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Article ; Online: Combined direct-sun ultraviolet and infrared spectroscopies at Popocatépetl volcano (Mexico)

N. Taquet / C. Rivera Cárdenas / W. Stremme / T. Boulesteix / A. Bezanilla / M. Grutter / O. García / F. Hase / T. Blumenstock

Frontiers in Earth Science, Vol

2023 Volume 11

Abstract: Volcanic plume composition is strongly influenced by both changes in magmatic systems and plume-atmosphere interactions. Understanding the degassing mechanisms controlling the type of volcanic activity implies deciphering the contributions of magmatic ... ...

Abstract	Volcanic plume composition is strongly influenced by both changes in magmatic systems and plume-atmosphere interactions. Understanding the degassing mechanisms controlling the type of volcanic activity implies deciphering the contributions of magmatic gases reaching the surface and their posterior chemical transformations in contact with the atmosphere. Remote sensing techniques based on direct solar absorption spectroscopy provide valuable information about most of the emitted magmatic gases but also on gas species formed and converted within the plumes. In this study, we explore the procedures, performances and benefits of combining two direct solar absorption techniques, high resolution Fourier Transform Infrared Spectroscopy (FTIR) and Ultraviolet Differential Optical Absorption Spectroscopy (UV-DOAS), to observe the composition changes in the Popocatépetl’s plume with high temporal resolution. The SO2 vertical columns obtained from three instruments (DOAS, high resolution FTIR and Pandora) were found similar (median difference <12%) after their intercalibration. We combined them to determine with high temporal resolution the different hydrogen halide and halogen species to sulfur ratios (HF/SO2, BrO/SO2, HCl/SO2, SiF4/SO2, detection limit of HBr/SO2) and HCl/BrO in the Popocatépetl’s plume over a 2.5-years period (2017 to mid-2019). BrO/SO2, BrO/HCl, and HCl/SO2 ratios were found in the range of (0.63 ± 0.06 to 1.14 ± 0.20) × 10−4, (2.6 ± 0.5 to 6.9 ± 2.6) × 10−4, and 0.08 ± 0.01 to 0.21 ± 0.01 respectively, while the SiF4/SO2 and HF/SO2 ratios were found fairly constant at (1.56 ± 0.25) × 10−3 and 0.049 ± 0.001. We especially focused on the full growth/destruction cycle of the most voluminous lava dome of the period that took place between February and April 2019. A decrease of the HCl/SO2 ratio was observed with the decrease of the extrusive activity. Furthermore, the short-term variability of BrO/SO2 is measured for the first time at Popocatépetl volcano together with HCl/SO2, revealing different ...
Keywords	solar absorption spectroscopy ; volcanic degassing ; Popocatépetl ; FTIR ; DOAS ; Pandora ; Science ; Q
Subject code	500
Language	English
Publishing date	2023-04-01T00:00:00Z
Publisher	Frontiers Media S.A.
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Anthropogenic CO 2 emission estimates in the Tokyo metropolitan area from ground-based CO 2 column observations

H. Ohyama / M. M. Frey / I. Morino / K. Shiomi / M. Nishihashi / T. Miyauchi / H. Yamada / M. Saito / M. Wakasa / T. Blumenstock / F. Hase

Atmospheric Chemistry and Physics, Vol 23, Pp 15097-

2023 Volume 15119

Abstract: Urban areas are responsible for more than 40 % of global energy-related carbon dioxide (CO 2 ) emissions. The Tokyo metropolitan area (TMA), Japan, one of the most populated regions in the world, includes various emission sources, such as thermal power ... ...

