B’lore weather back again

B’lore weather back again
Deccan Herald

Happy days are here again, and happier nights. Evenings are for hot pakodas and tea or coffee if you are a teetotaller. Or a noggin if you imbibe. Quite convivial to your friends and like-minded relatives. And, oh God, those misty mornings when you take your ‘constitutional’ in what is left of the greenery! Old-timers must be nodding their heads in silent approval; the City weather takes them back quite a way. So what if you have the sniffles or a hacking cough if you are slight asthmatic? Greedy builders and conniving politicians might have done their worst, chopping off much of the greenery and razing to the ground charming colonial bungalows in the manner of Mohammed Ghazni, but good old Bangalore has shown this winter that it is still alive and kicking.

Bangalore with a track record of maintaining steady weather and climate patterns was coldest in January 1884 when temperature dipped to 7.8 degrees celsius (that was just about a decade before Sir Winston Churchill arrived as a subaltern of Fourth Hussars cavalry regiment at the City, about whose climate he had high praise, to grow roses, collect butterflies and play polo for pastime), It came closest to that record in January 1992 when the mercury dropped to 10 degrees celsius. Otherwise, Bangalore has had steady temperatures in winter months. The present minimum temperature however has been between 14 and 15 degrees celsius, which is considered normal.

Brrr...it’s cold!!

According to Met Department Director A L Koppar, present chilly conditions are not something unusual. "There is an inter annual variation in weather patterns, and every season has its own typical weather pattern. However, there is a deviation in temperature levels, which is either more pronounced or diluted. When compared to this year, the minimum temperature last year was less pronounced (slightly warmer). Hence we feel that Bangalore has become abnormally cold this year," he said.

He said when the east-west moving easterly weather systems, which bring in moisture and chill, move away from a region, the temperature falls even further. And the affected regions usually are Tamil Nadu, Kerala, and the southern fringe of Karnataka, including Kolar, Bangalore, Mandya, Mysore, Chamarajnagar and Kodagu.

Mr Koppar says that the climate changes are documented once in every thirty years. "The City has not experienced any significant climate change over the past few decades, but it has developed a tendency to go higher. There has been a trend rise of 0.6 or 0.7 in the temperature levels, which is in tune with global warming," he said, adding that except for the summers and the rainy seasons, winter months have not witnessed any notable changes.

Summers to be hotter

"In a few years, the average summer temperature will rise to 37 degrees plus, and four out of ten summers will hit this mark. We might even have to change the average baseline for summer months, which is now 33 degrees and shift it to 37 degrees," he added.

Also, warmer temperatures produce more rains. The incidence of extreme events of rainfall and increasing drought patterns are all direct result of the raise in temperature levels.

Pollution a cause?

Greater the dust content, higher the temperature. The Suspended Particulate Matter (SPM) and the Respiratory Particulate Matter (RPM) helps warm the weather. "This is clearly visible when we compare the weather conditions in urban and rural regions. The rural areas will have normal temperature levels, while the urban areas experience higher temperature levels," he added.

What’s the weather like today?

Mr Koppar confides that predicting weather conditions is definitely difficult. “We would have forecast occurrence of fog in a specific time frame for the next morning.

Unfortunately, many times the predictions end up being the exact opposite, where Bangalore will have clear skies and no fog prevalence. We bear the constant brunt of having given wrong information,” he added.

Weather vs Climate; Clear the 'air' of confusion

Weather is a state of atmosphere at a given point of time at a given place. It changes rapidly over short time intervals.

Climate is the average weather of a place, and changes steadily and gradually, over hundreds of years in cycles.

- Both weather and climate change, in their own time frames.

Fog and Mist

These phenomena are due to interplay of low temperature and availability of quantum water vapour in the atmosphere. If either temperature or water vapour varies, fog or mist occurs.

Fog is a condition when there is little visibility of surroundings within a radius of 1,000 mts, and when the object is blurred.

Mist is a condition when objects can be ascertained within the radius of 1,000 mts, even if they are little hazy.

Alikallu phenomenon

Alikallu (hailstones) occur very rarely and only when there is sweltering heat, in summer months of March-April.

Here, the air mass rises 10 to 12 km high into the sky, even beyond the condensation level, and hits the 0 degree freezing line, to transform into ice particles.

Since Bangalore has rarely witnessed soaring temperature levels, hail stones are also a rarity.