Lisa Darby and Taneil Uttal NOAA/Earth System Research Laboratory, Boulder, CO, USA
Matthew Shupe Von Walden Ed Eloranta Taneil Uttal James Campbell Masataka Shiobara
description
Transcript of Matthew Shupe Von Walden Ed Eloranta Taneil Uttal James Campbell Masataka Shiobara
Matthew Shupe Von Walden Ed Eloranta Taneil UttalJames CampbellMasataka ShiobaraSandy Starkweather
Cloud Occurrence and Phase at Arctic Atmospheric Observatories:
Further progress towards understanding Arctic clouds
AMS Polar Met. & Ocean. 2009Madison, WI
Observatories
Site Instruments DatesAtqasuk, AK, USA Ceilometer 1999 – Present
Barrow, AK, USA Radar, lidar, mwr, ceilometer, soundings
1998 – Present
Ny’Alesund, Norway Lidar 2002 – Present
Eureka, Canada Radar, lidar, mwr, soundings
2005 – Present
SHEBA, Arctic Ocean Radar, lidar, mwr, ceilometer, soundings
1997-1998
Summit, Greenland Ceilometer 2001-2002
Methods and Details
• “What is a Cloud?” It depends on your perspective and objective
• Clouds identified using thresholds for each sensor that aim to distinguish cloudy from clear sky signals.
• Different sensors at each site impact the results
• Phase classification requires radar, lidar, mwr, and radiosonde (only available at 3 sites)
Cloud Occurrence Fraction
Variability in time and space
Cloud “Phase” Type Fraction
All (black)Ice (blue)Mixed-Phase (orange)Liquid (red)Liquid present (red dash)
Barrow SHEBA Eureka
Vertical Distribution
Diurnal Cycle
AN
OM
AL
Y [
%]
Cloud Occurrence Fraction
C
loud
Fra
ctio
n A
nom
aly
[%]
Cloud “Persistence”
Phase vs. Temperature
• Detailed perspective from the surface complements satellite climatologies and in situ campaigns.
• Results are appropriate for model evaluation and comparisons with satellite retrievals.
• Need more observations to better establish baselines and to detect change. Needs: E. Arctic, over the sea-ice, longer records.
• Much of data used in this analysis is available at CADIS archive (www.eol.ucar.edu/projects/aon-cadis)
To Conclude