Abstract	Urban areas are responsible for more than 40 % of global energy-related carbon dioxide (CO 2 ) emissions. The Tokyo metropolitan area (TMA), Japan, one of the most populated regions in the world, includes various emission sources, such as thermal power plants, automobile traffic, and residential facilities. In order to infer a top–down emission estimate, we conducted an intensive field campaign in the TMA from February to April 2016 to measure column-averaged dry-air mole fractions of CO 2 (XCO 2 ) with three ground-based Fourier transform spectrometers (one IFS 125HR and two EM27/SUN spectrometers). At two urban sites (Saitama and Sodegaura), measured XCO 2 values were generally larger than those at a rural site (Tsukuba) by up to 9.5 ppm, and average diurnal variations increased toward evening. To simulate the XCO 2 enhancement ( Δ XCO 2 ) resulting from emissions at each observation site, we used the Stochastic Time-Inverted Lagrangian Transport (STILT) model driven by meteorological fields at a horizontal resolution of ∼1 km from the Weather Research and Forecasting (WRF) model, which was coupled with anthropogenic (large point source and area source) CO 2 emissions and biogenic fluxes. Although some of the diurnal variation of Δ XCO 2 was not reproduced and plumes from nearby large point sources were not captured, primarily because of a transport modeling error, the WRF–STILT simulations using prior fluxes were generally in good agreement with the observations (mean bias, 0.30 ppm; standard deviation, 1.31 ppm). By combining observations with high-resolution modeling, we developed an urban-scale inversion system in which spatially resolved CO 2 emission fluxes at >3 km resolution and a scaling factor of large point source emissions were estimated on a monthly basis by using Bayesian inference. The XCO 2 simulation results from the posterior CO 2 fluxes were improved (mean bias, −0.03 ppm; standard deviation, 1.21 ppm). The prior and posterior total CO 2 emissions in the TMA are 1.026 ± 0.116 and 1.037 ± ...
Keywords	Physics ; QC1-999 ; Chemistry ; QD1-999
Subject code	511
Language	English
Publishing date	2023-12-01T00:00:00Z
Publisher	Copernicus Publications
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Weekly derived top-down volatile-organic-compound fluxes over Europe from TROPOMI HCHO data from 2018 to 2021

G.-M. Oomen / J.-F. Müller / T. Stavrakou / I. De Smedt / T. Blumenstock / R. Kivi / M. Makarova / M. Palm / A. Röhling / Y. Té / C. Vigouroux / M. M. Friedrich / U. Frieß / F. Hendrick / A. Merlaud / A. Piters / A. Richter / M. Van Roozendael / T. Wagner

Atmospheric Chemistry and Physics, Vol 24, Pp 449-

2024 Volume 474

Abstract: Volatile organic compounds (VOCs) are key precursors of particulate matter and tropospheric ozone. Although the terrestrial biosphere is by far the largest source of VOCs into the atmosphere, the emissions of biogenic VOCs remain poorly constrained at ... ...

Abstract	Volatile organic compounds (VOCs) are key precursors of particulate matter and tropospheric ozone. Although the terrestrial biosphere is by far the largest source of VOCs into the atmosphere, the emissions of biogenic VOCs remain poorly constrained at the regional scale. In this work, we derive top-down biogenic emissions over Europe using weekly averaged TROPOMI formaldehyde (HCHO) data from 2018 to 2021. The systematic bias of the TROPOMI HCHO columns is characterized and corrected for based on comparisons with FTIR data at seven European stations. The top-down fluxes of biogenic, pyrogenic, and anthropogenic VOC sources are optimized using an inversion framework based on the MAGRITTEv1.1 chemistry transport model and its adjoint. The inversion leads to strongly increased isoprene emissions with respect to the MEGAN–MOHYCAN inventory over the model domain (from 8.1 to 18.5 Tg yr −1 ), which is driven by the high observed TROPOMI HCHO columns in southern Europe. The impact of the inversion on biomass burning VOCs ( + 13 %) and anthropogenic VOCs ( − 17 %) is moderate. An evaluation of the optimized HCHO distribution against ground-based remote sensing (FTIR and MAX-DOAS) and in situ data provides generally improved agreement at stations below about 50 ∘ N but indicates overestimated emissions in northern Scandinavia. Sensitivity inversions show that the top-down emissions are robust with respect to changes in the inversion settings and in the model chemical mechanism, leading to differences of up to 10 % in the total emissions. However, the top-down emissions are very sensitive to the bias correction of the observed columns, as the biogenic emissions are 3 times lower when the correction is not applied. Furthermore, the use of different a priori biogenic emissions has a significant impact on the inversion results due to large differences among bottom-up inventories. The sensitivity run using CAMS-GLOB-BIOv3.1 as a priori emissions in the inversion results in 30 % lower emissions with respect to the optimization ...
Keywords	Physics ; QC1-999 ; Chemistry ; QD1-999
Subject code	550
Language	English
Publishing date	2024-01-01T00:00:00Z
Publisher	Copernicus Publications
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Measurement report

