scholarly journals A compact and low resolution spectrometer for the inversion of water vapor total column amounts

2013 ◽  
Author(s):  
E. Sepúlveda ◽  
M. Schneider ◽  
F. Hase ◽  
O. E. García ◽  
M. Gisi ◽  
...  
Keyword(s):  
Water Vapor ◽  
Low Resolution ◽  
Resolution Spectrometer ◽  
Total Column

scholarly journals Water vapor total column measurements using the Elodie Archive at Observatoire de Haute Provence from 1994 to 2004

2009 ◽  
Vol 2 (2) ◽  
pp. 1075-1097
Author(s):  
A. Sarkissian ◽  
J. Slusser
Keyword(s):  
Water Vapor ◽  
Water Vapor Absorption ◽  
The Earth ◽  
Vapor Absorption ◽  
On Line ◽  
High Resolution Spectrometer ◽  
Long Term Trend ◽  
Resolution Spectrometer ◽  
Total Column

Abstract. Water vapor total column measurements at Observatoire de Haute Provence (5°42' E, +43°55' N), south of France, were obtained using observations of astronomical objects made between July 1994 and December 2004 on the 193-cm telescope with the high-resolution spectrometer Elodie. Spectra of stars, nebulae, and other astronomical objects were taken regularly during 10 years. More than 18 000 spectra from 400 nm to 680 nm are available on-line in the Elodie Archive. This archive, usually explored by astronomers, contains information to study the atmosphere of the Earth. Water vapor absorption lines appear in the visible in delimited bands that astronomers often avoid for their spectral analysis. We used the Elodie Archive with two objectives: firstly, to retrieve seasonal variability and long-term trend of atmospheric water vapor, and secondly, to remove signatures in spectra for further astronomical or geophysical use. The tools presented here are developed following, when possible, formats and standards recommended by the International Virtual Observatory Alliance.

scholarly journals Water vapor total column measurements using the Elodie Archive at Observatoire de Haute Provence from 1994 to 2004

2009 ◽  
Vol 2 (2) ◽  
pp. 319-326 ◽  
Author(s):  
A. Sarkissian ◽  
J. Slusser
Keyword(s):  
Water Vapor ◽  
Water Vapor Absorption ◽  
The Earth ◽  
Vapor Absorption ◽  
On Line ◽  
High Resolution Spectrometer ◽  
Long Term Trend ◽  
Resolution Spectrometer ◽  
Total Column

Abstract. Water vapor total column measurements at Observatoire de Haute Provence (5°42´ E, +43°55´ N), south of France, were obtained using observations of astronomical objects made between July 1994 and December 2004 on the 193-cm telescope with the high-resolution spectrometer Elodie. Spectra of stars, nebulae, and other astronomical objects were taken regularly during 10 years. More than 18 000 spectra from 400 nm to 680 nm are available on-line in the Elodie Archive. This archive, usually explored by astronomers, contains information to study the atmosphere of the Earth. Water vapor absorption lines appear in the visible in delimited bands that astronomers often avoid for their spectral analysis. We used the Elodie Archive with two objectives: firstly, to retrieve seasonal variability and long-term trend of atmospheric water vapor, and secondly, to remove signatures in spectra for further astronomical or geophysical use. The tools presented here (the workflow, the interoperable Elodie Archive and the web service Tellodie) are developed following, when possible, formats and standards recommended by the International Virtual Observatory Alliance.

scholarly journals The mid-infrared instrument for the James Webb Space Telescope: performance and operation of the Low-Resolution Spectrometer

2016 ◽  
Author(s):  
Sarah Kendrew ◽  
Silvia Scheithauer ◽  
Patrice Bouchet ◽  
Jerome Amiaux ◽  
Ruymán Azzollini ◽  
...  
Keyword(s):  
Low Resolution ◽  
Mid Infrared ◽  
Space Telescope ◽  
James Webb Space Telescope ◽  
Resolution Spectrometer

scholarly journals Asian water tower evinced in total column water vapor: a comparison among multiple satellite and reanalysis data sets

2019 ◽  
Vol 54 (1-2) ◽  
pp. 231-245 ◽  
Author(s):  
Yin Zhao ◽  
Tianjun Zhou
Keyword(s):  
Water Vapor ◽  
Satellite Data ◽  
Annual Cycle ◽  
Reanalysis Data ◽  
Radiosonde Data ◽  
Data Sets ◽  
Important Indicator ◽  
Ensemble Mean ◽  
Asian Water ◽  
Total Column

