WeaGETS:

A daily stochastic weather generator for preserving low-frequency of climate

variabilityRoque Vinicio Céspedes

May 3, 2013

MPO 524 - Applied Data AnalysisSpring 2013 Term Project

Professor Brian Mapes

Outline What is a daily stochastic weather generator?

Motivations Application to modeling and climate change

What is WeaGETS? Weather Generator École de Technologie

Supérieure (WeaGETS) My own results

http://www.mathworks.com/matlabcentral/fileexchange/29136-stochastic-weather-generator-weagets

What is a daily stochastic weather generator?

What is WeaGETS? Weather Generator École de Technologie

Supérieure (WeaGETS) is a Matlab-based versatile stochastic daily weather generator (WeaGETS) for producing time series of unlimited length for daily precipitation at a specific weather station site, plus maximum and minimum temperatures.

WeaGETS can be used in climate change studies as a downscaling tool by perturbing the parameters to account for expected changes in precipitation and temperature.

What is WeaGETS? First, second and third-order Markov models are

provided to generate precipitation occurrence. Exponential and gamma distributions are available

to produce daily precipitation quantity. Precipitation generating parameters have options

to be smoothed using Fourier harmonics. A spectral correction approach is included to

correct the well-known underestimation of monthly and inter-annual variability associated with weather generators.

What is WeaGETS?

My Data National Oceanic

and Atmospheric Administration (NOAA) Climate Prediction Center (CPC) 0.25 0.25 Daily U.S. UNIFIED Precipitation Version 1 (1951-2000) rain-gauge-based precipitation

-88 -86 -84 -82 -80 -7824

25

26

27

28

29

30

31

32

Florida RainfallWhole State - 25th Year

Month of the Year

7-D

ay

Ru

nn

ing

Me

an

(m

m /

da

y)

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec0

1

2

3

4

5

6

7

8

9

10

11

12

CPC Obs. (1975)GeneratedCorrected

Florida RainfallWhole State

50-Year Mean Seasonal Cycle

Month of the Year

7-D

ay

Ru

nn

ing

Me

an

(m

m /

da

y)

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec0

1

2

3

4

5

6

7

8

9

10

11

12

CPC Obs. (1951-2000)GeneratedCorrected

Florida RainfallWhole State

50-Year Standard Deviation

Month of the Year

7-D

ay

Ru

nn

ing

Me

an

(m

m /

da

y)

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec2.5

3

3.5

4

4.5

5

5.5

6

6.5

7

CPC Obs. (1951-2000)GeneratedCorrected

CPC Obs. (1951-2000)

J F M A M J J A S O N D1951

1956

1961

1966

1971

1976

1981

1986

1991

1996

0

1

2

3

4

5

6

7

8

9

10

11

12

Generated

J F M A M J J A S O N D1

6

11

16

21

26

31

36

41

46

0

1

2

3

4

5

6

7

8

9

10

11

12

Corrected

J F M A M J J A S O N D1

6

11

16

21

26

31

36

41

46

0

1

2

3

4

5

6

7

8

9

10

11

12

CPC Obs. (1951-2000)

Precipitation Amount (mm / day)

Fre

quen

cy

1 2 3 4 5 6 7 8 9 10 11 120

1000

2000

3000

4000

5000

6000

7000

First Generated 50 Years

Precipitation Amount (mm / day)

Fre

quen

cy

1 2 3 4 5 6 7 8 9 10 11 120

1000

2000

3000

4000

5000

6000

7000

First Correted 50 Years

Precipitation Amount (mm / day)

Fre

quen

cy

1 2 3 4 5 6 7 8 9 10 11 120

1000

2000

3000

4000

5000

6000

7000

Thank you everybody!!!Any question???