Advancing Understanding of the Arctic Atmosphere through Process-Level Analysis and Product Development Using Oliktok Point Measurements

Principal Investigator(s):
Gijs de Boer, University of Colorado, Boulder

Collaborator(s):
Matt Shupe (University of Colorado); Allison McComiskey (University of Colorado); Amy Solomon (University of Colorado); Sergey Matrosov (University of Colorado); Christopher Williams (University of Colorado); Dave Turner (NOAA NSSL)

The last decade has seen dramatic evidence of an evolving Arctic climate in the form of changes to sea ice cover, changes to permafrost depth and extent, modification of the habitats of animals and humans, and an evolution in plant ecosystems. The extents to which these changes result from anthropogenic activities, and the potential for these changes to impact lower-latitude weather and climate have yet to be determined. To better understand these relationships, the scientific community relies on numerical models to provide projections and develop fundamental understanding of the Earth system. Such studies provide substantial insight into various topics, but require understanding of significant uncertainties. These uncertainties stem from gaps in our understanding of fundamental processes, resulting in limited representation of these processes in the numerical models used.

Here, our team will use measurements from the United States Department of Energy (US DOE) instrumentation deployed along the North Slope of Alaska to further fundamental understanding needed for reducing uncertainty in representation of the Earth’s atmosphere in numerical models. In particular, we will use measurements from the newly deployed facility at Oliktok Point, Alaska. This site, in addition to providing needed context for long-term measurements made by the US DOE at Barrow, Alaska, additionally features a restricted airspace area that can be activated to deploy novel airborne sensing systems for study of the lower atmosphere. Examples of such systems include balloon and kite systems as well as unmanned and manned aircraft. Another unique feature of the Oliktok Point facility is that it is located within the Prudhoe Bay oil fields, providing insight into the impact of energy exploration activities on local atmospheric conditions.

Topics to be studied in detail were chosen specifically to: 1) target known deficiencies in climate and weather models; 2) fully exploit the range of instrumentation deployed at Oliktok Point; and 3) take advantage of the broad knowledge within our research team. Most directly, this includes work related to understanding clouds and aerosols, which both readily impact energy transfer between the surface of the Earth and atmosphere. Below, we list specific research targets and give a brief background on each.

Transitions between clear and cloudy atmospheric states: To better understand such transitions at high latitudes our team will use US DOE measurements to evaluate relationships between cloud cover, large-scale weather patterns and the local environment. Additionally, we will work to characterize seasonal variability of moisture and energy sources necessary for cloud formation and longevity. Using observational analyses and high-resolution process-level models, we will work to understand the role of atmospheric radiation in cloud formation, partitioning of phase between liquid and frozen hydrometeors, and the role of sub-cloud turbulence in governing cloud characteristics and lifetime.

High latitude precipitation: An inability to accurately represent the shape and mass of high-latitude snowflakes and the challenges associated with separating new precipitation from blowing snow make this an extremely challenging topic. Here, we will use advanced instrumentation, including scanning radar systems, to evaluate relationships between ice crystal shape and the amount of ice mass leaving the bottom of a cloud layer. Additionally, we will evaluate relationships between various cloud properties and the amount of precipitation mass and will improve understanding of relationships between precipitation and lower-atmospheric dynamics.

Characterization of Arctic aerosol particles and the interactions between such particles and clouds: Arctic aerosol properties impact radiaive transfer along the North Slope of Alaska in both direct and indirect ways, resulting in a change to the heating or cooling of the surface. Directly, aerosol particles scatter or reflect radiation in the atmosphere. Indirectly, aerosol particles are a critical component in the formation of clouds and precipitation. Here, we target both of these influences while simultaneously learning about the aerosol particles themselves. Specifically, we will develop understanding of the seasonal cycle of aerosol particles and their radiative effects, as well as the particle characteristics important for cloud formation. Additionally, we will contrast aerosol properties observed at Oliktok Point, situated within the Prudhoe Bay oil fields with those at Barrow, which is likely to be more pristine. We will also evaluate the role of aerosols in governing precipitation and the subsequent radiative impact of such interaction.

Characterization of Arctic clouds and their climatological influence: Finally, clouds are consistently implicated as one of the largest sources of uncertainty in models. Multiple years of cloud observations at Oliktok Point will allow us to evaluate the climatological relevance of clouds here, while simultaneously evaluating representativeness of cloud properties observed at Barrow. Also, we will work to understand the influence of open ocean on cloud formation and lifetime and the implications of such relationships on cloud cover in an Arctic state with reduced sea ice cover. Finally, we will focus on the phase of cloud particles, as liquid droplets and ice crystals impact atmospheric radiation in very different ways.

While undertaking these efforts, we will provide feedback to the US DOE on the quality and utility of different Oliktok Point data streams. Additionally, we will work with the international research community to advance Oliktok Point science, while promoting and supporting use of the Oliktok Point restricted airspace for aerial measurement campaigns.