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Project Progress

Ent Dynamic Global Terrestrial Ecosystem Model (Ent DGTEM) (Kiang, collaborators at NASA GISS, NASA GSFC, CUNY Hunter College). Last year we tested global off-line simulations of Earth seasonal vegetation dynamics, forced with observed meteorology, showing reasonable predictions of leaf area. This year, we implemented a full carbon cycle in the Goddard Institute for Space Studies (GISS) GCM, in collaboration with Anastasia Romanou at GISS, who implemented the ocean biogeochemistry model of VPL Co-I Gregg into the ocean model of the GISS GCM. We are continuing evaluation and testing of the coupled carbon dynamics to achieve a balanced carbon cycle. In collaboration with Dr. Wenge Ni-Meister at the City University of New York, Hunter College, and her funding from the ICESat/GLAS program, the interim land cover dataset of the previous year is now being upgraded to utilize the latest MODIS products (land cover, leaf area index, albedo), as well as LiDAR of ICESat/GLAS (vegetation height) to serve as both boundary conditions or as a performance evaluation dataset. Two papers were published on the Ent model’s canopy radiative transfer scheme for mixed canopies and clumped foliage.

NASA Ocean Biogeochemical Model (NOBM) (Gregg, collaborators at NASA GISS, NASA GSFC). The NOBM is a model previously developed at NASA GSFC that is now being integrated within two modeling systems: the GISS Model E and GMAO GEOS-5 Earth system models. NOBM has been successfully integrated into GISS Model E and has been applied for post-industrial carbon cycling. A paper is being drafted to be submitted to Ocean Modelling. Efforts to integrate into GEOS-5 are continuing, and the model has been partially integrated under the protocols of the Earth System Modeling Framework.

Life most likely formed first underwater on the Early Earth, since water serves as a solvent as well as providing protection again UV radiation. The ocean biogeochemistry module will afford simulation of such phenomena as sulfur cycling and iron-utilizing anoxygenic photosynthesis on the Early Earth, the stratification of dominant photosynthetic pigments by light quality, and potential variations in the 50% of net primary productivity of life on the modern Earth. Using an earlier OGCM, NOBM was applied to questions relating to early life on Earth in an effort to understand possible scenarios on other planets. A global experiment was conducted using cyanobacteria as the only photosynthetic group in the oceans (i.e., modern diatoms, chlorophytes, and coccolithophores were removed from the standard NOBM configuration). They were consumed by primitive heterotrophic bacteria. There was no iron limitation assuming that volcanic sources of iron were abundant. Also the atmospheric carbon partial pressure was assumed to be 1000 uatm.

The analyses showed that the early Earth ocean had 19% less primary production and 35% more nitrate due to slower growth by the cyanobacteria, and reduced nutrient uptake efficiency relative to modern phytoplankton. Silica concentrations were of course much higher than the modern Earth since cyanobacteria do not uptake silica. Additionally there was 8% more total carbon in the oceans as a result of higher atmospheric pCO2.