Voß, Daniela; Henkel, Rohan; Pieck, Daniela; John, Uwe; Zielinski, Oliver (2025): Optical water quality variables (Secchi depth and Forel-Ule color indexes) observed during RV HEINCKE cruise HE431 (HABCYST) from Bremerhaven, Germany to Bremerhaven, Germany [dataset]. PANGAEA, https://doi.org/10.1594/PANGAEA.984100
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Published: 2025-08-19 • DOI registered: 2025-09-17
Abstract:
Water clarity and color were observed during the RV HEINCKE cruise HE431 (HABCYST, 18.08.2024 - 08.09.2014, Bremerhaven, Germany - Bremerhaven, Germany) using a white Secchi disc with a diameter of 40 cm and a Forel-Ule color scale. The Secchi depth (SD) was recorded as a relative measure of water clarity at each in situ station during day time. At half SD the apparent color of the water above the submerged Secchi disc was determined using the Forel-Ule color scale. A Forel-Ule color scale is a classic tools used to differentiate the percieved color of water based on a scale from 1 (indigo blue) to 21 (cola brown). The measurements were conducted as recommend in literature (Garaba and Zielinski, 2015; Wernand, 2011; Wernand and van der Woerd, 2010).
References:
Garaba, Shungudzemwoyo Pascal; Zielinski, Oliver (2015): An assessment of water quality monitoring tools in an estuarine system. Remote Sensing Applications: Society and Environment, 2, 1-10, https://doi.org/10.1016/j.rsase.2015.09.001
Wernand, Marcel Robert (2011): Poseidon's paintbox : historical archives of ocean colour in global-change perspective [dissertation]. Utrecht University, 240, https://dspace.library.uu.nl/handle/1874/212589
Wernand, Marcel Robert; van der Woerd, Hendrik J (2010): Spectral analysis of the Forel-Ule ocean colour comparator scale. Journal of the European Optical Society-Rapid Publications, 5, 10014s, https://doi.org/10.2971/jeos.2010.10014s
Funding:
Coverage:
Median Latitude: 63.223411 * Median Longitude: 10.218968 * South-bound Latitude: 57.914000 * West-bound Longitude: 4.483200 * North-bound Latitude: 69.277000 * East-bound Longitude: 15.402800
Date/Time Start: 2014-08-23T13:59:00 * Date/Time End: 2014-09-06T06:30:00
Minimum Elevation: -1002.0 m * Maximum Elevation: -11.7 m
Event(s):
HE431/01-8 * Latitude: 69.277000 * Longitude: 15.068830 * Date/Time: 2014-08-23T13:59:00 * Elevation: -128.3 m * Location: Norwegian Sea * Campaign: HE431 * Basis: Heincke * Method/Device: Secchi disk (SD)
HE431/02-5 * Latitude: 69.083000 * Longitude: 15.264000 * Date/Time: 2014-08-23T16:57:00 * Elevation: -133.3 m * Location: Norwegian Sea * Campaign: HE431 * Basis: Heincke * Method/Device: Secchi disk (SD)
HE431/03-6 * Latitude: 68.787670 * Longitude: 15.402830 * Date/Time: 2014-08-24T04:47:00 * Elevation: -95.2 m * Location: Norwegian Sea * Campaign: HE431 * Basis: Heincke * Method/Device: Secchi disk (SD)
Comment:
Chief Scientist of RV HEINCKE cruise HE431: Dr. Uwe John, Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschun, Bremerhaven
The HAB research was conducted as part of the IOC/SCOR program on Global Ecology and Oceanography of Harmful Algal Blooms (GEOHAB) within the Core Research Project on HABs in Fjords and Coastal Embayments. The AWI contribution was provided by the HGF Program Earth and Environment under PACES Theme 2 (Coast) Workpackage 3.
