Correlation coefficients (CC) between various parameters of pre-monsoon season and monsoon rainfall were first studied. June, July, August and September rainfall Distribution of CC between March DBT and June, July, rainfall.
3.9.5(a-d): Correlation coefficient between monsoon rainfall and WBT of March, April and May and the correlation coefficient between pre-monsoon WBT and. 3.10.1(a-d): Multiple correlation coefficient between rainfall of June, July, August and September and the maximum temperature, minimum temperature, DBT and.
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3.10.2(a-d): Multiple correlation coefficient between rainfall in June, July, August and September and the maximum temperature, minimum temperature, DBT and. 3.10.3(a-d): Multiple correlation coefficient between the rainfall of June, July, August and September and the maximum temperature, minimum temperature, DBT and.
Introduction
Pre Monsoon
The pre-monsoon season is the transition period when the northerly or northwesterly winds of the winter season gradually change into the southerly or southwesterly winds of the summer monsoon or rainy season (June–September). During the early part of the pre-monsoon season, a narrow zone of air mass discontinuity lies over the entire country, extending from the southwestern part to the northeastern part.
Monsoon
Strengthening of the Asian monsoon is linked to the uplift of the Tibetan Plateau after the collision of India and Asia about 50 million years ago. With the arrival of the monsoon, the extreme temperatures of summer drop significantly across the country.
Dry Bulb Temperature (DBT)
Wet Bulb Temperature (WBT)
- Measurement of wet and dry bulb temperature
This means that the temperature of the wet bulb will be only slightly lower than the temperature of the dry bulb. This means that the wet bulb temperature will be much lower than the dry bulb temperature.
Rainfall
Oshawa et al., (2000) investigated the rainfall over Bangladesh during the 1995 summer monsoon season in terms of interseasonal variation of monsoon activities. Rainfall over Bangladesh is mainly dominated by the north-south oscillation of the monsoon trough.
Average
In this research work, we have used the DBT, WBT, minimum temperature, maximum temperature and rainfall of pre-monsoon season and rainfall of monsoon season for thirty meteorological stations across Bangladesh. The mathematical formulations used in this analysis are discussed in the following subsections.
Regression
- Regression Equations
These can be formally obtained by successively multiplying both sides of equation (2.2.2) by 1, X2, X3 and X4 and summing the two sides. These equations, which are equivalent to the normal equations (2.2.2), can be formally obtained by successively multiplying both sides of equation (2.2.3) by x2, x3 and x4 and adding the two sides.
Simple correlation
Multiple correlation
- Multiple correlation of 5 variables
Multiple correlation between rainfall in monsoon season (1) and DBT(2), WBT(3), MaxT(4) and MinT(5) in pre-monsoon season can be written as. In this way we can calculate rainfall in monsoon season and DBT for pre-monsoon season (712 ), rainfall in monsoon season and WBT in pre-monsoon season (r13 ), rainfall in monsoon season and MaxT for pre-monsoon season (r14 ), rainfall from monsoon season and MinT from the pre-monsoon season (r15 ), DBT and WBT from the pre-monsoon season (r23 ), DBT and MaxT from the pre-monsoon season (r24 ), DBT and MinT from the pre-monsoon season (r25 ), respectively.
1* CHAPTER III
Distribution of average DBT, WBT, MinT and MaxT of different months of Pre-Monsoon Season all over Bangladesh
- Distribution of average DBT of March, April and May
- Distribution of average WBT of March, April and May
- Distribution of average Minimum Temperature for the months of March-May In this section the average minimum temperature for the month of March to May
Then, the average WBT gradually increases from the northern to the southern part of the country. From the Sylhet and Teknaf regions, the average rainfall decreases towards the northern and western parts of the country.
Correlation coefficients (CC) between DBT of March, April and May and Rainfall of March, April and May
- Distribution of the CC between DBT of March and rainfall of March, April and May The distribution of CC between the DBT of March and the rainfall of March is
- Distribution of the CC between average Pre-monsoon DBT and average rainfall of March, April and May
- Distribution of the CC between Pre-monsoon rainfall and DBT of March, April and May and the CC between Pre-monsoon DBT and Pre-monsoon rainfall
The distribution of CC between the DBT of April and the rainfall of May is shown in Fig 3.2.2(c). The distribution of CC between the DBT of May and the rainfall of April is shown in Fig 3.2.3(b). The distribution of CC between the pre-monsoon DBT and the rainfall of May is shown in Fig 3.2.4(c).
The distribution of CC between the DBT in April and the pre-monsoon rainfall is shown in Fig. 3.2.5(b). The distribution of CC between the DBT in May and the pre-monsoon rainfall is shown in Fig. 3.2.5(c).
