The role of non-structural carbohydrates in simulations of ecosystem carbon fluxes.

2020 ◽  
Author(s):  
Simon Jones ◽  
Lucy Rowland ◽  
Peter Cox ◽  
Debbie Hemming ◽  
Andy Wiltshire ◽  
...  
Keyword(s):  
Carbon Storage ◽  
Land Surface ◽  
Large Scale ◽  
Carbon Fluxes ◽  
Carbon Accumulation ◽  
Future Research ◽  
Labile Carbon ◽  
Ecosystem Carbon ◽  
Unrealistic Assumption ◽  
Plant Respiration

<p>Accurately representing the response of ecosystems to environmental change in land surface models (LSM) is crucial to making accurate predictions of future climate. Many LSMs do not correctly capture plant respiration and growth fluxes, particularly in response to extreme climatic events. This is in part due to the unrealistic assumption that total plant carbon expenditure (PCE) is always equal to gross carbon accumulation by photosynthesis. We present and evaluate a simple model of labile carbon storage and utilisation (SUGAR), designed to be integrated into an LSM, that allows simulated plant respiration and growth to vary independently of photosynthesis. SUGAR buffers simulated PCE against seasonal variation in photosynthesis, producing more constant (less variable) predictions of plant growth and respiration relative to an LSM that does not represent labile carbon storage. This allows the model to more accurately capture observed carbon fluxes at a large-scale drought experiment in a tropical moist forest in the Amazon, relative to the Joint UK Land Environment Simulator LSM (JULES). SUGAR is designed to improve the representation of carbon storage in LSMs and provides a simple framework that allows new processes to be integrated as the empirical understanding of carbon storage in plants improves. The study highlights the need for future research into carbon storage and allocation in plants, particularly in response to extreme climate events such as drought.</p>

scholarly journals The impact of a simple representation of non-structural carbohydrates on the simulated response of tropical forests to drought

2020 ◽  
Vol 17 (13) ◽  
pp. 3589-3612 ◽  
Author(s):  
Simon Jones ◽  
Lucy Rowland ◽  
Peter Cox ◽  
Deborah Hemming ◽  
Andy Wiltshire ◽  
...  
Keyword(s):  
Carbon Storage ◽  
Land Surface ◽  
Large Scale ◽  
Carbon Accumulation ◽  
Future Research ◽  
Labile Carbon ◽  
Moist Forest ◽  
Unrealistic Assumption ◽  
Plant Respiration ◽  
The Impact

Abstract. Accurately representing the response of ecosystems to environmental change in land surface models (LSMs) is crucial to making accurate predictions of future climate. Many LSMs do not correctly capture plant respiration and growth fluxes, particularly in response to extreme climatic events. This is in part due to the unrealistic assumption that total plant carbon expenditure (PCE) is always equal to gross carbon accumulation by photosynthesis. We present and evaluate a simple model of labile carbon storage and utilisation (SUGAR) designed to be integrated into an LSM, which allows simulated plant respiration and growth to vary independent of photosynthesis. SUGAR buffers simulated PCE against seasonal variation in photosynthesis, producing more constant (less variable) predictions of plant growth and respiration relative to an LSM that does not represent labile carbon storage. This allows the model to more accurately capture observed carbon fluxes at a large-scale drought experiment in a tropical moist forest in the Amazon, relative to the Joint UK Land Environment Simulator LSM (JULES). SUGAR is designed to improve the representation of carbon storage in LSMs and provides a simple framework that allows new processes to be integrated as the empirical understanding of carbon storage in plants improves. The study highlights the need for future research into carbon storage and allocation in plants, particularly in response to extreme climate events such as drought.

scholarly journals The Impact of a Simple Representation of Non-Structural Carbohydrates on the Simulated Response of Tropical Forests to Drought

2019 ◽  
Author(s):  
Simon Jones ◽  
Lucy Rowland ◽  
Peter Cox ◽  
Debbie Hemming ◽  
Andy Wiltshire ◽  
...  
Keyword(s):  
Carbon Storage ◽  
Land Surface ◽  
Large Scale ◽  
Carbon Accumulation ◽  
Future Research ◽  
Labile Carbon ◽  
Moist Forest ◽  
Unrealistic Assumption ◽  
Plant Respiration ◽  
The Impact

