The Terrestrial Biosphere Model Farm.

Model Intercomparison Projects (MIPs) are fundamental to our understanding of how the land surface responds to changes in climate. However, MIPs are challenging to conduct, requiring the organization of multiple, decentralized modeling teams throughout the world running common protocols. We explored centralizing these models on a single supercomputing system.

Author Correction: Modeling suggests fossil fuel emissions have been driving increased land carbon uptake since the turn of the 20th Century.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Carbon and Water Use Efficiencies: A Comparative Analysis of Ten Terrestrial Ecosystem Models under Changing Climate.

Terrestrial ecosystems carbon and water cycles are tightly coupled through photosynthesis and evapotranspiration processes. The ratios of carbon stored to carbon uptake and water loss to carbon gain are key ecophysiological indicators essential to assess the magnitude and response of the terrestrial plant to the changing climate. Here, we use estimates from 10 terrestrial ecosystem models to quantify the impacts of climate, atmospheric CO concentration, and nitrogen (N) deposition on water use efficiency (WUE), and carbon use efficiency (CUE).

Global vegetation biomass production efficiency constrained by models and observations.

Plants use only a fraction of their photosynthetically derived carbon for biomass production (BP). The biomass production efficiency (BPE), defined as the ratio of BP to photosynthesis, and its variation across and within vegetation types is poorly understood, which hinders our capacity to accurately estimate carbon turnover times and carbon sinks. Here, we present a new global estimation of BPE obtained by combining field measurements from 113 sites with 14 carbon cycle models.

Land carbon models underestimate the severity and duration of drought's impact on plant productivity.

The ability to accurately predict ecosystem drought response and recovery is necessary to produce reliable forecasts of land carbon uptake and future climate. Using a suite of models from the Multi-scale Synthesis and Terrestrial Model Intercomparison Project (MsTMIP), we assessed modeled net primary productivity (NPP) response to, and recovery from, drought events against a benchmark derived from tree ring observations between 1948 and 2008 across forested regions of the US and Europe. We find short lag times (0-6 months) between climate anomalies and modeled NPP response.

Enhanced peak growth of global vegetation and its key mechanisms.

The annual peak growth of vegetation is critical in characterizing the capacity of terrestrial ecosystem productivity and shaping the seasonality of atmospheric CO concentrations. The recent greening of global lands suggests an increasing trend of terrestrial vegetation growth, but whether or not the peak growth has been globally enhanced still remains unclear. Here, we use two global datasets of gross primary productivity (GPP) and a satellite-derived Normalized Difference Vegetation Index (NDVI) to characterize recent changes in annual peak vegetation growth (that is, GPP and NDVI).

Accelerating rates of Arctic carbon cycling revealed by long-term atmospheric CO measurements.

The contemporary Arctic carbon balance is uncertain, and the potential for a permafrost carbon feedback of anywhere from 50 to 200 petagrams of carbon (Schuur ., 2015) compromises accurate 21st-century global climate system projections. The 42-year record of atmospheric CO measurements at Barrow, Alaska (71.

Global patterns of drought recovery.

Drought, a recurring phenomenon with major impacts on both human and natural systems, is the most widespread climatic extreme that negatively affects the land carbon sink. Although twentieth-century trends in drought regimes are ambiguous, across many regions more frequent and severe droughts are expected in the twenty-first century. Recovery time-how long an ecosystem requires to revert to its pre-drought functional state-is a critical metric of drought impact.

Visual Reconciliation of Alternative Similarity Spaces in Climate Modeling.

Visual data analysis often requires grouping of data objects based on their similarity. In many application domains researchers use algorithms and techniques like clustering and multidimensional scaling to extract groupings from data. While extracting these groups using a single similarity criteria is relatively straightforward, comparing alternative criteria poses additional challenges.

Global patterns and controls of soil organic carbon dynamics as simulated by multiple terrestrial biosphere models: Current status and future directions.

Soil is the largest organic carbon (C) pool of terrestrial ecosystems, and C loss from soil accounts for a large proportion of land-atmosphere C exchange. Therefore, a small change in soil organic C (SOC) can affect atmospheric carbon dioxide (CO) concentration and climate change. In the past decades, a wide variety of studies have been conducted to quantify global SOC stocks and soil C exchange with the atmosphere through site measurements, inventories, and empirical/process-based modeling.

North American terrestrial CO uptake largely offset by CH and NO emissions: toward a full accounting of the greenhouse gas budget.

The terrestrial ecosystems of North America have been identified as a sink of atmospheric CO though there is no consensus on the magnitude. However, the emissions of non-CO greenhouse gases (CH and NO) may offset or even overturn the climate cooling effect induced by the CO sink. Using a coupled biogeochemical model, in this study, we have estimated the combined global warming potentials (GWP) of CO, CH and NO fluxes in North American terrestrial ecosystems and quantified the relative contributions of environmental factors to the GWP changes during 1979-2010.

New Conceptual Model for Soil Treatment Units: Formation of Multiple Hydraulic Zones during Unsaturated Wastewater Infiltration.

Onsite wastewater treatment systems are commonly used in the United States to reclaim domestic wastewater. A distinct biomat forms at the infiltrative surface, causing resistance to flow and decreasing soil moisture below the biomat. To simulate these conditions, previous modeling studies have used a two-layer approach: a thin biomat layer (1-5 cm thick) and the native soil layer below the biomat.

Carbon dioxide sequestration in cement kiln dust through mineral carbonation.

Carbon sequestration through the formation of carbonates is a potential means to reduce CO2 emissions. Alkaline industrial solid wastes typically have high mass fractions of reactive oxides that may not require preprocessing, making them an attractive source material for mineral carbonation The degree of mineral carbonation achievable in cement kiln dust (CKD) underambienttemperatures and pressures was examined through a series of batch and column experiments. The overall extent and potential mechanisms and rate behavior of the carbonation process were assessed through a complementary set of analytical and empirical methods, including mass change, thermal analysis, and X-ray diffraction.

Mineral carbonation for carbon sequestration in cement kiln dust from waste piles.

Alkaline earth metals, such as calcium and magnesium oxides, readily react with carbon dioxide (CO(2)) to produce stable carbonate minerals. Carbon sequestration through the formation of carbonate minerals is a potential means to reduce CO(2) emissions. Calcium-rich, industrial solid wastes and residues provide a potential source of highly reactive oxides, without the need for pre-processing.