B. Herrera / A. Bezanilla / T. Blumenstock / E. Dammers / F. Hase / L. Clarisse / A. Magaldi / C. Rivera / W. Stremme / K. Strong / C. Viatte / M. Van Damme / M. Grutter

Atmospheric Chemistry and Physics, Vol 22, Pp 14119-

Evolution and distribution of NH 3 over Mexico City from ground-based and satellite infrared spectroscopic measurements

2022 Volume 14132

Abstract: Ammonia (NH 3 ) is the most abundant alkaline compound in the atmosphere, with consequences for the environment, human health, and radiative forcing. In urban environments, it is known to play a key role in the formation of secondary aerosols through its ...

Abstract	Ammonia (NH 3 ) is the most abundant alkaline compound in the atmosphere, with consequences for the environment, human health, and radiative forcing. In urban environments, it is known to play a key role in the formation of secondary aerosols through its reactions with nitric and sulfuric acids. However, there are only a few studies about NH 3 in Mexico City. In this work, atmospheric NH 3 was measured over Mexico City between 2012 and 2020 by means of ground-based solar absorption spectroscopy using Fourier transform infrared (FTIR) spectrometers at two sites (urban and remote). Total columns of NH 3 were retrieved from the FTIR spectra and compared with data obtained from the Infrared Atmospheric Sounding Interferometer (IASI) satellite instrument. The diurnal variability of NH 3 differs between the two FTIR stations and is strongly influenced by the urban sources. Most of the NH 3 measured at the urban station is from local sources, while the NH 3 observed at the remote site is most likely transported from the city and surrounding areas. The evolution of the boundary layer and the temperature play a significant role in the recorded seasonal and diurnal patterns of NH 3 . Although the vertical columns of NH 3 are much larger at the urban station, the observed annual cycles are similar for both stations, with the largest values in the warm months, such as April and May. The IASI measurements underestimate the FTIR NH 3 total columns by an average of 32.2±27.5 % but exhibit similar temporal variability. The NH 3 spatial distribution from IASI shows the largest columns in the northeast part of the city. In general, NH 3 total columns over Mexico City measured at the FTIR stations exhibited an average annual increase of <math xmlns="http://www.w3.org/1998/Math/MathML" id="M16" display="inline" overflow="scroll" dspmath="mathml"><mrow><mn mathvariant="normal">92</mn><mo>±</mo><mn mathvariant="normal">3.9</mn><mo>×</mo><msup><mn ...<br />
Keywords	Physics ; QC1-999 ; Chemistry ; QD1-999
Subject code	511 ; 333
Language	English
Publishing date	2022-11-01T00:00:00Z
Publisher	Copernicus Publications
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Quantifying CH 4 emissions in hard coal mines from TROPOMI and IASI observations using the wind-assigned anomaly method

Q. Tu / M. Schneider / F. Hase / F. Khosrawi / B. Ertl / J. Necki / D. Dubravica / C. J. Diekmann / T. Blumenstock / D. Fang

Atmospheric Chemistry and Physics, Vol 22, Pp 9747-

2022 Volume 9765

Abstract: Intensive coal mining activities in the Upper Silesian Coal Basin (USCB) in southern Poland are resulting in large amounts of methane ( CH 4 ) emissions. Annual CH 4 emissions reached 448 kt according to the European Pollutant Release and Transfer ... ...

