Seasons in the Sea - A month-by-month guide to Central California sea life
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Windy ocean: Image credit-David Clague, MBARI

Winds, waves, and currents

in August

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Diver-at-work symbol (c) Kim Fulton-Bennett This page under construction.
Here are some of the topics that will be covered in this chapter. More text and images will eventually be added to this section. Thank you for your patience.

Physical processes in August:

  • The Pacific High moves north of the Central Coast so that Monterey Bay sits on the Southeast limb of the Pacific High. The strong Pacific High covers most of the Eastern Pacific, pushing Aleutian low-pressure systems far to the north. Because the high and low pressure areas are farther apart, atmospheric pressure gradients are lower, and thus winds are lighter.
  • Fog and overcast becomes less common (why less fog? - higher pressure leads to thinner marine layer? smaller differential between water temp and air temp? smaller differential between marine layer and upper air? less moisture in atmosphere? less advection of Pacific marine-layer fog toward coast). Less fog and lighter winds make life more pleasant for human beach goers. August is when the "real summer" typically begins on the Central Coast.
  • Lighter winds and mean less frequent upwelling events and more frequent "relaxation" events.
  • With less wind, less upwelling, and plenty of sunlight, surface waters becomes warmer and more stable within 10 miles of the coast, even in exposed areas. A shallow (10-20 meter) "surface mixed layer" often forms along the coast.
  • Upwelling currents and fronts become weaker, and seawater outside of protected "upwelling shadow" areas becomes more similar to that in these protected areas.
  • Upwelling due to internal waves and tidal currents along the edges of the Continental Shelf and Monterey Canyon may become more important at bringing nutrients toward the surface and triggering localized blooms of algae (some of which occur tens of meters below the sea surface.)
  • The California Current weakens at this time of year, and begins to meander more. The "Oceanic Season" begins as clear, blue, slightly warmer, but much saltier water from the California Current occasionally meanders in toward the coast.
  • When upwelling currents cease during calm periods and "relaxation"events, tongues of water from the California Current are more likely to be carried toward the coast. In some cases these "intrusions" of oceanic water can fill Monterey Bay with clear, blue, oceanic water (and animals) that might have originated a hundred miles offshore. In addition to being clear and very deep blue in color, this California Current water is slight warmer, much less salty, and much lower in sediment, nutrients, and chlorophyll (algae) than the water near shore. These tongues of oceanic water typically affect just the surface waters (down to 50 meters or so).
  • In deeper water, the California Undercurrent reaches maximum northward flow in SUMMER to early FALL, with maximum northward flow observed at 100-200 meters in July, and at 65 meters in August (at M1, just outside Monterey Bay).

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