scholarly journals Retrieval of global upper tropospheric and stratospheric formaldehyde (H<sub>2</sub>CO) distributions from high-resolution MIPAS-Envisat spectra

2008 ◽  
Vol 8 (3) ◽  
pp. 463-470 ◽  
Author(s):  
T. Steck ◽  
N. Glatthor ◽  
T. von Clarmann ◽  
H. Fischer ◽  
J. M. Flaud ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Michelson Interferometer ◽  
Infrared Emission ◽  
Photochemical Reactions ◽  
High Spectral Resolution ◽  
Mean Values ◽  
Upper Troposphere ◽  
Tropical Troposphere ◽  
Noise Error ◽  
The Fourier Transform

Abstract. The Fourier transform spectrometer MIPAS (Michelson Interferometer for Passive Atmospheric Sounding) on Envisat measures infrared emission of the Earth's atmosphere in a limb viewing mode. High spectral resolution measurements of MIPAS are sensitive to formaldehyde from the upper troposphere to the stratopause. Single profile retrievals of formaldehyde are dominated by a 60% noise error; however zonal mean values for 30 days of data during 8 September 2003 and 1 December 2003 reduces this error by a factor of 20 or more. The number of degrees of freedom for single profile retrieval ranges from 2 to 4.5 depending on latitude and number of cloud-free tangent altitudes. In the upper tropical troposphere zonal mean values of about 70 parts per trillion by volume (pptv) were found, which have been attributed to biomass burning emissions. In the stratosphere, formaldehyde values are determined by photochemical reactions. In the upper tropical stratosphere, formaldehyde zonal mean maximum values can reach 130 pptv. Diurnal variations in this region can be up to 50 pptv. Comparisons with other satellite instruments show generally good agreement in the region of upper troposphere and lower stratosphere as well as in the upper stratosphere.

scholarly journals Retrieval of global upper tropospheric and stratospheric formaldehyde (H<sub>2</sub>CO) distributions from high-resolution MIPAS-Envisat spectra

2007 ◽  
Vol 7 (5) ◽  
pp. 13627-13652 ◽  
Author(s):  
T. Steck ◽  
N. Glatthor ◽  
T. von Clarmann ◽  
H. Fischer ◽  
J. M. Flaud ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Michelson Interferometer ◽  
Infrared Emission ◽  
Photochemical Reactions ◽  
High Spectral Resolution ◽  
Mean Values ◽  
Upper Troposphere ◽  
Tropical Troposphere ◽  
Noise Error ◽  
The Fourier Transform

Abstract. The Fourier transform spectrometer MIPAS (Michelson Interferometer for Passive Atmospheric Sounding) on Envisat measures infrared emission of the Earth's atmosphere in a limb viewing mode. High spectral resolution measurements of MIPAS are sensitive to formaldehyde from the upper troposphere to the stratopause. Formaldehyde single profile retrieval is formally possible, however with a large noise error (more than 60%), which is the dominant error source. The number of degrees of freedom for single profile retrieval ranges from 2 to 4.5 depending on latitude and number of cloud-free tangent altitudes. Calculation of zonal mean values for 30 days of data during 8 September 2003 and 1 December 2003 reduces the noise induced error by a factor of 20 or more. In the upper tropical troposphere zonal mean values of about 70 parts per trillion by volume (pptv) were found, which have been attributed to biomass burning emissions. In the stratosphere, formaldehyde values are determined by photochemical reactions. In the upper tropical stratosphere, formaldehyde zonal mean maximum values can reach 130 pptv. Diurnal variations in this region can be up to 50 pptv. Comparisons with other satellite instruments show generally good agreement in the region of upper troposphere and lower stratosphere as well as in the upper stratosphere.

scholarly journals MIPAS detection of cloud and aerosol particle occurrence in the UTLS with comparison to HIRDLS and CALIOP

