Investigation and Prediction of Time Series of Temperature and Rainfall Variation in North-Eastern Region of Bangladesh By Ahmad Hasan Nury Advisor: Prof. Dr. rer. nat. Manfred Koch, Kassel University Dr. Md. Jahir Bin Alam, SUST, Bangladesh 1 Department of Geohydraulics and Engineering Hydrology, University of Kassel
24
Embed
Investigation and Prediction of Time Series of Temperature and Rainfall Variation in North-Eastern Region of Bangladesh By Ahmad Hasan Nury Advisor: Prof.
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
1
Investigation and Prediction of Time Series of Temperature and Rainfall Variation in North-Eastern
Region of Bangladesh
By
Ahmad Hasan Nury
Advisor:
Prof. Dr. rer. nat. Manfred Koch, Kassel University Dr. Md. Jahir Bin Alam, SUST, Bangladesh
Department of Geohydraulics and Engineering Hydrology, University of Kassel
2
Climate change is one of the biggest environmental threats to food production, water availability, forest biodiversity and livelihoods. It is widely believed that developing countries such as Bangladesh will be impacted more severely than developed countries (e.g. UK and USA).
According to F.HoVerhoog (1987) to estimate the impact of climatic change on the morphology of river basins, firstly estimation of the impact of climate change on precipitation and temperature variation analysis are necessary.
In this study, it is considered the region for the analysis where huge amount of rainfall occur in every year, which is Sylhet and Moulvibazar district. Every year there is great loss in rice production in this zone due to flood.
Introduction:
3
Scope of the study:
Time series graph
Statistical analysis:• Mean• Standard deviation• Mann-Kendall trend test
Rainfall frequency analysis
Short term prediction:• ARIMA (p d q) model
4
Study Area:
Sylhet division, the northeastern administrative division of Bangladesh, located at 24 053’ latitude and 91052’ longitudes.
The climate of Sylhet division is tropical monsoon with a predominantly hot and humid summer and a relatively cold winter.
Change in global climate rise of sea level may alter the productions in this area.
Figure: Study Area
5
Data Collection:
District Area (km2) Station ID TimeSylhet 3490.40 CL129
1981 to 2010(29 years)
CL 228Maulvibazar 2799.39 CL 104
CL126CL 229
District Area (km2) Type of data TimeSylhet 3490.40 Maximum
Temperature (0C) 1977 to 2011(34 years)
Minimum Temperature (0C)
Maulvibazar (Srimongal)
2799.39 Maximum Temperature (0C)Minimum Temperature (0C)
Table: Monthly Rainfall data (Source: Bangladesh Water Development Board)
Table: Monthly Temperature data (Source : Bangladesh Meteorological Department)
6
Jan-77
Jul-79Jan
-82Jul-8
4Jan
-87Jul-8
9Jan
-92Jul-9
4Jan
-97Jul-9
9Jan
-02Jul-0
4Jan
-07Jul-0
90
1020304050
f(x) = 0.000122989082941342 x + 29.3652542128739
Month
Temperature (0C)
Jan-77
Jul-79Jan
-82Jul-8
4Jan
-87Jul-8
9Jan
-92Jul-9
4Jan
-97Jul-9
9Jan
-02Jul-0
4Jan
-07Jul-0
90
10
20
30
f(x) = 0.000136483085416826 x + 12.6501660488277
Month
Temperature (0C)
Figure 1: Variation of monthly maximum temperature of sylhet. Figure 2: Variation of monthly minimum temperature of sylhet.
Jan-77
Jul-79Jan
-82Jul-8
4Jan
-87Jul-8
9Jan
-92Jul-9
4Jan
-97Jul-9
9Jan
-02Jul-0
4Jan
-07Jul-0
90
1020304050
f(x) = 6.57309827028196E-05 x + 31.4083679683943
Month
Temperature (0C)
Figure 3: Variation of monthly maximum temperature of Moulvibazar.
