ARL Weekly News – March 3, 2025

Recent Events

HYSPLIT update approved for operations

HYSPLIT v9 has been approved for implementation into the National Center for Environmental Protections operations.  HYSPLIT v9 provides significant enhancements, including updates to the model code, the addition of a transfer coefficient matrix (TCM) capability for volcanic ash and radiological releases, and stronger integration with global weather prediction models. Developed after the Fukushima-Daiichi Nuclear Power Station radiological release in March 2011, the TCM is a mature capability now ready for operational deployment. It computes source-receptor relationships based on time-resolved, unit source emissions simulations, allowing the TCM to be multiplied by actual emissions to determine downwind impacts. This approach enables rapid updates when new emissions estimates become available, eliminating the need to rerun transport and dispersion simulations—an essential capability for ongoing events and for incorporating improved emissions estimates. The TCM can  also be used to construct ensembles that represent uncertainty in emissions and to estimate emissions using available observations through an inversion algorithm. The radiological release upgrade which supports modeling for the Regional Specialized Meteorological Center (RSMC)  meets requests from the International Atomic Energy Agency (IAEA).  The volcanic ash upgrade will help fulfill new ICAO requirements for Volcanic Ash Advisory Centers (VAACs), improving their workflow and providing uncertainty information in aviation hazard forecasts. Enhanced coupling with the GFS and GEFS models strengthens HYSPLIT’s ability to support responses to global events and assess their impact on the United States. Stakeholders who participated in the evaluation provided favorable feedback. The Environmental Modeling Center (EMC) director approved the implementation at a meeting on Monday, February 24, followed by approval from the NCEP Director on Wednesday, February 26. Implementation is scheduled for the end of May 2025. The public notification statement is available at this link. The implementation was partially funded by the Joint Technology Transfer Initiative (JTTI) and was a collaborative effort between EMC and ARL, with contributions from Tianfeng Chai, Mark Cohen, Alice Crawford, and Sonny Zinn from ARL, Fanglin Yang of EMC, Binyu Wang, Raffaele Montuoro and Jeff McQueen (now retired) from EMC.

ARL collaboration to make Global Forecast System data available to the public

Rick Jiang and Dr. Patrick Campbell of ASMD recently collaborated with the NOAA Open Data Dissemination (NODD) Program Office to make operational NOAA Global Forecast System (GFS) netCDF Formatted Data publicly available on Amazon Web Services (AWS). This dataset, spanning from March 2021 to the present (currently ~300TB), is updated daily.

The GFS netCDF data is specifically used for NOAA-ARL products, including the NOAA-EPA Atmosphere-Chemistry Coupler (NACC) and canopy-app. It is also highly valuable to the broader air quality modeling community and supports a wide range of Earth System Modeling applications.

Patrick Keown, Program Manager for NOAA Open Data Dissemination (NODD), contributed to the effort, while Amy Biggs, Assistant Chief Data Officer for NOAA Research, coordinated the onboarding process.

For more details and data access, visit the Registry of Open Data on AWS: NOAA-OAR-ARL NACC Public Dataset

HYSPLIT helps emergency managers during a potential hazardous chemical release

A crash on I-44 in southern Missouri between two tractor-trailers closed down the interstate and raised concerns about potential chemical reactions on March 5. While no one was hurt in the accident, the concern was that the diesel fuel spilled from one of the truck payloads and chlorine tablets from the other could mix and create a hazardous chemical reaction. The Weather Forecasting Office in Springfield provided a HYPLIT run and a weather briefing to let emergency personnel know where airborne chemicals would to keep everyone safe. Fortunately, there was no chemical reaction and crews were able to clear up the accident and reopen the highway.

Publications and Presentations

Accepted for publication

Praveena Krishnan and  Tilden Meyers co-authored “Coupling Remote Sensing with a Process Model for the Simulation of Rangeland Carbon Dynamics” which has been accepted for publication in the Journal of Advances in Modeling Earth Systems.

Poster Presentation

On Monday, March 3, Nebila Lichiheb presented a poster at the 2025 ORAU annual meeting in Knoxville. Her poster summarized the ground-based data collected at the Yale Coastal Field station within the AEROMMA campaign. The title of the poster is: “Atmospheric ammonia measurements at a coastal site along the east coast of the USA.”