2012 ◽  
Vol 5 (10) ◽  
pp. 2537-2553 ◽  
Author(s):  
H. Sembhi ◽  
J. Remedios ◽  
T. Trent ◽  
D. P. Moore ◽  
R. Spang ◽  
...  
Keyword(s):  
Aerosol Particle ◽  
Detection System ◽  
Michelson Interferometer ◽  
Detection Limits ◽  
Infrared Emission ◽  
High Spectral Resolution ◽  
Radiative Transfer Model ◽  
Transfer Model ◽  
Polar Regions ◽  
Particle Injection

Abstract. Satellite infrared emission instruments require efficient systems that can separate and flag observations which are affected by clouds and aerosols. This paper investigates the identification of cloud and aerosols from infrared, limb sounding spectra that were recorded by the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS), a high spectral resolution Fourier transform spectrometer on the European Space Agency's (ESA) ENVISAT (Now inoperative since April 2012 due to loss of contact). Specifically, the performance of an existing cloud and aerosol particle detection method is simulated with a radiative transfer model in order to establish, for the first time, confident detection limits for particle presence in the atmosphere from MIPAS data. The newly established thresholds improve confidence in the ability to detect particle injection events, plume transport in the upper troposphere and lower stratosphere (UTLS) and better characterise cloud distributions utilising MIPAS spectra. The method also provides a fast front-end detection system for the MIPClouds processor; a processor designed for the retrieval of macro- and microphysical cloud properties from the MIPAS data. It is shown that across much of the stratosphere, the threshold for the standard cloud index in band A is 5.0 although threshold values of over 6.0 occur in restricted regimes. Polar regions show a surprising degree of uncertainty at altitudes above 20 km, potentially due to changing stratospheric trace gas concentrations in polar vortex conditions and poor signal-to-noise due to cold atmospheric temperatures. The optimised thresholds of this study can be used for much of the time, but time/composition-dependent thresholds are recommended for MIPAS data for the strongly perturbed polar stratosphere. In the UT, a threshold of 5.0 applies at 12 km and above but decreases rapidly at lower altitudes. The new thresholds are shown to allow much more sensitive detection of particle distributions in the UTLS, with extinction detection limits above 13 km often better than 10−4 km−1, with values approaching 10−5 km−1 in some cases. Comparisons of the new MIPAS results with cloud data from HIRDLS and CALIOP, outside of the poles, establish a good agreement in distributions (cloud and aerosol top heights and occurrence frequencies) with an offset between MIPAS and the other instruments of 0.5 km to 1 km between 12 km and 20 km, consistent with vertical oversampling of extended cloud layers within the MIPAS field of view. We conclude that infrared limb sounders provide a very consistent picture of particles in the UTLS, allowing detection limits which are consistent with the lidar observations. Investigations of MIPAS data for the Mount Kasatochi volcanic eruption on the Aleutian Islands and the Black Saturday fires in Australia are used to exemplify how useful MIPAS limb sounding data were for monitoring aerosol injections into the UTLS. It is shown that the new thresholds allowed such events to be much more effectively derived from MIPAS with detection limits for these case studies of 1 × 10−5 km−1 at a wavelength of 12 μm.

scholarly journals Infrared limb emission measurements of aerosol in the troposphere and stratosphere

2016 ◽  
Vol 9 (9) ◽  
pp. 4399-4423 ◽  
Author(s):  
Sabine Griessbach ◽  
Lars Hoffmann ◽  
Reinhold Spang ◽  
Marc von Hobe ◽  
Rolf Müller ◽  
...  
Keyword(s):  
Volcanic Ash ◽  
Lower Stratosphere ◽  
Michelson Interferometer ◽  
Emission Spectra ◽  
High Spectral Resolution ◽  
Volcanic Aerosol ◽  
Atmospheric Infrared Sounder ◽  
Ice Clouds ◽  
Upper Troposphere ◽  
Atmospheric Sounding

