Campus Map

Madison Smith

Research Assistant




2000-present and while at APL-UW

Overview of the Arctic Sea State and Boundary Layer Physics Program

Thomson, J., and 32 others, including L. Rainville, and M. Smith, "Overview of the Arctic Sea State and Boundary Layer Physics Program," J. Geophys. Res., 123, 8674-8687, doi:10.1002/2018JC013766, 2018.

More Info

1 Dec 2018

A large collaborative program has studied the coupled air‐ice‐ocean‐wave processes occurring in the Arctic during the autumn ice advance. The program included a field campaign in the western Arctic during the autumn of 2015, with in situ data collection and both aerial and satellite remote sensing. Many of the analyses have focused on using and improving forecast models. Summarizing and synthesizing the results from a series of separate papers, the overall view is of an Arctic shifting to a more seasonal system. The dramatic increase in open water extent and duration in the autumn means that large surface waves and significant surface heat fluxes are now common. When refreezing finally does occur, it is a highly variable process in space and time. Wind and wave events drive episodic advances and retreats of the ice edge, with associated variations in sea ice formation types (e.g., pancakes, nilas). This variability becomes imprinted on the winter ice cover, which in turn affects the melt season the following year.

Episodic reversal of autumn ice advance caused by release of ocean heat in the Beaufort Sea

Smith, M., S. Stammerjohn, O. Persson, L. Rainville, G. Liu, W. Perrie, R. Robertson, J. Jackson, and J. Thomson, "Episodic reversal of autumn ice advance caused by release of ocean heat in the Beaufort Sea," J. Geophys. Res., 123, 3164-3185, doi:10.1002/2018JC013764, 2018.

More Info

1 May 2018

High‐resolution measurements of the air‐ice‐ocean system during an October 2015 event in the Beaufort Sea demonstrate how stored ocean heat can be released to temporarily reverse seasonal ice advance. Strong on‐ice winds over a vast fetch caused mixing and release of heat from the upper ocean. This heat was sufficient to melt large areas of thin, newly formed pancake ice; an average of 10 MJ/m2 was lost from the upper ocean in the study area, resulting in ~3–5 cm pancake sea ice melt. Heat and salt budgets create a consistent picture of the evolving air‐ice‐ocean system during this event, in both a fixed and ice‐following (Lagrangian) reference frame. The heat lost from the upper ocean is large compared with prior observations of ocean heat flux under thick, multi‐year Arctic sea ice. In contrast to prior studies, where almost all heat lost goes into ice melt, a significant portion of the ocean heat released in this event goes directly to the atmosphere, while the remainder (~30–40%) goes into melting sea ice. The magnitude of ocean mixing during this event may have been enhanced by large surface waves, reaching nearly 5 m at the peak, which are becoming increasingly common in the autumn Arctic Ocean. The wave effects are explored by comparing the air‐ice‐ocean evolution observed at short and long fetches, and a common scaling for Langmuir turbulence. After the event, the ocean mixed layer was deeper and cooler, and autumn ice formation resumed.

Observations of surface wave dispersion in the marginal ice zone

Collins, C., M. Doble, B. Lund, and M. Smith, "Observations of surface wave dispersion in the marginal ice zone," J. Geophys. Res., 123, 3336-3354, doi:10.1029/2018JC013788, 2018.

More Info

1 May 2018

This study presents the most comprehensive set of in situ and remote sensing measurements of wave number, and hence the dispersion relation, in ice to date. A number of surface‐following buoys were deployed in sea ice from the R/V Sikuliaq, which also hosted an X‐band marine radar, during the ONR Arctic Sea State field experiment. The heave‐slope‐correlation method was used to estimate the root‐mean‐square wave number from the buoys. The method was highly sensitive to noise, and extensive quality control measures were developed to isolate real signals in the estimated wave number. The buoy measurements were complemented by shipboard marine X‐band radar dispersion measurements, which are limited to lower frequencies (<0.32 Hz). Overall, deviation from the linear open water dispersion relation was not significant, and matched the open water relation nearly exactly for the range 0.10–0.30 Hz. Isolating a subset of data during the strongest wave event showed evidence of increased wave numbers at frequencies greater than 0.30 Hz. The ice conditions and deviation from linear open water dispersion were qualitatively consistent with predictions from the mass loading model. However, the dispersion curves did not exactly follow the contours of the mass loading model, suggesting either measurement error or other processes at play.

More Publications

Acoustics Air-Sea Interaction & Remote Sensing Center for Environmental & Information Systems Center for Industrial & Medical Ultrasound Electronic & Photonic Systems Ocean Engineering Ocean Physics Polar Science Center