GRIPS-HI, a novel spectral imager for ground based measurements of mesopause temperatures

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Johannes Stehr ◽  
Peter Knieling ◽  
Friedhelm Olschewski ◽  
Klaus Mantel ◽  
Martin Kaufmann ◽  
...  
Keyword(s):  
Spectral Resolution ◽  
Global Network ◽  
Vibrationally Excited ◽  
Mesopause Region ◽  
Order Of Magnitude ◽  
Climate Signals ◽  
Mesopause Temperature ◽  
Spectral Imager ◽  
New Generation ◽  
Key Parameter

Abstract The NDMC (Network for the Detection of Mesospheric Change) is a global network of measurement sites dedicated to the surveillance of the mesopause region. One main objective of the network is the early identification of climate signals. A key parameter is the mesopause temperature which can be derived from the emission spectrum of a layer of vibrationally excited hydroxyl (OH) at an altitude of approximately 87 km 87\hspace{0.1667em}\text{km} . Foremost, emission lines in the SWIR regime between 1520 nm 1520\hspace{0.1667em}\text{nm} and 1550 nm 1550\hspace{0.1667em}\text{nm} are of interest for remote temperature sensing. This report deals with the development of a new generation of GRIPS instruments, which are commonly employed for the observation of mesopause temperatures. The new prototype demonstrates how the application of so called Spatial Heterodyne Interferometers (SHI) can overcome the limitations of currently used grating spectrometers, in terms of spectral resolution and optical throughput. The presented prototype proposes improvements in optical throughput and spectral resolution of about one order of magnitude, significantly reducing the uncertainties of the measured mesopause temperatures. Furthermore, an SHI can be built in monolithic configurations which are aligned and characterized once during assembly without the need of realignment at the measurement site. This makes SHI based instruments ideal for mobile applications.

GRIPS-HI - a Novel Interferometer for Measuring Two-Dimensional Temperature Distributions at the Mesopause

2020 ◽  
Author(s):  
Johannes Stehr ◽  
Peter Knieling ◽  
Friedhelm Olschewski ◽  
Martin Kaufmann ◽  
Klaus Mantel ◽  
...  
Keyword(s):  
Global Network ◽  
Two Dimensional ◽  
Mesopause Region ◽  
Band Emission ◽  
Temperature Trends ◽  
Temperature Distributions ◽  
New Instrument ◽  
Order Of Magnitude ◽  
New Type ◽  
Mesopause Temperature

<p>The NDMC (<em>Network for the Detection of Mesopause Change</em>) is a global network of ground based observatories with the objective of monitoring key parameters of the mesopause region. For temperature monitoring GRound-based Infrared P-branch Spectrometers (GRIPS) are widely deployed. These spectrometers allow for the retrieval of the mesopause temperature from the OH* P-band emission lines around 1530 nm. A common technology for GRIPS instruments are spectrometers based on diffraction gratings. To overcome the limitations of conventional grating spectrometers, a new type of spectrometer is being developed within the project <em>Metrology for Earth Observation and Climate - 3</em> (MetEOC-3) which is coordinated by the <em>European Metrology Project for Innovation and Research</em> (EMPIR). The new spectrometer shall improve the quality and traceability of the atmospheric data obtained by the NDMC. It is intended to serve as a reference instrument with significantly smaller measurement uncertainties. It is also designed to identify temperature trends of 1K/decade. A Spatial Heterodyne Interferometer (SHI) was chosen as the most promising technology, offering several advantages. Compared to conventional grating spectrometers, the throughput and resolution of the interferometer is one order of magnitude larger. The use of a two-dimensional detector array in combination with an imaging optics enables the detection of spatial temperature distributions in the mesopause region, as caused by dynamical processes like gravity waves. The talk gives an introduction to the technology of spatial heterodyne interferometry, and the new instrument design and calibration results are presented.</p>

scholarly journals New insights into OH airglow modelling to derive night-time atomic oxygen and atomic hydrogen in the mesopause region