Correlation Coefficients between Minimum Temperature of March-May and Rainfall of March-May
- Distribution of the CC between Minimum Temperature of March and rainfall of March, April and May
- Distribution of the CC between Minimum Temperature of April and rainfall of March, April and May
- Distribution of the CC between Pre-monsoon minimum temperature and rainfall of March, April and May
- Distribution of the CC between average Pre-monsoon rainfall and minimum temperature of March, April and May and pre-monsoon season itself
The distribution of CC between the minimum temperature in April and the amount of precipitation in April is shown in Figure 3.3.2(b). The distribution of CC between the lowest temperature in April and the amount of precipitation in May is shown in Figure 3.3.2(c). The distribution of CC between the lowest temperature in May and the amount of precipitation in March is shown in Figure 3.3.3(a).
The distribution of CC between the minimum temperature in May and the precipitation in April is shown in Fig. 3.3.3(b). The distribution of CC between the minimum temperature in May and the precipitation in May is shown in Fig. 3.3.3(c).
Correlation coefficients between Maximum Temperature (MaxT) of March- May and Rainfall of March-May
- Distribution of the CC between MaxT of March and rainfall of March, April and May
- Distribution of CC between MaxT of April and rainfall of March, April and May The distribution of CC between the MaxT of April and the rainfall of March is
- Distribution of the CC between MaxT of May and rainfall of March, April and May The distribution of CC between the MaxT of May and the rainfall of March is
- Distribution of the CC between Pre-monsoon MaxT and rainfall of March, April and May
- Distribution of the CC between Pre-monsoon rainfall and MaxT of March, April and May and pre-monsoon season itself
The distribution of CC between the MaxT of May and the rainfall of April is The figure shows that the distribution of CC is positive at some southern, southwestern part of the country. From the distribution pattern we see that the CC is negative across the country except Feni, Satkhira, Barisal and Khepupara.
The figure shows that CC distribution is negative across the country except in Feni, Khepupara, Sandwip and Chittagong. The distribution of CC between MaxT in May and pre-monsoon rain is shown in Figure 3.4.5(c).
Correlation coefficients between WBT of March-May and Rainfall of March- May
- Distribution of the CC between WBT of March and rainfall of March, April and May
- Distribution of the CC between WBT of April and rainfall of March, April and May The distribution of CC between the WBT of April and the rainfall of March is
- Distribution of CC between Pre-monsoon WBT and rainfall of March, April and May
- Distribution of the CC between average Pre-monsoon rainfall and WBT of March, April and May and the Pre-monsoon season itself
The figure shows that the distribution of CC is positive at Ishwardi-Bogra-Mymensing-Sylhet belt. The maximum positive and negative CC are observed at Patuakhali and Sitakundu and are 0.38 and -0.38 respectively. The figure shows that the distribution of CC is positive in the entire northern and northwestern part of the country except Dinajpur and Rangpur.
The maximum positive and negative CC are observed at Satkhira and Sitakundu and are 0.46 and -0.50 respectively. The maximum positive and negative CC are observed at Satkhira and Madaripur and are 0.37 and -0.52 respectively.
Correlation coefficients between DBT of March, April and May and Rainfall of June, July, August and September
- Distribution of CC between DBT of March and average rainfall of June, July, August and September
- Distribution of CC between DBT of April and rainfall of June, July, August and September
- Distribution of CC between DBT of May and rainfall of June, July, August and September
The figure shows that the distribution of CC is positive throughout the central, northern and western parts of the country. The figure shows that the distribution of CC is positive in the north-west, east and south of the country. The figure shows that the distribution of CC is positive at Srimongal-Mymensing - Tangail - Bogra - Rangpur belt.
The figure shows that the distribution of CC is positive in the Bogra-Ishwardi-Dhaka-Mymensing-Srimongal belt. This figure shows that the spread of CC is positive from the central part to the southern and northeastern part of the country.
Correlation Coefficients between Minimum Temperature (MinT) of March-May and Rainfall of June-September
- Distribution of CC between MinT of March and rainfall of June, July, August and September
- Distribution of the CC between DBT of April and rainfall of June, July, August and September
- Distribution of the CC between MinT of May and rainfall of June, July, August and September
- Distribution of CC between monsoon rainfall and MinT of March, April and May and Pre-monsoon season itself
The CC is positive in the extreme south and southwest of the country. The figure shows that the spread of CC is positive in the northwest, southwest and center of the country. The maximum value of CC is observed at Maizdy Court, which is 0.28 with a significance of 95%.
