193 research outputs found
Radiative transfer modeling through terrestrial atmosphere and ocean accounting for inelastic scattering processes: Software package SCIATRAN.
SCIATRAN is a comprehensive software package which is designed to model radiative transfer processes in the terrestrial atmosphere and ocean in the spectral range from the ultraviolet to the thermal infrared (0.18–40 μm). It accounts for multiple scattering processes, polarization, thermal emission and ocean–atmosphere coupling. The main goal of this paper is to present a recently developed version of SCIATRAN which takes into account accurately inelastic radiative processes in both the atmosphere and the ocean. In the scalar version of the coupled ocean–atmosphere radiative transfer solver presented by Rozanov et al. [61] we have implemented the simulation of the rotational Raman scattering, vibrational Raman scattering, chlorophyll and colored dissolved organic matter fluorescence.
In this paper we discuss and explain the numerical methods used in SCIATRAN to solve the scalar radiative transfer equation including trans-spectral processes, and demonstrate how some selected radiative transfer problems are solved using the SCIATRAN package. In addition we present selected comparisons of SCIATRAN simulations with those published benchmark results, independent radiative transfer models, and various measurements from satellite, ground-based, and ship-borne instruments.
The extended SCIATRAN software package along with a detailed User's Guide is made available for scientists and students, who are undertaking their own research typically at universities, via the web page of the Institute of Environmental Physics (IUP), University of Bremen: http://www.iup.physik.uni-bremen.de
Retrieval of Terrestrial Plant Fluorescence based on the in-filling of far-red Fraunhofer lines using SCIAMACHY Observations
Synergistic exploitation of hyper- and multispectral Sentinel measurements to determine Phytoplankton Functional Types at best spatial and temporal resolution (SynSenPFT)
We derive the chlorophyll a concentration (Chla) for three main phytoplankton functional types (PFTs) – diatoms, coccolithophores and cyanobacteria – by combining satellite multispectral-based information, being of a high spatial and temporal resolution, with retrievals based on high resolution of PFT absorption properties derived from hyperspectral satellite measurements. The multispectral-based PFT Chla retrievals are based on a revised version of the empirical OC-PFT algorithm applied to the Ocean Color Climate Change Initiative (OC-CCI) total Chla product. The PhytoDOAS analytical algorithm is used with some modifications to derive PFT Chla from SCIAMACHY hyperspectral measurements. To combine synergistically these two PFT products (OC-PFT and PhytoDOAS), an optimal interpolation is performed for each PFT in every OC-PFT sub-pixel within a PhytoDOAS pixel, given its Chla and its a priori error statistics. The synergistic product (SynSenPFT) is presented for the period of August 2002 March 2012 and evaluated against PFT Chla data obtained from in situ marker pigment data and the NASA Ocean Biogeochemical Model simulations and satellite information on phytoplankton size. The most challenging aspects of the SynSenPFT algorithm implementation are discussed. Perspectives on SynSenPFT product improvements and prolongation of the time series over the next decades by adaptation to Sentinel multi- and hyperspectral instruments are highlighted
A Critical Analysis of Bumblefoot: Care and Preventative Measures in Captive Penguins
Bumblefoot is a progressive and sometimes deadly infection that afflicts penguins living in human care. The most prominent cause of the disease is the extended amount of time that captive penguins spend standing in comparison to their pelagic and wild counterparts. For years, facilities have treated bumblefoot with surgery and antibiotics. However, this approach is palliative rather than preventative and has become problematic as bacteria develop stronger resistance to antibiotics. To address the behavioral abnormalities underlying the onset of bumblefoot, zoos and aquariums should utilize environmental enrichment. Many forms of environmental enrichment, including the relationship penguins have with their keepers and colored balls or rings, may prove effective at encouraging these aquatic birds to spend more time in the water. However, few studies have worked to determine the effectiveness of environmental enrichment as a preventative measure for bumblefoot. When used in addition to behavioral husbandry, or the training associated with achieving the voluntarily participation of penguins in their daily care, environmental enrichment may be the key to eradicating bumblefoot from the lives of captive penguins while also providing them with a more stimulating and healthier environment
Role of the PAS sensor domains in the Bacillus subtilis sporulation kinase KinA
Histidine kinases are sophisticated molecular sensors that are used by bacteria to detect and respond to a multitude of environmental signals. KinA is the major histidine kinase required for initiation of sporulation upon nutrient deprivation in Bacillus subtilis. KinA has a large N-terminal region (residues 1 to 382) that is uniquely composed of three tandem Per-ARNT-Sim (PAS) domains that have been proposed to constitute a sensor module. To further enhance our understanding of this "sensor" region, we defined the boundaries that give rise to the minimal autonomously folded PAS domains and analyzed their homo- and heteroassociation properties using analytical ultracentrifugation, nuclear magnetic resonance (NMR) spectroscopy, and multiangle laser light scattering. We show that PAS(A) self-associates very weakly, while PAS(C) is primarily a monomer. In contrast, PAS(B) forms a stable dimer (K-d [dissociation constant] o
Investigation of spectral band requirements for improving retrievals of phytoplankton functional types.
