scholarly journals Using passive and active microwave observations to constrain ice particle models

2019 ◽  
Author(s):  
Robin Ekelund ◽  
Patrick Eriksson ◽  
Simon Pfreundschuh
Keyword(s):  
Deep Convection ◽  
Microwave Remote Sensing ◽  
Single Scattering ◽  
The Other ◽  
Scattering Data ◽  
Particle Model ◽  
Large Set ◽  
Model Framework ◽  
Statistical Point ◽  
The One

Abstract. Satellite microwave remote sensing is an important tool for determining the distribution of atmospheric ice globally. The upcoming Ice Cloud Imager (ICI) sensor will provide unprecedented measurements at sub-millimetre frequencies, employing channels up to 664 GHz. However, the utilization of such measurements requires detailed data on how individual ice particles scatter and absorb radiation, i.e., single scattering data. Several single scattering databases are currently available, with the one by Eriksson et al. (2018) specifically tailored to ICI. This study attempts to validate and constrain the large set of particle models available in this database, to a smaller and more manageable set. A combined active and passive model framework is developed and employed, which converts CloudSat observations to simulated brightness temperatures (TBs) measured by the GPM Microwave Imager (GMI) and ICI. Simulations covering about one month in the tropic pacific ocean are performed, assuming different microphysical settings realized as combinations of particle model and particle size distribution (PSD). Firstly, it is found that when the CloudSat inversions and passive forward model are considered separately, assumed particle model and PSD have a considerable impact on both radar retrieved ice water content (IWC) and simulated TBs. Conversely, when the combined active and passive framework is employed instead, the uncertainty due to assumed particle model is significantly reduced, essentially due to a compensation effect between bulk extinction at passive frequencies and radar reflectivity. Furthermore, simulated TBs for almost all the tested microphysical combinations, from a statistical point of view, agree well with GMI measurements (186.31 and 190.31 GHz), indicating the robustness of the simulations. However, it is difficult to identify a particle model that outperforms any other. One aggregate particle model, composed of columns, yields marginally better agreement to GMI compared to the other particles, mainly for the most severe cases of deep convection. Of tested PSDs, the one by McFarquhar and Heymsfield (1997) is found to give the best overall agreement to GMI and also yields radar dBZ-IWC relationships closely matching measurements by Protat et al. (2016). Only one particle, modelled as an air-ice mixture spheroid, performs poorly overall. On the other hand, simulations at the higher ICI frequencies (328.65, 334.65, and 668.2 GHz) show significantly higher sensitivity to the assumed particle model. This study thus points to the potential use of combined ICI and 94 GHz radar measurements to constrain ice hydrometeor properties in radiative transfer (RT), using the method demonstrated in this paper.

scholarly journals Using passive and active observations at microwave and sub-millimetre wavelengths to constrain ice particle models

2020 ◽  
Vol 13 (2) ◽  
pp. 501-520 ◽  
Author(s):  
Robin Ekelund ◽  
Patrick Eriksson ◽  
Simon Pfreundschuh
Keyword(s):  
Deep Convection ◽  
Microwave Remote Sensing ◽  
Single Scattering ◽  
The Other ◽  
Scattering Data ◽  
Particle Model ◽  
Large Set ◽  
Model Framework ◽  
Statistical Point ◽  
The One

