The India Climate Observatory

Commentary, action and research on climate and development in India

A third dry week of monsoon 2014

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05 to 11 June is the first week. 12 to 18 June is the second week. 19 to 25 June is the third week. The bars represent the weeks and are divided by IMD's rainfall categories, with the length of each category in a bar showing the proportion of that category's number of districts. The colours used here match those used in IMD's weekly rainfall map (below) which displays the category-wise rainfall in the 36 meteorological sub-divisions (but not by district).

05 to 11 June is the first week. 12 to 18 June is the second week. 19 to 25 June is the third week. The bars represent the weeks and are divided by IMD’s rainfall categories, with the length of each category in a bar showing the proportion of that category’s number of districts. The colours used here match those used in IMD’s weekly rainfall map (below) which displays the category-wise rainfall in the 36 meteorological sub-divisions (but not by district).

The IMD weekly rainfall map for 19 to 25 June.

The IMD weekly rainfall map for 19 to 25 June.

We now have rain data for three complete weeks from the India Meteorological Department (IMD) and for all the districts that have reported the progress of the monsoon.

The overall picture remains grim. In the third week of the monsoon the number of districts that reported normal rains in that week (-19% to +19% of the average) is only 74. No rain (-100%) was reported by 71 districts Scanty rain (-99% to -60%) was reported by 221 districts, deficient rain (-59% to -20%) was reported by 125 districts, excess rain (+20% and more) was reported by 129 districts, and there was no data from 21 districts.

IMD_districts_table_3_weeksThe Department of Agriculture and Cooperation, of the Ministry of Agriculture, has already issued its guidance to states on the contingency plans to be followed for a delayed monsoon. That is why it is important to make available the district-level normals and rainfall departures – the meteorological sub-divisions are too broad for such analysis and are irrelevant to any contingency plans and remedial work.

By end-June, when the IMD updates its outlook for the rest of monsoon 2014, we expect more detailed assessments of the districts to be publicly available – the agromet (agricultural meteorology section) already provides this to the states, with state agriculture departments given the responsibility of ensuring that the advice – which is especially important for farmers to plan the sowing of crop staples – reaches every panchayat.

The new measure of monsoon

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The changes that we find in the patterns, trends, intensity and quantity of India’s monsoon now require an overhaul in the way we assess what is satisfactory or not for environmental and human needs.

By Rahul Goswami

India’s summer monsoon is already late, and where it is late but active it is weak. The indications from the central earth science agencies (including the India Meteorological Department), from the Indian Institute of Tropical Meteorology, from the National Centre for Medium Range Weather Forecasting are that it will be the end of June before the summer monsoon system settles over central India and the western Gangetic plains. Even so, it will be a relief from the searing temperatures but will not assure sowing conditions for farmers and cultivators, nor will it add to the stores of water in major and minor reservoirs.

Districts reporting monsoon data, over two weeks, colour-coded under a revised categorisation (explained in the text) for weekly rainfall. The left bar in each pair is the second week, the right bar is the first. Most districts are coloured light red, signifying rainfall much below the weekly normal. Peach is for the lesser deficient category. Green is normal. The two blue hues - lighter and darker - are for the two excess categories. It is immediately apparent that 485 out of 618 reporting districts (78%) have experienced less rainfall than they should have at this stage of the monsoon.

Districts reporting monsoon data, over two weeks, colour-coded under a revised categorisation (explained in the text) for weekly rainfall. The left bar in each pair is the second week, the right bar is the first. Most districts are coloured light red, signifying rainfall much below the weekly normal. Peach is for the lesser deficient category. Green is normal. The two blue hues – lighter and darker – are for the two excess categories. It is immediately apparent that 485 out of 618 reporting districts (78%) have experienced less rainfall than they should have at this stage of the monsoon.

The situation is very much more worrying than it is presented as by the agencies and departments of the new NDA government, and by industry – which complains about duties and tariffs but pays no collective attention to the daily situation that attends the south-west monsoon. The Ministry of Agriculture has busied itself, since early 2014 May, with mentioning the new high of agricultural exports, with the apparent success of a new SMS service to farmers, with releasing the advance estimates for agricultural and horticultural production, with a review of the implementation of crop insurance schemes and there is one, only one, advisory issued for horticulture crop cultivators concerning what they must do “under the rain deficit conditions”.