The negative CC is observed in the western, southwestern and eastern parts of the country. The figure shows that the spread of CC is positive towards the southern, southwestern and southeastern parts of the country and towards Syihet.
Correlation coefficients between Maximum Temperature of March-May and Rainfall of June-September
- Distribution of the CC between MaxT of March and rainfall of June, July, August and September
- Distribution of the CC between MaxT of April and rainfall of June, July, August and September
- Distribution of the CC between MaxT of May and rainfall of June, July, August and September
- Distribution of the CC between Pre-monsoon MaxT and rainfall of June, July, August and September
The figure shows that the CC distribution is positive in most regions of the country. KZ is negative in the northwestern and northeastern parts of the country. The figure shows that CC distribution is positive in Ishwardi-Jessore-Satkhira-Khulna belt.
The figure shows that CC distribution is positive in Ishwardi-Madaripur-Jessore-Chandpur belt. The figure shows that CC distribution is positive in the northern part of the country except Rajshahi.
Correlation coefficients between WBT of March-May and Rainfall of June- September
- Distribution of the CC between WBT of March and rainfall of June-September The distribution of CC between the WBT of March and the rainfall of June is
- Distribution of the CC between WBT of April and rainfall of June-September The distribution of CC between the WBT of April and the rainfall of June is shown
- Distribution of the CC between WBT of May and rainfall of June-September
- Distribution of the CC between Pre-monsoon WBT and rainfall of June-September The distribution of CC between the average pre-monsoon WBT and the rainfall of
- Distribution of the CC between average monsoon rainfall and WBT of March-May and Pre-monsoon season itself
The figure shows that CC distribution is positive in all places in Bangladesh except Mymensingh and southern region. The figure shows that the distribution of CC is negative throughout the northern and eastern regions of the country. It can be seen from the figure that the CC distribution is positive everywhere, except in the southern and southeastern parts of the country.
KZ is negative in the eastern, central and extreme southern part of the country. The distribution of CC between pre-monsoon WBT and monsoon rains is shown in Figure 3.9.5(d). The distribution of CC is positive in the extreme northern part of Bangladesh, while it is negative in the northwestern and northeastern parts of Bangladesh. part of the country.
Multiple Correlation Coefficients (MCC) between Rainfall of Monsoon and 4 parameters of Pre-Monsoon
- Distribution of the MCC between Rainfall of different months of Monsoon and DBT, WBT, MinT and MaxT of March
The distribution of MCC between the rainfall of June and the DBT, maximum temperature, minimum temperature and WBT of April is shown in Fig 3.10.2(a). From the distribution pattern, we see that the MCC is positive across the country. The distribution of MCC between the rainfall of June and the DBT, maximum temperature, minimum temperature and WBT of May is shown in Fig 3.10.3(a).
From the t-distribution pattern we see that the MCC is positive across the country. The distribution of the MCC between September rainfall and May DBT, maximum temperature, minimum temperature and WBT is shown in Figure 3.10.3(d).
CONCLUSIONS
The average DBT of the pre-monsoon season increases gradually from the northeastern to the southeastern part of the country. 40, • The average WBT of the pre-monsoon season is found to be minimum in the northern part of the country and gradually increases towards the south. The maximum amount of average rainfall is observed on the eastern side of the country and gradually decreases towards the west during the pre-monsoon and monsoon seasons.
The correlation coefficient between pre-monsoon WBT and pre-monsoon rain is positive mostly in the central part and towards the north-east and north-west of the country, especially in the Ishwardi-Bogra-Mymensing area. The correlation coefficient between pre-monsoon WBT and monsoon rainfall was found to be positive mainly in the southern, southwestern and extreme northern (mainly Rangpur-Dinajpur-Bogra area) parts of the country.
A., 2002: Correlation between winter temperature and monsoon rainfall over Bangladesh, presented at the Biennial Symposium on Physics and Modern Development, Dhaka, Bangladesh, March 30-31. A., 2004: Correlation between winter temperature and post-monsoon rainfall over Bangladesh, presented at the International Conference on Physics for Understanding and Applications, Dhaka, Bangladesh, February 22-24. R., 1978: On four shaded south-west monsoon rains over India with mid-tropospheric circulation anomaly in April, Indian Journal of Met.
R., 1994: Regression forecasting of monsoon rainfall in Bangladesh, Paper presented in the seminar on Monsoon Dynamics held at the German Cultural Center Dhaka, Bangladesh, 1 November 1994. Mahbub, A., 2002: Correlation between winter temperature and monsoon rainfall over Bangladesh, paper presented in 2.
