ESA-CCI_Phase2_Standardized_Manual_Visual_Ship-Based_SeaIceObservations_v01

doi:10.26050/WDCC/ESACCIPSMVSBSIO

Kern, Stefan

ExperimentDOI
Aurora AustralisCCGS Louis St. LaurentCCGS Sir Wilfried LaurierIcebreaker 50 Let PobedyIcebreaker OdenRRS James Clark RossRV LanceRV Laurence M. GouldRV Nathaniel B. PalmerRV Polarstern DBLKRV Sikuliaqsea iceshipUSCGC HealyUSCGC PolarSea
Summary
Polar regions are data sparse regions. Research ships operating in polar regions often record sea-ice conditions during their transects through ice infested waters. Such observations of the sea-ice conditions are often the only information that can be provided in addition to satellite-based estimates of the sea-ice conditions, such as sea-ice concentration or sea-ice thickness.

Such observations have been carried out and gathered using two protocols. For the Antarctic, this is the so-called ASPeCt protocol [Worby and Allison, 1999; Worby and Dirita, 1999; Worby et al., 2008]. For the Arctic, this is the so-called ASSIST/IceWatch protocol [Hutchings et al., 2018]. The latter builds on the ASPeCt protocol, incorporating surface melt conditions being more ubiquitous in the Arctic.
Ship-based observations of the sea-ice conditions are conducted manually, visually, i.e. by eye, regularly every hour taking into account an area around the ship of about one kilometer radius. Note that this area distorts to an elliptically shaped area as a function of observers' experience, ships' cruising speed and ice and visibility conditions.

Each observation comprises the total sea-ice concentration, and the concentration, level ice thickness, level ice snow depth, fraction and height of ridges, ice type, snow type, and floe size for the up to three thickest ice types. For the Arctic, melt-pond fraction and stage-of-melt are also part of the observables. In addition to the ships' position often auxiliary parameters such as visibility, wind speed and direction, or air and water temperature are recorded.

For development and evaluation of satellite-based sea-ice products, such ship-based observations are of great value. Because of this, within the ESA-CCI sea-ice ECV project (ESA-SICCI), phase 2, a standardized data set of such ship-based observations was generated for both polar regions. It comprises data from June 2002 through December 2015. This time period is motivated by the purpose to evaluate sea-ice concentration data retrieved from AMSR-E and AMSR2 brightness temperature measurements which, at the time the project was initiated, were planned to be retrieved until the end of 2015.

The data set incorporates observational data from various collections, e.g. a part of the original ASPeCt collection [Worby et al., 2008], which ended in May 2005. More information about all data sources is given below.

All data have been manually standardized to the same format (i.e., number of decimals, unit), using the same value to describe missing data, using the same temporal ordering, and filling gaps with the respective missing-data value. Double data entries have been removed. The data set is split into two ascii text files, one for the Arctic, one for the Antarctic. It has been successfully used to evaluate sea-ice concentration and thickness products of the ESA-SICCI phase 2 project.
Newer Version(s)
doi:10.26050/WDCC/ESACCIPSMVSBSIOV2
Project
ESA-SICCI_SHIPBASED_SEAICEOBS (ESA-CCI sea-ice-ecv project phase 2 bi-polar standardized manual visual ship-based sea-ice observations)
Contact
Dr. Stefan Kern (
 stefan.kern@nulluni-hamburg.de
)
Spatial Coverage
Longitude 0 to 360 Latitude -90 to 90 Altitude: 0 m
Temporal Coverage
2002-05-08 to 2016-02-08 (calendrical)
Use constraints
Creative Commons Attribution 4.0 International (CC BY 4.0) (https://creativecommons.org/licenses/by/4.0/)
Data Catalog
World Data Center for Climate
Size
422.00 KiB (432133 Byte)
Format
GZ
Status
completely archived
Creation Date
Future Review Date
2029-07-25
Find data Export dataset acronyms
Cite as
Kern, Stefan (2019). ESA-CCI_Phase2_Standardized_Manual_Visual_Ship-Based_SeaIceObservations_v01. World Data Center for Climate (WDCC) at DKRZ. https://doi.org/10.26050/WDCC/ESACCIPSMVSBSIO

BibTeX RIS
Description
Manual visual ship-based observations are often the only data source for sea-ice information in an otherwise data sparse region.
The data offered here have been quality checked and standardized. Standardized means that the observations of different ship cruises are combined such that observations of the same parameter occur in the same column. Missing columns are filled. The values used as missing value vary from parameter to parameter, depending on whether it is a floating point or integer variable and depending on whether the variable can have negative values.

Observations are usually conducted by voluntary observers with varying skills / expertise. This limits the accuracy of the observations.

Of the data included the total sea-ice concentration, given in tenth, can be regarded as the most accurate parameter; its accuracy is 5 to 10%. Accuracy is worst in the inter-mediate sea-ice concentration range from ~30% through ~70%. Partial concentrations of ice types of different thickness are possibly less accurate - especially when fractions of quite similar ice types such as thin first-year ice and medium-thick first-year ice are reported.
Next accurate are observations of sea-ice thickness and snow depth (see below though). Accuracies of the observations of other fractions, such as melt-pond fraction or fraction of ridged ice are ~10%. Ridge height observations are possibly the most difficult to evaluate and have a rather unknown accuracy.

