Sagar Biswas :
Winter days are losing charm and getting warmer nowadays in Bangladesh. Especially in Dhaka, it looks like a hot summer day when it is supposed to blow bone- chilling wind in this part of the season.
The scenario is all the same in neghbouring India, Myanmar and Pakistan too. This year’s winter is warmer in Delhi where usually a ‘chilly’ wind blows in mid-January. Naypyidaw is also experiencing extreme weather this winter while Islamabad is not an exception.
Experts say the present days are warmer because the Himalayan wind is getting warmer in this region because of El Nino’ impact, and some other factors have reduced the chance of extremely cold days in the near future.
The El Nino that has often been the nuisance of the monsoon in this part of the globe is also the reason for the ‘unusually warm winter season’ this year, they said.
When contacted, Nasreen Ahmad, Professor of Geography and Environment Department of Dhaka University, told The New Nation on Saturday, “Global temperature is rising and so, the winter is getting warmer as its reflection. The basic controlling factor of temperature is wind pressure, and the wind pressure is related to air movement. Wind usually moves high pressure to low pressure. In winter, the wind blows in the country from northeast to southeast direction.”
“In particular, the capital city Dhaka contains all factors to warming the winter. These are: Cutting trees, unplanned concrete structures, carbon emission from vehicles and factories, dust, using air conditioners and others. So, the winter is warming here each year,” she explained.
Usually, there are three different seasons in Bangladesh: a hot, humid summer from March to June; a cool, rainy monsoon season from June to October; and a cool, dry winter from October to March.
In general, maximum summer temperatures range between 30°C and 40°C while April is the warmest month in most parts of the country. On the other hand, January is the coldest month, when the average temperature for most of the country is about 10°C.
But now, the country is now experiencing comparatively warmer winter for the last five years. Normally, cold days tend to occur when the wind is blowing from the north, bringing Himalayan air south into the mid-latitudes. But the Himalayan air is now warming so rapidly, these cold days are now less cold than they were in the past.
Echoing the same, M Rasheduzzman, Senior Meteorologist of BMD said, “Winter is comparatively warmer this year. This winter is less cold than that of last five years. We also see that the temperature in average is 2-3°C higher than the previous years. Especially in Dhaka, the temperature is far higher than other parts of the country.”
“Its, however, nothing unusual in seaside localities, like Teknaf or Khepupara where temperatures remain between 20°C to 25°C in winter. But it may be highly unpredicted in Dhaka or other cities. Dhaka is experiencing an average temperature of 22 °C. The highest temperature in Dhaka was recorded 26.6 on Saturday,” the meteorologist said.
The Met officials observed that the country has been experiencing warmer winter due to less formation of cold waves this year. Besides, the fog is also not enough thick this winter for which adequate sunlight adding high temperature.
According to a recent study conducted by a US-based organization, the temperature over land areas has risen more than in the sea in the recent years.
‘Besides, the climate models which calculate the future trend in the climate showed that temperatures will continue to rise, and before the turn of the century, the increase will be about 3-5 °C over land and up to 7 °C over the oceans. The temperatures in winter are expected to rise even more,’ the study said.
The Met office in its forecast yesterday said mild cold wave is sweeping over Rangpur division and the regions of Srimangal and Noagaon and it may abate. Besides, moderate to thick fog may occur at places over the river basins and light to moderate fog may occur elsewhere over the country during mid night till morning.
However, the night temperature may rise slightly and day temperature may remain nearly unchanged over the country, the Met office said. Country witnessed lowest temperature yesterday in northern locality Badalgachhi 9.5°C and it was 28.4°C in southern district Patuakhali.
As per information provided by Met office, the lowest temperature in the country’s history was recorded at 2.8 degrees Celsius in Srimangal in 1968, in the then East Pakistan.
