Cyclone Biparjoy is now completely detached from the monsoonal flow and will not adversely impact the advance of the rain-bearing system or its performance, the India Meteorological Department said on Tuesday. Addressing a press conference here, IMD chief Mrutyunjay Mohapatra said the cyclone, however, helped the monsoon advance over southern parts of the peninsula by increasing the cross-equatorial flow over the Arabian Sea.
“Now, it is completely detached from the monsoonal flow. We do not expect any largescale impact either on the monsoon advance or its performance,” he said. Scientists had earlier said the cyclone pulled the moisture and convection, impacting the intensity of the monsoon and delaying its onset over Kerala.
Meteorologists had said further progress of the monsoon beyond southern parts of the peninsula will happen after the cyclone degenerates. The monsoon hit India on June 8 with its onset over Kerala, a week later than normal.
Research shows a delay in the monsoon onset over Kerala (MOK) does not necessarily mean a delay in the monsoon onset over northwest India.
However, a delay in the monsoon onset over Kerala is generally associated with a delay in onset at least over the southern states and Mumbai. Scientists say a delayed MOK also does not impact the total rainfall over the country during the season. India is expected to get normal rainfall during the southwest monsoon season despite the evolving El Nino conditions, the IMD had earlier said.
Amid the developments, let’s take a look at what El Nino is and how it affects monsoons:
What is El Nino?
El Nino is a climate pattern characterized by the abnormal warming of surface waters in the eastern tropical Pacific Ocean. It is part of a larger phenomenon known as the El Niño-Southern Oscillation (ENSO), with La Niña being its “cool phase.”
El Niño affects ocean temperatures, currents, coastal fisheries, and local weather patterns across regions from Australia to South America. El Nino events occur irregularly, typically every two to seven years, but they are not predictable like regular cycles. The term “El Nino” originated from Spanish immigrants who noticed the appearance of unusually warm water off the coast of Peru. It was named after the Christ Child, as the phenomenon often occurred around Christmas, according to a report by National Geographic.
In the 1930s, climatologists, led by Sir Gilbert Walker, discovered the simultaneous occurrence of El Nino and the Southern Oscillation, which refers to changes in air pressure over the tropical Pacific Ocean. These two phenomena are now referred to as El Nino-Southern Oscillation (ENSO), and the terms “El Niño” and “ENSO” are often used interchangeably by scientists.
How Does El Nino Affect Monsoons?
El Niño refers to the warming of the ocean surface, specifically the central and eastern tropical Pacific Ocean, which leads to above-average sea surface temperatures. This warming effect influences atmospheric patterns, causing changes in weather systems and circulation. In the case of India, El Niño has been associated with a weakening of the monsoon circulation, resulting in a reduction in rainfall during the monsoon season, according to a report by CNBC-TV18.
Historically, India has experienced below-average rainfall during most El Niño years. This can have significant consequences for the country’s agricultural sector and water resources. Insufficient rainfall can lead to drought conditions, impacting crop production and necessitating restrictions on food grain exports, the report explains.
The El Nino conditions this year follow three consecutive La Nina years. La Nina, which is the opposite of El Nino, typically brings good rainfall during the monsoon season. Northwest India is expected to see normal to below-normal rainfall. East and northeast, central, and south peninsula are expected to receive normal rainfall at 94-106 per cent of the long-period average.
Rainfall less than 90 per cent of the long-period average is considered ‘deficient’, between 90 per cent and 95 per cent is ‘below normal’, between 105 per cent and 110 per cent is ‘above normal’ and more than 100 per cent is ‘excess’ precipitation. Normal rainfall is critical for India’s agricultural landscape, with 52 per cent of the net cultivated area relying on it. It is also crucial for replenishing reservoirs critical for drinking water, apart from power generation across the country.
Rainfed agriculture accounts for about 40 per cent of the country’s total food production, making it a crucial contributor to India’s food security and economic stability.
PTI contributed to this report
Comments
0 comment