2018 ◽  
Author(s):  
Tilo Fytterer ◽  
Christian von Savigny ◽  
Martin Mlynczak ◽  
Miriam Sinnhuber
Keyword(s):  
Atomic Hydrogen ◽  
Atomic Oxygen ◽  
Box Model ◽  
Satellite Measurements ◽  
Night Time ◽  
Vibrationally Excited ◽  
Mesopause Region ◽  
Airglow Emissions ◽  
Instrument Configuration ◽  
Best Fit

Abstract. An OH airglow model was developed to derive night-time atomic oxygen (O(3P)) and atomic hydrogen (H) from satellite OH airglow observations in the mesopause region (~ 75–100 km). The OH airglow model is based on the zero dimensional box model CAABA/MECCA-3.72f and was empirically adjusted to fit four different OH airglow emissions observed by the satellite/instrument configuration TIMED/SABER at 2.0 μm and at 1.6 μm as well as measurements by ENVISAT/SCIAMACHY of the transitions OH(6-2) and OH(3-1). Comparisons between the Best fit model obtained here and the satellite measurements suggest that deactivation of vibrationally excited OH(v) via OH(v ≥ 7) + O2 might favour relaxation to OH(v' ≤ 5) + O2 by multi-quantum quenching. It is further indicated that the deactivation pathway to OH(v' = v − 5) + O2 dominates. The results also provide general support of the recently proposed mechanism OH(v) + O(3P) → OH(0 ≤ v' ≤ v − 5) + O(1D) but suggest slower rates of OH(v = 7,6,5) + O(3P). Additionally, deactivation to OH(v' = v − 5) + O(1D) might be preferred. The profiles of O(3P) and H derived here are plausible between 80 km and 95  km. The values of O(3P) obtained in this study agree with the corresponding TIMED/SABER values between 80 km and 85 km, but are larger from 85 to 95 km due to different relaxation assumptions of OH(v) + O(3P). The H profile found here is generally larger than TIMED/SABER H by about 30–35 % from 80 to 95 km, which might be attributed to too high O3 night-time values.

Applications of Subseasonal-to-Seasonal Forecasts: Progress and Future Plans

2021 ◽  
Author(s):  
Christopher White ◽  
Joanne Robbins ◽  
Daniela Domeisen ◽  
Andrew Robertson
Keyword(s):  
Real Time ◽  
Disaster Preparedness ◽  
Best Practice ◽  
Focal Point ◽  
Global Network ◽  
Seasonal Forecasts ◽  
Time Data ◽  
Application Development ◽  
User Communities ◽  
New Generation

<p>Subseasonal-to-seasonal (S2S) forecasts are bridging the gap between weather forecasts and long-range predictions. Decisions in various sectors are made in this forecast timescale, therefore there is a strong demand for this new generation of predictions. While much of the focus in recent years has been on improving forecast skill, if S2S predictions are to be used effectively, it is important that along with scientific advances, we also learn how best to develop, communicate and apply these forecasts.</p><p>In this paper, we present recent progress in the applications of S2S forecasts, and provide an overview of ongoing and emerging activities and initiatives from across the wider weather and climate applications and user communities, as follows:</p><ul><li>To support an increased focus on applications, an additional science sub-project focused on S2S applications has been launched on the World Meteorological Organization WWRP-WCRP S2S Prediction Project: http://s2sprediction.net/. This sub-project will provide a focal point for research focused towards S2S applications by exploring the value of applications-relevant S2S forecasts and highlighting the opportunities and challenges facing their uptake.</li> <li>Also supported by the S2S Prediction Project, the ongoing Real-Time Pilot initiative http://s2sprediction.net/file/documents_reports/16Projects.pdf is making S2S forecasts available to 15 selected projects that are addressing user needs over a two year period (November 2019 through to November 2021). By making this real-time data available, the initiative is drawing on the collective experiences of the researcher and user communities from across the projects. The Real-Time Pilot will develop best practice guidelines for producing useful and useable, application-orientated forecasts and tools that can be used to guide future S2S application development. We will present an update on the initiative, including results from an initial set of questionnaires that focussed on engagement strategies and practices, supporting a review of how projects were designs, the roles and responsibilities of different project participants and the methods used to determine project success.</li> <li>To increase the uptake and use of S2S forecasts more widely across the research and user communities, we present a new initiative: a global network of researchers, modellers and practitioners focused on S2S applications, called S2Sapp.net – a community with a shared aim of exploring and promoting cross-sectoral services and applications of this new generation of predictions.</li> <li>Finally, we will provide an update on a recently-submitted applications community review paper, covering sectoral applications of S2S predictions, including public health, disaster preparedness, water management, energy and agriculture. Drawing from the experience of researchers and users working with S2S forecasts, we explore the value of applications-relevant S2S predictions through a series of sectoral cases where uptake is starting to occur.</li> </ul>

