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Separation of net ecosystem exchange into assimilation and respiration using a light response curve approach: critical issues and global evaluation

The measured net ecosystem exchange (NEE) of CO2 between the ecosystem and the atmosphere reflects the balance between gross CO2 assimilation [gross primary production (GPP)] and ecosystem respiration (R-eco). For understanding the mechanistic responses of ecosystem processes to environmental change it is important to separate these two flux components. Two approaches are conventionally used: (1)

From biota to chemistry and climate: towards a comprehensive description of trace gas exchange between the biosphere and atmosphere

Exchange of non-CO2 trace gases between the land surface and the atmosphere plays an important role in atmospheric chemistry and climate. Recent studies have highlighted its importance for interpretation of glacial-interglacial ice-core records, the simulation of the pre-industrial and present atmosphere, and the potential for large climate-chemistry and climate-aerosol feedbacks in the coming cen

Interdisciplinary approach for reconstructing an alder-based historical agricultural practice of the Eastern Ligurian Apennines (NW Italy)

Data from four soil profiles studied through pollen and macroscopic charcoal analyses were used to identify specific palynological assemblages associated with a traditional land-use system documented in the Eastern Ligurian Apennines (NW Italy) between the 18th and early 20th century, concerning a cyclical use of grey alder plots for temporary cultivations involving to the use of controlled fire.

Can a "state of the art" chemistry transport model simulate Amazonian tropospheric chemistry?

We present an evaluation of a nested high-resolution Goddard Earth Observing System (GEOS)-Chem chemistry transport model simulation of tropospheric chemistry over tropical South America. The model has been constrained with two isoprene emission inventories: (1) the canopy-scale Model of Emissions of Gases and Aerosols from Nature (MEGAN) and (2) a leaf-scale algorithm coupled to the Lund-Potsdam-

Development of a method for monitoring of insect induced forest defoliation – limitation of MODIS data in Fennoscandian forest landscapes

We investigated if coarse-resolution satellite data from the MODIS sensor can be used for regional monitoring of insect disturbances in Fennoscandia. A damage detection method based on z-scores of seasonal maximums of the 2-band Enhanced Vegetation Index (EVI2) was developed. Time-series smoothing was applied and Receiver Operating Characteristics graphs were used for optimisation. The method was

Future vegetation changes in thawing subarctic mires and implications for greenhouse gas exchange-a regional assessment

One of the major concerns regarding climate change in high latitudes is the potential feedback from greenhouse gases (GHG) being released from thawing peat soils. In this paper we show how vegetational patterns and associated GHG fluxes in subarctic palsa (peat mounds with a permanently frozen core) mires can be linked to climate, based on field observations from fifteen palsa sites distributed in

Human impacts and their interactions in the Baltic Sea region

Coastal environments, in particular heavily populated semi-enclosed marginal seas and coasts like the Baltic Sea region, are strongly affected by human activities. A multitude of human impacts, including climate change, affect the different compartments of the environment, and these effects interact with each other. As part of the Baltic Earth Assessment Reports (BEAR), we present an inventory and

Assessment of irrigation and groundwater management strategies in cold arid areas with shallow groundwater tables using a coupled year-round agro-hydrological model

Quantitatively assessing the impact of irrigation and groundwater management strategies is crucial for improving water productivity and soil salinity control in cold arid areas with shallow groundwater tables (CAASGT). However, existing studies often focus on specific periods, either the crop growth period or the freeze–thaw period, due to the lack of appropriate models that can accurately represe

Snow redistribution decreases winter soil carbon loss in the Arctic dry heath tundra

Rapid warming increases winter soil carbon dioxide (CO2) efflux in Arctic tundra ecosystems, which can significantly offset carbon (C) uptake during growing seasons and affect the overall annual C balance. In winter, the Arctic landscape is predominantly covered with snow, which is vital for regulating ecological processes. Nevertheless, the impact of snow redistribution on the spatial distributio

Reconciling East Asia's mid-Holocene temperature discrepancy through vegetation-climate feedback

