TELEMATIC TEACHING PROJECT Climate and Weather glenn@kns.wcape.school.za

GLOBAL AIR CIRCULATION High and Low pressures Circulation patterns

HIGH AND LOW PRESSURES

GLOBAL AIR CIRCULATION PATTERN Polar high Very cold Decending air HIGH PRES Warm & cold air meet LOW PRES Western winds Tropical easterlies Very hot Ascending air LOW PRES Air from Equator sinks HIGH PRES Winds deflect to the RIGHT in NH and to the LEFT in SH

MID LATTITUDE CYCLONES Cold & warm fronts Stages Weather changes

MID LATTITUDE CYCLONES: CONCEPTS WARM FRONT COLD FRONT

MIDLATTITUDE CYCLONE: DEVELOPMENT 1 INITIAL STAGE 2 DEVELOPMENT STAGE 3 MATURE STAGE 4 OCCLUSION FAMILY OF CYCLONES

Wind rotation clockwise MID-LATTITUDE CYCLONE Cold front Warm sector Warm front Cold sector Isobar L Wind rotation clockwise

Weak pressure gradient WEATHER CHANGES COLD FRONT Weak pressure gradient Isobars far Cold front NW Wind SW Wind Warm front Steep pres gradient Isobars close

WEATHER CHANGES: COLD FRONT M o v e m e n t o f c y c l o n e NW-wind High temp Few/no clouds No precipitation HP SW-wind Low temp High cloud cover Precipitation LP LP

TROPICAL CYCLONES Characteristics Stages How managed

TROPICAL CYCLONES CHARACTERISTICS Equator/Ewenaar From EAST to WEST EYE No wind, rain & Clouds OCCUR Tropics Ocean Further - 5° Away from equator DESTRUCTION Storm winds Torrential rain Flooding DISSIPATES No Moisture No warm air Friction Turns EAST at 30°

TROPICAL CYCLONE: DEVELOPMENT INITIAL pressure ABOVE 1000 hPa IMMATURE Pressure BELOW 1 000 hPa MATURE pressure WELL BELOW 1 000hPa DISSI-PATION pressure RISES

TROPICALCYCLONE - MANAGEMENT

TROPICAL CYCLONES NAME Alphabet Andrew Bonny Carl Debora ORIGEN In tropics OCEANS Not nearer than 5° from equator MOVEMENT From E na W Away from Equator Turns east at 30° DESTRUC- TION Storm winds Very hard rain Flooding IN EYE No : Wind Clouds Rain WEATHER Before eye During eye After eye DISSIPA- TION Over land No Moisture No Warm air Friction MANAGED Sand bags Early warning Track storm Services Inform people Evacuation

EXAMINATION QUESTION Coriolis force Warm water Moisture Land Tropical easterlies Coriolis force Warm water Moisture Land No warm water Friction Give ONE similarity between Hurricanes and Tropical cyclones on the map. Explain the point of origin of both hurricanes and tropical cyclones on the map. Why do these cyclones move from east to west? Why do tropical cyclones weaken as they move over Madagascar. Why is the impact of tropical cyclones more severe in developing countries?

REGIONAL CLIMATE Line thunderstorms Berg winds

WARM MOIST AIR COLD DRY AIR LINE THUNDERSTORMS MOI STURE FRONT Cold Benguela Warm Mozambique WARM MOIST AIR COLD DRY AIR H H

HEIGHT OF INVERSION

High pressure in interior SOUTH AFRICAN BERGWIND Anti clockwise circulation H High pressure in interior Danger: Veldfires Descending air heated Warm dry wind at coast L Low pressure over sea

EXAMINATION QUESTION SUBSIDES - WARMER WARM & DRY – FROM INTERIOR DRY Name the high pressure cell visible on the diagram. During what season do berg winds affect the weather of South Africa? How does the wind in the diagram affect the weather along the coast of SA? Explain why these weather conditions mentioned in question 3 occur. Name the environmental hazard associated with berg wind conditions. How are berg winds terminated (ended)?

VALLEY CLIMATES Aspect Inversions

VALLEY CLIMATES ASPECT (SH) PERPENDICULAR NORTH SOUTH WARMER NO SNOW SHADOW ZONE SNOW COLDER

I N V E R S I O N S WARM AIR INSOLATION Radiation faster if no clouds During day – land heated In night surface cools off Radiation faster if no clouds Air close to surface- cooler Cold air decends WARM AIR POLUTED AIR TRAPPED

URBAN CLIMATES Characteristics of urban climate Heat Islands

CHARACTERISTICS OF CITY CLIMATES

Why are cities warmer than rural areas? MOTORS CONCRETE INDUSTRIES GLASS BUILDINGS

EXAMINATION QUESTION What is a heat island? Which part of the city is experiencing the highest temperature? How have peoples lives been changed by heat islands. Whet can be done to reduce high temperatures in cities?

SYNOPTIC WEATHER MAPS Station models Interpretation

 WEATHER STATION MODEL 20 18 N S E W WIND DIRECTION TEMPERATURE DEW POINT TEMPERATURE WIND SPEED 10 Knots 15 Knots 5 Knots

SYNOPTIC WEATHER MAPS

TRANSITIONAL PAGE

TRANSITIONAL PAGE