Lesson 6: Weather and Climate Topic Revision

Lesson 6: Weather and Climate Topic Revision

• 1.
  Weather and Climate ARevision of Topics Mr. T. Tonna
• 2.
  Index  Topic One:Depressions  Topic Two: Anticyclones  Topic Three: Tropical Storms – Case Study: Hurricane Katrina, 2005  Topic Four: Micro-Climate of an Urban Area  Topic Five: Climate of The Maltese Islands  Class Quiz- Who Wants to be a Millionaire? Mr. T. Tonna
• 3.
  Depressions  Depressions arelow pressure systems that form in the mid-latitude region (30 -60 N/S) when warm air meets cold air.  When this occurs the warm air is forced above the colder air. It then cools and clouds form which produce rain. Mr. T. Tonna
• 4.
  Mr. T. Tonna WarmFront Cold Front Occluded Front The Beginning of the depression The End of the Depression When the warm and cold fronts join.
• 5.
  Mr. T. Tonna
• 6.
  Anticyclones  Anticyclones areformed from an area of high pressure.  They tend to bring clear, settled weather.  In an anticyclone, air descends and pressure increases. This brings very light winds (which blow outwards from the centre in a clockwise motion), clear skies and dry conditions (because the air is descending and warming up, there are no clouds and no rain). Mr. T. Tonna
• 7.
  Mr. T. Tonna Winter Anticyclones Summer Anticyclones Dryand bright with very little cloud. Very little cloud Sun low in the sky, so cold conditions. Dry with light winds Clear evening skies mean that nights can be very cold. Sun high in the sky, so hot and sunny Early morning frost and fog may last all day. Cloudless skies at night allow heat to escape, so nights can be cool. Extensive low cloud or fog may produce overcast or ‘gloomy’ conditions. Risk of thunderstorms at end of ‘heat wave’ conditions Early morning dew and mist.
• 8.
  Tropical Storms  Tropicalstorms are areas of extremely low pressure, they produce violent weather with high winds, thick cloud and torrential rain.  There are three main criteria needed for a tropical storm to develop:  Warm Tropical Oceans (Temperature of 24 C or more)  Late Summer early Autumn where sea temperature is optimum.  In Certain Latitudes: 5 -20 North and South. Mr. T. Tonna
• 9.
  Mr. T. Tonna
• 10.
  Hurricane Katrina (2005) Hurricane Katrina formed as Tropical Depression over the south-eastern Bahamas on August 23, 2005. It grew into a Category 5 Hurricane.  New Orleans had: Winds over 175miles per hour (over 280km/h); An estimated 80 percent of New Orleans was under water, up to 20 feet deep in places; The centre eye had a low pressure of 920 mbar.  1 million people homes destroyed $81 billion in damages.  Oil facilities were damaged and as a result petrol prices rose in the UK and USA.  Total Estimated Damages exceeded $150 billion in Louisiana and Mississippi alone. Mr. T. Tonna
• 11.
  Micro-Climate of anUrban Area  A Micro-climate is a local atmospheric zone where the climate differs from the surrounding area.  Human activity has a big influence on the climate of an urban area.  Climate in Urban Areas are affected by human factors such as pollution, the colour of buildings, people themselves and factories etc.  An urban heat island (UHI) is a metropolitan area that is significantly warmer than its surrounding rural areas due to human activities. Mr. T. Tonna
• 12.
  Mr. T. Tonna
• 13.
  Climate of theMaltese Islands  The climate is typically Mediterranean, with hot, dry summers, warm and sporadically wet autumns, and short, cool winters with adequate rainfall. Nearly three-fourths of the total annual rainfall of about 600 millimetres (24 inches) falls between October and March; June, July, and August are normally quite dry.  The Rainfall and Temperature are highest in July and lowest in December.  Malta is extremely windy with only 7.7 % days considered as calm. Most common wind is the north-westerly ‘il-Majjistral’ (19% of the days in a year). Mr. T. Tonna
• 14.
  Mr. T. Tonna
• 15.
  Quiz Time Mr. T.Tonna