Abstract. Satellite microwave remote sensing is an important tool for determining the distribution of atmospheric ice globally. The upcoming Ice Cloud Imager (ICI) will provide unprecedented measurements at sub-millimetre frequencies, employing channels up to 664 GHz. However, the utilization of such measurements requires detailed data on how individual ice particles scatter and absorb radiation, i.e. single scattering data. Several single scattering databases are currently available, with the one by Eriksson et al. (2018) specifically tailored to ICI. This study attempts to validate and constrain the large set of particle models available in this database to a smaller and more manageable set. A combined active and passive model framework is developed and employed, which converts CloudSat observations to simulated brightness temperatures (TBs) measured by the Global Precipitation Measurement (GPM) Microwave Imager (GMI) and ICI. Simulations covering about 1 month in the tropical Pacific Ocean are performed, assuming different microphysical settings realized as combinations of the particle model and particle size distribution (PSD). Firstly, it is found that when the CloudSat inversions and the passive forward model are considered separately, the assumed particle model and PSD have a considerable impact on both radar-retrieved ice water content (IWC) and simulated TBs. Conversely, when the combined active and passive framework is employed instead, the uncertainty due to the assumed particle model is significantly reduced. Furthermore, simulated TBs for almost all the tested microphysical combinations, from a statistical point of view, agree well with GMI measurements (166, 186.31, and 190.31 GHz), indicating the robustness of the simulations. However, it is difficult to identify a particle model that outperforms any other. One aggregate particle model, composed of columns, yields marginally better agreement with GMI compared to the other particles, mainly for the most severe cases of deep convection. Of the tested PSDs, the one by McFarquhar and Heymsfield (1997) is found to give the best overall agreement with GMI and also yields radar dBZ–IWC relationships closely matching measurements by Protat et al. (2016). Only one particle, modelled as an air–ice mixture spheroid, performs poorly overall. On the other hand, simulations at the higher ICI frequencies (328.65, 334.65, and 668.2 GHz) show significantly higher sensitivity to the assumed particle model. This study thus points to the potential use of combined ICI and 94 GHz radar measurements to constrain ice hydrometeor properties in radiative transfer (RT) using the method demonstrated in this paper.

scholarly journals Analysis of the Viability of a Photovoltaic Greenhouse with Semi-Transparent Amorphous Silicon (a-Si) Glass

Agronomy ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1097
Author(s):  
José-Ramón Aira ◽  
Sara Gallardo-Saavedra ◽  
Marcia Eugenio-Gozalbo ◽  
Víctor Alonso-Gómez ◽  
Miguel-Ángel Muñoz-García ◽  
...  
Keyword(s):  
Amorphous Silicon ◽  
Distributed Generation ◽  
Agricultural Sector ◽  
Point Of View ◽  
The Other ◽  
Pv System ◽  
Statistical Point ◽  
Horticultural Crops ◽  
The One ◽  
Solar Resource

For decades, society has been changing towards an energy mix that enhances the use of renewable sources and a more distributed generation of energy. The agricultural sector is included in this trend, which is why several studies are currently being carried out focused on the use of solar energy in greenhouses. This article aims to demonstrate the viability of a greenhouse that integrates, as a novelty, semi-transparent amorphous silicon photovoltaic (PV) glass (a-Si), covering the entire roof surface and the main sides of the greenhouse. The designed prototype is formed by a simple rectangular structure 12 m long and 2.5 m wide, with a monopitch roof, oriented to the southwest, and with a 35° inclination. The greenhouse is divided into two contiguous equal sections, each with an area of 15 m2, and physically separated by an interior partition transparent wall. The surface enclosure of one of the sections is made of conventional glass, and the one of the other, of PV glass. How the presence of semitransparent PV glass influences the growth of horticultural crops has been studied, finding that it slightly reduces the production of vegetal mass and accelerates the apical growth mechanism of heliophilic plants. However, from a statistical point of view, this influence is negligible, so it is concluded that the studied technology is viable for horticultural production. The energy balance carried out indicates that the energy produced by the PV system is greater than the energy consumed by the greenhouse, which shows that the greenhouse is completely viable and self-sufficient for sites with the adequate solar resource.

scholarly journals Microwave single-scattering properties of non-spheroidal raindrops

2020 ◽  
Vol 13 (12) ◽  
pp. 6933-6944
Author(s):  
Robin Ekelund ◽  
Patrick Eriksson ◽  
Michael Kahnert
Keyword(s):  
Remote Sensing ◽  
Microwave Remote Sensing ◽  
Single Scattering ◽  
Large Set ◽  
Brightness Temperatures ◽  
Active Measurements ◽  
Back Scattering ◽  
T Matrix ◽  
Active Microwave Remote Sensing ◽  
The Impact

