Skip to main content
ARS Home » Research » Publications at this Location » Publication #138604
Title: SENSITIVITY OF REGIONAL CROP YIELD SIMULATIONS TO ROUGHTNESS EFFECTS IN FRAGMENTED LANDSCAPES

Author
item WENG, R - POTSDAM-INST, GERMANY
item WECHSUNG, F - POTSDAM-INST, GERMAN
item KRYSANOVA, V - POTSDAM-INST, GERMANY
item Kimball, Bruce

Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 10/15/2001
Publication Date: 10/21/2001
Citation: Weng, R., Wechsung, F., Krysanova, V., Kimball, B.A. 2001. Sensitivity of regional crop yield simulations to roughtness effects in fragmented landscapes. Agronomy Abstracts.

Interpretive Summary:

Technical Abstract: Landscape variations add drag to the atmosphere because of sudden changes in vegetation height at the edges of a vegetation patch, i.e. they could even increase the roughness of the landscape above the largest surface roughness for single patches within a region. Subsequently turbulent kinetic energy of the air above the rough surface increases and therefore the total resistance for vapour transport - partly defined via roughness (height) - decreases. Neglecting this effect in regional studies leads to underestimates of evapotranspiration and stomatal control, especially in plant growth and crop yield simulations where usually the consideration is limited to the roughness height within single crop patches. Using a roughness length aggregation concept, which takes into account the ambient landscape patches, "regional evapotranspiration" was derived for a more compatible assessment of local evapotranspiration in regional crop yield simulations. Within this concept the regional roughness depends on factors like patch composition, exposure to wind, horizontal area, horizontal shape, number and silhouette of the subsumed patches. Simulation studies carried out demonstrate the effect of such a correction on the plant water status under current and increased CO2 for fragmented landscapes.