INTRODUCTION
Ice on earth takes a variety of forms ranging from snow cover to continental ice sheets to mountain glaciers. The origin of these forms and their variations over short or long periods of time depends to a large extent on the details of their thermal history. Microclimates control their short term behaviour and the long term effects are observed in global (or regional) climate affecting the movement and distribution of moisture. Massive reorganizations of the ocean-atmosphere system are the key events that link cyclic changes in the earth's orbit to the advance and retreat of ice sheets (Broker & Denton, 1990). For over three decades, evidence has mounted that the glacial cycles are ultimately driven by astronomical factors: slow cyclic changes in the eccentricity of the earth's orbit and the tilt and orientation of its axis of rotation. As large bodies of ice exist near poles and at higher altitudes, the present article deals with the cold environments over the Himalaya, theArctic and the Antarctic. The Himalayan region has been considered to encompass the mountain area from the Pamir region adjoining the Karakoram-Hindukush-Zaskar ranges in the West-northwest, the Tibetan plateau at the centre bordered by the Kunlun Shan in the North and the Heng Tuan Shan in the East and by the great Himalayan range in the South. The Chinese call it the Qinghai-Xizang Plateau (Fig. 1). In this perennially cold region, the locale of the three peaks. Everest, Lhotse and Nuptse resemble the environment of a pole and the Himalayan region resembles the Arctic and the Antarctic. The prolonged periods of day and night over the North and South polar regions are not existing in the Himalayan region. But the outflow of cold from the Himalayas produces a steeper temperature gradient due to their extremely high altitude and proximity to the highly energetic tropical environment. Unlike the other two poles, the Himalayan region has long supported civilizations, and yet it is one of the least explored geographical areas on earth deserving a renewed thrust from international scientific community, helping those who live in the region and its environs.
HIMALAYA
Himalaya, the abode of eternal snow forms a unique environment: the highest mountain environment on earth where snow and icy environmental conditions rival those existing at polar regions (Bahadur, 1972, 1992). Also called the Roof of the World the region extends through eight countries: Russia, The Peoples Republic of China, India, Bhutan, Myanmar, Nepal, Pakistan and Afghanistan. The conditions on gale-whipped Himalayan summits covered by perennial snow and ice above 5000 m altitude resemble the environment in Arctic and Antarctic polar regions. The Leader of the 1963 American Scientific Expedition to Everest Norman Dyhrenfurth called it a third pole (Miller, The Himalayas: a third polar region 183 1964). The triumvirate of peaks Everest (8903 m), Lhotse (8501 m) and Nuptse (7879 m) and the upper Khumbu glaciers (4600 m to 8200 m) have been called in a meteorological sense, the "Mother Goddess of the Winds" (The Tibetan name of Mt. Everest is Chomolongma — the goddess mother of the world). The extremely high altitude of Himalaya probably provides a unique glacial climate on earth and there is need to study the primary atmospheric processes operating here which affect regional and global weather.
Climate of the Himalaya
The Himalaya are characterized by cold arid to wet tropical conditions seasonal alterations of dry and moist conditions in wide range of altitudes. The climate of the Himalaya may be said to consist of four broad and contrasting regions (Mani, 1981):
— the rain forest of the East, ranging in altitude to 2000 m;
— the wet alpine zone above the tree-line rising to 6000 m or more;
— transitional semi-wet region in the central portion of the mountains;
— an arid region in the Hindu Kush far to the West.
The four parallel ranges which constitute the Himalaya and the Sub, Lower, Higher and Tibetan Himalayan Ranges have their own physiographic features, geological history and climate. The following aspects are noteworthy:(Read more)
[1] [Snow and Glacier Hydrology (Proceedings of the Kathmandu Symposium, November 1992).IAHSPubl.no. 218,1993]
[2] National Centre for Medium Range Weather Forecasting, Department of Science and Technology, Government of India, New Delhi 110016,India
