LANDSCAPE ECOLOGY SREM 3011 LECTURE 14 Dr Brendan Mackey Department of Geography The Australian National University
LANDSCAPE ECOLOGY SREM 3011 LECTURE 14 Dr Brendan Mackey Department of Geography The Australian National University
Radiation Modelling Amount of radiation critical for plants and animals: (1)Affects photosynthesis primary productivity (2)Thermal regime air and soil temperature (3) Controls evaporation rate soil moisture Evaporation liquid water water vapour requires energy round atmosphere Energy comes from solar radiation Hence, people record aspect as an index of how exposed/sheltered a site is, as shaded sites are cooler and moister
Radiation Modelling • Amount of radiation critical for plants and animals: (1) Affects photosynthesis primary productivity (2) Thermal regime air and soil temperature (3) Controls evaporation rate soil moisture - Evaporation liquid water water vapour requires energy ground atmosphere - Energy comes from solar radiation Hence, people record aspect as an index of how exposed/sheltered a site is, as shaded sites are cooler and moister
Components and parameters of the SRAD solar radiation Extraterrestrial model Incident Radiation Latitude Only those parameters Date(Solar relevant to incoming short-wave radiation Atmospheric are shown Transmittance(15) T Lapse Rate(14.3) Diffuse Radiation Sunshine fraction Topography (from DEM) NB SRAD calculates radiation Topographic Shading using a dem Albedo (3)
Components and parameters of the SRAD solar radiation model Only those parameters relevant to incoming short-wave radiation are shown NB SRAD calculates radiation using a DEM
But amount of radiation received at a location is a function of: (1)Aspect (2) Slope (3 Horizon shading (4)Time of year angle of sun in the sk (5)Latitude July Tropic Cance March Se 0 Equate Cairns opIC of 18 Jan Capricorn ie. In winter sun is to the north and · S-E Aust low in horizon · Tasmania
But, amount of radiation received at a location is a function of: (1) Aspect (2) Slope (3) Horizon shading (4) Time of year (5) Latitude angle of sun in the sky ie. In winter, sun is to the north and low in horizon • Tasmania • S-E Aust Tropic of Capricorn Equator Tropic of Cancer 0 -180 July Jan March Sept Cairns
Radiation is measured by Met. bureau using radiometers on flat ground Therefore, interpolation surface contains no samples of radiation on an inclined surface Alternative is to model radiation using a deter- ministic, process-simulation model-"cloudy - requires user to provide estimates of about 10 parameters to calibrate model to prevailing atmospheric and terrain conditions calculates radiation on an inclined surface
• Radiation is measured by Met. bureau using radiometers on flat ground Therefore, interpolation surface contains no samples of radiation on an inclined surface • Alternative is to model radiation using a deterministic, process-simulation model - “cloudy” requires user to provide estimates of about 10 parameters to calibrate model to prevailing atmospheric and terrain conditions calculates radiation on an inclined surface