PDS_VERSION_ID = PDS3 RECORD_BYTES = 80 RELEASE_ID = 0001 REVISION_ID = 0000 OBJECT = TEXT INTERCHANGE_FORMAT = ASCII PUBLICATION_DATE = 2024-06-05 NOTE = "N/A" END_OBJECT = TEXT END MARS Express LEGACY ARCHIVE VOLUME 1. Overview This volume contains High Level Data Products, derived from observations acquired by the Observatoire pour la Mineralogie, l'Eau, les Glaces et l'Activite (OMEGA) instrument on Mars Express (MEX). The extraction, description and analysis of these products are detailed in the articles of Szantai et al. (2021) and Olsen et al. (2021). They are representative of the Martian water ice cloud climatology. The 5 retrieved products are 4-dimensional arrays (with axes in longitude, latitude, solar longitude (Ls) and local time (LT)) representing or related to water ice cloudiness: 1) The Reversed Ice Cloud Index (ICIR) 2) The absolute error of the Ice Cloud Index (ERR_ICI) 3) The integrated Water Ice Column (WIC) 4) The Percentage of Cloudy Pixels (PCP) 5) The Number of Orbits (NB_ORB) The central product is the ICIR. Initially the Ice Cloud Index (ICI) is defined as the depth of an IR absorption band of water ice at 3.4 um that is derived from the original OMEGA (L1) data cubes. ICI values have been extracted for all valid pixels of OMEGA orbits between 14-Jan-2004 and 27-Apr-2014, then binned and averaged over the 4-dimensional spatio-temporal grid. The Reversed Ice Cloud Index (ICIR) is defined by the following relation : ICIR = 1 - ICI The integrated Water Ice Column (WIC) is related by a linear relation to the ICI and thus has been directly derived from the ICI (Olsen et al., 2021). A threshold has been defined in order to determine if an ICI pixel value from the original OMEGA data is cloudy or non-cloudy. For each 4-dimensional spatio-temporal gridpoint, the ratio of cloudy pixels to cloudy + non-cloudy pixels defines the Percentage of Cloudy Pixels (PCP). Each 4-dimensional gridpoint has been covered by one or several orbits - or not at all. Note that this Number of Orbits (NB_ORB) is 0 for a majority of gridpoints. Thus the NB_ORB variable can be used as a mask indicating missing data. DATA_SET_ID : MEX-M-OMEGA-5-DDR-H2OCLOUDS-MAPS-V1.0 ----------- CONTENTS DESCRIPTION : 4-dimensional (spatio-temporal) climatological data -------------------- representative of water ice clouds derived from OMEGA IR absorption bands at 3.4 um. Data products archived in this volume are reformatted versions of the original IDL files calculated and provided by Andre Szantai, the corresponding author of Szantai et al. 2021. Based on the description of Olsen et al. 2021, the Water Ice Column product has also been calculated and added by A. Szantai to this archive. The reformatting has been checked by MEX Interdisciplinary scientist (IDS) Anni Määttänen. Future errors and anomalies in the data and comments the archive will be noted in the ERRATA.TXT file. 2. Archive Volume - Concept of Delivery Within the Planetary Science Archive (PSA) the archive volume represents an online delivery. This might be not fully compliant with the PDS standard 3.6, but the PSA itself can after the end of mission produce fully compatible archive volumes. Deliveries are based on the concept of a release and a revision. This concept allows the delivery of experiment data without the delivery of all supplementary information, that has already been delivered at the first initial delivery of a fully PDS compatible Archive Volume, containing the VOLDESC.CAT file and all necessary CATALOG, DOCUMENT, INDEX, DATA, etc directories and their content. A data set release (or volume release) contains data from a well-defined period of time and is identified by the RELEASE_ID (4 digit number : [0001:9999]). A volume release is made of at least one revision : the initial revision. The initial revision contains the initial data of a data set release and is identified by a REVISION_ID equal to 0000. A following revision of the data set release (updated files, supplementary files, deleted files) would need the value of the REVISION_ID incremented by one. A release catalog object needs to be included in the catalog object to fully describe the release. The release object contains all keyword-value pairs that are necessary to identify a revision within a release. The DESCRIPTION part of the DATA_SET_RELEASE object will contain the full history of the release including all previous revisions. Each revision of a release is added in the release catalog object and all necessary information about this revision is given by a REVISION object. 