Summary of the Data Flights

During the period of the Cessna's TOGA COARE flights, the aircraft and its associated personnel of scientists and technicians were based in the town of Rabaul, on the island of New Britain, Papua New Guinea. This location was chosen because it was the nearest settlement to the centre of the TOGA COARE domain capable of supporting such an operation. Despite this, it was still necessary for the aircraft to spend much of its time in ferry flight to and from the main experiment site, the Intensive Flux Array (IFA), some 400km away.

A total of 18 data-gathering missions were flown during the Intensive Observation Period (IOP). Brief summaries of these appear in the table below. As well as a large number of data-gathering missions in the IFA, several intercomparisons were performed between EOS and the oceanographic vessels "Franklin" and "Malaita", and the NCAR Electra aircraft. Two extensive deep sounding patterns were also performed in the vicinity of the Kavieng ARM/PROBE site. Roughly half the IFA missions were horizontal patterns mapping the lower boundary layer, and the remainder were vertical "stack" patterns.

The long ferry flights to IFA, and the additional requirement that the aircraft should fly low whilst ferrying in order to optimize fuel consumption, presented the opportunity to further augment the already potentially large data set by fast (20Hz) sampling during ferry time. This was done on several of the later IFA missions. The EOS missions during TOGA COARE have thus resulted in an exceptionally comprehensive and extensive data set (total size of raw data files around GigaByte), which promises to make an outstand- ing contribution to the enormous body of information produced as a result of the TOGA COARE experiment.

3.1 Failures

Preliminary analyses, and first comparisons with data from the "Franklin", have revealed a very high quality data set, with few problems. The major known failings are listed below. Other minor problems are specified in Chapter 4.

The up-welling (downward-facing) long-wave radiometer aboard EOS did not work correctly throughout the TOGA COARE IOP. Surface temperatures from the Heimann KT-15 sensor have been converted to long-wave radiation values to replace this sensor in the computation of net radiation. Tests indicated that this seems to be working well.

The Lyman-Alpha Hygrometer malfunctioned during the last few flights. Luckily, the fast open-path CO2/H2O gas analyser, on loan for test purposes from NOAA/ATD, appears to have been functioning correctly during that period.

The nose-cone channel giving angle of attack ("alpha") occasionally exhibits a high frequency oscillation which is probably caused by rain penetration. This may damage fluxes on the affected runs, although it is unlikely to be correlated with vertical velocity.

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	The up-welling (downward-facing) long-wave radiometer aboard EOS did not work correctly throughout the TOGA COARE IOP. Surface temperatures from the Heimann KT-15 sensor have been converted to long-wave radiation values to replace this sensor in the computation of net radiation. Tests indicated that this seems to be working well.
	The Lyman-Alpha Hygrometer malfunctioned during the last few flights. Luckily, the fast open-path CO2/H2O gas analyser, on loan for test purposes from NOAA/ATD, appears to have been functioning correctly during that period.
	The nose-cone channel giving angle of attack ("alpha") occasionally exhibits a high frequency oscillation which is probably caused by rain penetration. This may damage fluxes on the affected runs, although it is unlikely to be correlated with vertical velocity.