PIK Biennial Report 2000-2001 - Potsdam Institute for Climate ...

Goal
To study the role of the land biosphere as a provider of
the human environment and services and as part of the
coupled physical and biogeochemical Earth system, on
the time-scale of historic and future human intervention,
i.e. years to a few centuries.
Research Questions
In this project, we address the following questions:
(a) What is the current and future structure and function
of the land biosphere as a provider of the human environment
and services?
(b) What is the current and future role of the land biosphere
as part of the coupled Earth system on the
(“human”) time-scale of years to a few centuries?
Fig. 3: Interannual Terrestrial carbon exchange anomalies (from
the 1980-98 mean) using the bottom-up LPJ-DGVM approach
(red), compared against top-down atmospheric inversion. Mean
inversion is in black (Bousquet, Peylin, LSCE), the range of 20
inversions (grey).
Tools and development
The Lund-Potsdam-Jena Dynamic Global Vegetation
Model (LPJ-DGVM) is one of the world’s leading models
of the global biospheric carbon cycle and of vegetation
dynamics. Continued development of key components
of the model, their validation with observed
ecosystem data on several scales, and the study of the
EVITA
Exergy, Vegetation and Information: Thermodynamics Approach
Project speaker: Yuri Svireshev
PIK project members: W. Steinborn
External project collaborators: Kiel Ecology Centre
past and future of the global carbon cycle are the current
focus of PIK’s work using LPJ. E.g. inclusion of permafrost,
a key influence on ecology in the boreal regions,
into LPJ-DGVM led to a considerable increase in model
performance. LPJ-DGVM representation of the hydrological
cycle has been improved and successfully validated
against seasonal, local- to global-scale data.
First Results
RECENT TERRESTRIAL CO 2 EXCHANGE
LPJ-DGVM seasonal carbon exchange has been compared
over regions with those derived from atmospheric
inversions. The importance of such work is first to locate
the main source-sink regions, important for environmental
policy (e.g. Kyoto debate), and second to identify,
understand and model the underlying processes sensitive
to current climatic variability, giving an insight into possible
future environmental changes.
GREENING OF THE NORTHERN LATITUDES
Using time series of climate data, the LPJ-DGVM models
an advance of spring in the last two decades and an
increase of vegetation abundance in the global boreal
zone. This is in excellent agreement with the observed
trends found independently in satellite data. The model
also reproduces the impact of atmospheric aerosols from
the Mount Pinatubo volcanic eruption in 1991 on vegetation
productivity and phenology in northern latitudes.
MODELLING OF REGIONAL FIRE PATTERNS
LPJ-DGVM simulates fire disturbance taking into
account multiple natural and anthropogenic causes and
processes such as fire spread. A regional version of this
fire model adapted to the Iberian Peninsula, successfully
reproduces both the number of fires occurring and the
area burnt, factors that co-determine local ecosystems.
This project is partly funded by BMBF, DFG, and the EU.
Goal
EVITA is a sub-project of BIS. EVITA aims to describe
the state of vegetation by applying the concept of thermodynamics,
in particular so-called exergy, to the
observed spectra of the radiation balance.
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