Monsoon 2016

Up ahead in the distance is a faint glimmer of hope – of bountiful rains, rivers running full, of dams overflowing with life-giving water and of farmers gazing at green fields with grain ready for harvesting. For the past two years, 2014 and 2015, the hopes of millions have been smashed to smithereens. Thousands have paid with their lives after facing two consecutive droughts due to the dreaded El Nino effect.

Will India be blessed with normal rainfall this year?  The question is difficult to answer with hard assurance for anyone, except of course the good Lord in Heaven, blessed be thy name.

El Nino, La Nina and Neutral Phase

El Nino and La Nina are the opposite phases of ENSO cycle (El Nino Southern Oscillation cycle).The warm phase is referred to as El Nino and the cooler phase is La Nina. Neutral phase is what occurs between the warm and cool phases.
ENSO cycle is the scientific term which refers to fluctuation in temperature between the ocean and atmosphere in East-Central Equatorial Pacific (source NOAA: National Oceanic and Atmospheric Administration, USA). This is the ocean that lies between Indonesia and South America.

During normal conditions, the easterly trade winds keep warm water near Indonesia and Philippines. In an El Nino year, the easterly winds weaken and warm water flows east towards South America. The increase in water temperature across Central & East Central Equatorial Pacific causes heavy rains in South America.

El Nino and Indian monsoon

The Indian Ocean Dipole (IOD), ie., difference in sea surface temperature between western pole in West Arabian Sea and eastern pole in Eastern Indian Ocean (south of Indonesia) is linked to ENSO cycle. Like the ENSO, IOD can be positive (warmer temperature in West Arabian Sea) or negative (cooler temperature).
Studies by the IITM (Indian Institute of Tropical Meteorology) have shown a link between a positive IOD or La Nina conditions in the Pacific with a delayed withdrawal of the Indian monsoon, and a shorter rainy season in case of a negative IOD or El Nino. La  Nina is strongly linked to good rains over Asia sub-continent, but this does not always hold true.
In the La Nina years 1974, 1999 and 2000, rains were below normal, whereas the El Nino year 1997 saw above average rainfall. Fact remains, no La Nina year has seen a drought (rains < 90%) nor has an El Nino event seen excess rainfall (> 110%).
It is this complex web of interactions between world weather conditions and oceanic currents which makes accurate predictions about the monsoons very difficult. The rise in green house gases (carbon dioxide and methane) further complicates the situation.
 

Hopes for India

Experts are of the opinion that the El Nino effect is weakening.
According to the Bureau of Meteorology, Government of Australia, (bulletin issued on 29 March 2016) most international climate models suggest a continuing weakening of El Nino. A repeat of El Nino is unlikely and return to neutral levels is possible by mid 2016. This is important for India as it marks the beginning of our monsoons.

Historical data available from the year 1900 onwards shows that of the 26 El Nino events recorded, 50% were followed by neutral years and 40% by the favored La Nina phenomenon.

Ocean temperature anomaly data

For meteorological purposes, equatorial pacific is divided into 4 parts, Nino 1 & 2, Nino 3.4 and Nino 4. Of relevance to the Indian monsoon is Nino 3.4. Data from  Bureau of Meteorology indicates gradual decline of Ocean surface temperature, an indication of waning El Nino effect.

Index	January	February	Temperature change
NINO3	+2.1	+1.6	0.5 °C cooler
NINO3.4	+2.2	+1.9	0.3 °C cooler
NINO4	+1.3	+1.3	0.0 °C No change

 

This data is not so reliable, due to “Spring Predictability Barrier”, which refers to a barrier in which predictability of climate models to make accurate forecasts is drastically reduced.

So, although the first forecasts indicate a favorable monsoon for India, more information will be available later in April. One can only hope that the rains are on time, normal and well distributed. 

Until then, we can only live in Hope of Deliverance.