Some of the problem – that is, an absence of urgency as the last week of June approaches with little evidence of the customary rains being deposited, and apparently little preparation for a deficit in rains – may be attributable to the manner in which basic rainfall data is assessed and distributed to the public. This is done by the IMD – and more recently by a new private sector that is exploiting the yawning gaps in data presentation and the delivery of timely forecasts.

It is however the IMD, the Ministry of Earth Sciences and the Department of Science and Technology that works with state government agencies and departments in the areas of water resources, agriculture and drinking water supply. With the enormous size of the constituencies that are affected by dwindling water supplies and late sowing, there is a very strong case for revising the terms with which rainfall is measured and the frequency with which forecasts are distributed to districts and settlements.

It is absurd that the primary indicator during the designated ‘monsoon months’, according to the IMD, which are June to September, is a weekly table and weekly map of sub-divisional rainfall. Such an approach is not only out of date in the very hour it is issued – and distributed via the media – it is also grossly negligent of the commendable and ubiquitous advances made by public sector science and private ingenuity alike concerning the handling and treatment of climatic and weather-related data for India.

The typical IMD weekly rain map showing the colour codes and data for India's 36 meteorological subdivisions. This presentation urgently needs to be retired in favour of a more granular (district) map that is updated as soon as new data is received.

The typical IMD weekly rain map showing the colour codes and data for India’s 36 meteorological subdivisions. This presentation urgently needs to be retired in favour of a more granular (district) map that is updated as soon as new data is received.

A dense network of weather stations complemented by dedicated satellites provides continuous coverage of the sub-continent, the northern Asian land mass, the surrounding oceans southwards until beyond the Tropic of Capricorn. Methods to simply and accurately funnel this stream of real-time data and imagery are available, mostly at no cost, in order to aid local administrations, farmers and cultivators, and all citizens. It is this availability and relative simplicity of use (block-level weather forecasts for 72 hours are now available as local language apps on smartphones) that needs to be encouraged by the official agencies. More so in a year like 2014 with a late and weak monsoon and an El Nino threatening.

That is why IMD’s hoary top level categorisation of rainfall weekly quantities in the subdivisions must be replaced, both for what they describe and for how frequently they are described. These currently are: ‘normal’ in a subdivision is rainfall that is up to +19% above a given period’s average and down to -19% from that same average; likewise excess is +20% and more, deficient is -20% to -59% and scanty is -60% to -99%. The ‘normals’ are calculated based on the mean weekly rainfall for the period 1951-2000 with monitoring done in 641 districts distributed amongst the 36 meteorological subdivisions.

However, as all those who are engaged in studying and planning for the effects and impacts of climate change recognise, the changes observed on the ground over the last 15 years (rainfall, temperature, intensity of rain, duration of dry and wet spells) have made the term ‘normal’ difficult to use so that it continues to have meaning. Worse, a ‘normal’ with a wide range – over 28 percentage points from a given centre for a location – can lull local administrations particularly to misread the signs and ignore, on the basis of administrative expediency, the need to prepare for contingency.

By categorising rainfall ‘normals’ and departures from  ‘normal’ to become more administratively impelling – these proposed corrections also simplify the interpretations possible for rainfall above and below ‘normals’ – greater awareness and preparedness of administrations, key agencies and citizens to the deficiencies of monsoon can be fostered. For the district tables below therefore, I have re-cast the categories as follows (all based on the long-term average provided by IMD): Normal in a district is +5% to -5%; Deficient 1 is -6% to -20%; Deficient 2 is -21% and more; Excess 1 is +6% to +20%; Excess 2 is +21% and more.

Using these revised categories we see that for the second week (2014 June 12 to 18) of rainfall recorded in the districts (618 out of 641 reported) in 20 districts only was the rainfall ‘normal’ for that week. Under the existing IMD category of normal, this number is 81 – thus 61 district collectors will have been informed that in their district there is nothing to worry about, whereas the difference between a below normal reading of -5% and one of -15% can have a lasting impact particularly in rainfed districts where the social and institutional capacities to manage water and to plan credit needs for late sowing may be weak. In the same way, under the existing IMD categories, the difference between the conditions of two adjacent communities, one living in a district with a ‘deficient’ reading of -50% and the other in the neighbouring district (and in the same subdivision) with a ‘scanty’ reading of -70% is no more than technical, for the same degree of contingency planning will be required.

