Wiegmann, Sonja; Liu, Yangyang; Bracher, Astrid (2019): Spectrophotometric measurements of absorption coefficients by total particles, phytoplankton and non-algal particles during POLARSTERN cruise PS93.2 [dataset publication series]. PANGAEA, https://doi.org/10.1594/PANGAEA.907605, Supplement to: Liu, Yangyang; Boss, Emmanuel; Chase, Alison P; Xi, Hongyan; Zhang, Xiaodong; Röttgers, Rüdiger; Pan, Yanqun; Bracher, Astrid (2019): Retrieval of phytoplankton pigments from underway spectrophotometry in the Fram Strait. Remote Sensing, 11(3), 318, https://doi.org/10.3390/rs11030318
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Abstract:
Absorption coefficients by total particles (ap), phytoplankton (aph) and non-algal particles (aNAP) were measured on water samples collected from underway AC-S flow-through system outflow and CTD. Measurements were performed using a dual-beam UV/VIS spectrophotometer as described in Liu et al. (2018) and Liu et al. (2019).
1. About sampling:
a) underway samples were collected from unfiltered AC-S outflow (depth: 11m); CTD samples with 5-6 depths were collected on upcast.
b) vacuum pressure for filtration: maximum 200 hPa
c) samples were shock frozen in liquid nitrogen and then stored in -80°C until measurement after cruise.
d) blank filters were collected by soaking them in 0.2um filtered seawater.
e) replicates were not collected.
2. About measurements:
a) Instrument: dual-beam UV/VIS Spectrophotometer (Cary 4000, Varian Inc., Palo Alto, CA, USA) equipped with a 150 mm integrating sphere (external DRA-900, Varian, Inc. and Labsphere Inc., made from Spectralon (TM)).
b) wavelength range of scan and resolution: 300-850 nm, 1 nm.
c) slit band width: 2 nm.
d) scan speed: 150 nm min−1
e) Sample filters were extracted with 95% methanol for the absorption measurement of NAP.
f) The baseline of the spectrophotometer was set with a dry piece of a blank filter. Filters were wetted with purified water and measured regularly after every fifth sample filter served as references.
3. About data analysis:
a) interpolated wavelength range and resolution: 350-750 nm, 1nm.
b) pathlength amplification factor (beta correction factor): 4.5 (Röttgers and Gehnke 2012; Röttgers et al., 2014).
c) Null-point scattering correction at 750 nm is applied.
Further details:
Liu, Yangyang; Röttgers, Rüdiger; Ramírez-Pérez, Marta; Dinter, Tilman; Steinmetz, Francois; Nöthig, Eva-Maria; Hellmann, Sebastian; Wiegmann, Sonja; Bracher, Astrid (2018): Underway spectrophotometry in the Fram Strait (European Arctic Ocean): a highly resolved chlorophyll a data source for complementing satellite ocean color. Optics Express, 26(14), A678-A696, https://doi.org/10.1364/OE.26.00A678
Röttgers, Rüdiger; Dupouy, Cécile; Taylor, Bettina B; Bracher, Astrid; Woźniak, Slawomir B (2014): Mass-specific light absorption coefficients of natural aquatic particles in the near-infrared spectral region. Limnology and Oceanography, 59(5), 1449-1460, https://doi.org/10.4319/lo.2014.59.5.1449
Röttgers, Rüdiger; Gehnke, Steffen (2012): Measurement of light absorption by aquatic particles: improvement of the quantitative filter technique by use of an integrating sphere approach. Applied Optics, 51(9), 1336, https://doi.org/10.1364/AO.51.001336
Project(s):
Funding:
German Research Foundation (DFG), grant/award no. 268020496: TRR 172: ArctiC Amplification: Climate Relevant Atmospheric and SurfaCe Processes, and Feedback Mechanisms
Coverage:
Median Latitude: 76.942649 * Median Longitude: 6.723907 * South-bound Latitude: 73.428667 * West-bound Longitude: -3.068500 * North-bound Latitude: 80.004833 * East-bound Longitude: 14.254667
Date/Time Start: 2015-07-22T22:00:00 * Date/Time End: 2015-08-12T05:08:00
License:
Creative Commons Attribution 4.0 International (CC-BY-4.0)
Size:
3 datasets
Download Data
Datasets listed in this publication series
- Wiegmann, S; Liu, Y; Bracher, A (2019): Absorption coefficient spectra (median) of non-algal particles during POLARSTERN cruise PS93.2. https://doi.org/10.1594/PANGAEA.907604
- Wiegmann, S; Liu, Y; Bracher, A (2019): Absorption coefficient spectra (median) of phytoplankton during POLARSTERN cruise PS93.2. https://doi.org/10.1594/PANGAEA.907593
- Wiegmann, S; Liu, Y; Bracher, A (2019): Absorption coefficient spectra (median) of all particles during POLARSTERN cruise PS93.2. https://doi.org/10.1594/PANGAEA.907603