Temperature and pressure retrievals from O2 A-band absorption measurements made by ILAS: retrieval algorithm and error analyses

2001 ◽  
Author(s):  
Takafumi Sugita ◽  
Tatsuya Yokota ◽  
Teruyuki Nakajima ◽  
Hideaki Nakajima ◽  
Katsunori Waragai ◽  
...  
Keyword(s):  
Retrieval Algorithm ◽  
Error Analyses ◽  
Band Absorption ◽  
Temperature And Pressure ◽  
Absorption Measurements

Detection of hogwash oil in Chinese soybean oils using dual-band absorption measurements

2013 ◽  
Author(s):  
A. G. Mignani ◽  
L. Ciaccheri ◽  
A. A. Mencaglia ◽  
J. Xing ◽  
X. Yang ◽  
...  
Keyword(s):  
Dual Band ◽  
Soybean Oils ◽  
Band Absorption ◽  
Absorption Measurements

Total Band Absorption Models for Absorbing-Emitting Liquids: CCl4

1974 ◽  
Vol 96 (1) ◽  
pp. 27-31 ◽  
Author(s):  
J. L. Novotny ◽  
D. E. Negrelli ◽  
T. Van den Driessche
Keyword(s):  
Narrow Band ◽  
Absorption Process ◽  
Absorption Data ◽  
Gas Radiation ◽  
Spectral Integration ◽  
Absorption Models ◽  
Spectroscopic Information ◽  
Band Absorption ◽  
Two Parameter ◽  
Absorption Measurements

Predictions of the total band absorption are useful for describing the absorption process in calculations dealing with radiation interaction in absorbing-emitting liquids. Two two-parameter models, similar to the Elsasser and the statistical narrow band models used in gas radiation work, are developed for predicting the total band absorption in regions of the liquid CCl4 spectrum. The parameters, which are considered to be adjustable, can be determined from experimental total band absorption data or, if available, basic spectroscopic information. Results from the models are compared to experimental total band absorption measurements for CCl4 as well as a prediction based on spectral integration.

scholarly journals New temperature and pressure retrieval algorithm for high-resolution infrared solar occultation spectroscopy: analysis and validation against ACE-FTS and COSMIC

2015 ◽  
Vol 8 (10) ◽  
pp. 10823-10873 ◽  
Author(s):  
K. S. Olsen ◽  
G. C. Toon ◽  
C. D. Boone ◽  
K. Strong
Keyword(s):  
High Resolution ◽  
Atmospheric Chemistry ◽  
Primary Component ◽  
Retrieval Algorithm ◽  
Cold Bias ◽  
Vertical Profiles ◽  
Solar Occultation ◽  
Spatial Coverage ◽  
Temperature And Pressure ◽  
Mean Differences

Abstract. Motivated by the initial selection of a high-resolution solar occultation Fourier transform spectrometer (FTS) to fly to Mars on the ExoMars Trace Gas Orbiter, we have been developing algorithms for retrieving volume mixing ratio vertical profiles of trace gases, the primary component of which is a new algorithm and software for retrieving vertical profiles of temperature and pressure from the spectra. In contrast to Earth-observing instruments, which can rely on accurate meteorological models, a priori information, and spacecraft position, Mars retrievals require a method with minimal reliance on such data. The temperature and pressure retrieval algorithms developed for this work were evaluated using Earth-observing spectra from the Atmospheric Chemistry Experiment (ACE) FTS, a solar occultation instrument in orbit since 2003, and the basis for the instrument selected for a Mars mission. ACE-FTS makes multiple measurements during an occultation, separated in altitude by 1.5–5 km, and we analyze 10 CO2 vibration-rotation bands at each altitude, each with a different usable altitude range. We describe the algorithms and present results of their application and their comparison to the ACE-FTS data products. The Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) provides vertical profiles of temperature up to 40 km with high vertical resolution. Using six satellites and GPS radio occultation, COSMIC's data product has excellent temporal and spatial coverage, allowing us to find coincident measurements with ACE with very tight criteria: less than 1.5 h and 150 km. We present an inter-comparison of temperature profiles retrieved from ACE-FTS using our algorithm, that of the ACE Science Team (v3.5), and from COSMIC. When our retrievals are compared to ACE-FTS v3.5, we find mean differences between −5 and +2 K, and that our retrieved profiles have no seasonal or zonal biases, but do have a warm bias in the stratosphere and a cold bias in the mesosphere. When compared to COSMIC, we do not observe a warm/cool bias and mean differences are between −4 and +1 K. COSMIC comparisons are restricted to below 40 km, where our retrievals have the best agreement with ACE-FTS v3.5. When comparing ACE-FTS v3.5 to COSMIC we observe a cold bias in COSMIC of 0.5 K, and mean differences are between −0.9 and +0.6 K.

scholarly journals Shipborne solar absorption measurements of CO<sub>2</sub>, CH<sub>4</sub>, N<sub>2</sub>O and CO and comparison with SCIAMACHY WFM-DOAS retrievals

2005 ◽  
Vol 5 (1) ◽  
pp. 847-862
Author(s):  
T. Warneke ◽  
R. de Beek ◽  
M. Buchwitz ◽  
J. Notholt ◽  
A. Schulz ◽  
...  
Keyword(s):  
Reasonable Agreement ◽  
Weighting Function ◽  
Optical Absorption Spectroscopy ◽  
Retrieval Algorithm ◽  
Satellite Measurements ◽  
Solar Absorption ◽  
Mixing Ratios ◽  
Latitudinal Variations ◽  
Absorption Measurements ◽  
Better Than

