The Hindu Business Line : Disquiet in South drains rain surplus to 10%

Thiruvananthapuram, July 11 All-India area weighed rainfall surplus for the country as a whole until Wednesday (July 9) has more than halved week-on-week to 10 per cent mainly on account of the prolonged scanty spell over the southern peninsula.

The surplus-to-normal precipitation for the country as a whole is now limited to 23 Met sub-divisions (28 till previous week), while the number of those recording deficient rain has risen to 12 (eight). Marathawada found its way back into the ‘scanty’ rainfall (-60 per cent to -99 per cent) list.

The ‘north-south divide’ could not have been more pronounced what with the surplus-to-normal rains in the North proving grossly insufficient to wash out the red smeared all over the southern half during the week. The skewed pattern was despite, and in some cases because of, the positive Indian Ocean Dipole (IOD) phase of seesawing sea surface temperatures.

NO EVEN SPREAD

This only serves to buttress the argument that, while being supportive to the monsoon cause overall, the IOD does not guarantee adequate coverage on either the spatial or temporal scale. If anything, it is known to rain down unexpected surpluses at the unlikeliest of places.

This was on view even last year, the second in a never-before series witnessing a positive IOD phase, when central India and the west coast were battered to near-deluge conditions. This year the scenario is playing out to the exact reverse, at least as of now.

The tell-tale result is there to see — the week ending July 9 has totted up a deficit of 20 per cent. When extrapolated to the season as a whole (June 1 to July 9), this has had the effect of depleting the rain surplus by just over a half to 10 per cent.

The break-up of Met subdivision-wise figures revealed the unprecedented levels to which recorded rainfall plumbed during the week – as in the case (in percentage figures) of Lakshadweep (97); Kerala (95); Marathawada (89); Rayalaseema (83); north interior Karnataka (82); south interior Karnataka (77); Konkan (72); Tamil Nadu and Puducherry (71).

These weekly deficits determined the extent to which these sub-divisions would get pushed further into the red till date - Marathawada topping the chart with 62 per cent, followed by Rayalaseema (47); north interior Karnataka (43); Kerala (39); Madhya Maharashtra and Gujarat (36 each); and coastal Andhra Pradesh (33).

ADDING TO SURPLUS

In contrast, north, northwest and east India have seen some record rainfall during the season. Punjab (+147 per cent) topped the chart of five sub-divisions with a surplus running into three figures. Eight others had two-digit surpluses counting upwards of 35 per cent (Jharkhand).

According to the India Meteorological Department (IMD) update, the prevailing ‘low’ stationed over northwest Madhya Pradesh on Friday was bracing for an interaction with an incoming western disturbance. Interactions between monsoon systems and westerly systems are known to generate copious rainfall over a large swathe in the neighbourhood.

IMD has forecast fairly widespread rainfall over northwest India during the next three days.

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