Abstract. Altitude-resolved aerosol detection in the upper troposphere and lower stratosphere (UTLS) is a challenging task for remote sensing instruments. Infrared limb emission measurements provide vertically resolved global measurements at day- and nighttime in the UTLS. For high-spectral-resolution infrared limb instruments we present here a new method to detect aerosol and separate between ice and non-ice particles. The method is based on an improved aerosol–cloud index that identifies infrared limb emission spectra affected by non-ice aerosol or ice clouds. For the discrimination between non-ice aerosol and ice clouds we employed brightness temperature difference correlations. The discrimination thresholds for this method were derived from radiative transfer simulations (including scattering) and Michelson Interferometer for Passive Atmospheric Sounding (MIPAS)/Envisat measurements obtained in 2011. We demonstrate the value of this approach for observations of volcanic ash and sulfate aerosol originating from the Grímsvötn (Iceland, 64° N), Puyehue–Cordón Caulle (Chile, 40° S), and Nabro (Eritrea, 13° N) eruptions in May and June 2011 by comparing the MIPAS volcanic aerosol detections with Atmospheric Infrared Sounder (AIRS) volcanic ash and SO2 measurements.

scholarly journals Spin-Orbit Entanglement in Time Evolution of Radial Wave Packets in Hydrogenic Systems

2004 ◽  
Vol 11 (04) ◽  
pp. 401-409
Author(s):  
Marcin Turek ◽  
Piotr Rozmej
Keyword(s):  
Wave Packet ◽  
Time Evolution ◽  
Time Scale ◽  
Degrees Of Freedom ◽  
Wave Packets ◽  
Characteristic Time Scale ◽  
Radial Wave ◽  
Mean Values ◽  
Breathing Motion ◽  
Wave Packet Revival

Time evolution of radial wave packets built from the eigenstates of Dirac equation for a hydrogenic system is considered. Radial wave packets are constructed from the states of different n quantum numbers and the same lowest angular momentum. In general they exhibit a kind of breathing motion with dispersion and (partial) revivals. Calculations show that for some particular preparations of the wave packet one can observe interesting effects in spin motion, coming from inherent entanglement of spin and orbital degrees of freedom. These effects manifest themselves through some oscillations in the mean values of spin operators and through changes of spatial probability density carried by upper and lower components of the wave function. It is also shown that the characteristic time scale of predicted effects (called T ls ) is much smaller for radial wave packets than in other cases, reaching values comparable to (or even less than) the time scale for the wave packet revival.

scholarly journals A non-iterative linear retrieval for infrared high-resolution limb sounders

2013 ◽  
Vol 6 (5) ◽  
pp. 1381-1396
Author(s):  
L. Millán ◽  
A. Dudhia
Keyword(s):  
High Resolution ◽  
Computing Time ◽  
Michelson Interferometer ◽  
High Spectral Resolution ◽  
Radiative Transfer Model ◽  
Spectral Signature ◽  
Transfer Model ◽  
Concentration Difference ◽  
Error Margin ◽  
Retrieval Scheme

Abstract. Currently, most of the high-spectral-resolution infrared limb sounders use subsets of the recorded spectra (microwindows) in their retrieval schemes to reduce the computing time of rerunning the radiative transfer model. A fast linear retrieval scheme is described which allows the whole spectral signature of the target molecule to be used. We determine that pressure and temperature retrievals can be treated linearly up to a 20% difference between the atmospheric state and the linearisation point for a 3% error margin and up to 10 K "difference" for a 3 K error margin near the stratopause and less than 0.5 K elsewhere. Assuming perfect pT knowledge, CH4 retrievals can be be treated linearly up to a 20% CH4 concentration "difference" for a 2% error margin. As an example, this technique is implemented for the Michelson Interferometer for Passive Atmospheric Sounding instrument, but it is applicable to any high-resolution limb sounder.

Polarized high-spectral-resolution lidar based on field-widened Michelson interferometer

2016 ◽  
Author(s):  
Dong Liu ◽  
Zhongtao Cheng ◽  
Jing Luo ◽  
Yongying Yang ◽  
Yupeng Zhang ◽  
...  
Keyword(s):  
Spectral Resolution ◽  
Michelson Interferometer ◽  
High Spectral Resolution ◽  
High Spectral Resolution Lidar

