Marilyn Roland
A5007752441- Plant Water Relations and Carbon Dynamics
- Atmospheric and Environmental Gas Dynamics
- Climate variability and models
- Plant responses to elevated CO2
- Forest ecology and management
- Soil Carbon and Nitrogen Dynamics
- Soil and Unsaturated Flow
- Geology and Paleoclimatology Research
- Hydrology and Drought Analysis
- Fire effects on ecosystems
- Atmospheric chemistry and aerosols
- Meteorological Phenomena and Simulations
- Forest Management and Policy
- Ionosphere and magnetosphere dynamics
- Methane Hydrates and Related Phenomena
- Geological and Geochemical Analysis
- Peatlands and Wetlands Ecology
- Rice Cultivation and Yield Improvement
- Remote Sensing in Agriculture
- CO2 Sequestration and Geologic Interactions
- Hydrocarbon exploration and reservoir analysis
- Tree-ring climate responses
- Urban Heat Island Mitigation
- Leaf Properties and Growth Measurement
- Bioenergy crop production and management
University of Antwerp
2016-2025
Roland Mills United (Germany)
2015
St. Remigius Krankenhaus Opladen
1980
In summer 2018, Europe experienced a record drought, but it remains unknown how the drought affected ecosystem carbon dynamics. Using observations from 34 eddy covariance sites in different biomes across Europe, we studied sensitivity of gross primary productivity (GPP) to environmental drivers during 2018 versus reference 2016. We found greater drought-induced decline GPP grasslands (-38%) than forests (-10%), which coincided with reduced evapotranspiration and soil water content (SWC). As...
Abstract. Mapping in-situ eddy covariance measurements of terrestrial land-atmosphere fluxes to the globe is a key method for diagnosing Earth system from data-driven perspective. We describe first global products (called X-BASE) newly implemented up-scaling framework, FLUXCOM-X. The X-BASE comprise estimates CO2 net ecosystem exchange (NEE), gross primary productivity (GPP) as well evapotranspiration (ET) and, time, novel fully transpiration product (ETT), at high spatial (0.05°) and...
Abstract. Mapping in situ eddy covariance measurements of terrestrial land–atmosphere fluxes to the globe is a key method for diagnosing Earth system from data-driven perspective. We describe first global products (called X-BASE) newly implemented upscaling framework, FLUXCOM-X, representing an advancement previous generation FLUXCOM terms flexibility and technical capabilities. The X-BASE are comprised estimates CO2 net ecosystem exchange (NEE), gross primary productivity (GPP),...
Drought and heat events, such as the 2018 European drought, interact with exchange of energy between land surface atmosphere, potentially affecting albedo, sensible latent fluxes, well CO2 exchange. Each these quantities may aggravate or mitigate heat, their side effects on productivity, water scarcity global warming. We used measurements 56 eddy covariance sites across Europe to examine response fluxes extreme drought prevailing most year how differed various ecosystem types (forests,...
Severe drought events are known to cause important reductions of gross primary productivity ( GPP ) in forest ecosystems. However, it is still unclear whether this reduction originates from stomatal closure (Stomatal Origin Limitation) and/or non-stomatal limitations (Non-SOL). In study, we investigated the impact edaphic 2018 on and its origin (SOL, NSOL) using a dataset 10 European ecosystem flux towers. all stations where were observed during drought, these largely explained by declines...
Abstract. CO2 exchange between terrestrial ecosystems and the atmosphere is key to understanding feedbacks climate change land surface. In regions with carbonaceous parent material, patterns occur that cannot be explained by biological processes, such as disproportionate outgassing during daytime or nighttime uptake periods when all vegetation senescent. Neither of these phenomena can attributed carbonate weathering reactions, since their rates are too small. Soil ventilation induced high...
Abstract Soil respiration and its biotic abiotic drivers have been an important research topic in recent years. While the bulk of these efforts has focused on emission CO 2 from soils, production subsequent transport soil to atmosphere received far less attention. However, understand processes underlying emissions terrestrial ecosystems, both need be fully evaluated. In this study, we tested what extent a grassland site Austrian Alps could modeled based common assumption that diffusion is...
Abstract. Compared to drought and heat waves, the impact of winter warming on forest CO2 fluxes has been less studied, despite its significant relevance in colder regions with higher soil carbon content. Our objective was test effect exceptionally warm 2020 budget cold-adapted evergreen needleleaf forests across Europe identify contribution climate factors changes fluxes. hypothesis that leads emissions sites due increased ecosystem respiration. To this hypothesis, we used 98 site-year eddy...
