Normal Ratio Method

Q. Normal annual rainfall at stations A, B and C situated in meteorologically homogeneous region are 170 cm, 190 cm and 150 cm respectively. In a certain year, station A was inoperative and stations B and C recorded annual precipitation of 160 cm and 140 cm respectively. The annual precipitation at station A is

1. 140 cm
2. 145 cm
3. 151 cm
4. 160 cm

Q. In a watershed, four raingauges I, II, III and IV are installed. The depths of normal annual rainfall of these stations are 60, 75, 80 and 100 cm respectively. The rain gauge at station III went out of order during a particular year. The annual rainfall for that year, recorded at the remaining three stations was 90, 60 and 70 cm. The rainfall at station III can be considered as

1. 60 cm
2. 70 cm
3. 80 cm
4. 120 cm

Q. The normal annual average rainfall at four rain guage stations A, B, C and D are 140, 125 , 115 and 150 cm respectively. During a particular year station D was inoperative and remaining stations A, B and C recorded annual rainfall of 105, 98 and 93 cm respectively. The estimated rainfall at station D would be____cm.

1. 117.135

Q. Consider the following statements:
1. The normal annual rainfall of a station is obtained as the arithmetic average of the successive annual rainfall in the last 30 years.
2. The 'normal rainfall' is updated by deleting the needful number of oldest years data from the record and adding the needful number of most recent years data to the record.
3. The standard deviation computed for the rainfall of the same 30 years of rainfall data is taken as a measure of the variability of the rainfall during the same set of years.
4. If the observed rainfall in any year is less than the current normal annual rainfall, then that year is called a dry year.
Which of the above statements are correct?

1. 1, 2, 3 and 4
2. 1, 2 and 3 only
3. 2 and 4 only
4. 1, 3 and 4 only

Q. Consider the following data recorded at a three rainguage stations

$\begin{array}{cccc}\text{Stations}& \text{A}& \text{B}& \text{C}\\ \text{Normal annual rainfall (mm)}& 300& 400& 500\\ \text{Annual rainfall for year 2010}& 130& \text{X}& 240\end{array}$

The value of 'X' is

1. 178
2. 195
3. 183
4. 190