ACINN Graduate Seminar - SS 2025

2025-04-09 at 10:00 on-line only!!

Icefield breezes in the Canadian Rocky Mountains

Jono Conway

National Institute of Water and Atmosphere (NIWA), Auckland, New Zealand

 

Atmospheric boundary layer (ABL) dynamics over glaciers mediate the response of glacier mass balance to large-scale climate forcing. Despite this, very few ABL observations are available over mountain glaciers in complex terrain. An intensive field campaign was conducted in June 2015 at the Athabasca Glacier outlet of Columbia Icefield in the Canadian Rockies. Observations of wind and temperature profiles with novel kite and radio-acoustic sounding systems showed a well-defined mesoscale circulation developed between the glacier and snow-free valley in fair weather. The typical vertical ABL structure above the glacier differed from that expected for ‘glacier winds’; strong daytime down-glacier winds extended through the lowest 200 m with no up-valley return flow aloft. This structure suggests external forcing at mesoscale scales or greater and is provisionally termed an ‘icefield breeze’. The vertical and horizontal patterns of air temperature and wind speed varied greatly between icefield breeze and more typical ‘glacier wind’ conditions. These results raise several questions, including the impact of Columbia Icefield on the ABL and melt of Athabasca Glacier.I will discuss the field campaign and the observed patterns in the context of competing boundary layer processes. I will also discuss my more recent work including seasonal snow dynamics in the Southern Alps of New Zealand and cloud effects on surface energy balance and melt dynamics across global glacier datasets.

 

 

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