Analyzing changes of temperature over Bangladesh due to global warming using historic data

Dr. A.K.M. Saiful Islam

Associate ProfessorBangladesh university of engineering and technology

Email: akmsaifulislam@iwfm.buet.ac.bd

Introduction Intergovernmental Panel on Climate

Change (IPCC) has reported in their fourth assessment report that global surface temperature increased 0.74 ± 0.18 °C during the 100 years ending in 2005.

In this context, long term changes of near surface air temperature over Bangladesh have been studied using the available historic data collected by the Bangladesh Meteorological Department (BMD).

Data

Maximum and minimum daily temperature data of last sixty years (1948-2007) collected from 34 stations of BMD located all over the Bangladesh have been used in this study.

Trend analysis has been conducted on monthly data for all the stations

Study Area

Trend Analysis

y = 0.0063x + 17.855

29.4

29.6

29.8

30

30.2

30.4

30.6

30.8

31

31.2

31.4

1948

1951

1954

1957

1960

1963

1966

1969

1972

1975

1978

1981

1984

1987

1990

1993

1996

1999

2002

2005

2008

Trends of Maximum Temperature

Increase 0.63 0C on 100 years scale

Trends of Minimum Temp

y = 0.0137x - 6.0268

20

20.2

20.4

20.6

20.8

21

21.2

21.4

21.6

21.8

22

1948

1951

1954

1957

1960

1963

1966

1969

1972

1975

1978

1981

1984

1987

1990

1993

1996

1999

2002

2005

2008

Trends of Minimum Temperature

Increase 1.37 0C on 100 years scale

ID Station Latitude Longitude Altitude Max. Temp. (0C per yr.) Min. Temp. (0C per yr.)

11704 Barisal 22.72 90.37 2.1 m 0.0077 -0.0163

11706 Bhola 22.68 90.65 4.3 m 0.0170 0.0206

10408 Bogra 24.85 89.37 17.9 m 0.0117 0.0404

11316 Chandpur 23.23 90.7 4.9 m 0.0163 0.0161

11921 Chittagong 22.35 91.82 33.2 m 0.0224 0.009

41926 Chuadanga 23.65 88.82 11.6 m -0.0038 0.0217

11313 Comilla 23.43 91.18 9 m 0.0049 -0.0009

11927 Cox's Bazar 21.45 91.97 2.1 m 0.0295 0.022

11111 Dhaka 23.78 90.38 6.5 m 0.0119 0.0225

10120 Dinajpur 25.65 88.68 37.6 m -0.0213 0.0151

11505 Faridpur 23.93 89.85 8.1 m 0.0275   --

11805 Feni 23.03 91.42 6.4 m 0.0174 0.0331

11814 Hatiya 22.45 91.1 2.4 m 0.0261 -0.0202

10910 Ishardi 24.15 89.03 12.9 m 0.0032 0.0037

11407 Jessore 23.2 89.33 6 m 0.0147 0.0113

12110 Khepupara 21.98 90.23 1.8 m 0.0266 0.0037

11604 Khulna 22.78 89.53 2.1 m 0.0037 -0.0053

11925 Kutubdia 21.82 91.85 2.7 m 0.0416 0.0248

11513 Madaripur 23.17 90.18 7 m 0.0047    --

11809 Maijdicourt 22.87 91.1 4.9 m 0.0193 0.0204

41958 Mongla 22.47 89.6 1.8 m 0.0430 0.0104

10609 Mymensing 24.73 90.42 18 m -0.0086 0.0086

12103 Patuakhali 22.33 90.33 1.5 m 0.0328 0.026

10320 Rajshahi 24.37 88.7 19.5 m 0.0110 0.0027

12007 Rangamati 22.63 92.15 68.9 m -0.0039 -0.0178

10208 Rangpur 25.73 89.27 32.6 m -0.0259 0.0281

11916 Sandwip 22.48 91.43 2 m 0.0074 -0.0182

11610 Satkhira 22.72 89.08 4 m 0.0065 0.0107

41858 Sayedpur 25.75 88.92 39.6 m 0.0266    --

11912 Sitakunda 22.63 91.7 7.3 m 0.0581 -0.0212

10724 Srimangal 24.3 91.73 22 m 0.0030 0.0237

10705 Sylhet 24.9 91.88 33.5 m    -- 0.0057

41909 Tangail 24.25 89.93 10.2 m 0.0174 -0.0234

11929 Teknaf 20.87 92.3 5 m 0.0242 0.0236

Trends of TemperatureFor 34 ground measuring Stations of BMD

Trends of Maximum Temp.