Abstract. Falling raindrops undergo a change in morphology as they grow in size and the fall speed increases. This change can lead to significant effects in passive and active microwave remote sensing measurements, typically in the form of a polarization signal. Because previous studies generally only considered either passive or active measurements and a limited set of frequencies, there exist no general guidelines on how and when to consider such raindrop effects in scientific and meteorological remote sensing. In an attempt to provide an overview on this topic, this study considered passive and active remote sensing simultaneously and a wider set of frequencies than in previous studies. Single-scattering property (SSP) data of horizontally oriented raindrops were calculated using the T-matrix method at a large set of frequencies (34 in total). The shapes of the raindrops were calculated assuming an aerodynamic equilibrium model, resulting in drops with flattened bases. The SSP data are published in an open-access repository in order to promote the usage of realistic microphysical assumptions in the microwave remote sensing community. Furthermore, the SSPs were employed in radiative transfer simulations of passive and active microwave rain observations, in order to investigate the impact of raindrop shape upon observations and to provide general guidelines on usage of the published database. Several instances of noticeable raindrop shape-induced effects could be identified. For instance, it was found that the flattened base of equilibrium drops can lead to an enhancement in back-scattering at 94.1 GHz of 1.5 dBZ at 10 mm h−1, and passive simulations showed that shape-induced effects on measured brightness temperatures can be at least 1 K.

Some Odyssean Similes

1971 ◽  
Vol 18 (1) ◽  
pp. 81-90
Author(s):  
Anthony J. Podlecki
Keyword(s):  
Point Of View ◽  
The Other ◽  
Statistical Point ◽  
The One ◽  
Point Of Departure

Perhaps the one feature that makes the Iliad and Odyssey most characteristically Homeric—not Virgilian, nor Apollonian—is the similes. They allow Homer to turn from the material at hand for a brief moment to look at some other scene, and the intensity with which he looks at the new scene gives a heightened awareness to the original subject, the thing, person, or event which suggested the simile in the first place and was the simile's point of departure. It is well known that the poet's interest in this new subject occasionally goes beyond the strict needs of the poetic context; he often seems absorbed in and even distracted by the other scene, and so the poetic device to which he has lent his name is frequently understood to mean nothing more than an extended comparison whose development and details are thought to be somehow irrelevant. What I wish to do here is look closely at several of these similes in the Odyssey, not from a statistical point of view or to compare them with those of the Iliad, but rather to consider them as poetic devices which Homer uses in an expert way to achieve just the effect he intends; often, as I hope to show, the subtlety of the effect achieved is surprising.

scholarly journals Representaciones y conductas. Un repertorio de las violencias entre los nahuas de la Sierra Norte de Puebla

Revista Trace ◽  
2018 ◽  
pp. 9 ◽  
Author(s):  
Pierre Beaucage
Keyword(s):  
Domestic Violence ◽  
Daily Life ◽  
The Other ◽  
Large Set ◽  
Multiple Forms ◽  
Other Hand ◽  
Violencia Domestica ◽  
The One ◽  
Culture Of Violence

Entre los nahuas, no hay un equivalente estricto a “violencia”. Sin embargo, la idea de una fuerza excesiva y peligrosa impregna, por una parte, un amplio conjunto de representaciones míticas (violencia fundadora) y ethohistóricas (agresiones y resistencia). También está muy presente en lo cotidiano, en formas múltiples: robos, envidia, brujería y violencia doméstica. A pesar de lo amplio del fenómeno, cuyo corolario es un “discurso de la desgracia”, no se puede hablar aquí de una cultura de la violencia, puesto que nuestros interlocutores dedican mucho esfuerzo a sobrepasarla para construir una felicidad personal y familiar, aunque la sientan muy frágil.Abstract:Among the Nahua, one does not find a strict equivalent to “violence”. Yet, on the one hand, the idea of an excessive, dangerous force permeates a large set of narratives, mythical (founding violence) and ethnohistorical (aggressions and resistance). On the other hand, violence is quite present in daily life, under multiple forms: thefts, “envy” and witchcraft, domestic violence. In spite of this extension, whose corollary is a “discourse of disgrace”, one cannot speak here of a culture of violence, since our interlocutors devote much energy to overcome it in order to build a personal and familial happiness, however frail they may feel it is.Résumé : Chez les Nahuas, il n’y a pas d’équivalent strict à “violence”. Cependant, l’idée d’une force excessive et dangereuse imprègne, d’une part, un vaste ensemble de représentations mythiques (violence fondatrice) et ethnohistoriques (agressions et résistance). Elle est aussi très présente au quotidien, sous de multiples formes : vols, “envie” et sorcellerie, violence domestique. Malgré l’ampleur du phénomène, dont le corollaire est un “discours du malheur”, on ne peut parler ici de culture de la violence, puisque nos interlocuteurs s’attachent à la surmonter pour construire un bonheur personnel et familial, qu’ils sentent cependant fragile.