Abstract A long‐standing challenge in studying the global carbon cycle has been understanding factors controlling inter–annual variation (IAV) of fluxes, and improving their representations existing biogeochemical models. Here, we compared an optimality‐based model a semi‐empirical light use efficiency to understand how current models can be improved simulate IAV gross primary production (GPP). Both simulated hourly GPP were parameterized for (a) each site–year, (b) site with additional...
Abstract The agreement of Leaf Area Index (LAI) assessments from three indirect methods, i.e. the LAI–2200 Plant Canopy Analyzer, SS1 SunScan Analysis System and Digital Hemispherical Photography (DHP) was evaluated for four canopy types, a short rotation coppice plantation (SRC) with poplar, Scots pine stand, Pedunculate oak stand maize field. In SRC in field, measurements were compared direct (litter fall harvesting). low LAI range (0 to 2) discrepancies partly explained by inability...
Northern forest soils are a major carbon (C) reservoir of global importance. To estimate how the C balance in these will change, roles tree roots and soil microbes should first be decoupled. This study determined activity heterotrophs together with root-associated rhizosphere varies coniferous boreal, hemiboreal, temperate climates along latitudinal gradient using trenching approach. We created experimental plots without living roots, measured respiration (CO2 efflux) from unmanipulated...
Simulating the carbon-water fluxes at more widely distributed meteorological stations based on sparsely and unevenly eddy covariance flux is needed to accurately understand cycle of terrestrial ecosystems. We established a new framework consisting machine learning, determination coefficient (R2), Euclidean distance, remote sensing (RS), simulate daily net ecosystem carbon dioxide exchange (NEE) water (WF) Eurasian using random forest model or/and RS. The NEE WF datasets with RS-based...
Surface albedo is a fundamental radiative parameter as it controls the Earth’s energy budget and directly affects climate. Satellite observations have long been used to capture temporal spatial variations of surface because their continuous global coverage. However, space-based products are often affected by errors in atmospheric correction, multi-angular bi-directional reflectance distribution function (BRDF) modelling, well spectral conversions. To validate products, an situ tower...
Vegetation indices (VIs) derived from optical sensors have been used as proxies for monitoring gross primary productivity (GPP). In contrast to satellite-based VIs, whose temporal resolution is typically limited, especially in cloudy areas, situ VIs may higher resolution. This fine frequency implies much larger sample sizes test the performance of by comparing with eddy covariance-based GPP estimates. Here, we tested potential measured estimate a temperate heathland ecosystem. We compared...
Carbon dioxide (CO2) uptake by plant photosynthesis, referred to as gross primary production (GPP) at the ecosystem level, is sensitive environmental factors, including pollutant exposure, uptake, and changes in scattering of solar shortwave irradiance (SWin) - energy source for photosynthesis. The 2020 spring lockdown due COVID-19 resulted improved air quality atmospheric transparency, providing a unique opportunity assess impact pollutants on terrestrial functioning. However, detecting...
Abstract. High stomatal ozone (O3) uptake has been shown to negatively affect crop yields and the growth of tree seedlings. However, little is known about effect O3 on carbon by mature forest trees. This study investigated high events gross primary productivity (GPP) for a Scots pine stand near Antwerp, Belgium over period 1998–2013. Stomatal fluxes were modelled using in situ mixing ratio measurements multiplicative model, which was parameterised validated this stand. Ozone-induced GPP...
Abstract. Relative to drought and heat waves, the effect of winter warming on forest CO2 fluxes during dormant season has less been investigated, despite its relevance for net uptake in colder regions with higher carbon content soils. Our objective was test exceptionally warm 2020 budget cold-adapted evergreen needle-leaf forests across Europe, identify contribution soil air temperature changes response warming. hypothesis that leads emissions sites due increased ecosystem respiration. To...
Abstract. CO2 exchange between terrestrial ecosystems and the atmosphere is key to understanding feedbacks climate change land surface. In regions with carbonaceous parent material, patterns occur that cannot be explained by biological processes, such as disproportionate outgassing during daytime or nighttime uptake periods when all vegetation senescent. Neither of these phenomena can attributed carbonate weathering reactions, since their rates are too small. Soil ventilation induced high...