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Monsoon Meter: How much rain did India get

July 18, 2007 15:15 IST
Southwest Monsoon was vigorous/active over East Rajasthan and the Gujarat region during many days and over West Rajasthan, Konkan and Goa and Madhya Maharashtra on a few days of the week ending July 11.

Widespread to fairly widespread rainfall occurred over these regions during the remaining days of the week. Scattered heavy to very heavy falls with isolated extremely heavy falls also occurred over Gujarat and Rajasthan on a few days.

Southwest monsoon was vigorous/active over Gangetic West Bengal, Jharkhand and Orissa during 5th to 7th, Chhattisgarh on 7th, East Madhya Pradesh on 7th and 8th and West Madhya Pradesh on 9th.

Fairly widespread / widespread rainfall also occurred over West Madhya Pradesh during many days and East Madhya Pradesh & Chhattisgarh on a few days of the remaining period of the week.

Scattered heavy to very heavy rainfall with isolated extremely heavy falls occurred over Gangetic West Bengal & Orissa during 5th-7th and over West Madhya Pradesh during 8th & 9th. Monsoons were active/vigorous over Kerala, Karnataka and Vidarbha during a few days of the week.

Rain/thundershowers occurred at many places over these sub-divisions during remaining days of the week. Southwest monsoon was active over Western Himalayan region on 6th, 8th and 9th when fairly widespread rain/thundershower with isolated heavy falls occurred over this region.

Fairly widespread /widespread rainfall occurred over Andaman & Nicobar Islands and Nagaland, Manipur, Mizoram & Tripura during many days and Assam & Meghalaya, Arunachal Pradesh, Sub-Himalayan West Bengal & Sikkim and Bihar on a few days of the week.

Isolated to scattered rainfall occurred over remaining parts of the country during many days of the week. Rainfall during the week was 70.5 mm as against a normal of 65.1 mm, a deviation of +8 %.

Distribution of rainfall

In terms of distribution of rainfall across the 36 meteorological zones, in the week under review 18 divisions received excess to normal rainfall and the rest 18 divisions received deficient to scanty rainfall. However, cumulative rainfall for the first 5 weeks of this monsoon season was normal in 29 met divisions and deficient in 7 out of 36 meteorological sub- divisions.

Cumulative Rainfall till July 04, 2007

The actual cumulative rainfall was 310.8 mm against the normal of 262.6 mm, a deviation of +18%.


Outlook for the week ending July 11, 2007 from IMD

According to the IMD, a low-pressure area is likely to form over North Bay of Bengal around 13th. Under its influence, increase in rainfall activity is likely over east & adjoining central India during 13th-15th. Increase in rainfall activity over plains of northwest India is also likely.

Vulnerability of Kharif crops to rainfall deficiency

The table below gives the approximate proportion of production of certain kharif crops that are being grown in the met divisions that are presently in the deficient/scanty category. The idea here is to track how this proportion moves as the monsoon progresses on a weekly basis. Care must be taken while interpreting these figures as this relation is not indicative of actual production, but only reflects which crops could be affected by deficiency in monsoon under ceteris paribus conditions. Two basic assumptions have been made here:

Around 22% of our land area is well irrigated which really means that the crops grown here are immune to monsoons. The proportion of crops grown in these areas is excluded here since their production is not really dependent on the monsoons.

There may be some crops which may not require very high rainfall and could see higher production despite lower quantity of rainfall received, but are still included in this vulnerability matrix. Again, excess rainfall can also have a negative impact on growth at times as in states like Gujarat, which have received excess rainfall this season.

Monsoons have been fairly normal and consistent in most of the meteorological divisions till date. With Kharif sowing completed in almost all the regions, how the monsoons move forward at the development stage is more important.

However, deficit rainfalls in meteorological divisions of Jharkhand, Bihar & East Madhya Pradesh can be the cause of some vulnerability to crops like maize, rice, arhar and soybean.

Shilpa Jain is an economist with the National Commodity and Derivatives Exchange

Shilpa Jain, Commodity Online