Antarctica - Release Level 05 (RL-05)Below are updated results continued from our recent paper Harig and Simons , Earth Planet. Sci. Let., 415, 134-141, 2015. http://dx.doi.org/10.1016/j.epsl.2015.01.029. As of the last update January 2015 here, these results use the Release level 5 UTCSR (http://www.csr.utexas.edu/grace/) data solutions from January 2003 up to and including June 2014.
In the latest trend estimate from our paper Antarctica as a whole has lost -92 Gigatons per year since the beginning of 2003 (Fig 1, panel e). We also estimate mass changes for smaller regions within Antarctica (panels a-d), the most dramatic of these being West Antarctica which has lost -121 Gigatons per year of ice mass and has been strongly accelerating.
Figure 1: Total mass change trends for regions around Antarctica. The solid black line is the raw GRACE monthly solution. Here we use a bandwidth of 60 spherical harmonic degrees and a 0.5 degree buffer region. The solid blue line is the best-fitting exponential trend. For more technical details please see the Methods/Code webpage.
Figure 2: Geographical pattern of the cumulative mass change over Antarctica for the period between 1/2003 and 6/2014. The integral value "Int" for the entire epoch is shown in Gigatons. For more technical details please see the Methods/Code webpage.
The Antarctic Peninsula has experienced mass loss of −27 ±2 Gt/yr (see Fig. 1b). Over the last 10 years this trend has shown an acceleration of −5 ±1Gt/yr2. These aggregate values blur distinct changes between the northern and southern halves of the Peninsula. By 2003, several areas of the northern Peninsula had shown speed-up of glaciers visible to remote sensing, including the Larsen A and B areas, and continuous speed-up and retreat of west coast glaciers. This northerly mass loss is consistently detected by GRACE in all years of data availability, in agreement with other remote sensing data. The southern half of the Peninsula has experienced an acceleration towards increasing amounts of mass loss over the past decade. This has increased the overall mass losses, as has been seen in other recent studies as well.
Figure 3: Annual maps of mass change over West Antarctica (top two rows) and the Antarctica Peninsula (bottom two rows) from 2003 to 2013. For every year we show the difference of the signal estimated between January of that year and January of the next. The integral values of the mass change per year are shown as "Int", expressed in Gigatons. For more technical details please see the Methods/Code webpage.
References (see also About/Publications)Harig, Christopher and Frederik J. Simons. Accelerated West Antarctic ice mass loss continues to outpace East Antarctica gains. Earth Planet. Sci. Let., 415, 134-141, 2015. http://dx.doi.org/10.1016/j.epsl.2015.01.029