Retrieval of chlorine dioxide columns from Sentinel-5p observations

2020 ◽  
Author(s):  
Andreas Carlos Meier ◽  
Andreas Richter ◽  
Gaia Pinardi ◽  
Michel Van Roozendael ◽  
John Philip Burrows
Keyword(s):  
Chlorine Dioxide ◽  
Signal To Noise Ratio ◽  
Stratospheric Ozone ◽  
Polar Vortex ◽  
Current Status ◽  
Innovation Activity ◽  
Signal To Noise ◽  
Fine Spatial Resolution ◽  
Global Coverage ◽  
Good Signal

<p>The Sentinel-5-precursor (S5p) satellite with the TROPOMI payload was launched on 13 October 2017. It is part of the European Copernicus program and provides a set of operational products of atmospheric constituents related to air quality and climate change with almost daily global coverage. The good signal to noise ratio of the instrument enables precise measurements despite the fine spatial resolution of 3.5 x 5.5 km2. </p><p><br>The ESA S5p+ Innovation activity aims at extending the list of S5p products with scientific products, which are not yet part of the operational processor, to exploit the potential of the Sentinel-5p mission’s capabilities beyond its primary objectives. The retrieval of chlorine dioxide (OClO) from S5p is among the seven funded sub projects. Chlorine dioxide is an indicator for chlorine activation in the stratosphere and thus of importance for the understanding of stratospheric ozone chemistry, in particular in the polar vortex. Chlorine dioxide was retrieved from heritage instruments (GOME, SCIAMACHY, GOME2, OMI) and the S5p OClO product will act as a continuation of these time-series.</p><p><br>Here we present the current status of the IUP-Bremen S5p OClO product developed within the ESA S5p+ Innovation framework. The new S5p product will be put into context with products from previous and current (e.g. GOME-2c) satellite missions as well as ground-based measurements used for validation.</p>

Retrieval of chlorine dioxide columns from Sentinel-5p observations

2021 ◽  
Author(s):  
Andreas Carlos Meier ◽  
Andreas Richter ◽  
John P. Burrows ◽  
Gaia Pinardi ◽  
Michel Van Roozendael ◽  
...  
Keyword(s):  
Chlorine Dioxide ◽  
Signal To Noise Ratio ◽  
Stratospheric Ozone ◽  
Polar Vortex ◽  
Current Status ◽  
Innovation Activity ◽  
Fine Spatial Resolution ◽  
Global Coverage ◽  
Good Signal

<p>The Sentinel-5-precursor (S5p) satellite with the TROPOMI payload was launched on 13 October 2017. It is part of the European Copernicus program and provides a set of operational products of atmospheric constituents related to air quality and climate change with almost daily global coverage. The good signal to noise ratio of the instrument enables precise measurements despite the fine spatial resolution of 3.5 x 5.5 km<sup>2</sup>.</p><p>The ESA S5p+ Innovation activity aims at extending the list of S5p products with scientific products, which are not yet part of the operational processor, to exploit the potential of the Sentinel-5p mission’s capabilities beyond its primary objectives. The retrieval of chlorine dioxide (OClO) from S5p is among the seven funded sub projects. Chlorine dioxide is an indicator for chlorine activation in the stratosphere and thus of importance for the understanding of stratospheric ozone chemistry, in particular in the polar vortex. Chlorine dioxide was retrieved from heritage instruments (GOME, SCIAMACHY, GOME2, OMI) and the S5p OClO product will act as a continuation of these time-series.</p><p>Here we present the current status of the IUP-Bremen S5p OClO product developed within the ESA S5p+ Innovation framework. Based on a timeseries longer than 2 years, we demonstrate the good quality of the OClO dataset retrieved from S5p, which shows a high precision (~2.5x10<sup>13</sup> molec/cm<sup>2</sup>) and a small offset (< 5x10<sup>12</sup> molec/cm<sup>2</sup>) compared to heritage products. The comparison to a custom OClO product retrieved from OMI, shows good agreement in magnitude and seasonality, albeit the much larger noise in the OMI dataset. Validation to ground based data from high latitude stations shows excellent agreement.</p>

scholarly journals Observation of tropospheric δ D by IASI over the Western Siberia: comparison with a GCM

