Research Projects

The Office of Naval Research funded, Super Dual Auroral Radar Network (SuperDARN) group at Dartmouth College and the Air Force Research Laboratory (AFRL), seek to operate a passive radio receiver at Summit Station that listens in the high frequency (HF) radio band (between 8-18 MHz), that will receive transmissions from a scientific radar in Pykkvibaer, Iceland that is part of the SuperDARN array. SuperDARN is an international collaboration of 35 HF radars in the Northern and Southern Hemispheres continuously monitoring plasma motion in the ionized region of the Earth’s upper atmosphere, known as the ionosphere. The primary goal of a receiver at Summit is to receive the Iceland radar’s pulses and calculate their arrival angles after refracting off of the ionosphere. This will permit better understanding of the path by which the radar pulses travel, which will inform continuing studies of HF propagation characteristics at auroral latitudes in terms of local irregularity formation (e.g. by auroral ionization) and horizontal density gradients associated with space weather effects.

This is a project that is jointly funded by the National Science Foundation’s Directorate of Geosciences (NSF/GEO) and the National Environment Research Council (UKRI/NERC) of the United Kingdom (UK) via the NSF/GEO-NERC Lead Agency Agreement. This Agreement allows a single joint US/UK proposal to be submitted and peer-reviewed by the Agency whose investigator has the largest proportion of the budget. Upon successful joint determination of an award, each Agency funds the proportion of the budget and the investigators associated with its own proposals and component of the work. 

This research project continues an 11-year field experiment called the Integrated Characterization of Energy, Clouds, Atmospheric state, and Precipitation at Summit (ICECAPS) and adds measurements along Lagrangian transects (ICECAPS-MELT). The project is an international collaboration that has been operating ground-based instruments at Summit Station in Greenland since 2010, taking observations of the atmosphere to advance understanding of cloud properties, radiation and surface energy, and precipitation processes over the Greenland Ice Sheet. It is an important time to make these observations because Greenland is undergoing changes due to rapid shifts in Arctic climate. The current project continues the observations made at Summit Station and expands measurements along transects to another important region of Greenland called the percolation zone. In this zone, melt water is generated at the surface, where it can percolate down into the snow and then refreeze. This creates ice layers that can cause additional melt water to move horizontally rather than vertically. It is important to understand these processes because melting of the Greenland Ice Sheet is a significant contributor to global sea level, which is predicted to impact humans significantly over the next century. 

This new ICECAPS-MELT project complements the ICECAPS Summit observatory by building a new mobile observatory for measuring parameters of the surface mass and energy budgets of the Greenland Ice Sheet. This observatory uses a novel approach for unattended, autonomous operation by supporting instruments that require moderate power and internet bandwidth yet are quite like those operated at Summit Station. The new observatory measures surface mass and energy budget parameters, including precipitation, cloud properties, radiative and turbulent fluxes, near-surface meteorology, and subsurface temperatures and structure. To do this, the ICECAPS-MELT team deploys a precipitation radar, a cloud lidar, a microwave radiometer, a ground-penetrating radar, and an automated surface flux station, which consume approximately 500 W of power under normal conditions. The project will lead to new insights into how parameters of the surface mass and energy budgets co-vary in space and time between this new observatory and the ongoing measurements at Summit. Trajectory analyses track the changes in air parcels as they ascend the Greenland Ice Sheet and pass over the two observational sites. The mobile observatory will be deployed in successive summers at Summit Station in the dry-snow zone and at the DYE-2 station in the percolation zone. If this project is successful, a network of these observatories will be proposed for future deployment in southwestern Greenland, which will provide new insights into how atmospheric properties and processes are coupled both spatially and temporally to the ice sheet’s surface and subsurface conditions over Greenland.

RNO-G is a research project that looks for radio signals created by neutrinos when they interact with polar ice. It is the first ultra-high energy neutrino observatory that can observe the Northern sky. This grant will allow the project to expand by adding new modular stations, with the aim of doubling its current level of sensitivity to these particles. The funding will support the building of antennas and systems to collect data. To set up each new station, researchers will drill three deep holes and install equipment that can work on its own. Enhancements to the experiment will ensure it can achieve its intended sensitivity and function for ten years after the array is finished. During this time, it will gather reliable data that will be shared with the wider community studying multimessenger astrophysics. 

Neutrinos can probe extreme conditions in astrophysical objects throughout the universe. This award will expand the currently operating Radio Neutrino Observatory in Greenland (RNO-G) which can observe neutrinos in a new energy scale. When combined with observations from other messengers like photons, cosmic rays, and gravitational waves, observations of neutrinos made with RNO-G can further advance our understanding of the most powerful cosmic ray accelerators and explosive events in the universe. 

This award will introduce the general public and students to particle astrophysics through workshops, research opportunities, and outreach events and provide infrastructure and engineering opportunities in Greenland.

