Estimation of a radiative transfer model in the longwave spectral range: sensitivity study and application to real cases

<p>Operational retrievals of tropospheric trace gases from space-borne spectrometers are made using 1D radiative transfer models. To minimize cloud effects generally only partially cloudy pixels are analysed using simplified cloud contamination treatments based on radiometric cloud fraction estimates and photon path length corrections based on oxygen collision pair (O2-O2) or O2A-absorption band measurements. In reality, however, the impact of clouds can be much more complex, involving unresolved sub-pixel clouds, scattering of clouds in neighbouring pixels, and cloud shadow effects, such that 3D radiation scattering from unresolved boundary layer clouds may give significant biases in the trace gas retrievals. In order to quantify this impact, we use the MYSTIC 3D radiative transfer model to generate synthetic data. The realistic 3D cloud fields, needed for MYSTIC input, are generated by the ICOsahedral Non-hydrostatic (ICON) atmosphere model for a region including Germany, the Netherlands and parts of other surrounding countries. The retrieval algorithm is applied to the synthetic data and comparison to the known input trace gas concentrations yields the retrieval error due to 3D cloud effects.&#160;<br>In this study, we study NO2, which is a key tropospheric trace gas measured by TROPOMI and the future atmospheric Sentinels (S4 and S5). The work starts with a sensitivity study for the simulations with a simple 2D box cloud. The influence of cloud parameters (e.g., cloud top height, cloud optical thickness), observation geometry, and spatial resolution are studied, and the most significant dependences of retrieval biases are identified and investigated. Several approaches to correct the NO2 retrieval in the cloud shadow are explored and ultimately applied to both synthetic data with realistic 3D clouds and real observations.</p>

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Radiative Transfer Modeling of Phytoplankton Fluorescence Quenching Processes

Remote Sensing ◽

10.3390/rs10081309 ◽

2018 ◽

Vol 10 (8) ◽

pp. 1309 ◽

Cited By ~ 7

Author(s):

Peng-Wang Zhai ◽

Emmanuel Boss ◽

Bryan Franz ◽

P. Werdell ◽

Yongxiang Hu

Keyword(s):

Quantum Yield ◽

Radiative Transfer ◽

Sensitivity Study ◽

Radiative Transfer Model ◽

Photochemical Quenching ◽

Transfer Model ◽

Fluorescence Signal ◽

New Space ◽

Non Photochemical Quenching ◽

Radiative Transfer Modeling

We report the first radiative transfer model that is able to simulate phytoplankton fluorescence with both photochemical and non-photochemical quenching included. The fluorescence source term in the inelastic radiative transfer equation is proportional to both the quantum yield and scalar irradiance at excitation wavelengths. The photochemical and nonphotochemical quenching processes change the quantum yield based on the photosynthetic active radiation. A sensitivity study was performed to demonstrate the dependence of the fluorescence signal on chlorophyll a concentration, aerosol optical depths and solar zenith angles. This work enables us to better model the phytoplankton fluorescence, which can be used in the design of new space-based sensors that can provide sufficient sensitivity to detect the phytoplankton fluorescence signal. It could also lead to more accurate remote sensing algorithms for the study of phytoplankton physiology.

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On the Improvement of COAMPS Weather Forecasts Using an Advanced Radiative Transfer Model

Weather and Forecasting ◽

10.1175/2008waf2222137.1 ◽

2009 ◽

Vol 24 (1) ◽

pp. 286-306 ◽

Cited By ~ 15

Author(s):

Ming Liu ◽

Jason E. Nachamkin ◽

Douglas L. Westphal

Keyword(s):