Abstract	Intensive coal mining activities in the Upper Silesian Coal Basin (USCB) in southern Poland are resulting in large amounts of methane ( CH 4 ) emissions. Annual CH 4 emissions reached 448 kt according to the European Pollutant Release and Transfer Register (E-PRTR, 2017). As a CH 4 emission hotspot in Europe, it is of importance to investigate its emission sources and make accurate emission estimates. In this study, we use satellite-based total column-averaged dry-air mole fraction of CH 4 ( XCH 4 ) from the TROPOspheric Monitoring Instrument (TROPOMI) and tropospheric XCH 4 ( TXCH 4 ) from the Infrared Atmospheric Sounding Interferometer (IASI). In addition, the high-resolution model forecasts, XCH 4 and TXCH 4 , from the Copernicus Atmosphere Monitoring Service (CAMS) are used to estimate the CH 4 emission rate averaged over 3 years (November 2017–December 2020) in the USCB region (49.3–50.8 ∘ N and 18–20 ∘ E). The wind-assigned anomaly method is first validated using the CAMS forecast data ( XCH 4 and TXCH 4 ), showing a good agreement with the CAMS GLOBal ANThropogenic emission (CAMS-GLOB-ANT) inventory. It indicates that the wind-assigned method works well. This wind-assigned method is further applied to the TROPOMI XCH 4 and TROPOMI + IASI TXCH 4 by using the Carbon dioxide and Methane (CoMet) inventory derived for the year 2018. The calculated averaged total CH 4 emissions over the USCB region is about 496 kt yr −1 ( 5.9×10 26 molec. s −1 ) for TROPOMI XCH 4 and 437 kt yr −1 ( 5.2×10 26 molec. s −1 ) for TROPOMI + IASI TXCH 4 . These values are very close to the ones given in the E-PRTR inventory (448 kt yr −1 ) and the ones in the CoMet inventory (555 kt yr −1 ), and are thus in agreement with these inventories. The similar estimates of XCH 4 and TXCH 4 also imply that for a strong source, the dynamically induced variations of the CH 4 mixing ratio in the upper troposphere and lower stratosphere region are of secondary importance. Uncertainties from different error sources (background removal and noise ...
Keywords	Physics ; QC1-999 ; Chemistry ; QD1-999
Subject code	511 ; 333
Language	English
Publishing date	2022-08-01T00:00:00Z
Publisher	Copernicus Publications
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Observations of precipitable water vapour over complex topography of Ethiopia from ground-based GPS, FTIR, radiosonde and ERA-Interim reanalysis

G. Mengistu Tsidu / T. Blumenstock / F. Hase

Atmospheric Measurement Techniques Discussions, Vol 7, Iss 9, Pp 9869-

2014 Volume 9915

Abstract: Water vapour is one of the most important green house gases. Long-term changes in the amount of water vapour in the atmosphere need to be monitored not only for its direct role as a green house gas but also because of its role in amplifying other ... ...

Abstract	Water vapour is one of the most important green house gases. Long-term changes in the amount of water vapour in the atmosphere need to be monitored not only for its direct role as a green house gas but also because of its role in amplifying other feedbacks in general circulation models. In recent decades, monitoring of water vapour on regular and continuous basis is becoming possible as a result of increase in the number of deployed Global Positioning Satellite (GPS) ground-based receivers at a faster pace. However, Horn of Africa region remains a data void region in this regard until recently when some GPS ground-receiver stations have been deployed to monitor tectonic movements in the Great Rift Valley. This study seizes this opportunity and the installation of Fourier Transform Infrared Spectrometer (FTIR) at Addis Ababa to assess the quality and comparability of Precipitable Water Vapour (PWV) from GPS, FTIR, radiosonde and ERA-Interim over Ethiopia. The PWVs from the three instruments and reanalysis show good correlation in the range from 0.83 to 0.92. The radiosonde PWV shows dry bias with respect to other observations and reanalysis. ERA-Interim PWV shows wet bias with respect to all while GPS PWV exhibits wet bias with respect to FTIR. The intercomparison between GPS and ERA-Interim is extended to seven other GPS stations in the country. Despite the sensitivity of GPS PWV to uncertainty in surface pressure in general, observed surface pressure is used only at four GPS stations. The gain obtained from using observed surface pressure in terms of reducing bias and strengthening correlation is significant but shows some variations among the GPS sites. In contrast to comparison at Addis Ababa, the comparison between GPS and ERA-Interim PWVs over seven other GPS stations shows difference in the magnitude and sign of bias of ERA-Interim with respect to GPS PWV from station to station. This variation is also visible across different seasons. The main cause of the variation is linked to variation in ECMWF model skill over different regions and seasons which might be related to poor observational constraint from this part of the globe and sensitivity of model convection scheme to orography. The latter is consistent with observed wet bias over some highland stations and dry bias over few lowland stations. However, there are also exceptions to this inference at few stations suggesting other factors such as proximity to water bodies and vegetations might have a role. The skill of ECMWF in reproducing realistic PWV varies with season showing large bias during warm and wet summer for most of the GPS sites.
Keywords	Meteorology. Climatology ; QC851-999 ; Physics ; QC1-999 ; Science ; Q ; Engineering (General). Civil engineering (General) ; TA1-2040 ; Earthwork. Foundations ; TA715-787
Subject code	551
Language	English
Publishing date	2014-09-01T00:00:00Z
Publisher	Copernicus Publications
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: The CO 2 integral emission by the megacity of St Petersburg as quantified from ground-based FTIR measurements combined with dispersion modelling

