Climate Variables
SILO climate data are available for the following primary and derived variables on a daily timestep over the period 1889–present.
| Climate data | Variable | Primary or derived |
Short name/code | Name in API requests |
|---|---|---|---|---|
| Rainfall (mm) | Daily rainfall | Primary | daily_rain | R |
| Monthly rainfall | Primary | monthly_rain | ||
| Temperature (℃) | Maximum temperature | Primary | max_temp | X |
| Minimum temperature | Primary | min_temp | N | |
| Vapour pressure (hPa) | Vapour pressure | Primary | vp | V |
| Vapour pressure deficit | Derived | vp_deficit | D | |
| Evaporation (mm) | Class A pan evaporation | Primary | evap_pan | E |
| Synthetic estimate1 | Derived | evap_syn | S | |
| Combination (synthetic estimate pre-1970, class A pan 1970 onwards) | Derived | evap_comb | C | |
| Morton's shallow lake evaporation | Derived | evap_morton_lake | L | |
| Solar radiation (MJ/m2) | Solar exposure, consisting of both direct and diffuse components | Derived | radiation | J |
| Relative humidity (%) | Relative humidity at the time of maximum temperature | Derived | rh_tmax | H |
| Relative humidity at the time of minimum temperature | Derived | rh_tmin | G | |
| Evapotranspiration (mm) | FAO564 short crop | Derived | et_short_crop | F |
| ASCE5 tall crop6 | Derived | et_tall_crop | T | |
| Morton's areal actual evapotranspiration | Derived | et_morton_actual | A | |
| Morton's point potential evapotranspiration | Derived | et_morton_potential | P | |
| Morton's wet-environment areal potential evapotranspiration over land | Derived | et_morton_wet | W | |
| Mean sea level pressure (hPa) | Mean sea level pressure | Derived | mslp | M |
Monthly rainfall has a monthly timestep.
In point datasets Class A pan evaporation data are shifted to the previous day (see the FAQ "Why are evaporation data shifted to the day before?").
Metadata describing the primary variables and the procedures used to construct them are available in the Queensland Spatial Catalogue.
Variable information
Solar radiation: total incoming downward shortwave radiation on a horizontal surface, derived from estimates of cloud oktas and sunshine duration3.
Relative humidity: calculated using the vapour pressure measured at 9am, and the saturation vapour pressure computed using either the maximum or minimum temperature6.
Evaporation and evapotranspiration: an overview of the variables provided by SILO is available here.
Publications referenced
- Rayner, D. (2005). Australian synthetic daily Class A pan evaporation. Technical Report December 2005, Queensland Department of Natural Resources and Mines, Indooroopilly, Qld., Australia, 40 pp.
- Morton, F. I. (1983). Operational estimates of areal evapotranspiration and their significance to the science and practice of hydrology, Journal of Hydrology, Volume 66, 1-76.
- Zajaczkowski, J., Wong, K., & Carter, J. (2013). Improved historical solar radiation gridded data for Australia, Environmental Modelling & Software, Volume 49, 64–77. DOI: 10.1016/j.envsoft.2013.06.013.
- Food and Agriculture Organization of the United Nations, Irrigation and drainage paper 56: Crop evapotranspiration - Guidelines for computing crop water requirements, 1998.
- ASCE’s Standardized Reference Evapotranspiration Equation, proceedings of the National Irrigation Symposium, Phoenix, Arizona, 2000.
- For further details refer to Jeffrey, S.J., Carter, J.O., Moodie, K.B. and Beswick, A.R. (2001). Using spatial interpolation to construct a comprehensive archive of Australian climate data, Environmental Modelling and Software, Volume 16/4, 309-330. DOI: 10.1016/S1364-8152(01)00008-1.
For a full list of publications relevant to SILO data, please see the Publications and references page.
