Figure 3 shows melting anomaly maps (e.g., the difference between the number of melting days for a given year and the average number of melting days) for the period 1987–2006. During the season 1989–1990, most of the coastal areas in Antarctica were subject to melting for a high number of days (above 60 days on the Palmer Land facing the Bellinghausen sea). Then, during the season 1991–1992, the Ross Ice Shelf was also subject to extensive melting that lasted for more than 30 days. The area affected by melting around the ice shelf was approximately 508,750 Km2 with a melting index (melting area times duration) of 7,020,625 Km2 × day. During the same season, most of the coastal areas experienced melting for more than 10 days above the average, with the exception of the coasts surrounded by the Weddell and Bellinghausen seas (differently from the season 1989–1990). During the 1997–1998 season, most of the coastal areas were subject to melting for a number of days above the average (positive anomaly), although for less days than those observed during the 1991–1992 season. In 1997, unlike 1991, persistent melting occurred along the Peninsula and its interior. Melting also occurred on the Ross Ice Shelf area, with a melting index of 1,284,375 Km2 × day and extent of 135,000 Km2. During the 2004–2005 season, the Ross ice shelf was subject to melting even for inland areas and reaching the Transantarctic Mountains for the first time within the study period. The melting duration over the Ross Ice Shelf in 2004–2005 was shorter than that observed in 1991–1992, with a melting index of 3,143,750 Km2 × day. Melt extent during the 2004–2005 season over the Ross Shelf zone reached 437,500 Km2, close to that observed in 1991–1992, but distributed differently and involving internal areas.
 Figure 4 shows the years when persisting melting was detected for the first time within the study period. Antarctica is divided into seven zones: Peninsula (P), Filchner (F), Dronning Maud Land (D), Amery (A), Wilkes (W), Ross (R), and Marie Byrd Land (M). These will be used in the following section for analysis of long-term trends of melting extent and index. From Figure 4, we see that most of the areas along the coasts experienced melting for the first time in 1987. However, some areas along the coast experienced persistent melting for the first time in the seasons of 1990 (Figure 4, right, P1), 1992 (P2) and 1996 (P3). Note that the 1991–1992 season was also the first one during the study period when extensive melting occurred over the Ross Ice Shelf. Interestingly, over the Transantarctic Mountains and on the edge of the Ross Ice Shelf, an extensive (168,750 Km2) persistent week-long melting occurred continuously between January 6–12, 2005, for the first time in 18 years. For this period, melting occurred for areas located up to 875 Km inland and 2000 m above sea level. These results are consistent with those derived from QuikSCAT data for the overlapping periods [Nghiem et al., 2007]. Figure 5 shows temporal trends of melt extent (dashed line) and melting index (solid line) between 1987 and 2006 for the seven zones of Figure 4 and regression coefficients from linear fitting. Results indicate that, over the whole Antarctica, both melt extent and index have been decreasing since 1987 at a rate of −2,412 Km2/year and −34,567 (Km2 * day)/year, respectively. Nevertheless, considering the different zones separately, we observe both positive and negative trends. The Peninsula (P), Filchner (F), Dronning Maud Land (D), and Marie Byrd Land (M) zones are subject to a decrease on both melt extent and melting index, with the Filchner and Dronning Maud Land zones showing a similar decrease on melt extent (respectively, −1,955 and −2,412 Km2/year), followed by the Peninsula zone (−1,128 Km2/year). Marie Byrd Land is the zone showing the smallest decrease on melt extent with −762 Km2/year, but the highest melting index (−41,783 Km2 * day/year), hence suggesting that the number of days when melting occurred has been decreasing since 1987, followed by Dronning Maud Land (−33,000 (Km2 * day)/year), Peninsula (−22,767 (Km2 * day)/year) and Filchner (−10,688 (Km2 * day)/year). The Ross zone shows an increase on both melt extent (4,449 Km2 * day) and melting index (5,601 (Km2 * day)/year). Lastly, the Amery and Wilkes zones show a slight decrease on the melt extent (−164 Km2/year in the case of Amery and −317 Km2/year for Wilkes) but a more considerable increase on the melting index, respectively, 44,429 (Km2 * day)/year for Amery and 24,991 (Km2 * day)/year for Wilkes. This result suggests that the number of days when melting occurs on the Ross, Amery and Wilkes zones has been increasing since 1987.