Studying phytoplankton functional types (PFTs) from space is possible due to recent advances in remote sensing. Though a variety of products are available, the limited number of wavelengths available compared to the number of model parameters needed to be retrieved is still a major problem in using ocean-color data for PFT retrievals. Here, we investigated which band placement could improve retrievals of three particular PFTs (diatoms, coccolithophores and cyanobacteria). In addition to analyzing dominant spectral features in the absorption spectra of the target PFTs, two previously-developed methods using measured spectra were applied to simulated data. Such a synthetic dataset allowed for significantly increasing the number of scenarios and
enabled a full control over parameters causing spectral changes. We evaluated the chosen band placement by applying an adapted ocean reflectance inversion, as utilized in the generalized inherent optical properties (GIOP) retrieval. Results show that the optimal band settings depend on the method applied to determine the bands placement, as well as on the internal variability of the dataset investigated. Therefore, continuous hyperspectral instruments would be most beneficial for discriminating multiple PFTs, though a small improvement in spectral sampling and resolution does not significantly modify the results. Bands, which could be added to future instruments (e.g., Ocean and Land Colour Instrument (OLCI) instrument on the upcoming Sentinel-3B,-3C,-3D, etc., and further satellites) in order to enhance PFT retrieval capabilities, were also determined
Corrigendum: Synergistic exploitation of hyper- and multi-spectral precursor sentinel measurements to determine phytoplankton functional types (SynSenPFT) [Front. Mar. Sci,(203),4] DOI: 10.3389/fmars.2017.00203
This is the final version. Available on open access from Frontiers Media via the DOI in this recordThe article to which this is the corrigendum is in ORE at http://hdl.handle.net/10871/38250In the original article, we neglected, but would like to acknowledge the North-German Supercomputing Alliance (HLRN) for providing HPC resources that have contributed to the research results reported in this paper. The authors apologize for this error and state that this does not change the scientific conclusions of the article in any way
Synergistic exploitation of hyper- and multi-spectral precursor sentinel measurements to determine phytoplankton functional types (SynSenPFT)
This is the final version. Available from Frontiers Media via the DOI in this record.The corrigendum to this article is in ORE at http://hdl.handle.net/10871/38256We derive the chlorophyll a concentration (Chla) for three main phytoplankton functional types (PFTs) - diatoms, coccolithophores and cyanobacteria - by combining satellite multispectral-based information, being of a high spatial and temporal resolution, with retrievals based on high resolution of PFT absorption properties derived from hyperspectral satellite measurements. The multispectral-based PFT Chla retrievals are based on a revised version of the empirical OC-PFT algorithm applied to the Ocean Color Climate Change Initiative (OC-CCI) total Chla product. The PhytoDOAS analytical algorithm is used with some modifications to derive PFT Chla from SCIAMACHY hyperspectral measurements. To combine synergistically these two PFT products (OC-PFT and PhytoDOAS), an optimal interpolation is performed for each PFT in every OC-PFT sub-pixel within a PhytoDOAS pixel, given its Chla and its a priori error statistics. The synergistic product (SynSenPFT) is presented for the period of August 2002 March 2012 and evaluated against PFT Chla data obtained from in situ marker pigment data and the NASA Ocean Biogeochemical Model simulations and satellite information on phytoplankton size. The most challenging aspects of the SynSenPFT algorithm implementation are discussed. Perspectives on SynSenPFT product improvements and prolongation of the time series over the next decades by adaptation to Sentinel multi- and hyperspectral instruments are highlighted.ESA SEOM SY-4Sci Synergy projectSFB/TR 172 (AC)3 “Arctic Amplification” subproject C03DFG-Priority Program SPP 1158 “Antarktis” PhySyn BU2913/3-1Helmholtz Climate Initiative REKLIMHelmholtz Association of German Research Centres (HGF
Men, Mental Health and Elite Sport: a Narrative Review