The infrared spectrum of CS

1984 ◽  
Vol 62 (12) ◽  
pp. 1414-1419 ◽  
Author(s):  
R. J. Winkel Jr. ◽  
Sumner P. Davis ◽  
Rubén Pecyner ◽  
James W. Brault
Keyword(s):  
Fourier Transform ◽  
Infrared Emission ◽  
Solar Observatory ◽  
Band Head ◽  
The Other ◽  
Fourier Transform Spectrometer ◽  
National Solar Observatory ◽  
Carbon Monosulfide ◽  
Vibration Rotation ◽  
The Fourier Transform

The infrared emission spectrum of carbon monosulfide was observed as a sequence of vibration–rotation bands in the X1Σ+ state, with strong heads of the Δν = 2 sequence degraded to the red. Eight bands of 12C32S were identified, and bands corresponding to the isotope 12C34S were also observed. The most prominent band head, that of the (2–0) band, is at 2585 cm−1, with the other heads spaced approximately 26 cm−1 to smaller wavenumbers. Our data, taken with the Fourier transform spectrometer at the National Solar Observatory (Kitt Peak) include the first reported laboratory observations of the band heads and as many as 200 lines in each band. These observations allowed the calculation of vibrational and rotational constants to higher order than previously reported.

scholarly journals Bias determination and precision validation of ozone profiles from MIPAS-Envisat retrieved with the IMK-IAA processor

2007 ◽  
Vol 7 (13) ◽  
pp. 3639-3662 ◽  
Author(s):  
T. Steck ◽  
T. von Clarmann ◽  
H. Fischer ◽  
B. Funke ◽  
N. Glatthor ◽  
...  
Keyword(s):  
Stratospheric Ozone ◽  
Michelson Interferometer ◽  
High Spectral Resolution ◽  
Vapor Concentration ◽  
Atmospheric Sounding ◽  
Mean Differences ◽  
Microwave Radiometers ◽  
Vertical Ozone ◽  
Vertical Ozone Profiles ◽  
Polar Ozone

Abstract. This paper characterizes vertical ozone profiles retrieved with the IMK-IAA (Institute for Meteorology and Climate Research, Karlsruhe – Instituto de Astrofisica de Andalucia) science-oriented processor from high spectral resolution data (until March 2004) measured by the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) aboard the environmental satellite Envisat. Bias determination and precision validation is performed on the basis of correlative measurements by ground-based lidars, Fourier transform infrared spectrometers, and microwave radiometers as well as balloon-borne ozonesondes, the balloon-borne version of MIPAS, and two satellite instruments (Halogen Occultation Experiment and Polar Ozone and Aerosol Measurement III). Percentage mean differences between MIPAS and the comparison instruments for stratospheric ozone are generally within ±10%. The precision in this altitude region is estimated at values between 5 and 10% which gives an accuracy of 15 to 20%. Below 18 km, the spread of the percentage mean differences is larger and the precision degrades to values of more than 20% depending on altitude and latitude. The main reason for the degraded precision at low altitudes is attributed to undetected thin clouds which affect MIPAS retrievals, and to the influence of uncertainties in the water vapor concentration.

Gas Turbine Exhaust Emissions Monitoring Using Nonintrusive Infrared Spectroscopy

1998 ◽  
Vol 120 (3) ◽  
pp. 514-518 ◽  
Author(s):  
M. Hilton ◽  
A. H. Lettington ◽  
C. W. Wilson
Keyword(s):  
Gas Turbine ◽  
Molecular Species ◽  
Tomographic Reconstruction ◽  
Emission Spectra ◽  
Exhaust Emissions ◽  
Infrared Emission ◽  
High Spectral Resolution ◽  
Rotational Line ◽  
Spectroscopic Techniques ◽  
Reconstruction Procedure

Infrared (IR) spectra of the exhaust emissions from a static gas turbine engine have been studied using Fourier Transform (FT) spectroscopic techniques. Passive detection of the infrared emission from remote (range ∼ 3 m) hot exhaust gases was obtained nonintrusively using a high spectral resolution (0.25 cm−1) FTIR spectrometer. Remote gas temperatures were determined from their emission spectra using the total radiant flux method or by analysis of rotational line structure. The HITRAN database of atmospheric species was used to model the emission from gas mixtures at the relevant temperatures. The spatial distribution of molecular species across a section transverse to the exhaust plume ∼10 cm downstream of the jet pipe nozzle was studied using a tomographic reconstruction procedure. Spectra of the infrared emission from the plume were taken along a number of transverse lines of sight from the centerline of the engine outwards. A mathematical matrix inversion technique was applied to reconstruct the molecular concentrations of CO and CO2 in concentric regions about the centerline. Quantitative measurement of the molecular species concentrations determined nonintrusively were compared with results from conventional extractive sampling techniques.

