WEATHER AND CLIMATE
What is the atmosphere? What is the difference between weather and climate? What elements influence climate? Could you explain what the wind is? What are the Earth s main climate? What is a natural landscape?
TOPICS 1. The atmosphere 2. Weather and climate 3. The elements of climate Temperature Precipitations Atmospheric pressure Wind
1. The atmosphere The atmosphere is the layer of gases that surround the Earth and makes life possible on the planet. It composition is nitrogen, oxygen, argon, carbon dioxide, hydrogen, ozone, methane and water vapour. The atmosphere is divided into layers: troposphere, stratosphere, mesosphere, thermosphere and exosphere.
1. The atmosphere
ACTIVITIES 1. The atmosphere is composed by o o o o o o o o
ACTIVITIES 2. Make a drawing of the layer of the atmosphere and write the main characteristic of each layer.
2. Weather and climate Weather is a result of atmospheric conditions at a certain place and time. For example, if we say it is raining in Málaga today, we are talking about the weather. Climate is the result of average atmospheric conditions in certain region over a long period of time. For example; if we say that Málaga always has hot summers, we are talking about climate. Meteorology is the study of the atmospheric phenomena. Climatology is the science that studies the climate.
ACTIVITY 3. Say if we are talking about weather or climate and if there is any incorrect expression: a) It rains a lot in spring in my village. b) It s very hot and sunny today. c) Today it s a good climate in Málaga. d) In La Coruña always rains but today it s sunny.
ACTIVITY 4. Discuss the questions in pairs: a) Do any of your normal activity depend on the weather? Which ones? b) Which people are especially interested in the weather forecast? Why? c) What s the weather like today? Is it typical of the climate in your region?
3. The elements of climate To define a climate we have to know the following elements:
3. The elements of climate We define climates according to their elements: temperature, precipitation, atmospheric pressure and wind. These elements are influenced by factors such as latitude, altitude, land and sea distribution, ocean currents, etc.
3. The elements of climate TEMPERATURE Temperature is the amount of heat in the air. We measure it with a thermometer. We express it in degrees centigrade ( ⁰C)
TEMPERATURE In maps, the lines that links points with the same temperature are called isotherm. 3. The elements of climate
3. The elements of climate TEMPERATURE Factors that affect temperature: Latitude Altitude Proximity to the sea Ocean currents Temperatures decrease from the Equator towards the poles. Temperature falls as altitude increases. On average, for every 1.000 m. of altitude, the temperature drops by 6 ⁰C. The sea heats up and cools down more slowly than the land. Because of that, temperatures are milder in areas close to the sea. Warn ocean currents produce higher temperatures in nearby coastal regions. Cool ocean currents have the opposite effect.
3. The elements of climate Latitude and temperature
3. The elements of climate Altitude and temperature
3. The elements of climate Ocean currents and temperature
3. The elements of climate Temperature According to temperature, the Earth is divided in three climates zones: Tropical zones Temperate zones Polar zones Lies between 0⁰ and 30⁰ latitude north and south (between the tropics). Temperatures are always high. The mean annual temperature is over 20 ⁰C. Lie between 30⁰ and 60⁰ latitude north and south (between the tropics and the polar circles). Temperatures vary according to the season. The mean annual temperature varies between 0 ⁰C and 20⁰C Lie between 60 ⁰C and 90 ⁰C latitude north and south. Temperatures are low all year round. The mean annual temperature does not rise above 0 ⁰C.
3. The elements of climate The three climates zones:
ACTIVITIES 5. Explain the meaning of the following word: o Temperature o Thermometer o Isotherm
ACTIVITIES 6. Which factors does temperature depend on? o o o o
ACTIVITIES 7. Look at the map. It is the same temperature in Great Britain than in Kamchatka Peninsula? Why?
3. The elements of climate Precipitation Precipitation is water from the atmosphere that falls onto the Earth s surface in the form of rain, snow, sleet or hail. The atmosphere contains water vapour. The amount of water vapour in the air is called humidity. Low humidity means that the air is dry. High humidity means that the air is moist.
3. The elements of climate Precipitation We measure humidity with a hygrometer. We express it in per cent (%).
3. The elements of climate Precipitation When humid air rises, it cools and produces condensation, forming small droplets of water, which form clouds. For the precipitation to occur, the droplets must become bigger and heavier. When this happens they fall (precipitation) onto the Earth s surface.
3. The elements of climate Precipitation We measure the precipitations with a rain gauge or pluviometer. We express it in square metres (L/m2) or in millimetres (mm).
3. The elements of climate Precipitation In maps, the lines that links points with the same precipitation are called isohyets. The amount of precipitation varies from one zone to another, depending on factors like altitude, latitude, and proximity to the sea.
TYPES OF RAIN
EL CICLO DEL AGUA http://www.iesmariazambrano.org/departamentos/flasheducativos/hidrologico.swf
ACTIVITIES 8. Match terms of the columns and explain their meaning. Temperature Precipitation Humidity Water vapour Rain gauge / pluviometer Degrees centigrade (⁰C) Per cent (%) Isohyets Square metres (L/m2) / millimetres (mm) thermometer hygrometer Isotherm
3. The elements of climate Atmospheric pressure It is the atmosphere s weight on the Earth s surface. We measure pressure with a barometer in millibars (mbar). Normal pressure (at sea level) is 1.013 mbar. We show pressure on maps using lines called isobars.
(H) High pressure areas or Anticyclones Areas where pressure is more than 1.013 mbar. They are shown on maps by circular isobars, where pressure increases toward the centre, which is marked by the letter H. Produce stable weather conditions. The air is cool and therefore heavier, so it descends. The air is also dry, so there is no precipitation. (L) Low pressure areas or Depressions Areas where pressure in below 1.013 mbar. They are also shown on maps by circular isobars, but the pressure decreases toward the centre, marked by the letter L. Produce unstable weather conditions, with a lot of cloud and precipitations. The air is warm and humid. It is lighter and so it rises. At it rises, the air cools and can produce rain.
Map of Isobars
3. The elements of climate Wind It is air that moves from areas of high pressure to areas of low pressures. We measure wind speed with an anemometer in metres per second (m/s) or kilometres per hour (Km/h).
3. The elements of climate Wind A weather vane show the direction of the wind. Winds are named after the direction they come from. For example, a wind from the north is called a north wind, although it is moving south.
ACTIVITIES 9. Say if the following sentences are true or false. Correct the false ones. a) We measure atmospheric pressure with the anemometer. b) Atmospheric pressure is expressed in m/s or km/h. c) The barometer is used to measure the wind speed. d) We know the wind direction thanks to the weather vane.
ACTIVITIES 10. Make a short weather forecast.
3. The elements of climate Some kind of winds always blow in the same direction:
THE END By José Luis Alcaide Juárez Geography & History teacher IES Puerta de la Axarquía