Talk at CES on 9 December 2016 at 10:30 am titled "Role of Terrestrial Ecosystems in Climate Change: Tandem use of Observations, Modeling and Remote Sensing to Understand their Complexity" by Dr. Ajit Govind from Kerala University
The terrestrial biogeochemical processes are perhaps the most dynamic and complex
component of the Earth’s Climate system. In order to better understand this complex system, the
integrated use of process-based modeling, remote sensing (RS) and measurements at multiple scales
(with an ecohydrological spirit) is proposed.
At the outset, a process-based ecohydrological model (BEPS-TerrainLab V2.0) that has tight
coupling of water (W), energy (E), carbon (C) and nitrogen (N) cycles is discussed as applied to a
forested ecosystem in boreal Canada. The potential errors in the simulated C fluxes under abstracted
hydrology are presented using a numerical experiment. Further, an improved and generic model
(STEPS) is presented as applied to a patchy-landscape in southern France. Improvements made
towards the modeling of canopy radiative transfer mechanism, in addition to some issues that are
pertinent to agro-ecosystems (C4 photosynthesis, irrigation, fertilizer N etc.) are presented. In the
second part of the presentation, long-term modeling of C in the soil and vegetation is discussed from
the lessons learnt from various projects in the Canadian C Program and the AmeriFlux programs.
Some studies on the long term ecohydrological responses under climate change in the lower
Himalayas are also discussed.
Finally, large-scale ecohydrological interactions are discussed. An analysis of the recent trends
in the global vegetation is explored using long-term RS data (AVHRR). Because of the importance of
soil water in governing the global vegetation, I hypothesize a major limitation in the widely used
global estimate of terrestrial photosynthesis (MOD17A2). A modeling strategy that is being developed
to improve the MOD17A2 by incorporating soil moisture data is briefly explained. In this regard, I
also present an analysis of some global soil moisture products obtained from microwave RS (SMOSL3
and AMSRE-LPRM) with respect to a reanalysis product (ECMWF).