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Do we (need to) care about canopy radiation schemes in DGVMs? Caveats and potential impacts
Dynamic global vegetation models (DGVMs) are an essential part of current state-of-the-art Earth system models. In recent years, the complexity of DGVMs has increased by incorporating new important processes like, e.g., nutrient cycling and land cover dynamics, while biogeophysical processes like surface radiation have not been developed much further. Canopy radiation models are however very important for the estimation of absorption and reflected fluxes and are essential for a proper estimation of surface carbon, energy and water fluxes.
The present study provides an overview of current implementations of canopy radiation schemes in a couple of state-of-the-art DGVMs and assesses their accuracy in simulating canopy absorption and reflection for a variety of different surface conditions. Systematic deviations in surface albedo and fractions of absorbed photosynthetic active radiation (faPAR) are identified and potential impacts are assessed.
The results show clear deviations for both, absorbed and reflected, surface solar radiation fluxes. FaPAR is typically underestimated, which results in an underestimation of gross primary productivity (GPP) for the investigated cases. The deviation can be as large as 25% in extreme cases. Deviations in surface albedo range between −0.15 ≤ Δα ≤ 0.36, with a slight positive bias on the order of Δα ≈ 0.04. Potential radiative forcing caused by albedo deviations is estimated at −1.25 ≤ RF ≤ −0.8 (W m−2), caused by neglect of the diurnal cycle of surface albedo.
The present study is the first one that provides an assessment of canopy RT schemes in different currently used DGVMs together with an assessment of the potential impact of the identified deviations. The paper illustrates that there is a general need to improve the canopy radiation schemes in DGVMs and provides different perspectives for their improvement
Bacterial abundance and pH associate with eDNA degradation in water from various aquatic ecosystems in a laboratory setting
Environmental Biolog
The particle size distribution of environmental DNA varies with species and degradation
Environmental Biolog
Methane emissions from floodplains in the Amazon Basin: challenges in developing a process-based model for global applications
Tropical wetlands are estimated to represent about 50% of the natural
wetland methane (CH<sub>4</sub>) emissions and explain a large fraction of the
observed CH<sub>4</sub> variability on timescales ranging from
glacial–interglacial cycles to the currently observed year-to-year
variability. Despite their importance, however, tropical wetlands are poorly
represented in global models aiming to predict global CH<sub>4</sub> emissions.
This publication documents a first step in the development of a process-based
model of CH<sub>4</sub> emissions from tropical floodplains for global
applications. For this purpose, the LPX-Bern Dynamic Global Vegetation Model
(LPX hereafter) was slightly modified to represent floodplain hydrology,
vegetation and associated CH<sub>4</sub> emissions. The extent of tropical
floodplains was prescribed using output from the spatially explicit hydrology
model PCR-GLOBWB. We introduced new plant functional types (PFTs) that
explicitly represent floodplain vegetation. The PFT parameterizations were
evaluated against available remote-sensing data sets (GLC2000 land cover and
MODIS Net Primary Productivity). Simulated CH<sub>4</sub> flux densities were
evaluated against field observations and regional flux inventories. Simulated
CH<sub>4</sub> emissions at Amazon Basin scale were compared to model simulations
performed in the WETCHIMP intercomparison project. We found that LPX
reproduces the average magnitude of observed net CH<sub>4</sub> flux densities for
the Amazon Basin. However, the model does not reproduce the variability
between sites or between years within a site. Unfortunately, site information
is too limited to attest or disprove some model features. At the Amazon Basin
scale, our results underline the large uncertainty in the magnitude of
wetland CH<sub>4</sub> emissions. Sensitivity analyses gave insights into the main
drivers of floodplain CH<sub>4</sub> emission and their associated uncertainties.
In particular, uncertainties in floodplain extent (i.e., difference between
GLC2000 and PCR-GLOBWB output) modulate the simulated emissions by a factor
of about 2. Our best estimates, using PCR-GLOBWB in combination with GLC2000,
lead to simulated Amazon-integrated emissions of
44.4 ± 4.8 Tg yr<sup>−1</sup>. Additionally, the LPX emissions are highly
sensitive to vegetation distribution. Two simulations with the same mean PFT
cover, but different spatial distributions of grasslands within the basin,
modulated emissions by about 20%. Correcting the LPX-simulated NPP using
MODIS reduces the Amazon emissions by 11.3%. Finally, due to an
intrinsic limitation of LPX to account for seasonality in floodplain extent,
the model failed to reproduce the full dynamics in CH<sub>4</sub> emissions but we
proposed solutions to this issue. The interannual variability (IAV) of the
emissions increases by 90% if the IAV in floodplain extent is accounted
for, but still remains lower than in most of the WETCHIMP models. While our
model includes more mechanisms specific to tropical floodplains, we were
unable to reduce the uncertainty in the magnitude of wetland CH<sub>4</sub>
emissions of the Amazon Basin. Our results helped identify and prioritize
directions towards more accurate estimates of tropical CH<sub>4</sub> emissions,
and they stress the need for more research to constrain floodplain CH<sub>4</sub>
emissions and their temporal variability, even before including other
fundamental mechanisms such as floating macrophytes or lateral water fluxes
The crystal structure of the 2:3 complex of rubidium and 7,7,8,8-tetracyanoquinodimethane, Rb 2
Franchising:essence and accounting prosedure
У статті досліджено теоретичні аспекти франчайзингових операцій, визначено переваги і недоліки для учасників договору франчайзингу. Проаналізовано підходи науковців до методики відображення франчайзингу в обліку.This paper investigates the theoretical aspects of franchise operations, advantages and disadvantages for participants of the franchising agreement. Analysis of scientific approaches to accounting procedure of franchising is give
Barriers and Facilitators to the Implementation of the Early-Onset Sepsis Calculator:A Multicenter Survey Study
Prior studies demonstrated the neonatal early-onset sepsis (EOS) calculator’s potential in drastically reducing antibiotic prescriptions, and its international adoption is increasing rapidly. To optimize the EOS calculator’s impact, successful implementation is crucial. This study aimed to identify key barriers and facilitators to inform an implementation strategy. A multicenter cross-sectional survey was carried out among physicians, residents, nurses and clinical obstetricians of thirteen Dutch hospitals. Survey development was prepared through a literature search and stakeholder interviews. Data collection and analysis were based on the Consolidated Framework for Implementation Research (CFIR). A total of 465 stakeholders completed the survey. The main barriers concerned the expectance of the department’s capacity problems and the issues with maternal information transfer between departments. Facilitators concerned multiple relative advantages of the EOS calculator, including stakeholder education, EOS calculator integration in the electronic health record and existing positive expectations about the safety and effectivity of the calculator. Based on these findings, tailored implementation interventions can be developed, such as identifying early adopters and champions, conducting educational meetings tailored to the target group, creating ready-to-use educational materials, integrating the EOS calculator into electronic health records, creating a culture of collective responsibility among departments and collecting data to evaluate implementation success and innovation results.</p
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