Statistical represtation of three different rainfall station of bangladesh

1. STATISTICAL
REPRESENTATION OF
THREE DIFFERENT
RAINFALL STATIONS OF
BANGLADESH
Welcome to the presentation on

2. Presented by
Nazmul Hasan Diptu
#ID: CEN 062 09450
Stamford University of
Bangladesh
MD. Arman Uddin
#ID: CEN 063 09514
Stamford University of
Bangladesh
MD. Akramul Haque
#ID: CEN 062 09503
Stamford University of
Bangladesh

3. Supervised by
Mohsena Lopa
Lecturer
Department of Civil Engineering
Stamford University Bangladesh.

4. Topic to be covered in this presentation.
Introduction
Objective of the
study
Methodology
Analysis Rainfall
Data
Conclusions and
Recommendations

5. Introduction
• Four distinct seasons can be recognized
in Bangladesh from the climatic point of
view:
Seasons Months
Dry Winter Season December, January,
February
Pre-Monsoon Season March, April, May
Rainy Monsoon Season June, July, August,
September
Post-Monsoon Season October, November,
December

6. Introduction
cont.
• We are statistically analysing the rainfall data
of three districts of Bangladesh, namely
Dhaka, Comilla and Chandpur, respectively.
• We have analyzed the rainfall data of three
districts and determine the amount of rainfall
in the future relative to those three districts
and have determined the location of climate
change by analyzing the increase and
decrease of rain.

7. Maps
Dhaka
Chandpur
Comilla

8. Objectives
of the study
To analyze data using the statistical
methods of the different stations.
To monitor how the maximum
rainfall changes and checking the
return period.
To check the consistency of rainfall
data in different stations of
Bangladesh.

9. Methodology
The meteorological data used in this study have
been taken from Bangladesh Meteorological
Department (BMD) rainfall experiment.
For this study Monthly and Daily rainfall data
conducted between 1970 and 2016.
At first Monthly total Rainfall was calculated
from daily precipitation data.

10. Analysis
Rainfall
Data
Presentation of Rainfall Data Commonly
used methods are:
Hyetograph
Mass curve of rainfall
Pont rainfall
Moving Average

11. Hyetograph

12. Hyetograph
Hyetograph is one type of histogram. This
hyetograph is a plot of the average rainfall
intensity compared to the year. Hyetographs
originate from mass curves and usually appear
as iterations. This is a very convenient way to
present storm features and is especially
important in developing pattern storms to
predict the final flood. The area covered by
the hyetograph represents the total rainfall
during the period.

13. Dhaka District Hyetograph
0.0
50.0
100.0
150.0
200.0
250.0
300.0
Average
Rainfall
Year
Average Rainfall

14. Comilla District Hyetograph
0.0
50.0
100.0
150.0
200.0
250.0
300.0
Average
Rainfall
Year
Average Rainfall

15. Chandpur District Hyetograph
0.0
50.0
100.0
150.0
200.0
250.0
300.0
350.0
400.0
Average
Rainfall
Year
Average Rainfall

16. Data observations in Hydrograph
0
50
100
150
200
250
300
350
400
Average
Rainfall
Data
Year
Dahka Comilla Chandpur

17. Test for Consistency
of Data

18. Double
mass curve
Changes in the gauge location, exposure,
instrumentation or observational procedure
may cause a relative change in the
precipitation measurement.
Double-mass analysis tests the consistency
of the record at station by comparing its
accumulated annual or seasonal
precipitation with the concurrent
accumulated values of mean precipitation
for a group of surrounding stations

19. Double
mass curve
cont.
A double mass curve has been created by
calculating the Annual rainfall of the Sum
of Annual rainfall in each district and the
Average Annual rainfall of the Sum of
Average annual rainfall in three districts.
The final value of the Annual rainfall of
each district has been found through the
equation obtained from the double mass
curve.