Abstract. Accurately representing the response of ecosystems to environmental change in land surface models (LSM) is crucial to making accurate predictions of future climate. Many LSMs do not correctly capture plant respiration and growth fluxes, particularly in response to extreme climatic events. This is in part due to the unrealistic assumption that total plant carbon expenditure (PCE) is always equal to gross carbon accumulation by photosynthesis. We present and evaluate a simple model of labile carbon storage and utilisation (SUGAR), designed to be integrated into an LSM, that allows simulated plant respiration and growth to vary independently of photosynthesis. SUGAR buffers simulated PCE against seasonal variation in photosynthesis, producing more constant (less variable) predictions of plant growth and respiration relative to an LSM that does not represent labile carbon storage. This allows the model to more accurately capture observed carbon fluxes at a large-scale drought experiment in a tropical moist forest in the Amazon, relative to the Joint UK Land Environment Simulator LSM (JULES). SUGAR is designed to improve the representation of carbon storage in LSMs and provides a simple framework that allows new processes to be integrated as the empirical understanding of carbon storage in plants improves. The study highlights the need for future research into carbon storage and allocation in plants, particularly in response to extreme climate events such as drought.

scholarly journals Evaluating the potential of large-scale simulations to predict carbon fluxes of terrestrial ecosystems over a European Eddy Covariance network

2014 ◽  
Vol 11 (10) ◽  
pp. 2661-2678 ◽  
Author(s):  
M. Balzarolo ◽  
S. Boussetta ◽  
G. Balsamo ◽  
A. Beljaars ◽  
F. Maignan ◽  
...  
Keyword(s):  
Eddy Covariance ◽  
Land Surface ◽  
Large Scale ◽  
Meteorological Data ◽  
Model Development ◽  
Vapour Pressure Deficit ◽  
Terrestrial Ecosystems ◽  
Carbon Fluxes ◽  
Simulation Performance ◽  
Large Scale Simulations

Abstract. This paper reports a comparison between large-scale simulations of three different land surface models (LSMs), ORCHIDEE, ISBA-A-gs and CTESSEL, forced with the same meteorological data, and compared with the carbon fluxes measured at 32 eddy covariance (EC) flux tower sites in Europe. The results show that the three simulations have the best performance for forest sites and the poorest performance for cropland and grassland sites. In addition, the three simulations have difficulties capturing the seasonality of Mediterranean and sub-tropical biomes, characterized by dry summers. This reduced simulation performance is also reflected in deficiencies in diagnosed light-use efficiency (LUE) and vapour pressure deficit (VPD) dependencies compared to observations. Shortcomings in the forcing data may also play a role. These results indicate that more research is needed on the LUE and VPD functions for Mediterranean and sub-tropical biomes. Finally, this study highlights the importance of correctly representing phenology (i.e. leaf area evolution) and management (i.e. rotation–irrigation for cropland, and grazing–harvesting for grassland) to simulate the carbon dynamics of European ecosystems and the importance of ecosystem-level observations in model development and validation.

scholarly journals Large-scale overview of the summer monsoon over West Africa during the AMMA field experiment in 2006

2008 ◽  
Vol 26 (9) ◽  
pp. 2569-2595 ◽  
Author(s):  
S. Janicot ◽  
C. D. Thorncroft ◽  
A. Ali ◽  
N. Asencio ◽  
G. Berry ◽  
...  
Keyword(s):  
Summer Monsoon ◽  
Land Surface ◽  
Large Scale ◽  
Monsoon Season ◽  
Regional Scale ◽  
West African ◽  
Future Research ◽  
Atmospheric Conditions ◽  
African Monsoon ◽  
Continental Hydrology

Abstract. The AMMA (African Monsoon Multidisciplinary Analysis) program is dedicated to providing a better understanding of the West African monsoon and its influence on the physical, chemical and biological environment regionally and globally, as well as relating variability of this monsoon system to issues of health, water resources, food security and demography for West African nations. Within this framework, an intensive field campaign took place during the summer of 2006 to better document specific processes and weather systems at various key stages of this monsoon season. This campaign was embedded within a longer observation period that documented the annual cycle of surface and atmospheric conditions between 2005 and 2007. The present paper provides a large and regional scale overview of the 2006 summer monsoon season, that includes consideration of of the convective activity, mean atmospheric circulation and synoptic/intraseasonal weather systems, oceanic and land surface conditions, continental hydrology, dust concentration and ozone distribution. The 2006 African summer monsoon was a near-normal rainy season except for a large-scale rainfall excess north of 15° N. This monsoon season was also characterized by a 10-day delayed onset compared to climatology, with convection becoming developed only after 10 July. This onset delay impacted the continental hydrology, soil moisture and vegetation dynamics as well as dust emission. More details of some less-well-known atmospheric features in the African monsoon at intraseasonal and synoptic scales are provided in order to promote future research in these areas.

scholarly journals Some aspects of ecophysiological and biogeochemical responses of tropical forests to atmospheric change

