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
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec0
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
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec0
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
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec0
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)
Forcasted Tmax (2041-2070)
Forcasted Tmax (2071-2099)
Month
Tem
pera
ture
(Deg
. C)
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec0
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)
forcasted Tmax (2041-2070)
forcasted Tmax (2071-2100)
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)
Base period (1961-1990)Period A (2011-2040)Period B (2041-2070)Period C (2071-2099)
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)
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec0
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)
Predicted Tmax (2071-2099)
Month
Tem
pera
ture
(deg
.C)
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec0
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)
Predicted Tmax (2011-2040)
Predicted Tmax (2041-2070)
Predicted Tmax (2071-2100)
Month
Tm
ax (D
eg.C
)
Maximum Increase of in monsoon period
Maximum Increase in Pre monsoon period
Maximum Temperature Projections considering A2 and A1B Scenarios
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)
Base period (1961-1990)Period A (2011-2040)Period B (2041-2070)Period C (2071-2099)
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)
Base period (1961-1990)Period A (2011-2040)Period B (2041-2070)Period C (2071-2099)
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)
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec0
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)
predicted Tmin (2041-2070)
predicted Tmin (2071-2099)
Month
Tm
in (d
eg. C
)
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec0
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)
Predicted Tmin (2041-2070)
Predicted Tmin (2071-2100)
Month
Tm
in (D
eg.C
)
Maximum Temperature Projections considering A2 and A1B Scenarios
1 2 3 4 5 6 7 8 9 10 11 120
5
10
15
20
25
Mean precipitation in different time period (Patuakhali)
Base period (1975-2000)Period A (2011-2040)Period B (2041-2070)Period C (2071-2099)
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)
Base period (1975-2000)Period A (2011-2040)Period B (2041-2070)Period C (2071-2099)
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
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