Mission: Denman 02
Priority: Medium
 
This mission is designed to survey the centerlines of the Denman and Scott Glaciers from the edge of the Shackleton Ice Shelf to points above their fastest-flowing regions.
 
A mildly conflicting forecast for the Denman Glacier region but presently clear skies led us to select this mission, focusing on the higher priority Denman Glacier flowline and saving the Scott Glacier flowline for a future mopup mission. The Denman Glacier area was clear this morning in both forecast models and imagery, but two models (ECMWF and  WRF) disagreed with a third (GFS) about the timing of worsening cloud cover as the day progressed. GFS indicated that the clouds would move in early, with the other two models predicting the clouds to move in after we departed the area. Chalk up a victory up for the American model (GFS), because we encountered thick overcast near Denman Glacier's grounding line as we began our ascent of the glacier. Fortunately the cloud bases were fairly high at around 10,000 ft and we were able to complete the Denman run entirely, though in poor lighting conditions and, at times, poor surface visibility, with some turbulence at the upstream end of the flowline. All instruments performed well, 100% successful data collection minus bad MCoRDS channel, which detected significant ice-thickness variability along-flow. As expected based on prior far-westerly flights, we could not attempt the Scott Glacier centerline due to fuel concerns. We performed a ramp pass at 1200 ft AGL on arrival at Hobart.
 
Attached images:

1. Map of today’s mission (John Sonntag / NASA)
2. Ice-covered Mill Island, bookending the eastern end of the Shackleton Ice Shelf.  The dark area behind the circular island is known as the Highjump Archipelago, named for the massive US Navy Antarctic mapping effort undertaken in the late 1940s (John Sonntag / NASA)
3. The Obruchev Hills under thick overcast, situated between the grounding lines of Denman and Scott Glaciers (John Sonntag / NASA)