Jan-77
Jul-79Jan
-82Jul-8
4Jan
-87Jul-8
9Jan
-92Jul-9
4Jan
-97Jul-9
9Jan
-02Jul-0
4Jan
-07Jul-0
905
1015202530
f(x) = 0.00013112446456781 x + 11.2574278667069
Month
Temperature (0C)
Figure 4: Variation of monthly minimum temperature of Moulvibazar.
Data Analysis:
7
Jan-81
Mar-84
May-87
Jul-90
Sep-93
Nov-96Jan
-00
Mar-03
May-06
Jul-09
0500
10001500200025003000
f(x) = − 0.0171470680721389 x + 872.514662230674
Month
Rainfall (mm)
Jan-81
Mar-84
May-87
Jul-90
Sep-93
Nov-96Jan
-00
Mar-03
May-06
Jul-09
0
400
800
1200
1600
f(x) = 0.00334206828455125 x + 254.727585407721
Month
Rainfall (mm)
Figure 5: Variation of monthly Rainfall of sylhet station CL129. Figure 6: Variation of monthly Rainfall of sylhet station CL228.
Jan-81
Oct-83
Jul-86
Apr-89Jan
-92
Oct-94
Jul-97
Apr-00Jan
-03
Oct-05
Jul-08
0
400
800
1200
f(x) = − 0.00650528321579975 x + 500.433671088937
Month
Rainfall (mm)
Figure 7: Variation of monthly Rainfall of Moulvibazar station CL104.
Jan-81
Oct-83
Jul-86
Apr-89Jan
-92
Oct-94
Jul-97
Apr-00Jan
-03
Oct-05
Jul-08
0
400
800
1200
f(x) = − 0.00124939701280888 x + 260.326525346117
Month
Rainfall (mm)
Figure 8: Variation of monthly Rainfall of Moulvibazar station CL126.
Jan-81
May-83
Sep-85
Jan-88
May-90
Sep-92
Jan-95
May-97
Sep-99
Jan-02
May-04
Sep-06
Jan-09
0200400600800
10001200
f(x) = − 0.00313452195668542 x + 340.093583200547
Month
Rainfall (mm)
Figure 9: Variation of monthly Rainfall of Moulvibazar station CL229.
8
Month Mean (0C) Standard deviation (0C)January 28.72 2.736February 31.14 2.713
Figure 14: Rainfall frequency curve for Moulvibazar CL229
15
ARIMA (p,d,q) model:
•p order of autoregressive terms •d order of integrated term (non-seasonal differences; linear, quadratic, etc.) •q order of moving average (forecast errors)
Table 13: Parameter estimation for ARIMA (1 1 1) (1 1 1)12 model of monthly maximum temperature of sylhet
Data of temperature station for the period from 1977 to 2009 has been used for the calibration and from 2010 to 2011 has been used for the verification of the prediction.
Data of rainfall station for the period from 1981 to 2008 has been used for the calibration and from 2009 to 2010 has been used for the verification of the prediction.
19
Jan-10
Apr-10Jul-1
0
Oct-10Jan
-11
Apr-11Jul-1
1
Oct-11
05
10152025303540
Observed Max TemperaturePredicted Max Tempereture
Month
Temperature( 0C)
Figure 19: Comparison graph of Observed vs. Predicted values of the Monthly Maximum Temperature data of Sylhet Station.
Jan-10
Apr-10Jul-1
0
Oct-10
Jan-11
Apr-11Jul-1
1
Oct-11
05
1015202530
Observed min. Temperaturepredicted min temperature
Month
Temperature( 0C)
PBIAS = 0.18%
Figure 20: Comparison graph of Observed vs. Predicted values of the Monthly Minimum Temperature data of Sylhet Station.
PBIAS = - 0.33%
Jan-10
Apr-10Jul-1
0
Oct-10
Jan-11
Apr-11Jul-1
1
Oct-11
05
10152025303540
Observed Max TemperaturePredicted Max Tempereture
Month
Temperature( 0C)
PBIAS = 0.43%
Jan-10
Apr-10Jul-1
0
Oct-10
Jan-11
Apr-11Jul-1
1
Oct-11
0
5
10
15
20
25
30
Observed min. Temperaturepredicted min temperature
Month
Temperature( 0C)
Figure 21: Comparison graph of Observed vs. Predicted values of the Monthly Maximum Temperature data of Moulvibazar Station.
