Against the backdrop of the deadliest deluge in Kerala, the IMD on Friday said a new technology has been developed to assess the rise of water level in rivers and reservoirs by rain and which can help State Governments to minutely monitor the impact of rainfall. The technology called the 'Impact Based Forecasting Approach' shows "pre-event scenario" that can help authorities in taking real-time decisions.
At an event organised by the Centre for Science and Environment, IMD Director General KJ Ramesh said the new technology will be helpful for every state authority to take decision. "We can run this system in pre-event scenario. We are now in a position to use to this technology into service. We should be able to generate a scenario where we can take decisions to release water or not release it," he said. The IMD DG admitted that excessive rainfall that led to floods in Kerala were a result of climate change and in terms of rainfall it was very heavy.
The heavy downpour that ravaged Kerala for a fortnight ending August 21 caused death of around 500 people and economic damages worth over Rs 40,000 crore. Kerala Chief Minister Pinarayi Vijayan had said in the State Assembly that there were "lapses" on the part of the IMD's rain forecast.
The IMD had forecast an estimated 98.5 mm rain in the state between 9 and 15 August, but Kerala received was 352.2 mm of rainfall, Vijayan said.
"The number of cyclones have increased from 10 to 18 every year as reported in Nature magazine and secondly quantum of precipitation which was 13 days has come down to 10 days," he said.
IMD issues its forecast for the June-September monsoon season in April, which is based on the Ensemble Statistical Forecasting System that uses five predictors. These predictors along with some equations are used by scientists to carry out a statistical analysis to finally come out with a forecast.
The problem is that this method uses data from the past 100 years to come up with a forecast when many of the relationships between global climate factors have changed.
The dynamical forecast system, on the other hand, is based on current physical observations of the atmosphere, cloud properties and oceans, which can then be used to get a forecast. The observations are used to run the model on a supercomputer at IITM Pune to arrive at a rainfall forecast
There is another technology which would help in identifying warm ocean segments that are contributing to the rapid intensification of the systems.
Cyclone Ockhi's unpredictability was due to such warm ocean segments, following which the technology was developed in October, Ramesh said.
Ockhi is the first severe cyclonic storm in almost 40 years to have travelled about 2,400 kilometres from the Bay of Bengal to as far as the Gujarat coast, a senior Met Department official said.
CSE Director General Sunita Narain stressed on the need to plan "deliberately for drainage" to prevent disasters like Kerala floods.
"Every river, pond, paddy field and city should be mapped and protected at all costs," Narain said.
"Every home, institution, village and city must be required to do rainwater harvesting so that rain can be channelised and recharged," she said.