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
Short name/code
Rainfall (mm) Daily rainfall Primary daily_rain
Monthly rainfall Primary monthly_rain
Temperature (℃) Maximum temperature Primary max_temp
Minimum temperature Primary min_temp
Vapour pressure (hPa) Vapour pressure Primary vp
Vapour pressure deficit Derived vp_deficit
Evaporation (mm) Class A pan evaporation Primary evap_pan
Synthetic estimate1 Derived evap_syn
Combination (synthetic estimate pre-1970, class A pan 1970 onwards) Derived evap_comb
Morton's shallow lake evaporation Derived evap_morton_lake
Solar radiation (MJ/m2) Solar exposure, consisting of both direct and diffuse components Derived radiation
Relative humidity (%) Relative humidity at the time of maximum temperature Derived rh_tmax
Relative humidity at the time of minimum temperature Derived rh_tmin
Evapotranspiration (mm) FAO564 short crop Derived et_short_crop
ASCE5 tall crop6 Derived et_tall_crop
Morton's areal actual evapotranspiration Derived et_morton_actual
Morton's potential evapotranspiration Derived et_morton_potential
Morton's wet-environment areal evapotranspiration over land Derived et_morton_wet
Mean sea level pressure (hPa) Mean sea level pressure Derived mslp

Monthly rainfall has a monthly timestep.

Gridded datasets are not available for "Combination evaporation" (evap_comb). An archive can be created by combining synthetic evaporation (evap_syn) grids for all years up to 1970, and Class A pan evaporation (evap_pan) grids for 1970 and onwards.

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 duration2.

Relative humidity: calculated using the vapour pressure measured at 9am, and the saturation vapour pressure computed using either the maximum or minimum temperature 3.

Publications referenced

1. 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. Available online here.

2. 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.

3. 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.

4. Food and Agriculture Organization of the United Nations, Irrigation and drainage paper 56: Crop evapotranspiration - Guidelines for computing crop water requirements, 1998.

5. ASCE’s Standardized Reference Evapotranspiration Equation , proceedings of the National Irrigation Symposium, Phoenix, Arizona, 2000.

6. 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.

For a full list of publications relevant to SILO data, please see the Publications and references page.