All scientific data collected by the Australian Antarctic program (AAp) are eventually described in the Catalogue of Australian Antarctic and Subantarctic Metadata (CAASM). CAASM can be used to search through AAp data descriptions, and it also provides links to access publicly available datasets, which can either be immediately downloaded or obtained from the Australian Antarctic Data Centre (AADC).
This project wound up at the end of the 2011/2012 Antarctic season. Data have continued to be collected beyond 2012-06-30 under a new project - 4292, The Antarctic Clouds and Radiation Experiment (ACRE).
The CloudCam system captures timelapse images of the sky above Davis Station, Antarctica. So far it has been used to detect both noctilucent clouds (NLC) during summer and polar stratospheric clouds (PSC) during winter but it is also capable of imaging aurorae and tropopsheric clouds. The CloudCam system sits in a dome in the SAS building at Davis and consists of a camera, a motorised pod, a standard camera tripod and a standard PC which drives the image capture process and receives the imagery. Image capture process is driven by automated scripts on the PC which are executed as scheduled jobs using MacroScheduler software. All images are directly transferred to the PC where they are stored and processed by the scripts (no images are stored in the camera flash memory). The camera is powered from a mains outlet and connects to the PC using a standard USB 2.0 cable.
MacroScheduler sripts perform the following tasks:
- capture an image at user specified frequency,
- transfer image to the PC,
- time stamp the image with a user specified stamp,
- rename the image file to YYYYMMDD_HHMM.JPG,
- move the image file to the appropriate directory (YYYYMMDD),
- every 24 hours make a timelapse movie of the images for a complete UTC day, and
- create a new directory as required.
The scripts also periodically close and restart the Canon Remote Capture software. This is a workaround for a bug which periodically freezes the Remote Capture software unless it is restarted. The PC time is synchronised to the Davis SAS NTP server and all image timestamps derive from the NTP time. Currently the camera azimuth is fixed but the TrackerCam software can drive the motorised pod for azimuth tracking (eg. when the sunrise azimuth changes rapidly after the polar night and during the spring when PSCs are are still present).
Image quality can vary depending on weather conditions - eg snow, or ice build-up may obscure the images.
The present camera (2011) is a Canon PowerShot S3 IS digital camera.
The camera used in 2004 and 2006 was a Canon EOS300D.
Taken from the instruction manual:
The camera used in 2004 and 2006 is a Canon EOS300D with a standard 18-55mm f/3.5-5.6 lens and a 58mm HOYA PL-CIR polariser. At 18mm focal length and 28 mm equivalent long side the diagonal angle of field of view at infinity is 100.48 degrees.
Typical settings for polar stratospheric cloud season (starting in May) have been as follows:
- program = AE
- shooting mode = A-DEP
- AF = manual focus
- evaluative metering mode
- white balance = auto
- ISO 200-400
- exposure bracketing = +1/3 to -2/3 (increase stop in July/August)
- focal length = 18mm
- image size = 2048x1360 (medium), image quality = fine
Focussing is a process of trial and error once the camera is sitting on the tripod in the dome. Set the lens to MF mode, adjust the focal length as required and then check the focus by taking test shots with the Canon Remote Capture software. To do this start the Canon Remote Capture software, click "yes" for connecting to the camera and then press the "release" button to acquire an image. Images are stored in the directory specified in the preferences for the Remote Capture Software (Save - RemoteCapture - File/Preferences). Delete the images once you are finished.
These data are stored on Australian Antarctic Division servers at \\aad.gov.au\files\ATMOS\Data\Davis_CloudCam. Contact the Australian Antarctic Data Centre for access.
This data set conforms to the CCBY Attribution License
Please follow instructions listed in the citation reference provided at http://data.aad.gov.au/aadc/metadata/citation.cfm?entry_id=ASAC_737_lidar_cloudcam when using these data.