2004 ◽  
Vol 359 (1443) ◽  
pp. 463-476 ◽  
Author(s):  
Jeffrey Q. Chambers ◽  
Whendee L. Silver
Keyword(s):  
Environmental Factors ◽  
Carbon Storage ◽  
Tropical Forests ◽  
Land Surface ◽  
Net Primary Productivity ◽  
Amazon Forest ◽  
Old Growth ◽  
Individual Tree ◽  
Ecosystem Carbon ◽  
Sequestration Rate

Atmospheric changes that may affect physiological and biogeochemical processes in old–growth tropical forests include: (i) rising atmospheric CO 2 concentration; (ii) an increase in land surface temperature; (iii) changes in precipitation and ecosystem moisture status; and (iv) altered disturbance regimes. Elevated CO 2 is likely to directly influence numerous leaf–level physiological processes, but whether these changes are ultimately reflected in altered ecosystem carbon storage is unclear. The net primary productivity (NPP) response of old–growth tropical forests to elevated CO 2 is unknown, but unlikely to exceed the maximum experimentally measured 25% increase in NPP with a doubling of atmospheric CO 2 from pre–industrial levels. In addition, evolutionary constraints exhibited by tropical plants adapted to low CO 2 levels during most of the Late Pleistocene, may result in little response to increased carbon availability. To set a maximum potential response for a Central Amazon forest, using an individual–tree–based carbon cycling model, a modelling experiment was performed constituting a 25% increase in tree growth rate, linked to the known and expected increase in atmospheric CO 2 . Results demonstrated a maximum carbon sequestration rate of ca . 0.2 Mg C per hectare per year (ha −1 yr −1 , where 1 ha = 10 4 m 2 ), and a sequestration rate of only 0.05 Mg C ha −1 yr −1 for an interval centred on calendar years 1980–2020. This low rate results from slow growing trees and the long residence time of carbon in woody tissues. By contrast, changes in disturbance frequency, precipitation patterns and other environmental factors can cause marked and relatively rapid shifts in ecosystem carbon storage. It is our view that observed changes in tropical forest inventory plots over the past few decades is more probably being driven by changes in disturbance or other environmental factors, than by a response to elevated CO 2 . Whether these observed changes in tropical forests are the beginning of long–term permanent shifts or a transient response is uncertain and remains an important research priority.

scholarly journals Dual state/rainfall correction via soil moisture assimilation for improved streamflow simulation: evaluation of a large-scale implementation with Soil Moisture Active Passive (SMAP) satellite data

2020 ◽  
Vol 24 (2) ◽  
pp. 615-631 ◽  
Author(s):  
Yixin Mao ◽  
Wade T. Crow ◽  
Bart Nijssen
Keyword(s):  
Soil Moisture ◽  
Land Surface ◽  
Large Scale ◽  
Land Surface Model ◽  
Systematic Errors ◽  
Red River ◽  
Future Research ◽  
Surface Model ◽  
Random Errors ◽  
Rainfall Estimates

Abstract. Soil moisture (SM) measurements contain information about both pre-storm hydrologic states and within-storm rainfall estimates, both of which are required inputs for event-based streamflow simulations. In this study, an existing dual state/rainfall correction system is extended and implemented in the 605 000 km2 Arkansas–Red River basin with a semi-distributed land surface model. The Soil Moisture Active Passive (SMAP) satellite surface SM retrievals are assimilated to simultaneously correct antecedent SM states in the model and rainfall estimates from the Global Precipitation Measurement (GPM) mission. While the GPM rainfall is corrected slightly to moderately, especially for larger events, the correction is smaller than that reported in past studies due primarily to the improved baseline quality of the new GPM satellite product. In addition, rainfall correction is poorer in regions with dense biomass due to lower SMAP quality. Nevertheless, SMAP-based dual state/rainfall correction is shown to generally improve streamflow estimates, as shown by comparisons with streamflow observations across eight Arkansas–Red River sub-basins. However, more substantial streamflow correction is limited by significant systematic errors present in model-based streamflow estimates that are uncorrectable via standard data assimilation techniques aimed solely at zero-mean random errors. These findings suggest that more substantial streamflow correction will likely require better quality SM observations as well as future research efforts aimed at reducing systematic errors in hydrologic systems.

scholarly journals Terrestrial Ecosystem Carbon Fluxes Predicted from MODIS Satellite Data and Large-Scale Disturbance Modeling

2012 ◽  
Vol 03 (03) ◽  
pp. 469-479 ◽  
Author(s):  
Christopher Potter ◽  
Steven Klooster ◽  
Vanessa Genovese ◽  
Cyrus Hiatt ◽  
Shyam Boriah ◽  
...  
Keyword(s):  
Satellite Data ◽  
Large Scale ◽  
Terrestrial Ecosystem ◽  
Carbon Fluxes ◽  
Ecosystem Carbon ◽  
Large Scale Disturbance ◽  
Ecosystem Carbon Fluxes

