Photoelectron imaging spectrometry: Principle and inversion method

1996 ◽  
Vol 67 (6) ◽  
pp. 2257-2268 ◽  
Author(s):  
C. Bordas ◽  
F. Paulig ◽  
H. Helm ◽  
D. L. Huestis
Keyword(s):  
Inversion Method ◽  
Photoelectron Imaging ◽  
Imaging Spectrometry ◽  
And Inversion

scholarly journals Aerosol microphysical retrievals from Precision Filter Radiometer direct solar radiation measurements and comparison with AERONET

2014 ◽  
Vol 7 (1) ◽  
pp. 99-130 ◽  
Author(s):  
S. Kazadzis ◽  
I. Veselovskii ◽  
V. Amiridis ◽  
J. Gröbner ◽  
A. Suvorina ◽  
...  
Keyword(s):  
Temporal Resolution ◽  
Volume Concentration ◽  
Effective Radius ◽  
Optical Data ◽  
Inversion Method ◽  
High Temporal Resolution ◽  
Random Errors ◽  
Percentage Difference ◽  
Filter Radiometer ◽  
And Inversion

Abstract. Synchronized sun-photometric measurements from the AERONET-CIMEL and GAW-PFR aerosol networks are used to compare retrievals of the aerosol optical depth, effective radius and volume concentration during a high temporal resolution measurement campaign at the Athens site in the Mediterranean Basin from 14–22 July 2009. During this period, direct sun AOD retrievals from both instruments exhibited small differences in the range 0.01–0.02 despite the presence of a strong dust event. In addition to AERONET-CIMEL inversion data, an independent inversion method was applied that involves expanding the particle size distribution in terms of measurement kernels so as to estimate bulk particle parameters from a linear-estimated combination of the input optical data. AOD measurements obtained from both CIMEL and PFR instruments using this method also showed reasonable agreement. For low aerosol loads (AOD < 0.2), measurements of the effective radius by the PFR were found to be −20% to +30% different from CIMEL values for both direct sun data and inversion data. At higher loads (AOD > 0.4), measurements of the effective radius by the PFR are consistently 20% lower than CIMEL for both direct sun and inversion data. Volume concentrations at low aerosol loads from the PFR are up to 80% higher than the CIMEL for direct sun data, but inversion data suggests that volume concentrations from the PFR are up to 20% lower than the CIMEL under these same conditions. At higher loads, the percentage difference in volume concentrations from the PFR and CIMEL is systematically negative with inversion data predicting differences 30% lower than those obtained from direct sun data. An assessment of the effect of errors in the AOD retrieval on the estimation of PFR bulk parameters was made using Monte Carlo simulations and demonstrated that it is possible to estimate the effective radius with an uncertainty below 60% and the volume concentration with an uncertainty below 65% even when AOD < 0.2 and when the input errors are as high as 10%. Highlights – A comparison of high temporal resolution synchronous CIMEL and PFR direct sun AOD measurement retrievals – Calculation of bulk aerosol microphysics parameters using a linear estimation inversion technique – A comparison of retrieved aerosol volume concentrations and effective radii from CIMEL and PFR inversions – An analysis of the sensitivity of PFR retrievals to random errors on the optical input data

scholarly journals Pemisahan Anomali Regional-Residual pada Metode Gravitasi Menggunakan Metode Moving Average, Polynomial dan Inversion

2016 ◽  
Vol 3 (01) ◽  
pp. 10 ◽  
Author(s):  
Jarot Purnomo ◽  
Sorja Koesuma ◽  
Mohtar Yunianto
Keyword(s):  
Average Method ◽  
Moving Average ◽  
Continuation Method ◽  
Inversion Method ◽  
Polynomial Method ◽  
Minimum Error ◽  
Gravity Method ◽  
Upward Continuation ◽  
And Inversion ◽  
Separation Results

<span>It has been done a research about separation of regional-residual anomaly in Gravity method. <span>This research compares the result of three methods i.e. moving average method, polynomial <span>method, and inversion method. The computer program is created using a computer programming <span>Matlab 7. From three methods that have been made, the separation results are compared with<br /><span>results of separation by using Upward Continuation method. From the results of these <span>comparisons will be available an excellent program of regional-residual anomali separation. The <span>results show that in polynomial method of the order 4 obtained similar contour to the separation <span>by Upward Continuation Software. So that the output of this separation will be treated again <span>with Grav2DC software. The output of this software is the density of rock Grav2DC of the study<br /><span>area. Processing results obtained the minimum error of 1.85% for the separation by polynomial <span>method, while for the method of Upward Continuation obtained minimum error of 2.22%. The <span>results obtained show that the separation of regional-residual anomali by polynomial method is <span>similar to separation by Upward Continuation method.</span></span></span></span></span></span></span></span></span></span></span></span><br /></span>

