Alternative Source of Climate Data for Mechanistic–Empirical Pavement Performance Prediction

Abstract

The AASHTO Mechanistic–Empirical Pavement Design Guide (MEPDG) and accompanying Pavement ME Design software emphasize the influence of climate on pavement performance. Several hundred weather history files from ground-based operating weather stations (OWSs) are provided with the MEPDG software. An alternate climate data source, the Modern Era Retrospective–Analysis for Research and Application (MERRA) product from the National Aeronautics and Space Administration, is evaluated here. MERRA is a global climate reanalysis procedure that combines computed model fields with ocean-, airborne-, and satellite-based observations. MERRA has the advantage of uniform worldwide spatial coverage at an approximately 0.5° by 0.67° (latitude and longitude) horizontal resolution, continuous hourly time series from 1979 to the present, and a high level of data quality control. Comprehensive statistical comparisons between MERRA climate data and those from various conventional ground-based sources are presented. Comparisons of MEPDG performance predictions with MEPDG OWS and MERRA climate data for 20 locations distributed across the contiguous United States are also summarized. The statistical and performance prediction comparisons support the conclusion that MERRA is an acceptable and advantageous source for climate data that can be used in place of conventional ground-based OWSs.