g4: dr . saiful islam, iwfm, buet, bangladesh md. raqubul hasib , iwm, bangladesh

Climate Change Projections for Selected Polders of the Coastal Region to assess impact

on Agriculture and Water Resources

G4:

Dr. Saiful Islam, IWFM, BUET, BangladeshMd. Raqubul Hasib, IWM, Bangladesh

ShatkhiraKhulna

Patuakhali

Polder

Study Area - Polders3, 30, 43/2F

Polder-3

Polder 30

Polder 43/2F

Climate projections are performing on the basis of three extreme emission scenarios

A2 scenarios - High A1B scenarios – Moderate B2 scenarios – Low (on going)

Two GCMs are- HadCM3, CGCM3

Climate Change Scenarios

General Approach to Downscaling

Applicable to: •Sub-grid scales

(small islands, point processes)

•Complex/ heterogeneous environments

•Extreme events

Predictands (to predict)

1. Maximum air temperature.2. Minimum air temperature.3. Precipitation

Predictors (26 variables such as-MSL, RH, WIND, HEGIHT, TEMPERATURE

at different atmospheric levels

Statistical downscaling

Tools used for statistical downscaling

Following procedure are performed during downscaling:

Check Quality of the data◦ Screening of predictor variable◦ Screening of predictor variable.

Calibration and validation of GCM with station data

Synthesis of observed data using weather generator

Generation of Climate change scenario using calibration parameters

Methods of Processing

Climate Change Projections for Polder 3 (Satkhira)

Model calibration at Satkhira for Tmax (HadCM3 A2)

Predictors Partial rSpecific Humidity 0.803

RH 0.496

RH at 850 hpa 0.212

RH at 500 hpa 0.200Mean E% 27.70Mean SE 1.849

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

5

10

15

20

25

30

35

40

45Monthly Variation of Explained variance (%) in Satkhira

Tmax (1961-1980)

Month

Exp

lain

ed V

aria

nce

(%)

Model calibration at Satkhira for precipitation (HadCM3 A2)

Predictors Partial r

Wind Direction at 500hpa 0.167

RH at 500hpa 0.153

Mean E% 11.500

Mean SE 20.035 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec0

5

10

15

20

25

30

35

40

45

Monthly Variation of Explained variance (%) in Satkhira

Precipitation (1961-1980)

Exp

lain

ed v

aria

nce

(%)

Validation of Maximum Temperature for HadCM3 A2 scenario


5

10

15

20

25

30

35

40

Validation of downscaled monthly mean Tmax at satkhiraobserved data (1981-2000)

modeled data (1981-2000)

month

Tm

ax(d

eg. C

)

0 5 10 15 20 25 30 35 40 450

5

10

15

20

25

30

35

40

45

Q-Q plot (Satkhira)

Tmax modeled (1961-2000)

Tm

ax o

bser

ved

(196

1-20

00)

Validation of Mean precipitation for HadCM3 A2 scenario


2

4

6

8

10

12

14

16

Downscaled mean precipitation (Satkhira)Observed mean precipitation (1981-2000)Modeled mean precipitation (1981-2000)

Month

Mea

n pr

ecip

itatio

n (m

m/d

ay)

0 10 20 30 40 50 60 700

10

20

30

40

50

60

70Q-Q plot (Satkhira)

Modeled data (1961-2000)

Obs

erve

d da

ta (1

961-

2000

)

Maximum Temperature Projections considering A2 and A1B Scenarios


5

10

15

20

25

30

35

40

45

Monthly Tmax in three different time period (satkhira)HadCM3 A2 scenario

Observed Tmax (1961-1990)

Forcasted Tmax (2011-2040)



Month

Tem

pera

ture

(Deg

. C)


5

10

15

20

25

30

35

40

Predicted maximum temperature in three different time period (Satkhira) CGCM3 A1B scenario

observed Tmax(1961-1990)

forcasted Tmax (2011-2040)



Month

Tem

pera

ture

(Deg

.C)

Maximum Increase in monsoon period

Maximum Increase in pre monsoon period

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

2

4

6

8

10

12

14

16

Mean precipitation in different time period (satkhira)

Base period (1961-1990)Period A (2011-2040)Period B (2041-2070)Period C (2071-2099)

Month

Prec

ipita

tion

(mm

/day

)

Increase mean mean precipita-tion in monsoon period

Increase mean mean pre-cipitation in pre mon-soon period

Increase mean mean precipitation in post monsoon period

Precipitation projections considering HADCM3 A2 Scenarios

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

2

4

6

8

10

12

14

16

Mean precipitation in different time period (Satkhira)


Month

Prec

ipita

tion

(mm

/day

)

Increase mean precipi-tation in monsoon pe-riod

Increase precipi-tation in pre monsoon and dry period

Precipitation projections considering A1B Scenarios

Summary for Polder 3 (Satkhira)

Temperature Change : Temperature will increase gradually in

the future period.