Frequency‐domain acoustic‐wave modeling and inversion of crosshole data: Part II—Inversion method, synthetic experiments and real‐data results

Geophysics ◽  
1995 ◽  
Vol 60 (3) ◽  
pp. 796-809 ◽  
Author(s):  
Zhong‐Min Song ◽  
Paul R. Williamson ◽  
R. Gerhard Pratt
Keyword(s):  
Frequency Domain ◽  
Real Data ◽  
Forward Modeling ◽  
Two Dimensions ◽  
Inversion Method ◽  
Inversion Algorithm ◽  
Data Set ◽  
Wave Inversion ◽  
Full Wave ◽  
And Inversion

In full‐wave inversion of seismic data in complex media it is desirable to use finite differences or finite elements for the forward modeling, but such methods are still prohibitively expensive when implemented in 3-D. Full‐wave 2-D inversion schemes are of limited utility even in 2-D media because they do not model 3-D dynamics correctly. Many seismic experiments effectively assume that the geology varies in two dimensions only but generate 3-D (point source) wavefields; that is, they are “two‐and‐one‐half‐dimensional” (2.5-D), and this configuration can be exploited to model 3-D propagation efficiently in such media. We propose a frequency domain full‐wave inversion algorithm which uses a 2.5-D finite difference forward modeling method. The calculated seismogram can be compared directly with real data, which allows the inversion to be iterated. We use a descents‐related method to minimize a least‐squares measure of the wavefield mismatch at the receivers. The acute nonlinearity caused by phase‐wrapping, which corresponds to time‐domain cycle‐skipping, is avoided by the strategy of either starting the inversion using a low frequency component of the data or constructing a starting model using traveltime tomography. The inversion proceeds by stages at successively higher frequencies across the observed bandwidth. The frequency domain is particularly efficient for crosshole configurations and also allows easy incorporation of attenuation, via complex velocities, in both forward modeling and inversion. This also requires the introduction of complex source amplitudes into the inversion as additional unknowns. Synthetic studies show that the iterative scheme enables us to achieve the theoretical maximum resolution for the velocity reconstruction and that strongly attenuative zones can be recovered with reasonable accuracy. Preliminary results from the application of the method to a real data set are also encouraging.

Research on Applied Mechanics with Reservoir Interwell Dynamic Connectivity Model and Inversion Method in Case of Shut-In Wells

2014 ◽  
Vol 540 ◽  
pp. 296-301 ◽  
Author(s):  
Zhi Jiang Kang ◽  
Hui Zhao ◽  
Hui Zhang ◽  
Yun Zhang ◽  
Ying Li ◽  
...  
Keyword(s):  
Oil Field ◽  
Inversion Method ◽  
Applied Mechanics ◽  
Practical Application ◽  
Reservoir Model ◽  
Connectivity Model ◽  
Interwell Connectivity ◽  
And Inversion ◽  
Novel Model ◽  
Dynamic Connectivity

Due to the limitations that the current interwell connectivity can not consider shut-in wells and the inversion solving method is not reliable, a novel model that can consider the compressibility and shut-in situations is established. In order to further decrease the ill-posedness of the solutions for the connectivity model, a constraint optimization algorithm by using Bayesian theories and projection gradient method are proposed. The tests for a synthetic reservoir model and a real oil field indicate that the proposed methodology can efficiently estimate the interwell connectivity with high precision and reliability for practical application.

Magnetic interface forward and inversion method based on Padé approximation

2016 ◽  
Vol 13 (4) ◽  
pp. 712-720 ◽  
Author(s):  
Chong Zhang ◽  
Da-Nian Huang ◽  
Kai Zhang ◽  
Yi-Tao Pu ◽  
Ping Yu
Keyword(s):  
Padé Approximation ◽  
Inversion Method ◽  
Pade Approximation ◽  
And Inversion

scholarly journals Mapping pan-Arctic methane emissions at high spatial resolution using an adjoint atmospheric transport and inversion method and process-based wetland and lake biogeochemical models

