EESB04H3 Lecture Notes - Lecture 7: Airwatt, Hygroscopy, Pressure Measurement
1 Dec 2016
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Lecture 7 soil moisture & intro to unsaturated flow. Et calculated by penman-monteith approach = sensitive to resistivity terms, which are actually very difficult to accurately parameterize. Oftentimes only directly useable in research situations. In practice, estimations often applied through reference crop evaporation approach. Everything in reference crop et = related back to et from. Idealized surface, consisting of grass crop with uniform height/specific physical features. (given ra and rs) multipled by crop coefficient (kc) for particular crop to arrive at pet. Kc changed with differenct growth stages of a crop. Ra calculated for reference crop as 209/u2, where u2 = wind speed at 2m height. Anything from where you can see water surface from where you are standing. Vast majority of storage below ground or in ice caps. 2 areas: soil water zone (unsaturated), groundwater zone (saturated) Precipitation, evapotranspiration, and change in storage (most important from water balance)
