1. Australian Antarctic Data Centre
2. Discover and Manage Data
3. Records
4. SIPEX_II_Aerosols

Description

The current dataset includes total aerosol count from two different Condensation Particle Counters (CPCs). The two CPCs measure total aerosol number in two different size ranges:
- TSI Model 3025A measures particles with diameters larger than 3 nm (files are in the 3025_3nm folder)
- TSI Model 3772 measures particles with diameters larger than 10 nm (files are in the 3772_10nm folder)
The two CPCs are measuring from the same sample air and as such, the difference between the two measurements gives a measurement of total aerosol concentration in the 3-10 nm size range, known as the nucleation mode.

Instrument setup:
The instruments are setup inside an insulated shipping container mounted on the hatch covers directly aft of the forecastle. A 100 L pump is used to pull sample air from a 3 m high mast located on the starboard side of the forecastle. The air is pulled through 17 m of 50 mm antistatic (copper coil) polyurethane tubing and 2 m of 50 mm stainless steel pipe for connection and extensions. A 1 m length of one quarter inch stainless steel tubing penetrates into the container and directly through the wall of the polyurethane tubing for sampling off the primary flow to the CPCs. The inserted stainless steel tubing is oriented in such a way that sampled aerosol experience minimal turns to avoid sample loss. Approximately 1.7 m of flexible conductive tubing extends to a Y-piece which directs flow into each CPC. Butanol contaminated exhaust from the CPCs is pushed out of the container by two 10 LPM pumps.

Data Processing:
Raw data is calibrated for each instrument's recorded flow rate, and an inlet efficiency to correct for losses in the long inlet. Data is then resampled to minute time resolution, and filtered for logged events, wind directions which sampled ship exhaust, and outliers in the dataset. This produced a dataset which represented the sampling of clean Antarctic background atmosphere.

The dataset includes both aerosol number concentrations from each instrument giving total number of particles above 3 nm and 10 nm respectively, as well as the different between these values, which gives a measure of newly formed particles in the nucleation mode between 3-10 nm (New Particle Formation, NPF). Associated uncertainties are included in the dataset.

Quality

Low temperatures (0 degrees C) were experienced in the container lab on the 28/9/2012 which caused issues with butanol supersaturation and optics temperatures, as well as electronics power failures.

After the 28th September temperature drop which took out our local Uninterrupted Power Supply (UPS). Connection to ship UPS occurred on the 1/10/2012. Possible instrument outages between.

Wind direction greatly affects sample air, with apparent wind directions from the 90 to 270 degrees East of North having possible contamination from ship exhaust.

Severe instrument issues were encountered on the 3025 on the 24th October, which meant that data may be problematic after this point. Please see log for details and extracted data files for reported faults. These issues became terminal and combined with low levels of butanol supply remaining, led to early pack up of the instrumentation on the 3rd November.

Access

These data are not yet publicly available.

Temporal Coverages

• Start date: 2012-09-23 - Stop date: 2012-10-24

Spatial Coverages

Science Keywords

• EARTH SCIENCE > ATMOSPHERE > AEROSOLS

Use Constraints

This data set conforms to the CCBY Attribution License
(http://creativecommons.org/licenses/by/4.0/).

Please follow instructions listed in the citation reference provided at http://data.aad.gov.au/aadc/metadata/citation.cfm?entry_id=SIPEX_II_Aerosols when using these data.