Coastal polynyas play an important role in sea ice production, dense water formation, and ocean-atmosphere interactions. To accurately estimate the amount of sea ice produced in a polynya, it is crucial to know the sea ice transport rate away from shore or, equivalently, the speed of the polynya boundary. Yet, despite the high importance of this quantity, there is a scarcity of observational data on it, especially regarding the short-term, detailed dynamics. This manually prepared dataset describes the dynamical evolution of the Terra Nova Bay Polynya (Antarctica), based on MODIS satellite data collected between 2012 and 2024. For each of 52 polynya events, the dataset consists of series of polynya boundary lines that indicate the sea ice movement and provide estimates of the velocities at which ice was displaced offshore during each polynya event. The accuracy of the polynya boundary line location is estimated to be ± 1 km. Additionally, the dataset includes information on wind speed, wind direction, atmospheric pressure, and other meteorological parameters given as mean, minimal, and maximal values for the time intervals between consecutive satellite images. The raw meteorological data were obtained from the automatic weather station Manuela, located on the Inexpressible Island, and operated by the University of Wisconsin-Madison Antarctic Meteorological Research Center. This dataset stands out due to its unprecedented high temporal resolution of several images per day. This feature is essential to accurately describe polynya dynamics as they can open and close even within 24 h.

The data are organized as follows:
Each folder named "YYYY-mm-DD.zip" contains all data related to a given event.Within each ZIP archive, you will find 3 subfolders and file with meteorological statistics.SUBFOLDERS:1. 'shapefiles': One or more .shp files containing georeferenced series of polynya boundary lines. Each line has a unique ID corresponding to its sequence in the dataset, i.e., to consecutive satellite images. The numbering is not always continuous, as some satellite scenes were excluded (e.g., due to clouds or poor image quality), resulting in missing ID values in the sequence. For a given event, there may be one shapefile or several, depending on the number of individual polynya boundaries detected.2. 'date_overviewtif': set of .tiff files that illustrate the satellite image, cut to Terra Nova Bay region.3. 'displacement': Four .csv files for each polynya boundary line series, named as: date_lineX_shift1, date_lineX_shift1c, date_lineX_shift2, and date_lineX_shift2c. Each file contains a specific type of displacement data, described below:a) shift1 – contains information about the ice displacement calculated by solving the Laplace equation between two consecutive boundary lines.
In cases where the line partially moves backward (i.e., two consecutive lines intersect), no result is obtained for that segment.
COLUMNS:
t1 – start datetime;
t2 – datetime of the consecutive image;
area (m²) – area of the polygon between two consecutive lines;
len (m) – length of the polynya boundary line;
wmean (m) – mean distance between two lines;
dt (s) – time difference between two lines;
vel (m/s) – average velocity of the polynya boundary line within the given time interval.b) shift1c – displacement calculated with the Laplace equation relative to the coastline, providing information on how far the polynya boundary is located from the coast.
COLUMNS:
area (m²) – area of the polygon between two consecutive lines;
len (m) – length of the polynya boundary line;
wmean (m) – mean distance between two lines;
t – datetime of the given line.c) shift2 – contains information about displacement calculated using the point-to-point method between two consecutive lines.
Each line is divided into a set of points, and the distance each corresponding point has moved is measured. The mean displacement is then computed from all results.
COLUMNS:
wmean (m) – mean distance between two consecutive lines;
wmin (m) – minimum distance;
wmax (m) – maximum distance;
area (m²) – area of the polygon between two consecutive lines;
t1 – start datetime;
t2 – datetime of the consecutive image;
dt (s) – time difference between two lines;
vel (m/s) – average velocity of the polynya boundary line within the given time interval;
negshift (%) – percentage of the line where displacement is negative (i.e., movement toward the coast).d) shift2c – same method as in shift2, but providing information on the average distance from the coastline.
COLUMNS:
wmean (m) – mean distance between two consecutive lines;
wmin (m) – minimum distance;
wmax (m) – maximum distance;
area (m²) – area of the polygon between two consecutive lines;
t – datetime of the given line;
negshift (%) – percentage of the line where displacement is negative (i.e., movement toward the coast).4. meteo_statistics – file with meteorological data from the Manuela automatic station, containing calculated statistics for the time intervals corresponding to consecutive polynya boundary lines.
The meteorological data are almost always averaged over a slightly longer period than the corresponding polynya time interval. Principally, meteorological measurements were collected at 10-minute intervals; therefore, if the time interval between two consecutive satellite images was 04:05–11:25, the averaging period for the meteorological data was taken as 04:00–11:30.COLUMNS:File NumberStart_Time - datetime in the format 'dd-MM-YYYY HH:mm:SS';End_Time - datetime in the same format as above;Temp_Avg (℃) - average air temperature;Temp_Min (℃) - minimal air temperature in the given time interval;Temp_Max (℃) - maximal air temperature in the given time interval;Pressure_Avg (hPa) - average air pressure;Pressure_Min (hPa) - minimal air pressure in the given time interval;Pressure_Max (hPa) - maximal air pressure in the given time interval;WindSpeed_Avg (m/s) - average wind speed;WindSpeed_Min(m/s) - minimal wind speed in the given time interval;WindSpeed_Max (m/s) - maximal wind speed in the given time interval;WindDir_Avg (°) - average wind direction;WindDir_Min (°) - minimal wind direction in the given time interval;WindDir_Max (°) - maximal wind direction in the given time interval;Humidity_Avg (%) - average air humidity;Humidity_Min (%) - minimal air humidity in the given time interval;Humidity_Max( %) - maximal air humidity in the given time interval;All coordinates are given in the EPSG:32758 – WGS 84 / UTM zone 58S projection.Time is expressed in UTC.