System for assessing Aviation's Global Emissions (SAGE), Part 1: Model description and inventory results

In early 2001, the US Federal Aviation Administration embarked on a multi-year effort to develop a new computer model, the System for assessing Aviation’s Global Emissions (SAGE). Currently at Version 1.5, the basic use of the model has centered on the development of yearly global inventories of commercial aircraft fuel burn and emissions of various pollutants to serve as the basis for scenario modeling. This paper describes the algorithms and data used in the model as well as the results from initial validation assessments. SAGE results indicate that global fuel burn and nitrogen oxide (NOx) emissions decreased by over 6% from 2000 to 2001 (fuel burn and NOx), and then steadily increased to over 12% (fuel burn) and 15.5% (NOx) above 2000 levels in 2005. Comparisons to the results from previous studies have shown that SAGE tends to agree more closely with fuel burn and NOx than with CO and HC. Validation assessments have shown that SAGE can predict per flight fuel burn to within 3% on an average basis with no apparent bias, when compared to about 60,000 flight’s worth of data from a major US airline and about 20,000 flight’s worth of data from two major Japanese airlines.