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Stationary Markov Model - Stochastic Hydrology - Lecture Notes, Study notes of Mathematical Statistics

The main points which I found very interesting are: Stationary Markov Model, Thomas Fiering Model, Data Generation, Serially Correlated Data, Standard Normal Deviate, Variance and Lag-One, Serial Correlations, Stream Flow Generation, Standard Deviation, Logarithms

Typology: Study notes

2012/2013

Uploaded on 04/20/2013

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Data Generation – Serially Correlated
Data
3%
Standard normal deviate%
First order stationary Markov model
Or
Thomas Fiering model (Stationary)%
( )
2
11 11
1
jx jxjx
XXt
µρµσ ρ
++
=+ +
Stationary w.r.t mean, variance and lag-one
correlation
Known sample estimates of µx, σx, ρ1
Assume X1 (= µx)
Generate values X2, X3, X4, X5 ……
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Download Stationary Markov Model - Stochastic Hydrology - Lecture Notes and more Study notes Mathematical Statistics in PDF only on Docsity!

Data Generation – Serially Correlated

Data

Standard normal deviate

First order stationary Markov model Or Thomas Fiering model (Stationary) ( )

1

j x j x j x

X μ ρ X μ t σ ρ

= + − + −

  • Stationary w.r.t mean, variance and lag-one correlation
  • Known sample estimates of μ x , σ x , ρ 1
  • Assume X 1 (= μ x )
  • Generate values X 2 , X 3, X 4, X 5 ……

First order Markov model with non-stationarity:

  • First order stationary Markov model assumes that the process is stationary in mean, variance and lag- one auto correlation.
  • The model is generalized to account for non- stationarity (mainly due to seasonality/periodicity) in hydrologic data.
  • A main application of this generalised model is in generating the monthly stream flows with pronounced seasonality.
  • Periodicity may affect not only the mean, but all the moments of data including the serial correlations.

Data Generation – Serially Correlated

Data

The monthly stream flow (in cumec) for a river is available for 29 years (12 years data is given here) Example- 6

SL.
YEAR JUN JUL AUG SEP OCT NOV DEC JAN FEB MAR APR MAY
NO.

Time series of monthly stream flow for 29 years 7 0 100 200 300 400 500 600 700 800 900 0 50 100 150 200 250 300 350 400

Assume X 1 = μ 1 = 117.49; σ 1 = 52.24, ρ 1 = 0. μ 2 = 474.5, σ 2 = 150.18, X 1, = = = 521. 9 ( )

X t 1 σ μ ρ μ σ ρ σ

  • − + − ( )

474.5 0.348 117.49 117.

0.335*150.18 1 0.

X 1, =521.67, μ 2 = 474.5; σ 2 = 150.18, ρ 2 = 0. μ 3 = 421.39, σ 3 = 126.53, ρ 3 = 0. X 1, = = 474. 10 ( )

421.39 0.154 521.67 474.

0.377 *126.53 1 0.

0 50 100 150 200 250 300 350 400 450 500 JUN JUL AUG SEP OCT NOV DEC JAN FEB MAR APR MAY Mean

Observed

Generated

-­‐0. -­‐0. -­‐0. 0

1

JUN JUL AUG SEP OCT NOV DEC JAN FEB MAR APR MAY Lag-1 correlation

Observed

Generated

Where Y

i,j+

= ln (X

i, j+

refer to the mean, standard deviation

and lag one correlation of logarithms of original data

Data Generation – Serially Correlated

Data

1 1 1

j j j j j j j

y

i j y y ij y i j y y

y

Y Y t

y (^) j y (^) j yj

 - Lag- S.No. Month Mean Stdev. 
  • 1 JUN 117.49 52.24 0. correlation
  • 2 JUL 474.50 150.18 0.
  • 3 AUG 421.39 126.53 0.
  • 4 SEP 145.94 77.65 0.
  • 5 OCT 66.61 30.67 0.
  • 6 NOV 22.99 13.26 0.
  • 7 DEC 10.30 9.82 0.
  • 8 JAN 5.55 9.16 -0.
  • 9 FEB 1.91 0.74 0.
  • 10 MAR 1.09 0.54 0.
  • 11 APR 0.76 0.51 0.
  • 12 MAY 0.80 0.60 -0. - Lag- S.No. Month Mean Stdev.
    • 1 JUN 125.69 59.30 0. correlation
    • 2 JUL 469.36 142.10 -0.
    • 3 AUG 365.98 130.60 0.
    • 4 SEP 140.40 78.60 0.
    • 5 OCT 65.28 33.89 0.
    • 6 NOV 22.33 12.40 0.
    • 7 DEC 10.68 8.30 0.
    • 8 JAN 7.69 7.13 -0.
    • 9 FEB 1.95 0.59 0.
  • 10 MAR 0.95 0.52 0.
  • 11 APR 0.60 0.47 0.
  • 12 MAY 0.68 0.50 0. - Lag- S.No. Month Mean Stdev.
    • 1 JUN 4.64 0.54 0. correlation
    • 2 JUL 6.11 0.33 0.
    • 3 AUG 6.00 0.31 0.
    • 4 SEP 4.86 0.49 0.
    • 5 OCT 4.10 0.44 -0.
    • 6 NOV 2.71 2.02 0.
    • 7 DEC 1.83 1.91 0.
    • 8 JAN 1.13 1.77 0.
    • 9 FEB 0.12 2.15 0.
  • 10 MAR -0.66 2.42 0.
  • 11 APR -1.05 2.32 0.
  • 12 MAY -1.08 2.35 -0. - Lag- S.No. Month Mean Stdev.
    • 1 JUN 4.74 0.64 0. correlation
    • 2 JUL 6.09 0.31 -0.
    • 3 AUG 5.86 0.33 0.
    • 4 SEP 4.82 0.50 0.
    • 5 OCT 4.08 0.48 0.
    • 6 NOV 2.64 1.45 0.
    • 7 DEC 1.76 1.40 0.
    • 8 JAN 1.25 1.31 0.
    • 9 FEB 0.33 1.93 0.
  • 10 MAR -1.10 2.41 0.
  • 11 APR -1.56 2.42 0.
  • 12 MAY -1.60 2.42 0.

0

1

2

3 JUN JUL AUG SEP OCT NOV DEC JAN FEB MAR APR MAY Standard Deviation

Observed

Generated

-­‐0. -­‐0. 0

1

JUN JUL AUG SEP OCT NOV DEC JAN FEB MAR APR MAY Lag-1 Correlation

Observed

Generated