Balloon-borne GLORIA hyperspectral Limb and Nadir imager in the LWIR

2021 ◽  
Author(s):  
Erik Kretschmer ◽  
Felix Friedl-Vallon ◽  
Thomas Gulde ◽  
Michael Höpfner ◽  
Sören Johansson ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Optical System ◽  
Late Summer ◽  
High Spectral Resolution ◽  
Fourier Transform Spectrometer ◽  
System Improvement ◽  
The Fourier Transform ◽  
Temperature Retrieval ◽  
Long Wave Infrared ◽  
Better Than

&lt;p&gt;The GLORIA-B (Gimballed Limb Observer for Radiance Imaging of the Atmosphere - Balloon) instrument is an adaptation of the very successful GLORIA-AB imaging Fourier transform spectrometer (iFTS) flown on the research aircrafts HALO and M55 Geophysica. The high spectral resolution in the LWIR (Long Wave Infrared) allows for the retrieval of temperature and of a broad range of atmospheric trace gases, with the goal to retrieve O&lt;sub&gt;3&lt;/sub&gt;, H&lt;sub&gt;2&lt;/sub&gt;O, HNO&lt;sub&gt;3&lt;/sub&gt;, C&lt;sub&gt;2&lt;/sub&gt;H&lt;sub&gt;6&lt;/sub&gt;, C&lt;sub&gt;2&lt;/sub&gt;H&lt;sub&gt;2&lt;/sub&gt;, HCOOH, CCl&lt;sub&gt;4&lt;/sub&gt;, PAN, ClONO&lt;sub&gt;2&lt;/sub&gt;, CFC-11, CFC-12, SF&lt;sub&gt;6&lt;/sub&gt;, OCS, NH&lt;sub&gt;3&lt;/sub&gt;, HCN, BrONO&lt;sub&gt;2&lt;/sub&gt;, HO&lt;sub&gt;2&lt;/sub&gt;NO&lt;sub&gt;2&lt;/sub&gt;, N&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;5&lt;/sub&gt; and NO&lt;sub&gt;2&lt;/sub&gt;. The radiometric sensitivity of the Balloon instrument is further increased in comparison with the GLORIA-AB instrument by having two detector channels on the same focal plane array, while keeping the same concept of a cooled optical system. This system improvement was achieved with minimal adaptation of the existing optical system.&lt;/p&gt;&lt;p&gt;The high spatial and temporal resolution of the instrument is ensured by the imaging capability of the Fourier transform spectrometer while stabilizing the line-of-sight in elevation with the instrument and in azimuth with the balloon gondola. In a single measurement lasting 13 seconds, the atmosphere can be sounded from mid-troposphere up to flight altitude, typically 30 km, with a vertical resolution always better than 1 km for most retrieved species; a spatial resolution up to 0.3 km can be achieved in favourable conditions. Temperature retrieval precision between 0.1 and 0.2 K is expected. A spectral sampling up to 0.0625 cm&lt;sup&gt;-1&lt;/sup&gt; can be achieved.&lt;/p&gt;&lt;p&gt;The first flight of GLORIA-B shall take place during the late-summer polar jet turn-around at Kiruna/ESRANGE. This flight is organised in the frame of the HEMERA project and was scheduled for summer 2020, but was ultimately postponed to summer 2021. Beyond qualification of the first balloon-borne iFTS, the scientific goals of the flight are, among others, the quantification of the stratospheric bromine budget and its diurnal evolution by measuring vertical profiles of BrONO&lt;sub&gt;2 &lt;/sub&gt;in combination with BrO observations by the DOAS instrument of University Heidelberg on the same platform.&lt;/p&gt;

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