Neither here, but not very much there either! India Meteorological Department (IMD) has sounded cautiously optimistic about a ‘likely to be normal monsoon' this year.
Importantly, it has said that there is a 24 per cent chance of it being not the case, wherein the annual rainy season could perform below normal.
The Met Department seemed to rule out any chances of the prevailing cooler-than-normal summer upending the monsoon. The cooling trend limits the extent to which land can heat up to the desired level to set up ideal conditions (as explained later) for the monsoon.
LARGER CONTEXT
This is the context obtaining closer home, against which the IMD has brought forth its first long-range forecast for this year's monsoon. One need not go back to beyond the previous season to see how prediction and performance could get unstuck if one does not get the basics right.
“Most of the operational long-range forecasts issued for the 2011 southwest monsoon rainfall were underestimating (sic) the actual rainfall and therefore were not very accurate.
“The main reason for the underestimation (sic)…. was due to the increased rainfall activity in the second half of the season in association with the sudden re-emergence of La Nina conditions over equatorial Pacific.”
This is how IMD's evidently laboured, but poorly drafted assessment of its performance in the end-of-the-season report for year 2011 read. Its long-range rain forecasts for the annual season had failed it for the nonce — but not only the once.
A year down the line, is the 2012 season shaping up to test its frayed nerves yet again?
DELAYED FORECAST
IMD is not telling, but it merely sought to delay its long-range forecasts for the crucial annual rainy season from the usual mid-April timeline.
The IMD alibi for delay in forecast: Let's hear out first what Big Brother Sacof (South Asian Climate Outlook Forum, which held its third annual session in Pune on April 19 and 20) has to say.
Talk first, Sacof-3 did, but not with any great conviction.
This is because Sacof, a World Meteorological Organisation-linked body representing a region with a common monsoon cause and shared worries, had, at the end of it all, come out with its non-committal best.
The consensus outlook at the end of the two-day brainstorming session said: “…there is uncertainty partly because of transition of La Nina conditions to neutral El Nino/Southern Oscillation (ENSO) conditions and some possibility for the emergence of El Nino during the later part of the monsoon season.
“….the large-scale summer monsoon rainfall for South Asia and the season (June to September) as a whole would most likely to be within the normal range. However, there is also a slight tendency for the South Asian summer monsoon rainfall to be below normal.”
PACIFIC LINK
The reference here were to key equatorial Pacific sea-surface conditions that seesaw from what are considered (though without cause-effect relationships) a monsoon-friendly La Nina (the type of which that fuelled successful monsoons in 2010 and 2011) and likely monsoon-killer El Nino (of year 2009 fame that set up the third worst drought year for India in the last 30 years).
It is another matter that India has had a successful monsoon even in the face of the dreaded El Nino in the past.
Sacof-3 only added to the uncertainty, after a few foreign weather models hinted about the possibilities of the monsoon failing, though for only the fourth time since 2000. The latest such came in as recently as in the last 48 hours of going to press with a leading US private forecaster pointing to the anomalous warming tendency in East Indian Ocean basin to set up what is called the negative phase of the Indian Ocean Dipole (IOD) – a bad enough recipe from the monsoon point of view.
The IOD replicates Pacific El Nino-La Nina in our own backyard, represented by warming of one flank of the Indian Ocean basin relative to the other.
When the west warms up, it aids the monsoon performance as it did on a trot for three years from 2006. The exact reverse happens during a negative IOD phase.
Now, a neutral Pacific with a bias towards El Nino combined with an evolving negative phase of the IOD is a deadly combination. The moot question is how the Indian monsoon would square up.
IOD THREAT
Sacof-3 outlook added for good measure: “Recent forecasts from a few coupled models suggest the possibility of development of a weak negative IOD event during the later part of 2012. In general, a negative IOD weakens the monsoon.
“But as the negative IOD is likely to evolve only in the last part or after the monsoon season, it may not have much impact on the monsoon circulation, at least in the early part of the monsoon season.
“There was consensus among the experts about the existence of large uncertainty in the forecast information this year, partly due to the weakening of La Nina and the expected ENSO-neutral state during the course of the summer monsoon season. As the possibility of emergence of El Nino cannot be ruled out, there is a need for continued monitoring of the regional and global climatic conditions…”
It is pertinent to point out here that a team of Japanese researchers led by Dr Toshio Yamagata had pointed to the tendency for subdued heating of the land surface over northwest India this summer and, indeed, for larger parts of the rest of the country.
Land must heat up, with strong to intense and sustained heat waves thrown in, to set up the required temperature/pressure gradient.
Intensity of the low pressure thus created over land during April-May (seasonal ‘low', with a core sitting over northwest India) decides the strength of the monsoon current.
HEATING ANOMALY
There are as yet no signs of this heating happening. No sustained heat waves have been reported either till date, with core heating confined to central and east-central India.
In the final analysis, it emerges that heating trends over land and sea in our own backyard – northwest India and east equatorial Indian Ocean – may have a big say on the fate of the 2012 monsoon.
The heating part aside, the Indian Ocean Dipole is said to have a more immediate and direct impact on the monsoon than the El Nino-La Nina phenomena. One is not too sure if the IMD has factored in this possibility fully in its 2012 monsoon forecasts.