Siegfried Hilgers

Error analysis and minimum bound method for atmospheric remote sensing (2007)

Doicu, Adrian, Schreier, Franz, Hilgers, Siegfried, Hess, Michael

In this study, we present an error analysis for Tikhonov regularization in a semi-stochastic setting. The analysis is carried out in such a way that it can be applied to any kind of inverse problem...

An efficient inversion algorithm for atmospheric remote sensing with application to UV limb observations (2007)

Doicu, Adrian, Schreier, Franz, Hilgers, Siegfried, Von Bargen, Albrecht, Slijkhuis, Sander, Hess, Michael, ...

In this paper we present a retrieval algorithm for atmospheric remote sensing. The algorithm combines Tikhonov regularization and the iteratively regularized Gauss Newton method and is devoted to the...

Information operator approach and iterative regularization methods for atmospheric remote sensing (2007)

Doicu, Adrian, Hilgers, Siegfried, Von Bargen, Albrecht, Rozanov, Alexei, Eichmann, Kai-Uwe, Von Savigny, Christian, ...

In this study, we present the main features of the information operator approach for solving linear inverse problems arising in atmospheric remote sensing. This method is superior to the stochastic...

Use of a Maximum Entropy Method as a Regularization Technique during the Retrieval of Trace Gas Profiles from Limb Sounding Measurements (2006)

Steinwagner, Jörg, Schwarz, Gottfried, Hilgers, Siegfried

We compare regularization techniques during the retrieval of trace gas profiles from limb sounding measurements. In particular, we investigate the performance of a dedicated maximum entropy method.

MIPAS Data Quality - Lessons Learned (2006)

Schwarz, Gottfried, Hilgers, Siegfried

we outline how data quality of the MIPAS products can be monitored.

Multi-parameter regularization method for atmospheric remote sensing (2005)

Doicu, Adrian, Schreier, Franz, Hilgers, Siegfried, Hess, Michael

The iteratively regularized Gauss-Newton algorithm with simple bounds on the variables is extended to the multi-parameter case. The global regularization matrix is computed by using the L-curve...

Analysis of Methane Isopleths using MIPAS Data (2004)

Schwarz, Gottfried, Hilgers, Siegfried, Drescher, Armin

Geographische Unterschiede in Methan-Isoplethen sind in den Daten des Instruments MIPAS klar zu erkennen.

Performance Verification of Two ENVISAT Limb Sounding Processors (2004)

Hilgers, Siegfried, Schwarz, Gottfried, Slijkhuis, Sander

Ein Vergleich von zwei Limb-Sounding-Prozessoren für zeigt typische Gemeinsamkeiten und Unterschiede.

Advanced MIPAS-Level-2 Data Analysis (AMIL2DA) (2003)

Clarmann Von, Thomas, Birk, Manfred, Bovensmann, Heinrich, Bracher, Astrid, Burgess, Alastair, Cecherini, Simone, ...

The Michelson Interferometer for Passive Atmospheric Sounding (MIPAS), which is a core instrument of the Envisat polar platform launched on 1 March 2002 by the European Space Agency (ESA), is a...

A blind test retrieval experiment for infrared limb emission spectrometry (2003)

Clarmann Von, Thomas, Ceccherini, Simone, Doicu, Adrian, Dudhia, Anu, Funke, Bernd, Grabowski, U., ...

The functionality and characteristics of six different data processors (i.e., retrieval codes in their actual software and hardware environment) for analysis of high-resolution limb emission infrared...

Retrieval of Heavy Molecule Profiles from MIPAS Data Using a Multi-Scale Approach (2003)

Schwarz, Gottfried, Hilgers, Siegfried

Zum Retrieval von Profilen schwerer Moleküle aus MIPAS-Daten bietet sich ein Multi-Skalen-Ansatz an.

Cost/Performance Comparisons of Joint Temperature and Water Vapour Retrievals from MIPAS Data (2003)

Hilgers, Siegfried, Schwarz, Gottfried

Mehrere Alternativen bieten sich für ein gemeinsames Retrieval von Temperatur und Wasserdampfprofilen aus MIPAS-Daten an. Diese werden verglichen.

Sequential and Joint Retrieval of Trace Gas Profiles (2002)

Schwarz, Gottfried, Hilgers, Siegfried, Kemnitzer, Holger, Steck, Tilman, Clarmann Von, Thomas, Höpfner, Michael, ...

A purely sequential retrieval of trace gas profiles from limb sounding measurements may lead to error propagation, especially in the case of water vapor retrieval. A joint (i.e. simultaneous)...