D. V. Ionov / M. V. Makarova / F. Hase / S. C. Foka / V. S. Kostsov / C. Alberti / T. Blumenstock / T. Warneke / Y. A. Virolainen

Atmospheric Chemistry and Physics, Vol 21, Pp 10939-

2021 Volume 10963

Abstract: The anthropogenic impact is a major factor of climate change, which is highest in industrial regions and modern megacities. Megacities are a significant source of emissions of various substances into the atmosphere, including CO 2 which is the most ... ...

Abstract	The anthropogenic impact is a major factor of climate change, which is highest in industrial regions and modern megacities. Megacities are a significant source of emissions of various substances into the atmosphere, including CO 2 which is the most important anthropogenic greenhouse gas. In 2019 and 2020, the mobile experiment EMME (Emission Monitoring Mobile Experiment) was carried out on the territory of St Petersburg which is the second-largest industrial city in Russia with a population of more than 5 million people. In 2020, several measurement data sets were obtained during the lockdown period caused by the COVID-19 (COronaVIrus Disease of 2019) pandemic. One of the goals of EMME was to evaluate the CO 2 emission from the St Petersburg agglomeration. Previously, the CO 2 area flux has been obtained from the data of the EMME-2019 experiment using the mass balance approach. The value of the CO 2 area flux for St Petersburg has been estimated as being 89±28 kt km −2 yr −1 , which is 3 times higher than the corresponding value reported in the official municipal inventory. The present study is focused on the derivation of the integral CO 2 emission from St Petersburg by coupling the results of the EMME observational campaigns of 2019 and 2020 and the HYSPLIT (HYbrid Single-Particle Lagrangian Integrated Trajectories) model. The ODIAC (Open-Data Inventory for Anthropogenic CO 2 ) database is used as the source of the a priori information on the CO 2 emissions for the territory of St Petersburg. The most important finding of the present study, based on the analysis of two observational campaigns, is a significantly higher CO 2 emission from the megacity of St Petersburg compared to the data of municipal inventory, i.e. <math xmlns="http://www.w3.org/1998/Math/MathML" id="M14" display="inline" overflow="scroll" dspmath="mathml"><mrow><mo>∼</mo><mn mathvariant="normal">75</mn><mspace linebreak="nobreak" width="0.125em"/><mn ...<br />
Keywords	Physics ; QC1-999 ; Chemistry ; QD1-999
Subject code	333 ; 511
Language	English
Publishing date	2021-07-01T00:00:00Z
Publisher	Copernicus Publications
Document type	Article ; Online
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Article ; Online: Camtracker

M. Gisi / F. Hase / S. Dohe / T. Blumenstock

Atmospheric Measurement Techniques, Vol 4, Iss 1, Pp 47-

a new camera controlled high precision solar tracker system for FTIR-spectrometers

2011 Volume 54

Abstract: A new system to very precisely couple radiation of a moving source into a Fourier Transform Infrared (FTIR) Spectrometer is presented. The Camtracker consists of a homemade altazimuthal solar tracker, a digital camera and a homemade program to process ... ...

Abstract	A new system to very precisely couple radiation of a moving source into a Fourier Transform Infrared (FTIR) Spectrometer is presented. The Camtracker consists of a homemade altazimuthal solar tracker, a digital camera and a homemade program to process the camera data and to control the motion of the tracker. The key idea is to evaluate the image of the radiation source on the entrance field stop of the spectrometer. We prove that the system reaches tracking accuracies of about 10 arc s for a ground-based solar absorption FTIR spectrometer, which is significantly better than current solar trackers. Moreover, due to the incorporation of a camera, the new system allows to document residual pointing errors and to point onto the solar disk center even in case of variable intensity distributions across the source due to cirrus or haze.
Keywords	Meteorology. Climatology ; QC851-999 ; Physics ; QC1-999 ; Science ; Q ; DOAJ:Meteorology and Climatology ; DOAJ:Earth and Environmental Sciences ; Environmental engineering ; TA170-171 ; Earthwork. Foundations ; TA715-787
Subject code	620
Language	English
Publishing date	2011-01-01T00:00:00Z
Publisher	Copernicus Publications
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Spatial distributions of X CO 2 seasonal cycle amplitude and phase over northern high-latitude regions

