NIST’s Urban Greenhouse Gas Measurements Program and Interactions with NOAA’s Air Resources Laboratory

The HYSPLIT atmospheric dispersion modeling tool developed by the Air Resources Laboratory (ARL) of the National Oceanic and Administration (NOAA), integrated with the STILT (Stochastic Time-Inverted Lagrangian Transport) model, has become an integral part of the analyses performed in the Urban Greenhouse Gas (GHG) Measurements Testbed System of the National Institute of Standards and Technology (NIST). The Testbed System, part of NIST’s Greenhouse Gas Measurements program begun in 2010, develops and demonstrates urban GHG emission flux quantification methods. Cities, both in the U.S. and globally, are prominent emission sources that occupy roughly 3% to 5% of the land area yet are estimated to be responsible for ~50% to 65% of global GHG emissions. NIST, working with private sector, academic, and other Federal Agency partners, has established GHG surface observing networks for carbon dioxide (CO₂), methane (CH₄), and, at some sites, carbon monoxide (CO) in three U.S. urban regions, Indianapolis, Los Angeles, and the Baltimore-Washington, D.C. region. Spatially explicit emissions models are used as prior estimates in inversion analyses. These are complemented by airborne observations of CO₂, CH₄, and CO to estimate emissions at the sub-city to facility levels. HYSPLIT is an integral part of data analyses for estimating emissions locations and strengths whether data originate from surface networks or air or space borne observations. NIST is collaborating with NOAA’s ARL, Chemical Sciences Laboratory and Global Monitoring Laboratory to develop a prototype GHG monitoring and emissions modeling program as part of a government effort toward a comprehensive GHG measurement and monitoring system for the U.S. An integral part of that effort is the HYSPLIT model.