Monsoon: Give the Met Dept a break. They are still on target and so are we!
Rajan Alexander 03 July 2012

While a 29% rainfall deficiency for June per se may look rather depressing, it is less than 5% of the average rainfall of 887mm in the monsoon and could be possibly made up for in the remaining season

The media has apparently gone totally berserk declaring the monsoon dead even as it has just arrived. Their headlines scream that June rainfall was deficient by a whopping 29% and that 83% of the country, including India's granary states of Punjab and Haryana, receiving deficient or scanty rainfall so far.

Self-titled "Food Security Analyst", Devinder Sharma of the NGO sector and founder member of Indian Against Corruption, also joined the scare mongering tamasha when he warned during an interview to a news channel, of the prospect of a negative agricultural growth rate due to a likely El Niño effect. This, Mr Sharma added, will further accentuate the downward pressure that the overall economy is currently experiencing that has seen our economic growth rate slip below the 7% levels-the first time over almost a decade!

It was left for deputy chairman of India's Planning Commission, Montek Singh Ahluwalia to strike a word caution to journalists:

"It's not the date of the onset of the monsoon; it's the overall level and distribution over the next four months. You can have a situation where the monsoon is absolutely on time and then it peters out. You can have a situation where the monsoon is one week late or even 10 days late, but then is healthy."

Though by academic training an economist, it is good to see Montek Singh Ahluwalia display commonsense understanding why the most frequently-used adjective used to describe the monsoon is vagaries.

As seen from the above table, June accounts on an average only 18% of the total rainfall during the south-west monsoon. The monsoon had been demonstrating a pattern change in recent times where the rainfall in June has been decreasing while that in July is increasing. Such a change in rainfall pattern is often used as 'evidence' by NGOs and environmental groups for the building their case of "catastrophic climate change".

In reality; such a change may even be beneficial for agriculture. Though such a trend may result in delayed sowing, the excess rains in July tends to leave sufficient soil moisture for standing crops to tide over even if August rainfall fails to live up to expectations. This makes the performance of July rains absolutely the key month to agriculture growth rate.  It is the failure of July rains that could prove 'catastrophic' for Indian agriculture.

Rains can accordingly fail in June but if July records near normal or even above average rainfall, we can be fairly optimistic that this year's agricultural growth will end up in the green. While a 29% rainfall deficiency for June (124 mm of rainfall as compared to 163.6 mm average) may per se look rather depressing, it has to be kept in mind this had been almost less than 40% of the deficiency that the country suffered for the same month during the 2009 monsoon season-also another El Niño year.

In 2009, the June rains were a whopping 47.2% below a 50-year average called as the long period average (LPA). The 2009 El Niño was one of the strongest in recorded history and despite this, the country managed +0.4% agriculture growth rate, suggesting that through irrigation expansion over the years, the vulnerability risk of our agriculture to poor monsoons have significantly reduced. There is no reason why this year should be any different. In fact, we are better placed this year than ever to register a new bumper food record. Whatever momentum in the growth rate in agriculture lost during the Kharif season could be offset in part or whole by the expected bumper Rabi crop this year. While El Niños negatively affect the south west monsoon, it has an extremely favourable influence on the north east monsoon.

On an average, the country receives around 887 mm of rainfall during the monsoon months-June-September. A 29% deficiency for June still adds to date, just a 4.93% deficiency from 887 mm total average SWM rainfall. Such a shortfall could be possibly made up either in part or whole during the next three months of the monsoon performance. This is really the crux Montek Singh Ahluwalia tried telling journalists.

As far as agriculture is concerned, it is not even necessary for the monsoon to perform 100% of its LPA. What matters is what its performance is during the months of July-August and its spatial distribution during these two key monsoon months. While a 10% deficiency of rainfall from its mean by itself should not pose a problem to agriculture, what is more critical is its spatial distribution.

This is particularly true this year as what concerned meteorologists more is not so much the mean rainfall for the country but the alignment of the monsoon troughs. It was the alignment of the north west monsoon trough that initially (in June) posed a problem while the north-eastern bay trough was found well developed. Such a formation however was not helpful for rest of India since entire moisture gets offloaded in the area of the trough here that explains the Assam floods. But the situation now has changed.

