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Evaluation Of Continental Carbon Cycle Simulations With North American Flux Tower Observations, Brett M. Raczka, Kenneth J. Davis, Deborah N. Huntzinger, Ronald P. Neilson, Benjamin Poulter, Andrew D. Richardson, Jingfeng Xiao, Ian Baker, Philippe Ciais, Trevor F. Keenan, Beverly Law, Wilfred M. Post, Daniel Ricciuto, Kevin Schaefer, Hanqin Tian, Enrico Tomelleri, Hans Verbeeck, Nicolas Viovy
Evaluation Of Continental Carbon Cycle Simulations With North American Flux Tower Observations, Brett M. Raczka, Kenneth J. Davis, Deborah N. Huntzinger, Ronald P. Neilson, Benjamin Poulter, Andrew D. Richardson, Jingfeng Xiao, Ian Baker, Philippe Ciais, Trevor F. Keenan, Beverly Law, Wilfred M. Post, Daniel Ricciuto, Kevin Schaefer, Hanqin Tian, Enrico Tomelleri, Hans Verbeeck, Nicolas Viovy
Earth Systems Research Center
Terrestrial biosphere models can help identify physical processes that control carbon dynamics, including land–atmosphere CO2 fluxes, and have great potential to predict the terrestrial ecosystem response to changing climate. The skill of models that provide continental-scale carbon flux estimates, however, remains largely untested. This paper evaluates the performance of continental-scale flux estimates from 17 models against observations from 36 North American flux towers. Fluxes extracted from regional model simulations were compared with co-located flux tower observations at monthly and annual time increments. Site-level model simulations were used to help interpret sources of the mismatch between the regional simulations and site-based …
Vegetation Response To Extreme Climate Events On The Mongolian Plateau From 2000 To 2010, Ranjeet John, Jiquan Chen, Zu-Tao Ou-Yang, Jingfeng Xiao, Richard Becker, Arindam Samanta, Sangram Ganguly, Wenping Yuan, Ochirbat Batkhishig
Vegetation Response To Extreme Climate Events On The Mongolian Plateau From 2000 To 2010, Ranjeet John, Jiquan Chen, Zu-Tao Ou-Yang, Jingfeng Xiao, Richard Becker, Arindam Samanta, Sangram Ganguly, Wenping Yuan, Ochirbat Batkhishig
Earth Systems Research Center
Climate change has led to more frequent extreme winters (aka, dzud) and summer droughts on the Mongolian Plateau during the last decade. Among these events, the 2000–2002 combined summer drought–dzud and 2010 dzud were the most severe on vegetation. We examined the vegetation response to these extremes through the past decade across the Mongolian Plateau as compared to decadal means. We first assessed the severity and extent of drought using the Tropical Rainfall Measuring Mission (TRMM) precipitation data and the Palmer drought severity index (PDSI). We then examined the effects of drought by mapping anomalies in vegetation indices (EVI, EVI2) …
The Size Range Of Bubbles That Produce Ash During Explosive Volcanic Eruptions, Kimberly Genareau, Gopal K. Mulukutla, Alexander A. Proussevitch, Adam J. Durant, William I. Rose, Dork L. Sahagian
The Size Range Of Bubbles That Produce Ash During Explosive Volcanic Eruptions, Kimberly Genareau, Gopal K. Mulukutla, Alexander A. Proussevitch, Adam J. Durant, William I. Rose, Dork L. Sahagian
Earth Systems Research Center
Volcanic eruptions can produce ash particles with a range of sizes and morphologies. Here we morphologically distinguish two textural types: Simple (generally smaller) ash particles, where the observable surface displays a single measureable bubble because there is at most one vesicle imprint preserved on each facet of the particle; and complex ash particles, which display multiple vesicle imprints on their surfaces for measurement and may contain complete, unfragmented vesicles in their interiors. Digital elevation models from stereo-scanning electron microscopic images of complex ash particles from the 14 October 1974 sub-Plinian eruption of Volcán Fuego, Guatemala and the 18 May 1980 …
The Use Of Forest Stand Age Information In An Atmospheric Co2 Inversion Applied To North America, Feng Deng, Jing M. Chen, Y. Pan, W. Peters, R. Birdsey, K. Mccullough, Jingfeng Xiao
The Use Of Forest Stand Age Information In An Atmospheric Co2 Inversion Applied To North America, Feng Deng, Jing M. Chen, Y. Pan, W. Peters, R. Birdsey, K. Mccullough, Jingfeng Xiao
Earth Systems Research Center
Atmospheric inversions have become an important tool in quantifying carbon dioxide (CO2) sinks and sources at a variety of spatiotemporal scales, but associated large uncertainties restrain the inversion research community from reaching agreement on many important subjects. We enhanced an atmospheric inversion of the CO2 flux for North America by introducing spatially explicit information on forest stand age for US and Canada as an additional constraint, since forest carbon dynamics are closely related to time since disturbance. To use stand age information in the inversion, we converted stand age into an age factor, and included the covariances between subcontinental regions …
Recovery From Disturbance Requires Resynchronization Of Ecosystem Nutrient Cycles, Edward B. Rastetter, Ruth D. Yanai, R Quinn Thomas, Matthew A. Vadeboncoeur, Timothy J. Fahey, Melany C. Fisk, Bonnie L. Kwiatkowski, Steven P. Hamburg
Recovery From Disturbance Requires Resynchronization Of Ecosystem Nutrient Cycles, Edward B. Rastetter, Ruth D. Yanai, R Quinn Thomas, Matthew A. Vadeboncoeur, Timothy J. Fahey, Melany C. Fisk, Bonnie L. Kwiatkowski, Steven P. Hamburg
Earth Systems Research Center
Nitrogen (N) and phosphorus (P) are tightly cycled in most terrestrial ecosystems, with plant uptake more than 10 times higher than the rate of supply from deposition and weathering. This near-total dependence on recycled nutrients and the stoichiometric constraints on resource use by plants and microbes mean that the two cycles have to be synchronized such that the ratio of N:P in plant uptake, litterfall, and net mineralization are nearly the same. Disturbance can disrupt this synchronization if there is a disproportionate loss of one nutrient relative to the other. We model the resynchronization of N and P cycles following …
Climate Change At The Ecosystem Scale: A 50-Year Record In New Hampshire, Steven P. Hamburg, Matthew A. Vadeboncoeur, Andrew D. Richardson, Amey S. Bailey
Climate Change At The Ecosystem Scale: A 50-Year Record In New Hampshire, Steven P. Hamburg, Matthew A. Vadeboncoeur, Andrew D. Richardson, Amey S. Bailey
Earth Systems Research Center
Observing the full range of climate change impacts at the local scale is difficult. Predicted rates of change are often small relative to interannual variability, and few locations have sufficiently comprehensive long-term records of environmental variables to enable researchers to observe the fine-scale patterns that may be important to understanding the influence of climate change on biological systems at the taxon, community, and ecosystem levels. We examined a 50-year meteorological and hydrological record from the Hubbard Brook Experimental Forest (HBEF) in New Hampshire, an intensively monitored Long-Term Ecological Research site. Of the examined climate metrics, trends in temperature were the …