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LatestPhoto
Captain Bob Wallace raises the main sail in order to take advantage of the northeast monsoon winds.
Photo: Chris Johnson

January 24, 2003
Northeast Monsoon Season
  Real Audio Report
  28k


Log Transcript

This is Genevieve Johnson speaking to you from the Indian Ocean, as we sail along the western shelf of the Maldive Islands.

Life on the open sea is dictated by the winds for they affect every part of our existence. Sometimes a strong blow can be a blessing, assisting us in travelling in a desired direction under the power of nature. At other times, we must face strong winds head on in order to reach our destination, or as is often the case, to keep up with sperm whales.

We have recently started searching for sperm whales in the waters of a new country-the Maldives. As well as having to acquaint ourselves with the shoals, harbor approaches and reefs of a new region, we must also face the challenges of a new monsoonal season.

The Maldives is a small nation consisting of hundreds of atolls that are spread along a narrow, vertical chain between the northern and southern hemispheres (although the majority of the islands are in the north). Since leaving the Seychelles just over a month ago, where the prevailing winds came from the southwest, we are now experiencing the effects of the Northeast monsoon in which the winds prevail from the northeast.

LatestPhoto
The wind direction during the Northeast monsoon season in the Northern Hemisphere of the Indian Ocean during the months of December to March.
Map: Chris Johnson

The northern Indian Ocean is dominated by the Northeast (NE) and Southwest (SW) monsoon seasons. Although other areas experience monsoon seasons, the northern Indian Ocean is unusual, being the only ocean that is landlocked to the north. The word "monsoon" is derived from the Arabic word 'mawsim' meaning a fixed season, and it applies equally to the prevailing winds and to the characteristics of the season, including rainfall, temperature and cloud cover.

We are currently in the midst of the NE monsoon - the cooler, calmer season and the best time to be searching for whales. At this time of year, the climate is generally dry, the skies clear and the temperature relatively comfortable-in the vicinity of 30 degrees Celsius. April to May is usually hot and is the transitional period between the two monsoon seasons. Around this time, the SW monsoon, also called "the rainy season", finally arrives to bring relief from the intense heat of the previous month. The months from May through October are characterized by torrential rainstorms each day (though most days also have long periods of sunshine) spectacular thunderstorms, lightening shows and moist, humid conditions that can be oppressive.

Whereas the ocean that washes the northern shores of the Indian Ocean remains at a fairly constant temperature throughout the year, the Asian landmass warms and cools through a wider temperature range, and the difference between land and sea temperatures is what drives the monsoon winds. The way this works is that during the northern summer, the landmass gets much hotter than the adjacent ocean waters. The warm ground heats the air above it and as it expands, it becomes less dense, thereby creating space into which the denser air over the ocean can expand. This draws air toward Asia and the Indian subcontinent from the sea, creating the SW monsoon. In the winter, the land mass cools and the less dense air above the warmer sea draws air off the land, which sets up the NE monsoon.

During the NE Monsoon, the wind blows throughout the entire Indian Ocean at Force 4 or 5 (17 to 21 Knots) about 75% of the time and its influence stretches right across the entire, northern Indian Ocean. This is the kind of weather that sailing boats take advantage of and is why at particular times of year, you find the majority of boats sailing in the same direction with the wind behind them.

LatestPhoto
The wind direction during the Southwest monsoon season in the Northern Hemisphere of the Indian Ocean during the months of May to October.
Map: Chris Johnson

Because most islands of the Maldives' lie just above the equator the winds in the more southerly islands are often weaker, and there are whole days of calm or light winds. So far we have been experiencing an even mixture of strong winds and calms. On less windy or windless days, we have had great success in collecting data. However, when the monsoon winds begin to stir, our lives are transformed and tasks such as cooking dinner, that were accomplished quickly and easily yesterday, become, when the boat is thrashing about in every direction, very difficult and very slow.

We have continually found that sperm whales often travel upwind when we are around. Back in the days of sailing ships, this may have caused a natural selection of whales that escaped their pursuers in this manner. However, that is only a guess. What we can say for sure is that the winds of the monsoon seasons make tracking sperm whales much more challenging.

Links:

  • Learn more about the Indian Ocean and how wind affects the lives of the crew.
  • Did you know that whale are protected in the Indian Ocean? - Click here to find out more.
  • What did the crew of the Odyssey report on one year ago in Australia? Two years ago in Kiribati?

    Written by Genevieve Johnson

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