Figure 22: Comparison graph of Observed vs. Predicted values of the Monthly Minimum Temperature data of Moulvibazar Station.
PBIAS = - 0.53%
20
Jan-09
May-09
Sep-09
Jan-10
May-10
Sep-10
0100200300400500600700
Observed rainfall (mm)predicted rainfall (mm)
Month
Rainfall(mm)
PBIAS = 4.5%
Figure 23: Comparison graph of Observed vs. Predicted values of the Rainfall data of Sylhet Station CL129.
Jan-09
Apr-09Jul-0
9
Oct-09
Jan-10
Apr-10Jul-1
0
Oct-10
0200400600800
1000120014001600
Observed rainfall (mm)predicted rainfall (mm)
Month
Rainfall(mm)
PBIAS = - 1.07%
Figure 24: Comparison graph of Observed vs. Predicted values of the Rainfall data of Sylhet Station CL228.
Jan-09
May-09
Sep-09
Jan-10
May-10
Sep-10
0100200300400500600
Observed rainfall (mm)predicted rainfall (mm)
Month
Rainfall(mm)
Figure 25: Comparison graph of Observed vs. Predicted values of the Rainfall data of Moulvibazar Station CL104.
PBIAS = - 3.62%
Jan-09
Apr-09
Jul-09
Oct-09
Jan-10
Apr-10
Jul-10
Oct-10
0100200300400500600700800900
Observed rainfall (mm)predicted rainfall (mm)
Month
Rainfall(mm)
Figure 26: Comparison graph of Observed vs. Predicted values of the Rainfall data of Moulvibazar Station CL126.
PBIAS = - 6.56%
21
Jan-09
Apr-09
Jul-09
Oct-09
Jan-10
Apr-10
Jul-10
Oct-10
0
100
200
300
400
500
600
Observed rainfall (mm)predicted rainfall (mm)
Month
Rainfall(mm)
Figure 27: Comparison graph of Observed vs. Predicted values of the Rainfall data of Moulvibazar Station CL229.
PBIAS = - 1.89%
22
Conclusion:
The upward trend line and positive Mann-Kendall test statistics of time series of temperature (for the period between 1977 and 2011) indicates that both the monthly maximum and minimum temperature is increasing with time.
The downward trend line and negative Mann-Kendall test statistics of time series of rainfall (for the period between 1981 and 2010) indicates that monthly rainfall is decreasing with time except Sylhet station CL228 (almost upward trend line).
Mean temperature with their standard deviation indicates the variation of temperature in year to year is not very high.
Mean rainfall with their standard deviation indicates the variation of rainfall in year to year is high.
A best fitted curve has been drawn between return period and annual maximum rainfall for each rainfall station to see the frequency of it.
The fitness of ARIMA model for the temperature and rainfall is well. The temperature and rainfall time series fitted to ARIMA model for the selected stations can be used for estimating missing temperature and rainfall values, forecasting and investigating short term temperature and rainfall change.
23
References:
•F.HoVerhoog, the Influence of Climate Change and Climatic Variability on the Hydrologic Regime and Water Resources (Proceedings of the Vancouver Symposium, August 1987) IAHSPubl.no.168, 1987
•Ministry of Environment and Forests, Government of the People's Republic of Bangladesh(2008), Bangladesh Climate Change Strategy and Action Plan
•CEGIS & ADB (2009), Inception Report on Field Based Research on the Impacts of Climate Change on Bangladesh Rivers
•IWM (2005), Hydrological Impact Study of Tipaimukh Dam Project of India on Bangladesh
•UNFCC (2007), Climate Change: Impacts, Vulnerabilities and Adaptation In Developing Countries.
•Sarwar G. M. (2005), Impacts of Sea Level Rise on the Coastal Zone of Bangladesh, M.Sc. Thesis, Lund University International Masters Program in Environmental Science, Lund University, Sweden.
•Subramanya K, (2005), Engineering Hydrology, Tata McGraw-Hill Publishing Company Limited, New Delhi, India.