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TANGENTS

Catching Up With Dipen

BY IHTISHAM KABIR
Dr. Dipen Bhattacharya is research physicist at the University of California Riverside, and professor at Riverside Community College, USA. Readers may remember him as co-founder of Anushandhitsu Chakra science club, subject of our column last year. Recendy he visited Dhaka and I learned about his current research.
Dipen is fascinated by the geological history of Bengal delta. He says that over the last 18,000 years, the sea level rose by 120m while the coastline receded by about 200 km. This rise was often accompanied by severe monsoons - perhaps over centuries - which caused great flooding followed by large deposits of sedimentation.
During the worst period, the sea may have reached south of Dhaka, but no signs of sea intrusion have been found north, for example, in Sylhet.
Bengal delta renews itself every 100,000 to 200,000 years, the cycle of the ice age. At the height of the ice age, oceans retreat and the weather becomes dry. At its end, oceans return, possibly invading dry land. The weather becomes wetter. Flooding brings fresh sediment deposits and the new delta starts forming. The last time the delta building process started was perhaps 8,000 to 9,000 years ago.
Why is Dipen's research relevant? A natural outcome is an estimation of the inundation that Bangladesh would face with the sea level rise that many expect in coming decades.
For this estimation, Dipen needed elevation data for entire Bangladesh. Currently available data, based on satellite images, does not show the true elevation of the Sundarbans due to its tree canopy. So the height of trees was also needed.
Dipen, working with colleague Witold Fraczek, took historical sedimentation into account since that reduces inundation. They also guessed the rate at which the delta sinks due to sedimentation.
The upshot? A one meter rise in sea level would inundate 6-7% of Bangladesh, while two meters would inundate 11%, Dipen estimates. However, he warns that his estimates carry inherent errors of a few percent due to errors embedded in the satellite data.
Even in submerged areas, patches of land will remain dry. “It is imperative to identify these future potential dry areas and incorporate them into adaptation schemes," he says, “for example, by concentrating infrastructure there.”
Shifting gears, we discussed Dipen's second Bangla novel, Ditar Ghori (Dita's Watch.) A complex allegorical tale with loose parallels to our Liberation War, it chronicles the struggle between a country with a culture of watch-making and a foreign force which hates measuring time.
The foreign force occupies the country. It proceeds to eliminate the measurement of time by first banning the second hand, then the minute hand, and finally the hour hand.
Along with historical and moral metaphors, Dipen also introduces quantum mechanics into the story. There are parallel universes and philosophical discussions. There are heroes, villains and collaborators, including a watchmaker who is captured by the occupying force which then threatens his young daughter to make him collaborate.
Ditar Ghori, soon to be published by Prothoma, promises to be thought-provoking and enjoyable reading.
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