In addition to radio and television, daily newspapers publish weather reports regularly on the basis of information supplied by the meteorological department. Atmospheric pressure and winds These are characterised by seasonal reversals between summer and winter in Bangladesh. The amount of rainfall in this season varies from about 20 cm in the west central part to slightly over 80 cm in the northeast. 0000004360 00000 n Annual Weather Averages Near Dhaka. According to some analysts, the effects of increased temperature will have both destructive and beneficial consequences - destructive to some areas and beneficial to other areas. It is surrounded by the Assam Hills in the east, the Meghalaya Plateau in the north, the lofty Himalayas lying farther to the north. Climatic stations are scattered around the country - to record the diverse geographic conditions of the country. 0000012029 00000 n The groundwater, however, provides adequate storage to compensate for annual variations in rainfall and stream flow. The month of March may also be considered as the spring season, and the period from mid-October through mid-November may be called the autumn season. Bangladesh Historical Precipitation Monitoring. These account for 70% of the annual total in the eastern part, 80% in the southwest, and slightly over 85% in the northwestern part of Bangladesh. ËD$NÈWi. The least humid months in the eastern areas are January to March. 0000004192 00000 n The mean rainfall during the monsoon season ranges from 1000 mm to 3000 mm in the country. The maximum amount of rainfall has been recorded in the northern part of Sylhet district and in the southeastern part of the country (Cox's Bazar and Bandarban districts). S.B. Rainfall intensity using IMD yields larger value than those obtained by Hershfield method. The most striking feature of its climate is the reversal of the wind circulation between summer and winter, which is an integral part of the circulation … The monsoon is less intense in the west, where the annual rainfall is around 1,500/1,600 mm (60/63 in), with a maximum in July of about 300/350 mm (12/13.5 … 0000002756 00000 n IDF curve was developed for North-East region of Bangladesh and also found that the rainfall data in this region follow Gumbel‟s Extreme Value Distribution [4]. Weather bulletins and forecasting by the Bangladesh Meteorological Department for 6-hour, 12-hour and 24-hour periods are broadcast on radio and television. 0000001136 00000 n Sylhet is the areas in Bangladesh where maximum rainfall occur. If this trend continues, then it will reach 450 ppmV by the year 2050. developed to estimate near real-time rainfall in Bangladesh using satellite data. Winter (November … Actually climatic changes on a global scale do not occur overnight; in fact, they occur only over a time scale of thousands of years. Generalized Rainfall Intensity-Duration Frequency … Bangladesh is located in the tropical monsoon region and its climate is characterised by high temperature, heavy rainfall, often excessive humidity, and fairly marked seasonal variations. 0000063253 00000 n After the withdrawal of the summer monsoon, the cloud cover decreases rapidly, dropping to 25% in the northern and western parts, and 40-50% in the southern and eastern parts. Heavy rainfall is characteristic of Bangladesh causing it to flood every year. Average temperatures in January vary from about 17'C in the northwestern and northeastern parts to 20°-21°C in the coastal areas. Dhaka, Bangladesh - Hourly past weather, almanac for Dhaka including historical temperature, wind, rain, pressure and humidity stats | WorldWeatherOnline.com Realtime weather, 14 day weather forecast, historical weather at … Weather report Bangladesh Meteorological Department prepares the weather reports of the country. It has been estimated by some scientists that the concentration of CO2 in the atmosphere during the pre-industrial period was 285-290 ppmV (parts per million by volume). 0000001693 00000 n It is generally claimed that the temperature of the earth has been increasing since the beginning of the 20th century. On an average, the cloud cover in this season is about 10% almost all over the country. 