Whereas, for the same second rainfall week the IMD categories were ‘No Rain’ in 80 districts, ‘Scanty’ in 241 districts and ‘Deficient’ in 130 districts, under the proposed revision they will simply be ‘Deficient 2’ with 449 districts – thereby showing dramatically how widespread the conditions of the late and weak monsoon 2014 are – and ‘Deficient 1’ with 36 districts. State departments of agriculture, which have long worked on the frontlines of monsoon emergencies, whether drought or flood, have several generations of institutional experience to call upon in such circumstances. In most states, by 12 June alerts began to be issued to farmers and cultivators on measures to take if the monsoon is 15 days late, 30 days late and if signs of ‘terminal drought’ appear. Such preparedness must quickly extend to other areas – water resources, drinking water, food and civil supplies – for which a new meteorological literacy is urgently needed.

ENSO, ISMR, EQUINOO and rain

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RG_ICP_20140605An editorial in the journal Current Science (25 May 2014) has helpfully linked three phenomena that will affect the monsoon of 2014. The first is the El Niño (and the El Niño Southern Oscillation or ENSO) over the Pacific Ocean, considered unfavourable for us and the monsoon. The editorial has pointed out that El Niño has featured in the news already, with likely impacts being considered such as “a decrease of about 1.75% of GDP”. The question the editorial asks is: how reliable is the forecast of an impending El Niño? When it does occur, will it bring a deficit monsoon or a drought inevitably?

The second phenomenon is the Indian summer monsoon rainfall (abbreviated to ISMR by those who study climate for the sub-continent). The Current Science editorial makes an important point which is, studying the relationship between the sufficiency of the monsoon, the GDP and food-grain production during 1950–2004 reveals that the magnitude of the adverse impact of deficit rainfall is much larger than the magnitude of the positive impact of above average rainfall. This means that India being able to predict the possibility of drought (and therefore factors that influence it such as the ENSO) is more important than being able to predict a good monsoon.

The editorial has said that the ISMR “is significantly correlated with this ENSO index, with the relationship explaining 29% of the variance of monsoon rainfall”. Thus the warm phase of ENSO, which is characterised by more rainfall over the equatorial central Pacific, is associated with a decrease in rainfall over India. Now that we know this, what are the implications for monsoon 2014? By April, the warm phase of ENSO has already commenced with enhanced convection/rainfall over the central Pacific and all the models predict that it will amplify and persist until the end of the summer monsoon (the models vary in how they look at linked phenomena and the specific conclusions but agree broadly that El Niño conditions are here.

While the editorial has said that by “mid-June we should get a better idea of whether an El Niño is imminent”, the already unfavourable ENSO conditions mean that the probability of drought has gone up to just over 30%. If an El Niño does fully develop by end-June, the chance of a drought increases to 70%.

The explanation becomes more complete with the assessment of the third phenomenon. This is the Equatorial Indian Ocean Oscillation (EQUINOO). In 2003, it was discovered that in addition to ENSO, EQUINOO plays an important role in the variations, from one year to the next, of the ISMR. There is what is called “a see-saw between a state with enhanced rainfall over western equatorial Indian Ocean and suppressed rainfall over eastern equatorial Indian Ocean” (and its opposite). How this becomes manifest from one year to the next is considered by climatologists to account for about 19% of the variance of the monsoon rainfall.

The equation that we will have to finish writing and balance in the next few weeks is this. During the Indian summer monsoon season, ENSO and EQUINOO are poorly correlated – an ENSO unfavourable to us can be counter-balanced to some degree by a favourable EQUINDO. When both are unfavourable to us, drought has occurred. But the records also show that twice recently, in 1963 and in 1997, a favourable EQUINDO has protected us from the harmful impact of an El Niño. We need, in short, to be watching closely multiple large climatic phenomena every day until at least end-June. Is the IMD up to the job?