NASA Technical Memorandum 4679

Spaceborne Synthetic Aperture Radar : Current Status and Future Directions

A Report to the Committee on Earth Sciences

Space Studies Board

National Research Council

• D.L. Evans, Editor
• J. Apel
• R. Arvidson
• R. Bindschadler
• R. Carsey
• J. Dozier
• K. Jezek
• E. Kasischke
• F. Li
• J. Melack
• B. Minster
• P. Mouginis-Mark
• J. van Zyl

April 1995

NASA

Figures and figure captions only

Table of Contents

• Acknowledgments
• Discipline Panel Chairmen
• Preface

• 1--Executive Summary
  • INTRODUCTION
  • RECOMMENDATIONS

• 2--Ecology
  • INTRODUCTION
  • BACKGROUND
    • Radar Sensing of Vegetated Landscapes: Physical Basis
  • ROLE OF SAR
    • Land Cover Classification
    • Measuring Above-Ground Woody Plant Biomass
    • Delineation of Wetland Inundation and Vegetative Cover
    • Monitoring of Dynamic Processes in High-Latitude Ecosystems
  • SAR SYSTEM CONSIDERATIONS
    • Optimum System Parameters
    • Utility of Existing/Planned SAR Systems
  • RECOMMENDATIONS

• 3--Hydrology
  • INTRODUCTION
  • BACKGROUND
  • ROLE OF SAR
    • Soil Moisture Remote Sensing
    • Difficulties in Soil Moisture Remote Sensing
    • Field Measurements of Soil Moisture
    • Radar Observations for Soil Moisture
  • CURRENT AND PLANNED SAR ASSETS AND THEIR USE
  • RECOMMENDATIONS

• 4--Marine Science and Applications
  • INTRODUCTION
  • BACKGROUND
    • Scientific Objectives
    • Observational Results
    • Theoretical Developments
  • ROLE OF SAR
    • Open Ocean
    • Coastal Oceans and Marine Operations
    • Marine Boundary Layer Meteorology
    • Polar Oceans
  • CURRENT AND PLANNED SAR ASSETS AND THEIR USE
  • RECOMMENDATIONS

• 5--Ice Sheets and Glaciers
  • INTRODUCTION
  • KEY QUESTIONS
    • Are glaciers and ice sheets useful indicators of current climate change?
    • How do the ice sheets affect atmospheric and oceanic circulations?
    • What is the current mass balance of ice sheets and glaciers?
    • What are the controls on ice flow and are there inherent instabilities in ice flow that could lead to dramatic changes in the dynamics of ice sheets or glaciers?
    • How much of the heat absorbed by the surface snow pack is retained by the ice mass and how much escapes as meltwater?
  • ROLE OF SAR IN ANSWERING THESE QUESTIONS
    • Snow Facies
    • Seasonal Melt
    • Icebergs
    • Surface Morphology
    • Ice Velocity
    • Surface Topography
  • POSSIBLE ADDITIONAL USES OF SAR DATA
    • Is there a "best" SAR frequency for ice sheets and glaciers?
    • Can useful scientific information be obtained by studying polarization effects?
    • What are the physical processes that cause target decorrelation and what are their relative effects?
  • WHAT MUST BE DONE TO CONFIRM THESE POTENTIALS?
  • CURRENT SAR ASSETS AND THEIR USE
  • PLANNED FUTURE MISSIONS
  • RECOMMENDATIONS

• 6--Solid Earth Sciences and Topography
  • INTRODUCTION
  • BACKGROUND
  • CONTEXT FOR U.S. RADAR MEASUREMENTS
  • SCIENCE THEMES
    • Topographic Mapping and Crustal Motions
    • Regional Mapping
    • Quantitative Lithologic Mapping with SAR
    • Analysis of Geomorphic Processes
  • HOW COULD A NEW U.S. SAR CONTRIBUTE TO ANSWERING THESE SCIENCE QUESTIONS?
    • Capabilities of Current Radars
    • Development of a New U.S. Radar Satellite
  • RECOMMENDATIONS

• 7--SAR System Technology
  • INTRODUCTION
  • SCIENCE PANEL NEEDS SUMMARY
  • STRAWMAN SAR MISSION SCENARIO
  • RADAR SYSTEM TECHNOLOGY DISCUSSIONS
    • Antenna Technology Discussions
    • RF Electronics Technology Discussions
    • Digital Electronics Technology Discussions
    • Data Processing Systems
    • Other SAR System Technology Considerations
  • RECOMMENDED SAR TECHNOLOGY PROGRAM APPROACH

• 8--References
  • 2--Ecology
  • 3--Hydrology
  • 4--Marine Science and Applications
  • 5--Ice Sheets and Glaciers
  • 6--Solid Earth Sciences
  • 7--SAR System Technology

• Appendix A

• Appendix B
  • Microwave Bands Available for SAR

• Appendix C
  • ACRONYMS