Gujarat cyclone foxes weather pundits

“The cyclone is rather rare or peculiar. First of all, conventionally the frequency of cyclones during this period of time is three times more in the Bay of Bengal than in Arabian sea. Occurrence of strong cyclones in Arabian Sea at this time, if not abnormal, is not common”, said Dr VV Thapliyal, deputy director general of meteorology (weather forecast) India Meteorological Department.

However, he said, the country experienced a similar situation in 1981 when two cyclones hit the Western coast by changing their course similarly.The whole phenomenon has a natural variability with tendency to changefrom one epoch to another, he explained.

About unseasonal rains in the nation akin to last year, Thapliyal said, “Some parts of the country are still experiencing withdrawal phase of monsoon and it would be too early to comment on occurrence of unseasonal rains.”

Meanwhile, the unusually prolonged monsoon, sporadic floods all over the country and the two devastating cyclones hitting Gujarat coast during this monsoon season have left the country’s meteorologists guessing about “all unusual things happening at one single time”.

The question gaining ground is that after El Nino, is it now the turn of its reverse phenomenon La Nina to cast its spell over the Indian monsoon?

An interesting theory propounded by the scientists at the Indian Institute of Tropical Meteorology in Pune speaks about the effect of La Nina phenomenon over the Indian monsoon and its impact especially in terms of heavy floods.

Speaking to The Indian Express, Dr RH Kripalani, senior scientific officer at IITM and one of the mainpersons behind the internationally acclaimed research work said, “The Indian monsoon rainfall has shown distinct epochs of above and below normal rainfall. The periods 1880-1895 and 1930-1963 are characterised by above normal rainfall, while the periods 1895-1930 and 1963-1990 are characterised by below normal rainfall.” The Indian monsoon rainfall may be entering into an above normal epoch with a turning point around 1990. This may be one of the reasons for India not experiencing a drought during the 1991-94 and the recent 1997 El Nino episodes. The study also suggests that the impact of La Nina is more severe during the above normal rainfall epochs.

than during the below normal rainfall epochs. “Since the Indian monsoon appears to have entered into an above normal rainfall, the impact of La Nina will be severe: that is more floods”, he said.

The La Nina phenomenon, believed to cause the opposite effect of El Nino, has been constantly strengthening ever since it started in July over the centralpacific.

“The Sea Surface Temperatures (SST) over this region is expected to be coolest during the months of February, March and April next year”, said Kripalani.

Thapliyal corroborated that the SSTs over the central pacific had started decreasing, however, he observed that the phenomenon would become significant only if temperatures fell by 3 to 4 degree Celsius.

“El Nino and La Nina are global phenomena and their impact cannot be seen on any particular State or region in India. It as to be assessed on a broad scale”, added Thapliyal.

The study has shown that the impact of El Nino is more severe during the below rainfall epochs than above normal rainfall epochs.