CASES-97 has firm committments from the NSF Deployment Fund for use of the Univ. Wyoming King Air Facility and from NOAA Aircraft Operations Center for the use of the recently instrumented NOAA Twin Otter. This is a perfect pair of aircraft to work the watershed as they are relatively small allowing for tighter turns and less public disturbance during low-level missions (most of them). Bob Grossman (Univ. of Colorado) is the PI for the Wyoming King Air and Bob McMillen (NOAA Air Resources Laboratory) is th e PI for the NOAA Twin Otter. Both aircraft will have the capability of measuring turbulent fluxes of heat, moisture, and momentum as well as a full suite of global radiation devices (up and down looking). Additionally the NOAA Twin Otter will be able to measure CO2 and O3 fluxes. This deployment is very efficient as the aircraft base will be close to the watershed so the relatively short duration (compared to NOAA's P3 and NCAR's C-130/Electra) is not a big problem; this was one reason why the Walnut River Watershed was chosen. Anyone interested in putting fast response CO2 and O3 instruments on the Wyoming King Air should contact Grossman before 20 February.
As part of the general CASES-97 Planning Meeting, an aircraft users meeting was held in middle November. At that meeting PIs, pilots, project managers, and technicians got down to business. Here are the main players:
If you have any questions about aircraft operations, instruments, or adding instruments (as a piggy back), contact the PIs first.
The Aircraft Coordination Meeting went very smoothly, even ended on time despite the fact that it was chaired by Grossman. A complete summary can be found here.
The objectives of CASES-97 as they relate to aircraft operations were introduced by Grossman and McMillen, followed by a general discussion of those scientific issues. The aircaft will be mainly used for budgets, mapping, and checking out the profiler winds and virtual temperatures (from the RASS).
Instrument systems for each aircraft were presented. It was noted that both aircraft have recent instrumentation for turbulence measurements. The King Air has flown intercomparison missions with the NCAR Electra and NAE(Canada) Twin Otter during BOREAS; t his data is presently being worked up by BOREAS Scientists. They have agreed to share their preliminary results with Grossman and Lemone so they can assess the instrumentation in light of the scientific objectives. Gordon expressed the opinion that it app eared the comparison of turbulence quantities was good. The NOAA Twin Otter has only a few missions under its belt so intercomparison missions are lacking; however, the Air Resources Laboratory, closely associated with the Twin Otter instrumentation, has had extensive experience in turbulence measurments from towers and aircraft. NOAA will conduct a seperate assessment of the Twin Otter instrumentation before deployment to the field.
Piggy-back instruments, up to the limit set by the Facilities, are encouraged. To date a slow (10s response time) ozone instrument has been proposed (J. Snider, U.Wyoming) for the King Air. NCAR (G.Kok, RAF) has supplied a fast (.05 s response time) ozone instrument for the Twin Otter.
The meeting devoted a considerable time to the discussion of the aircraft operations base. Minimum requirements were presented. Several candidates were presented for assessment by the Facilities managers/pilots. Since that time, the Facilities have agreed to use Ponca City, Oklahoma. A good base closer to the watershed was found at Jabara Airport northeast of Wichita; this base wa s rejected by the pilots because it did not meet minimum safety requirements (no ILS). This choice will mean that the operations base for surface-based instruments (profilers, PAMs, ASTER, hydrology) will be separated from the aircraft operations base in Ponca City. Other expeditions have met this challenge sucessfully and the PIs are famil iar with those situations. A multiplexed speaker phone and access to the internet (for forecast and CASES-97 operations materials) will be a necessity for coordination of surface and aircraft operations. The Aircraft Operations Center will be in the Pump R oom of the Marland Manor Hotel, Ponca City. An important part of the daily briefing will be the status of the instruments and platforms. It was agreed that the Project Managers will be the primary contact for this information which should be available to the surface operations center several hours before the daily briefing; this may be difficult if the aircraft are on a mission at that time.
Grossman went over the various flight mission modules and related them to the scientific objectives. These modules were for single and dual aircraft missions. Grossman explained that dual aircraft missions could be used in two ways: to extend space (over a short time interval, necessary for budgets), and to extend in time (doubling the time spent over a given area for diurnal variations studies). Most missions in CASES-97 will be dual missions.
In light of the scientific objectives and logistics, flight safety was also thoroughly discussed. The Facilities will publish their crew rest limitations as part of the CASES-97 Operations Plan. Most of the discussion centered on the low-level flight legs that will form a major part of the aircraft data. In order to fly lower than 500 feet above the highest local object, a waiver must be obtained from the Federal Aviation Administration. Such a waiver will allow pilots to go as low as they safely determine . Presently for NOAA that is 200 feet and for NSF, 100 feet. The NSF and NOAA Facilities will seperately apply for the low-level waivers for their pilots. Additionally, Grossman requested Wellman and Nokutis to explore a relaxation of the "internal" NOAA restriction of 200 feet to 100 feet so that it is compatible with the King Air missions to estimate surface fluxes. Since that time Grossman has worked with a local area pilot and determined 7 low-level flight lines from the southeast to northeast portion s of the watershed which meet the FAA requirements for a low-level waiver. These lines have been passed to the Facilities which are currently filing waiver requests from the FAA. Grossman and LeMone will supply any scientific justification that the FAA ma y require.
Flight mission planning was also dicussed and a tentative time line was introduced. A daily conference call to the surface operations base will be necessary and planners will have to insure that capability. Intercomparison legs are planned as part of all coordinated aircraft missions. This leg is likely to be the ferry leg from Ponca City to the southern boundary of the watershed at Winfield, Kansas; it will be flown at the lowest safe altitude (no FAA waiver for this leg). The intercomparison leg will al so be considered a science leg.
The presentation of post-flight debriefing and quick-look processing needs resulted in a debriefing schedule. The discussion regarding quick-look processing showed the need for the PIs to interact with the Facilities engineers and data managers to insure that they also have enough data for a scientific assessment. The engi neering assessment of data quality is shared between the PIs and Facility engineers. The Facilities were advised of the possibility that a Quick-look Data meeting may be held in November 1997 for a first order assessment of the expedition. Data formats we re also discussed. The PIs requested that a single format be used for both aircraft to avoid trouble in post-field processing.
The discussion of post-field data processing emphasized the need for a common data format, common processing packages (so computations will only depend on the source of the data), and fair data release schedule. All CASES-97 data will be available to the public. Three data sets emerged:
The Facilities were encouraged to take a scientific interest in CASES-97.
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