CONTENT CURATION PRESENTATION for geography.pptx

This is Geography content, summarized to enhance better understanding of the content.

1. Atmosphere, weather and climate Presented by: Mpatho NKOSI

2. WHAT IS ATMOSPHERE? The atmosphere is defined as the mixture of gases surrounding the Earth, held in place by gravity .

3. Earth’s Atmospheric Layers

4. Temperature vs. Altitude on the layers of atmosphere Mesosphere; temperature decreases again with altitude Thermosphere: temperature increases sharply at higher altitudes.( Rohli & Li, 2021).

5. The Water Cycle Water transitions continuously among its solid (ice), liquid (water), gaseous (vapor) forms, cycling through the planet’s systems.

6. Humidity and Dew Point The dew point is the temperature at which air becomes saturated, and water vapor condenses into liquid. If relative humidity is at 100%, the dew point equals the actual air temperature(Sein et al., 2022)

7. Cloud types and weather

8. WEATHER Weather refers to atmospheric conditions (temperature, wind, precipitation) at a specific place and moment It fluctuates day-to-day. The study of weather is termed meteorology. A professional who examines and forecasts weather is known as a meteorologist. Weather is highly dynamic and changes frequently.

9. Understanding Climate Climate represents the usual weather patterns of a location over long periods of atleast 30 years Different global regions exhibit varied climates, such as hot and humid, arid, frigid, or temperate. Climate also includes those extreme conditions or deviations from the average condition- anomly . Climatic regions are areas with similar weather statistics, on land the location of climatic regions determines the location of the ecosystem, as it influences the ecosystem (Fasano et al., 2022).

10. Weather versus climate Weather Momentary, daily fluctuations. Frequent variations Meteorologist Climate Long-term average (30 years). Relatively consistent over decades Climatologist

11. Factors that influence the climate LATITUDE and ALTITUDE Regions near the equator receive more direct sunlight and thus are generally warmer. Polar areas get slanted rays that spread out more, making these regions colder. The poles also experience extreme seasonal variations in daylight—continuous daylight in summer and prolonged darkness in winter. Altitude (elevation above sea level) impacts temperature. As elevation increases, the air becomes thinner and cooler, typically dropping about 1 °C for every 165 m ascent (Louthan et al., 2021).

12. Latitude and Altitude

13. Proximity to Sea Coastal areas (near large water bodies) tend to have milder, more stable climates. Inland areas experience greater extremes in temperature. Example: Mumbai (coastal) enjoys moderate seasonal variation; Delhi (inland) swings between hot summers and cold winters.

14. Climate change in South Africa Temperatures rising 1.5× faster than global average. More frequent extreme rainfall events. Projected warming: 3–6°C by 2100 (inland). Impacts threaten water, food, health, biodiversity, and infrastructure (Ziervogel et al., 2014).

15. Biophysical Impacts- Biodiversity Grasslands at risk from woody encroachment and rising CO₂. Threats to Nama Karoo, Fynbos, Forests, Coastal Belt. Urgent need for integrated land-use and conservation planning

16. Biophysical impacts- Agriculture Staple crops (maize, wheat) projected to decline. Higher irrigation demand (↑ 4–6%). Sugarcane relatively stable; viticulture under pressure. Expansion of pests and diseases poses additional risks (Ziervogel et al., 2014,p.608).

17. Biophysical Impacts- Water Runoff projections: –20% to +60% by 2050 (high uncertainty). Increased risks of droughts and floods. Water quality concerns (temperature, nutrients). Land use will intensify water stress if climate dries (Ziervogel et al., 2014).

18. Global Air Circulation

19. The Tri-Cellular Circulation Earth’s atmosphere is structure into three circulation cells per hemisphere conveying heat away from the equator toward the poles. Hadley cells (0°–30° latitude) Ferrel Cell (30°–60° latitude) Polar Cell (60°–90° latitude)

20. Hadley Cells They begin with winds rising along the ITCZ. Hot air rises at the equator, creating a low-pressure zone. The elevated air moves toward mid-latitudes, cools, then sinks around 30° to form high-pressure areas. This circulation produces trade winds, moving from east to west, feeding the equatorial low-pressure belt (Sibisi, 2017).

21. Ferrel Cells Situated between the Hadley and Polar cells (30°–60°), airflow patterns here are more complex. Surface winds generally flow from west to east ( the westerlies ), while upper-atmosphere flow trends toward the equator (Sibisi, 2017).

22. Polar cells Cold air descends at the poles, producing high pressure . This air then moves toward lower latitudes near the surface, helping form the polar easterlies , which blow east to west (Sibisi, 2017)

23. REFERENCE LIST https://images.app.goo.gl/jMvCWNwzGed9QPWa8 https://images.app.goo.gl/ETQxCA62RrzteYWS6 https://images.app.goo.gl/kTTCMMBo1AunDPVn6 https://images.app.goo.gl/cJ6KGozyPVD1oHjq6 Fasano, G., Ferraro , L., Tomassone, L., Golzio , A., Sioni , F., & Manzato , A. (2025). Recent trends in sounding-derived indices and thunderstorm-related observations: a wider perspective over the Po Valley (No. ECSS2025-159). Copernicus Meetings. Ferraro, K. (n.d.). Atmosphere, weather and climate. SlideShare. Available at: https ://www.slideshare.net/krferraro/atmosphere-weather-and-climate . Accessed on 13 August 2025. Louthan, A. M., DeMarche , M. L., & Shoemaker, L. G. (2021). Climate sensitivity across latitude: scaling physiology to communities. Trends in Ecology & Evolution, 36(10), 931-942. Rohli , R. V., & Li, C. (2021). Atmospheric Composition, Structure, and Evolution. In Meteorology for Coastal Scientists (pp. 9-23). Cham: Springer International Publishing. Sein, Z. M. M., Ullah, I., Iyakaremye , V., Azam, K., Ma, X., Syed, S., & Zhi, X. (2022). Observed spatiotemporal changes in air temperature, dew point temperature and relative humidity over Myanmar during 2001–2019. Meteorology and Atmospheric Physics, 134(1), 7. Sibisi, N.(2017). Global Air Circulation. available at: https://www.slideshare.net/slideshow/global-air-circulation/79181950 . Accessed on 13 August 2025. Ziervogel, G., New, M., Archer van Garderen, E., Midgley, G., Taylor, A., Hamann, R., ... & Warburton, M. (2014). Climate change impacts and adaptation in South Africa. Wiley Interdisciplinary Reviews: Climate Change, 5(5), 605-620. https://doi.org/10.1002/wcc.295

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