Introduction To Weather Dynamics Introduction to Weather Video

Introduction To Weather Dynamics

Introduction to Weather - Video

What you will learn… In this unit, you will… • Describe Earth’s energy budget • Explain how energy is transferred between and among land, air and water • Describe weather-related properties of the atmosphere such as pressure and humidity • Explain how areas of high and low pressure move air and energy around the globe

Climate Widespread, long-lasting and recurring conditions of the atmosphere.

Weather (page 10) The day to day changes in the atmosphere at a particular location on Earth.

Meteorology The study of the Earth’s atmosphere and weather systems.

• Weather – What is it?

Components of Weather (see Table 1. 1, page 11) Temperature Coolness or warmth of an object (average of kinetic energy – o. C) Precipitation Any form of water that falls to Earth from atmosphere (mm or cm) Atmospheric Pressure The force of the atmosphere per square meter of surface below it (k. Pa) Humidity The amount of water vapor in the air (%) Wind Speed How quickly the air moves (km/h) Wind Direction Sky Cover The winds direction (NSEW bearings) The portion of sky that is covered by clouds

After Exam Activities • Beside your “components of weather” foldable on pg 97: – Draw and caption a picture that shows how Earth’s biosphere is made up of the atmosphere, hydrosphere, and lithosphere. Use colour to help show the difference. (Use figure 1. 2 on page 13 of your textbook. ) In the caption, describe the difference between the atmosphere, lithosphere, and hydroshpere. • Answer the following questions on page 98 of your notebook: – Pgs 4 -7: #5, 7, 12, 16, 17, 25, 26

• Sheet to complete: Part A

Earth’s Energy Budget (page 13)

Activity • Read through pgs 13 -14 in your textbook and look at figure 1. 4. • Glue the figure into your notebook on page 99. Beside and under the figure, explain what is happening in the figure. In your answer think about: – What do they mean by “Earth’s energy budget? – Where does solar radiation come from? – What happens to solar radiation when it enters Earth’s atmosphere? – How does the Earth naturally keep from over-heating?

Possible Answer • Earth’s energy budget (AKA radiation budget) is the method of how the Earth absorbs and reflects solar radiation (which comes from the sun) in order to keep the Earth from over-heating.

Types of Energy Transfer Radiation • Energy is transmitted as photons (electromagnetic radiation) • Think: The Sun!

Solar Radiation • Solar constant is defined as the amount of radiant energy that hits one square meter of the Earth’s outer atmosphere every second (1362 J/s/m 2) • Unit of energy Joule (J) • See Figure 1. 4, page 14

• Greenhouse Effect – the warming of Earth as a result of greenhouse gases (like CO 2), which trap some of the energy that would otherwise leave Earth

Terrestrial Radiation • Earth would constantly increase in temperature if it did not radiate energy back to space. • It would take approximately 25 years for the oceans to boil if no energy was emitted back to space • Terrestrial Radiation is composed primarily of infrared photons (light)

Incoming and Outgoing Radiation • About 49% of the solar energy that enters Earth’s atmosphere is absorbed by the land ocean. • About 42% is absorbed, reflected, and scattered by clouds, gases, and aerosols in the atmosphere. • About 9 percent is reflected by Earth’s surface. • Figure 1. 4

Solar Radiation Arriving at Earth’s Surface (see Figure 1. 4, page 14)

• Sheet to complete – Earth’s Energy Budget etc.

Factors Affecting Absorption of Energy • 1. The colour of a surface: – Which one reflects more light? • Snow or a farmer’s field? • Albedo - the reflectivity of a surface – Field in the summer – 20% – Field covered with snow – 70 or 80%

Factors Affecting Absorption of Energy • 2. The nature of a substance: Different substances absorb energy at different rates. – Which one will warm up more quickly? Water or sand? • The Specific Heat Capacity of a substance determines how much and how quickly it absorbs and releases energy. • Water has a much higher specific heat capacity than land air do.

