2: Solar and Infrared Radiation
- Page ID
- 9539
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)Solar energy powers the atmosphere. This energy warms the air and drives the air motion you feel as winds. The seasonal distribution of this energy depends on the orbital characteristics of the Earth around the sun. The Earth’s rotation about its axis causes a daily cycle of sunrise, increasing solar radiation until solar noon, then decreasing solar radiation, and finally sunset. Some of this solar radiation is absorbed at the Earth’s surface, and provides the energy for photosynthesis and life. Downward infrared (IR) radiation from the atmosphere to the Earth is usually slightly less than upward IR radiation from the Earth, causing net cooling at the Earth’s surface both day and night. The combination of daytime solar heating and continuous IR cooling yields a diurnal (daily) cycle of net radiation.
- 2.0: Orbital Factors
- This page covers Johannes Kepler's laws of planetary motion, highlighting Earth's elliptical orbit and its sidereal period. It explains the impact of Earth's axial tilt on seasons, solar declination, and temperature differences despite proximity to the sun. Key concepts like perihelion, aphelion, and seasonal dates are discussed, along with calculations for solar angles and twilight phases.
- 2.1: 2.2. Flux
- This page covers the concept of flux density, highlighting its definition as the transfer of a quantity per unit area over time. It includes examples of different flux types like mass and heat, along with their directional components in three dimensions.
- 2.2: Radiation Principles
- This pages provide an in-depth exploration of radiation, covering its propagation, emission, and interaction with materials. Key topics include electromagnetic waves, blackbody radiation laws (Planck's, Wien's, Stewart-Boltzmann), and solar irradiance calculations impacted by angles of incidence. The text highlights the complexities of radiation properties like reflectivity and absorptivity, and introduces concepts such as extinction and Beer’s law.
- 2.3: Surface Radiation Budget
- This page describes net radiative flux (F*), detailing its components of solar and longwave radiation at the Earth's surface. It explains how downwelling solar radiation is influenced by atmospheric transmissivity and albedo, while longwave radiation is calculated with the Stefan-Boltzmann law.
- 2.4: Actinometers
- This page covers actinometers and radiometers used to measure electromagnetic radiation in meteorology, detailing pyranometers, pyrheliometers, and pyrgeometers for solar and infrared radiation. It explains bolometers and photometers as sensing tools, discusses methods for solving differential equations in meteorology, and stresses the significance of innovative solutions and result verification. The page also includes examples of irradiance calculations and various solution-finding methods.
- 2.5: Review
- This page explains how solar heating and nighttime cooling affect temperature and humidity due to Earth's rotation and orbit. It details the processes of short-wave radiation heating and infrared radiation emission, leading to a net radiation effect at specific locations while maintaining global radiative equilibrium. The page also discusses the role of satellites and introduces tools like actinometers and radiometers used for measuring radiation, particularly in remote sensing applications.
- 2.6: Homework Exercises
- This page discusses exercises on solar radiation and its interaction with the Earth's atmosphere, focusing on topics such as Planck's Law, solar irradiance, land-use impacts on albedo, and climate effects from changes in orbital parameters. Key concepts include the influence of these factors on net radiation, insolation values, and environmental conditions.
Thumbnail: Note the two smaller eruptions before the big one. The Sun’s upper atmosphere (corona) is shown here. (CC BY-SA 3.0 Unported; Patrick McCauley/From Quarks to Quasars/SDO via Wikipedia).