Note that most ships tend to follow easy-to-navigate sea-ice conditions. Because of this sea-ice concentrations might be biased low during summer; the same applies all-year round for sea-ice thickness, snow depth, fraction of ridged ice and possibly also ridge height (see Worby et al., J. Geophys. Res., 113, C06S91, 2008).
I'd recommend to consider the quality of this data set as Level 2b (Geophysical Variable - basic quality control).
Description
Temporal completeness:
The data set contains ship-based observations of the years 2002 through 2015. These observations are carried out along ship trajectories. Observations are only available for the time the ship(s) operated in or near the sea-ice cover. Longer periods outside the sea-ice cover might result in a data gap.
The temporal resolution is supposed to be hourly. However, the temporal resolution varies depending on the cruise. Data gaps occur during night and/or periods with zero visibility.
Observations are chronologically order for each cruise separately. They are not chronologically order and merged in case that two ships report observations at the same date and time. In this latter case the data set contains the two overlapping time series separately.

It is planned to update the data set with more recent observations starting January 2016.

Spatial completeness:
Several factors, as are detailed below, influence the spatial coverage:
i) Observations are carried out only along ship trajectories and only at certain time intervals (usually hourly). Hence data are discontinuous along the ships' track and reflect the ice-conditions of an elliptically shaped area of 2 km width (1 km on each side of the ship) of unknown length; the length depends on the skills of the observer, the ships' speed, and the ice conditions
ii) Limited day light and visibility result in data gaps.
Description
Summary:
Findable: 6 of 7 level;
Accessible: 2 of 3 level;
Interoperable: 3 of 4 level;
Reusable: 5 of 10 level
Method
F-UJI online v2.2.1 automated
Method Description
Checks performed by WDCC. Metrics documentation: https://doi.org/10.5281/zenodo.4081213 Metric Version: metrics_v0.5
Method Url
https://www.f-uji.net
Result Date
2022-12-06
Result Date
2019-10-29
Description
1. Number of data sets is correct and > 0: passed;
2. Size of every data set is > 0: passed;
3. The data sets and corresponding metadata are accessible: passed;
4. The data sizes are controlled and correct: passed;
5. The temporal coverage description (metadata) is consistent to the data: passed;
6. The format is correct: passed;
7. Variable description and data are consistent: passed
Method
WDCC-TQA checklist
Method Description
Checks performed by WDCC. The list of TQA metrics are documented in the 'WDCC User Guide for Data Publication' Chapter 8.1.1
Method Url
https://www.wdc-climate.de/docs/WDCC_User_Guide_Data_v1.pdf
Result Date
2019-10-29
Contact typePersonORCIDOrganization
Contact
Dr. Stefan Kern
-
Center for Earth System Research and Sustainability, University of Hamburg
Author
Dr. Stefan Kern
-
Center for Earth System Research and Sustainability, University of Hamburg
Investigator
Dr. Stefan Kern
-
Center for Earth System Research and Sustainability, University of Hamburg
Metadata
Dr. Stefan Kern
-
Center for Earth System Research and Sustainability, University of Hamburg

Is previous version of

[1] DOI Kern, Stefan. (2020). ESA-CCI_Phase2_Standardized_Manual_Visual_Ship-Based_SeaIceObservations_v02. doi:10.26050/WDCC/ESACCIPSMVSBSIOV2

Is documented by

[1] Worby, A. P.; Allison, I. (1999). A technique for making ship-based observations of Antarctic sea ice thickness and characteristics: Part I. Observational technique and results, Research Report 14, pp. 1 – 23. https://www.researchgate.net/publication/292603529_A_technique_for_making_ship-based_observations_of_Antarctic_sea_ice_thickness_and_characteristics_Part_I_Observational_techniques_and_results
[2] Worby, A. P.; Dirita, V. (1999). A technique for making ship-based observations of Antarctic sea ice thickness and characteristics: Part II. User operating manual, Research Report 14, pp. 23 – 63. https://www.researchgate.net/publication/292603529_A_technique_for_making_ship-based_observations_of_Antarctic_sea_ice_thickness_and_characteristics_Part_I_Observational_techniques_and_results
[3] Hutchings, J.; Delamere, J.; Heil, J. (2018). The Ice Watch Manual. http://icewatch.gina.alaska.edu/Ice_Watch_Manual_v4.1.pdf
[4] DOI Worby, Anthony P.; Geiger, Cathleen A.; Paget, Matthew J.; Van Woert, Michael L.; Ackley, Stephen F.; DeLiberty, Tracy L. (2008). Thickness distribution of Antarctic sea ice. doi:10.1029/2007jc004254

Attached Datasets ( 2 )

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Parent project(s)

ESA-CCI sea-ice-ecv project phase 2 bi-polar standardized manual visual ship-based sea-ice observations

[Entry acronym: ESACCIPSMVSBSIO] [Entry id: 3859062]