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) and nearby open water and fast ice of the Chukchi and Beaufort Seas.
• The ER-2 flew three parallel and repeating ground tracks of 261km in length that were parallel to the NOAA-14 ground track at 2304 UTC (heading of 347.13° at SHEBA). Due to malfunction of the backup navigation equipment onboard the aircraft, the mission design that included parallel ground tracks over SHEBA was modified to fly a similar pattern over ARM.
• The entire flight track over the Chukchi and Beaufort Seas was cloud free, with Arctic stratus present over land and nearby coastal fast ice.
• All times, orbital inclinations, and timings were based on overflights of SHEBA (76°20.76' N), rather than Barrow, so some of the angles are off of the intended times and orbits planned for this mission.

Coordinations:

• F-14 satellite (2237 UTC)
• NOAA-14 satellite (2304 UTC)
• Principal plane of the Sun (2218 UTC)

Key Flight Legs:

• The ER-2 flew a NNW flight line from point 1 (70°09'N, 155°31'W) to point 2 (72°26'N, 157°14'W), then reversed course, overflying the ARM site each time (two passes). The aircraft then flew a parallel track displaced 40km to the West with two round trip flight legs, followed by another pair of flight legs displaced 40km to the East. Each flight leg was 261km in length. The flight tracks were all parallel and on a heading of 347.1°/167.1°, corresponding to the orbital inclination of NOAA-14 as it overflew the SHEBA ice station at 2304 UTC.
• The AirMISR was turned on for 5 acquisitions: over the Barrow ARM site and nearby tundra, including acquisitions when the sun was in the orbital inclination of NOAA-14 (at least at SHEBA), and when the NOAA-14 and F-14 satellites passed over the area. The AirMISR operated at the following times with notes of observed clouds as seen by the instrument:
  • 2112.5-2128.5 UTC (ARM)
  • 2139.5-2154.5 UTC (ARM; sun in principal plane at ARM)
  • 2208.5-2225.5 UTC (West; sun in principal plane at SHEBA)
  • 2234.25-2250 UTC (West; F-14)
  • 2302.5-2317.5 UTC (East; NOAA-14)
  • 2330.75-2345.75 UTC (East)

Pilot Report:

• The ER-2 pilot reported Arctic stratus conditions over the tundra until 55km North of Barrow, with clear sky and possible haze or thin cirrus over the ice.

Meteorology:

• A single-layer stratus cloud system covered Barrow, extending about 100km North over the ice. Cloud top temperatures were nearly uniform, surface winds were Easterly around 20kts.

Instrument Status:

• AirMISR (Airborne Multi-angle Imaging Spectroradiometer): The 2^nd, 3^rd, and 4^th runs collected all 9 look angles, while the remaining 3 scenes collected a minimum of nadir and the first 4 view angles.
• AMPR (Advanced Microwave Precipitation Radiometer): Worked well
• CLS (Cloud Lidar System): Worked well
• HIS (High-resolution Interferometer Sounder): Worked well
• 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