Please enable JavaScript.
Coggle requires JavaScript to display documents.
Clouds & their role in the cryosphere (How clouds impact cryosphere…
Clouds & their role in the cryosphere
Crysosphere
The frozen water part of Earth system (where ice is)
Alps
Himalayas
Antarctica
Canada
Greenland
Ice and snow on land
is one part of Cryosphere- continental ice sheets, ice caps, glaciers, snow, permafrost
Other part of Cryosphere is the
ice found in water
- frozen parts of ocean, rivers, and lakes.
Cryosphere today:
Arctic sea ice volume data shows large decrease due to warm Arctic winter (lowest amounts ever seen)
Halley station is temporary closed for Souther winter- 1st break in 60 continuous years of human presence
Growing no. of melt ponds, force way into ice cracks causing ice shelves to weaken & collapse
Larson B ice shelf collapsed in only 5 weeks- existed for at least 10,000 years
Greenland's ice sheet contains 10% of Earth's glacial ice
How clouds impact cryosphere
Cryosphere too cold to rain, global warming will cause increased rainfall
Source: Precipitation -> mass budget
Reflect sunlight
Sink: radiation -> energy budget
Modulate the amount of heat and melting
observing clouds
Clouds in the cyrosphere are unique as they are mostly ice- temps are below freezing- any liquid clouds are unstable
Measure clouds: using satellite and radar images, remote sensing from ground or space
Remote sensing=
Measuring the physical properties of an object or medium, using a sensor that is at some distance from the object or medium
Active remote sensing: detector emits radiation for artificially illuminate a scene (cameras use flashes)
LIDAR
- radiation beams travels, photons interact with layer, light absorbed and scattered by atm, scattered light returns to LIDAR, attenuated light continues to next layer of atm
Passive remote sensing: detector relies upon external source of illumination (visible image record reflected sunlight)
Attributes of clouds
Microphysics-
whats going on inside clouds
Dynamics-
large scale features of clouds
Radiative cooling
Surface layer-
how clouds impact surface
Difference between liquid vs ice
LIDAR depolarisation ratio
Highly polarised light in one plane interacts with cloud- measures parallel and perpendicular components to original polarisation
Cloud droplets don't have depolarisation ratio: tiny and spherical
Ice crystals: not spherical so have ratio
Maxwel's equations, EM waves, polarisation
EXAMPLE
Extreme weather: Altitude 12851ft and -135 F
Summit camp
400km from coast
Greenland ice sheet project II ice core (1993)
Peak of Greenland ice cap
NSF's ICECAP project (2010-now)
Melting at Summit (2012)
large amounts of liquid in clouds at low altitudes
Liquid clouds occur all year round- especially in summer
July 2012- around 90% melt, compared to 25% average between 1981-2010
Warm low level clouds w/ high albedo reflect more radiation vs cold upper level cloud w/ low albedo absorbing more