Model of Daytime Oxygen Emissions in the Mesopause Region and Above: New Results

2021 ◽  
Author(s):  
Valentine Yankovsky ◽  
Ekaterina Vorobeva ◽  
Rada Manuilova ◽  
Irina Mironova
Keyword(s):  
Molecular Oxygen ◽  
Excited States ◽  
Lower Thermosphere ◽  
Basic Research ◽  
Vibrationally Excited ◽  
Mesopause Region ◽  
Mesosphere And Lower Thermosphere ◽  
Basic Research Grant ◽  
The 19Th Century ◽  
Excited Oxygen

<p>Atmospheric emissions of atomic and molecular oxygen have been observed since the middle of the 19th century. In the last decades, it has been shown that emissions of excited oxygen atom O(<sup>1</sup>D) and molecular oxygen in electronically-vibrationally excited states O<sub>2</sub>(b<sup>1</sup>Σ<sup>+</sup><sub>g</sub>, v) and O<sub>2</sub>(a<sup>1</sup>Δ<sub>g</sub>, v) are related by a unified photochemical mechanism in the mesosphere and lower thermosphere (MLT). The current study is performed in the framework of the state-of-the-art model of ozone and molecular oxygen photodissociation in the daytime MLT. In particular, the study includes a detailed description of the formation mechanism for excited oxygen components in the daytime MLT and presents the comparison of widely used photochemical models. The study also demonstrates new results such as i) new suggestions about possible products of collisional reactions of electronically-vibrationally excited oxygen molecules with atomic oxygen and ii) new estimates of O<sub>2</sub>(b<sup>1</sup>Σ<sup>+</sup><sub>g</sub>, v = 0 – 10) radiative lifetimes which are necessary for solving inverse problems in the lower thermosphere. Moreover, special attention is given to the Barth’s mechanism in order to demonstrate that its contribution to O<sub>2</sub>(b<sup>1</sup>Σ<sup>+</sup><sub>g</sub>, v) and O<sub>2</sub>(a<sup>1</sup>Δ<sub>g</sub>, v) populations is neglectable in daytime conditions regardless of fitting coefficients. In addition, possible applications of the daytime oxygen emissions are presented, e.g., the altitude profiles O(<sup>3</sup>P), O<sub>3</sub> and CO<sub>2</sub> can be retrieved by solving inverse photochemical problems where emissions from electronically vibrationally excited states of O<sub>2</sub> are used as proxies. The funding of V.Y., R.M. and I.M. was partly provided by the Russian Fund for Basic Research (grant RFBR No. 20-05-00450).</p>

scholarly journals Broad-band high-resolution rotational spectroscopy for laboratory astrophysics

2019 ◽  
Vol 626 ◽  
pp. A34 ◽  
Author(s):  
J. Cernicharo ◽  
J. D. Gallego ◽  
J. A. López-Pérez ◽  
F. Tercero ◽  
I. Tanarro ◽  
...  
Keyword(s):  
Spectral Resolution ◽  
Accurate Determination ◽  
Broad Band ◽  
Laboratory Astrophysics ◽  
High Spectral Resolution ◽  
Rotational Spectroscopy ◽  
Rotational Spectrum ◽  
Vibrationally Excited ◽  
Radio Receivers ◽  
Cold Plasmas

