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The NASA Cold Land Processes Experiment (CLPX) focused on developing the
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 particularly emphasized the
development of a strong synergism between process-oriented understanding, land
surface models and microwave remote sensing. The experimental design was 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 focused on two seasons:
mid-winter, when conditions are generally frozen and dry, and early spring,
a transitional period when both frozen and thawed, dry and wet conditions are
widespread. The experiment was conducted in the central Rocky Mountains
of the western United States, where large physiographic gradients provided
a rich array of different terrain, snow, soil, and ecological characteristics
to be examined.
The specific objectives of the Cold Land Processes Field Experiment were 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 a) improve the representation of subgrid-scale variability of snow and frozen soil in coupled and uncoupled land surface models, and b) 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.
List of Acronyms
CLPX = NASA Cold Land Processes Experiment
IOP = Intensive Observation Period
ISA = Intensive Study Area
LRSA = Large Regional Study Area
LSOS = Local Scale Observation Site
MSA = Meso-cell Study Area
For further information about CLPX, please visit the CLP
Mission Site.
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