| PI | Institute/Department | |
|---|---|---|
| Saltzman, Eric |
U of California, Irvine, Department of Earth System Science
|
| Program Manager | Funding Agency | |
|---|---|---|
| Brunt, Dr. Kelly McCarrick |
National Science Foundation
|
This project will analyze molecular hydrogen (H2) in an ice core from Summit, Greenland to reconstruct atmospheric changes in H2 over the past millennium. This will be the first record of past atmospheric H2 prior to the onset of the industrial era. The results will reveal the natural variability in paleo-atmospheric H2 and how it relates to climate change. The resulting data will provide a baseline for assessing how human activities have influenced atmospheric H2 since the preindustrial era. The results of this study will inform global assessments of how the future hydrogen economy will affect atmospheric composition and climate. The project will provide training for a postdoctoral scholar and undergraduate students.
The research involves drilling a new ice core at Summit, extracting air from the samples in the field, with subsequent analysis for H2, Ne, and CH4. Paleo-atmospheric levels of H2 will be inferred from the observed H2/Ne ratio to account for pore close-off fractionation during firn air entrapment and possible gas loss during drilling/sampling. This study will generate the first millennial scale atmospheric history of H2 and examine centennial scale variability associated with the Medieval Climate Anomaly and Little Ice Age. Climate-related variability in H2 is expected because the major loss mechanism is microbial uptake in soil, a process that is highly sensitive to hydrological conditions. The Summit paleo-atmospheric H2 record will therefore provide new constraints on our understanding of the global biogeochemical cycling of H2 and an important test for global models used to assess the climate sensitivity of future H2 emissions.
Molecular hydrogen is the third most abundant trace gas in the atmosphere, with a mean level of roughly 500 ppb and an atmospheric lifetime of about two years. As the “hydrogen economy” becomes a reality, atmospheric H2 levels are likely to rise substantially due to fuel leakage with both positive and negative consequences for atmospheric chemistry and climate. Although the atmospheric chemistry of H2 is relatively well understood, the biogeochemistry of H2 is not. For example, soil uptake is the major loss of atmospheric H2 and the rate of loss is sensitive to climatic and hydrological conditions. Uncertainty regarding the climate sensitivity of the soil sink is one of the factors limiting our ability to project future changes in atmospheric H2 levels. Reconstructing the long-term atmospheric history of H2 will reveal both natural variability and human influence on the atmospheric H2 budget. Firn air studies have yielded an atmospheric history for the past century and indicate that the ice archive should contain a record of paleoatmospheric H2. The ice core measurements will allow researchers to reconstruct the global budget for the past millennium and will inform global assessments of the atmospheric consequences of projected utilization of H2 as an energy source.
In June and July 2024, a field team of five participants (two researchers and three IDP drillers) will travel to Summit Station. The team will work in an on-station location and will drill an ice core and recover it to the surface. At a tent-based workspace, the team will then extract and capture gasses from a portion of the ice core for later analysis at the home institution. The remainder of the core will be stored at the drill site in a snow trench with a roof, end-wall and personnel door. At the end of the project, the ice core will be shipped from Summit Station through Kangerlussauq to New York via Air National Guard cold deck flight. The core will then be transported via freezer truck to the National Science Foundation Ice Core Facility.
Battelle ARO will provide Air National Guard coordination for passengers and cargo (including cold deck), ice core transport, Summit Station user days, lodging, generators and fuel, communications and safety gear, Battelle ARO science technician and field coordinator support, construction support (snow trench) of the snow trench, drilling fluids, and coordination for ice core boxes from the NSF inventory. IDP will provide the coring drill and 3 drillers. The PIs will organize and pay for all other logistics and support through the grant.
| Season | Field Site | Date In | Date Out | #People |
|---|---|---|---|---|
|
2024
|
Greenland - Summit
|
|
|
5
|