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Parametric rainfall retrieval algorithms for passive microwave radiometers

JOURNAL OF APPLIED METEOROLOGY 2003年第10期42卷 1480-1496页

作者： Shin, DB Kummerow, C Colorado State Univ Dept Atmospher Sci Ft Collins CO 80523 USA George Mason Univ Sch Computat Sci Ctr Earth Observing & Space Res Fairfax VA 22030 USA

A methodology is described to construct fully parametric rainfall retrieval algorithms for a variety of passive microwave sensors that exist today and are planned for the future. The Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI) is used to retrieve nonraining geophysical parameters. The method then blends these background geophysical parameters with three-dimensional precipitation fields obtained by matching the TRMM precipitation radar (PR) reflectivity profiles with cloud-resolving model simulations to produce a consistent three-dimensional atmospheric description. Based upon this common description, radiative transfer simulations corresponding to specific microwave sensors are then employed to compute radiances from clear and rainy scenes, as might be seen by any specified microwave radiometer. Last, a Bayesian retrieval methodology is used in conjunction with this database to derive the most likely surface rainfall as well as its vertical structure. By avoiding any dependencies on specific channels or channel combinations, the technique can readily be adapted to different sensor configurations. The algorithm performance is tested for a variety of sensor designs using synthetic retrievals to demonstrate its capability for consistent rainfall estimates. Whereas actual retrievals would be sensitive to the details of the a priori database construction, results from this study indicate that even modest radiometers can retrieve unbiased rainfall rates when constrained by an a priori database constructed from the TRMM satellite. Random errors are correlated to unobserved variations in the vertical and horizontal structure of the precipitation and, thus, depend upon sensor design specifications. The fidelity of these synthetic retrievals is briefly examined by comparing the simulated brightness temperature (T-b) generated in this study with direct observations by the TRMM TMI. Good physical consistency between the simulated and TRMM observed T(b)s is

关键词： .Rainfall retrieve channels construct ectivity geophysical parameters retrieval algorithms TMI TRMM nonraining passive microwave sensors cloud-resolving

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SCISAT-1: retrieval algorithms, ACE-FTS testing and the ACE database

SCISAT-1: Retrieval algorithms, ACE-FTS testing and the ACE ...

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Conference on Earth Observing Systems VIII

作者： Nassar, R Boone, C Walker, KA McLeod, SD Bernath, PF Univ Waterloo Dept Chem Waterloo ON N2L 3G1 Canada

ISBN: (纸本)0819450243

The SCISAT-1 mission, also known as the Atmospheric Chemistry Experiment (ACE), is a Canadian satellite mission to investigate the chemical and dynamical processes that control the distribution of ozone in the stratosphere and upper troposphere. The satellite is scheduled to launch in August 2003, carrying two main instruments: a high-resolution infrared Fourier transform spectrometer (ACE-FTS) and a dual grating UV-Vis-NIR spectrometer known as MAESTRO (Measurement of Aerosol Extinction in the Stratosphere and Troposphere Retrieved by Occultation) both operating primarily in solar occultation mode. Aspects of the mission pertaining to work done by ACE science team members from the University of Waterloo will be described, such as: the ACE-FTS forward model for retrieval of temperature, pressure and VMR profiles;ACE-FTS instrument testing and results;and the ACE Database along with data storage and processing hardware.

关键词： atmospheric remote sensing Fourier transform spectroscopy retrieval algorithms instrument testing

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A systems approach to GPM dual-frequency retrieval

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IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING 2005年第8期43卷 1816-1826页

作者： Rose, CR Chandrasekar, V Colorado State Univ Ft Collins CO 80523 USA

A systems approach to the development of spaceborne dual-frequency radar retrievals is presented. The necessary integral equations governing the backscatter and forward scatter propagation of electromagnetic waves are redeveloped through the parameters of the drop-size distribution (DSD) namely the median drop diameter, D., and normalized intercept parameter N.. The backward iteration algorithm using these equations is reviewed and cast in terms of a closed-loop control-system model with feedback on measured radar reflectivity values. This model is preferred over the fixed-point method because the closed-loop model calculates and iterates based on the input variables for measured reffectivity instead of using attenuation as a loop control variable. The closed-loop model is examined and analyzed in terms of sensitivity to measurement error and DSD parameters and is used to describe and develop the convergence region of the retrievals in the DSD space. The impact of the convergence region is evaluated to define the relative contribution of the methodology in a global sense. It is shown that about half the rainfall falls into the convergence zone demonstrated in this paper.

