DO NOW Turn in Review #13. Pick up notes and Review #14.

REVIEW How does the temperature of the atmosphere change as altitude increases? WHY? How does the air pressure of the atmosphere change as the altitude increases? Why?

Solar Energy: Angle of Insolation SES5. Students will investigate the interaction of Earth systems to produce weather and climate. a. Explain how latitudinal variations in solar heating create atmospheric and ocean currents that redistribute heat globally.

EARTH’S ENERGY COMES FROM THE SUN The SUN is the source of energy in atmosphere. 30% of energy is reflected back to space (lost). 20% of energy is absorbed by atmosphere. 50% of energy is absorbed by surface – land and ocean. Energy is transferred within and between systems

SOLAR ENERGY IN DIFFERENT WAVELENGTHS Produces mostly infrared (IR) light, visible light, and ultraviolet (UV) light. Fusion in the sun’s core gives off high energy gamma rays but their frequencies are mostly only within the IR/visible light/UV spectrum by the time they reach the Sun’s surface.

SOLAR ENERGY IN DIFFERENT WAVELENGTHS During solar flares, the Sun also emits X-rays. Not all wavelengths get to the Earth’s surface through the atmosphere – some absorbed by ozone layer and ionosphere.

ENERGY ABSORBED The Earth’s surface absorbs solar energy. Absorbed by both land and water. About 70% of the solar energy that reaches Earth is absorbed by the land, oceans, and atmosphere. Energy from the Sun is absorbed and IR energy radiated back to space from the surface

ENERGY RADIATED The Earth’s surface radiates thermal (infrared, IR) energy. Some heat absorbed by land and ocean is radiated back into the atmosphere and also space. Air is heated mostly by the surface. About 70% of the solar energy that reaches Earth is absorbed by the land, oceans, and atmosphere.

ENERGY REFLECTED Some incoming solar energy is reflected back by: The atmosphere Clouds The surface of the Earth About 70% of the solar energy that reaches Earth is absorbed by the land, oceans, and atmosphere.

THERMAL INERTIA Heating of Earth’s surface is delayed. Time is required to absorb solar energy before temperature changes. Daily Delay: There is a delay between Earth's absorption of solar energy and an increase in temperature – this makes the warmest part of a day after noon.

THERMAL INERTIA Seasonal Delay: Because of a similar delay in heating and cooling of Earth’s surface, the warmest part of the year is late summer, the coldest is late winter.

ENERGY DISTRIBUTION Insolation: Exposure to the sun’s rays. The amount of solar radiation reaching a given place.

ENERGY DISTRIBUTION Angle of Insolation: angle at which the sun's rays hit the Earth. The equator receives greatest angle of insolation Sun’s rays are at 90 degrees. The energy is direct.

ENERGY DISTRIBUTION Poles receive smallest angle of insolation. Sun’s rays are less than 90 degrees. The energy is spread out over a larger area and is less direct (intense).

SOLAR ENERGY: LATITUDE Latitude determines amount of solar insolation (energy) received. Closest to equator: Has a greater angle . Has more solar insolation.

SOLAR ENERGY: LATITUDE Closer to poles: Has a lesser angle Has less solar insolation

SOLAR ENERGY: LATITUDE What would this chart look like in the southern hemisphere? Be able to answer test questions using this graph!

SOLAR INSOLATION: SEASONS The Earth’s tilt on its axis changes the amount of Solar Insolation as the Earth orbits the Sun. This is the reason for the Seasons.

SOLAR INSOLATION: SEASONS

SOLAR INSOLATION: SEASONS The amount of insolation received is primarily controlled by: Latitude (Angle of Incoming Solar Radiation) Daily Variation Seasonal Variation Latitude Variation

SOLAR INSOLATION: SEASONS The amount of insolation received is primarily controlled by: Exposure time Daily variation Seasonal Variation

SOLAR INSOLATION: SEASONS SUMMER Sun is higher in sky. Increased angle of insolation. Solar path is longer. More solar energy received.

SOLAR INSOLATION: SEASONS WINTER Sun is lower in sky. Decreased angle of insolation. Solar path is shorter. Less solar energy received

SOLAR INSOLATION: SEASONS AND LATITUDE Equator Solar path always direct east to west. More direct Sun year round. Mid-latitudes Solar path longer in summer. Solar path shorter in winter. The farther north or south of the equator, the greater the change in the solar path and the less direct the sunlight.

SOLAR INSOLATION: SEASONS AND LATITUDE Arctic/Polar regions Sun’s path circles horizon on longest day – never overhead Summer Solstice receives indirect sunlight all 24 hours. No sunlight or visible Sun during Winter.

OBSERVING ANGLE OF INSOLATION FROM EARTH Position of Sun: Based on OBSERVER’s position. Changes as the angle of insolation increases and decreases. Altitude: the angular distance of an object above the horizon (how far above your head) – 90° is at the zenith (top). Azimuth: the angular distance of an object along the horizon (where along the horizon)

Review Why does the equator receive more solar radiation consistently than locations at higher latitudes? It is closer to the Sun. It is always facing the Sun. The angle of insolation is always greater. The angle of insolation is always less.

LAB: PLOTTING THE PATH OF THE SUN The grid shows the Sun’s path at a specific location on specific date. The hours of daylight are plotted. Direct east to west which is sunrise to sunset This plot indicates Spring and Fall How was each location plotted using azimuth and altitude?

LAB: PLOTTING THE PATH OF THE SUN Plot the position (azimuth and altitude) of the Sun for each hour of the day at the summer/winter solstices and the spring/autumn equinox on the grid and connect the dots to show the path of the Sun at each season. What is the relationship between the angle of solar insolation and the observed position of the Sun in the sky?

TO DO Review #14 due tomorrow. Lab due on Monday