Regional Climate Trends and Recession Patterns of the Irian Jaya Glaciers

Although considerable research exists investigating the climatic factors affecting tropical glacier mass balance, extensive research on the glaciers of Mt. Jaya, Irian Jaya, Indonesia has been lacking since the early 1970s. Using IKONOS satellite images, the ice extents of the Mt. Jaya glaciers in 2000 and 2002 were mapped. The mapping indicates that the recessional trend which began in the mid-19th century has continued. Between 1972 and 2000, the glaciers lost approximately 67.6% of their area, representing a reduction from 7.2 km2 to 2.35 km2. From 2000 to 2002, the glaciers lost an additional 0.17 km2, representing approximately 7.5% of the 2000 area. Further observations suggest that the equilibrium line altitude may have risen by 100 m over the past 28 years. Differential patterns in ice loss, both spatially and temporally, indicate that a simple rise in temperature may not be sufficient for explaining the observed recession of the Mt. Jaya glaciers. To better understand the climate changes responsible for the observed retreat regional changes in temperature, precipitation and specific humidity are examined. GIS-based solar radiation modeling is used to assess if significant differences in incoming shortwave radiation may also help explain the observed patterns of retreat.