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The ER-2 flew five, figure eight, overpasses of the CART site, with the last leg extended to overfly a convective cloud deck. The DC8 flew also.
ER-2 Flight: 96102
Date: April 13, 1996
Mission: Radiation Measurement Mission Over ARM Site
Mission Objectives
Atmospheric radiation measurements over the ARM CART site. Comparison of ER-2 downlooking with surface based uplooking instruments.
Flight Summary
Take off was 1740 UTC and return time was 2020 UTC. ER-2 flew a figure eight pattern 2 1/2 times over ARM CART site (36 36.6'N 97 34.8'W) . Horizontal legs were approximately 70 nautical miles long. North bound leg was 295 degrees (true north), south bound 135 degreess. Final northbound leg was extended approximately 120 nautical miles past the ARM site to overpass developing convection.
Around 1800 UTC convective cells west of Witchita were seen on radar.
Highlights
Clear sky conditions useful for ARM science objectives. Overflight of convective cloud deck on return leg. Five passes over the ARM site (approximately1830, 1843; 1857; 1910 and 1923 UTC)).
Instrument Status
Additional Pilot Notes:. Cloud free conditions over the ARM CART site.
DC-8 SUCCESS flight #202 (scientist: Brian Toon)
SUMMARY: The basic flight went very well. All of the instruments are functioning, with some small problems left to be worked out. We met all of our major objectives, testing instruments, calibrating the MMS and transiting to Kansas. We also met most of our secondary objectives. We were able to sample our own contrail and cirrus for a significant period of time. However, the rendezvous with the T-38 did not work out due to logistical problems, and contrails were not present at the time it was attempted. Several preliminary science observations were made that are interesting, including size of ice crystals in cirrus and contrails, IWC of contrails, and possible compositional clues about ice nuclei.
DC-8 TEST-FLIGHT
Secondary goals are:
OPERATIONS
FLIGHT PLAN:
Planned takeoff: 17.00 GMT (10.00 local time)
PART 1: Off California Coast. The plan here is to repeat the general pattern of the previous flight of 4/10/96 in a restricted space over the water. We will first do low altitude (5kft) boxes to calibrate the MMS. We will then ascend to about 20kft and again perform box manuevers. Finally, we will ascend to just below the tropopause and again perform box manuevers. The trop height will be identified from MMS in advance of the final altitude change. We will perform several 30o banking turns at max. altitude in an attempt to encounter our own exhaust/contrail. The lidar will be operated in a forward scanning mode during all of this period. Turns should be made to the right so that the lidar can see the contrail ahead of the aircraft. This portion of the flight will require about 2 hours.
PART 2: Transit across California and Nevada. There is some chance of encountering cirrus on this leg. Therefore we would like to stay just below the trop as measured by MMS, or descend if needed into cirrus. Laser in vertical mode.
PART 3: Transit across eastern Nevada and Utah. We expect no cirrus in this region. We would therefore like to cross into the stratosphere once we cross the jet. We will have to identify the location of the jet crossing in real time therefore, we will request max altitude possible on this leg. Laser off when we enter Denver airspace.
PART 4: Once we enter New Mexico it will again be possible to find cirrus. We would like to descend below the trop (from MMS) and locate an altitude where the DC-8 is making a good contrail.
PART 5: We will rendezvous with the T-38 over New Mexico and Kansas. Our emphasis is on in-situ observations of the exhaust rather than lidar. We will try to sample the exhaust or contrail of the T-38. It is not possible to fire the laser in a forward mode so we will use it in a vertical mode. If we cannot see the exhaust visually, we will use Weinheimer's instrument to try to identify when we are in the exhaust. We would like to stay in the exhaust for 3-4 min, then stay out of it for an equal period of time.
PART 6 Land in Kansas.
TAKEOFF/LANDING
The DC-8 left Ames at 17.15 UTC (10.15 am local time) and arrived at Salina at 22.30 UTC
FLIGHT REPORT
Take off was 17.14:34 GMT. Power up procedures are starting too late, and MMS still has problems maintaining the INS calibration during the power up sequence.
