Methodology:

The data was gathered by installing the CPC inside the CASLab at Halley station, running a 3m length of antistatic tubing through a Brattberg port in the ceiling and allowing the remaining length of tubing to flow freely in the wind. This is to prevent icing of the inlet by allowing the inlet to stay out of the direct line of any snow or ice being blown around. Any movement from the wind should allow any hoar frost that builds up to fall off.

A large hopper of butanol was installed, raised slightly above the CPC in order to provide a constant source of butanol to the instrument through the part of the year where the station is unmanned.

The CPC data is similar to that of another dataset, using the same instrument at a similar location (Halley V, also on the Brunt Ice Shelf) during the CHABLIS campaign.

The data forms part of the wider Halley VIa CASLab dataset, which is for atmospheric chemistry data from Halley VIa's Clean Air Sector.

Data collection:

The data was logged by a TS7400 running v1.0.0 of the cpc-acquisitor software. The instrument used is a TSI CPC 3010.

Data quality:

Whilst processing the data, any line that included the string "LOVAC" or "NOTREADY" was excluded from the final dataset as the instrument would have been unable to function properly. In flagging the data, it was found the highest CPC counts relate to periods of low winds (measured from a nearby Automatic Weather Station), with clear changes in the count around 6kt and 11kt. Therefore, any data coincident with winds below 6kt was flagged as a "2", and any data below 11kt was flagged with a "1". Also, any data within 30mins of a "1" or a "2" was marked with the highest flag from that period. This is so that there is sufficient time to clear any pollutants. Finally, any data with a count higher than 10,000 was marked as a "2" as the CPC 3010 has a high coincidence count rate above this value.

Any missing values other than from the exclusion of "LOVAC" or "NOTREADY" data was from temporary powercuts.