QDOAS_Presentation_20071203_Updated_20080905

1、QDOAS introduction BIRA-IASB, 3 December 2007QDOAS a cross-platform implementation of WinDOAS Caroline Fayt, caroline.faytaeronomie.beMichel van Roozendael Jos van GeffenBelgian Institute for Space Aeronomy (BIRA/IASB)Ian Price, pricescience-and-technology.nl Sander NiemeijerScience and technology (

2、S&T)QDOAS introduction BIRA-IASB, 3 December 2007WinDOAS history1990 : DOS version of a CNRS HP-Basic program1997 : first Windows version, one year development 1998 : consolidate the software, first users1999 : version for GOME2001 : issue of a stable version, documentation, help2002 : include S

3、CIAMACHY format2004 : first Linux version (no user interface)2007 : version for GOME2 2007/2008 : development of a cross-platform GUIQDOAS introduction BIRA-IASB, 3 December 2007WinDOAS definition First developed for BIRA-IASB DOAS activities; Not static, in continuous development; The result of mor

4、e than 17 years of expertise in DOAS retrieval from ground-based and satellites measurements; Validated through different campaigns; A program that combines some powerful DOAS tools and a friendly user interface; A success story : largely used worldwide and for many different DOAS applications (grou

5、nd-based, satellites, balloons, long-path);QDOAS introduction BIRA-IASB, 3 December 2007DOAS features (1/2) Decomposition of the DOAS equation into a linear and a non linear least-squares fitting problems; Possibility to define several spectral fitting windows; Shift and squeeze for any spectral ite

6、m; Possibility to fix the concentration of any species; Possibility to filter spectra and cross sections; Possibility to correct for an instrumental offset; Polynomial until order 5 to fit the continuous part; Differential cross sections (using orthogonalisation or high-pass filtering); Automatic se

7、lection of the reference spectrum;QDOAS introduction BIRA-IASB, 3 December 2007DOAS features (2/2) Characterization of the wavelength calibration and the slit function of the instrument using a NLLS fitting approach where the measured intensities are fitted to a high-resolution solar spectrum degrad

8、ed to the resolution of the instrument; several analytical slit function supported. Cross sections can be convoluted using the information retrieved at the previous step; Powerful convolution tool (standard convolution and I0-corrected, different supported line shapes, possibility to account for a w

9、avelength dependence of the resolution); Ring/Undersampling tools;QDOAS introduction BIRA-IASB, 3 December 2007The WinDOAS user interfaceQDOAS introduction BIRA-IASB, 3 December 2007The WinDOAS user interface Friendly user interface with projects and analysis windows organized in trees; Options are

10、distributed in tab pages; Possibility to display the result of the fit; Step by step, possibility to move easily in the file; Possibility to zoom in graphs; Possibility to disable the user interface and to load the program from the command line; According to the format of files, some specific implem

11、entations to manage files; possibility to include folders; Output fully configurable.QDOAS introduction BIRA-IASB, 3 December 2007QDOAS definition Joint collaboration with S&T, a Dutch company already well-known for the development of cross-platform products and software tools for the processing

12、 of satellites measurements. QDOAS is a cross-platform implementation of WinDOAS i.e. Qdoas is portable to Windows, Unix/Linux and Mac, and the user interface is effectively the same on all platforms The GUI is built on the Open-Source version of the QT-4 toolkit, a cross-platform application framew

13、ork (http:/), and QWT plot librariesQDOAS introduction BIRA-IASB, 3 December 2007QDOAS : the user interfaceQDOAS introduction BIRA-IASB, 3 December 2007QDOAS vs WinDOAS : overviewMajor improvements :Better separation of the code between the user interface (GUI) and the engine The main sub-components

14、 of the GUI into resizable panels with a fixed arrangementMulti-page organization with tab-switched access for project/analysis windows settings and plotted results.Configuration of plot colour and styleConfiguration file in XML format (specific editors)A true management of spectra files in the proj

15、ect treeQDOAS introduction BIRA-IASB, 3 December 2007EngineMediatorGUIGUIMediatorEngineQDOASWinDOASQDOAS vs WinDOAS : CodeQDOAS introduction BIRA-IASB, 3 December 2007Main changes :All the spectral windows processed in one shotExport in different portable image formats (png, jpg)New plot options (th

16、e scaling of the plot)Overlay of an existing ASCII file (to test)Known problems :Gaps and zero values in the plotQDOAS vs WinDOAS : ProcessingQDOAS introduction BIRA-IASB, 3 December 2007QDOAS : project propertiesQDOAS introduction BIRA-IASB, 3 December 2007Main changes :File formats are distributed

17、 in two groups : ground-based (16) and satellites (5)Files in alphabetic orderFile format selection out of the instrument pageIn order to constrain the selection of fields to display and results to outputNot yet operational :Satellites : OMI, GOME-ASCII not yet supportedUndersampling pagesMinor chan

18、ges :Units for shift and stretch : nm onlyNASA-AMES page doesnt exist anymoreQDOAS vs WinDOAS : projectsQDOAS introduction BIRA-IASB, 3 December 2007QDOAS : AW propertiesQDOAS introduction BIRA-IASB, 3 December 2007Minor changes :Horizontal scrollingShift and stretch in nm units only Hidden option in WinDOAS (expert mode) : concentration of a molecule constrained to the value found in a previous windowUse of AMF files to calculate vertical columns Be