What is standard deviation of rainfall?

What is standard deviation of rainfall?

Standard deviation Σ [∑ (Xi – Xavg) 2 / (n-1)]1/2 X is the rainfall magnitude in mm, i=1, 2, to n and n is the length of the sample. 3.1 Annual Rainfall Analysis The annual rainfall data is analyzed and the variation in distribution over the area is studied with the statistical parameters.

What is meant by rainfall distribution?

Global distribution of mean annual rainfall (in centimetres). Because rainfall results from the ascent and cooling of moist air, the areas of heavy rain indicate regions of rising air, whereas the deserts occur in regions in which the air is warmed and dried during descent.

What is rainfall variability?

Rainfall variability is measured as the standard deviation of the growth rate of rainfall, which is frequently used in the economic literature. Rainfall variability is defined as the five-year rolling standard deviation of the growth rate of rainfall series.

How do you calculate rainfall intensity of rainfall data?

Formula Of Rainfall Intensity The intensity of rainfall (p) in mm/hr is given by the following general formula: p = 254a / (t+b) mm/hr Where, t = Duration of storm in minutes, a and b are constants. a = 30 and b = 10 when t is 5 to 20 minutes. a = 40 and b = 20 when t is 20 to 100 minutes.

How do you calculate mean rainfall?

Add together all of the monthly rainfall totals in your sample data. You’ll be adding measurements in inches because rainfall is generally measured in inches in the United States. Divide by the number of years in your data set to arrive at the average monthly rainfall for any location.

How is rainfall distributed in India?

Rainfall in India is highly uneven over a period of time in a year. In North-East India, the rainfall increases with altitude. Maximum rainfall (above 200 cms) in India occurs in the western coast, sub Himalayan regions of north-east and Garo, Khasi and Jaintia hills of Meghalaya.

What is seasonal rainfall?

Definitions and basic concepts. Rainfall seasonality can be defined as the irregular distribution of rainfall during a normal year. This irregular distribution means that most of the rainfall occurs in specific months (that can be identified with specific seasons).

What affects rainfall distribution?

Factors controlling the distribution of rainfall over the earth’s surface are the belts of converging-ascending air flow (see doldrums; polar front), air temperature, moisture-bearing winds, ocean currents, distance inland from the coast, and mountain ranges.

What is maximum rainfall?

According to the Guinness Book of World Records, Mawsynram received 26,000 millimetres (1,000 in) of rainfall in 1985. Mawsynram received 745.2 mm of rainfall on 19 August 2015, probably the highest rainfall received by the town to date.

How often does the standard deviation of precipitation occur?

The standard deviation gives an estimate of the range of values around the average that occurs around 67% of the cases (nearly 70% of the time, in other words.) Another way of viewing the standard deviation is by comparing it to the average annual rainfall.

How is the annual decile of rainfall calculated?

The annual decile value must be calculated from the individual yearly totals of rainfall, and cannot be obtained by adding together the monthly deciles. Decile values are used to give an indication of the spread of the observations over the period of record.

Why are accumulations not included in rainfall statistics?

If, for some reason, an observation is unable to be made, the next observation is recorded as an accumulation, since the rainfall has been accumulating in the rain gauge since the last reading. Accumulated totals are not included in statistics such as the Highest Daily Rainfall.

How are rainfall and evaporation statistics the same?

Let’s start by ensuring that the statistical terms for rainfall and evaporation are the same as that used by water balance modellers and the meteorological records. Instead of writing 25th percentile, we will shorten it to 25%ile, and for all others.