gráfica representativa del "Snowmelt surface melting index" en el continente de "la Antártida", un índice que viene a medir la importancia del deshielo de las nieves. El análisis viene de un trabajo con título “Updated 2008 Surface Snowmelt Trends in Antarctica” llevado a cabo por Marco Tedesco (Department of Earth and Atmospheric Sciences, City College of New York; NASA Goddard Space Flight Center, Greenbelt, Maryland; Joint Center for Earth Systems Technology, University of Maryland Baltimore County)
Con periodo de análisi 1987-2008, parece ser que el índice de deshielo no aprieta demasiado los últimos tiempos, siendo este 2008 el segundo desde 1987 con índice mas bajo. Es lo que tiene el cambio climático.
Para ir haciendo cabalas adjunto también el mapilla con sus colores (tendencia en el numero de dias de deshielo nivoso) y sus zonas diferenciadas.
Adjunto extracto, ya lo traducireis.
Surface snowmelt in Antarctica in 2008, as derived from spaceborne passive microwave observations at 19.35 gigahertz, was 40% below the average of the period 1987–2007. The melting index (MI, a measure of where melting occurred and for how long) in 2008 was the second-smallest value in the 1987–2008 period, with 3,465,625 square kilometers times days (km2 × days) against the average value of 8,407,531 km2 × days (Figure 1a). Melt extent (ME, the extent of the area subject to melting) in 2008 set a new minimum with 297,500 square kilometers, against an average value of approximately 861,812 square kilometers. The 2008 updated melting index and melt extent trends over the whole continent, as derived from a linear regression approach, are –164,487 km2 × days per year (MI) and –11,506 square kilometers per year (ME), respectively.
Negative trends for the period 1987–2008 of the number of melting days (Figure 1b) over the Antarctic Peninsula are observed at a rate down to –2 days per year for internal areas and about –0.7 days per year for coastal areas. Contrarily, positive trends (up to approximately +0.25 days per year) are observed on part of the Larsen Ice Shelf.
In East Antarctica, positive trends are observed over the Amery, West, Shackleton, and Voyeykov ice shelves, with values of up to +0.7 days per year for Shackleton and +0.8 days per year for Amery. Interestingly, the latter shows negative trends (down to –0.3 days per year) for internal areas but positive values for coastal areas.
Large-scale monitoring of ice shelves is an important task for many reasons: Though ice shelves do not contribute directly to sea level rise, they play an important role in keeping the warm marine air at a distance from glaciers; and recent observations also suggest the buttressing effect of ice shelves in preventing acceleration of ice sheets. An increasing surface snowmelt over ice shelves might lead to persisting melt ponds, which, in turn, might contribute to ice shelf disintegration as liquid water fills small surface cracks. Depending on the amount of water and the depth of a crack, the water can deepen the crack and eventually wedge through the ice shelf. Along with surface processes, it is imperative to focus on verifying hypotheses regarding those processes occurring at the ice-ocean boundaries, such as, for example, the thinning of ice shelves driven by ocean-induced melting.
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