Climate information for Solar Energy

Further information

The Bureau of Meteorology undertakes direct solar measurements at a number of ground stations, as well as operating a computer model to estimate global and direct normal irradiance from satellite imagery. This section provides answers to frequently asked questions regarding these data, as well as providing information on additional data types and alternative sources of information.

Where to seek information

Most Australian States and Territories have a Government department which has responsibility for solar energy related issues. Names of these Departments are not consistent across Australia, and may change over time, but often includes Sustainability, Environment or Energy in the Department title.

The majority of solar energy conferences have a section devoted to solar resource assessment. Papers generally include topics on regional data analyses, new tools and techniques. The International Solar Energy Society's Solar World Congress is one such event. Within Australia, several previous conferences organised by the Australian Solar Energy Society included discussion about the Australian solar resource.

The Bureau's Data Services web page provides information to assist with obtaining a wide range of climate data and past weather information. It covers station data, maps and gridded data, and metadata, as well as various analysed data, and includes content available on this website as well as those data available on request to the Bureau.

Data FAQs

Are PAR data available from the Bureau of Meteorology?

Photosynthetically Active Radiation (PAR) is the portion of the solar spectrum - from approximately 400 to 700 nanometres - which is utilised in the process of photosynthesis. This spectral band is a subset of the spectral band measured by the Bureau's pyranometers, and can be determined from observations using special instruments. Alternatively, when expressed as an energy, PAR may be estimated using an empirical relationship such as: PAR=0.45 * Global solar exposure (MJm-2). For further information refer to, for example:

Does the Bureau provide illuminance data?

Illuminance is the total luminous flux incident on a surface per unit area, where the luminous flux is the power of light weighted to correspond to the sensitivity of the human eye. The Bureau of Meteorology does not have illuminance data.

Can the Bureau provide Leaf Area Index data?

The Bureau of Meteorology does not provide Leaf Area Index data. These data, along with the Fraction of Absorbed Photosynthetically Active Radiation (FAPAR) can be obtained in a research-oriented spatial data format from the National Computational Infrastructure website.

Are Clearness Index data available from the Bureau?
The Clearness Index is a measure of the reduction in solar energy as sunlight passes through the atmosphere. It is equal to the ratio of global solar radiation on the surface of the earth to the extraterrestrial radiation at the top of the atmosphere, and can range from approximately 0.8 in the clearest conditions to near zero in overcast conditions. The Bureau does not provide measurements of Clearness Index.
Are UV data available from the Bureau?

The Bureau of Meteorology has a UV forecast service, but it does not provide observations of UV radiation. UV data from a number of locations are available from the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA).

Does the Bureau provide access to solar observations from other groups?

Not at this time. The solar data available from the Bureau of Meteorology are from its own ground observation network and from the Bureau's model which processes satellite images.

Can I obtain solar information from areas within the ocean or other large areas of water?

The Bureau's model to estimate solar exposure from satellite images currently does not process imagery over large bodies of water. However, during the processing of the imagery over land, the solar exposure is extrapolated approximately 50km from the coastline to include narrow peninsulas and small islands close to the mainland.

What causes the small regions of lower exposure I sometimes see on the solar exposure maps?

Large salt lakes can sometimes appear to have a lower solar exposure than the surrounding land. The computer model processes the whitish salt areas as if they were cloud, which would block some of the sunlight reaching the ground.

How frequently are the Bureau's solar data updated?

Daily solar data for locations via Climate Data Online, and daily gridded solar data and maps are nominally updated shortly after midnight each day.

Hourly solar grids and one minute solar data are updated at various times during the year. Please visit (or subscribe to) our Updates to One Minute Solar Data and Changes to Solar Data pages to keep informed of updates.

Solar observation FAQs

How accurate are the solar data?
The Bureau generally uses a measure of uncertainty to describe the confidence we have in the data. Data quality assurance and quality control of the station measurements are such that the target of 95% uncertainties for any minute exposure quantity of 3% or 900 Jm-2 (which ever is the greater) have been achieved and improved upon. Studies indicate that, for monthly satellite-derived global exposures, data have an uncertainty of approximately 7%. The uncertainty will increase as we go to finer - daily and hourly - temporal resolution data.
How do I know what equipment has been used to make observations?
The Bureau's Climate Data Online product provides access to station metadata, which include a summary of the equipment installed at a site. The station metadata file for Alice Springs provides an example of the types of information available.
What is the spectral range of satellite-derived solar data?
The spectral range of the satellite imaging equipment providing the raw data used in creating the Bureau's solar maps is narrower than that of a ground-based pyranometer, and differs between types of satellite. However, the Bureau's computer model compensates for this limitation when calculating the solar irradiance.

Solar Theory FAQs

Are atmospheric aerosols important for solar energy in Australia?

Many atmospheric aerosols are a natural component of our atmosphere. They include wind-borne dust, salt particles originating from the evaporation of sea spray, and the fine drops of volatile oil emitted by eucalypt forests. Anthropogenic aerosols (caused by humans) include a high portion of the sulphates in the air.

A high atmospheric aerosol content can have an adverse effect on solar power generation. This occurs through absorption and reflection of incoming solar energy and, particularly, the scattering of light which reduces efficiency of concentrating solar power systems. While short-term increases can occur from fires and other phenomena, the atmosphere over Australia is relatively clean compared to some other parts of the world (Europe, for example) which have a significantly greater content of anthropogenic aerosols.

Solar Applications FAQs

How do I calculate energy from a solar panel?

The simplest way to obtain an estimate of the energy output from a solar panel array is to search the internet for online guides, in the form of maps, tables or graphs. One such example is the Consumer Guide produced by the Clean Energy Council.

To derive a more accurate estimate of the energy yield it is necessary to have information about a number of parameters, including the following:

  • Amount of direct beam and diffuse solar exposure at the location, preferably for at least hourly intervals;
  • Tilt and azimuth (direction from north) angles of the panels;
  • Latitude of the location where the panels are installed;
  • Time of year if monthly information is required;
  • Potential shading by nearby obstructions;
  • Efficiency of the solar panels in converting energy from the sun to electrical energy.

The energy will differ from year to year due to variability in the amount of solar energy available; for example, with changes in cloudiness from El Niño to La Niña years.

Other FAQs

Does the Bureau provide solar forecasts?
Solar irradiance forecasts are an integral component of a numerical weather prediction (NWP) model, and the Bureau continues research and development in this area. There is currently no explicit freely available solar forecast available to the public. However, NWP model solar forecasts are available from the Bureau's Registered User Service.

International resources