Specific Heat Capacity Substance Specific Heat Capacity at 25 o. C (J/kg/o. C) Water 4186 Air 1020 Iron 444 Copper 385 Sand 290 Gold 129

Heat Sinks • Because the specific heat capacity of water is higher than that of land, water is considered to be a better heat sink. • Heat Sink: any substance that can absorb and retain energy without changing state.

Water is a good heat sink • Because there is so much water on Earth, and water is such a good heat sink, water has a great influence on weather. • Is it colder in the winter in Saskatoon or Halifax? • Is it colder in the summer in Saskatoon or Halifax? Figure 1. 5

• The energy transformations that happen between the time solar radiation is absorbed and the time it is re-emitted are what drive weather systems.

• Questions – p. 15, 1 -4 – Answers

Activity • • Dotted lines mean fold Solid lines mean cut Fold your sheet into three sections Cut the right side fold into 3 equal sections Fold cut sections in first; the cover isn’t cut Very top of outside flap title: Thermal Energy Transfer • Copy figure 1. 6 (textbook pg 16) under the title. Use 3 different colours to show the difference between conduction, convection, and radiation (see example)

On the inside cover (see example) • Thermal Energy – Energy created by the movement of particles in a substance. • Heat: Thermal energy that is transferred from one object to another

• There are three types of energy transfer. Write the headers “conduction”, “convection”, and “radiation” on each of the three flaps (see example) • Use the textbook to write a definition for each type of heat transfer under each header

Types of Energy Transfer Conduction • Requires contact between atoms; more energetic atoms collide with more energetic atoms and energy is transferred (solids with solids) • Example: Warming a pot on a stove

Types of Energy Transfer Convection • In a gas or liquid, atoms are free to move and as they warm they become less dense and rise. Atoms that are cold and denser will then descend and create a convection current. – (liquids/gas)

Types of Energy Transfer Radiation • Energy is transmitted through indirect contact (heat travelling through air or space…electromagnetic spectrum) • Ex. Sun, fire

• Definitions – Conduction, Convection and Radiation • Video – Radiation , Conduction and Convection • Newer video (7: 45)

Activity • • Glue figure 1. 7 onto page 100 of your notebook. Answer the following questions in relation to figure 1. 7 1. How does the Earth’s Atmosphere transfer thermal energy? 2. What happens to hot air? Why? 3. What do you think creates wind?

Atmospheric Pressure • Atmospheric Pressure – the pressure exerted by air on its surroundings due to the weight of the air • Measured in kilopascals (k. Pa) • At sea level, the atmospheric pressure is 101. 3 k. Pa (or 1 kg/cm 3) Copy

Factors that reduce atmospheric pressure Copy

Three factors that can reduce atmospheric pressure: • Altitude: – The higher you go, the lower the pressure • Temperature: – Warm air moves into cold air = atmospheric pressure decreases. – Cold air moves into warm air, atmospheric pressure increases. • Humidity: – The more water vapour in the atmosphere, the lighter the air is (so more humidity = less pressure) Copy

• Video (4: 28)– Atmospheric Pressure

Layers of the Atmosphere See Figure 1. 8, page 19

Layers Atmosphere Layers of of the Atmosphere • Troposphere – All water vapour is present here – All weather occurs here – From surface to ~10 km – Temperature ranges from -50°C to 50°C • Stratosphere – Ozone is present here – From 10 km-50 km – Temperature ranges -50°C to -30°C

Layers of the Atmosphere • Mesosphere – – Meteorites burn up here Some ions are present here From 50 km to 85 km Temperature ranges from -30°C to -90°C • Thermosphere – – Aurora present Some ions are present here From 90 km to 180 km (space) Temperature ranges from -90°C to over 200°C

Layers of the Atmosphere

• Video (5: 05)– Layers of the atmosphere

• To do: – Finish work sheet: • Answers – Vocabulary words: • Humidity • Dew point