Chapter 3Chapter 3The Changing The Changing

WeatherWeather

Chapter 3 TermsChapter 3 Terms

CondensationCondensation

Orographic Orographic CondensationCondensation

Convectional Convectional CondensationCondensation

Frontal CondensationFrontal Condensation

High Pressure SystemHigh Pressure System

Low Pressure SystemLow Pressure System

ClimateClimate

Precipitation

Weather

Air Masses

Continental Artic

Maritime Tropical

Maritime Polar

Front

Ocean Currents

Gulf Stream

Labrador Current

Weather Radar Stations

Meteorologists

Radiosonde

Conditions leading to Conditions leading to CondensationCondensation

SnowSnowSnow forms Snow forms when water when water vapour vapour condenses at a condenses at a temperature temperature below the below the freezing pointfreezing point

Read pp. 33 - 36

Snow Snow StormStorm

For a For a snowstorm to snowstorm to happen – it happen – it needs two needs two things…things…Snow Snow WindWind

Low & High Pressure Low & High Pressure SystemsSystems

Low Pressure System – Air rising over a warm surface

High Pressure System – Cool air sinks towards the surface, pushing the air underneath away

Why we get wind…Why we get wind…

Air over the North and South Poles sink, because it is cold, Air over the North and South Poles sink, because it is cold, producing an area of high pressureproducing an area of high pressure

Air over the equator rises because it is hot, producing an area Air over the equator rises because it is hot, producing an area of low pressureof low pressure

The earth rotates on its axis once every day, so that a point on The earth rotates on its axis once every day, so that a point on the equator travels approximately 40000 km in 24 hours – a the equator travels approximately 40000 km in 24 hours – a velocity of nearly 1700km/hrvelocity of nearly 1700km/hr

Winds in the northern hemisphere blow counterclockwise into Winds in the northern hemisphere blow counterclockwise into a low pressure area and clockwise out of a high pressure areaa low pressure area and clockwise out of a high pressure area

An area between high and low pressure feels the effects of An area between high and low pressure feels the effects of both circulationsboth circulations

High winds can develop when areas of very high and very low High winds can develop when areas of very high and very low pressure come close togetherpressure come close together

Questions… Page 37 #’s 1 - 4

Factors which affect Factors which affect ClimateClimate

Climate – average conditions of temperatureClimate – average conditions of temperature

Precipitation – rain, snow, humidity, pressure Precipitation – rain, snow, humidity, pressure and windand wind

Weather – conditions of the atmosphere over Weather – conditions of the atmosphere over a short period of timea short period of time

They can all be demonstrated on a They can all be demonstrated on a climate graph…climate graph…

Climate Climate GraphGraph

Consists of…Consists of…Temperature – on Temperature – on left of graph – shown left of graph – shown by a line graphby a line graphPrecipitation – on Precipitation – on right of graph – right of graph – shown by a bar graphshown by a bar graphMonths of the year – Months of the year – on bottom of graphon bottom of graph

Climate Graph Assignment

Factors which influence Factors which influence the climate in Atlantic the climate in Atlantic

CanadaCanada Latitude – because of the shape of the earth’s surface, there Latitude – because of the shape of the earth’s surface, there

are parts of Atlantic Canada which receive more intense are parts of Atlantic Canada which receive more intense sunshine than otherssunshine than others

Air Masses – affect the climate because they take on the Air Masses – affect the climate because they take on the temperature and humidity characteristics of the areas in temperature and humidity characteristics of the areas in which they originatewhich they originate

Ocean Currents – the waters of the world’s oceans are Ocean Currents – the waters of the world’s oceans are constantly in motion. Tides move the water up and down constantly in motion. Tides move the water up and down while currents move water from place to place. The major while currents move water from place to place. The major ocean currents have considerable influence on climate.ocean currents have considerable influence on climate.

Proximity to Water – Areas very close to large bodies of water Proximity to Water – Areas very close to large bodies of water stay cooler in summer and warmer in winter than areas inlandstay cooler in summer and warmer in winter than areas inland

Elevation – As height increases, temperatures decrease, Elevation – As height increases, temperatures decrease, largely because air is so much thinner at high altitudeslargely because air is so much thinner at high altitudesRead pp. 37 – 41

Questions…Page 42

Examining Examining WeatherWeather

Land & Sea – weather Land & Sea – weather observers note and observers note and transmit information transmit information about the state of the about the state of the atmosphereatmosphereFrom the Air – use From the Air – use radar to detect, locate radar to detect, locate and measure the and measure the amount of amount of precipitation in cloudsprecipitation in cloudsFrom Space – From Space – weather satellites are weather satellites are used to make long-used to make long-term weather term weather forecastsforecasts

Weather Radar Station

Read pp. 43 – 45, Questions…Page 46Read pp. 46 – 47, Questions…Page 48