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4. INTERCEPTION. Evapo - Transpiration ET. Precipitation P. S. Throughfall P T. Stemflow P S. Dripping P D. INPUT = OUTPUT +/- STORAGE. P = (P T + P S + P D + E) +/- S. P forest = (P T + P S + P D ). P interception = E +/- S. P = P forest + P interception.
E N D
Evapo- Transpiration ET Precipitation P S Throughfall PT Stemflow PS Dripping PD
INPUT = OUTPUT +/- STORAGE P = (PT + PS + PD + E) +/- S Pforest = (PT + PS + PD) Pinterception = E +/- S P = Pforest + Pinterception
ATMOSPHERE VEGETATION GROUND
ATMOSPHERE VEGETATION GROUND
ATMOSPHERE VEGETATION GROUND
ATMOSPHERE VEGETATION GROUND
ATMOSPHERE VEGETATION GROUND
ATMOSPHERE VEGETATION GROUND
Include Evaporative Loss
Without ET
Without ET
Observed interception Calculated as the mean of the “interceptometer’ readings Source: R. Horton, 1919. Monthly Weather Review
Initially leaf storage accounts for all precipitation in the storm Transition during which leaf storage becomes proportionally less important relative to the total precipitation in the storm. Evaporation as a fixed percentage of precipitation accounts for most of the precipitation NOT reaching the ground
Initially leaf storage accounts for all precipitation in the storm Transition during which leaf storage becomes proportionally less important relative to the total precipitation in the storm. Evaporation as a fixed percentage of precipitation accounts for most of the precipitation NOT reaching the ground Snowmelt drip After Schomaker, 1966
Front Ranges, Colorado 2012 Forest Fires 2013 Floods Source: Bonan, 2008: Ecological Climatology
INTERRELATIONSHIP BETWEEN INTERCEPTION TERMS L = S + K.E.t S = Leaf storage (e.g. 0.05cm) K = Leaf Area Index (e.g. 0.6) E = Evaporation rate (e.g. 0.1 cm/hr) Rainfall intensity = 0.5 cm/hr Cumulative Rainfall Cumulative Interception (L)
Veg Ground
Leaf area index in monocultures and mixtures of Cedrela, Cordia, and Hyeronima from age 1.0 to 3.5 yr at La Selva Biological Station, CostaRica. From: Menalled, Kelty and Ewell, 1998
INTERRELATIONSHIP BETWEEN INTERCEPTION TERMS Interception as % of rainfall
(inches) Source: Gray, 1970, Principles of Hydrology
Source: Gray, 1970, Principles of Hydrology