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.

(Table 1) Calculated sea surface temperature of sediment core RC11-210

Proxy indicators of sea surface temperature and equatorial divergence based on radiolarian assemblage data, and of trade wind intensity based on eolian grain size data show similar aspects of variability during the late Pleistocene: All indicators fluctuate at higher frequencies than the 100,000-year glacial-interglacial cycle, display reduced amplitude variations since 300,000 years ago, exhibit a change in the record character at about 300,000 years ago (the mid-Brunhes climatic event), and have higher amplitude variations in sediments 300,000-850,000 years old. Time series analyses were conducted to determine the spectral character of each record (delta18O of planktonic foraminifer, sea surface temperature values, equatorial divergence indicators, and wind intensity indicators) and to quantify interrecord coherence and phase relationships. The record was divided at the 300,000-year clear change in climatic variability (nonstationarity). The delta18O-based time scale is better lower in the core so our spectral analyses concentrated on the interval from 402,000-774,000 years. The delta18O spectra show 100,000- and 41,000-year power in the younger portion, 0-300,000 years, and 100,000-, 41,000- and 23,000-year power in the older interval, all highly coherent and in phase with the SPECMAP average stacked isotope record. Unlike the isotope record the dominant period in both the eolian grain size and equatorial divergence indicators is 31,000 years. This period is also important in the sea surface temperature signal where the dominant spectral peak is 100,000 years. The 31,000-year spectral component is coherent and in phase between the eolian and divergence records, confirming the link between atmospheric and ocean surface circulation for the first time in the paleoclimate record. Since the 31,000-year power appears in independent data sets within this core and also appears in other equatorial records [J. Imbrie personal communication, 1987], we assume it to be real and representative of both a nonlinear response to orbital forcing, possibly a combination of orbital tilt and eccentricity, and some resonance phenomenon required to amplify the response at this period so that it appears as a dominant frequency component. The mid-Brunhes climatic event is an important aspect of these records, but its cause remains unknown.

Publications of the National research council of Canada, 1918-1938 (N.R.C. nos. 1-773)

"Supplementary list", N.R.C. nos. 774-815 (6 p. 21 cm.) inserted at end. Mimeographed.

Droit civil expliqué : Du contrat de mariage et des droits respectifs des époux ou commentaire du titre V du livre III du Code civil /

En port.: Ouvrage qui commence la seconde série des oeuvres de l'auteur.

De la sterilité de l'homme et de la femme et des moyens d'y remédier /

Mode of access: Internet.

Compendio de la historia Universal /

Mode of access: Internet.

Reuerendi Patris Fratris Didaci Stellae ... In sacrosanctum Iesu Christi Domini nostri Euangelium secundum Lucam enarrationum : tomus primus [-secundus]

Mode of access: Internet.

Obras del V.P. ... Fr. Luis de Granada, del Orden de Santo Domingo.

Mode of access: Internet.

Florae siculae synopsis, exhibens plantas vasculares in Sicilia insulisque adjacentibus huc usque detectas secundum systema Linneanum dispositas,

"Conspectus generum et summa specierum Florae siculae secundum ordines naturales nec non index locupletissimus genera aspecies varietates et synonima omnia ejusdem florae complectens. Curis M. A. Ziccardi ...": v. 2, p. [669]-774.