scholarly journals Microwave single scattering properties of non-spheroidal rain drops

2020 ◽  
Author(s):  
Robin Ekelund ◽  
Patrick Eriksson ◽  
Michael Kahnert
Keyword(s):  
Remote Sensing ◽  
Microwave Remote Sensing ◽  
Single Scattering ◽  
Large Set ◽  
Drop Shape ◽  
Brightness Temperatures ◽  
Rain Drop ◽  
Rain Drops ◽  
Active Microwave Remote Sensing ◽  
The Impact

Abstract. Falling rain drops undergo a change in morphology as they grow in size and the fall-speed increases. This change can lead to significant effects in passive and active microwave remote sensing measurements, typically in the form of a polarization signal. Because previous studies generally only considered either passive or active measurements and a limited set of frequencies, there exist no general guidelines on how and when to consider such rain drop effects in scientific and meteorological remote sensing. In an attempt to provide an overview on this topic, this study considered passive and active remote sensing simultaneously and a wider set of frequencies than in previous studies. Single scattering properties (SSP) data of horizontally oriented rain drops were calculated using the T-matrix method at a large set of frequencies (34 in total). The shapes of the rain drops were calculated assuming an aerodynamic equilibrium model, resulting in drops with flattened bases. The SSP data are published in an open-access repository in order to promote the usage of realistic microphysical assumptions in the microwave remote sensing community. Furthermore, the SSP were employed in radiative transfer simulations of passive and active microwave rain observations, in order to investigate the impact of rain drop shape upon observations and to provide general guidelines on usage of the published database. Several instances of significant rain drop shape-induced effects could be identified. For instance, it was found that the flattened base of equilibrium drops can lead to an enhancement in back-scattering at 94.1 GHz. The passive simulations showed shape induced effects of over 1 K at brightness temperatures below 150 GHz.

Note on Selection of Coordinate Systems for Geodynamics

1975 ◽  
Vol 26 ◽  
pp. 395-407
Author(s):  
S. Henriksen
Keyword(s):  
Sea Level ◽  
The Other ◽  
Coordinate Systems ◽  
Mean Sea Level ◽  
The Earth ◽  
The One ◽  
Static Systems ◽  
Selection Of

The first question to be answered, in seeking coordinate systems for geodynamics, is: what is geodynamics? The answer is, of course, that geodynamics is that part of geophysics which is concerned with movements of the Earth, as opposed to geostatics which is the physics of the stationary Earth. But as far as we know, there is no stationary Earth – epur sic monere. So geodynamics is actually coextensive with geophysics, and coordinate systems suitable for the one should be suitable for the other. At the present time, there are not many coordinate systems, if any, that can be identified with a static Earth. Certainly the only coordinate of aeronomic (atmospheric) interest is the height, and this is usually either as geodynamic height or as pressure. In oceanology, the most important coordinate is depth, and this, like heights in the atmosphere, is expressed as metric depth from mean sea level, as geodynamic depth, or as pressure. Only for the earth do we find “static” systems in use, ana even here there is real question as to whether the systems are dynamic or static. So it would seem that our answer to the question, of what kind, of coordinate systems are we seeking, must be that we are looking for the same systems as are used in geophysics, and these systems are dynamic in nature already – that is, their definition involvestime.

