Day Walk Leadership Program

Open to any walker with experience and or training in bushwalking.

Bushwalking Leadership Program

Open to any walker with experience and or training in overnight bushwalking.

Bushwalk Leader Stages of Accreditation

With 5 stages courses can provide skills and qualifications to potential leaders.

List of of weather definitions.

View the summary of key terms.

ALL | A B C D E F G H I L M N O P R S T W
Advection
The horizontal movement or transfer of heat by convection.
Airmass
A thick and extensive portion of the troposphere having uniform temperature and humidity characteristics derived from its source region.
Albedo
The reflectivity of a surface.
Aspect
The way in which a slope faces towards or away from the sun and only has a noticeable affect in mid-high latitudes.
Climate
The average state of the atmosphere
Condensation
Water vapour changes (condenses) to droplets of water creating condensation forms like clouds, fog and dew.
Condensation Level
The level In the atmosphere at which condensation takes place.
Condensation Process
For condensation to occur, the temperature in the atmosphere or on the land surface must be reduced. As the temperature decreases, the relative humidity in the air increases. If the relative humidity reaches 100%, condensation occurs as the air becomes saturated with moisture.
Conduction
A form of energy that can be transferred by passing of heat by contact.
Convection
The transfer of heat by air currents or movements.
Convectional Rainfall
When moist air passes over land surfaces that have been strongly heated, the air is forced to rise and the condensation process begins.
Convergence Rainfall
When two large air masses come together or converge, the air is forced to rise and the condensation process commences.
Dew Formation
Dew is formed m calm and settled conditions generally associated with anti-cyclonic weather. During the night, the temperature falls and the air is unable to hold as much water vapour. The cooling which causes dew is the result of radiation during the night. The air-cools from the ground upwards, and if dew point is reached, condensation will occur.
Dew Point
The temperature at which condensation takes place.
Diurnal Range
The daily range of temperature or other weather elements.
Effective Rainfall
The average number of months where the average precipitation is greater than evapo-transpiration.
El Nino
A name given to the occasional development of a warm ocean current along the coast of Peru as a temporary replacement of the cold Humboldt current which normally operates. El Nino is an extension of the Equatorial current and leads to an increase in surface water temperature of ten degrees and a decrease in plankton, which thrive in the colder current As a result of this reduction in their food supply the fish population is seriously depleted. It recurs every seven to fourteen years and results from a weakening of the SE Trades in the Pacific.
Enhanced Greenhouse
Increased gas (greenhouse) carbon dioxide, methane, and nitrous oxide, CFC.
Evaporation
Liquid water changes to invisible water vapour.
Evapotranspiration
Evaporation from all terrestrial bodies.
Fog
Fog occurs when a whole layer of air is cooled below its dew point and moisture is condensed around tiny particles of dust. Depending on the temperature, it may be in the form of droplets of water, or ice atmosphere. Fogs are usually the result of air cooling by atmosphere. Fogs are usually the result of air cooling by contact with a cold surface atmosphere. Fogs are usually the result of air cooling by contact with a cold surface.contact with a cold surface crystals, both of which are heavier than air, but they are kept suspended by the slightest movements of the atmosphere. Fogs are usually the result of air cooling by contact with a cold surface.
Frontal Rainfall
Rainfall that is associated with the passage of a front over a location.
Fronts
The boundary zones between two air masses.
Greenhouse Effect
This is a natural warming process of the earth where the earth’s atmosphere has always retained heat from the sun by a process similar to that which takes place in a greenhouse. This works by the glass trapping the incoming short wave solar energy and preventing it from re-entering back into space as it has changed to long wave radiation. The temperature rises as more heat enters the greenhouse than escapes. In the case of the atmosphere it is not glass but a blanket of carbon dioxide, water vapour and other greenhouse gases. such as methane, which refract and reflect the heat energy and so prevent its outflow. When the sun’s energy reaches the earth, some of it is reflected back to space and the rest is absorbed. The absorbed energy . warms the earth’s surface, which then emits heat energy back toward space as longwave radiation. This outgoing longwave radiation is partially trapped by greenhouse gases such as carbon dioxide, methane and water vapour, which then radiate the energy in all directions, warming the earth’s surface and atmosphere.
