3) Ocean Basics

Coriolis Deflection: In the Southern Hemisphere, Coriolis deflection occurs to the left (west), while in the Northern Hemisphere it occurs to the right (east).
Southeast Trade Winds: These winds sink and then flow back to the Intertropical Convergence Zone (ITCZ), moving out of the Southeast.
Northeast Trade Winds: Similar dynamics observed over the Northern Hemisphere.
Equatorial Wind Behavior: As the southeast trade winds cross the Equator, the orientation of the Coriolis effect flips, causing winds to shift direction.
- At this juncture, the Southeast Trade Winds can extend up to about ten degrees north into the Northern Hemisphere, especially during winter as the ITCZ moves southward.
Thunderstorms: Embedded in the ITCZ, frequent thunderstorms can be observed.
Midlatitude Storm Development: Notable storm systems can be found around the Deep Southern Pacific Ocean, characterized by a few midlatitude storm systems.

A video clip is presented showcasing a lone sailor’s experience in the doldrums, highlighting:
- Large clouds and thunderstorms all around.
- Challenges of sailing through these regions with minimal wind.
- Observations of rain and lightning during his passage.

Lectures Agenda: Planned content over the next four lectures centers on oceanic features:
- Today: Basics about oceans (distribution, depth, temperature, salinity).
- Tuesday: General patterns of ocean circulation (surface and deep currents).
- Thursday: Atmospheric circulation including discussion on ENSO (El Niño-Southern Oscillation).
- Following Tuesday: Exploration of Polar Oceans.

Engaged students in a discussion about why oceans matter. Notable answers included:
- Carbon Sink: Oceans absorb a significant portion of carbon emissions, approximately 50% stays in the atmosphere, the other half is taken up by oceanic plants.
- Energy Redistribution: Oceans circulate warm air from the equator to the poles, influencing climate and livability.
- Biodiversity Source: Oceans support a variety of marine life, contributing significantly to diets worldwide (20% of animal-sourced protein).
Basic Ocean Statistics:
- Cover approximately 70% of the Earth’s surface.
- Five major oceans: Pacific, Atlantic, Indian, Arctic, Southern.
- Southern Ocean is uniquely significant as it connects other oceans and plays a critical role in climate stability.

Average Ocean Depth: Approximately 4 kilometers deep; notably deeper than average land elevations (1 kilometer).
Age of Oceans: Established to be about 4.4 billion years old, with the oldest known solid pieces of Earth dating back to this period.
Liquid Water Presence: Indicated prior to solid rock formations, major findings overturned previous ideas about early Earth conditions.

Salinity:
- Oceans average 35 parts per thousand salinity; ranges between 33-37 ppt.
- Major salts are sodium and chloride, making up table salt (NaCl).
Temperature Distribution:
- Sea Surface Temperature (SST) generally decreases moving away from the equator.
- Western sides of ocean basins are typically warmer than eastern sides due to current circulation patterns.

Salinity Influences: Major factors affecting salinity include:
- Evaporation rates vs. initial precipitation levels. Areas of high evaporation (> precipitation) are saltier.
- Freshwater input from rivers and melting ice sheets.
Density and Circulation: Denser, saltier waters can sink, influencing deep ocean circulation dynamics.

Ocean surface temperatures reflect regional climatology and help define weather patterns.
Evaporation and Precipitation Cycles:
- Regions of high evaporation correlate with lower precipitation, creating arid zones.
The Mediterranean Sea's salinity is explained by its isolation, leading to remarkable evaporation without notable precipitation.

Future Lectures: Students to explore sea currents, atmospheric systems, and how they are integrally related.