Weathering the Storm

Weathering the Storm

Learning Objectives:

• Distinguish the difference between weather and climate

  • Weather is the day-to-day changes in the atmosphere, while climate is long term, and is the overall pattern of weather averaged over 30 years.
    
    

• Explain why different parts of NZ and the world experience different climates (Describe and explain the broad climatic patterns of NZ with examples*)

  • NZ Climates

    • Auckland

      • Experiences convectional rainfall due to sun and lack of mountains

      • Mild climate

      • Proximity to ocean regulates temperatures

    • Alexandra

      • Very dry

      • Hot in summer, cold in winter

      • Continental climate

      • Isn't affected by ocean temperatures

      • Rain shadow area of the Southern Alps

    • Hokitika

      • Receives a lot of orographic rainfall as it is on the western side of the Alps

      • Has the ocean to the left and mountains to the right

    • Christchurch

      • Has little rain due to the shelter of the Southern Alps

      • Colder temperatures

      • Average sunshine hours

    • Wellington

      • Windy, funnelled through the Cook Strait

      • Relief of surrounding mountains

    • Nelson

      • Ocean proximity prevents extreme temperatures
        
        

• Study how we can predict and measure the weatherEvaluate the evidence for and against climate change and study the impact of a changing climate*

  • Evidence for:

    • Baffin Island, Canada:

      • Used to have solid, blue ice, but now due to climate change, these have begun to melt and become less like solid ice, becoming more slushy and ice-cream like.

    •  Palau:

      • Islands have been destroyed by climate change

      • 10 years ago, these islands would have been inhabitable, but due to climate change, some of them have no longer ceased to exist.

    • China:

      • China is one of the largest polluting countries in the world. The coal consumption in Beijing and the area surrounding the city is more than the entire country of the United States of America combined. People’s lives have been massively affected by the smog - almost everyone wears masks, and there are concerns of cancer affecting people’s lives.

  • Evidence against:

    • El Nino
      
      

• Analyse the causes and effects of an extreme weather event

Key Content and Terms

• Weather and Climate

  • Weather and Climate

    • Weather

      • The day-to-day changes in the atmosphere

      • The elements of weather are:

        • Temperature

        • Precipitation

        • Humidity

        • Cloud cover

        • Sunshine

        • Air pressure

        • Wind direction

        • Wind speed

        • (WHAT’S CP)

    • Climate

      The overall pattern of weather, based on an average over 30 years

      The elements of climate are:

      • Precipitation

        • Refers to moisture in the atmosphere returning to Earth and takes the form of rain, hail, sleet, snow or fog

      • Sunshine

        • Refers to the amount of incoming solar radiation

      • Temperature

        • Refers to the degree of heat of the atmosphere

      • Wind

        • Refers to the movement of air from high to low pressure areas

    • Controls of Climate

      • Latitude

      • Altitude

      • Size of landform and proximity to oceans

      • Relief 

      • Wind and pressure systems

      • Sea temperature and currents
        
        

    • Latitude

      • Horizontal lines drawn on the Earth to help us locate places

      • Measured in degrees north and south of the equator (equator is 0)

      • The closer you are the the equator, the stronger the sunlight you receive will be. The further away from the equator you are, the weaker the sunlight will be. This is because due to the slant of the Earth, sunlight doesn't concentrate fully onto one area, and is spread across a larger area.
        
        

    • Altitude

      • Altitude is the distance above sea level

      • Higher altitude typically means lower temperature
        
        

    • Relief

      • Relief means the shape of the land.

    Refers to valleys, hills, mountains, flat plains etc.
    Reasons for differing climates in Auckland, Alexandra, Hokitika, Christchurch, Wellington, Nelson and Mount Cook

    • NZ Climates

      • Auckland

        • Experiences convectional rainfall due to sun and lack of mountains

        • Mild climate

        • Proximity to ocean regulates temperatures

      • Alexandra

        • Very dry

        • Hot in summer, cold in winter

        • Continental climate

        • Isn't affected by ocean temperatures

        • Rain shadow area of the Southern Alps

      • Hokitika

        • Receives a lot of orographic rainfall as it is on the western side of the Alps

        • Has the ocean to the left and mountains to the right

      • Christchurch

        • Has little rain due to the shelter of the Southern Alps

        • Colder temperatures

        • Average sunshine hours

      • Wellington

        • Windy, funnelled through the Cook Strait

        • Relief of surrounding mountains

      • Nelson

        • Ocean proximity prevents extreme temperatures

      • Mount Cook

        • Mount Cook is very high up in altitude, and therefore experiences much lower temperatures

        • For every 1000m above sea level, temperature decreases by 1^oC
          
          

  • Different types of rainfall

    • Relief (Orographic) rainfall

      • When warm, moist air meets a mountain barrier, it is forced to rise. As air rises, it cools, condenses and releases some of its moisture as rain.

