test 4

• Climatology

  The study of climate and its effects
• Climatology

  Iklim
• AIB 1012

  Course code
• DR. SHEEBA NETTUKANDY CHENOLI

  Senior Lecturer, Department of Geography, [e-mail]
• DR. FADZIL MOHD NOR

  Lecturer, Institute of Ocean and Earth Sciences, [e-mail]
• Factors Controlling Temperature Distribution

  • The latitude of the place
  • The altitude of the place
  • Distance from the sea
  • The airmass circulation
  • The presence of warm and cold ocean currents
  • Other local aspects (e.g. topography)
• Solstice

  The time when the sun reaches its highest or lowest point in the sky
• Equinox

  The time when the sun crosses the plane of the earth's equator, making night and day of approximately equal length all over the earth
• Distribution of the annual cycles of absorbed solar radiation (ASR)

  • ASR differences between JJA and DJF show in excess of 200 Wm-2, highlighting the dominance of the solar input
  • In tropics the differences between DJF and JJA are related to changing convection patterns in mid latitudes, this is more a function of temperature
• Global distribution of surface air temperature in the month of July
• Global distribution of surface air temperature in the month of January
• Radiation and Temperature variation

  • The daily variation in air temperature is controlled by incoming energy (primarily from the sun) and outgoing energy from the earth's surface
  • Where incoming energy exceeds outgoing energy (orange shade), the air temperature rises
  • Where outgoing energy exceeds incoming energy (blue shade), the air temperature falls
• Malaysia (diurnal air temperature)

  • Minimum temperature usually before sunrise
  • Maximum temperature usually in late afternoon
• Mean daily temperature

  The average temperature of a place on any one day
• Daily temperature range

  The difference between the maximum and minimum temperatures recorded in a day
• Mean monthly temperature

  The average temperature of a place in a month
• Mean annual temperature

  The average temperature in a place within a year
• Being in the equatorial tropics, the temperature in Kuala Lumpur does not vary much from month to month
• Annual range of temperature

  The difference between the average temperature of the warmest and coldest months
• Temperature anomaly

  The departure from the average temperature, positive or negative, over a certain period (day, week, month or year)
• Temperatures are obtained from surface and offshore weather stations, or inferred from meteorological satellite data
• Anomalies can be calculated for surface and upper-air atmospheric temperatures or sea surface temperatures
• Meteorological requirements for temperature measurements

  • The air near the Earth's surface (air temperature)
  • The surface of the ground
  • The soil at various depths
  • The surface levels of the sea (SST) and lakes
  • The upper air
• Instruments for measuring air temperature

  • Liquid-in-glass
  • Bimetallic
  • Electrical
  • Radiometer
  • Radiometer
  • Electrical
  • Bimetallic
  • Stevenson screen
• Radiation shields

  • Provide an enclosure with an internal temperature that is both uniform and the same as that of the outside air
  • Completely surround the thermometers and exclude radiant heat, precipitation and other phenomena that might influence the measurement
  • Screens with forced ventilation, in which air is drawn over the thermometer element by a fan, may help to reduce biases when the microclimate inside the screen deviates from the surrounding air mass
• Maximum temperature thermometer

  Mercury-in-glass thermometer with a constriction in the neck, which prevents the mercury from returning to the bulb as the temperature falls
• Resistance Temperature Detector (RTD)


  A sensor whose resistance changes as its temperature changes, used in automated weather stations to record temperature every second
• Minimum temperature thermometer


  Alcohol-in-glass thermometer containing a moveable index that indicates the lowest temperature reached since the last reset
• Automatic Weather Station (AWS)


  • Can operate independently with its own solar power supply and integrated communication
  • Sends measurement data automatically to any platform
• Radiosonde

  A battery-powered telemetry instrument carried into the atmosphere by a weather balloon that measures various atmospheric parameters and transmits them by radio to a ground receiver
• Radiosonde measurements


  • Altitude, pressure, temperature, relative humidity, wind speed and direction
• Soil temperature sensors


  • Come in a variety of designs using thermistors, thermocouples, thermocouple wires, and averaging thermocouples
  • The electrical signals transmitted from the sensors to data loggers can be converted to different units of measurement, including °C, °F, and °K
  • Widely used in the measurement and research of agriculture, forestry, geology, farmland, water conservancy, forest, lawn, highway, railway maintenance
• Pyrheliometers


  Instruments used to measure direct solar radiation, with the receiving surfaces arranged to be normal to the solar direction
• Sunshine recorder


  Instrument that uses a glass ball to concentrate sunlight into a ray that burns a mark onto a card, indicating the duration of sunshine
• Modern sunshine recorders use electronics and computers for precise data that do not depend on a human interpreter, and can also measure global and diffuse radiation