3. Atmospheric Circulation

Case Study 1: 2023–2024 El Niño and Global Atmospheric Circulation

Geographical Thought & Perspectives:

• Walker’s Circulation Model (1924) – Large-scale atmospheric circulation in the tropics.
• Teleconnections in Climate Systems (Bjerknes, 1969) – Global climatic linkages.
• Anthropogenic Climate Change (IPCC, 1988–Present) – Human-induced disruptions in circulation patterns.

Models/Theories/Laws:

• Hadley Cell Expansion Theory – Shifting climate zones due to warming.
• El Niño-Southern Oscillation (ENSO) Model – Ocean-atmosphere interactions affecting global climate.
• Rossby Waves and Jet Stream Variability – Large-scale atmospheric wave patterns.

Recent Data:

• El Niño Event: Strong oceanic warming observed, but muted Southern Oscillation.
• Global Temperature Impact: 2023 recorded as the hottest year, with El Niño contributing to extreme weather.
• Walker Circulation Disruption: Atlantic and Indian Ocean warming reduced Pacific wind response.

Spatial Variation:

• Pacific Ocean: Strong warming in the eastern equatorial Pacific.
• Global Impact: Heatwaves, droughts, and extreme rainfall linked to circulation shifts.

Temporal Variation:

• Historical Trends: ENSO variability observed since 1982–83, 1997–98, 2015–16.
• Future Projections: Climate models suggest more frequent strong El Niño events.

Source:

• Nature Geoscience: “Strong 2023–2024 El Niño Generated by Ocean Dynamics”
• Copernicus Climate Change Service: “Global Climate Highlights 2024”

Insight:

The 2023–2024 El Niño validates ENSO models, demonstrating ocean-atmosphere interactions and their global climatic impacts.

Case Study 2: Kuroshio Extension and Atmospheric Circulation in Japan

Geographical Thought & Perspectives:

• Dynamic Climatology (Rossby, 1940s) – Planetary waves influence circulation.
• Ocean-Atmosphere Interactions (Charney, 1971) – Coupled climate systems.
• Regional Climate Variability (Lorenz, 1963) – Chaos theory in atmospheric circulation.

Models/Theories/Laws:

• Kuroshio Extension Dynamics – Warm ocean currents affecting atmospheric stability.
• Rossby Wave Propagation – Large-scale atmospheric wave patterns.
• Marine Heatwave Influence – Oceanic temperature anomalies affecting circulation.

Recent Data:

• Kuroshio Extension Shift: Extreme northward meander observed, reaching 40°N.
• Atmospheric Impact: Increased heat flux from ocean to atmosphere, altering regional climate.
• Marine Heatwave Conditions: Persistent high temperatures recorded off Japan’s coast.

Spatial Variation:

• Sanriku Coast: Warm subtropical waters replacing cold subarctic waters.
• Japan’s Climate: Increased air temperature and humidity due to oceanic heat release.

Temporal Variation:

• Historical Trends: Kuroshio Extension variability observed over decades.
• Future Projections: Continued ocean-atmosphere interactions expected to influence Japan’s climate.

Source:

• Journal of Oceanography: “Influence of Extreme Northward Meandered Kuroshio Extension on Ocean–Atmosphere Conditions”

Insight:

The Kuroshio Extension’s shift validates ocean-atmosphere interaction models, demonstrating regional climate variability.