Four-Dimensional Model Assimilation of Data: A Strategy for the Earth System Sciences -- Copyright -- Contents -- Executive Summary -- CONCLUSIONS -- RECOMMENDATIONS -- 1 Introduction -- CONCEPT OF GEOPHYSICAL MODEL DATA ASSIMILATION -- ASSESSMENT OF DATA ASSIMILATION IN ATMOSPHERIC SCIENCES -- DATA ASSIMILATION VIEWED AS PART OF A SYSTEMATIC LEARNING PROCESS -- CURRENT STATUS OF DATA ASSIMILATION -- APPLICABILITY OF DATA ASSIMILATION TO THE EARTH SYSTEM SCIENCES -- 2 Data Assimilation Development -- INTRODUCTION -- PRINCIPLES AND METHODS -- CONTINUOUS DATA INSERTION -- RESEARCH AND DEVELOPMENT IN DATA ASSIMILATION: THE KALMAN FILTERAND ADJOINT METHODS -- 3 Current and Future Applications of Model Assimilation Systems -- GLOBAL ATMOSPHERIC CIRCULATION -- MESOSCALE ATMOSPHERIC CIRCULATIONS -- PHYSICAL OCEANOGRAPHY -- HYDROLOGICAL CYCLE -- Atmospheric Subsystem -- Land Surface Subsystem -- Ocean Surface Subsystem -- GLOBAL PRECIPITATION -- LARGE-SCALE FIELD EXPERIMENTS AND BIOSPHERIC STUDIES -- ATMOSPHERIC CHEMISTRY -- EARTH OBSERVING SYSTEM -- USE OF MODEL-ASSIMILATED DATA SETS FOR RESEARCH -- 4 Needs for the Future for Model-Assimilated Data Sets -- RESEARCH PROBLEMS -- Synotic Systems -- Planetary Waves -- Low-Frequency Variability -- Atmosphere-Ocean Interactions -- Atmosphere-Land Interactions -- Dynamics-Chemistry-Radiation Interactions -- Hydrology -- DATASETS NEEDS BY TIME SCALES -- 0 to 3 Days -- 3 to 10 Days -- 10 to 100 Days -- 100 to 1000 Days -- 1000+ Days -- REQUIREMENTS FOR DATA AND COVERAGE -- General Principles -- General Specifications -- 5 Quality Control and Validation of Observations, Analyses, and Models -- DATA MONITORING -- EPISODIC MODEL REJECTION OF DATA -- VALIDATION OF REMOTELY SENSED EARTH OBSERVING SYSTEM DATA -- VALIDATION OF MODEL-ASSIMILATED ANALYSES -- VALIDATION OF FORECAST MODELS.

6 Status of Data Archives, Access, and Future Directions -- AVAILABLE ANALYSES AND OBSERVATIONS -- Atmospheric Analyses -- Ocean Analyses -- Hydrological Analyses -- Paleoclimate Reconstructions -- Surface Observations (Meteorology, Hydrology, Oceanography) -- Upper-Air Data (Meteorology) -- RESOURCES NEEDED FOR ARCHIVING MODEL-ASSIMILATED DATA SETS -- Resources Needed to Prepare Older Observed Data -- ARCHIVE METHODS AND INSTITUTIONAL ARRANGEMENTS -- FUTURE DIRECTIONS -- Access to Model Data and Observations -- Locate More Data at the Scientist's Site -- Software for Data Display and Manipulation -- National Weather Service Modernization Program -- Advances in Computer Technology -- 7 Conclusions and Recommendations -- CONCLUSIONS -- RECOMMENDATIONS -- References -- List of Acronyms.