Detecting unidentified balloons and smoke plumes in train derailments

The past few weeks have seen quite a bit of unusual activity in the United States skies. Unidentified balloons are entering our airspace and dangerous smoke has been emitted in a terrible train wreck in Ohio. The National Oceanic and Atmospheric Administration (NOAA) HYSPLIT model was used to assess both. what is it anyway

Many of us in the atmospheric science community are familiar with the HYSPLIT model, but there’s no reason you should be. According to NOAA’s Air Resources Laboratory website, HYSPLIT is “a complete system for computing simple air parcel trajectories, as well as complex transport, propagation, chemical transformation, and deposition simulations.” In other words, it is a model that can be used to assess atmospheric transport and dispersal. The website further states: “HYSPLIT has also been used in a variety of simulations describing the atmospheric transport, dispersal and deposition of pollutants and hazardous materials. Wildfire smoke, fly ash, pollutants from various stationary and mobile emission sources, allergens and volcanic ash.”

The model can perform backward or forward trajectory analysis. With this ability, we can actually trace the origin of air masses or where they are going. On February 3, 2023, a massive fire was linked to a train derailment in East Palestine, Ohio. About 50 cars carrying hazardous materials like vinyl chloride derailed, according to NOAA. Weather satellite imagery below showed cloud cover and the extent of smoke associated with the fire.

The NOAA Air Resources Laboratory released this statement on its website – “The local weather agency used HYSPLIT runs to monitor the situation and the resulting rise in the vinyl chloride plume.” They also noted that the vinyl chloride poses a significant threat to human health. Understanding plume transport, or dispersal, was critical in these circumstances.

Many of us have also been able to use the HYSPLIT model to track balloons entering North American airspace over the past few weeks. Some people used the model to try to determine the origin of objects (backward trajectories), while others used forward trajectories to estimate where they might go. The tweet below from The Washington Post Capital Weather Gang is a good example.

Incidentally, HYSPLIT uses a variety of data from numerical weather models that provide our weather forecasts. Such data comes from the GFS, NAM and HRRR models. For a full listing, this link is a good resource. To me, the irony is that our weather models rely on data from balloons to diagnose the vertical state of the atmosphere. These weather balloons are launched at least twice a day with special launches during severe weather.

All the balloons in the sky are not big evil and scary.