Has Kerala's climate undergone a drastic change? The present deluge compared with the floods of last year, coupled with a drought-like situation in between, surely confirms it. Here's the scientific lowdown on climatic factors, far beyond our shores, that are causative!
Kerala's monsoon has completely lost its usual rain pattern. Changes in the South West monsoon dynamics are being reflected in the meteorological unpredictability that the state has been witnessing in recent years. The changes range from severe drought to cloudbursts and whose prime cause is global warming.
Topographical changes thanks to unscientific land use has also made Kerala a sitting duck for the water bombs coming from the 'monsoon gateway' in the north west equatorial Indian Ocean. In fact, the meteorologists have been predicting this process for a long time. There is a clear process - the Indian specialists, at the Centre for Earth Research and Environment Management, had started noticing the changes in the '60s and the international agencies acknowledged this in the '70s.
We, now, know it as the Indian Ocean dipole. The dipole is a seesaw effect in temperature between west and east Indian Ocean, causing a vertical separation of the 'monsoon jet'. While one stream crossed over to central India through the west of Kerala, the other section moved east along Sri Lanka coast denying Kerala its temporal spread of SW monsoon.
Till then, the monsoon gateway would receive Somali jets around mid-May and their eventual convergence would spark off the SW monsoon. Significant changes in Indian Ocean temperature changed the thermodynamics over this monsoon trough caused by a "very cunning" biological activity in the Pacific Ocean.
The surface temperature over the Pacific Ocean began dropping considerably with a proportionate increase in the Indian Ocean temperature. "It was detected that the Pacific was couriering its heat content into the Indian Ocean via the 'Indonesian through flow' (Ocean current along the Indonesian coast)" resulting in the stretching of a heat wall from the normal 200 mts to even two kms. With Indian Ocean becoming a dumping yard of Pacific heat, it results in a poorer spread of Nimbostratus clouds (Water vapour laden) in the peninsular region, especially, at the onset phase itself. Similarly, this weakening of the Findlater jet over the region allows convection to grow, resulting in unusual thundershowers during the monsoon regime. This sort of interaction and associated downpour makes the situation more complex.
Another phenomenon from the South China Sea had struck Kerala last week. Two monster cyclones (Separated only by 500 km) are approaching the South China Sea. This combo effect is sucking away all winds and water content from the Arabian Sea and the Indian Ocean and its impact is felt over Kerala and central India. Consequently, heavy rains are battering almost all states along the west coast and will subside only when those monster cyclones make landfall!
Note. Adapted from the ToI.
Tailpiece.
The rain was less compared to what it has been over the past week. It was a quiet Sunday! The day had started off with the bleak message that there would be no newspapers today because of breakdown in communication due to the deluge!
Monitored Mithun and Ammu who were travelling from Coimbatore to Bangalore on their scooty. They'd kicked off at 1000 hrs and reached their destination by 1900 hrs! Mini had left earlier by bus and reached around lunchtime; Sanil is already there. The four of them will be together, at Gottigere, for a while.
Kerala's monsoon has completely lost its usual rain pattern. Changes in the South West monsoon dynamics are being reflected in the meteorological unpredictability that the state has been witnessing in recent years. The changes range from severe drought to cloudbursts and whose prime cause is global warming.
Topographical changes thanks to unscientific land use has also made Kerala a sitting duck for the water bombs coming from the 'monsoon gateway' in the north west equatorial Indian Ocean. In fact, the meteorologists have been predicting this process for a long time. There is a clear process - the Indian specialists, at the Centre for Earth Research and Environment Management, had started noticing the changes in the '60s and the international agencies acknowledged this in the '70s.
We, now, know it as the Indian Ocean dipole. The dipole is a seesaw effect in temperature between west and east Indian Ocean, causing a vertical separation of the 'monsoon jet'. While one stream crossed over to central India through the west of Kerala, the other section moved east along Sri Lanka coast denying Kerala its temporal spread of SW monsoon.
Till then, the monsoon gateway would receive Somali jets around mid-May and their eventual convergence would spark off the SW monsoon. Significant changes in Indian Ocean temperature changed the thermodynamics over this monsoon trough caused by a "very cunning" biological activity in the Pacific Ocean.
The surface temperature over the Pacific Ocean began dropping considerably with a proportionate increase in the Indian Ocean temperature. "It was detected that the Pacific was couriering its heat content into the Indian Ocean via the 'Indonesian through flow' (Ocean current along the Indonesian coast)" resulting in the stretching of a heat wall from the normal 200 mts to even two kms. With Indian Ocean becoming a dumping yard of Pacific heat, it results in a poorer spread of Nimbostratus clouds (Water vapour laden) in the peninsular region, especially, at the onset phase itself. Similarly, this weakening of the Findlater jet over the region allows convection to grow, resulting in unusual thundershowers during the monsoon regime. This sort of interaction and associated downpour makes the situation more complex.
Another phenomenon from the South China Sea had struck Kerala last week. Two monster cyclones (Separated only by 500 km) are approaching the South China Sea. This combo effect is sucking away all winds and water content from the Arabian Sea and the Indian Ocean and its impact is felt over Kerala and central India. Consequently, heavy rains are battering almost all states along the west coast and will subside only when those monster cyclones make landfall!
Note. Adapted from the ToI.
Tailpiece.
The rain was less compared to what it has been over the past week. It was a quiet Sunday! The day had started off with the bleak message that there would be no newspapers today because of breakdown in communication due to the deluge!
Monitored Mithun and Ammu who were travelling from Coimbatore to Bangalore on their scooty. They'd kicked off at 1000 hrs and reached their destination by 1900 hrs! Mini had left earlier by bus and reached around lunchtime; Sanil is already there. The four of them will be together, at Gottigere, for a while.
No comments:
Post a Comment