Ice clouds

Many hours of LIDAR (LIght Detection And Ranging) operation at Davis resulted in the first ground-space coincident observation of 'Noctilucent clouds – when viewed from the ground' or 'Polar Mesospheric Clouds – when viewed from space' over Antarctica.

These very thin ice clouds indicate temperatures lower that -130°C where they form near 83 km altitude. Increasing occurrence of noctilucent clouds is expected from the cooling effect of increasing carbon dioxide at high altitudes.

A unique polar mesospheric cloud captured on the lidar on New Years Eve/Day persisted for 22 hours and almost jumped off the brightness scale. Our atmospheric radar also recorded related intense 'blobs' or to the Ice, Ocean, Atmosphere and Climate scientists 'Polar Mesosphere Summer Echoes'.

Amazingly, orbiting Davis at this time was the 'Aeronomy of Ice in the Mesosphere (AIM)' spacecraft – which recorded its brightest and thickest PMC layer to date.

The study of these ice layers that form at the edge of space in the altitude range of 80 to 94 km using the Davis lidar and radars, and the NASA AIM spacecraft instruments - is focussed on determining whether their increasing brightness and latitude coverage are an indicator of climate change in the atmosphere.

This research is part of the Ice, Ocean, Atmosphere and Climate program contribution to the International Polar Year science objectives.

Image of the Davis Station LIDAR laser flashlamp
The Davis LIDAR laser flashlamp keeps on glowing.
Photo: Noel C
Image of LIDAR chart showing exceptional clouds in the mesopause region (80-90 km above the surface) over Davis on New Year's Eve
Exceptional clouds in the mesopause region (80-90 km above the surface) drifting over Davis on New Year's Eve revealed by lidar.
Photo: Andrew C, Didier M, Andrew K, Ray M, Vladimir L
Adélie Penguins gather near MST atmospheric radar antennas
Adélie Penguins gather near MST atmospheric radar antennas.
Photo: Mark M

The altitude versus time plot of the New Years PMSE as detected by radar
The altitude versus time plot of the New Years 'Polar Mesosphere Summer Echo' as detected by radar.
Photo: Ray M
Image of the Aeronomy of Ice in the Mesosphere (AIM) spacecraft
The Aeronomy of Ice in the Mesosphere (AIM) spacecraft orbits 600 km above Davis.
Photo: NASA
PMC over Antarctica on New Years Eve acquired by the cameras on the AIM spacecraft
Polar Mesospheric Cloud over Antarctica on New Years Eve acquired by the cameras on the AIM spacecraft.
Photo: Larry Gordley/AIM team

More on the Lidar:

The LIDAR team broke a massive record in December - they collected over 235 hours of data for the month. The previous record was 205 hours, set in January 2006.

Some statistics...

  • 10 sessions in total averaging 24 hours of data in each
  • Longest run collected 60 hours and 50 minutes of data
  • Shortest run collected 4 hours and 32 minutes of data
  • 235 hours and 2 minutes worth of data in total
  • 259 hours and 55 minutes of laser running time
  • A laser duty cycle of 35% for the entire month
  • During the last 9 days of the month the laser was running 82% of the time; that's 178 hours

The average data total for December is roughly 45 hours (2001-2006), 235 hours is more than 5 times this amount.

This page was last modified on 18 January 2008.