We present a new experimental set-up devoted to the study of gas phase molecules and processes using broad-band high spectral resolution rotational spectroscopy. A reactor chamber is equipped with radio receivers similar to those used by radio astronomers to search for molecular emission in space. The whole range of the Q (31.5–50 GHz) and W bands (72–116.5 GHz) is available for rotational spectroscopy observations. The receivers are equipped with 16 × 2.5 GHz fast Fourier transform spectrometers with a spectral resolution of 38.14 kHz allowing the simultaneous observation of the complete Q band and one-third of the W band. The whole W band can be observed in three settings in which the Q band is always observed. Species such as CH3CN, OCS, and SO2 are detected, together with many of their isotopologues and vibrationally excited states, in very short observing times. The system permits automatic overnight observations, and integration times as long as 2.4 × 105 s have been reached. The chamber is equipped with a radiofrequency source to produce cold plasmas, and with four ultraviolet lamps to study photochemical processes. Plasmas of CH4, N2, CH3CN, NH3, O2, and H2, among other species, have been generated and the molecular products easily identified by the rotational spectrum, and via mass spectrometry and optical spectroscopy. Finally, the rotational spectrum of the lowest energy conformer of CH3CH2NHCHO (N-ethylformamide), a molecule previously characterized in microwave rotational spectroscopy, has been measured up to 116.5 GHz, allowing the accurate determination of its rotational and distortion constants and its search in space.

MOTION DETECTION AND DIRECTION DETECTION IN LOCAL NEURAL NETS

1989 ◽  
Vol 01 (02) ◽  
pp. 187-192 ◽  
Author(s):  
H.-U. Bauer ◽  
T. Geisel
Keyword(s):  
Motion Detection ◽  
Pulse Velocity ◽  
Neural Nets ◽  
Global Network ◽  
Training Set ◽  
Backpropagation Algorithm ◽  
Short Term ◽  
Memory Time ◽  
Direction Detection ◽  
Order Of Magnitude

We present a model for motion and direction detection of moving pulses whose performance is independent of pulse velocity, size and shape. The input signal activates one row of instantaneous nodes and one row of time integrating input nodes acting as short-term memories. Motion detection is achieved locally by subnetworks which are trained with a synthetic training set using the backpropagation algorithm. The global network is constructed from these subnetworks, one for each position. We test its performance with different pulse shapes and sizes and find the response to be invariant in a window of pulse velocities an order of magnitude wide. The window can be shifted by adjusting the memory time of the input nodes.

scholarly journals Re-exploring Molecular Complexity with ALMA (ReMoCA): interstellar detection of urea

2019 ◽  
Vol 628 ◽  
pp. A10 ◽  
Author(s):  
A. Belloche ◽  
R. T. Garrod ◽  
H. S. P. Müller ◽  
K. M. Menten ◽  
I. Medvedev ◽  
...  
Keyword(s):  
Column Density ◽  
High Mass ◽  
Synthetic Spectrum ◽  
Mass Star ◽  
Methyl Isocyanate ◽  
Vibrationally Excited ◽  
Data Set ◽  
Star Forming ◽  
Order Of Magnitude ◽  
Molecular Complexity

Context. Urea, NH2C(O)NH2, is a molecule of great importance in organic chemistry and biology. Two searches for urea in the interstellar medium have been reported in the past, but neither were conclusive. Aims. We want to take advantage of the increased sensitivity and angular resolution provided by the Atacama Large Millimeter/submillimeter Array (ALMA) to search for urea toward the hot molecular cores embedded in the high-mass-star-forming region Sgr B2(N). Methods. We used the new spectral line survey named ReMoCA (Re-exploring Molecular Complexity with ALMA) that was performed toward Sgr B2(N) with ALMA in its observing cycle 4 between 84 and 114 GHz. The spectra were analyzed under the local thermodynamic equilibrium approximation. We constructed a full synthetic spectrum that includes all the molecules identified so far. We used new spectroscopic predictions for urea in its vibrational ground state and first vibrationally excited state to search for this complex organic molecule in the ReMoCA data set. We employed the gas-grain chemical kinetics model MAGICKAL to interpret the astronomical observations. Results. We report the secure detection of urea toward the hot core Sgr B2(N1) at a position called N1S slightly offset from the continuum peak, which avoids obscuration by the dust. The identification of urea relies on nine clearly detected transitions. We derive a column density of 2.7 × 1016 cm−2 for urea, two orders of magnitude lower than the column density of formamide, and one order of magnitude below that of methyl isocyanate, acetamide, and N-methylformamide. The latter molecule is reliably identified toward N1S with 60 clearly detected lines, confirming an earlier claim of its tentative interstellar detection. We report the first interstellar detections of NH2CH18O and 15NH2CHO. We also report the nondetection of urea toward the secondary hot core Sgr B2(N2) with an abundance relative to the other four species at least one order of magnitude lower than toward the main hot core. Our chemical model roughly reproduces the relative abundances of formamide, methyl isocyanate, acetamide, and N-methylformamide, but it overproduces urea by at least one order of magnitude. Conclusions. Urea is clearly detected in one of the hot cores. Comparing the full chemical composition of Sgr B2(N1S) and Sgr B2(N2) may help understand why urea is at least one order of magnitude less abundant in the latter source.