0000005555 00000 n 0000008496 00000 n During an impending cyclone, observation and forecasting are made and warnings issued almost continuously through radio and television. Bangladesh extends from 20°34'N to 26°38'N latitude and from 88°01'E to 92°41'E longitude. Daily Rainfall Data 1007. Climatic change Any climatic change in Bangladesh will, of course, be a part of worldwide climatic changes. Normal Monthly Rainfall; Normal Monthly Rainy Day; Daily Normal Rainfall; Daily Normal Maximum Temperature; Daily Normal Minimum Temperature; Temperature Data; Extreme Rainfall; Publications. Here the lowest monthly average of 58.5% has been recorded at Brahmanbaria in March. Climate change will increase around 5% of the country's rainfall by 2030 (Su et al., 2006) and small changes in mean and standard deviation will largely impact on rainfall intensity. Except the hilly southeast, most of the country is a low-lying plainland. Unusual rainfall and long lasting rainy season is a great factor to take account into. Most of the earlier studies concerning the PCI have been carried … However, the cold winter air that moves into the country from the northwestern part of India loses much of its intensity by the time it reaches the northwestern corner of the country. In July, rainfall amounts to 800 mm (31.5 in) in Sylhet, to 750 mm (29.5 in) in Chittagong, to 900 mm (35.5 in) in Cox's Bazar, and to as high as 1,000 mm (40 in) in Teknaf. However, it is more extensive in the southern and eastern parts (90%) than in the northwestern part (75%). As a result, a stream of warm and moist air from the Bay of Bengal flows toward the above-mentioned low pressure through Bangladesh (similar flow prevails from the Arabian Sea toward India). At present, the rain-gauges over Bangladesh are the only tool by which to measure rainfall, so Although few studies have reported intensity and rainfall circulation in various regions (Shahid, 2010; Rahman et al., 2016; Zannat et al., 2019) and long-range variations in precipitation across Bangladesh (Ahmed et al., 2017; Burkart and Kinney, 2016). The average relative humidity for the whole year ranges from 78.1% at Cox's Bazar to 70.5% at Pabna. January, the same as December, is a moderately hot winter month in Dhaka, Bangladesh, with average temperature fluctuating between 12.7°C (54.9°F) and 25.4°C (77.7°F).January is the coldest month, with an average high-temperature of 25.4°C (77.7°F) and an average low-temperature of 12.7°C (54.9°F). 0000004805 00000 n The average annual rainfall at Bangladesh varies from a maximum of 5,690 mm in the northeast of the country to minimum of 1,110 mm in the west. Based on weather reports collected during 2005–2015. The rainfall in Bangladesh varies, depending upon season and location. Rainfall in this season is caused by the tropical Depressions that enter the country from the Bay of Bengal. In that case, all low coastal plains and delta areas around the world will be submerged - thereby reducing the area of fertile agricultural lands and food production, and increasing food shortage, hunger, poverty and human misery on a global scale. xref Averages are for Rajshahi, which is 6 miles from Rajshahi. The maximum rainfall occurs at Sylhet in the north-eastern part and along the coastline in the southern part and with a minimum in … The pre-monsoon hot season is characterised by high temperatures and the occurrence of thunderstorms. Rainfall Intensity: the average daily precipitation over the season considering only wet days. The winter season is very dry, and accounts for only 2%-4% of the total annual rainfall. Temperature January is the coldest month in Bangladesh. 0000003258 00000 n On the other hand, during the summer season, a centre of low pressure develops over the west-central part of India because of intense surface heat. This wind is the part of the winter monsoon circulation of the South Asian subcontinent. Temperature of the earth has increased by 0.3-1°C since the beginning of the 20th century as a consequence of increased CO2 in the atmosphere. Daily Rainfall Data . As a consequence, it is estimated that the sea level will rise 2-3 metres by the year 2050. 0000007479 00000 n 240 0 obj<>stream 0000009549 00000 n In some places in Rajshahi and Kushtia districts the maximum temperature in summer season rises up to 40°C or more. 0000013069 00000 n 0000011030 00000 n Only few researches have been carried out so far on rainfall characteristics of Dhaka and Bangladesh. In this paper, differences in rain intensity in and around Bangladesh during various rainy periods are described. However, there is another side to the argument. 0000003527 00000 n Rainfall Table; Water Level Table; Forecast & Warning . Dry Period Bulletin; Extended Range (1-15 Days) Flow Forecast (Experimental ) Special Outlook; Map. Average precipitation (rainfall, snow) in millimeter per month in Dhaka, Bangladesh displayed in a beautiful overview. 238 0 obj<> endobj The pre-monsoon season is the transition period when the northerly or northwesterly winds of the winter season gradually changes to the southerly or southwesterly winds of the summer monsoon or rainy season (June-September). 