As of Nov. 20 it was clear that US ITASE Phase 2 would not be able to
start its traverse until early December.
The causes for the delays are discussed below. From Nov. 20-Dec. 1,
the partial US ITASE crew at Taylor Dome
obtained a 100 m core and a few tens of km of deep radar profiles.
From Dec. 6-12 an additional 12 km of shallow
and deep radar profiles were obtained.
US ITASE Phase 2 began its traverse on Dec. 14, 2006. This date is
20-24 days later than planned, depending
on the expected date of departure from Taylor Dome of Nov. 20-24.
| System | Drill Type | Diameter (inches) |
|---|---|---|
| E | Eclipse | 3 |
| R | Rongbuk | 2 |
| P | PICO | 3 |
Ice Cores (Mike Waszkiewicz, Data Logging North; Paul Mayewski, Dan Dixon, Andrei Kurbatov, Gordon Hamilton, Dan Breton, U. Maine; Joe Flaherty, Lora Koenig, U. Washington). See Table 2. For locations see figs. 3, 4.
Snowpits Dan Dixon (U. Maine), Joe Flaherty (U. Washington), see Table 3.
Surface Snow Sampling (Dan Dixon, U. Maine). SS sites (13 sites, see figs 3, 4, sampled at surface, surface to 10 cm and surface to 20 cm
Deep radar sounding (BrianWelch, St. Olaf College). Improvements to the 3 MHz radar over the past few years have greatly enhanced the quality of data and our ability to collaborate with the rest of the US-ITASE team. Over 500 km of radar profiles were recorded, including the entire traverse route and multiple local along-flow profiles near the ice core sites. Ice thickness ranged from a few meters near Mt. Crean at Taylor Dome to nearly 3 km in the Byrd Glacier basin. Shallow stratigraphy was recorded to within 50 m of the ice surface allowing comparisons with Steve Arcone’s 400 MHz data, optimal positioning of the ice core sites, and analysis of near-surface voids. Some improvements are needed to increase operator safety in areas of large sastrugi.
GPS, Shallow and Crevasse Radar Sounding (Steve Arcone, CRREL, Gordon Hamilton, U. Maine). 580 km continuous.
Mass Balance (Gordon Hamilton, U. Maine). GPS sites placed at 06-01, 06-02, 06-03 (see fig, 2).
High Resolution Density (Dan Breton, U. Maine). A prototype of the Maine Automated Density Gauge Experiment (MADGE) was successfully field tested this year. The instrument provides high resolution, high accuracy and non–destructive density measurements on 2 and 3" ice cores using a small gamma–ray source, a fast nuclear counting system and an electronic caliper system for measuring core diameters. MADGE processed all 75m of 2" core drilled this season, providing density measurements with a ±0.003 g/cm3 uncertainty every 3.3 mm along each core. The density gauge data matches well with manual density measurements from snow pits and measurements on nearby 3 cores. Shallow GPR data collected at the drill sites will be matched with the MADGE density data in an effort to better understand the nature of the radar reflectors and stratigraphy observed along ITASE traverse routes.
35-GHz radar (Lora Koenig, U.Washington). Firn properties were investigated in the upper 2 meters of firn using very high frequency radar penetration depths. Known reflectors were placed in the firn and a 35-GHz FMCW radar was used to quantify how energy is lost as a function of depth in the firn and as a function of firn structure. This data will be used to further investigation of space-borne passive microwave models of temperature and accumulation.
Snowpit |
Latitude (S) |
Longitude (E) |
Depth (m) |
06-01 |
77 52°48.8” |
158 27° 29.6” |
1.1 |
06-02 |
77.78107 |
152.37047 |
1.2 |
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