6
Table 1.2 :Formation of clouds at different levels
Source : S.K. Garg (1988)
Formation of clouds can now-a-days be easily detected by means of RADAR
and Weather Satellites and weather can be predicted more or less accurately.
Measurement of Rainfall
Accurate measurement of rainfall is very important for all hydrological studies.
Amount of rainfall and precipitation varies over space and time. Total amount of
rainfall that falls on the earth surface is measured in terms of vertical height
from the horizontal surface with the conception that how much water can be
accumulated from the rainfall that falls in a given area. Measuring device thus
consists of accumulation of rainfall in measuring containers, known as
Rainfall gauges. Rainfall gauges are of two types (i) Non-recording type and
(2) Recording type.
Non-recording rain gauges :
Non-recording rain gauges are most widely used
in India. Indian Metereological Department has installed large number of such
rain gauges throughout the country. These type of rain gauges are known as
non-recording type because they do not record, but only collect the rainfall, which
is then measured by means of graduated cylinders and is expressed in depth,
i.e. mm, cm depth. Various models have been designed for non-recording rain
gauges like Symon's type, which is now replaced by standard rain gauges by
IMD.