Optical Properties ◽

Radiative Transfer ◽

Liquid Water ◽

Atmospheric Stability ◽

Sensitivity Study ◽

Radiative Heating ◽

Radiative Transfer Model ◽

Surface Model ◽

Transfer Model ◽

The Impact

Abstract Fu–Liou’s delta-four-stream (with a two-stream option) radiative transfer model has been implemented in the U.S. Navy’s Coupled Ocean–Atmosphere Mesoscale Prediction System (COAMPS)1 to calculate solar and thermal infrared fluxes in 6 shortwave and 12 longwave bands. The model performance is evaluated at high resolution for clear-sky and overcast conditions against the observations from the Southern Great Plains of the Atmospheric Radiation Measurement Program. In both cases, use of the Fu–Liou model provides significant improvement over the operational implementation of the standard Harshvardhan radiation parameterization in both shortwave and longwave fluxes. A sensitivity study of radiative flux on clouds reveals that the choices of cloud effective radius schemes for ice and liquid water are critical to the flux calculation due to the effects on cloud optical properties. The sensitivity study guides the selection of optimal cloud optical properties for use in the Fu–Liou parameterization as implemented in COAMPS. The new model is then used to produce 3-day forecasts over the continental United States for a winter and a summer month. The verifications of parallel runs using the standard and new parameterizations show that Fu–Liou dramatically reduces the model’s systematic warm bias in the upper troposphere in both winter and summer. The resultant cooling modifies the atmospheric stability and moisture transport, resulting in a significant reduction in the upper-tropospheric wet bias. Overall ice and liquid water paths are also reduced. At the surface, Fu–Liou reduces the negative temperature and sea level pressure biases by providing more accurate radiative heating rates to the land surface model. The error reductions increase with forecast length as the impact of improved radiative fluxes accumulates over time. A combination of the two- and four-stream options results in major computational efficiency gains with minimal loss in accuracy.

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Soil Moisture Retrieval from Passive Microwave Data: A Sensitivity Study Using a Coupled Svat-Radiative Transfer Model at the Upper Danube Anchor Site

IGARSS 2008 - 2008 IEEE International Geoscience and Remote Sensing Symposium ◽

10.1109/igarss.2008.4779084 ◽

2008 ◽

Author(s):

Florian Schlenz ◽

Alexander Loew ◽

Wolfram Mauser

Keyword(s):

Soil Moisture ◽

Radiative Transfer ◽

Sensitivity Study ◽

Passive Microwave ◽

Radiative Transfer Model ◽

Transfer Model ◽

Microwave Data

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Estimation of mineral dust long-wave radiative forcing: sensitivity study to particle properties and application to real cases in the region of Barcelona

Atmospheric Chemistry and Physics ◽

10.5194/acp-14-9213-2014 ◽

2014 ◽

Vol 14 (17) ◽

pp. 9213-9231 ◽

Cited By ~ 35

Author(s):

M. Sicard ◽

S. Bertolín ◽

M. Mallet ◽

P. Dubuisson ◽

A. Comerón

Keyword(s):

Spectral Range ◽

Radiative Forcing ◽

Mineral Dust ◽

Opposite Sign ◽

Sensitivity Study ◽

Short Wave ◽

Radiative Transfer Model ◽

Transfer Model ◽

Radiative Effect ◽

Long Wave

Abstract. The aerosol radiative effect in the long-wave (LW) spectral range is sometimes not taken into account in atmospheric aerosol forcing studies at local scale because the LW aerosol effect is assumed to be negligible. At regional and global scale this effect is partially taken into account: aerosol absorption is taken into account but scattering is still neglected. However, aerosols with strong absorbing and scattering properties in the LW region, like mineral dust, can have a non-negligible radiative effect in the LW spectral range (both at surface and top of the atmosphere) which can counteract their cooling effect occurring in the short-wave spectral range. The first objective of this research is to perform a sensitivity study of mineral dust LW radiative forcing (RF) as a function of dust microphysical and optical properties using an accurate radiative transfer model which can compute vertically resolved short-wave and long-wave aerosol RF. Radiative forcing simulations in the LW range have shown an important sensitivity to the following parameters: aerosol load, radius of the coarse mode, refractive index, aerosol vertical distribution, surface temperature and surface albedo. The scattering effect has been estimated to contribute to the LW RF up to 18% at the surface and up to 38% at the top of the atmosphere. The second objective is the estimation of the short-wave and long-wave dust RF for 11 dust outbreaks observed in Barcelona. At the surface, the LW RF varies between +2.8 and +10.2 W m−2, which represents between 11 and 26% (with opposite sign) of the SW component, while at the top of the atmosphere the LW RF varies between +0.6 and +5.8 W m−2, which represents between 6 and 26% (with opposite sign) of the SW component.

