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Why IMD’s rain math doesn’t add up

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Each blue bar represents the actual rainfall recorded by a district as a percentage of its normal. There are 614 district recordings in this chart.. The red dotted line is the 100% mark, and many of the bars end below, or way below, this mark. This is the district-level view of cumulative rainfall over eight rain weeks using the IMD's own data.

Each blue bar represents the actual rainfall recorded by a district as a percentage of its normal. There are 614 district recordings in this chart.. The red dotted line is the 100% mark, and many of the bars end below, or way below, this mark. This is the district-level view of cumulative rainfall over eight rain weeks using the IMD’s own data.

Over eight weeks of recorded monsoon rain, the district-level data available with the India Meteorological Department (IMD) portrays a picture that is very different from its ‘national’ and ‘regional’ advice about the strength and consistency of rainfall.

In its first weekly briefing on the monsoon of August 2014, IMD said: “For the country as a whole, cumulative rainfall during this year’s monsoon (01 June to 30 July 2014) has so far upto 30 July been 23% below the Long Period Average.” Out of 36 meteorological sub-divisions, said the IMD, the rainfall has been normal over 15 and deficient over 21 sub-divisions.

The four regional readings that make IMD's data look less worrisome than it actually is.

The four regional readings that make IMD’s data look less worrisome than it actually is.

However, here is a far more realistic reading of the monsoon season so far, from the IMD’s own data. For the 614 individual readings from districts that have regular rainfall readings, we have the following: 86 districts have registered scanty rainfall (-99% to -60%); 281 districts have registered deficient rainfall (-59% to -20%); 200 districts have registered normal rainfall (-19% to +19%); and 47 districts have registered excess rainfall (+20% and more).

What this means, and the chart I have provided to illustrate the 614 individual values leaves us in no doubt, is that 367 out of 614 districts have had meagre rain for eight weeks. This also means that over eight weeks where there should have been rainfall that – as the IMD predicted in early June – would be around 95% of the ‘long period average’, instead three out of five districts have had less than 80% of their usual quota.

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Monsoon mysteries, mundane mathematics

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Rainfall averages for the months of January to August 2013, nicely arranged in one handy panel.

Rainfall averages for the months of January to August 2013, nicely arranged in one handy panel.

June, July and August 2013 are behind us and India’s understanding of the south-west monsoon – and also of climate change during monsoon and outside the monsoon months – has scarcely improved.

Other than the announcements from the Indian Meteorological Department, which are unintelligible to anyone with even the smallest interest in monsoon and climate, there is little in India’s media or from official sources that helps turn an embarrassing scarcity of understanding into knowledge.

The IMD, I was told about two years ago by a senior crop scientist, is queried every day by officious underlings from New Delhi wanting to know weather conditions for wherever their bosses are to visit, and this means the ministers of the cabinet, sundry senior and junior ministers, all variety of politicians and all their scheming cronies and hangers-on. That is why the IMD has so many special forecasts for New Delhi on its website. For the Indian Meteorological Department, India outside Delhi seems to be an annoyance.

IMD-rainmap_imagedummyThere are science institutes, such as the Indian Institute of Tropical Meteorology, which is, as far as I can make out, the seat of the scientific inquiry into monsoon and climate. The communication about its work however is either dismal or absurdly comic. Scientists long ago realised that to be of use to society, they had to make their questions and answers understood by those whom they wish to serve.

In such a spirit, India’s monsoon and climate scientists and researchers ought to have begun their careers with a session before their grandmothers – could they explain their work to their grandmothers? If not, they ought not to have been accepted in their present jobs (and their grandmothers should be inducted instead, for the wealth of their traditional knowledge).

And this is why we have gobbledygook such as this – from the IMD, about the 2013 September forecast:

“The 5-parameter PCR model was also used to prepare probability forecasts for the pre-defined 3 (tercile) categories of rainfall during the second half of the monsoon season. These are below normal (<90% of LPA), near normal (90-110% of LPA), above normal (>110% of LPA). The tercile categories have equal climatological probabilities (33.33%  each).  The  forecasted  probabilities  for  the  September  2013  rainfall  over  the country as a whole in percentage for the above tercile categories are  31%,  53%, and 16% respectively.”

Can the Director General of Meteorology – who is the head of the IMD – explain this to his washerman, his gardener and the chap who sells him vegetables? If not, he ought to make way for someone who can, because India understands the DG of M not at all, and we’re not paying his salary and departmental budget from our taxes to be misspoken to about the rain.

Just so that you know, this verbally challenged gentleman is assisted in his duties by five Additional Directors General and by 20 Deputy Directors General. And when I examined where this chatty group is deployed, the Delhi obsession (or fear thereof) became immediately clear, for of the five Additionals, four are in Delhi (the fifth is in Pune), and of the 20 Deputies, ten are in Delhi (the others are over the capital’s horizon, toiling somewhere in the torpor of the sub-continent.

The IMD runs six regional meteorological centres – each ruled by a humourless Deputy Director General, all morbid conversationalists – and these are to be found at Mumbai, Chennai, New Delhi, Kolkata, Nagpur and Guwahati. Then the IMD has what it importantly calls ‘operational units’: meteorological centres at state capitals, forecasting offices, agro-meteorological advisory service centres, flood meteorological offices, area cyclone warning centres and cyclone warning centres. All important centres, all equally incoherent about their work, all equally clueless about how to speak simply with those who need the forecasts the most.

But the disease of obscurantist climatic communication is to be found also in the Indian Institute of Tropical Meteorology, to wit: “However, the extended range predictability arises from Monsoon Intraseasonal Oscillations (MISOs) which are the quasi-periodic northward propagating large-scale convective cloud bands that manifest as the active/break spells, as described earlier.”

What will it take to get these scientists and researchers to understand that monsoon, rain, weather and climate are of great interest to most adults amongst the country’s 1.25 billion-strong population, and that by mumbling only to each other in equations and formulae they continue to do us a mis-service, and in fact shirk their main duty?