Humidity
Humidity refers to the amount of water vapour present within the atmosphere. The actual amount of water vapour per unit volume is called absolute humidity. Relative humidity is the amount of water vapour in a given volume of air.
Infiltration
Some water falling on the earth's surface soaks into the ground,. and joins the underground aquifers.
Insolation
The suns energy transmitted in the form of short wave radiation.
Isobars
Lines drawn on a weather map to show places of equal barometric pressure.
Isohyets
Lines drawn on a map to show places of equal average annual rainfall (millimeters)
Isotherms
Lines drawn on a map to show places of equal average temperature.
Latent Heat
Heat transfer which occurs during evaporation, condensation, freezing and melting.
Long Wave Radiation
Outgoing radiation from the earth's surface - sometimes referred to as terrestrial radiation.
Meridian Altitude
The angle the sun makes with the earth’s surface at midday. Albedo The reflectivity of a surface.
Net Radiation
This is the difference between the incoming and outgoing energy.
Ocean Currents
Are large continuous movements of seawater which circulate in the oceans and are caused by the rotation of the earth.
Orographic Rainfall
When moist air is forced to rise up over a mountain range in its path.
Precipitation
Water falling from the clouds as rain, hail, snow or sleet.
Radiation
Heat in wave form sent out by the sun or earth.
Rainfall
Evaporation and transpiration from a land or plant source. Water changes from a liquid to a gas through heating of the water surface. Heat is trapped within the vapour (latent heat). Vapour rises in the air. Temperature decreases, condensation begins to occur, relative humidity starts to increase (if the relative humidity reaches 100% condensation occurs as the . air becomes saturated with moisture). Condensation takes place in the atmosphere- at a level called condensation level. The temp at which condensation occurs is called the dew point Water droplets become to heavy to be suspended in the cloud–they hen fall out of the cloud as rain.
Runoff
The water, which does not soak into the ground or is used by plants, animals and people, runs off the surface into streams, river and lakes.
Short Wave Radiation
Incoming radiation from the sun.
Symboptic Chart
A weather map.
Temperature Inversion
This is a feature occuring in the early morning after a clear night, when terrestrial radiation is lost to space and the air near the ground has become cooler than the air above.
The Atmosphere
An envelope of air composed mainly of nitrogen and oxygen, which stretches from the earth's surface to about l00km above our planet.
The Biophysical Environment
The interaction of the atmosphere, hydrosphere, lithosphere and biosphere.
The Biosphere
The system of living things and non-living environment with which they interact.
The Greenhouse Effect
This is a natural warming process of the earth where the earth's atmosphere has always retained heat from the sun by a process similar to that which takes place in a greenhouse. This works by the glass trapping the incoming short wave solar energy and preventing it from re-entering back into space as it has changed to long wave radiation. The temperature rises as more heat enters the greenhouse than escapes. In the case of the atmosphere it is not glass but a blanket of carbon dioxide, water vapour and other greenhouse gases. such as methane, which refract and reflect the heat energy and so prevent its outflow. When the sun's energy reaches the earth, some of it is reflected back to space and the rest is absorbed. The absorbed energy . warms the earth's surface, which then emits heat energy back toward space as longwave radiation. This outgoing longwave radiation is partially trapped by greenhouse gases such as carbon dioxide, methane and water vapour, which then radiate the energy in all directions, warming the earth's surface and atmosphere.
The Hydrospher
The layer of water that cover the earth from a maximum depth of more then 11km in the oceans to shallower and less extensive bodies of water in lakes and river.
The Lithosphere
The sphere of rocks or upper layer of the mantle, which lies above the hot, semi molten and deformed rock of the deeper earth's mantle.
The Radiation Balance
This is a comparison of the energy gained and lo t (inputs and outputs of energy).
The Stratosphere
The layer from about 12,000 meters to about 50kms above the surface–this is where the sky is always clear, there is no water vapour and no changes in the weather.
The Thermal Equator
A belt of heat about ten degrees either side of the equator.
The Troposphere
The lowest layer nearest the surface i.e. where all our weather patterns develop (12,000m above the surface).
The Water Cycle
The movement of water from the sea to clouds: to rain or snow: to rivers or underground and back to the sea.
Weather
The day to day description and measurement of the weather elements (temperature, moisture, cloud and wind)
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