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Vertical profile of tropospheric ozone derived from synergetic retrieval using three different wavelength ranges, UV, IR, and microwave: sensitivity study for satellite observation

Atmospheric Measurement Techniques ◽

10.5194/amt-11-1653-2018 ◽

2018 ◽

Vol 11 (3) ◽

pp. 1653-1668 ◽

Cited By ~ 3

Author(s):

Tomohiro O. Sato ◽

Takao M. Sato ◽

Hideo Sagawa ◽

Katsuyuki Noguchi ◽

Naoko Saitoh ◽

...

Keyword(s):

Radiative Transfer ◽

Tropospheric Ozone ◽

Vertical Profile ◽

Reduction Rate ◽

Estimation Method ◽

Optimal Estimation ◽

Sensitivity Study ◽

Maximum Sensitivity ◽

Radiative Transfer Model ◽

Transfer Model

Abstract. We performed a feasibility study of constraining the vertical profile of the tropospheric ozone by using a synergetic retrieval method on multiple spectra, i.e., ultraviolet (UV), thermal infrared (TIR), and microwave (MW) ranges, measured from space. This work provides, for the first time, a quantitative evaluation of the retrieval sensitivity of the tropospheric ozone by adding the MW measurement to the UV and TIR measurements. Two observation points in East Asia (one in an urban area and one in an ocean area) and two observation times (one during summer and one during winter) were assumed. Geometry of line of sight was nadir down-looking for the UV and TIR measurements, and limb sounding for the MW measurement. The retrieval sensitivities of the ozone profiles in the upper troposphere (UT), middle troposphere (MT), and lowermost troposphere (LMT) were estimated using the degree of freedom for signal (DFS), the pressure of maximum sensitivity, reduction rate of error from the a priori error, and the averaging kernel matrix, derived based on the optimal estimation method. The measurement noise levels were assumed to be the same as those for currently available instruments. The weighting functions for the UV, TIR, and MW ranges were calculated using the SCIATRAN radiative transfer model, the Line-By-Line Radiative Transfer Model (LBLRTM), and the Advanced Model for Atmospheric Terahertz Radiation Analysis and Simulation (AMATERASU), respectively. The DFS value was increased by approximately 96, 23, and 30 % by adding the MW measurements to the combination of UV and TIR measurements in the UT, MT, and LMT regions, respectively. The MW measurement increased the DFS value of the LMT ozone; nevertheless, the MW measurement alone has no sensitivity to the LMT ozone. The pressure of maximum sensitivity value for the LMT ozone was also increased by adding the MW measurement. These findings indicate that better information on LMT ozone can be obtained by adding constraints on the UT and MT ozone from the MW measurement. The results of this study are applicable to the upcoming air-quality monitoring missions, APOLLO, GMAP-Asia, and uvSCOPE.

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Water alteration on (42355) Typhon?

Proceedings of the International Astronomical Union ◽

10.1017/s1743921310001742 ◽

2009 ◽

Vol 5 (S263) ◽

pp. 197-200

Author(s):

Alvaro Alvarez-Candal ◽

Maria Antonietta Barucci

Keyword(s):

Radiative Transfer ◽

Spectral Range ◽

Surface Composition ◽

Parent Body ◽

Radiative Transfer Model ◽

Transfer Model ◽

Large Telescope ◽

Aqueous Alteration ◽

Very Large Telescope ◽

Visible Spectra

AbstractThe visible spectra of (42355) Typhon showed evidence for aqueously altered materials. Therefore we seek to understand if such an event is possible.We use data from the ESO/Very Large Telescope together with the Hapke Hapke radiative transfer model to interpret the surface composition of (42355) Typhon over the whole spectral range (~0.5 − 2.4 μm).Our results points that (42355) Typhon could be a fragment from a larger parent body that suffered aqueous alteration.