A study published in the International Journal of Climatology in 2009, carried out by Indian Institute of Tropical Meteorology (IITM) director BN Goswami et al showed that the monsoon is demonstrating a new pattern taking more time to reach the northern parts of the country. Instead of the normal onset date of 15th June, the onset at Nagpur is now taking place on 18th June with the Arabian Sea branch more active than the Bay of Bengal branch-the slowing of the monsoon being linked to the weakening of the wind shear. Wind shear is the difference in the wind speed at 1.5 km and at 12 km above the land surface.

While most global models have indicated a deficient monsoon (below 90% of LPA); the Indian Meteorological Department (IMD)'s forecast is 96% of LPA viz. a 'normal' monsoon. Since the model error of IMD is + 5%, their forecast in reality is between 91-101% of LPA, which means, despite the 29% deficiency in June rainfall, the IMD is still very much on target. So is this blog-our revised forecast last week was 94% of LPA or between 92%-98% of LPA at 95% confidence level! We see no reason to revise this forecast further downwards. So don't rule us or the IMD out just yet. If rains fail in July, then please by all means announce the demise of this season's monsoon.


Rajan Alexander
10 years ago
If all goes well and rains pickups by 5-6th (there are optimistic indications that this may well be the case), then as Amir Khan says, all is well.

If on the other hand there is further delay say till the 10th of this month, agriculture would be hit very badly and then probably all the observations of your comment may hold true.

So let us wait for a week and see how the rains pan out. Weather and climate being chaotic non-linear systems, no forecast can command absolute certainty. It is the huge uncertainties that make forecasting monsoon extremely hazardous.

About the El Niño, there are all kinds of suspicion whether it is an El Niño at all. It is usual for the Equatorial Pacific Sea Surface Temperatures (SSTs) to warm up during the boreal (northern Hemisphere)summer (till September) and then lose all its heat suddenly. The Regional Institute of Global Change (RIGC), Tokyo is of the opinion that this would be the case and as such factored this into their model projections.

There are besides two variations of an El Nino. The normal one goes eastward while the alternate or pseudo one called El Nino Modiki goes westward. There is strong suspicion that what we are experiencing is the Modiki version, but this needs to be confirmed. Their effects are different in general and India in particular. If the Modiki version, then 2003 monsoon would be a better comparison than 2010 to the present monsoon.

Regarding irrigation - what insulates us is that though our granary (SWM) Punjab and Haryana which is reeling under poor rainfall,they still have 93% of their arable land irrigated. During the rabi, our granary (NWM) are mainly Tamilnadu & Andhra, should see bumper crops because of the El Nino effect though winter wheat production in Punjab & Haryana may take a hit as the crop responds better to milder temperatures like cold waves.

About Rabi season likely to be a failure, yes and no. No because NE Monsoon rains respond favourably to El Nino and adversely to La Nina. The deficiency in one is offset by the other that more or less on an annual scale puts rainfall at or very near Long Period Average (LPA). Last year we had excess SWM rainfall but deficient NEM rainfall due to the La Nina effect that brought the annual rainfall within 101% of LPA. And because the NEM was deficient last year, there is low soil moisture that increases crop vulnerability to SWM delays. But since NEM rainfall is not evenly spread as the SWM, there are areas in the country that can be badly hit. But these would be crop specific variations; on the whole we should register another agriculture bumper, even if it is not statistically significant.

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10 years ago
A few points I want to make:

1. Irrigation in India is too less to make an impact on area under Pulses and Oilseeds - important drivers of inflation. Expect rates to spike if this continues. Reservoirs are hardly going to fill up with deficient rains.

2. If rains do poorly till mid July in the Central part of India, expect Kharif crops to be hit badly. Resowing, pest attacks and everything else will hit yields.

3. If Kharif does badly, Rabi will do worse, if one assumes normal rainfall pattern for the rest of the season and there are no additional showers around the Rabi season to provide additional moisture for the crop in a normally dry season.

Reservoirs will have barely usable supply for agriculture. District administrations will want to be extra cautious and conserve water for human uses through the summer rather than for agriculture. So little irrigation for Rabi. Farmers will stay away from crops like Wheat and prefer Gram which while more robust will still have lesser yields.

4. The situation seems to have parallels with the El Nin* affected monsoon in 2009. I really hope that does not hold true though. Or we are in for a bad time.

5. It is funny how the government prefers doles to farmers rather than investing in irrigation. There are projects that have actually been held up for 3 or 4 decades.

Oh, and by the way, this is Gunda!

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