2013 ◽  
Vol 6 (6) ◽  
pp. 11055-11092 ◽  
Author(s):  
M. Pommier ◽  
J.-L. Lacour ◽  
C. Risi ◽  
F.-M. Bréon ◽  
C. Clerbaux ◽  
...  
Keyword(s):  
Western Siberia ◽  
Signal To Noise Ratio ◽  
Specific Humidity ◽  
Remote Region ◽  
Satellite Measurements ◽  
Signal To Noise ◽  
Atmospheric Sounding ◽  
Global Coverage ◽  
Observational Errors ◽  
Good Signal

Abstract. This study presents the joint H216O and HDO retrieval from Infrared Atmospheric Sounding Interferometer (IASI) spectra over the Western Siberia. IASI is an instrument on board the MetOp-A European satellite. The global coverage of the instrument and the good signal-to-noise ratio allow us to provide information on δ D over this remote region. We show that IASI measurements may be used to estimate integrated δ D between the surface and 3 km altitude or from 1 to 5 km depending on the thermal contrast, with observational errors lower than 4% and 8%, respectively. The retrieved data are compared to simulations from an isotopic GCM, LMDZ-iso over 2011. The satellite measurements reproduce well the seasonal and day-to-day variations for δ D, showing for the latter a good correlation with the model (r up to 0.8 with the smoothed data in summer). The IASI-based retrievals also show the seasonal variation of the specific humidity in both altitude ranges.

MicroRNA annotation in plants: current status and challenges

2021 ◽  
Author(s):  
Yongxin Zhao ◽  
Zheng Kuang ◽  
Ying Wang ◽  
Lei Li ◽  
Xiaozeng Yang
Keyword(s):  
Small Rna ◽  
Signal To Noise Ratio ◽  
Current Status ◽  
Mirna Biogenesis ◽  
Plant Mirnas ◽  
Signal To Noise ◽  
Advantages And Disadvantages ◽  
Plant Mirna ◽  
History Of ◽  
Mirna Biogenesis Pathway

Abstract Last two decades, the studies on microRNAs (miRNAs) and the numbers of annotated miRNAs in plants and animals have surged. Herein, we reviewed the current progress and challenges of miRNA annotation in plants. Via the comparison of plant and animal miRNAs, we pinpointed out the difficulties on plant miRNA annotation and proposed potential solutions. In terms of recalling the history of methods and criteria in plant miRNA annotation, we detailed how the major progresses made and evolved. By collecting and categorizing bioinformatics tools for plant miRNA annotation, we surveyed their advantages and disadvantages, especially for ones with the principle of mimicking the miRNA biogenesis pathway by parsing deeply sequenced small RNA (sRNA) libraries. In addition, we summarized all available databases hosting plant miRNAs, and posted the potential optimization solutions such as how to increase the signal-to-noise ratio (SNR) in these databases. Finally, we discussed the challenges and perspectives of plant miRNA annotations, and indicated the possibilities offered by an all-in-one tool and platform according to the integration of artificial intelligence.

Estimating Optimum Filter Length in Linear Prediction

1997 ◽  
Vol 51 (5) ◽  
pp. 718-720 ◽  
Author(s):  
O.-P. Sievänen
Keyword(s):  
Raman Spectra ◽  
Prediction Error ◽  
Linear Prediction ◽  
Signal To Noise Ratio ◽  
New Method ◽  
Signal To Noise ◽  
Filter Length ◽  
Optimum Filter ◽  
Good Signal ◽  
Prediction Filter

In this article a new method to estimate optimum filter length in linear prediction is described. Linear prediction was used to enhance resolution of a spectrum. In particular, the dependence of prediction error on filter length has been studied. With calculations of simulated spectra it is shown that the prediction error falls rapidly when the filter length attains its optimum value. This effect is quite pronounced when the spectrum has a good signal-to-noise ratio and the modified covariance method is used to calculate prediction filter coefficients. The method is illustrated with applications to real Raman spectra.