Trends of Minimum Temp.

Maximum TemperatureMaximum increase: 0.0581 at ShitakundaMinimum increase: -0.026 at Rangpur

Minimum TemperatureMaximum increase: 0.0404 at BograMinimum increase: -0.023 at Tangail

Monthly temperature over Bangladesh (1948-2007)

10

15

20

25

30

35

Janu

ary

Feb

ruar

y

Mar

ch

Apr

il

May

June

July

Aug

ust

Sep

tem

ber

Oct

ober

Nov

embe

r

Dec

embe

r

Tem

pera

ture

(0C

)

minimum

maximum

Month-wise Trends

Month Max. Temp.(0C per yr.)

Min. Temp.(0C per yr.)

January -0.0142 0.0104

February 0.0000 0.0340

March -0.0117 0.0220

April -0.0142 0.0121

May 0.0010 0.0052

June 0.0139 0.0103

July 0.0116 0.0075

August 0.0183 0.0081

September 0.0070 0.0031

October 0.0178 0.0078

November 0.0270 0.0289

December 0.0147 0.0270

Trends of minimum temp. in January

y = 0.0104x - 8.2864

10

10.5

11

11.5

12

12.5

13

13.5

14

1948

1951

1954

1957

1960

1963

1966

1969

1972

1975

1978

1981

1984

1987

1990

1993

1996

1999

2002

2005

2008

Trends of Minimum Temperature

Increase 1.04 0C in 100 years

Trends of minimum temp. in February

y = 0.0352x - 54.638

10

11

12

13

14

15

16

17

18

19

194

8

195

1

195

4

195

7

196

0

196

3

196

6

196

9

197

2

197

5

197

8

198

1

198

4

198

7

199

0

199

3

199

6

199

9

200

2

200

5

200

8

Trends of Minimum Temperature

Increase 3.5 0C in 100 years

Average Temperature in January (1948-2007)

Daily Maximum Daily Minimum

Effect of Temperature rise on Agriculture

In winter season (Nov-Feb), the main crops of Bangladesh are: Boro (rice), Wheat, Potato, vegetables.

Increase of winter temperature can reduce the environmental suitability for wheat, potato and other temperate crops grown in Rabi season.

It might benefit Boro paddy and kharif crops.

Wheat growing areas and minimum temperature trend map in January

Trends of minimum temp Wheat coverage area

Effect on Potato: Temperature derived from MODIS data during January, 2006

15

17

19

21

23

25

27

3

11 19 27 32 40 48 56 64 72 80 88 96

104

days after plantation

Mea

n T

emp

(d

eg C

)

0.5

0.7

0.9

1.1

1.3

1.5

1.7

veg

etat

ion

in

dex

Temperature

fPAR

NDVILAI

Potato Field in Munshigonj

Plantation starts on December

Temperature map in January

Presently working We are presently working on the future

prediction of temperature trends using PRECIS regional climate change model.

Climate Change Study Cell has been formed in our university with vision of “to to establish itself as the premier knowledge establish itself as the premier knowledge center on climate change risk and center on climate change risk and adaptation for Bangladesh”.adaptation for Bangladesh”.

http://teacher.buet.ac.bd/diriwfm/climate/

Conclusion

Both daily minimum and maximum temperature shows positive trends over Bangladesh. Increase of daily maximum temp. is 0.63 0C and daily minimum temp is 1.37 0C in 100 years.

Maximum increase of daily maximum temp. has occurred in November at 2.7 0C and daily minimum temp. has occurred in February at 3.4 0C in 100 years.

Maximum increase of daily maximum temp. has occurred as 5.810C at Shitakunda and daily minimum temp. has occurred as 5.04 0C at Bogra in 100 years.

Increase of winter temperature can reduce the environmental suitability for wheat, potato and other temperate crops grown in Rabi season.

Thank you