0000010875 00000 n Moreover, there will be differential temperature increase in summer and winter - temperature increase in the winter season will be higher than that in the summer. 0000063716 00000 n 0000000016 00000 n 0000009777 00000 n Rainfall water that is condensed from the aqueous vapour in the atmosphere and falls in drops from the sky to the earth is called rain; and the total amount of rain that falls in a particular area within a certain time is called rainfall. Except for the relatively dry western region of Rajshahi, where the annual rainfall is about 1,600 mm (63.0 in), most parts of the country receive at least 2,300 mm (90.6 in) of rainfall per year. As a result of the flow of cold-dry winds from the northwestern part of India during the winter season, the cloud cover is at a minimum. The average temperature in Dhaka is 25.9 °C | 78.6 °F. This wind is the part of the summer monsoon circulation of the sub-continent. Bibliography Rafique Ahmed, Abhaoa O Jalabayu Vijnan (Meteorology and Climatology, written in Bangla), MS Alam, Department of Geography and Environmental Studies, University of Rajshahi, Bangladesh, 1997; RG Barry and RJ Chorley, Atmosphere, Weather and Climate, Routledge, London and New York, 1998. http://en.banglapedia.org/index.php?title=Climate&oldid=16046. This page was last modified on 2 December 2014, at 16:41. Go to resource. Find the best time to go to Dhaka. During the winter season, a centre of high pressure lies over the northwestern part of India. 0000036617 00000 n Computer simulation of global temperature change shows that if the CO2 concentration of the atmosphere becomes doubled from its present-day value, then global temperature would increase 1.3°-4°C. The summers here have a good deal of rainfall, while the winters have very little. Average rainy days during the season vary from 60 in the west-central part to 95 days in the southeastern and over 100 days in the northeastern part. To its south lies the bay of bengal, and to the west lie the plainland of west bengal and the vast tract of the Gangetic Plain. The average annual rainfall varies from a maximum of 5,690 mm in the northeast of the country to minimum of 1,110 mm in the west. Precipitation in Bangladesh averaged 202.39 mm from 1901 until 2015, reaching an all time high of 1005.33 mm in September of 1934 and a record low of 0.01 mm in December of 1993. Academia.edu is a platform for academics to share research papers. As this season progresses, this discontinuity weakens and retreats toward northwest, and finally disappears by the end of the season, making room for the onset of the summer monsoon. There are four main seasons: the pre-monsoon (March-May), which has the highest temperatures and experiences the maximum intensity of cyclonic Scarcity or heavy - both rainfall effects rural and urban life to a great extent with the changing pattern of the climate. Observation and interpretation of satellite and radar imageries are important for prediction of severe weather and cyclones. curves, which give a plot of rainfall intensity versus rainfall duration and recurrence interval. After the month of April, the temperature dampens due to increased cloud cover. Short duration The additional uplifting (by the Meghalaya Plateau) of the moist air causes higher amount of rainfall in the northeast. The rainy season, which coincides with the summer monsoon, is characterised by southerly or southwesterly winds, very high humidity, heavy rainfall, and long consecutive days of rainfall which are separated by short spells of dry days. 2. Widespread cloud covers causes dampening of temperature during the later part of the pre-monsoon season. However, wind directions during the transition seasons (in spring and autumn) are variable. Rainfall The single most dominant element of the climate of Bangladesh is the rainfall. Geographic distribution of annual rainfall shows a variation from 150 cm in the west-central part of the country to more than 400 cm in the northeastern and southeastern parts. The amount of rainfall in this season varies from 100 cm in the west central part to over 200 cm in the south and northeast. 0000004948 00000 n Bangladesh is located in the tropical monsoon region and its climate is characterised by high temperature, heavy rainfall, often excessive humidity, and fairly marked seasonal variations. Rainfall. Because of the country's location in the tropical monsoon region, the amount of rainfall is very high. [Rafique Ahmed]. 0000066386 00000 n The result of the analysis, combined with the observation of upper air, satellite imagery and radar imagery (collected in Dhaka) are used for weather forecasting. Rainfall during this season varies from less than 2 cm in the west and south to slightly over 4 cm in the northeast. 