Cold Land Processes Field Experiment Plan - December 7, 2001

 

EXECUTIVE SUMMARY


The Cold Land Processes Field Experiment (CLPX) has been designed to advance our understanding of the terrestrial cryosphere. Developing a more complete understanding of fluxes, storage, and transformations of water and energy in cold land areas is a critical focus of the NASA Earth Science Enterprise Research Strategy, the NASA Global Water and Energy Cycle (GWEC) Initiative, the Global Energy and Water Cycle Experiment (GEWEX), and the GEWEX Americas Prediction Project (GAPP). The movement of water and energy through cold regions in turn plays a large role in ecological activity and biogeochemical cycles. Quantitative understanding of cold land processes over large areas will require synergistic advancements in 1) understanding how cold land processes, most comprehensively understood at local or hillslope scales, extend to larger scales, 2) improved representation of cold land processes in coupled and uncoupled land-surface models, and 3) a breakthrough in large-scale observation of hydrologic properties, including snow characteristics, soil moisture, the extent of frozen soils, and the transition between frozen and thawed soil conditions. Synergistic advancement on these fronts requires the following four major science questions to be addressed together:

  1. Process Understanding. How do the extent and evolution of snow and frozen landscapes affect fluxes, storage, and transformations of water, energy, and carbon?

  2.  
  3. Spatial Variability. At what scales does spatial variability of key state variables in the terrestrial cryosphere, including snow characteristics, soil moisture, the extent of frozen soils, and the transition between frozen and thawed conditions, control fluxes and transformations of water, energy, and carbon, and can remote sensing resolve this variability at these scales?

  4.  
  5. Temporal Variability. What are the rates of change of the dominant cold land processes and can remote sensing resolve these with sufficient accuracy to diagnose and improve land surface models?

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  7. Uncertainty. How do the various uncertainties associated with remote sensing observations and models of cold land processes constrain/affect data assimilation and the ability to improve prediction?
The Cold Land Processes Field Experiment is designed to address these four questions.

The CLPX Plan has been developed through the efforts of more than 80 scientists that have participated in the NASA Cold Land Processes Working Group (CLPWG). This group, sponsored by the NASA Land Surface Hydrology Program, is charged with the task of assessing, planning and implementing the required background science, technology, and application infrastructure to support successful land surface hydrology remote sensing missions, in support of the goals of the NASA Earth Science Enterprise Research Strategy for 2000-2010. The need for a comprehensive field experiment to develop an improved understanding of cold land processes in relation to microwave remote sensing was identified in early 1998, as a result of NASA post-2002 mission planning. Since then, the CLPWG has conducted a series of open workshops and site visits to develop this Experiment Plan. No science teams have been specifically selected for designing and conducting the experiment. Instead, the contributions of many individuals have provided a plan to collect a comprehensive, legacy data set that will energize many aspects of cold land processes research. Broad, interdisciplinary participation in the experiment and use of the data sets is expected and encouraged.

The CLPX will focus 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 will particularly emphasize the development of a strong synergism between process-oriented understanding, land surface models and microwave remote sensing. The experimental design is 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 will be 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, dry and wet conditions are widespread. The experiment will be 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.

Chapter 1 provides an overview of the scientific objectives, approach, and risk reduction strategies for the experiment, and a summary of key measurements and data products. Chapters 2 and 3 describe the study areas and study periods. Chapters 4-6 describes the measurements and ancillary data sets that will be collected. Chapter 7 discusses field safety issues, an overarching concern throughout the plan. Chapter 8 describes the field operations plan for conducting the experiment. Chapter 9 describes data management plans. Chapters 10-11 presents measurement protocols and experiment logistics.