in this presentation an overview on the Statistical Analysis of Rainfall Data. followed by quick review of (Collecting, Describing and Summarizing Data. Graphical Data Analysis. Estimating Missing data, Check the Consistency of Precipitation Data. and how to check data quality) Probability / likelihood of occurrence

1. Statistical Analysis of Rainfall Data
Water Resources Research Institute
email: wrri@wrri.org.eg
Web: www.wrri.org.eg
Dr. Ahmed Adel Saleh
email: norahmed1@gmail.com
F.B. | https://www.facebook.com/ahmed.a.saleh.965
Dr. Ahmed Adel Saleh

3. Types of precipitation

4. StatisticsDescriptiveStatistics
statistical techniques used
to summarize and describe
a data set.
Measures of central
tendency
• mean and median, and
dispersion, such as
• range and standard deviation
Displays of data,
• histograms and box-plots.
Inferentialstatistics,or
statisticalinduction,
means the use of statistics
to make inferences
concerning some unknown
aspect.
• hypothesis testing, linear
regression, and prediction.

5. Importance of rainfall statistical data analysis
Collecting, Describing and Summarizing Data
Graphical Data Analysis
Estimating Missing data
Check the Consistency of Precipitation Data
Probability / likelihood of occurrence
An application (HyFran)

6. Colecting, Describing and
Summarizing Rainfall Data

7. Measurement (Population vs samples)

8. Sampling techniques
Random
Sampling
Stratified
Sampling
Uniform
Sampling
Regular
Sampling
Clustered
Sampling
Traverse
Sampling

9. Precipitation description
Amount Intensity Duration Arial extent
Randomness Randomness Randomness Randomness

10. Numerical Summaries (Descriptive Statistics)
• a measure of the center of the data
(mean, median)
• a measure of spread or variability
(variance, standard deviation)
• a measure of the symmetry of the
data distribution (skewness)
• estimates of extremes such as
some large or small percentile
• the complete probability
distribution

11. Mean

12. Graphical Data
Analysis

13. Bar Chart
exploratory data analysis

14. Dot Diagram

15. Ranked Data Plot

16. Histogram

17. Frequency Polygon

18. Cumulative Relative Frequency Diagram

19. Duration Curves

20. Box and Whisker plot

21. Scatterplot

22. Estimating Missing data

23. Interpolation

24. Check the Consistency of
Precipitation Data

25. Checking data homogeneity
• properties or characteristics of different portion of the data series do
not vary significantly.
• Rainfall data for multiple series at neighbouring stations should
ideally possess spatial homogeneity.

26. double-mass curve
Change a rainfall station
Compare two stations

27. Probability / likelihood of
occurrence
How do you use data to understand random variables?

28. Probability distributions

29. Probability distributions

30. Fitting of frequency distributions
Visual comparing

31. exceedance probability or non-exceedance
probability

32. Probability Plots
Assign empirical
probability
Assign order
Sort data

33. Annual exceedance rainfall

34. Data Quality Control

35. Why Data Quality Control ?
Metadata
errors
Location
Period
Instrument
Units
Data
errors
Biases
Fat Finger Errors
Missing minus signs
missing set to zero?
Rounding
Quality
Control
tests
Errors (tmax<tmin, out of bounds)
Comparison with neighbours
Missing Weekend Observations
time of observation
Outlier

37. References
• https://www.youtube.com/watch?v=-ELsdso8pU8
• https://www.slideserve.com/kerri/statistical-hydrology
• https://www.slideshare.net/parimaljha90/precipitation-unit-2
• Frequency Analysis of Extreme Rainfall Events Salaheddine El Adlouni