrow (71°19.37'N, 156°34.9'W), coordinated with the University of Washington CV-580, followed by a flight to the SHEBA ice station (76°20.31'N, 166°37.45'W) and finally to a flight track parallel to the NOAA-14 ground track.
• The mission was coordinated with the CV-580, with the ER-2 flying flight legs between single level Arctic stratus clouds over the tundra South of Barrow, to broken clouds over the ARM site, to clear sky over the ice. The entire flight track over the Chukchi and Beaufort Seas was cloud free.

Coordinations:

• University of Washington CV-580 aircraft (between 2009 and 2202 UTC)
• F-14 satellite (2121 and 2301 UTC)
• NOAA-14 satellite (2326 UTC)
• Solar noon (2301 UTC)

Key Flight Legs:

• The ER-2 flew a NNE flight line from point 1 (70°17'N, 158°W) to point 2 (72°40'N, 155°W), overflying the ARM site each time, that consisted of 5 flight legs 285km in length.
• Following this coordinated pattern with the CV-580, the ER-2 flew a NW flight track to point 4 (74°N, 166°37.45'W), where it turned and headed North to point 6 (77°N, 166°37.45'W), consisting of a single flight leg 333km in length. This flight track passed over the SHEBA ice station at 2303 UTC.
• Finally, the ER-2 headed SSE on a heading of 143.76°, aligned with the NOAA-14 overpass at 2326 UTC.
• The AirMISR was turned on for 6 acquisitions: four over the Barrow ARM site, one over the SHEBA ice station, and one at the time of the NOAA-14 overpass. The AirMISR operated at the following times with notes of observed clouds as seen by the instrument:
  • 2011-2025 UTC (ARM)
  • 2043.75-2058 UTC (ARM)
  • 2112.75-2125 UTC (ARM)
  • 2145.75-2200 UTC (ARM)
  • 2256-2308 UTC (SHEBA)
  • 2320-2328 UTC (NOAA-14)

Pilot Report:

• The ER-2 pilot reported undercast conditions over all of Alaska enroute to and from Barrow, with thick Arctic stratus clouds on the South side of Barrow, with clear sky over the ice.

Meteorology:

• A single layer cloud system occurred near and to the South of Barrow, with severe clear over the Beaufort Sea. A high pressure system was located just NE of the SHEBA ice station, with low stratus to the NE. This cloud was moving toward the West, but did not move over the SHEBA ice camp at any time during the mission.

Instrument Status:

• AirMISR (Airborne Multi-angle Imaging Spectroradiometer): The first two scenes collected 5 of 9 look angles (nadir and the last 3 aft view angles not recorded); subsequent acquisitions obtained all 9 look angles until the SHEBA acquisition when the data collection was truncated; final data collection sequence during the NOAA-14 overpass was not acquired
• AMPR (Advanced Microwave Precipitation Radiometer): Worked well
• CLS (Cloud Lidar System): Worked well
• HIS (High-resolution Interferometer Sounder): Worked from take-off to near SHEBA the first overpass (~1.5 hr) and then failed; cause not determined
• MAS (MODIS Airborne Simulator): Port 4 (8.3-14.0 µm) disconnected for nitrogen purge
• MIR (Millimeter-wave Imaging Radiometer): Worked well
• SSFR (Solar Spectral Flux Radiometer): Worked well