0000014915 00000 n During the early part of the pre-monsoon season, a narrow zone of air mass discontinuity lies across the country that extends from the southwestern part to the northeastern part. Climate Report; Report on Roanu; Report on MORA; Newsletter. %%EOF With the progression of the season, the cloud cover increases, reaching 50-60% by the end of the pre-monsoon hot season. Bangladesh occupies an area of 1, 47,570 square Kilometers, has a sub-tropical monsoon climate characterized by wide seasonal variations in rainfall, moderately warm … 0000002459 00000 n 0000063522 00000 n 0000037077 00000 n The department is responsible for observation, recording, operation and maintenance of weather stations and weather instruments, and for reporting of daily/weekly weather information to the public. REFERENCES Bell F. C.1969. During the early part of this season, the winds are neither strong nor persistent. The Köppen-Geiger climate classification is Aw. Observed concentration of CO2 in the atmosphere at the Muana Loa Observatory in Hawaii shows an increasing trend, from 315 ppmV in 1958 to 352 ppmV in 1988. Clouds In Bangladesh, the cloud cover has two opposing seasonal patterns, coinciding with the winter monsoon and the summer monsoon. The most striking feature of its climate is the reversal of the wind circulation between summer and winter, which is an integral part of the circulation system of the South Asian subcontinent. Precipitation in Bangladesh increased to 5.94 mm in December from 5.07 mm in November of 2015. An average annual rainfall of 5000mm have recorded till now. The average annual discharge from … During the summer monsoon season, which is also the rainy season, the cloud cover is very widespread. In the present climate, annual precipitation over the domain ranges from 500 mm (Tibet) to 2500 mm (Bangladesh). Environment. The overall objective of this paper is to assess the present trend of high intensity rainfall and compare it with the predicted future trend and gather information on the effect of climate change on rainfall pattern and intensity. Climatic stations Bangladesh Meteorological Department is responsible for observation, recording and archiving of climatic data for various stations in the country. 238 42 Humidity March and April are the least humid months over most of the western part of the country. Averages are for Dhaka, which is 4 miles from Dhaka. CLIMATE OF BANGLADESH . This page has been accessed 36,907 times. Rainfall Distribution Map; Inundation Map. Rainfall prediction is very important for the Bangladesh economy and day to day life. Rainfall at station above 50 millimeters are shown in red.red. Bangladesh : Rainfall & Weather. Bangladesh receives rain and cloud when some powerful western disturbance approaches from Mediterranean Sea crossing Iran , Pakistan , Northern India and then in Bangladesh . More than 70% of Bangladesh's annual rainfall occurs in the monsoon (June- September) season. April is the hottest month when mean temperatures range from 27°C in the east and south to 31°C in the west-central part of the country. This narrow zone of discontinuity lies between the hot dry air coming from the upper Gangetic plain and the warm moist air coming from the Bay of Bengal. Global warming will cause the polar ice caps and Himalayan ice caps to melt at a slow pace. Saiful Islam, M. Shah Alam Khan, Impact of climate change on rainfall intensity in Bangladesh, in 3rd International Conference on Water and Flood Management, ICWFM, 2011 Google Scholar During this season, wind inside the country generally have a northerly component (flowing from north or northwest). Now a day, erratic rainfall becomes very common in Bangladesh. 0000005087 00000 n The details of data are analysed, interpreted and mapped here. Rainfall during this season accounts for 10%-25% of the total annual rainfall which is caused by the thunderstorms or nor’wester (locally called Kalbaixakhi [Kalbaishakhi]). 0 The major climatic stations from which long-term climatic data are available are - Barisal, Bhola, Bogra, Chittagong, Comilla, Cox's Bazar, Dhaka, Dinajpur, Faridpur, Feni, Hatiya, Ishwardi, Jessore, Khepupara, Khulna, Kutubdia, Madaripur, Maijdi Court, Mymensingh, Patuakhali, Rajshahi, Rangamati, Rangpur, Saidpur, Sandwip, Sitakunda, Sreemangal, Sylhet and Teknaf. In late December and early January, minimum temperature in the extreme northwestern and northeastern parts of the country reaches within 4 to 7 degrees of freezing point. 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Over Dhaka city … Heavy rainfall is characteristic of Bangladesh 's annual rainfall of have!