PALAOA - Transmitting live from the Ocean below the Antarctic Ice
Overview PALAOA area
- OGG-Vorbis live audio stream - provides better sound quality
Most recent spectrogram from the under ice hydrophone. Click to listen.
Providing an acoustic live stream of the Antarctic underwater soundscape is a formidable challange. After all, more than 15000 km lie between Antarctica and our institute in Germany. Underwater sound is recorded by means of two hydrophones by PALAOA, an autonomous, wind and solar powered observatory located on the Ekström ice shelf (Boebel et al., 2006). The data stream is transmitted via wireless LAN from PALAOA to the German Neumayer Base. From there, a permanent satellite link transmits the data to the AWI in Germany.
Please note, this transmission is not optimized for easy listening, but for scientific research. It is highly compressed (24kBit Ogg-Vorbis), so sound quality is far from perfect. Additionally, animal voices may be very faint. Amplifier settings are a compromise between picking up distant animals and not overdriving the system by nearby calving icebergs. So you might need to pump up the volume - but beware of sudden extreamely loud events.
A constant hiss pervading the signal is partly due to electronic noise as we push the hydrophone amplifiers to their limits, but also the natural ocean background noise made audible here through the use of ultra sensitive hydrophones. Additional broad band noise caused by wind, waves and currents adds to it on occasion. There a three sources of click-like interference: switching relais, electrostatic discharges caused by snow drift, and sferics produced by thunderstorms ten thousands of kilometers away. Due to the limited bandwith of the satellite link, jamming of the WLAN link due to storms, or energy shortage, the connection might temporarily be down or scrammed. In this case, please dial in later!
All material © 2008 AWI