A tropical cyclone is a
A cyclone is a large low pressure region with circular wind motion. Two types of cyclones are recognized viz., tropical cyclones and extratropical cyclones. A tropical cyclone is a wind system with an intensely strong depression. The normal areal extent of a cyclone is about 100-200 km in diameter. The isobars are closely spaced and the winds are anticlockwise in the Northern hemisphere.
Orographic precipitation occurs due to air masses being lifted to higher altitudes by
The moist air masses may get lifted-up to higher altitudes due to the presence of mountain barriers and consequently undergo cooling, condensation and precipitation, such a precipitation is known as orographic precipitation.
The average annual rainfall over the whole of India is estimated as
Variability of annual rainfall in India is
The standard Symons' type raingauge has a collecting area of diameter
The standard recording raingauge adopted in India is of
Natural syphon type is adopted as the standard recording type rainguage in India. It is also known as float-type gauge.
The following recording raingauges does not produce the mass curve of precipitation as record:
The Tipping-bucket type gauge gives data on the intensity of rainfall.
When specific information about the density of snowfall is not available, the water equivalent -of snowfall is taken as
A, B and C are three catchments each having an area of about 10,000 km2 situated in an arid zone, mountainous region of a tropical zone and flat region of a tropical zone respectively. The desirable number of hydrometeorological stations for each of these three areas, NA, NB and NC respectively will be such that
The monthly rainfall at a place. A during September 1982 was recorded as 55 mm above normal. Here the term Normal means.