scholarly journals Direct Observations of the Heterogeneity of Supergiant Disks

1977 ◽  
Vol 4 (2) ◽  
pp. 405-405
Author(s):  
J. W. Harvey ◽  
C. R. Lynds ◽  
S. P. Worden
Keyword(s):  
Signal To Noise Ratio ◽  
Atmospheric Dispersion ◽  
Stellar Atmosphere ◽  
High Magnification ◽  
Specific Technique ◽  
Signal To Noise ◽  
Speckle Imaging ◽  
Direct Observations ◽  
Good Signal ◽  
Limb Darkening

Resolved images of the disks of the largest stars observed with the largest telescopes can be constructed using the class of techniques called speckle imaging. The observations must be made with narrow passbands (~ 10 nm), short exposures (~ 20 ms) compensation for atmospheric dispersion, high magnification and good signal-to-noise ratio. One specific technique applied to a Ori (Lynds et al., 1976) shows slight but apparently real differences in the images of the disk corresponding to low and high opacity in the stellar atmosphere which we interpret as due to temperature differences. There are also significant differences in the star’s diameter and/or limb darkening at the two different opacity wavelengths.

scholarly journals A stratospheric prognostic ozone for seamless Earth System Models: performance, impacts and future

2021 ◽  
Author(s):  
Beatriz M. Monge-Sanz ◽  
Alessio Bozzo ◽  
Nicholas Byrne ◽  
Martyn P. Chipperfield ◽  
Michail Diamantakis ◽  
...  
Keyword(s):  
Long Range ◽  
North Atlantic ◽  
Signal To Noise Ratio ◽  
Stratospheric Ozone ◽  
Polar Vortex ◽  
Atlantic Sector ◽  
The North ◽  
Medium Range ◽  
Antarctic Polar Vortex ◽  
The Impact

Abstract. We have implemented a new stratospheric ozone model in the European Centre for Medium-Range Weather Forecasts (ECMWF) system, and tested its performance for different timescales, to assess the impact of stratospheric ozone on meteorological fields. We have used the new ozone model to provide prognostic ozone in medium-range and long-range experiments, showing the feasibility of this ozone scheme for a seamless NWP modelling approach. We find that the stratospheric ozone distribution provided by the new scheme in ECMWF forecast experiments is in very good agreement with observations, even for unusual meteorological conditions such as Arctic stratospheric sudden warmings (SSWs) and Antarctic polar vortex events like the vortex split of year 2002. To assess the impact it has on meteorological variables, we have performed experiments in which the prognostic ozone is interactive with radiation. The new scheme provides a realistic ozone field able to improve the description of the stratosphere in the ECMWF system, we find clear reductions of biases in the stratospheric forecast temperature. The seasonality of the Southern Hemisphere polar vortex is also significantly improved when using the new ozone model. In medium-range simulations we also find improvements in high latitude tropospheric winds during the SSW event considered in this study. In long-range simulations the use of the new ozone model leads to an increase in the winter North Atlantic Oscillation (NAO) index correlation, and an increase in the signal to noise ratio over the North Atlantic sector. In our study we show that by improving the description of the stratospheric ozone in the ECMWF system, the stratosphere-tropospheric coupling improves. This highlights the potential benefits of this new ozone model to exploit stratospheric sources of predictability and improve weather predictions over Europe on a range of time scales.

Spectroscopy with Nonimaging Optics: Application to the Infrared Spectroscopy of Langmuir Monolayers

1992 ◽  
Vol 46 (5) ◽  
pp. 725-731 ◽  
Author(s):  
Joseph T. Buontempo ◽  
Stuart A. Rice
Keyword(s):  
Infrared Spectroscopy ◽  
Crystalline Phase ◽  
Signal To Noise Ratio ◽  
Langmuir Monolayers ◽  
Infrared Light ◽  
Signal To Noise ◽  
Low Intensity ◽  
Nonimaging Optics ◽  
Infrared Reflection ◽  
Good Signal

