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- Buehler, Stefan A., et al.
(författare)
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ARTS, the atmospheric radiative transfer simulator
- 2005
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Ingår i: Journal of Quantitative Spectroscopy and Radiative Transfer. - : Elsevier BV. - 0022-4073 .- 1879-1352. ; 91:1, s. 65-93
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Tidskriftsartikel (refereegranskat)abstract
- RTS is a modular program that simulates atmospheric radiative transfer. The paper describes ARTS version 1.0, which is applicable in the absence of scattering. An overview over all major parts of the model is given: calculation of absorption coefficients, the radiative transfer itself, and the calculation of Jacobians. ARTS can be freely used under a GNU general public license. Unique features of the program are its scalability and modularity, the ability to work with different sources of spectroscopic parameters, the availability of several self-consistent water continuum and line absorption models, and the analytical calculation of Jacobians.
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| 2. |
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| 3. |
- Eriksson, Patrick, et al.
(författare)
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ARTS : a modular public domain radiative transfer program
- 2001
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Ingår i: Atmospheric millimeter and sub-millimeter radiative transfer modelling. 2. - Berlin : Dialogos Förlag. - 9783897225855 ; , s. 57-112
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 4. |
- Kuhn, Thomas, 1970-, et al.
(författare)
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Superconducting sub-millimeter wave limb emission sounder SMILES
- 1999
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Ingår i: International Ozone Symposium.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- SMILES is a heterodyne sub-millimeter receiver which will be installed on the ELM-ES platform of the Japanese Experimental Module on the International Space Station in 2003. For the scientific side, the advantage of SIS technology is the up to five times lower system noise temperature of the receiver compared with conventional ones and therefore provides a much better resolution, both in time and space.
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| 5. |
- Verdes, C. L., et al.
(författare)
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Partition function data and impact on retrieval quality for an mm/sub-mm limb sounder
- 2005
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Ingår i: Journal of Quantitative Spectroscopy and Radiative Transfer. - : Elsevier BV. - 0022-4073 .- 1879-1352. ; 90:2, s. 217-238
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Tidskriftsartikel (refereegranskat)abstract
- The partition function plays a major role as it mainly governs the dependence of the spectral line strength (or line intensity) on the temperature. A wrong partition function will lead to an incorrect line strength, which will lead to a systematic error in the retrieval. Therefore, a careful investigation of the available partition function data and the sensitivity of the retrieval to this is required. Two partition function data sets, the HITRAN and the JPL, are considered in this paper. In a first step, we investigate the spread of the partition function ratios from the simple approximation values given by theory. We find that the HITRAN partition functions are usually higher than the values quoted by the simple approximation. The JPL partition functions are much closer to the values given by the approximation. Comparing directly the two datasets, with some exceptions, a good agreement is found. Only for 16 molecules (from 66 considered molecules), the deviations in the two data sets are larger than 2%. The retrieval error analysis shows that, for the case of the molecular species with strong signatures, an uncertainty in the partition function is directly translated into a retrieval error of the species in question. However, the uncertainty in the partition function of this species can have a high impact on the quality of weak species retrieval.
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| 7. |
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| 8. |
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| 9. |
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| 10. |
- von Engeln, Axel, et al.
(författare)
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One-dimensional variational (1-D Var) retrieval of temperature, water vapor, and a reference pressure from radio occultation measurements : A sensitivity analysis
- 2003
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Ingår i: Journal of Geophysical Research. - 0148-0227 .- 2156-2202. ; 108:11, s. 4337-
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Tidskriftsartikel (refereegranskat)abstract
- A 1-D Var retrieval study of simulated radio occultation measurements is presented. Temperature and a water vapor profile are retrieved along with a reference pressure to generate the pressure profile by applying the hydrostatic equation. High-resolution European Center for Medium-Range Weather Forecasts (ECMWF) atmospheric fields are used by a ray tracing tool to calculate the exact positions of the tangent point. The 1-D atmospheric profiles following the calculated tangent point trajectory in the 3-D ECMWF fields are used to simulate bending angle measurements with a 1-D forward model. Assimilation of these bending angles in a 1-D Var tool employing the same 1-D forward model is performed. We analyze the sensitivity of the retrieval to changes in vertical resolution, horizontal smearing of the tangent point trajectory, and the assumption of hydrostatic equilibrium for a nonvertical atmospheric scan. We find that retrievals calculated without adequate vertical resolution can have significant errors in temperature and water vapor. Errors in the retrieval by assuming hydrostatic equilibrium for a nonvertical scan generally cause only minor errors in the retrieved profiles. A study into the occurrence of rays curving down toward the Earth surface indicates that about 5–10% of the profiles could experience so-called critical refraction at altitudes between 0.5 km and 2 km in case of the applied high-resolution ECMWF data.
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