Parameter(s):
| # | Name | Short Name | Unit | Principal Investigator | Method/Device | Comment |
|---|---|---|---|---|---|---|
| 1 | Event label | Event | Voß, Daniela | |||
| 2 | DATE/TIME | Date/Time | Voß, Daniela | Geocode | ||
| 3 | LATITUDE | Latitude | Voß, Daniela | Geocode | ||
| 4 | LONGITUDE | Longitude | Voß, Daniela | Geocode | ||
| 5 | Depth of Secchi Disk | z(SD) | m | Voß, Daniela | Secchi disk (SD) | |
| 6 | Forel-Ule index | FUI | # | Voß, Daniela | Forel-Ule scale |
License:
Creative Commons Attribution 4.0 International (CC-BY-4.0)
Status:
Curation Level: Enhanced curation (CurationLevelC) * Processing Level: PANGAEA data processing level 3 (ProcLevel3)
Size:
56 data points
Data
| 1 Event | 2 Date/Time | 3 Latitude | 4 Longitude | 5 z(SD) [m] | 6 FUI [#] |
|---|---|---|---|---|---|
| HE431/01-8 | 2014-08-23T13:59 | 69.2770 | 15.0688 | 8.5 | 4.0 |
| HE431/02-5 | 2014-08-23T16:57 | 69.0830 | 15.2640 | 13.0 | 5.0 |
| HE431/03-6 | 2014-08-24T04:47 | 68.7877 | 15.4028 | 12.0 | 7.0 |
| HE431/04-4 | 2014-08-24T08:51 | 68.4743 | 14.9153 | 10.0 | 5.5 |
| HE431/06-5 | 2014-08-24T17:06 | 68.5490 | 14.4473 | 11.0 | 6.0 |
| HE431/07-3 | 2014-08-25T06:53 | 68.7155 | 15.0795 | 13.5 | 7.0 |
| HE431/08-5 | 2014-08-25T11:00 | 68.6765 | 14.9353 | 11.0 | 7.0 |
| HE431/09-5 | 2014-08-25T14:50 | 68.6165 | 14.6768 | 11.0 | 7.0 |
| HE431/10-3 | 2014-08-26T06:16 | 66.8468 | 13.0220 | 10.5 | 5.5 |
| HE431/11-4 | 2014-08-26T10:25 | 66.5480 | 12.6800 | 11.0 | 6.0 |
| HE431/12-3 | 2014-08-26T14:13 | 66.1665 | 12.2658 | 10.0 | 7.0 |
| HE431/13-5 | 2014-08-28T07:09 | 61.9698 | 4.6577 | 12.0 | 6.0 |
| HE431/14-5 | 2014-08-28T11:10 | 61.9248 | 5.4180 | 10.0 | 7.0 |
| HE431/15-5 | 2014-08-28T14:36 | 61.8647 | 5.7843 | 10.0 | 7.0 |
| HE431/16-5 | 2014-08-29T07:00 | 61.8648 | 6.7942 | 2.0 | 12.0 |
| HE431/17-5 | 2014-08-29T10:56 | 61.8520 | 6.2732 | 7.0 | 12.0 |
| HE431/18-5 | 2014-08-30T04:50 | 60.9010 | 4.4832 | 10.0 | 6.0 |
| HE431/21-5 | 2014-08-31T05:11 | 61.1498 | 7.3167 | 6.0 | 7.0 |
| HE431/22-4 | 2014-08-31T11:11 | 61.1678 | 6.7390 | 9.0 | 6.5 |
| HE431/23-5 | 2014-09-02T13:38 | 59.4212 | 5.0640 | 8.0 | 6.0 |
| HE431/24-5 | 2014-09-03T06:56 | 59.0865 | 5.1632 | 11.0 | 7.0 |
| HE431/25-4 | 2014-09-03T11:30 | 59.3342 | 5.9232 | 5.5 | 8.0 |
| HE431/26-9 | 2014-09-03T16:05 | 59.4768 | 6.1492 | 9.0 | 9.0 |
| HE431/27-4 | 2014-09-05T04:20 | 57.9140 | 11.5168 | 6.0 | 8.0 |
| HE431/28-5 | 2014-09-05T08:02 | 57.9383 | 11.6963 | 3.0 | 12.0 |
| HE431/29-3 | 2014-09-05T10:58 | 58.0835 | 11.7838 | 3.0 | 13.0 |
| HE431/30-4 | 2014-09-05T14:44 | 58.2483 | 11.8400 | 4.0 | 16.0 |
| HE431/31-4 | 2014-09-06T06:30 | 58.3172 | 11.7707 | 2.0 | 19.0 |