The NASA Cold Land Processes Field Experiment (CLPX)

The Cold Land Processes Field Experiment (CLPX) is a multi-year effort to develop the quantitative understanding, models, and measurements necessary to extend our local-scale understanding of cold-region water fluxes, storage, and transformations to regional and global scales. Particularly emphasized is the development of a strong synergism between process-oriented understanding, land surface models and microwave remote sensing within a broad range of physiographic regimes. Objectives of the CLPX include evaluation and improvement of algorithms for retrieving snow and frozen soil information from active and passive microwave sensors, evaluating the effects of sensor spatial resolution on retrieval skill, coupling forward microwave radiative transfer schemes to distributed snow/soil models to improve assimilation of microwave remote sensing data, and development of sensor specifications for a new space-flight mission to measure cold land hydrologic processes. The experimental design is a multi-sensor, multi-scale approach to providing the comprehensive data set necessary to address these objectives. A series of nested study areas, at five scales ranging from 1-ha to 160,000 km², provides the framework needed to address objectives concerning the scale and scaling of processes, measurements, and models. The largest of these, the Large Regional Study Area (160,000 km²), is located in north central Colorado and southern Wyoming. Within it is the Small Regional Study Area (37,000 km²). These two areas are the focus of satellite remote sensing data collection (MODIS, Landsat, Hyperion, SSM/I, AMSR, Radarsat, and others), and archival of mesoscale atmospheric model data sets (RUC2, LAPS, and RAMS). Nested within these are three 25-km x 25-km Meso-Cell Study Areas (MSA), that are the focus of airborne remote sensing data collection, including AIRSAR, POLSCAT, PSR-A, GAMMA, and AVIRIS. Within each of the three MSA are three 1-km x 1-km Intensive Study Areas (ISA), where spatially intensive ground observations of snow and soil characteristics are being collected. Within one of the three MSAs is the 1-ha Local Scale Observation Site (LSOS), where a comprehensive collection of snow, soil, and vegetation data is being collected in conjunction with ground-based active and passive remote sensing measurements. Field measurements were collected in two Intensive Observing Periods (IOP) in early 2002: winter (February 19-25, dry snow) and spring (March 25-April 1, wet snow). The measurements will be repeated on the same schedule in 2003. All CLPX data are being archived for public distribution at the National Snow and Ice Data Center.