AMSR-E Validation Data

Cryospheric Data

Cold Land Processes Experiment (CLPX)

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The NASA Cold Land Processes Field Experiment (CLPX) is focused on developing quantitative understanding, models, and measurements necessary to extend our local-scale understanding of water fluxes, storage, and transformations to regional and global scales. The experiment emphasized the development of a strong synergism between process-oriented understanding, land surface models, and microwave remote sensing. The experimental design consisted of a multi-sensor, multi-scale approach to providing the comprehensive data set necessary to address several experiment objectives. Within a framework of nested study areas ranging from 1-ha to 160,000 km2, intensive ground, airborne, and spaceborne observations were collected. Data collection focuses on two seasons: mid-winter, when conditions are generally frozen and dry, and early spring, a transitional period when both frozen and thawed, and dry and wet conditions are widespread. The experiment was conducted in the central Rocky Mountains of the western United States where large physiographic gradients provide a rich array of different terrain, snow, soil, and ecological characteristics to be examined.

The experiment was conducted between the Fall of 2001 and the Spring of 2003. Two Intensive Observation Periods (IOPs) were conducted each year: one during a dry period (February) and one during a wet period (March). The IOPs are conducted on the same day-of-year (DOY) schedule each year.

The specific objectives of the Cold Land Processes Field Experiment are to:

• Evaluate and improve snow water equivalent retrieval algorithms for space-borne passive microwave sensors such as SSM/I and AMSR-E.
• Evaluate and improve radar retrieval algorithms for snow depth, density, and wetness, and soil freeze/thaw status.
• Improve radar retrieval algorithms to enable discrimination of freeze/thaw status of different surfaces. For example, snow, soil, and vegetation.
• Examine the effects of scale (spatial resolution) on the skill of active and passive microwave remote sensing retrieval algorithms for snow and freeze/thaw status.
• Evaluate and improve spatially distributed, uncoupled snow/soil models and coupled cold land surface schemes from point scales to typical mesoscale grid-resolutions, typically 25 km.
• Examine the feasibility of coupling forward microwave radiative-transfer schemes to spatially distributed snow/soil models to improve assimilation of microwave remote sensing data.
• Examine the spatial variability of snow and frozen soil distributions in different environments, and improve the representation of subgrid-scale variability of snow and frozen soil in coupled and uncoupled land surface models, and improve the representation of orographic precipitation (snowfall) in atmospheric models.
• Examine methods of extending local-scale, process-oriented equations describing important cold-land hydrologic and boundary layer properties to larger scales typical of regional and global atmospheric and hydrologic models.

For complete information about the CLPX, please visit the CLPX Web site.