ALBERT

Description: River water is the main source of dissolved organic carbon (DOC) in the Arctic Ocean. DOC plays and important role in the Arctic carbon cycle and its export from land to sea is expected to increase with accelerated permafrost thaw with ongoing climate change. However, transport ways and transformation of DOC is mostly unknown. The absorption coefficient by colored dissolved organic matter (aCDOM) which can be used to estimate DOC concentration. In this study, we compiled DOC and aCDOM samples from 11 expeditions covering river, coastal and offshore waters. Water samples for DOC analysis were filtered through 0.7µm GF/F filter and acidified with 25 µL HCl suprapur (10 M) right after sampling. Samples were stored cool and dark for transport. DOC concentrations were measured using high temperature catalytic oxidation (TOC-VCPH, Shimadzu). Three measurements of each sample were averaged and after each 10 samples, a blank and a standard (Battle-02, Mauri-09 or Super-05 certified reference material from National Laboratory for Environmental Testing, Canada) were measured to sustain a quality control. Samples for aCDOM(λ) analysis were filtered through 0.22 µm Millipore GSWP filters (Gonçalves-Araujo et al., 2015, Lena 2016, Bykovksy 2017) or 0.7 µm Whatman GF/F (LD10, YS11, VB13, VB14, Lena 2014, Lena 2015) right after sampling. 100 ml filtrate was stored cool and dark in amber glass bottles until further analysis. aCDOM(λ) was measured with spectrophotometer (SPECORD 200, Analytik Jena) by measuring the absorbance (Aλ) in 1 nm intervals between 200 and 750 nm. The resulting absorbance measurements were then applied to a standard equation aCDOM (λ)=(2.303*A_λ)/L, where L is the path length (length of cuvette), to calculate the aCDOM(λ). Fresh Milli-Q water was used as reference. The cuvette length varied depending on the expected absorption in the sampled water (1 or 5 cm for river or coastal waters, 5 or 10 cm for offshore shelf waters). Resulting aCDOM spectra were corrected for baseline offsets by subtracting the absorption at 700 nm, assuming zero absorption at 700 nm.

Description: Aerial observations of light pollution can fill an important gap between ground based surveys and nighttime satellite data. Terrestrially bound surveys are labor intensive and are generally limited to a small spatial extent, and while existing satellite data cover the whole world, they are limited to coarse resolution. This paper describes the production of a high resolution (1 m) mosaic image of the city of Berlin, Germany at night. The dataset is spatially analyzed to identify themajor sources of light pollution in the city based on urban land use data. An area-independent 'brightness factor' is introduced that allows direct comparison of the light emission from differently sized land use classes, and the percentage area with values above average brightness is calculated for each class. Using this methodology, lighting associated with streets has been found to be the dominant source of zenith directed light pollution (31.6%), although other land use classes have much higher average brightness. These results are compared with other urban light pollution quantification studies. The minimum resolution required for an analysis of this type is found to be near 10 m. Future applications of high resolution datasets such as this one could include: studies of the efficacy of light pollution mitigation measures, improved light pollution simulations, economic and energy use, the relationship between artificial light and ecological parameters (e.g. circadian rhythm, fitness, mate selection, species distributions, migration barriers and seasonal behavior), or the management of nightscapes. To encourage further scientific inquiry, the mosaic data is freely available at Pangaea.

Description: Current velocity data from an equatorial mooring in the Atlantic( 0°N, 35°W ). The aim was to study the equatorial deep jets. Included is data from 4 rotor current meters (Aanderaa RCM 8). These instruments were incorporated in WHOI mooring 938 .

Description: A long-term mean flow field for the subpolar North Atlantic region with a horizontal resolution of approximately 25km is created by gridding Argo-derived velocity vectors using two different topography-following interpolation schemes. The 10-day float displacements in the typical drift depths of 1000 to 1500m represent the flow in the Labrador Sea Water density range. Both mapping algorithms separate the flow field into potential vorticity (PV) conserving, i.e., topography-following contribution and a deviating part, which we define as the eddy contribution. To verify the significance of the separation, we compare the mean flow and the eddy kinetic energy (EKE), derived from both mapping algorithms, with those obtained from multiyear mooring observations.

Description: The intraseasonal variability of the tropical eastern boundary upwelling region in the Atlantic Ocean is investigated using multi-year mooring off Angola