DURING INTERVALS OF INCREASED GEOMAGNETIC ACTIVITY THE INTENSITIES OF RELATIVISTIC ELECTRONS TRAPPED IN EARTH'S RADIATION BELTS VARY BY ORDERS OF MAGNITUDE. ELEVATED LEVELS OF ELECTRON RADIATION CAN DAMAGE AND DISABLE SATELLITES. TO MITIGATE HAZARDOUS RADIATION EFFECTS IT IS NECESSARY TO QUANTIFY AND PREDICT RADIATION BELT ENHANCEMENT EVENTS. WHILE MANY INDIVIDUAL MECHANISMS OF ELECTRON ACCELERATION AND LOSS HAVE BEEN IDENTIFIED THE NET EFFECT OF ALL PROCESSES ACTING IN CONCERT IS NOT UNDERSTOOD BECAUSE NO UNIFIED PHYSICS-BASED MODEL EXISTS IN WHICH ALL OF THESE EFFECTS ARE INCLUDED. THE PRIMARY GOAL OF THIS PROPOSAL IS TO PROVIDE A DATA-CONSTRAINED MODELING CAPABILITY FOR PREDICTION OF THE NEAR-EARTH RADIATION ENVIRONMENT INCLUDING ITS DYNAMIC VARIABILITY IN RESPONSE TO DIFFERENT SOLAR WIND DRIVING. OUR MODEL INCORPORATES ALL KEY ELECTRON ACCELERATION AND LOSS MECHANISMS BY COMBINING A SELF-CONSISTENT DESCRIPTION OF GLOBAL ELECTROMAGNETIC FIELDS THAT DRIVE CONVECTION AND RADIAL TRANSPORT WITH AN EMPIRICAL SPECIFICATION OF HIGH-FREQUENCY PLASMA WAVES THAT PRODUCE LOCAL ACCELERATION AND LOSS. GLOBAL EVOLUTION OF RADIATION BELT INTENSITIES IS CALCULATED WITH A TEST-PARTICLE APPROACHED WITH TIME-DEPENDENT INITIAL CONDITIONS SPECIFIED BY AN EMPIRICAL MODEL BASED ON A COMBINATION OF STATISTICS AND NEAR-REALTIME SPACECRAFT MEASUREMENT. SUCH GLOBAL DATA-DRIVEN SPECIFICATION OF RADIATION BELT INTENSITIES OVER THE FULL RAGE OF SPATIOTEMPORAL SCALES IS TIMELY AND POSSIBLE DUE TO NEW UNPRECEDENTED DATASETS (VAN ALLEN PROBES AND THEMIS) RECENT PROGRESS IN MODELING CAPABILITIES AND THE GROWTH OF COMPUTATIONAL POWER.