CSET Subtest II- 3.3 Earth’s Atmosphere (Meteorology)

What is Meteorology, and what factors affect air composition?

- Meteorology: The science of the atmosphere and weather.

- Air Composition: Varies with amounts of gases; includes nitrogen, oxygen, argon, carbon dioxide, and water vapor.

- Water Vapor: Amount depends on temperature and water availability.

- Hydrologic Cycle: Connects atmospheric processes, transferring water between the air, land, and oceans.

What are the key steps in the hydrologic cycle driven by the sun?

1. Sun Heats Water: Causes evaporation of ocean water into vapor; ice and snow can sublimate directly to vapor.

2. Evapotranspiration: Water is transpired by plants and evaporates from soil.

3. Condensation & Cloud Formation: Rising air cools, condenses vapor into clouds.

4. Precipitation: Cloud particles grow, fall as rain, snow, or ice.

5. Snow & Ice Storage: Some snow/ice becomes long-term storage in glaciers/ice caps.

6. Snowmelt & Runoff: Thawed snow flows overland; surface runoff moves to rivers and oceans.

7. Infiltration: Water seeps into soil, replenishes aquifers; some emerges as springs.

8. Groundwater Discharge: Water returns to surface, oceans, completing the cycle.

What are the primary terms and processes in the hydrologic cycle?

- Precipitation: Water that condenses in the atmosphere and falls to Earth (rain, snow, hail, etc.).

- Canopy Interception: Rain intercepted by plant foliage, later evaporates rather than reaching the ground.

- Snowmelt: Runoff generated by melting snow.

- Runoff: Water movement over land, including surface and channel runoff; may infiltrate soil, evaporate, or enter water bodies.

- Percolation: Downward movement of water through soil and rocks, forming groundwater.

- Subsurface Flow: Water flow underground in the vadose zone/aquifers; may re-emerge as springs or seep into oceans.

- Evaporation: Conversion of water to vapor, driven by solar energy; includes evapotranspiration from plants.

- Sublimation: Direct transition of ice/snow to vapor.

- Condensation: Water vapor cools to form droplets, creating clouds and fog.

What causes weather phenomena, and where do they primarily occur?

- Common Weather Phenomena: Wind, clouds, rain, snow, fog, and dust storms.

- Severe Events: Tornadoes, hurricanes, ice storms.

- Primary Layer: Weather mostly occurs in the troposphere; some weather interactions extend into the stratosphere.

- Cause: Weather results from density differences (temperature & moisture) due to solar angle variations by latitude (cooler farther from tropics).

- Temperature & Pressure: Warm surfaces heat air, causing it to expand, lowering pressure and density. Pressure gradients drive winds.

- Jet Stream: Formed by sharp temperature contrasts between polar and tropical air.

- Coriolis Effect: Earth's rotation curves air flow, enhancing wind patterns.

- Prediction Limits: Small changes can have large effects due to atmospheric chaos, limiting forecast accuracy.

- Sun & Oceans: Sun heats ocean water, causing evaporation; moisture spreads, cooling nearby land.

How does differential heating cause land and sea breezes?

- Differential Heating: Land heats and cools faster than water; water retains and releases heat more gradually.

- Land Breeze: At night, land cools quickly, chilling nearby air. Warmer air over the sea rises, and cool air from land moves in to replace it. Occurs in late night and early morning.

- Sea Breeze: During the day, land heats faster, warming the air. Rising warm air over land draws in cooler sea air. Occurs in the afternoon and evening.

- Result: Alternating onshore and offshore breezes in coastal areas, driven by daily temperature cycles.

1What causes mountain and valley breezes?

- Differential Heating: Peaks receive sunlight first and heat faster than valleys, causing air temperature differences.

- Valley Breeze (Daytime): Sun warms mountain slopes, making warm air rise; cooler valley air flows up to replace it.

- Mountain Breeze (Night): Valley releases heat in the afternoon; cooler, denser air flows downslope from the peaks into the valley, partly due to gravity and convection.

- Effect: Cyclic airflow based on day-night temperature differences between slopes and valleys.

What are El Niño and La Niña, and how do they differ?

- El Niño: Warm sea surface temperatures (≥0.5°C above normal) in the central tropical Pacific; replaces cold, nutrient-rich Humboldt Current with nutrient-poor water, affecting fish populations.

- La Niña: Cooler-than-normal sea surface temperatures in the eastern equatorial Pacific, often enhancing Atlantic cyclone activity.

- Cycle: La Niña frequently follows a strong El Niño event.

- Impact: Significant climate effects globally, influencing oceanic and atmospheric patterns.