We discuss the principles of nonimaging optics and demonstrate how nonimaging concentrators can be used to maximize the collection of low-intensity infrared light. Specifically, we show that infrared reflection-absorption spectra can be obtained from a Langmuir monolayer of heneicosanol with a reasonable number of scans. Preliminary results indicate that at 24 Å2/molecule and 6 dyne/cm a heneicosanol monolayer is in a crystalline phase with highly ordered, mostly all- trans molecules, and at 42 Å2/molecule and 0 dyne/cm the monolayer consists of islands of the crystalline phase in coexistence with disordered molecules in a liquid phase. The good signal-to-noise ratio of the spectra obtained demonstrates the important role that nonimaging optics has in spectroscopy, by maximizing light throughput, and we make several suggestions for its implementation in other spectroscopic applications.

Practicalities of Data Collection

2017 ◽  
pp. 77-88
Author(s):  
Riitta Hari ◽  
Aina Puce
Keyword(s):  
Data Collection ◽  
Infection Control ◽  
Signal To Noise Ratio ◽  
Impedance Measurement ◽  
Electrical Safety ◽  
High Signal ◽  
Electrode Impedance ◽  
Signal To Noise ◽  
Skin Preparation ◽  
Good Signal

This chapter provides a number of suggestions about optimization of MEG/EEG recording sessions to guarantee as good signal quality and as high signal-to-noise ratio as possible. It also advices for performing replicability checks on the data. The practical aspects of preparing and performing an EEG recording (skin preparation, electrode-impedance measurement) and postrecording infection control are presented. Similarly, practicalities of performing MEG recordings are discussed. Measurement of MEG sensor-array location with respect to landmarks on the scalp and different methods for the measurement of EEG electrode positions are presented. The chapter ends with a discussion on electrical safety in the MEG/EEG laboratory.

scholarly journals Enrichment of the gynecologic cytologic specimen.

1977 ◽  
Vol 25 (7) ◽  
pp. 504-507 ◽  
Author(s):  
W E Tolles ◽  
G L Garcia
Keyword(s):  
Signal To Noise Ratio ◽  
Enrichment Factors ◽  
Spatial Spectrum ◽  
Current Status ◽  
Differential Analysis ◽  
Signal To Noise ◽  
Principal Objective ◽  
Enrichment Techniques ◽  
Non Destructive ◽  
Destructive Methods

The principal objective of our group has been and continues to be the improvement of the biologic signal-to-noise ratio of the gynecologic cytologic specimen through: the dispersal of clusters and clumps, enrichment of the abnormal component of the dispersed specimen by the method of rate-zonal sedimentation under unit gravity, and monitoring the effects of these manipulations with biophysical non-destructive methods. This report is concerned only with presenting the current status of the effectiveness of our enrichment techniques both qualitatively and quantitatively. Zonal sedimentation creates a broad spatial spectrum of cells by virtue of their different velocities which are directly related to their areas. Certain fractions of this spectrum are extracted, concentrated and deposited on slides for subsequent manual differential analysis, evaluation and documentation. Qualitatively, fractions M1 and M2 show impressive removal of erythrocytes, leukocytes and debris. Quantitatively, enrichment factors vary from 0.1 (depletion) to as high as 26 yielding an average enrichment of about 6, a most rewarding improvement.

The Silicon Pixel Sensors in ATLAS

2001 ◽  
Vol 16 (supp01c) ◽  
pp. 1100-1102 ◽  
Author(s):  
◽  
IGOR GOLELOV
Keyword(s):  
Collection Efficiency ◽  
Signal To Noise Ratio ◽  
Small Cell ◽  
Pixel Detector ◽  
Signal To Noise ◽  
Charge Collection Efficiency ◽  
Atlas Experiment ◽  
Pixel Sensors ◽  
Small Cell Size ◽  
Good Signal

The ATLAS experiment is now in the process of finalizing the development of the design of silicon pixel sensors for use in the pixel detector. The sensors will be operated in a severe LHC radiation enviroment with bias voltages at the end of lifetime up to 600 V while maintaining a good signal-to-noise ratio and charge collection efficiency, small cell size and minimal multiple scattering. The radiation hardness issues and quality assurance procedures are discussed.

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