This project will continue the development of realistic models of the Earth's magnetic field in the magnetosphere. In particular, this effort will be directed at improvements to the inner magnetosphere during magnetic storms. A new index will also be developed as a mechanism for parameterizing the state of the magnetic field during magnetic storms. The data for generating the improved models will come from the existing multi-spacecraft database available from the National Space Science Data Center (NSSDC). The resulting models will be made publicly available through the NSSDC.