Climate-Modelling

[Music plays and text appears with CSIRO logo:  Climate Modelling]

Narrator:  We know how and why weather occurs.

[Image changes to show an animation of different weather events]

It varies over minutes, hours and days.  Climate is the average weather.  We understand the physics and chemistry that describe the interactions between the atmosphere, the oceans, the land surface, and the biosphere that create weather and climate.

[Text appears on animation:  Atmosphere; Oceans; Land surface; Biosphere]

Scientists use this knowledge to program computer models that simulate our weather and climate.

[Image changes to show a computerised image of a spinning globe and text appears:  Globate Climate Model]

These are called global climate models, and they provide forecasts of weather over the next one to seven days, and assessments of causes of past climate variability and projections of future climate change.

[Text appears on screen:  Access]

There are over 40 global climate models internationally, one of which is Australia’s ACCESS model.

[Text appears on screen:  Australian Community Climate and Earth-System Simulator]

[Image changes to show an animation of a clock’s hands moving and text appears:  Weather]

ACCESS provides weather forecasts for Australia.

[Image changes to show a computerised image of a diary and predicted weather forecast]

Looking a week ahead the model enables meteorologists to forecast rainfall and temperatures.

[Image changes to show a computerised image of a diary]

[Image changes to show a graph and text appears:  Climate]

Looking decades ahead the model enables climate scientists to estimate ranges of temperature and rainfall.

[Text appears on the graph:  Present; Future]

The model works by dividing the earth into boxes.  Typically the boxes measure about 200 kilometres by 200 kilometres.

[Image changes to show a computerised image of boxes stacked on top of each other and text appears:  200KM x 200KM]

To project future climate we start with the measured or estimated conditions at every corner.

[Image changes to show a computerised image and various temperatures and kilometres are displayed]

The model steps forward in time, creating new conditions at each corner.

[Image changes to show an animation]

The output from each step becomes the input for the next, allowing us to run the model as far into the future as required.  Over regions with complex mountains or coastlines better climate simulations require dynamic downscaling.

[Image changes to show an animation]

Downscaling models have boxes that typically measure 50 kilometres by 50 kilometres or less.

[Text appears on animation:  50KM x 50KM]

[Image changes to show computerised simulations of a globe and text appears:  Computer Model; Satellite Image]

Models can reliably simulate the climate that we have experienced in past decades and future decades based on different assumptions about how greenhouse gases will increase.

[Image changes to show an animation]

Climate models help us understand past climate variability, manage weather fluctuations over the coming days, and plan for long term climate change.

[CSIRO logo appears with text:  Climate Modelling]

[Australian Government logo appears with text:  An Australian Government Initiative | Inspiring Australia.  Model simulations supplied by the Centre for Australian Weather & Climate Research, a partnership between CSIRO and the Bureau of Meteorology.  Thanks to Dr Lawrie Rikus.]