Surface melt in Antarctica 1979 - 2015


A dataset of daily surface melt in Antarctica is distributed, along with derived higher-level indexes. Surface melting is retrieved from passive microwave radiometer data (SMMR and SSM/I) using the algorithm developed by Torinesi et al. 2003 and Picard and Fily 2006. The microwave data are provided by NSIDC in two datasets: SMMR and SSM/I. The surface melting is provided with a spatial resolution of 25 km but the underlying data are at about 60 km resolution. The temporal resolution is 1 day (2 days before 1988) and records are almost continuous since 1979.
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Condition of use.

The dataset and other information on this page are provided "AS IS", without warranty of any kind. Ackownledgment in publications will be appreciated and the following citation is suggested:

G. Picard, M.Fily, 2006, Surface melting observations in Antarctica by microwave radiometers: correcting 26 year-long timeseries from changes in acquisition hours. Remote Sensing of Environment.

The dataset and other information are freely available but consider to subscribe to the mailing list osug-melt mailing-list to be informed of the updates and mistakes. Updates of the datasets should be provided yearly depending on the availability of SSMI/I data from NSIDC.

Daily Surface Melting Dataset.

This dataset includes the melted/not melted status of every pixel on the reduced Southern stereographic polar grid for every day since 1st April 1979. This grid is a cropped version of the Southern stereographic polar grid used by NSIDC. The grid has a 25 x 25 kmē resolution (see NSIDC information). The reduced grid size is 231 x 201 pixels. The upper left pixel is at coordinate (40,70) in the NSIDC Polar grid and the lower right pixel at coordinate (271,271). For ease of use, latitude and longitude of each pixel are included in the dataset.

The pixels are classified as follow:

The mask excludes the ocean as well as areas never experiencing melting. The mask does not change over time which has some implications where the coast line change. For instance, Larsen A and B Ice Shelves are not masked out although they desintegrated since 1995. Melting information after desintegration are irrelevant in this area, and any trend analysis must be corrected from this change.

The dataset file is provided in NetCDF format. It includes the data and metadata (such as the latitude/longitude, etc). For more detailed information see the ncdump output.

The most up-to-date dataset:
Surface Melting 1979-2015 Dataset ver 1.0 [ DOWNLOAD (9.0Mb) ]. This archive includes two files, one with missing satellite data filled by interpolation and one without (called raw) if you need to implement your own gap filling method.

The original dataset used with the publication of Picard et al. 2006:
Surface Melting 1979-2006 Dataset ver 1.0 [ DOWNLOAD (437Mb !!!) ]

Note: The differences between the original and the up-to-date datasets for years in common are explained by improvements in SSM/I brightness temperature dataset (Version 2 released in July 2006, see http://nsidc.org/data/docs/daac/nsidc0001_ssmi_tbs.gd.html)

Cumulative Melting Surface.

The Cumulative Melting Surface (CMS) is defined as the number of melted pixels for an entire summer and an entire region multiplied by the surface of a pixel (25 x 25 kmē). Its unit is expressed in day kmē. The Antarctic regions used here were defined by Zwally et Fiegles, 1994. See figure:

Antarctic Zones

The CMS for the different regions have been corrected from changes in acquisition hours due to satellite replacements with the method developed by Picard and Fily, 2006. Both corrected and uncorrected CMS are available for download. To our opinion, the correction efficiently reduces errors for some regions (Peninsula, DML, Amery, Wilkes, MBL), but is less efficient or may add new errors for other regions (Filchner, Ross). In the latter regions, we recommend to use both the corrected and uncorrected CMS.

The file is organized in two columns. The first is the year corresponding to the end of the summer (e.g. 1980 corresponds to summer 1979/1980) and the second the CMS expressed in 106 km2 day.

Corrected CMS ver 1.0 (1979/1980-2005/2006): [ DOWNLOAD]

Uncorrected CMS ver 1.0 (1979/1980-2005/2006): [ DOWNLOAD]

Surface melting maps.

The maps represent the number of days with surface melt. During the SMMR period (1979-1987), the brightness temperature were linearly interpolated on every day before the application of the melt detection algorithm.

surface melting in 1979/1980 surface melting in 1980/1981 surface melting in 1981/1982 surface melting in 1982/1983 surface melting in 1983/1984 surface melting in 1984/1985 surface melting in 1985/1986 surface melting in 1986/1987 surface melting in 1987/1988 surface melting in 1988/1989 surface melting in 1989/1990 surface melting in 1990/1991 surface melting in 1991/1992 surface melting in 1992/1993 surface melting in 1993/1994 surface melting in 1994/1995 surface melting in 1995/1996 surface melting in 1996/1997 surface melting in 1997/1998 surface melting in 1998/1999 surface melting in 1999/2000 surface melting in 2000/2010 surface melting in 2001/2002 surface melting in 2002/2003 surface melting in 2003/2004 surface melting in 2004/2005 surface melting in 2005/2006 surface melting in 2006/2007 surface melting in 2007/2008 surface melting in 2008/2009 surface melting in 2009/2010 surface melting in 2010/2011 surface melting in 2011/2012 surface melting in 2012/2013 surface melting in 2013/2014 surface melting in 2014/2015

Bibliography.


Last update: Feb 2016