Rate of Temperature change is greater for A2 than A1B .

Precipitation change:

For A2 scenario mean precipitation will increase in overall period of the year. Consecutive dry day will increase in monsoon and pre monsoon period, that denotes that rainfall intensity or rainfall duration may increase for that period.

For A1B scenario mean precipitation will increase in monsoon and pre-monsoon period.

Climate Change Projections for Polder 30 (Khulna)


5

10

15

20

25

30

35

40

45

Predicted maimum temperature in three different time period (Khulna) HadCM3 A2 scenario

observed Tmax (1961-1990)

predicted Tmax (2011-2040)

Predicted Tmax (2041-2070)


Month

Tem

pera

ture

(deg

.C)


5

10

15

20

25

30

35

40

Predicted maimum temperature in three different time pe-riod (Khulna) CGCM3 A2 scenario

Observed Tmax (1961-1990)




Month

Tm

ax (D

eg.C

)

Maximum Increase of in monsoon period

Maximum Increase in Pre monsoon period


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

2

4

6

8

10

12

14

16

18

Mean precipitation in different time period (Khulna)


Month

Prec

ipita

tion

(mm

/day

)

Increase of mean precipitation in monsoon and post monsoon period

Increase of mean precipitation in pre-monsoon period

Precipitation Projections considering HadCM3 A2 Scenarios

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

2

4

6

8

10

12

14

Mean Precipitation in different time period (Khulna)


Month

Prec

ipita

tion

(mm

/day

)

Increase of mean precipitation in post monsoon period

Increase of mean precipitation in pre monsoon period

Shifting of peak precip-itation time

Precipitation Projections considering A1B Scenarios

Precipitation Change : For A2 scenario mean precipitation will increase in

pre-monsoon, post monsoon and monsoon period.

For the case of A1B scenario it is observed that mean precipitation will increase in pre-monsoon, post monsoon and monsoon period. Precipitation of the year will be delayed about one month during monsoon

Summary for polder 30 (Khulna)

Climate Change Projections for Polder 43/2F

(Patuakhali)


5

10

15

20

25

30

35

Predicted minimum temperature in three different time period (Patuakhali) HadCM3 A2 scenario

Observed Tmin (1975-2000)

predicted Tmin (2011-2040)



Month

Tm

in (d

eg. C

)


5

10

15

20

25

30

Predicted minimum temperature in three different time pe-riod (Patuakhali) CGCM3 A2 scenario

Observed Tmin (1975-2000)

Predicted Tmin (2011-2040)



Month

Tm

in (D

eg.C

)


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

5

10

15

20

25

Mean precipitation in different time period (Patuakhali)


Month

Mea

n pr

ecip

itatio

n (m

m/d

ay)

Increase of mean precipita-tion in monsoon period

Decrease of mean precipita-tion in post monsoon period

Precipitation Projections considering HadCM3 A2 Scenarios

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

2

4

6

8

10

12

14

16

18

20

Mean precipitation in different time period (patuakhali)


Month

Prec

ipita

tion

(mm

/day

) Increase of mean precipitation in post monsoon period

decrease of mean precipitation in monsoon period

decrease of mean pre-cipitation in pre monsoon period

Precipitation Projections considering CGCM3 A1B Scenarios

Precipitation change: For A2 scenario mean precipitation will

increase in monsoon period consecutive wet day will decrease that denotes rainfall intensity will increase. Decrease of precipitation in post monsoon season.

In A1B scenario mean precipitation will decrease in pre monsoon and monsoon period.

Conduct Climate Extreme analysis using Indices.

Complete Analysis of B2 scenarios

Generate Climate Projections for the Ganges Basin.

Future taks

g4: dr . saiful islam, iwfm, buet, bangladesh md. raqubul hasib , iwm, bangladesh

Documents

monsoon periodmaximum

post monsoon

premonsoon period

rate of temperature

fclimate projections

a1b scenariosmaximum

khulnamaximum increase

satkhiratemperature