NASA Snow and Ice Products

NASA Remote Sensing TrainingGeo Latin America and Caribbean Water Cycle capacity Building Workshop

Colombia, November 28-December 2, 2011

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A project of NASA Applied SciencesA project of NASA Applied Sciences

What is Ice? When a mass, layer, or surface of water water freezes into solid at cool temperature

What is snow?

When water vapor freezes directly into ice crystals -- the process known as deposition

Snowflakes are the aggregation of many ice crystals

Snowfall is when snowflakes precipitate out of clouds

DefinitionsSea Ice

Snow on mountains

Lake Ice

Snow and Ice in the Climate System

They store water from days to weeks (snowfall and accumulation, lake ice) and years to centuries and longer (sea ice, glaciers, polar caps) time scales

They impact the reflected sun-light (albedo) and therefore, earth’s energy balance and temperature

Snowmelt and runoff – important source of ground water, streams and rivers

NASA Snow Products Available from Satellites and Models

Snow Cover: Fractional area covered by snow (fraction or %)

Surface Snowfall Rate: Amount of snow received at surface per unit area and time (Kg/m2/hour)

Snow Mass: Amount of snow per unit area per unit depth (Kg/m2)

Snow Depth: Distance between the earth and top of snow layer (m)

Snow Water Equivalent (SWE): Measurement of the amount of water contained in snow pack or depth of water that would theoretically result if the whole snow pack instantaneously melts. ( kg/m2 or m)

Sea Ice Extent: Ocean surface area covered by ice (Km2)

NASA Snow Products

• NASA provides snow products derived from satellite measurements and atmosphere-land models

• Satellite-derived and model-derived snow products provide excellent spatial coverage and uniform temporal coverage

Satellite observations of snow-cover, mass, and depth can be very useful in mountain areas where in-situ measurements are very difficult.

• Models are particularly useful in estimating snow-melt – important for its impact on run off and stream flow

• Long-term, global coverage of snow products from satellites and models are crucial for detecting and understanding Climate variability and change

NASA Snow Products Covered in this TrainingFor a complete list go to: http://water.gsfc.nasa.gov

And click on Training Materials

Snow Cover MODIS/Terra and Aqua, MERRA

Sea Ice Extent MODIS/Terra and Aqua

Surface Snowfall MERRA

Snow Water Equivalent AMSR

Snow Mass MERRA

Snow Depth MERRA

Products Source

Aqua Advanced Microwave Scanning Radiometer for EOS (AMSR-E)

• Flying on NASA’s Aqua satellites

• Provides rainfall, snow/ice, ocean surface temperatures, total column atmospheric moisture

• Twelve-channel, six-frequency, passive-microwave 6.925, 10.65, 18.7, 23.8, 36.5, and 89.0 GHz

Terra and Aqua MODerate Resolution Imaging Spectroradiometer (MODIS)

• 36 spectral bands ranging from 0.41 to 14.385 microns.

• Many applications, including clouds, snow/ice, vegetation, aerosol

• Available in various resolution (depends on product)

Arctic Sea Ice from MODIS

From Dorothy Hall NASA-GSFC

MODIS Snow Products Data Access and Visualization

MODIS Snow Products are available from National Snow and Ice Data Center http://nsidc.org/

MODIS snow cover can be visualized on Google Earth maps at http://nsidc.org/data/virtual_globes/index.html

MODIS Snow Products Data Access and Visualization: NASA LANCE

Go To:http://lancedev.eosdis.nasa.gov/tools/hazards-and-disasters/

In Step 1 Select: All Products

Scroll Down and click on Launch WMS

You will get a map, Click on Layers (upper right) and Select the layer you want

To download the image: Hold the Shift key and with the mouse draw a square of the area you want to visualize

• An atmospheric model using the Goddard Earth Observing System Data Assimilation System Version 5 (GEOS-5)

• Blends output data of the GEOS model with vast quantities of observational data

• Focuses on historical analyses of the water cycle on a broad range of weather and climate time scales (hours to years) and places the NASA satellite observations in a climate context

MERRA

Monthly Snow Cover Over Chile

Snow Cover : July-August 2009

Snow Cover over Chile:2001-2011

MERRA Snow Products

The following products are available from MERRA at 2/3° x 1/2° (approximately 75x50 km) spatial resolution and monthly temporal resolution from 1979 to present:

Snow Cover Surface Snowfall Snow Mass Snow Depth

MERRA monthly snow products can be analyzed and visualized on Google Earth maps by using NASA Giovanni tool:http://disc.sci.gsfc.nasa.gov/giovanni/overview/index.html Under Meteorological Portal – MERRA: 2D Monthly

MERRA Snow Products Data Access and Visualization

MERRA Snow Products are available for downloading in HDF format from National Snow and Ice Data Center http://mirador.gsfc.nasa.gov/

Users can choose spatial domain and temporal sub-sets to reduce data volume for downloading

NASA Snow Products Help monitoring/predicting River flow

Monthly Discharge at eight locations along American River, California (USA) for 2005 (blue) and 2007 (red)

Monthly Discharge (m3/s) from Stream Gauges American River originates in the Sierra Nevada mountains. The spring season discharge in the river shows significant correlation with the snowfall over Sierra Nevada during previous winter

Larger amount of winter season snowfall in 2005 over Sierra Nevada Mountains resulted in larger stream flow rates in the American River, California (USA), during subsequent spring season, compared to 2007.

MERRA Snow Depth 2005 and 2007 MERRA Snowfall Rate 2005 and 2007