The meteorological capabilities of the British Antarctic Survey in Antarctica

Steven Colwell

Rothera

JAWS (Just Another Weather Station) • Based around a Campbell CR1000 logger.• Druck pressure sensor.• Temperature is obtained via a PRT in an aspirated

radiation shield.• Humidity is obtained from a Vaisala HMP 45 probe

also in an aspirated radiation shield.• There are two wind sensors, a Vaisala WS 425 sonic

anemometer is the primary source of the wind data but there is also an RM young aerovane as a backup .

• A CNR1 solar radiation sensor is attached to the system that can measure incoming and outgoing long and shortwave radiation.

• Sunshine is recorded using a CSD1 sunshine detector.

• Data is logged every minute and displayed in realtime and software is run to allow a synoptic observation to be entered.

Radiosondes

• Radio-sondes are flow 4 times a week on Monday, Tuesdays, Thursday and Fridays using a Vaisala MW31 ground station, RS92 radio-sondes and 350gram balloons.

• Balloons are launched from a facility behind the hanger and the receiver antenna are mounted on the top of the hangar.

Precipitation measurements

• Biral LPS (Laser Precipitation Sensor)– Uses an infra-red laser to measure water droplets

and snow that pass between its sensor heads, it measures the reduction in the received signal and the length of time of the reduction and from this it can calculate the diameter of the particle and the fall speed

• Biral VPF 730 combined precipitation and visibility sensor– This operates using an infrared beam and looking

at off axis scatter to calculate visibility.– Precipitation type and intensity is calculated by

looking at the backscatter.

• It is felt that the LPS gives a more accurate measure of precipitation type and intensity as the VPF 730 seems to overestimate the amounts.

Tipping bucket snow-gaue• Snow is melted in a heated funnel and then

measured via a standard tipping bucket.• In winds above about 15 knots the snow can be

blown over the top.• A wind shield around the gauge is due to be

installed next season to see if that improves the amount of catch.

• It is very difficult to get a ground truth measurement to check these instruments against.

POM-01 sun photometer

• The POM-01 makes automatic measurements of solar radiation intensity in the wavebands 315, 400, 500, 675, 870, 940 and 1020 nm.

• It measures the extent to which light from the Sun is scattered as it travels through the Earth’s atmosphere, which allows the calculation of the size and density of the particles that are scattering the light (mainly things like sea salt, volcanic dust and man-made pollutants) .

• It can make measurements when the Sun is at an elevation above 5.7°.

SAOZ (System d' Analyse par Observation Zenitale)

• This instrument is run in the optical caboose at Rothera and measures sunlight scattered from the overhead sky which allows the calculation of how much ozone and nitrogen dioxide the light has passed through.

• Data is processed automatically and sent to NILU (Norwegian Institute for Air Research) for archiving.

Satellite Images

• Satellite images are received using our ARIES (Antarctic Reception of Images for Environmental Science) system.

• This has a 2.4m dish and the captured images can be displayed by using Dartcom software that is able to ingest the images.

• Images are also archived so that they can be used for research.

Forecasting capabilities• There are 2 Met Office forecaster based at

Rothera in the summer doing half a season each.• They have access to the data captured locally.• They use a HORACE system to display the data

from the Met Office forecast model, the system can also take in and display the data from the ARIES satellite receiver system.

• The forecaster also has access to the AMPS output so this can be used alongside HORACE.

Halley

• Halley is currently in a partial shutdown phase during the building of our new Halley 6 station.

• We are still making meteorological measurements using a Campbell AWS with a CR10X logger inside. The system measure pressure, temperature, humidity, wind speed and wind direction and these data are transmitted via a radio link back to the station so that hourly synoptic messages can be constructed.

• Radio-sondes are flow 6 times a week (every day except Sunday) using an MW31 ground station, RS92 radio-sondes and 350gram balloons. During the Halley summer season (December to mid February).

• A cloud-base recorder is also operated at Halley and a real-time display is available that can be used to give information to aircraft, the data is also archived so it can then be for research.

• Atmosphere aerosol is measured using a Prede POM-01 sun photometer.

• Ozone is measured using a Dobson spectrophotometer.

• Air samples are also collected for NOAA.• Snow samples are collected and sent back to

Vienna to be sampled for radioactive isotopes.

King Edward Point

• Meteorological measurement are made at KEP using a Vaisala MILOS 520 which measures pressure, temperature, humidity, wind speed, wind direction and sunshine.

• Precipitation is measured using a Biral LPS.

Bird Island

• Meteorological measurements are made at Bird Island using a Vaisala MILOS 520 which measures pressure, temperature, humidity, wind speed, wind direction and sunshine.

Questions

• www.antarctica.ac.uk• src@bas.ac.uk