Strong enhancement of parity violation effects in chiral uranium compounds

2014 ◽  
Vol 16 (32) ◽  
pp. 17043-17051 ◽  
Author(s):  
Michael Wormit ◽  
Małgorzata Olejniczak ◽  
Anna-Lena Deppenmeier ◽  
Anastasia Borschevsky ◽  
Trond Saue ◽  
...  
Keyword(s):  
Parity Violation ◽  
Strong Enhancement ◽  
Uranium Compounds ◽  
Order Of Magnitude ◽  
New Generation

A new generation of molecular candidates for parity violation measurements. The chiral UNXYZ compounds are predicted to exhibit strong parity violating effects which are up to an order of magnitude larger than for any of the previously suggested candidates.

scholarly journals Sacred Secularities: Ritual and Social Engagement in a Global Buddhist China

Religions ◽  
2018 ◽  
Vol 9 (11) ◽  
pp. 338 ◽  
Author(s):  
Jens Reinke
Keyword(s):  
Social Engagement ◽  
Global Network ◽  
Asian Continent ◽  
Highly Educated ◽  
Ethnographic Fieldwork ◽  
Chinese Migrants ◽  
New Generation ◽  
Social Engagements ◽  
The Relationship ◽  
The Temple

The Taiwanese order Fo Guang Shan is a major representative of renjian Buddhism. The order maintains a global network of over 200 temples and practice centers that spans over not only most of the Asian continent, but also includes Oceania, the Americas, Europe and Africa. This article examines how the order negotiates the modern secular/religious divide by considering the example of its flagship diaspora temple Hsi Lai Temple in L.A., California. Particular attention is given to two prevalent religious practices at the temple—ritual and social engagements—that are often associated with the ‘religious’ and the ‘secular’ respectively. Based on multi-sited ethnographic fieldwork, the article aims to assess the relationship between the two practices and discusses how they resonate with a new generation of highly educated, affluent Chinese migrants.

WHAT YOUR NEXT EXPERIMENT'S DATA WILL LOOK LIKE: EVENT STORES IN THE LARGE HADRON COLLIDER ERA

2005 ◽  
Vol 20 (16) ◽  
pp. 3871-3873 ◽  
Author(s):  
DAVID MALON
Keyword(s):  
Large Hadron Collider ◽  
Hadron Collider ◽  
Simulated Data ◽  
Computing Power ◽  
Atlas Experiment ◽  
Computing Model ◽  
Data Volume ◽  
Order Of Magnitude ◽  
Key Issues ◽  
New Generation

Each new generation of collider experiments confronts the challenge of delivering an event store having at least the performance and functionality of current-generation stores, in the presence of an order of magnitude more data and new computing paradigms (object orientation just a few years ago; grid and service-based computing today). The ATLAS experiment at the Large Hadron Collider, for example, will produce 1.6-megabyte events at 200 Hz–an annual raw data volume of 3.2 petabytes. With derived and simulated data, the total volume may approach 10 petabytes per year. Scale, however, is not the only challenge. In the Large Hadron Collider (LHC) experiments, the preponderance of computing power will come from outside the host laboratory. More significantly, no single site will host a complete copy of the event store–data will be distributed, not simply replicated for convenience, and many physics analyses will routinely require distributed (grid) computing. This paper uses the emerging ATLAS computing model to provide a glimpse of how next-generation event stores are taking shape, touching on key issues in navigation, distribution, scale, coherence, data models and representation, metadata infrastructure, and the role(s) of databases in event store management.

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