Experiments with Height-Dependent Parameterizations for Limb Profile Retrievals (2002)

Schwarz, Gottfried, Hilgers, Siegfried

The retrieval of vertical trace gas profiles from limb sounding measurements offers the chance for a number of height-dependent parameterizations. Among them basis functions can be used for the...

Stepwise Adaptation of Retrieval Vectors for Limb Profile Retrievals (2002)

Hilgers, Siegfried, Schwarz, Gottfried

The retrieval of vertical trace gas profiles from limb sounding measurements can be accelerated considerably if the usual iterations will be computed with a minimum number of parameters. The...

Trace Gas Retrieval Including Horizontal Gradients (2002)

Kemnitzer, Holger, Hilgers, Siegfried, Schwarz, Gottfried, Steck, Tilman, Clarmann Von, Thomas, Höpfner, Michael, ...

Der Einfluss horizontaler Gradienten auf das Retrieval von Vertikalprofilen wird demonstriert und analysiert.

Advanced MIPAS Level 2 Data Processing (AMIL2DA) (2001)

Clarmann Von, Thomas, Hilgers, Siegfried, Schreier, Franz, Schwarz, Gottfried

First results of the AMIL2DA project show that various processors available for the retrieval of special constituents from MIPAS data deliver comparable results. Remaing differences are mainly due to...

Experience Gained with the MIPAS Level 2 Off-Line Processor (2001)

Hilgers, Siegfried, Kemnitzer, Holger, Ressel, Klaus, Schwarz, Gottfried, Steck, Tilman, Clarmann Von, Thomas, ...

Performance tests of the MIPAS level 2 off-line processor led to in-depth experiences with retrieval options and performance characteristics. These depend on various parameters like microwindows,...

Modelling of the Attainable Resolution of Vertical Details from Limb Sounding Observations (2001)

Schwarz, Gottfried, Hilgers, Siegfried, Kemnitzer, Holger

The presentation compares the attainable vertical resolution (i.e. resolution of vertical details) of atmospheric trace gas profiles obtained by modelling of limb sounding observations. In essence, a...

Use of Selected Initial Guesses for the Retrieval of Trace Gas Profiles (2001)

Schwarz, Gottfried, Hilgers, Siegfried

As a rule, the retrieval of trace gas profiles from atmospheric data sets is based on iterative methods. These iterative methods require initial guess profiles. Simulations showed that tropopause...

Impact of Alternative Matrix Structures on Retrieved Trace Gas Profiles (2001)

Hilgers, Siegfried, Schwarz, Gottfried, Drescher, Armin

We demonstrate how an adaptation of the retrieval vector can be used to reduce memory consumption and run time during the retrieval of trace gas profiles. At the same time. a clever selection of the...

Trace Gas Retrieval Including Horizontal Gradients (2000)

Kemnitzer, Holger, Hilgers, Siegfried, Schwarz, Gottfried, Steck, Tilman, Clarmann Von, Thomas, Höpfner, Michael, ...

The results of trace gas retrievals of limb sounding measurements will be affected by a horizontally inhomogeneous atmosphere. In this case, the horizontal gradients should be included in the...

Sequential and Joint Retrieval of Trace Gas Profiles (2000)

Schwarz, Gottfried, Hilgers, Siegfried, Kemnitzer, Holger, Steck, Tilman, Clarmann Von, Thomas, Höpfner, Michael, ...

We demonstrate that a joint (i.e. simultaneous) retrieval of atmospherical trace gases from limb sounding measurements can outperform a purely sequential retrieval of the same trace gases. The reason...

Tools for the Analysis of Residual Spectra Affecting MIPAS Level 2 Products (2000)

Hilgers, Siegfried, Kemnitzer, Holger, Schwarz, Gottfried, Clarmann Von, Thomas, Milz, Mathias

The use of various automated tools was shown that allow the identification and quantitative analysis of residual spectra resulting after a retrieval of trace gas profiles. The tools include...

Experience Gained with the MIPAS Level 2 Off-Line Processor (2000)

Hilgers, Siegfried, Kemnitzer, Holger, Ressel, Klaus, Schwarz, Gottfried, Steck, Tilman, Clarmann Von, Thomas, ...

The experience gained with the MIPAS level 2 offline processor will be described. In particular, the layout of the processor will be explained and results for various trace gas retrievals will be...

Experience Gained with the MIPAS Level 2 Off-Line Processor (2000)

Hilgers, Siegfried, Kemnitzer, Holger, Ressel, Klaus, Schwarz, Gottfried, Steck, Tilman

An overview of important results originating from the development of the MIPAS level 2 off-line processor will be given. These results include software design aspects, algorithmic details,...