Mental health in elite sport is receiving more publicity due to an increase in male athletes sharing their personal experiences. Sports injury is recognised as the major risk factor for psychological distress amongst male athletes, although anecdotally this may be that athletes are more likely to discuss their emotional wellbeing when related to the injury they are experiencing. Stress can be amplified within elite sport and the pressure they experience in relation to competition and performance can be exacerbated by adverse life events. This ongoing stress does not end when their sporting career does, it can follow them into retirement. The physical and psychological demands placed upon them by the sporting environment may predispose athletes to developing depression. As an athlete's symptoms of mental illness intensify, their performance can be negatively affected leaving them vulnerable and exposed to further symptoms of common mental disorders. The pressure of performance can also expose male athletes to overtraining syndrome which can be difficult to distinguish from depression. Male athletes are more vulnerable to eating disorders compared with males in the general population and they do have anxieties, particularly around their bodies, but find it difficult to disclose their concerns. In addition to this, male athletes are more likely to use substances, including opioids to improve both sport and non-sport performance.Despite the prevalence of common mental disorders in male athletes, stigma still exists, and although some athletes discuss their issues publicly after their career has ended, the majority of athletes prefer to remain silent. There remains a view that athletes who seek help for psychological problems may be seen as weak. Although there is an improvement in help-seeking attitudes within elite sport, further research and education is needed to encourage men to talk about their mental health, share their experiences and to enjoy a greater sense of emotional wellbeing
Assessing the dynamics of vegetation productivity in circumpolar regions with different satellite indicators of greenness and photosynthesis
High-latitude treeless ecosystems represent spatially highly heterogeneous
landscapes with small net carbon fluxes and a short growing season. Reliable
observations and process understanding are critical for projections of the
carbon balance of the climate-sensitive tundra. Space-borne remote sensing is the
only tool to obtain spatially continuous and temporally resolved information
on vegetation greenness and activity in remote circumpolar areas. However,
confounding effects from persistent clouds, low sun elevation angles,
numerous lakes, widespread surface inundation, and the sparseness of the
vegetation render it highly challenging. Here, we conduct an extensive
analysis of the timing of peak vegetation productivity as shown by satellite
observations of complementary indicators of plant greenness and
photosynthesis. We choose to focus on productivity during the peak of the
growing season, as it importantly affects the total annual carbon uptake. The
suite of indicators are as follows: (1) MODIS-based vegetation indices (VIs) as proxies
for the fraction of incident photosynthetically active radiation (PAR) that is absorbed (fPAR), (2) VIs combined with estimates
of PAR as a proxy of the total absorbed radiation (APAR), (3) sun-induced chlorophyll fluorescence (SIF) serving as a proxy
for photosynthesis, (4) vegetation optical depth (VOD), indicative of total
water content and (5) empirically upscaled modelled gross primary
productivity (GPP). Averaged over the pan-Arctic we find a clear order of the
annual peak as APAR ≦ GPP < SIF < VIs∕VOD. SIF as an indicator of
photosynthesis is maximised around the time of highest annual temperatures.
The modelled GPP peaks at a similar time to APAR. The time lag of the annual peak
between APAR and instantaneous SIF fluxes indicates that the SIF data do
contain information on light-use efficiency of tundra vegetation, but further
detailed studies are necessary to verify this. Delayed peak greenness
compared to peak photosynthesis is consistently found across years and land-cover classes. A particularly late peak of the normalised difference
vegetation index (NDVI) in regions with very small seasonality in greenness
and a high amount of lakes probably originates from artefacts. Given the very
short growing season in circumpolar areas, the average time difference in
maximum annual photosynthetic activity and greenness or growth of 3 to 25 days
(depending on the data sets chosen) is important and needs to be considered
when using satellite observations as drivers in vegetation models.</p
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