This NASA award supports the continuation and expansion of long-term measurements of the Arctic atmosphere, snow, and other Earth system components at the Summit, Greenland, Environmental Observatory (GEOSummit). The original measurement program began in 2003. Year-round measurements with at least 10 years in duration are required to observe and quantify the roles of large-scale, multiyear oscillations in oceanic and atmospheric circulation (e.g., Arctic Oscillation), snow accumulation, firn densification, and ice flow effects. The "Broader Impacts" of these observations are numerous and include the potential to transform understanding of the role of natural and anthropogenic aerosols in climate forcing, to improve climate models and the prediction of future Arctic environmental change, provide ground calibration for satellite measurements of ice sheet elevation, and to enhance the interpretation of ice core records of paleo-environmental variability.

This project is a continuation of the Greenland Climate Network (GC-Net), a system of 16 AWS sites that were established in 1995 as part of a National Aeronautics and Space Administration (NASA) climate research program. The GC-Net AWS sites support climate monitoring, satellite data validation, and climate modeling of the Greenland ice sheet. Each GC-Net AWS is equipped with instruments measuring air temperature, wind speed, wind direction, humidity, pressure, surface radiation balance in visible and infrared wavelengths; sensible and latent heat fluxes; snowpack conductive heat flux, and snow accumulation rate at sufficient temporal resolution to resolve individual storms. The GC-Net AWS sites were previously maintained by Dr. Konrad Steffen at the Cooperative Institute for Research in Environmental Sciences (CIRES). Responsibility for operation and maintenance of the network was transferred to GEUS in 2021.

Researchers at NOAA's Earth System Research Lab (ESRL) Global Monitoring Division (GMD) conduct continuous measurements of atmospheric properties at Summit Station to better understand the Arctic climate system and contribute to the Earth monitoring mission of their worldwide observation network. GMD's mission it to acquire, evaluate, and make available accurate, long-term records of atmospheric gases, aerosol particles, clouds, and surface radiation in a manner that allows the causes and consequences of change to be understood. GMD's current measurements at Summit include: 1. Halocarbon and other Atmospheric Trace Gases (HATS) Flasks: weekly to biweekly collection of air samples, analyzed in the U.S. (Boulder, CO) for trace gases (50+ species measured) that are important to global halocarbon chemistry, such as ozone-depleting CFCs, oxidation studies, and stratospheric ozone. These measurements have been ongoing since 2004. 2. Global Greenhouse Gas Reference Network (GGGRN) Flasks: weekly collection of air samples, analyzed in the U.S. (Boulder, CO) for gases (30+ species measured) relevant to the global carbon cycle, including CO2 and methane. This sampling was first performed during several winters in the period 1997-2002 and has been performed year-round since 2003. 3. In-situ Aerosol Sampling: observations of aerosol optical properties to determine aerosol radiative effects. These measurements were initiated in 2003, with the instrument suite upgraded in 2009 and 2017. 4. Surface Ozone: observations of tropospheric ozone concentration. These measurements were taken from 2000 to 2002, and then from 2003 onward. 5. Surface Meteorology: observations of surface meteorological properties to support science, flight operations, and general station activities. These measurements have been ongoing since summer 2005.

Since their invention four hundred years ago, optical telescopes have been the primary tools used in astronomy. Over the past 25 years, scientists have started to focus more on subatomic particles, along with visible light, that come from cosmic sources. Previous experiments have shown that exploring new aspects of the universe can lead to unexpected discoveries of astronomical objects. One particularly fascinating subatomic particle is the neutrino. Neutrinos can arrive on Earth from sources that are too far away to be seen with regular telescopes. As a result, several neutrino telescopes have recently been set up in remote areas around the world, and researchers are currently developing their scientific capabilities. This approach is similar to what Galileo did when he built his telescope; shortly after it was invented, he made the remarkable discovery in 1610 of the four moons orbiting Jupiter, rather than Earth. By improving the images captured by neutrino telescopes, we may uncover equally exciting and transformative cosmic sources that could reshape our understanding of the universe.

Over the past three decades, our research group firstly demonstrated the feasibility of detecting Ultra-High Energy Neutrinos (UHEN) via in-ice radio-frequency (RF) methods, the characterization of the RF properties of polar ice has been since then an ongoing effort. Foundational measurements of the RF attenuation length and the depth-dependent refractive index (n(z)) has confirmed the suitability of cold polar ice as both a neutrino target and as an effective RF transmission medium. However, subsequent studies of RF propagation along both vertical and horizontal paths revealed unexpected ±6 dB variations in signal strength and even detected signals in configurations for which propagation should have been forbidden. Additional complexities emerged from 2018 deep pulsing experiments conducted from the SPICE borehole at the South Pole to the ARA radio receiver array, which revealed puzzling differences in amplitude and frequency content between direct (D) and refracted (R) signal paths. Aggregated calibration data highlight persistent discrepancies between theoretical models and observed behavior, particularly for receivers located in the upper 100 meters of the ice sheetknown as the firnwhere density gradients are most pronounced. This region, while ideal for deploying radio receivers using existing drilling technology, presents significant modeling challenges. Moreover, to enable multi-messenger astrophysics, it is essential to accurately reconstruct the incoming neutrino’s direction to correlate it with known astrophysical sources. While a confirmed UHEN detection may be within reach by the end of the decade, our current understanding of RF signal propagation in ice remains insufficient for precise neutrino astronomy. The discoveries of new sources will be enabled by an extended, targeted calibration campaign of the telescopes to be conducted on-site in Greenland, and off-site in our domestic laboratories.