Invited article: SUBGLACIOR: an optical analyzer embedded in an Antarctic ice probe for exploring the past climate

Area of Science:

• Paleoclimatology
• Atmospheric Science
• Geophysics

Background:

• Ice cores preserve ancient atmospheric composition, offering insights into past climate.
• Understanding past climate cycles requires analyzing isotopic variations and greenhouse gas concentrations.
• Current methods for analyzing deep ice cores can be time-consuming and may not provide real-time data.

Purpose of the Study:

• To develop and present the SUBGLACIOR optical spectrometer for in situ ice-core analysis.
• To enable real-time measurement of deuterium (δ(2)H) and methane (CH4) concentrations in Antarctic ice sheets.
• To assess the suitability of sites for retrieving ice cores up to 1.5 million years old.

Main Methods:

• Development of a novel optical spectrometer utilizing Optical Feedback-Cavity Enhanced Absorption Spectroscopy.
• Integration of the spectrometer into a drilling probe for direct, in situ measurements.
• Real-time, simultaneous profiling of δ(2)H and CH4 concentrations at depths down to 3500 meters.

Main Results:

• The SUBGLACIOR spectrometer achieves a noise equivalent absorption coefficient of 2.8 × 10(-10) cm(-1) Hz(-1/2).
• Detection limits of 0.2 ppbv for CH4 and a precision of 0.2‰ for δ(2)H were achieved within a 1-minute acquisition time.
• Demonstrated capability for real-time vertical profiling of key climate proxies.

Conclusions:

• SUBGLACIOR represents a significant technological advancement for ice-core research.
• The instrument facilitates rapid, in situ assessment of ice core quality and age potential.
• This technology will enhance our understanding of long-term climate variability and cycles.