Solar radiation over and under sea ice during the POLARSTERN cruise ARK-XXVI/3 (TransArc) in summer 2011

Arctic sea ice has declined and become thinner and younger (more seasonal) during the last decade. One consequence of this is that the surface energy budget of the Arctic Ocean is changing. While the role of surface albedo has been studied intensively, it is still widely unknown how much light penetrates through sea ice into the upper ocean, affecting sea-ice mass balance, ecosystems, and geochemical processes. Here we present the first large-scale under-ice light measurements, operating spectral radiometers on a remotely operated vehicle (ROV) under Arctic sea ice in summer. This data set is used to produce an Arctic-wide map of light distribution under summer sea ice. Our results show that transmittance through first-year ice (FYI, 0.11) was almost three times larger than through multi-year ice (MYI, 0.04), and that this is mostly caused by the larger melt-pond coverage of FYI (42 vs. 23%). Also energy absorption was 50% larger in FYI than in MYI. Thus, a continuation of the observed sea-ice changes will increase the amount of light penetrating into the Arctic Ocean, enhancing sea-ice melt and affecting sea-ice and upper-ocean ecosystems.

Ensayo médico-práctico sobre el tifus-icterodes, fiebre amarilla comunmente dicha, padecido en esta ciudad por los años de 1800, 804, 810 y 813 ... /

Mode of access: Internet.

Alcuin Club collections.

Mode of access: Internet.

EPA 735-F.

Description based on: 93-012 (Aug. 1993); title from cover.

Organizational and direct support maintenance manual : teleprinter TT-804/MYQ-4A, (NSN 7010-01-153-0775).

Includes index.

Semi-annual report on a space background study. Contract DA-30-069-ORD-2803. EK/ARD ED-442 [ED-575, ED-692 and ED-735] For the Army Rocket and Guided Missile Agency, U.S. Army Ordnance Missile Command, Redstone Arsenal, Alabama.

Includes bibliography.