Three weeks of rainfall during the ‘official’ monsoon (which both within meteorological circles and outside is still said to begin on 1 June) season, we are now able to present the week by week trend.
The graphic (click for full size image) shows the distribution of districts according to our expanded measure for rainfall adequacy. We call this expanded as it has 12 categories (11 plus ‘no data’) which we debuted in 2015.
To be used mainly as a planning and response indicator – such as preparing for the consequences of a dry spell or readying contingency plans if continued heavy rainfall make flooding a likelihood – our expanded measure also provides a weekly snapshot of rainfall at the district level. These snapshots, which in the graphic take the form of coloured horizontal bars, when stacked together give us a trend.
The indiaclimate visualisation of rainfall distribution by districts using our 12-grade category scale.
What we see from the bars that represent district rainfall distribution for three weeks is that the 2017 monsoon has for this period been what the India Meteorological Department first forecast in April, and then confirmed in May: that this year’s monsoon will be normal.
In each horizontal bar the most important category is the one marked “+10% to -10%” as this is the ‘core’ normal range of 10% above and below the long-term average. Since our time-frame for each snapshot is one week, this means the long-term average rainfall for a district for that week. Next in importance are the two categories that follow, above and below. These are the “-11% to -20%” and “+11% to +20%” and may be interpreted as satisfactory.
Thus we see that for the week ending 07 June (the lowest bar) 41 districts recorded normal rainfall for that week, 22 recorded satisfactory (but below normal) and 15 recorded satisfactory (but above normal). The similar distribution the following week, that is ending 14 June and the middle bar, was 39, 26 and 11. And the distribution for the latest week, that is ending 21 June and the top bar, is 61, 35 and 21.
However as the monsoon has weakened over the last few days and may not regain its customary vigour for this time of the year until 27 or 28 June, we expect our next instalment to show more districts in the browner shades towards the left of the categories bar.
You can follow our monsoon data, graphics and commentary on both our website and twitter channel.
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