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GOVERNMENT OF PONDICHERRY |
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METEOROLOGICAL
AND RELATED DATA
(A)
Meteorological Data a)
Climate The recorded maximum and minimum
temperatures at Pondicherry is 35.7ºC in the month of June and 20.9ºC in
the month of January respectively. The average maximum temperature is 31.5ºC
and the average minimum temperature is 23.9ºC b)
Rainfall Wet season persists mainly during the
north east monsoon period between October and December. The average annual
rainfall is about 1300 mm. c)
Wind During south west monsoon between March
and September, the wind blows predominantly from the south. During June,
July and August, strong wind is experienced from south west direction in
mornings from south during afternoons and from south east during nights.
The north east monsoon starts in October. Wind first blows from the coast
then changes to northernly direction in December and gradually decreases
in force during January and February. The direction also changes from
northeast to east. Northeast monsoon winds are usually stronger than the
southeast monsoon winds. All through the year, wind speed is between 1 and
19 Km/hour.
d)
Cyclones The coast is affected by the storms
occurring during the north east monsoon (October to December). The
occurrence of storms in this region is about once in three years.
Pondicherry is mainly affected by cyclone generated waves during this
period. (B)
Oceanographic Data a)
Tides Recorded tide levels at Pondicherry with
respect to chart datum are: MHWS +
1.30 m MHWN +
1.00 m MLWN +
0.70 m MLWS +
0.49 m b)
Currents The tidal currents observed in the
vicinity of Ariyankuppam river mouth indicates unidirectional current from
north to south during flooding as well as ebbing tides and the maximum
strength of the current as observed is 0.26 m/sec. c)
Waves The deepwater waves occur from the south
and south west during south west monsoon and from north east during the
north east monsoon. Wave heights rarely exceeds 0.9 m during these
periods. d)
Littoral Drifts The wave climate in this region induces
a predominant northerly drift from March to September. The return drift is
during November to February. The condition at Pondicherry are very similar
to those at Chennai. Therefore a gross northerly drift of about 0.9
million Cu m can be considered. (C) Geo-Technical Data Studies indicate that rock is not
expected upto – 20m below chart datum. Top layers of soil consist of
silty fine sand to medium sand followed by a layer of marine silty clay.
Below this is dense to very dense medium to coarse sand.
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