The Cryosphere Flashcards
Cryosphere
Portions of the Earth’s
surface characterized by
frozen water, including:
- Snow
- Ice
- Ice sheets (small glaciers)and ice shelves(glacier over top of water connected to ice sheet)
- Glaciers
- Sea ice
- Permafrost(ground that is iced throughout the year)
Why Monitor the Cryosphere?
Very useful indicator of climate variability and change
* Community impacts
* Biodiversity impacts
Weather and climate prediction
* Storms
* Transportation
Significant freshwater storage
* Water resource management
* Ecosystem
* Hydrology
Historical Monitoring of the Cryosphere
- Systematic annual measurements since the 1940’s and 1950’s
provide powerful time series of changes in cryosphere conditions. - Glacial mass balance
- Glacial extent
- Sea-ice thickness
via Arieal Photography,repeat (terrestrial) Photogragy - could find the same location,Field Work(on the ground)
Monitoring the Cryosphere from Space
Landsat
* Fine/moderate spatial resolution
* Data back to the 70s & 80s
* Passive (provide spectral information)
MODIS
* Fine temporal resolution
* Applicable for imaging larger areas
* Passive (provide spectral information)
RADAR (RADARSAT & airborne/terrestrial RADAR)
* All weather system
* Uses microwaves
* Surface penetrating
-Active
Lidar (IceSat & airborne Lidar)
* Elevation
* 3D information on topography
-Active
Monitoring the Cryosphere from Space
Characteristics of the Cryosphere measured include snow/ice:
- Cover - RADARSAT
- Extent
- Depth - RADARSAT
- Type - Landsat or MODIS
- Age
- Movement- MODIS?, RADARSAT
Why do old/dirty glaciers have lower
reflectance than fresh snow?
- Impurities and debris cover
- Higher degree of surface
roughness
slide 15
because of these diffrence in spectrum signature can help to differs its type
Landsat: Passive
landset specifically as a spectral type of data as something that is measuring spectral type of data and spectral reflectance across diferent portions of the eletricalmagnetic spectrum is good in mapping things like snow and ice type
Landsat is good for this higher level of detail over a smaller area in terms of mapping and monitoring the cryosphere because of its moderate spatial resolution but not in bigger areas
daily scale
MODIS: Passive
give a daily imagening that (landsat dosn’t)
good at mesuring things that are happening at a high temporal scale,daily frequency
good at mesuring things at a global scale
RADARSAT:Active
* Estimation of snow mass
* use Backscatter(strengh of retern signal and where the target is )
* can mesure Ice cover
* use Backscatter
* can mesure Permafrost
* Ranging
* Quantify soil stability
* Important for northern
communities
- Ice flow mapping
- Backscatter and ranging
RADAR surface pernatratring capability is used via :
- Airborne(in a plane)
- Terrestrial RADAR(some one is pulling in the ground)
Lidar:Active
Airborne Lidar
* High resolution 3D information
IceSat
* Spaceborne Lidar
* Launched for monitoring cryosphere
* Also measures clouds and elevation
* IceSat-1 operated from 2003 – 2009
* IceSat-2 was launched in 2018
* Uses visible green laser pulses instead of infered
* 532nm
Why might IceSat use green light?
because ice and snow strongly reflect visible green light more so than near infared light thus allowing us with it to get a stronger return signal
can we measure depth is Lidar ?
yes 47:00
Advantages of Earth Observation Data for
Cryosphere
same advantages earth observation data in the biosphere and cryosphere
Depending on the dataset:
* Standardized data
* Efficient collection
* Coverage (in space)
* we can get different Resolutions
-Spatial
-Temporal
-Spectral
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