EARTH SYSTEM PHYSICS - GUEST SEMINAR - MONDAY 20 APRIL

[Earth System Physics Section]

EARTH SYSTEM PHYSICS SEMINAR
Monday, 20 April - 14:30 hrs
Stasi Lecture Room, Leonardo da Vinci bldg., 1st floor

Guest speaker
Renato Braghiere
University of Reading, UK

IMPROVING LAND SURFACE MODEL TREATMENT OF VEGETATION CANOPY ARCHITECTURE

Land surface models (LSMs) are an important tool for understanding
land-surface-atmosphere dynamics and interactions and climate-carbon
feedbacks. Perhaps the partitioning of solar radiation between various
compartments of the surface constitutes the most important step to further
quantify the role of vegetation in redistributing energy and drive related
biogeophysical processes, as photosynthesis, evapotranspiration, changes
in leaf and soil temperature and snowmelt. The advent of the Two-Stream
(TS) solution brought more accuracy to LSMs as the radiation treatment was
divided into two directions (upward and downward) and properties (direct
and diffuse). It is known that diffuse solar radiation can enhance
photosynthetic capacity, as it penetrates more efficiently into the
vegetation canopy. Firstly, a statistical evaluation of the diffuse light
effect on energy and carbon fluxes over Amazon is conducted.  However,
even the broadly used TS scheme is not realistic enough to account for
effects on radiation propagation related to canopy architecture. The
vegetation structure varies considerably for different ecosystems and it
has an important impact on the amount of absorbed radiation and surface
albedo, which directly affects the surface energy and carbon balances. 3D
radiation transfer (RT) models are accurate tools to obtain energy
propagation and they have been widely used by the satellite community in
order to derive land surface characteristics, but because of their
complexity and computational costs, they are unsuitable for large areas
and long period runs. Secondly, to bring the reality of 3D RT models into
an efficient operational physically-based LSM, a parameterization
accounting for vegetation structure is introduced and tested.
Everyone is most welcome to attend.

-- 
Secretariat
Earth System Physics Section
the Abdus Salam International
Centre for Theoretical Physics
Strada Costiera 11
34151 Trieste, Italy
T. +39 040 2240374