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SUMMARY:Developing land surface and vegetation models... by a field workin
 g ecologist! - Dr Rachael Turton\, Department of Geography\, University of
  Cambridge
DTSTART:20171123T130000Z
DTEND:20171123T140000Z
UID:TALK87811@talks.cam.ac.uk
CONTACT:Amy McGuire
DESCRIPTION:I’m going to give a two part presentation\, firstly on my Ph
 D research on snow-vegetation interactions in JULES (Joint UK Land Environ
 ment Simulator)\, the UK land surface model.  Secondly\, I’ll introduce 
 my PDRA on representing plant growth processes in the HYBRID vegetation mo
 del\, using data from a novel chilling experiment at Harvard Forest.\n\nTh
 e radiative balance of sparse seasonally snow-covered forests are poorly r
 epresented within land surface models.  High latitudes sparse canopies app
 ear dense and impenetrable in early spring due to low solar elevation.  Sh
 ortwave radiation penetration is highly spatial and temporally variable\, 
 and long shadows are cast over the snow surface.  Yet incident shortwave r
 adiation acts to increase longwave radiation to the snow surface.  Field m
 easurements are used to parameterise a new shaded gap tile\, which improve
 s the land-surface snow interactions in the JULES model.\n\nCurrent global
  vegetation models drive plant growth with photosynthesis\, which is contr
 olled by light\, temperature\, water\, and CO2. In this way they are able 
 to reproduce the historical land carbon sink as a consequence of CO2 ferti
 lization. However\, experimental work suggests that the vegetation respons
 e to rising CO2 is strongly limited by the sink (growth) capacity of the t
 ree rather than the source (photosynthesis) under natural conditions. Stud
 ies have shown high concentrations of non-structural carbon (a product of 
 photosynthesis) observed in wood\, thus indicating photosynthesis is not l
 imiting tree growth\, at least in the short-term. Observations on mature p
 ine\, maple\, and oak trees at Harvard Forest will be used to incorporate 
 the processes controlling growth and wood development within a sink-limite
 d vegetation model\, which will examine the implications for the historica
 l and future global carbon balance.
LOCATION:Rm 101\, William Hardy Building\, Department of Geography\, Downi
 ng Site
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