      • In NZ, due to the prevailing SW wind, this generally happens on the western sides of mountains

      • The now dry air amass moves over the mountain range and warms as it descends, creating a rain shadow

      • Frontal (Cyclonic) rainfall

        • Warm, moist air comes and meets cool air. The warm air is forced to rise over the cool air and forms clouds that cause rain

        • Most of the rain in north + east NZ is frontal rain

        • The reason these air masses cannot mix is due to their different densities - lighter warm air will rise over colder dense air

      • Convectional rainfall

        • During the day, hot sunshine from clear skies forces warm surface air to expand, rise and carry moisture up into the sky

        • If the ground is wet/heavily vegetated, rapid evaporation will occur, making the rising air extremely moist

        • Eventually, the buildup of rising air reaches a cooler temperature as it is forced up, which causes rain and storms

        • Most common in equatorial areas (also seen in Auckland in summer)
          
          

      • Rain shadow

        • The drier side of the mountain - this area is dry as all the moisture in the air has been dropped on the other side of the mountains
           

      • The main climatic zones

        • Tropical climate

          • hot, humid and rainy climates found mostly between the tropics of Cancer and Capricorn

        • Temperate climate

        • environments with moderate rainfall spread across the year or portion of the year with sporadic drought, mild to warm summers and cool to cold winters

        • Polar climate

        • consists of cool summers and very cold winters, which results in treeless tundra, glaciers, or a permanent or semi-permanent layer of ice
          

• Greenhouse effect

  • The process that occurs when gases in the atmosphere trap the Sun's heat

  • As more pollutants are released into the atmosphere, these form a blanket around the Earth which makes it harder for heat to escape - this causes global warming
    
    

• Global warming

  • Global warming describes the current rise in the average temperature of Earth's air and oceans
    
    

• Measuring of weather

  • Barometer

    • Used to measure atmospheric pressure

  • Thermometer

    • Measures temperature

  • Anemometer

    • Measures wind speed

  • Rain gauge

    • Used to measure amount of precipitation
      
      

• El Nino

  • Weather pattern

  • Ocean waters along South America and California warm above normal temperatures. Many rain clouds form over this warm part of the ocean and move inland, dumping more rain than usual in South and Central America and the United States.

  • Normally, strong winds along the equator push the warm surface water near South America westward toward Indonesia. When this happens, the cooler water underneath rises up toward the surface of the ocean near South America.

• However, in the fall and winter of some years, these winds are much weaker than usual. They actually blow the other way (toward South America instead of Indonesia) in October. So the warm surface water along the equator piles up along the coast of South America and then moves north towards California and south toward Chile.
  
  

• Interpreting weather maps; Different types of fronts

  • Isobars

    • Lines drawn on maps to connect areas of equal pressure

    • Measured in millibars (mb)

    • Measured by barometer

  • Millibars

    • The amount of weight or pressure the air exerts on the ground at the point at which they are measured

  • Anticyclones

    • Areas of high pressure marked on weather maps

    • H ‒> Brings fine and settled weather, warm temperatures

  • Depressions/Cyclones

    • Areas of low pressure marked as L ‒> Brings wet and windy weather

  • Fronts:

    • A front is a boundary between two different air masses and along fronts there is often stormy weather, sharp temperature changes and rapid shifts in wind direction

    • Warm front

      • Warm air pushes into cold air, rises up and gently forced upwards, producing widespread precipitation

    • Cold front

      • Warm air meets a wall of cold air, is abruptly forced up

      • Causes severe, active and intense weather

• Continental and maritime climates

  • Continental climate

    • A relatively dry climate with very hot summers and very cold winters, characteristic of the central parts of Asia and North America.

    • This is because they are too far inland to be affected by the ocean water, which generally helps land cool down and warm up.

  • Maritime climate

    • Influenced by nearby ocean - Due to its proximity to the ocean, a maritime climate experiences very cool winters and very cool summers, with a narrow range of temperatures
      
      

Hurricane Katrina