Abstract The total column water vapor (TCWV) over the Tibetan Plateau (TP) is one important indicator of the Asian water tower, and the changes in the TCWV are vital to the climate and ecosystem in downstream regions. However, the observational data is insufficient to understand the changes in the TCWV due to the high elevation of the TP. Satellite and reanalysis data can be used as substitutes, but their quality needs to be evaluated. In this study, based on a homogenized radiosonde data set, a comprehensive evaluation of the TCWV over the TP derived from two satellite data sets (AIRS-only and AIRS/AMSU) and seven existing reanalysis data sets (MERRA, MERRA2, NCEP1, NCEP2, CFSR, ERA-I, JRA55) is performed in the context of the climatology, annual cycle and interannual variability. Both satellite data sets reasonably reproduce the characteristics of the TCWV over the TP. All reanalysis data sets perform well in reproducing the annual mean climatology of the TCWV over the TP (R = 0.99), except for NCEP1 (R = 0.96) and NCEP2 (R = 0.92). ERA-I is more reliable in capturing the spatial pattern of the annual cycle (R = 0.94), while NCEP1 shows the lowest skill (R = 0.72). JRA55 performs best in capturing the features of the interannual coherent variation (EOF1, R = 0.97). The skill-weighted ensemble mean of the reanalysis data performs better than the unweighted ensemble mean and most of the single reanalysis data sets. The evaluation provides essential information on both the strengths and weaknesses of the major satellite and reanalysis data sets in measuring the total column water vapor over the TP.

scholarly journals Classification of C-Rich Stars According to Their Mid-IR Signatures

1989 ◽  
Vol 106 ◽  
pp. 54-54
Author(s):  
R. Papoular
Keyword(s):  
Relative Abundance ◽  
Morphological Analysis ◽  
Low Resolution ◽  
Colour Temperature ◽  
Resolution Spectrometer

The spectra of the IRAS low-resolution-spectrometer in tape form have been submitted to a systematic morphological analysis, using classical quantitative discriminants (O.Gal et al. 1987, A & A 183, 29; Y. Baron et al. 1987, A & A 186, 271; R. Papoular 1988, A & A , in press). Spectra which display the 11.5μ feature of SiC fall into 4 classes of average spectral excesses. They differ by the width of the SiC feature and by the presence or absence of secondary features at ~8.6, ~11.7 and ~12.8μm.A majority of these spectra have a lower 12-25μm colour temperature than do most optically selected C-stars, presumably because of thicker dust envelopes. While most spectra belong to LRS class 4n, 20% of the total were found among the brightest 20% of the much larger class In, suggesting that the relative abundance of C-stars is much higher than previously assumed.

scholarly journals An IRAS-based search for new dusty WCL Wolf-Rayet stars

1995 ◽  
Vol 163 ◽  
pp. 359-362
Author(s):  
Martin Cohen
Keyword(s):  
Point Source ◽  
Optical Spectroscopy ◽  
Infrared Astronomy ◽  
Low Resolution ◽  
Full Resolution ◽  
Resolution Spectrometer ◽  
Colour Indices ◽  
Point Source Catalog

I have examined all InfraRed Astronomy Satellite (IRAS) data relevant to the 173 galactic Wolf-Rayet (WR) stars in an updated catalogue provided by van der Hucht (priv. comm.), including the 13 stars newly discovered by Shara et al. (1991). Using the exact coordinates given in these lists, I have examined the IRAS Point Source Catalog (PSC), the Faint Source Catalog, Faint Source Reject Catalog, and generated 1-dimensional spatial profiles (“ADDSCAN”s), and 2-dimensional full-resolution images (“FRESCO”s). The goal was to assemble the best set of observed IRAS colour indices for different WR types, in particular for known dusty WCL objects. These colour indices define zones in the IRAS colour-colour plane. By searching the PSC for otherwise unassociated sources that satisfy these colours, I have identified potential new WR candidates, too faint to have been recognized in previous optical searches. I have extracted these candidates' IRAS Low Resolution Spectrometer (LRS) data and compared the spectra with the highly characteristic LRS shape for known dusty WCL stars. Any surviving candidates must now be examined by optical spectroscopy. This work represents a much more rigorous and exhaustive version of the LRS study that identified IRAS 17380-3031 (WR98a) as the first new WR (WC9) star discovered by IRAS (Cohen et al. 1991).