PART 1: The calibration manuevers for the MMS were successful at all altitudes. However, the pilots were not able to perform the Yaw manuevers at the highest altitude. At least 3 people were airsick from these manuevers. We also encountered cirrus over the ocean so we were able to test the ice instruments. The cirrus seemed to have relatively small particle sizes, so much of it may have been from old contrails. The pilots were able to do a thirty degree banking turn and stay within the contrail for much of each turn. The aircraft and the contrails cast a circular shadow on the ocean surface. Visually it was difficult to see the contrails ahead of the aircraft against the background of the pre-exisiting cirrus. However, it was clearly visible blowing over the cockpit of the DC-8.
PART 2: cirrus were present along this part of the flight. We crossed into the stratosphere near the Utah border. The DC-8 continued to lay a contrail even though we were a thousand feet above the trop.
PART 3: We were in the stratosphere here as desired.
PART 4: No cirrus were present along this leg, and the DC-8 did not lay a contrail. Even at 35kft the in situ sensors suggest that we are still in the stratosphere.
PART 5: We do not expect to see the T-38 contrail. Therefore, we are using the Weinheimer instruments and CN counters to look for the exhaust trail. The T-38 was easily visible from the DC-8 as it moved in front of us. However, given the airspeed difference, short flight time of the T-38, and problems in setting up the rendezvous not enough time was available to complete this exhaust manuever.
METEOROLOGY-REPORT
FORECAST: There are several rapidly moving systems crossing the US that may be encountered. In the region just off the California coast there may be cirrus near the tropopause, however cirrus is expected to build during the day, so we might be too early for it. Cirrus is also expected over Western Nevada. We should pass into the stratosphere over Eastern Navada and Utah as we cross a jet stream. No cirrus are expected in this region. Cirrus or contrails may also be present between New Mexico and Kansas. However, the cirrus are moving away as the day progresses so we might miss them.
OBSERVATIONS: There were cirrus and contrails present throughout the altitude range 25-39kft over the Pacific ocean. Numereous persistent contrails were present so it was often difficult to distinguish visually the contrails from cirrus. At 35kft where we did the final manuever for the MMS we had cirrus At take off broken fair weather cumulus were present with scattered cirrus over Ames. Local cirrus were not predicted earlier. Cirrus were not present over Oregon, or Northern California. The trop was also significantly lower than expected, so part of the flight to the north was in the stratosphere. We requested a descent into a low cloud deck, probably around 20kft on the south bound leg toward the restricted area.
INSTRUMENT STATUS
All of the instruments on the DC-8 are functional for this flight. The wing tip instruments are a replicator (Hallet), VIPS, MASP and 1-DC. When in cirrus the CVI would like altitude changes at 1000 ft/min or less.
Weather Conditions from Site Operators Log
Extensive cirrus and cirrostratus from 15:00 to 20:00. Some broken altocumulus later in the afternoon.
Key: O = operational, X = down or degraded
There are four staffed Boundary Facilities, each having Balloon Borne Sounding Systems (BBSS) and MicroWave Radiometers (MWR). During the IOP period, sondes are launched every three hours round the clock, starting at 5:30 GMT (12:30 CST). The sites are listed below. Times listed following a site indicate questionable data or failed sonde launches. Weather conditions are recorded in the Boundary Facilities Site Operator's Log.
There are numerous unstaffed Extended Facilities. The specific instrumentation at the extended facilities varies from site to site, but generally includes a flux station (either an Energy Balance Bowen Ration (EBBR) system or an Eddy Correlation (ECOR) system), a Solar and InfraRed Observing System (SIROS), and a Standard Meteorology Observing Station (SMOS). For the locations of the Extended Facilities, and their suite of instrumentation, see the table and map of the Extended CART site. The comments below indicate specific data streams with identified problems.
A good flight day for the ER-2 with several figure-8 overpasses above the CART.