Abstract. CO, CH4, N2O and CO2 were retrieved from high resolution solar absorption spectra obtained during a ship cruise from Capetown to Bremerhaven in January/February 2003 by Fourier Transform Infrared (FTIR) spectroscopy. Precisions of better than 0.5% for the column averaged volume mixing ratios (VMR) of CH4 and CO2 are achieved using of O2 as a reference gas. Shipborne FTIR-measurements of CO and data from SCIAMACHY/ENVISAT retrieved by the Weighting Function Modified Differential Optical Absorption Spectroscopy (WFM-DOAS) retrieval algorithm show qualitatively the same latitudinal variations. WFM-DOAS data of CH4, N2O and CO2 measured over sea exhibit a great spread. The spread is significantly reduced for satellite measurements over land and a reasonable agreement can be obtained if the shipborne data is compared with the closest SCIAMACHY measurements over land. The number of comparisons is too small to draw conclusions. However, by including only WFM-DOAS data with small errors the shipborne and WFM-DOAS data compare within 5% for CH4 and CO2 and within 30% for N2O.

North Alabama Lightning Mapping Array (LMA): VHF Source Retrieval Algorithm and Error Analyses

2004 ◽  
Vol 21 (4) ◽  
pp. 543-558 ◽  
Author(s):  
W. J. Koshak ◽  
R. J. Solakiewicz ◽  
R. J. Blakeslee ◽  
S. J. Goodman ◽  
H. J. Christian ◽  
...  
Keyword(s):  
Retrieval Algorithm ◽  
Error Analyses ◽  
Mapping Array ◽  
Source Retrieval

scholarly journals Shipborne solar absorption measurements of CO<sub>2</sub>, CH<sub>4</sub>, N<sub>2</sub>O and CO and comparison with SCIAMACHY WFM-DOAS retrievals

2005 ◽  
Vol 5 (8) ◽  
pp. 2029-2034 ◽  
Author(s):  
T. Warneke ◽  
R. de Beek ◽  
M. Buchwitz ◽  
J. Notholt ◽  
A. Schulz ◽  
...  
Keyword(s):  
Reasonable Agreement ◽  
Weighting Function ◽  
Optical Absorption Spectroscopy ◽  
Retrieval Algorithm ◽  
Satellite Measurements ◽  
Solar Absorption ◽  
Mixing Ratios ◽  
Latitudinal Variations ◽  
Absorption Measurements ◽  
Better Than

Abstract. CO, CH4, N2O and CO2 were retrieved from high resolution solar absorption spectra obtained during a ship cruise from Capetown to Bremerhaven in January/February 2003 by Fourier Transform Infrared (FTIR) spectroscopy. Precisions of better than 0.5% for the column averaged volume mixing ratios (VMR) of CH4 and CO2 are achieved using of O2 as a reference gas. Shipborne FTIR-measurements of CO and data from SCIAMACHY/ENVISAT retrieved by the Weighting Function Modified Differential Optical Absorption Spectroscopy (WFM-DOAS) retrieval algorithm show qualitatively the same latitudinal variations. WFM-DOAS data of CH4, N2O and CO2 measured over sea exhibit a great spread. The spread is significantly reduced for satellite measurements over land and a reasonable agreement can be obtained if the shipborne data are compared with the closest SCIAMACHY measurements over land. The number of comparisons is too small to draw conclusions. However, by including only WFM-DOAS data with small errors the shipborne and WFM-DOAS data compare within 5% for CH4 and CO2 and within 30% for N2O.

scholarly journals An Algorithm for Retrieving Precipitable Water Vapor over Land Based on Passive Microwave Satellite Data

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Fang-Cheng Zhou ◽  
Xiaoning Song ◽  
Pei Leng ◽  
Hua Wu ◽  
Bo-Hui Tang
Keyword(s):  
Water Vapor ◽  
Root Mean Square Error ◽  
Land Surface ◽  
Precipitable Water ◽  
Precipitable Water Vapor ◽  
Passive Microwave ◽  
Retrieval Algorithm ◽  
Mean Square ◽  
Error Analyses ◽  
Liquid Water In Clouds

Precipitable water vapor (PWV) is one of the most variable components of the atmosphere in both space and time. In this study, a passive microwave-based retrieval algorithm for PWV over land without land surface temperature (LST) data was developed. To build the algorithm, two assumptions exist: (1) land surface emissivities (LSE) at two adjacent frequencies are equal and (2) there are simple parameterizations that relate transmittance, atmospheric effective radiating temperature, and PWV. Error analyses were performed using radiosonde sounding observations from Zhangye, China, and CE318 measurements of Dalanzadgad (43°34′37′′N, 104°25′8′′E) and Singapore (1°17′52′′N, 103°46′48′′E) sites from Aerosol Robotic Network (AERONET), respectively. In Zhangye, the algorithm had a Root Mean Square Error (RMSE) of 4.39 mm and a bias of 0.36 mm on cloud-free days, while on cloudy days there was an RMSE of 4.84 mm and a bias of 0.52 mm because of the effect of liquid water in clouds. The validations in Dalanzadgad and Singapore sites showed that the retrieval algorithm had an RMSE of 4.73 mm and a bias of 0.84 mm and the bigger errors appeared when the water vapor was very dry or very moist.

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