关键词： drop-size distribution (DSD) estimation Global Precipitation Measurement (GPM) retrieval algorithms

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Ozone profile retrieval from Stratospheric Aerosol and Gas Experiment (SAGE III) limb scatter measurements

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JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES 2005年第D9期110卷

作者： Rault, DF NASA Langley Res Ctr Hampton VA 23681 USA

[ 1] The ability of SAGE III to retrieve the ozone vertical distribution within the atmosphere from limb scatter measurements is being investigated. The sunlight scattered by atmospheric gases and particulates ( aerosol and clouds) and the Earth's surface is measured and spectrally dispersed by the SAGE III high vertical resolution spectrometer. The spectral data are shown to contain sufficient information to retrieve ozone density from 10 km ( or cloud top) to 50 km at a resolution of about 1 km using ultraviolet and visible channels. Since SAGE III was not designed to operate in limb scatter mode, the radiance measurements are contaminated with significant stray light, and a method had to first be developed and implemented to deconvolve instrumental effects from the data. Furthermore, SAGE III has limited attitude determination capability, and tangent altitude registration has to be derived mostly from measured radiance profiles. Two retrieval algorithms were implemented to infer ozone profiles from measured radiance data: the first one is based on the wavelength triplet method, and the second one uses the multiple linear regression technique. Retrieved ozone profiles are shown for a series of cases and compared with available correlative data measured by ozone sondes, SAGE III in occultation mode, and OSIRIS.

关键词： satellite remote sensing limb scattering retrieval algorithms ozone

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Intercomparison of retrieval codes used for the analysis of high-resolution, ground-based FTIR measurements

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JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER 2004年第1期87卷 25-52页

作者： Hase, F Hannigan, JW Coffey, MT Goldman, A Höpfner, M Jones, NB Rinsland, CP Wood, SW Forschungszentrum Karlsruhe IMK ASF D-76021 Karlsruhe Germany Natl Inst Water & Atmospher Res Ltd Central Otago New Zealand NASA Langley Res Ctr Hampton VA USA Univ Wollongong Dept Chem Wollongong NSW 2522 Australia Univ Denver Dept Phys Denver CO 80208 USA Natl Ctr Atmospher Res Div Atmospher Chem Boulder CO 80303 USA

A rigorous and systematic intercomparison of codes used for the retrieval of trace gas profiles from high-resolution ground-based solar absorption FTIR measurements is presented for the first time. Spectra were analyzed with the two widely used independent, retrieval codes: SFIT2 and PROFFIT9. Vertical profiles Of O-3 HNO3, HDO, and N2O were derived from the same set of typical observed spectra. Analysis Of O-3 was improved by using updated line parameters. It is shown that profiles and total column amounts are in excellent agreement, when similar constraints are applied, and that the resolution kernel matrices are also consistent. Owing to the limited altitude resolution of ground-based observations, the impact of the constraints on the solution is not negligible. It is shown that the results are also compatible for independently chosen constraints. Perspectives for refined constraints are discussed. It can be concluded that the error budget introduced by the radiative transfer code and the retrieval algorithm on total columns deduced from high-resolution ground-based solar FTIR spectra is below 1%. (C) 2004 Elsevier Ltd. All rights reserved.

关键词： infrared spectroscopy atmospheric trace gases radiative transfer retrieval algorithms

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Multi-target retrieval (MTR): the simultaneous retrieval of pressure, temperature and volume mixing ratio profiles from limb-scanning atmospheric measurements

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JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER 2004年第2期84卷 141-157页

作者： Dinelli, BM Alpaslan, D Carlotti, M Magnani, L Ridolfi, M CNR Ist Sci Atmosfera & Clima I-40129 Bologna Italy Univ Bologna Dipartimento Chim Fis & Inorgan I-40136 Bologna Italy

In this paper we describe a retrieval approach for the simultaneous determination of the altitude distributions of p, T and VMR of atmospheric constituents from limb-scanning measurements of the atmosphere. This analysis method, named multi-target retrieval (NITR), has been designed and implemented in a computer code aimed at the analysis of MIPAS-ENVISAT observations;however, the concepts implemented in MTR have a general validity and can be extended to the analysis of all type of limb-scanning observations. In order to assess performance and advantages of the proposed approach, NITR has been compared with the sequential analysis system implemented by ESA as the level-2 processor for MIPAS measurements. The comparison has been performed on a common set of target species and spectral intervals. The performed tests have shown that NITR produces results of better quality than a sequential retrieval. However, he simultaneous retrieval of p, T and water VMR has not lead to satisfactory results below the tropopause, because of the high correlation occurring between p and water VMR in the troposphere. We have shown that this problem can be fixed extending the NITR analysis to at least one further target whose spectral features decouple the retrieval of pressure and water VMR. Ozone was found to be a suitable target for this purpose. The advantages of the NITR analysis system in terms of systematic errors have also been discussed. (C) 2003 Elsevier Ltd. All rights reserved.

关键词： atmosphere satellite measurements retrieval algorithms remote sensing MIPAS

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retrieval of atmospheric ozone and nitrogen dioxide vertical distribution from SAGE III limb scattering measurements

Retrieval of atmospheric ozone and nitrogen dioxide vertical...