Stories and the Self

2020 ◽  
Vol 32 (2) ◽  
pp. 47-58 ◽  
Author(s):  
Stefan Krause ◽  
Markus Appel
Keyword(s):  
Meta Analysis ◽  
The Self ◽  
The Other ◽  
Lower Degree ◽  
Contrast Effects ◽  
Self Perception ◽  
Self Perceptions ◽  
Other Hand ◽  
The One ◽  
Implicit And Explicit

Abstract. Two experiments examined the influence of stories on recipients’ self-perceptions. Extending prior theory and research, our focus was on assimilation effects (i.e., changes in self-perception in line with a protagonist’s traits) as well as on contrast effects (i.e., changes in self-perception in contrast to a protagonist’s traits). In Experiment 1 ( N = 113), implicit and explicit conscientiousness were assessed after participants read a story about either a diligent or a negligent student. Moderation analyses showed that highly transported participants and participants with lower counterarguing scores assimilate the depicted traits of a story protagonist, as indicated by explicit, self-reported conscientiousness ratings. Participants, who were more critical toward a story (i.e., higher counterarguing) and with a lower degree of transportation, showed contrast effects. In Experiment 2 ( N = 103), we manipulated transportation and counterarguing, but we could not identify an effect on participants’ self-ascribed level of conscientiousness. A mini meta-analysis across both experiments revealed significant positive overall associations between transportation and counterarguing on the one hand and story-consistent self-reported conscientiousness on the other hand.

Radioimmunotherapy for treatment of acute myeloid leukaemia and myelodysplastic syndrome

2005 ◽  
Vol 44 (03) ◽  
pp. 107-117
Author(s):  
R. G. Meyer ◽  
W. Herr ◽  
A. Helisch ◽  
P. Bartenstein ◽  
I. Buchmann
Keyword(s):  
Acute Myeloid Leukaemia ◽  
Myeloid Leukaemia ◽  
Primary Tumour ◽  
The Other ◽  
Haematopoietic Stem Cell ◽  
Other Hand ◽  
Primary Reduction ◽  
The One ◽  
Acute Myeloid

SummaryThe prognosis of patients with acute myeloid leukaemia (AML) has improved considerably by introduction of aggressive consolidation chemotherapy and haematopoietic stem cell transplantation (SCT). Nevertheless, only 20-30% of patients with AML achieve long-term diseasefree survival after SCT. The most common cause of treatment failure is relapse. Additionally, mortality rates are significantly increased by therapy-related causes such as toxicity of chemotherapy and complications of SCT. Including radioimmunotherapies in the treatment of AML and myelodyplastic syndrome (MDS) allows for the achievement of a pronounced antileukaemic effect for the reduction of relapse rates on the one hand. On the other hand, no increase of acute toxicity and later complications should be induced. These effects are important for the primary reduction of tumour cells as well as for the myeloablative conditioning before SCT.This paper provides a systematic and critical review of the currently used radionuclides and immunoconjugates for the treatment of AML and MDS and summarizes the literature on primary tumour cell reductive radioimmunotherapies on the one hand and conditioning radioimmunotherapies before SCT on the other hand.

Das Ende der Postdemokratie, den Pessimismus überwinden.

2017 ◽  
Vol 47 (188) ◽  
pp. 487-494
Author(s):  
Daniel Mullis
Keyword(s):  
Political Thought ◽  
Social Dynamics ◽  
Social Conditions ◽  
The Other ◽  
Economic Decline ◽  
Far Right ◽  
Windows Of Opportunity ◽  
Political Events ◽  
Political Struggles ◽  
The One

In recent years, political and social conditions have changed dramatically. Many analyses help to capture these dynamics. However, they produce political pessimism: on the one hand there is the image of regression and on the other, a direct link is made between socio-economic decline and the rise of the far-right. To counter these aspects, this article argues that current political events are to be understood less as ‘regression’ but rather as a moment of movement and the return of deep political struggles. Referring to Jacques Ranciere’s political thought, the current conditions can be captured as the ‘end of post-democracy’. This approach changes the perspective on current social dynamics in a productive way. It allows for an emphasis on movement and the recognition of the windows of opportunity for emancipatory struggles.

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