Temperature

GY1432 Landscape and Climate- Ecosystem Dynamics

  • Instructor: Jörg Kaduk

Introduction to Sun's Radiation

  • The course will focus on the following:

    • Understanding how solar radiation interacts with Earth's systems.

    • Exploring the energy transfer processes in the atmosphere and biosphere.

Summary of Key Concepts (from Last Week)

  • The critical interplay between radiation and temperature:

    • Earth receives energy from the sun via radiation.

    • Radiation and Temperature Dynamics:

      • Radiation absorption leads to an increase in temperature.

      • All objects with a temperature greater than absolute zero (T > 0K) will emit radiation.

      • Stefan-Boltzman Law: Energy (E) emitted is proportional to the fourth power of temperature (E = σT⁴).

      • Wien’s Law: The wavelength of maximum emission is determined by temperature.

      • Emission of radiation results in a decrease in temperature.

  • Impact of the atmosphere:

    • The atmosphere absorbs terrestrial radiation and re-radiates it to the Earth's surface.

    • Greenhouse Effect: Long wave radiation is cycled between the surface and atmosphere, contributing to surface warming.

The Greenhouse Effect Explained

  • Incoming solar radiation is primarily shortwave.

  • A fraction of this radiation is reflected (30%, albedo α = 0.3) while the rest is absorbed, leading to surface warming.

  • Long-wave radiation emitted by the surface is absorbed by greenhouse gases, enhancing warming through down-welling long-wave radiation.

Earth’s Energy Budget

  • Breakdown of incoming and outgoing radiation:

    • Incoming shortwave solar radiation = 100 units.

    • Reflected radiation = 30 units, leading to 70 units absorbed.

    • Outgoing radiation = 100 units (including long-wave radiation lost to space and absorption by the atmosphere).

  • Energy transport between surface and atmosphere:

    • Energy is transported via conduction, convection, and latent heat release, contributing to the atmospheric energy budget.

Today's Topics

  • Understanding the temperature profile in the atmosphere.

  • Exploring global patterns of sea level temperatures.

Albedo and Climate Interactions

  • Albedo Importance:

    • The albedo effect reflects how much solar radiation is absorbed or reflected by Earth's surface.

    • Variations in albedo can significantly impact temperature regulation globally.

Solar Radiation Conditions

  • Effects of clouds on solar radiation:

    • Clear conditions vs. cloudy conditions:

      • Differences in the percentage of radiation absorbed, backscattered, and reflected.

Temperature Patterns and Their Causes

  • Variability in surface temperature patterns influences precipitation and global circulation dynamics.

  • Vertical Temperature Profile:

    • Temperature changes with altitude; understanding this profile is critical for climatic studies.

Atmospheric Pressure Profile

  • The vertical pressure profile decreases with altitude, significant for weather patterns and climate stability.

Diurnal and Seasonal Cycles

  • Diurnal cycles of temperature demonstrate fluctuations influenced by solar radiation absorption at different times of the day.

  • Seasonal temperature cycles are driven by the Earth's tilt and orbital mechanics, affecting energy absorption and distribution.

Conclusion

  • Key takeaways for upcoming lectures:

    • Understanding how energy input and output affect global temperature distributions.

    • Recognizing interactions between the atmosphere, hydrosphere, and surface, emphasizing the role of radiation and circulation in climate dynamics.

Next Steps

  • Further readings assigned to grasp advanced concepts of moisture and precipitation impacts on climate.