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Conference on Remote Sensing of Clouds and the Atmosphere VIII

作者： Rault, DF Loughman, R Sioris, C NASA Langley Res Ctr Hampton VA 23681 USA

ISBN: (纸本)0819451185

The limb scattering radiances measured by SAGE III are analyzed. After accounting for instrument issues, ozone and nitrogen dioxide vertical density profiles are retrieved from the data and compared with results from other instruments. These initial results are very promising and show the potential of SAGE III to operate in this mode.

关键词： satellite remote sensing limb scattering retrieval algorithms ozone nitrogen dioxide

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Ozone, NO₂ and aerosol retrieval from SAGE III limb scatter measurements

Ozone, NO<sub>2</sub> and aerosol retrieval from SAGE III li...

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Conference on Remote Sensing of Clouds and the Atmosphere IX

作者： Rault, DF NASA Langley Res Ctr Hampton VA 23681 USA

ISBN: (纸本)0819455180

The ability of SAGE III to retrieve ozone, NO2 and aerosol vertical distribution within Earth atmosphere from limb scatter measurements is being investigated. The sunlight scattered by atmospheric gases and particulates (aerosol, clouds) and the Earth's surface is measured and spectrally dispersed by SAGE III spectrometer. Ozone density vertical profiles are retrieved from 10 km (or cloud top) to 50 km at a resolution of about 1 km and a precision of less than 10% using Chappuis and Huggins ozone absorption bands. NO2 vertical density profiles are retrieved from 15 to 40 kin at a resolution of about 2 km and a precision of 20% using the NO2 absorption features in the 430-450 nm spectral range. Aerosol extinction vertical profiles (from 15 to 30 km) are retrieved using a series of non absorbing channels. Retrieved products are compared with available correlative data (ozone sondes, SAGE III in occultation, OSIRIS).

关键词： satellite remote sensing limb scatter retrieval algorithms ozone NO2 aerosol

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Combined spectral and imaging IR sensor system for analysis of fires and retrieval of fire parameters

Combined spectral and imaging IR sensor system for analysis ...

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Conference on Remote Sensing for Environmental Monitoring, GIS Applications and Geology IV

作者： Kick, H Beier, K Lindermeir, E DLR German Aerosp Ctr Remot Sensing Technol Inst D-82234 Wessling Germany

ISBN: (纸本)0819455210

The infrared sensor system FASA (Fire Airborne Spectral Analyser) operated in a DLR research aircraft is a unique combination of an imager and a Fourier Transform Spectrometer used to detect, analyse and classify fires and volcanoes. In such cases, the scenes in the FTS field of view are generally inhomogeneous and not known a priori, and the data fusion approach of image and spectral data is supposed to overcome the difficulty hereby involved. The analysis of an artificial coal fire has provided us fundamental insights in how to model such fires and potential strategies for data evaluation. First and promising results will be presented. Moreover, the importance of aerosol contributions is examined and the feasibility to retrieve smoke particle parameters in the infrared is demonstrated.

关键词： spectral and imaging IR sensor system fire analysis retrieval algorithms

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Linearized vector radiative transfer model MCC plus plus for a spherical atmosphere

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JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER 2004年第1-3期88卷 297-317页

作者： Postylyakov, OV Russian Acad Sci AM Obukhov Inst Atmospher Phys Moscow 119017 Russia Finnish Meteorol Inst FIN-00101 Helsinki Finland

Application of radiative transfer models has shown that optical remote sensing requires extra characteristics of radiance field in addition to the radiance intensity itself. Simulation of spectral measurements, analysis of retrieval errors and development of retrieval algorithms are in need of derivatives of radiance with respect to atmospheric constituents under investigation. The presented vector spherical radiative transfer model MCC++ was linearized, which allows the calculation of derivatives of all elements of the Stokes vector with respect to the volume absorption coefficient simultaneously with radiance calculation. The model MCC++ employs Monte Carlo algorithm for radiative transfer simulation and takes into account aerosol and molecular scattering, gas and aerosol absorption, and Lambertian surface albedo. The model treats a spherically symmetrical atmosphere. Relation of the estimated derivatives with other forms of radiance derivatives: the weighting functions used in gas retrieval and the air mass factors used in the DOAS retrieval algorithms, is obtained. Validation of the model against other radiative models is over-viewed. The computing time of the intensity for the MCC++ model is about that for radiative models treating sphericity of the atmosphere approximately and is significantly shorter than that for the full spherical models used in the comparisons. The simultaneous calculation of all derivatives (i.e. with respect to absorption in all model atmosphere layers) and the intensity is only 1.2-2 times longer than the calculation of the intensity only. (C) 2004 Elsevier Ltd. All rights reserved.

关键词： radiative transfer polarization derivatives weighting functions air mass factors remote sensing inverse problems retrieval algorithms

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