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Radiative transfer model STORM for full Stokes vector calculations in the visible and near infrared spectral range

Advances in Radio Science ◽

10.5194/ars-4-329-2006 ◽

2006 ◽

Vol 4 ◽

pp. 329-335

Author(s):

U. Böttger ◽

R. Preusker

Keyword(s):

Remote Sensing ◽

Radiative Transfer ◽

Spectral Range ◽

Near Infrared ◽

Stokes Parameters ◽

Radiative Transfer Model ◽

Transfer Model ◽

Stokes Vector ◽

Infrared Spectral Range ◽

Infrared Spectral

Abstract. Based on the Matrix-Operator Method the radiative transfer code STORM (STOkes vector Radiative transfer Model) is introduced, which was developed in a joint project of DLR and Institut f{ü}r Weltraumwissenschaften-Freie Universität Berlin. STORM calculates the Stokes parameters (I, Q, U, V) in a plane parallel, multi layered atmosphere in the visible and near infrared spectral range. The scattering characteristics of aerosols are determined by Mie theory. The surface represents a Lambertian reflector or a wind ruffled water surface described by Cox-Munk model. The results of one calculation are the upward and downward directed Stokes parameters for one wavelength at a desired number of sun incident and viewing angles at varying altitudes in the principal plane and other azimuth angles. STORM is applied for an analysis in view of designing downward looking Earth observing optical remote sensing systems and values of the degree of polarization are presented as generic basis for remote sensing system design and data processing.

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Vertical profile of tropospheric ozone derived from synergetic retrieval using three different wavelength ranges, UV, IR, and Microwave: sensitivity study for satellite observation

10.5194/amt-2017-98 ◽

2017 ◽

Author(s):

Yasuko Kasai ◽

Tomohiro O. Sato ◽

Takao M. Sato ◽

Hideo Sagawa ◽

Katsuyuki Noguchi ◽

...

Keyword(s):

Radiative Transfer ◽

Vertical Profile ◽

Estimation Method ◽

Optimal Estimation ◽

Satellite Observation ◽

Sensitivity Study ◽

Radiative Transfer Model ◽

Transfer Model ◽

Retrieval Method ◽

Advanced Model

Abstract. We performed a quantitative feasibility study of constraining the vertical profile of the amount of ozone in the troposphere by using a synergetic retrieval method on multiple spectra, i.e., ultraviolet (UV), thermal infrared (TIR) and microwave (MW) ranges, measured from space. Twenty atmospheric scenarios for East Asia in summer and winter seasons were assumed in this study. Geometry of line-of-sight was nadir down-looking for UV and TIR measurements, and limb-sounding for MW measurement. The sensitivities of retrieved ozone in the upper troposphere (UT), middle troposphere (MT) and lowermost troposphere (LMT) were estimated using values of the degree of freedom for signal (DFS), partial column error, and averaging kernel matrix, derived based on the optimal estimation method. The measurement noises were assumed at the same level as the currently available instruments. The weighting functions for the UV, TIR and MW ranges were calculated using the SCIATRAN radiative transfer model, the Line-By-Line Radiative Transfer Model, and the Advanced Model for Atmospheric Terahertz Radiation Analysis and Simulation, respectively. In the UT region, the DFS value was enhanced by about 200 % by adding the MW measurements to the combination of UV and TIR measurements. We found that the DFS value of the LMT ozone was increased by approximately 40 % by adding the MW measurements to the combination of UV and TIR measurements; nevertheless, the MW measurement alone has no sensitivity for the LMT ozone. Better information of the LMT ozone can be educed by adding constraints on the UT and MT ozone from the MW measurement. The results of this study will be implemented in the Japanese air-quality monitoring missions, APOLLO, GMAP-Asia and uvSCOPE.

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