Remote sensing of wildfires from the MISR instrument on the polar-orbiting NASA Terra satellite using the MINX software tool

Knowledge of the height at which smoke from wildfires is injected into the atmosphere is critical for accurately modeling its transport. Smoke that rises above the boundary layer can be carried long distances and have significant impact on visibility, air quality, and human health far from the fire source. Injection heights determined under a wide range of conditions are required for improving smoke injection parameterizations in chemical transport and climate models. However, determining smoke injection heights for more than a handful of cases can only be reasonably accomplished from a satellite platform. Such measurements are challenging because detailed knowledge of the atmospheric temperature and moisture structure is often lacking, limiting the utility of thermal infrared techniques, and wildfires often occur in complex terrain, requiring the retrievals to have relatively high spatial resolution.

Spaceborne lidar systems are appealing because they provide extremely high vertical resolution, but are limited to an extremely narrow swath. An alternative method is passive stereoscopic imagery, such as that provided by the Multi-angle Imaging SpectroRadiometer (MISR) instrument, which has been operational on the polar-orbiting NASA Terra satellite since early 2000. MISR makes observations from nine cameras at 275 m spatial resolution with a 400 km swath, providing both resolution and context for wildfires. The MISR INteractive eXplorer (MINX) software tool has been developed and refined over the past few years to provide information on the heights of smoke and other types of plumes with a vertical accuracy of ~200 m, including retrievals of the wind speed at the plume top. This information can be used to evaluate model performance in post-operational assessments and improve smoke injection parameterizations.

We will describe the MINX software tool, including a number of improvements made in the past year. Large-scale studies making use of a plume height database generated using MINX will be discussed, and case studies will be shown of the relationship between meteorological conditions and wildfire smoke injection height.