IPCC models: Projected Arctic (60-90ºN) change of surface air temperature relative to 1980-2000
Impact of1 meter(3 feet)sea levelrise on FL
What are we doing about it (as scientists) ?
8 years of data from the North Slope of Alaska DOE/ARM site
SHEBA Surface Heat Budget of the Arctic
Early May~ 76N, 165 W
annual
IncreasedSpringAndSummerCloudiness
1982-1999AVHRR data(Wang&Key, 2003)
Persistent springtime cloud cover may advance snowmelt onset date (e.g., modeling study of Zhang 1996)
spring
summer
Surface-based Instrumentation: May 1-8 time series
35 GHz cloud radarice cloud properties
depolarization lidar-determined liquid cloud base
Microwave radiometer-derived liquid water paths
4X daily soundings. Near-surface T ~ -20 C, inversion T ~-10 C
-5-45 -20
1 2 3 4 5 6 7 8day
z
-30C
41 8
2
4
6
8
km
100g/m^2
day
-10C
lidar cloud base
May 4 Cloud Particle Imager data
…pristine ice particles from upper cloud
...super-cooled drizzle
How do clouds impact the surface ?
noon = 60o
Clouds decrease surface SW by 55 W m-2 ,increase LW by 49 W m-2
Surface albedo=0.86; most SW reflected backClouds warm the surface, relative to clear skies with same T& T & RH, by time-mean 41 W m-2* (little impact at TOA)
• Can warm 1m of ice by 1.8 K/day, or melt 1 cm of 0C ice per day, barring any other mechanisms !
Great websites with real-time data, historical fotos: