High Altitude Disturbance: An Integrated Experimental and Modeling Approach to Quantifying Turbulence and Aerosols at Hypersonic Flight Height

Project Overview

This project focused on predicting and characterizing high-altitude "weather", also known as atmospheric disturbance events, found in the lower and mid-stratosphere. The causes and scales of stratospheric weather differ greatly from those found in the troposphere and stratospheric weather events are described by the aerosol and turbulence environment. With recent attention towards hypersonic vehicles, predicting these disturbance events is critical for successful high-altitude flight missions. We approached this science topic using a combination of atmospheric modeling, high-altitude plane observations, new sensor design and fabrication, and high-altitude balloon campaigns targeting an atmospheric phenomenon called gravity waves.

In situ stratospheric turbulence observations were made using a custom-made Fluctuations in the Stratosphere with Hot Wire (FiSH) sensor. Stratospheric aerosols were collected using a new sensor designed by this LDRD called the Generalized Aerosol Sampling Payload (GASP). Airbourne aerosols, as well as those deposited to the surface via rainfall, were collected in situ and brought back to Lawrence Livermore National Laboratory's (LLNL) Center for Accelerator Mass Spectrometry (CAMS) for isotope analysis, which were used as atmospheric tracers stratosphere-troposphere exchange (STE) processes. A series of field campaigns were conducted in 2020 and 2021, the last being our largest and most complex campaign called the Beryllium Isotopes for Resolving Dynamics in the Stratosphere (BIRDIES) experiment in the U.S. Central Plains. Our complimentary modeling tasks showed that the Weather Research and Forecasting (WRF) model can accurately simulate the formation of and propagation of gravity waves and their breaking into smaller scales of turbulence at least up to altitudes in the mid-stratosphere. The model GEOS-CHEM was run to predict concentrations of beryllium-10 and beryllium-7 found in the lower stratosphere. These simulations agreed well with our measurements of the cosmogenic isotopes showing promise for the model to accurately predict STE conditions, at least during our seasonal North American field campaigns. Better characterization of the high-altitude environment has broad implications beyond hypersonic flight. These include geoengineering, nuclear monitoring, extreme fire meteorology, volcanic eruptions, and climate change.

Mission Impact

The results and deliverables from this project have a wide number of benefits that support the DOE/NNSA mission. These include developing science and technology tools and capabilities to meet future national security challenges (through our advancements in WRF and development of the GASP sensor), enabling NNSA to create new ways of responding to national security challenges (including new capabilities for monitoring in the stratosphere), and addresses DOE's energy and environmental security missions (including new sensors for geoengineering and climate impacts research). We also built collaborations with the University of Maryland, Sandia National Laboratory, 99th Reconnaissance Squadron, NASA, and the UCLA (they are using our FiSH data as free-stream input into hypersonics code). This project resulted in LLNL owning two sensors to fly in the stratosphere for measuring stratospheric conditions (GASP and FiSH) and the capability to run WRF to the mid-stratosphere for climate and national security missions.

Publications, Presentations, and Patents

Beydoun, H., Caldwell P.M., Stein, E.V., Wharton, S. (2023)/ "Tracing the rain formation pathways in numerical simulations of deep convection." J Advances in Modeling Earth Systems 15: e2022MS003413. doi.org/10.1029/2022MS003413

Ehrmann, T.S., Cameron-Smith, P.J., Wharton, S. (2022)/ "A Climatology of Clear-Air Turbulence and Mountain Wave Turbulence Throughout the Stratosphere Using MERRA-2 Data." Technical Report. LLNL-TR-845959

Wharton, S., Hidy, A., Lee, J., Repasch, M. (2023)/ "Beryllium Isotopes in Rainfall for Stratospheric-Tropospheric Exchange Dynamics Experiment (BIRDIE)." Final Campaign Report for the DOE Atmospheric Radiation Measurement (ARM) User Facility. LLNL-TR-847333

Zhu, W., Skinner, S., Laurence, S.J., Wharton, S., Hidy, A.J., Ehrmann, T.S. (2023). "Stratospheric Turbulence Measurements with Payload FiSH and Meteorological Balloons." Conference Proceeding in American Institute of Aeronautics and Astronautics (AIAA) Aviation and Aeronautics Forum. https://doi.org/10.2514/6.2023-3544

T.S. Ehrmann, A. Hidy, S. Skinner, S. Laurence, S. Wharton, "Stratospheric Turbulence Associated with Deep Convection Observed Through In-Situ Measurements of Wind and Atmospheric Tracers" (Presentation, Dynamics and Chemistry of the Summer Stratosphere (DCOTSS) 2021 Science Team Meeting, 2021).

T.S. Ehrmann,  P.J. Cameron-Smith, S. Wharton,"Determining Stratospheric Turbulence Statistics from ER-2 Flight Data" (Presentation, 22nd Conference on Aviation, Range, and Aerospace Meteorology, 102nd American Meteorological Society Annual Meeting, Houston, TX, Jan 25, 2022). 

T.S. Ehrmann, P. Cameron-Smith, S. Wharton,"A Climatology of Clear-Air Turbulence and Mountain Wave Turbulence through the Stratosphere using MERRA-2 data" (Presentation, 21st Conference on Middle Atmosphere,102nd American Meteorological Society Annual Meeting, Houston, TX, Jan 25, 2022).

T,S. Ehrmann, P. Cameron-Smith, S. Wharton, "Determining Stratospheric Turbulence Statistics from ER-2 Flight Data" (Presentation, SPARC Gravity Wave Symposium, Frankfurt, Germany, 28 March-1 April 2022).

A.J. Hidy, S. Wharton, S. Skinner, T.S. Ehrmann, M. Repasch, "Obtaining Spatial Datasets of Atmospherically Produced Cosmogenic 10Be/7Be to Fingerprint Stratospheric Disturbances" (Presentation, International Conference on Methods and Applications of Radioanalytical Chemistry (MARC), Kona, HI, 3-8 April 2022).

Hidy, A.J., Repasch, M., Wharton, S, Ehrmann, T.S., Beydoun, H., P.J. Cameron-Smith, E. Oerter, A. Visser, "Searching for Signatures of Stratospheric Disturbance with Large Spatial Datasets of Meteoric 10Be/7Be" (Presentation, Session on Advances in Tracer Methods and Modeling of Hydrochronology, Hydrologic Processes, and Residence Times, American Geophysical Union Fall Meeting, Chicago, IL, 12-16 Dec 2022).

M. Repasch, A.J. Hidy, S. Wharton, P.J. Cameron-Smith, T.S. Ehrmann, H. Beydoun, "Precipitation Scavenging of Cosmogenic 10Be and 7Be: Understanding the Spatial and Temporal Dynamics of Wet Deposition" (Presentation, 37th Conference on Hydrology, 103rd American Meteorological Society Annual Meeting, Denver, CO, 8-12 January 2023).

S. Wharton, "LLNL High Altitude R&D in Support of Hypersonics" (Presentation, United States Air Force/Army Weather R&D Virtual Workshop, 24 Sept 2020).

S. Wharton, A.J. Hidy, T.S. Ehrmann, H. Beydoun, P.J. Cameron-Smith, W. Zhu, S.N Skinner, "Beryllium Isotopes for Resolving Dynamics in the Stratosphere (BIRDIES): A Balloon Campaign Targeting Deep Convection Gravity Waves" (Presentation, AGU Fall Meeting, Chicago, IL, 12-16 Dec 2022).

W. Zhu, S. Skinner, S. J. Laurence, S. Wharton, A.J. Hidy, T.S. Ehrmann, "Stratospheric Turbulence Measurements with Payload FiSH and Meteorological Balloons" (Presentation, AIAA Aviation and Aeronautics Forum, San Diego, CA, 12-16 June 2023). 

Generalized Aerosol Sampling Payload (GASP). Skinner, S., Hidy, A.J., Zhu, W., Ehrmann, T.S., Wharton, S., Sanchez A.L., Storch, S.M., Vigil, C.J., Cameron-Smith, P.J. Patent in progress.