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CONTENTS

0. Executive Summary
1. Overview
    1.1. Scientific Objectives
    1.2. Approach
    1.3. Summary of key measurements and data products
2. Soil Moisture and Temperature
    2.1. Introduction
    2.2. Electronically Scanned Thinned Array Radiometer (ESTAR)
    2.3. C Band Dual Polarization Observations
    2.4. Scanning Low Frequency Microwave Radiometer (SLFMR)
    2.5. Thermal Infrared Multispectral Scanner (TIMS)
    2.6. Split Window Thermal Infrared Radiometer (SWTIR)
    2.7. Soil Moisture Sampling
        2.7.1. Surface Soil Moisture Sampling
            2.7.1.1. Site Selection
            2.7.1.2. Sampling Plan
                2.7.1.2.1. Gravimetric Surface Sampling
                2.7.1.2.2. TDR Surface Sampling
                2.7.1.2.3. Bulk Density and Surface Roughness
        2.7.2. Profile Soil Moisture and Temperature Sampling
            2.7.2.1. DOE ARM CART
            2.7.2.2. USDA ARS SHAWMS
            2.7.2.3. Oklahoma Mesonet
            2.7.2.4. Cross Calibration with TDR Method
            2.7.2.5. Dielectric Profile Stations
    2.8. Truck Based Microwave Radiometry
3. Vegetation and Land Cover
    3.1. Vegetation Sampling
        3.1.1. Sampling Plan
        3.1.2. Resource Requirements
    3.2. Land Cover Classification
    3.3. CASI Aircraft Based Multispectral Data Collection
4. Soil Physical and Hydraulic Properties
    4.1. Introduction
    4.2. Soils of the Region
    4.3. Soil Survey Resources
        4.3.1. SSURGO
        4.3.2. STATSGO
        4.3.3. MIADS
        4.3.4. ARS Little Washita
    4.4. Soil Characterization Data
        4.4.1. NRCS
        4.4.2. Oklahoma State Mesonet
        4.4.3. ARS Little Washita
        4.4.4. Sampling of Soil Physical and Hydraulic Properties Protocol
            4.4.4.1. Sites
            4.4.4.2. Sampling Techniques
                4.4.4.2.1. Core Extraction
                4.4.4.2.2. Surface Characterization
            4.4.4.3. Laboratory Techniques
    4.5. Topographic Data
        4.5.1. USGS 1 km and 3-arc second
        4.5.2. ARS Little Washita 30 m
5. Planetary Boundary Layer Observations
    5.1. Water Vapor Profiles
    5.2. Airborne Fluxes
        5.2.1. NRC Twin Otter
        5.3.2. ATDD Long-EZ
    5.3. Surface Flux Measurements
    5.4. Atmospheric Soundings
6. Satellite Data Acquisition
    6.1. Landsat TM
    6.2. Priroda
    6.3. AVHRR
    6.4. Radar Satellites
    6.5. SSM/I
    6.6. GOES
7. DOE ARM CART Program
8. Geolocation of Ground Sites
9. Operations
    9.1. Experiment Management
        9.1.1. Aircraft Coordination and Plans
        9.1.2. Ground Observations and Sampling
    9.2 Safety
        9.2.1. Field Hazards
            9.2.1.1. Chiggers
            9.2.1.2. Ticks
            9.2.1.3. Snakes
        9.2.2. Drying Ovens
    9.3. Site Access
    9.4. Communications
    9.5. Briefings
10. Data Management and Availability
11. Science Investigations
12. Sampling and Measurement Protocols
    12.1. Surface Gravimetric Soil Moisture
        12.1.1. Field Sites
        12.1.2. Profile Sites
    12.2. Bulk Density
        12.2.1. The Bulk Density Apparatus
        12.2.2. Selecting and Preparing an Appropriate Site
        12.2.3. Bulk Density Procedure
        12.2.4. Potential Problems and Solutions
    12.3. Vegetation
13. Local Information
    13.1. Hotels
    13.2. Maps
14. References
15. List of Participants

0. EXECUTIVE SUMMARY

The Southern Great Plains 1997 (SGP97) Hydrology Experiment originated from an interdisciplinary investigation, "Soil Moisture Mapping at Satellite Temporal and Spatial Scales" (PI: Thomas J. Jackson, USDA Agricultural Research Service, Beltsville, MD) selected under the NASA Research Announcement 95­MTPE­03. The main objective of this investigation was to establish that the retrieval algorithms for surface soil moisture developed at higher spatial resolution using truck­ and aircraft­based sensors can be extended to the coarser resolutions expected from satellite platforms. As part of this investigation, a field experiment, built upon the success of a previous experiment of much smaller scale (Jackson et al., 1995), was proposed for 1997. The core of the 1997 experiment involves the deployment of the L­band Electronically Scanned Thinned Array Radiometer (ESTAR) for daily mapping of surface soil moisture over an area greater than 10,000 km2 and a period on the order of a month. Motivated by the wide­spread interest among hydrologists, soil scientists, ecologists and meteorologists in the problems of the

estimation of soil moisture and temperature states at the continental scale and the coupling between land­surface and the atmosphere (Wei, 1995), a workshop was held in Beltsville, Maryland, on August 26­28, 1996; the main purpose of this workshop was to identify additional complementary measurements that would promote the overall utility of the experimental data in interdisciplinary research. Further deliberation of the suggestions and recommendations made at the workshop led to the plan described herein which is really the result of the abundant individual and institutional support and cooperation.

The SGP97 Hydrology Experiment as it has developed is a collaboration by a team of interested scientists largely based on existing sponsored scientific investigations and research projects; no science teams were specifically selected for designing and executing the experiment. Cooperation and contributions by many (either individually or as a group), have resulted in a comprehensive opportunity for multidisciplinary scientific research. Research use of the experimental data is encouraged; care is given to data management to allow easy access upon the completion of quality control and cross calibration and validation.

Chapter 1 provides an overview of the scientific issues and objectives of SGP97, the approach taken in designing the experiment, and a summary of key measurements and data products. Chapters 2­5 contains detailed descriptions of the ground and aircraft based data and information to be collected and assembled pertaining to the soils, soil moisture and temperature, vegetation and land cover, as well as the atmospheric boundary layer during SGP97. Satellite data acquisition is described in Chapter 6. This document is expected to be revised as additional details are resolved with a final version expected in June, 1997.