2015 ◽  
Vol 15 (22) ◽  
pp. 32469-32518 ◽  
Author(s):  
Z. Tan ◽  
Q. Zhuang ◽  
D. K. Henze ◽  
C. Frankenberg ◽  
E. Dlugokencky ◽  
...  
Keyword(s):  
High Resolution ◽  
Atmospheric Transport ◽  
Methane Emissions ◽  
The Arctic ◽  
Inversion Method ◽  
Methane Cycle ◽  
Mixing Ratios ◽  
Biogeochemical Models ◽  
Northern Russia ◽  
And Inversion

Abstract. Understanding methane emissions from the Arctic, a fast warming carbon reservoir, is important for projecting changes in the global methane cycle under future climate scenarios. Here we optimize Arctic methane emissions with a nested-grid high-resolution inverse model by assimilating both high-precision surface measurements and column-average SCIAMACHY satellite retrievals of methane mole fraction. For the first time, methane emissions from lakes are integrated into an atmospheric transport and inversion estimate, together with prior wetland emissions estimated by six different biogeochemical models. We find that, the global methane emissions during July 2004–June 2005 ranged from 496.4 to 511.5 Tg yr−1, with wetland methane emissions ranging from 130.0 to 203.3 Tg yr−1. The Arctic methane emissions during July 2004–June 2005 were in the range of 14.6–30.4 Tg yr−1, with wetland and lake emissions ranging from 8.8 to 20.4 Tg yr−1 and from 5.4 to 7.9 Tg yr−1 respectively. Canadian and Siberian lakes contributed most of the estimated lake emissions. Due to insufficient measurements in the region, Arctic methane emissions are less constrained in northern Russia than in Alaska, northern Canada and Scandinavia. Comparison of different inversions indicates that the distribution of global and Arctic methane emissions is sensitive to prior wetland emissions. Evaluation with independent datasets shows that the global and Arctic inversions improve estimates of methane mixing ratios in boundary layer and free troposphere. The high-resolution inversions provide more details about the spatial distribution of methane emissions in the Arctic.

scholarly journals Inter-comparison between the Aerosol Optical Properties Retrieved by Different Inversion Methods from SKYNET Sky Radiometer Observations over Qionghai and Yucheng in China

2019 ◽  
Author(s):  
Zhe Jiang ◽  
Minzheng Duan ◽  
Huizheng Che ◽  
Wenxing Zhang ◽  
Teruyuki Nakajima ◽  
...  
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Complex Refractive Index ◽  
Single Scattering ◽  
Inversion Method ◽  
Aerosol Optical Properties ◽  
Validation Data ◽  
Mean Values ◽  
And Inversion ◽  
Volume Size

Abstract. This study analyzed the aerosol optical properties derived by SKYRAD.pack versions 5.0 and 4.2 using the radiometer measurements over Qionghai and Yucheng in China, two new sites of the sky radiometer network (SKYNET). The volume size distribution retrieved by V5.0 presented bimodal patterns with a 0.1–0.2 μm fine particle mode and a 5–6 μm coarse particle mode both over Qionghai and Yucheng. The differences of the volume size distributions between the two versions were very large for the coarse mode with a radius of over 5 μm. The mean values of single scattering albedo (SSA) at 500 nm retrieved from V5.0 were approximately 0.02 lower, but 0.03 higher than those from V4.2 in Qionghai and Yucheng, respectively. The average imaginary part of the complex refractive index (mi) retrieved from V5.0 at all wavelengths was systemically higher than those by V4.2 over Qionghai. Moreover, the differences between the real parts of the complex refractive index (mr) obtained using the two versions were within 4.25 % both at Yucheng and Qionghai. The seasonal variability of the aerosol properties over Qionghai and Yucheng were investigated based on SKYRAD.pack V5.0. The seasonal average SSA during the winter was larger than those in other seasons in Yucheng, while the lowest SSA values occurred in winter over Qionghai. Meanwhile, the mr showed a minimum in winter over both sites. The results can provide validation data in China for SKYNET to continue improving the data-processing and inversion method. The results provide valuable references for continued improvement of the retrieval algorithms of SKYNET and other aerosol observational networks.

The Electromagnetic Responses of Under Seabed Layer and Inversion Method Study

PIERS Online ◽  
2007 ◽  
Vol 3 (2) ◽  
pp. 197-201 ◽  
Author(s):  
Zhaofa Zeng ◽  
L. H. Wang ◽  
Shengtan Zheng ◽  
F. S. Liu ◽  
Y. M. Wang
Keyword(s):  
Inversion Method ◽  
Electromagnetic Responses ◽  
And Inversion
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