Why does permanent snow line exist at lower altitude in western Nepal (4000m) than eastern Nepal (5000m)?
Answers
The interplay of altitude and latitude affects the precise placement of the snow line at a particular location. At or near the equator, it is typically situated at approximately 4,500 metres (14,764 ft) above sea level. As one moves towards the Tropic of Cancer and Tropic of Capricorn, the parameter at first increases: in the Himalayas the permanent snow line can be as high as 5,700 metres (18,701 feet), whilst on the Tropic of Capricorn, no permanent snow exists at all in the Andes, because of the extreme aridity. Beyond the Tropics, the snow line becomes progressively lower as the latitude increases, to just below 3,000 metres (9,843 ft) in the Alps and falling all the way to sea level itself at the ice caps near the poles.[citation needed]
This 1848 "Sketch showing the actual elevation of the Snow Line in different Latitudes" by Alexander Keith Johnston shows the snow lines of mountains in America, Europe and Asia
In addition, the relative location to the nearest coastline can influence the altitude of the snow line. Areas near a coast might have a lower snow line than areas of the same altitude and latitude situated in a landmass interior due to more winter snowfall and because the average summer temperature of the surrounding lowlands would be warmer away from the sea. (This applies even in the tropics, since areas far from the sea will have larger diurnal temperature ranges and potentially less moisture, as observed with Kilimanjaro and presently glacier-free Mount Meru.) A higher altitude is therefore necessary to lower the temperature further against the surroundings and keep the snow from melting.[citation needed]
Furthermore, large-scale oceanic currents such as the North Atlantic Current can have significant effects over large areas (in this case warming northern Europe, extending even to some Arctic Ocean regions).[citation needed]
In the Northern Hemisphere the snow line on the north-facing slopes is at a lower altitude, as the north-facing slopes receive less sunlight (solar irradiance) than south-facing slopes.the converse will occur in the Southern Hemisphere.
Glacier equilibrium line
The glacier equilibrium line is the point of transition between the accumulation zone and ablation zone. It is the line where the mass of these two zones is equal. Depending on the thickness of the glacier, this line can seem as though it is leaning more towards one zone but it is determined by the actual mass of ice in either zone. The rates of ablation and accumulation can also be used to determine the location of this line.
This point is an important location to use in determining whether a glacier is growing or shrinking. A higher glacier equilibrium line will indicate that the glacier is shrinking, whereas a lower line will indicate that the glacier is growing. The terminus of a glacier advances or retreats based on the location of this equilibrium line.
Scientists are using remote sensing to better estimate the locations of this line on glaciers around the world. Using satellite imagery, scientists are able to identify whether the glacier is growing or receding. This is a very helpful tool for analyzing glaciers that are difficult to access. Using this technology we can better gauge the effects of climate change on glaciers around the world.
Answer:
since the Northeast monsoon winds bring precipitation to eastern Nepal