N. Jacobs / W. R. Simpson / K. A. Graham / C. Holmes / F. Hase / T. Blumenstock / Q. Tu / M. Frey / M. K. Dubey / H. A. Parker / D. Wunch / R. Kivi / P. Heikkinen / J. Notholt / C. Petri / T. Warneke

Atmospheric Chemistry and Physics, Vol 21, Pp 16661-

2021 Volume 16687

Abstract: Satellite-based observations of atmospheric carbon dioxide (CO 2 ) provide measurements in remote regions, such as the biologically sensitive but undersampled northern high latitudes, and are progressing toward true global data coverage. Recent ... ...

Abstract	Satellite-based observations of atmospheric carbon dioxide (CO 2 ) provide measurements in remote regions, such as the biologically sensitive but undersampled northern high latitudes, and are progressing toward true global data coverage. Recent improvements in satellite retrievals of total column-averaged dry air mole fractions of CO 2 ( <math xmlns="http://www.w3.org/1998/Math/MathML" id="M5" display="inline" overflow="scroll" dspmath="mathml"><mrow><msub><mi>X</mi><mrow><msub><mi mathvariant="normal">CO</mi><mn mathvariant="normal">2</mn></msub></mrow></msub></mrow></math> <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="25pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="ffa38be111dbfeee63825a71ce00a601"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-21-16661-2021-ie00004.svg" width="25pt" height="14pt" src="acp-21-16661-2021-ie00004.png"/></svg:svg> ) from the NASA Orbiting Carbon Observatory 2 (OCO-2) have allowed for unprecedented data coverage of northern high-latitude regions, while maintaining acceptable accuracy and consistency relative to ground-based observations, and finally providing sufficient data in spring and autumn for analysis of satellite-observed <math xmlns="http://www.w3.org/1998/Math/MathML" id="M6" display="inline" overflow="scroll" dspmath="mathml"><mrow><msub><mi>X</mi><mrow><msub><mi mathvariant="normal">CO</mi><mn mathvariant="normal">2</mn></msub></mrow></msub></mrow></math> <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="25pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="7776a2a308541bd291e7ef776c0343e7"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-21-16661-2021-ie00005.svg" width="25pt" height="14pt" src="acp-21-16661-2021-ie00005.png"/></svg:svg> seasonal cycles ...
Keywords	Physics ; QC1-999 ; Chemistry ; QD1-999
Language	English
Publishing date	2021-11-01T00:00:00Z
Publisher	Copernicus Publications
Document type	Article ; Online
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Article ; Online: Camtracker

M. Gisi / F. Hase / S. Dohe / T. Blumenstock

Atmospheric Measurement Techniques Discussions, Vol 3, Iss 6, Pp 4865-

a new camera controlled high precision solar tracker system for FTIR-spectrometers

2010 Volume 4887

Abstract: A new system to very precisely couple radiation of a moving source into a FTIR-spectrometer is presented. The Camtracker consists of a homemade altazimuthal solar tracker, a digital camera and a homemade program to process the camera data and to control ... ...

Abstract	A new system to very precisely couple radiation of a moving source into a FTIR-spectrometer is presented. The Camtracker consists of a homemade altazimuthal solar tracker, a digital camera and a homemade program to process the camera data and to control the motion of the tracker. The key idea is to evaluate the image of the radiation source on the entrance field stop of the spectrometer. We prove that the system reaches tracking accuracies of about 10" for a ground-based solar absorption FTIR spectrometer, which is significantly better than current solar trackers. Moreover, due to the incorporation of a camera, the new system allows to document residual pointing errors and to point onto the solar disc centre even in case of variable intensity distributions across the source due to cirrus or haze.
Keywords	Meteorology. Climatology ; QC851-999 ; Physics ; QC1-999 ; Science ; Q ; DOAJ:Meteorology and Climatology ; DOAJ:Earth and Environmental Sciences ; Engineering (General). Civil engineering (General) ; TA1-2040 ; Earthwork. Foundations ; TA715-787
Subject code	620
Language	English
Publishing date	2010-11-01T00:00:00Z
Publisher	Copernicus Publications
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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