24 March 2004

Wednesday, 24 March 2004

General Comment

The day dawned dark and gray, and while not particularly foreboding, it was not particularly promising either. The strong winds of yesterday had abated somewhat during the evening and night, but the swell had persisted, rendering attempts at sleep very difficult – more an exercise in trying to wedge yourself in the bunk between naps than getting a refreshing sleep. However, as the morning wore on conditions improved as the winds and swell subsided and eventually sunlight broke through. The weather has been very changeable all day – once going from sunshine to horizontal hail to rain to sunshine again all in the space of about 15 minutes. We have spent today doing a more detailed survey of the study area to identify the optimal site for the fertilizer injection. As well as underway measurements, CTD profiles have been taken through the day. We look forward to "pumping iron" tomorrow (and those of you who know me will recognize the irony in that statement).

The Physics Group.

The objective of the physics group on board is to improve our understanding of the physical factors that control the exchange of gases between the ocean and atmosphere and that influence the growth of the phytoplankton bloom. This involves making very accurate measurements of the temperature of the so-called skin-layer at the sea surface, as the solubility of gases in sea water depends on temperature. We also measure the structure of temperature, salinity, turbulence and light in the uppermost tens of metres of the ocean, and the winds, temperature, humidity and turbulence in the lowest layers of the atmosphere, as these control the exchange of gases between the ocean and atmosphere, and influence the plankton growth. Also, the behavior of the surface waves, especially as they break and inject bubbles into the ocean, is being measured. All of this involves using state-of-the art instruments in the very harsh marine environment, and thus far, all signs are good for a valuable and unique set of measurements being made in the next three weeks. These topics will be discussed in more detail in future bulletins.

The physics group includes:

  • Craig Stevens, NIWA
  • Murray Smith, NIWA
  • John McGregor, NIWA
  • Edward Abraham, NIWA
  • Brian Ward, Woods Hole Oceanographic Institution, USA
  • Peter Minnett, University of Miami, USA.

Peter J. Minnett, University of Miami.

The wind carrying spray from the crests of breaking waves.

Craig, Murray and John examine the display of the NIWA radar used to measure wave properties and breaking events upwind of the ship.

Even under harsh conditions, there are moments of majesty and beauty.

Peter Minnett.

Research subject: Oceans