A net ecosystem carbon budget for snow dominated forested headwater catchments: linking water and carbon fluxes to critical zone carbon storage

2018 ◽  
Vol 138 (3) ◽  
pp. 225-243 ◽  
Author(s):  
Julia Perdrial ◽  
Paul D. Brooks ◽  
Tyson Swetnam ◽  
Kathleen A. Lohse ◽  
Craig Rasmussen ◽  
...  
Keyword(s):  
Carbon Storage ◽  
Carbon Budget ◽  
Carbon Fluxes ◽  
Critical Zone ◽  
Headwater Catchments ◽  
Ecosystem Carbon

scholarly journals Evaluating the potential of large scale simulations to predict carbon fluxes of terrestrial ecosystems over a European Eddy Covariance network

2013 ◽  
Vol 10 (7) ◽  
pp. 11857-11897 ◽  
Author(s):  
M. Balzarolo ◽  
S. Boussetta ◽  
G. Balsamo ◽  
A. Beljaars ◽  
F. Maignan ◽  
...  
Keyword(s):  
Eddy Covariance ◽  
Land Surface ◽  
Large Scale ◽  
Meteorological Data ◽  
Vapour Pressure Deficit ◽  
Terrestrial Ecosystems ◽  
Carbon Fluxes ◽  
Simulation Performance ◽  
Research Activities ◽  
Forest Sites

Abstract. Understanding and simulating land biosphere processes happening at the interface between plants and atmosphere are important research activities with operational applications for monitoring and predicting seasonal and inter-annual variability of terrestrial carbon fluxes in connection to a changing climate. This paper reports a comparison between three different Land Surface Models (LSMs), ORCHIDEE, ISBA-A-gs and CTESSEL used in the Copernicus-Land project precursor, forced with the same meteorological data, and compared with the carbon fluxes measured at 32 Eddy Covariance (EC) flux tower sites in Europe. The results show that the three models have the best performance for forest sites and the poorest performance for cropland and grassland sites. In addition, the three models have difficulties capturing the seasonality of Mediterranean and Sub-tropical biomes, characterized by dry summers. This reduced simulation performance is also reflected in deficiencies in diagnosed Light Use Efficiency (LUE) and Vapour Pressure Deficit (VPD) dependencies compared to observations. Shortcomings in the forcing data may also play a role. These results indicate that more research is needed on the LUE and VPD functions for Mediterranean and Sub-tropical biomes. Finally, this study highlights the importance well representing phenology (i.e. Leaf Area evolution) and management (i.e. rotation/irrigation for cropland, and grazing/harvesting for grassland) to simulate the carbon dynamics of European ecosystems and the importance of ecosystem level observation in models development and validation.

scholarly journals The impact of lateral carbon fluxes on the European carbon balance

2008 ◽  
Vol 5 (5) ◽  
pp. 1259-1271 ◽  
Author(s):  
P. Ciais ◽  
A. V. Borges ◽  
G. Abril ◽  
M. Meybeck ◽  
G. Folberth ◽  
...  
Keyword(s):  
Carbon Balance ◽  
Large Scale ◽  
Food Product ◽  
Carbon Fluxes ◽  
Carbon Accumulation ◽  
Main Process ◽  
Carbon Budgets ◽  
Lateral Transport ◽  
Gaseous Species ◽  
The Impact

Abstract. To date, little is known about the impact of processes which cause lateral carbon fluxes over continents, and from continents to oceans on the CO2 – and carbon budgets at local, regional and continental scales. Lateral carbon fluxes contribute to regional carbon budgets as follows: Ecosystem CO2 sink=Ecosystem carbon accumulation+Lateral carbon fluxes. We estimated the contribution of wood and food product trade, of emission and oxidation of reduced carbon species, and of river erosion and transport as lateral carbon fluxes to the carbon balance of Europe (EU-25). The analysis is completed by new estimates of the carbon fluxes of coastal seas. We estimated that lateral transport (all processes combined) is a flux of 165 Tg C yr−1 at the scale of EU-25. The magnitude of lateral transport is thus comparable to current estimates of carbon accumulation in European forests. The main process contributing to the total lateral flux out of Europe is the flux of reduced carbon compounds, corresponding to the sum of non-CO2 gaseous species (CH4, CO, hydrocarbons, ...) emitted by ecosystems and exported out of the European boundary layer by the large scale atmospheric circulation.

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