drought index calculation methodlogy

2. INTRODUCTION
• Drought means various things to various people , depending on their specific
interest
• To the farmer drought means a shortage of moisture in the root zone of his crops
• To Hydrologist it suggest below average water level in streams, reservoir and
like.
• Economist define drought as “water shortage that affect adversaly the establish
economy .
• But The world meteorological organization define a Drought as a period of two
consecutive years in which precipitation is less than 60% of normal covering at
least 50% of geographical region.

3. ALTITUDE 309METRE
LATITUDE 21.83°N
LONGITUDE 76.33°E
ANNUAL TOTALNORMAL
RAINFALL(1961-1990)
874mm
ANNUAL TOTAL ACTUAL
RAINFALL(1961-1990)
975mm
STUDY AREA- KHANDWA
Here for studying the palmer drought index khandwa station from
Madhyapradesh have taken.
The following information khandwa given in the table

4. RESEARCH QUESTION
To calculate the measure of departure of actual precipitation from normal during
1961-1990 of khandwa (Madhyapradesh).
OBJECTIVE
To find out the duration of drought effected month on basic of index
value
DATABASE
The data used for this study were taken from Indian daily weather
report, Indian meteorological department under ministry of earth
science of the government of India. The monthly precipitation of 30
year from 1961-1990 collected

5. Index value description
>-4.0 Extreme drought
-3 to -4 Severe drought
-2 to -3 Moderate drought
-1 to -2 Mild drought
-1 to 1 Normal condition
1 to 2 Mild wet spell
2 to 3 Moderate wet spell
3 to 4 Severe wet spell
METHODOLOGY
For calculation of departure of actual precipitation from normal done by Wayne Palmer
method considering the time period fro 1961-1990.
d=p-p^
p = actual precipitation of last 30 year
p^=normal precipitation of last 30 year

6. month actual
precipitation (p)
normal precipitation
(p^)
p-p^ description
January 7.9 6 1.9 Mild wet spell
February 1.9 4.7 -2.8 Moderate drought
March 7.3 7.9 -0.6 Mild drought
April 3.1 1.9 1.2 Mild wet spell
May 7.0 10.1 -3.1 Severe drought
June 83.7 12.1 71.6 Extreme wet spell
July 292.0 240.9 51.1 Extreme wet spell
August 288.0 281.1 6.9 Extreme wet spell
September 241.2 143.4 97.8 Extreme wet spell
October 18.2 26.3 -8.1 Extreme drought
November 14.5 17.7 -3.2 Severe drought
December 10.9 12.3 -1.4 Mild drought
ANALYSIS AND FINDING
Climatic analysis of moisture departure from normal in Khandwa ,(M.P) during 1961-1990
Here ,
P=actual precipitation of 30 year
P^=normal precipitation of 30 year

7. CONCLUSION
khandwa which located on 21.82°N near to line of cancer show that there are some
month which have high rainfall condition (wet spell) while some month have
drought condition in the duration of 30 years from 1961-1990.
The month have drought condition are February , March, May, October, November
and December. Though degree of drought differ.
While January, April, June, July, August ,September are wet spell month.
It also show that normal duration of drought condition from October to December .