The term “Holocene temperature conundrum” refers to the inconsistencies between proxy-based reconstructions and transient model simulations, and it challenges our understanding of global temperature evolution during the Holocene. Climate reconstructions indicate a cooling trend following the Holocene Thermal Maximum, while model simulations indicate a consistent warming trend due to ice-sheet retr

Projected future changes in the cryosphere and hydrology of a mountainous catchment in the upper Heihe River, China

Climate warming exacerbates the degradation of the mountain cryosphere, including glacier retreat, permafrost degradation, and snow cover reduction. These changes dramatically alter the local and downstream hydrological regime, posing significant threats to basin-scale water resource management and sustainable development. However, this issue is still not adequately addressed, particularly in moun

Climate change impacts on long-term forest productivity might be driven by species turnover rather than by changes in tree growth

Aim: Climate change impacts forest functioning and services through two inter-related effects. First, it impacts tree growth, with effects, for example, on biomass production. Second, climate change also reshuffles community composition, with further effects on forest functioning. However, the relative importance of these two effects has rarely been studied. Here, we developed a new modelling appr

Impacts of Spartina alterniflora invasion on coastal carbon cycling within a native Phragmites australis-dominated wetland

Despite its significance for climate adaptation, the impact of non-native Spartina alterniflora on coastal blue carbon cycling remains unclear. While it is generally reported that S. alterniflora invasion increases the soil organic carbon (SOC) stock along China's coastlines from tropical to subtropical climate zones, some cases, such as the Jiuduansha wetland in the Yangtze River estuary, show a

Hiking Trails Facilitate the Spread of a Native High-Arctic Species

High-Arctic environments are facing an elevated pace of warming and increasing human activities, making them more susceptible to the introduction and spread of alien species. We investigated the role of human disturbance in facilitating the spread of a native plant (Papaver dahlianum) in a high-Arctic natural environment close to Isfjord Radio station and along adjacent hiking trails at Kapp Linné

Advancing hydrological modeling through multivariate calibration of multi-layer soil moisture dynamics

Study region: The Meichuan Basin, China Study focus: Soil water processes are critical in hydrological modeling, yet most studies focus on surface moisture due to data limitations, which hampers accurate simulations of root zone soil moisture dynamics. To address this gap, we developed three calibration schemes: M1 and M2, two benchmarks that rely solely on traditional streamflow data and incorpor

Assessing recovery time of ecosystems in China : insights into flash drought impacts on gross primary productivity

Recovery time, referring to the duration that an ecosystem needs to return to its pre-drought condition, is a fundamental indicator of ecological resilience. Recently, flash droughts – characterised by rapid onset and development – have gained increasing attention. Nevertheless, the spatiotemporal patterns in gross primary productivity (GPP) recovery time and the factors influencing it remain larg

Effects of moisture dynamics on bryophyte carbon fluxes in a tropical cloud forest

Bryophytes play key roles in the ecological function of a number of major world biomes but remain understudied compared with vascular plants. Little is known about bryophyte responses to different aspects of predicted changes in moisture dynamics with climate change. In this study, CO 2 fluxes and photosynthetic light responses were measured within bryophyte mesocosms, being subjected to differe

An interactive tool to analyse the benefit of space missions sensing the terrestrial vegetation

The study has developed an interactive mission benefit analysis (MBA) tool that allows instantaneous evaluation of a range of potential mission designs. The designs are evaluated in terms of their constraint on carbon and water fluxes through calibration of a terrestrial bisphere model. The constraint is quantified by methematically rigorous uncertainty propagation in CCDAS. Applying the MBA tool,

Ecosystem carbon response of an Arctic peatland to simulated permafrost thaw

Permafrost peatlands are biogeochemical hot spots in the Arctic as they store vast amounts of carbon. Permafrost thaw could release part of these long-term immobile carbon stocks as the greenhouse gases (GHGs) carbon dioxide (CO 2 ) and methane (CH 4 ) to the atmosphere, but how much, at which time-span and as which gaseous carbon species is still highly uncertain. Here we assess the effect of