20. Double-Mass Curve of Annual Rainfall of Dhaka District.
y = 3.9941x - 2100.7
0
10000
20000
30000
40000
50000
60000
70000
80000
90000
100000
0 5000 10000 15000 20000 25000
Sum
of
Dhaka
(annual
rainfall)
Sum of avg Annual Rainfall of all District

21. Double-Mass Curve of Annual Rainfall of Comilla District.
y = 3.9867x - 329.16
0
10000
20000
30000
40000
50000
60000
70000
80000
90000
100000
0 5000 10000 15000 20000 25000
Sum
of
Comilla
(annual
rainfall)
Sum of avg Annual Rainfall of all District

22. Double-Mass Curve of Annual Rainfall of Chandpur District.
y = 4.0425x + 261.8
0
10000
20000
30000
40000
50000
60000
70000
80000
90000
100000
0 5000 10000 15000 20000 25000
Sum
of
Chandpur
(annual
rainfall)
Sum of avg Annual Rainfall of all District

23. Point Rainfall

24. Point
Rainfall
To create a bar chart of the annual
rainfall of each district, we calculate
the average annual rainfall with the
help of annual rainfall and plot it in
the graph.
We can see the years of maximum
annual rainfall and minimum
annual rainfall due to the Bar Chart.

25. Point Rainfall
cont.
• In 1984 we saw maximum annual
rainfall in Dhaka and Chandpur
districts at 3021 mm, and 4305
mm, respectively, and Comilla
district in 1991 saw a maximum
of 3914 annual rainfall.
• We saw minimum annual rainfall
in Dhaka district in the 1992 year,
Comilla district in the 1974 year
and Chandpur district in the 1976
year, respectively,1144mm,
1173mm, and 362mm.

26. Bar Chart of Annual rainfall of Dhaka District
0
500
1000
1500
2000
2500
3000
3500
Annual
Rainfall
Year
Annual Rainfall of Dhaka Mean 20% Less then mean

27. Bar Chart of Annual rainfall of Comilla District
0
500
1000
1500
2000
2500
3000
3500
Annual
Rainfall
Year
Annual Rainfall Of Comilla(mm) Mean 20% Less then mean

28. Bar Chart of Annual rainfall of Chandpur District
0
500
1000
1500
2000
2500
3000
3500
4000
4500
5000
Annual
Rainfall
Year
Annual Rainfall Mean 20% Less then Mean

29. Three-year
Moving Mean

30. Three year
moving
Average
Moving averages are usually used to
smooth out long-term trends in the
movement of data.
Calculate the Annual rainfall of three
consecutive moving means of annual
rainfall to find out the three years
moving mean of each district and plot it
in the graph.

31. Three year moving Average of Dhaka District
0.0
500.0
1000.0
1500.0
2000.0
2500.0
3000.0
Annual
Rainfall
Year
3-year moving mean Mean

32. Three year moving Average of Comilla District
0.0
500.0
1000.0
1500.0
2000.0
2500.0
Annual
Rainfall
Year
3-year moving mean Mean

33. Three year moving Average of Chandpur District
0.0
500.0
1000.0
1500.0
2000.0
2500.0
3000.0
3500.0
4000.0
Annual
Rainfall
Year
3-year moving mean(Col. 3/3) Mean

34. Return Period of
annual rainfall

35. • A return period, also known as a
recurrence break or recurrence
interval, is the average time or
approximate average time
between earthquakes, floods,
landslides, or river discharge
flows.
• It is a statistical measure usually
based on historical data over an
extended time and is usually
used for risk analysis.
Return
Period of
annual
rainfall

36. Return Period
of annual
rainfall cont.
Estimating the annual rainfall with
return periods of 10 years and 50
years.
Probability of annual rainfall of
magnitude equal to or exceeding
100 cm occurring in three district.
75% dependable annual rainfall in
this district.

37. Frequency of
Rainfall

38. Maximum
probability
of annual
rainfall
We have measured the approximate
maximum rainfall over the next twenty
years.
We have estimated the amount of
maximum rainfall in the next fifteen
years.
We have calculated the maximum
number of years of maximum rainfall
in the next twenty years.

39. Maximum
probability of
annual rainfall
In this estimated calculation, we
get some essential ideas about
natural disasters (flood, storm, and
drought) in three districts that can
get forecasts.

40. Conclusions and
Recommendations

41. Conclusion and
Recommendations
We have got some essential ideas
about natural disasters (flood,
storm, drought) in three districts
that can be forecasted.
There is a need to increase more
rain gauge stations in Bangladesh.
This can help improve the
consistency of the data.

42. Conclusion and Recommendations cont.
We can make it more acceptable
by collecting a lot of data using
more modern software.
If we could collect data
directly, this task may be
more effective.

43. Thank You very much
for your patience hearing