scholarly journals Validation and update of OMI Total Column Water Vapor product

2016 ◽  
Vol 16 (17) ◽  
pp. 11379-11393 ◽  
Author(s):  
Huiqun Wang ◽  
Gonzalo Gonzalez Abad ◽  
Xiong Liu ◽  
Kelly Chance
Keyword(s):  
Water Vapor ◽  
Liquid Water ◽  
Retrieval Algorithm ◽  
Ozone Monitoring Instrument ◽  
Validation Data ◽  
Data Set ◽  
Wide Range ◽  
Key Factor ◽  
The Mean ◽  
Total Column

Abstract. The collection 3 Ozone Monitoring Instrument (OMI) Total Column Water Vapor (TCWV) data generated by the Smithsonian Astrophysical Observatory's (SAO) algorithm version 1.0 and archived at the Aura Validation Data Center (AVDC) are compared with NCAR's ground-based GPS data, AERONET's sun-photometer data, and Remote Sensing System's (RSS) SSMIS data. Results show that the OMI data track the seasonal and interannual variability of TCWV for a wide range of climate regimes. During the period from 2005 to 2009, the mean OMI−GPS over land is −0.3 mm and the mean OMI−AERONET over land is 0 mm. For July 2005, the mean OMI−SSMIS over the ocean is −4.3 mm. The better agreement over land than over the ocean is corroborated by the smaller fitting residuals over land and suggests that liquid water is a key factor for the fitting quality over the ocean in the version 1.0 retrieval algorithm. We find that the influence of liquid water is reduced using a shorter optimized retrieval window of 427.7–465 nm. As a result, the TCWV retrieved with the new algorithm increases significantly over the ocean and only slightly over land. We have also made several updates to the air mass factor (AMF) calculation. The updated version 2.1 retrieval algorithm improves the land/ocean consistency and the overall quality of the OMI TCWV data set. The version 2.1 OMI data largely eliminate the low bias of the version 1.0 OMI data over the ocean and are 1.5 mm higher than RSS's “clear” sky SSMIS data in July 2005. Over the ocean, the mean of version 2.1 OMI−GlobVapour is 1 mm for July 2005 and 0 mm for January 2005. Over land, the version 2.1 OMI data are about 1 mm higher than GlobVapour when TCWV  <  15 mm and about 1 mm lower when TCWV  >  15 mm.

scholarly journals The GEWEX Water Vapor Assessment: Results from Intercomparison, Trend, and Homogeneity Analysis of Total Column Water Vapor

2016 ◽  
Vol 55 (7) ◽  
pp. 1633-1649 ◽  
Author(s):  
Marc Schröder ◽  
Maarit Lockhoff ◽  
John M. Forsythe ◽  
Heather Q. Cronk ◽  
Thomas H. Vonder Haar ◽  
...  
Keyword(s):  
Time Series ◽  
Water Vapor ◽  
Water Cycle ◽  
Regular Grid ◽  
Homogeneity Analysis ◽  
Global Energy ◽  
Spatial Features ◽  
Ensemble Mean ◽  
Total Column ◽  
Observing Systems

AbstractThe Global Energy and Water Cycle Exchanges project (GEWEX) water vapor assessment’s (G-VAP) main objective is to analyze and explain strengths and weaknesses of satellite-based data records of water vapor through intercomparisons and comparisons with ground-based data. G-VAP results from the intercomparison of six total column water vapor (TCWV) data records are presented. Prior to the intercomparison, the data records were regridded to a common regular grid of 2° × 2° longitude–latitude. All data records cover a common period from 1988 to 2008. The intercomparison is complemented by an analysis of trend estimates, which was applied as a tool to identify issues in the data records. It was observed that the trends over global ice-free oceans are generally different among the different data records. Most of these differences are statistically significant. Distinct spatial features are evident in maps of differences in trend estimates, which largely coincide with maxima in standard deviations from the ensemble mean. The penalized maximal F test has been applied to global ice-free ocean and selected land regional anomaly time series, revealing differences in trends to be largely caused by breakpoints in the different data records. The time, magnitude, and number of breakpoints typically differ from region to region and between data records. These breakpoints often coincide with changes in observing systems used for the different data records. The TCWV data records have also been compared with data from a radiosonde archive. For example, at Lindenberg, Germany, and at Yichang, China, such breakpoints are not observed, providing further evidence for the regional imprint of changes in the observing system.

scholarly journals High-accuracy measurements of total column water vapor from the Orbiting Carbon Observatory-2

2016 ◽  
Vol 43 (23) ◽  
pp. 12,261-12,269 ◽  
Author(s):  
Robert R. Nelson ◽  
David Crisp ◽  
Lesley E. Ott ◽  
Christopher W. O'Dell
Keyword(s):  
Water Vapor ◽  
High Accuracy ◽  
Total Column
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