Cold and warm temperature advection mask for the Antarctic Circumnavigation Expedition from December 2016 – March 2017.

***** Dataset abstract *****

This dataset contains a mask for the identification of cold and warm temperature advection along the Antarctic Circumnavigation Expedition (ACE) track based on a simple method using the difference between the sea surface and air temperature. This mask is a combination of measured air temperature and sea surface temperature during ACE.

***** Data processing *****

The difference between sea surface and air temperature is used as a simple measure of cold and warm temperature advection. Warm temperature advection is defined if the temperature difference is larger than 0°C, cold temperature advection if the difference is smaller than 0°C. The time gap between two advection events of the same type has to be at least 6 hours, otherwise, the time in between these events is considered to be the same kind of advection. This is done to prevent the mask being too noisy due to short-term changes in temperature.

The cold and warm temperature advection mask is calculated using the measured air temperature (Landwehr et al., 2019; doi: 10.5281/zenodo.3379590) and sea surface temperature (Haumann et al., 2020; doi: 10.5281/zenodo.3660852) during ACE. The air and sea surface temperature time series are averaged to a 1-hourly resolution.

***** Quality checking *****

No filter has been applied. Two filters are given in the data file for land areas (filter_lsm), based on the land sea mask from the ECMWF operational analysis data, and sea ice areas (filter_sif), based on the sea ice area fraction from Haumann et al. (2020). If these filters have a value of 1, the ship track (Thomas and Pina Estany, 2019; doi: 10.5281/zenodo.3483164) was close to or within land or sea ice, respectively.

NaN values are given for time periods when either measurements of air or sea surface temperature are missing.

***** Further information for interpreting the data and using the dataset *****

Filters: 12h and 6h filters were applied to the data (makscw_all), giving two time lines with cold and warm advection events of at least 12h (makscw_12h) and 6h (maskcw_6h) in length, respectively.

Timescales: The data may be interpolated to a resolution of seconds.

Aggregation: The data may be aggregated to a resolution of 12h. An aggregation of the data can lead to the omission of short advection events on the timescale of a few hours. 

***** Dataset contents *****

- coldwarm_mask_1h.csv, data file, comma-separated values
- data_file_header.txt, metadata, text
- README.txt, metadata, text
- change_log.txt, metadata, text

***** Dataset contact *****

Iris Thurnherr, Institute for Atmospheric and Climate Science, ETH Zurich, Switzerland. ORCID: 0000-0003-3647-0373. Email: iris.thurnherr@env.ethz.ch Telephone: +41 44 632 82 66

***** Dataset license*****

This cold and warm temperature advection mask dataset from ACE is made available under the Creative Commons Attribution 4.0 International License (CC BY 4.0) whose full text can be found at https://creativecommons.org/licenses/by/4.0/

***** Dataset citation *****

Thurnherr, I., Aemisegger, F., & Wernli, H. (2020). Cold and warm temperature advection mask for the Antarctic Circumnavigation Expedition from December 2016 – March 2017. (Version 1.1) [Data set]. Zenodo. http://doi.org/10.5281/zenodo.3989318