ER-2 Sortie 98-074
Friday, June 3, 1998
Steve Platnick: Flight Scientist
Objectives:Overfly the SHEBA ice camp (76°49N, 167°34W) in a star-shaped or "shamrock" pattern in coordination with University of Washington CV-580 aircraft for cloud remote sensing and cloud masking validation, cloud bidirectional reflectance measurements, and sea ice retrievals in the presence of changing cloud cover for AMPR. Overfly the ARM site on outgoing and incoming flight legs.
Takeoff 1900 UTC
Landing 0155 UTC (June 4)
The ER-2 overflew the ARM site on a NW flight line en route toward the SHEBA ice station. The ER-2 made four legs of about 260 km in length centered over the SHEBA ice station, with legs offset by 45°. A south-to-north leg was run first, repeating a pass from the previous days flight of 2 June 1998 (requested for assessing changes in AMPR sea ice retrievals with different cloud types and amounts). The CV-580 flew to SHEBA and attempted above and below-cloud bidirectional reflectance measurements and in situ profiles through the cloud. The ER-2 overflew the ARM site on the return to Ft. Wainwright.
The AirMISR was turned on for 6 acquisitions: once over the ARM site on the outgoing leg, four times over the SHEBA ice station, and once more over the ARM site on the return leg. The AirMISR operated at the following times with notes of observed clouds as seen by the instrument:
Pilot report: The ER-2 pilot reported solid midlevel cloud cover over the ice station on the initial flight tracks, with gradual clearing during the mission (some ice seen with the clearer regions to the northwest). On the outbound leg over the ARM site undercast to the west, thin cirrus over broken stratus. On return over ARM site clouds at all levels, some cirrus, some clearing.
Extensive stratus clouds with heights at about 3.5 km were expected over the SHEBA ice station. Morning report of fog with solid overcast clouds with flat and uniform tops at about 3.5 km associated with a strong inversion. Light cirrus between Barrow and the ice station. Surface winds out of the southwest at 5 kts. Morning satellite imagery showed a uniform stratus deck above the ice station. Later imagery from about the time of the ER-2 takeoff indicated that the upper stratus deck might be breaking up, some light cirrus seen in some locations.
At 2000 UTC, the ice station reported surface winds at 6 kts, 125° and a ceilometer cloud base of about 1 km. Radar showing two cloud layers: lower one at 1-1.2 km and a higher layer at 1.6-3 km. Near the time of the ER-2 arrival (2100 UTC), the lower cloud dissipated with the higher cloud layer thinning to 2-3 km, possibly liquid at the top. Low fog present at 2230 UTC.
AirMISR Airborne Multi-angle Imaging Spectroradiometer
AMPR Advanced Microwave Precipitation Radiometer
CLS Cloud Lidar System
HIS High-resolution Interferometer Sounder
MAS MODIS Airborne Simulator
MIR Millimeter-wave Imaging Radiometer
SSFR Solar Spectral Flux Radiometer