The Knorr IMET data contained the needed parameters, but 89% of the wind compass data(a proxy for heading) was 0.0 degrees. This is unrealistic for a ship spending 3 months at sea cruise, so we consider this data to be erroneous. With erroneous data, true wind speed and direction cannot be calculated by the DAC. Thus, the following parameters have been omitted from the version 100 data files and this summary: wind compass, wind vane, platform relative wind direction, platform relative wind speed. True wind direction and true wind speed are in the final version as missing.

Despite the high percentage of flags, these data are in moderately good shape. One major problem with these data is that at random intervals, the values for LAT, LON, PL_CRS, and PL_SPD are 0.0 for extended periods of time. For cruises located in the Pacific Ocean, a 0.0 latitude, 0.0 longitude position is not possible, and holding a course at 0 at a speed of 0 is unlikely, so these data have been flagged as "J", erroneous data.

Other issues include the 197,634 "G" flags the prescreener added to the data. These were applied to P, T, T2, TS, and RH for values that were significantly below or above the climatological mean. These flags were left by the analyst as an indication of statistically extreme values.

In addition, the prescreener added 141,900 "B" flags to the data. RAD was assigned 125,640 "B" flags. Due primarily to a likely calibration problem with the radiation sensor. At night the pyranometer routinely recorded values less than 0.0 W/m2, which is the lower bound for solar radiation data. TS was also flagged with "B" flags 15,102 times due to sea temperature values that were below 0.0oC. These values occur around the coast of Antarctica where, due to salinity features of the ocean, the sea temperature can fall below the freezing point. P was flagged 1,158 times due to very low pressures that occured in this same region. The "B" flag is applied when the atmospheric pressure falls below 950mb. This in not an uncommon occurrence near 60o S. However, all "B" flags were left by the analyst to highlight these low pressure events.

The 6,629 "K" flags were added to RAD in response to a specific pattern in the data. The RAD for one day would show a normal dirunal cycle, with about 14 hours of sunlight. The next day, the cycle would show about 6-7 hours of sunlight, with radiation readings at or within 1 W/m2 of 0.0 W/m2 for the remaining time. The obvious conclusion is that the sensor is malfunctioning. There is no corroborating evidence that this is the case, plus the sensor works well the rest of the time, so this data cannot be marked with "M" or "J" flags.

Of the 2,221 "K" flags added to PRECIP, 1440 are a result of precipitation data on 02/23/93 that shows the syphon emptying at 20mm (normally it empties at 50mm). The emptying is not complete, however, as the level within the syphon does not go to 0. Instead, it goes to about 4mm and then shows a noise range as wide as 8mm. The other flags were added on 04/07/94 where the level of the rain in the syphon is once again questionable.

Spikes were applied most often to PRECIP. These are mostly the result of data readings going to 0 for 1 data point, then returning to the previous pattern, but they can also be caused by noise that ranged too far from the normal noise pattern. Spikes are also prevalent in LAT and LON. These are from ship positions that are reported as 0o lat-0o lon. Only the points that deviate from the pattern are flagged with "S". The rest are left as they were prescreened, with the "F", platform movement unrealistic flag. The spikes in the rest of the variables are not a result of any pattern or problem in the data. Rather they are spikes that are common to any electronically recorded data set.

The only significant flags left to discuss are the "I" flags. These were added to T or T2 anytime a drastic temperature change occurred.