Puncak Jaya section of the Jayawijaya Mountain Range still retains small ice caps. Lorentz glaciers are receding rapidly. Some 3,300ha of snowfields REMAINED IN 1992. The main snowfields comprise five separate areas of ice on the outer margins of Mount Puncak Jaya. These include two small fields which feed the Meren and Carstenz glaciers, and a small hanging glacier on the Carstenz Pyramid.
Puncak Jaya in Jaya Wijaya Mountain’s summit consists of several peaks (Jayakesuma/Carstenz Pyramid 4,884m, Ngga Pulu 4,862m, Meren 4,808m) that developed from Tertiary rocks (Miocene). This high area was still covered by wide ice caps (13sq.km) in 1936. These ice caps melted down to an area of just 6.9 km in 1972 and further reduced to 3.3 sq.km by 1991. The remaining ice is now divided into three patches the North Wall Firn, the Meren and Carstenz glacier with only 3 sq.km of ice left. Based on climatic data, a deficit mass balance will continue as the future trend.
The lowland area is a wide swampy plain, covered with virgin forest and intersected by countless winding rivers and streams, mostly tidal. The largest of these rivers empty into the shallow Arafura Sea, which separates the island of New Guinea from Australia. The Regional Physical Planning Program for Transmigration recognised 9 physiographic types and regions (beaches, tidal swamps, meander belts, peat
swamps, alluvial valleys, alluvial fans, dissected terraces, mountains and alpine summits) with 13 major land systems.
Lies within the humid tropical climatic zone. Rainfall in the lowland area averages 3700mm (3160-4100mm per annum). Western winds prevail between October and March, while the Eastern winds blow from April until September. The period from December until March is usually characterized by high waves in the coastal
areas. Daytime temperatures range from 29-32 degrees C in the lowlands, to below freezing above the 4800m contour line. Early morning snow on top of the summits of Mt.
Trikora and Mt. Jaya, or even down to 3800m, occurs regularly, but permanent snow and ice is only to be found in the Mt. Jaya area. In the mountains, the weather conditions are more dependent upon the immediate topography. Rainfall in the higher valleys ranges between 3500 and 5000mm/year.