3. File Formats This section provides a brief description of the files and data objects available on this MEX Legacy Archive volume: text files, PDF files, FITS files, and PDS objects. A complete description of each file format is available in the DOCUMENT/EAICD text on the archive volume. Text and detached PDS label files have stream or fixed-length record format, and line lengths of obligatory 80 characters, including a carriage return (ASCII 13) at the end of the record. This allows the files to be read by MS-DOS/Windows,Unix, and VMS operating systems. Documents that contain formatting and figures that cannot be rendered as ASCII text are provided as PDF files. The PDF (Portable Document Format) file is a proprietary format of Adobe Systems Incorporated that can be viewed using the free Acrobat Reader software. The FITS (Flexible Image Transport System) format describes astronomical and other scientific data. It has been defined and described in Hamish et al. 2001, in 'Astronomy and Astrophysics', vol. 376, pp. 359-380; doi: 10.1051/0004-6361:20010923 . Each FITS file in this dataset contains a 4-dimensional data array, the description of its encoding and content, and complementary data (dimensions and axes). A PDS detached label provides descriptive information about the associated file. Most of the PDS labels in this Data Archive conform to PDS standards [Planetary Science Data Dictionary, 2001; PDS Standards Reference, 2003]. For examples of the PDS labels used with each type of data product, see the DOCUMENT/SA_MEX_ARCH_003_xx.PDF (or .ASC) text on the archive volume. In general, the PDS label is an object-oriented structure consisting of sets of 'keyword = value' declarations; the object to which the label refers is denoted by a statement of the form: ^object = location in which the carat character (^, also called a pointer in this context) indicates where to find the object. In a detached label, the location denotes the name of the file containing the object, along with the starting record or byte number, if there is more than one object in the file. For example: ^HEADER = ("F01.DAT",1) ^IMAGE = ("F01.DAT",1025 ) indicates that the IMAGE object begins at byte 1025 of the file F01.DAT, in the same directory as the detached label file. 4. Science Utilisation The MEX Legacy Archive publishes high-level products derived from the MEX data. The archived high-level datasets have been published in peer-reviewed scientific articles. The references to the publications are given in the documentation of the data volume. The archiving in the MEX Legacy Archive has been made with the consent of the corresponding author and the PI of the instrument. 5. File Naming Convention In this data volume, the data products have been named with the following convention: MEX_OMEGA_ttttttt_Vv.FIT where ttttttt 3 to 7 letters, or underscore, describing the data type v version number of the file The corresponding label files have the same file name convention, with a .LBL extension instead of .FIT . 6. Applicable Software No software is provided in this data volume. 7. Volume Contents Files on this archive volume are organized into a series of subdirectories below the top-level directory, as required by the PSA. See the xxxxINFO.TXT files in each directory for specific information on the files in the directory. The following table shows the generalized structure and contents of this archive volume. Top-level ROOT | |- AAREADME.TXT The file you are reading | |- ERRATA.TXT Description of known anomalies and errors present | on the volume. |- VOLDESC.CAT Description of the contents of the volume in a PDS | format for the PDS Catalog. | | |- [DATA] A directory containing the data + associated label files | | | |-- {file(s) *FIT, *.LBL} | | | ... | |- [CATALOG] A directory containing information about the data set | | | |- CATINFO.TXT Description of files in this directory | | | |- DATASET.CAT Description of the MEX Legacy Archive | | Szantai et al. 2024 dataset. | | | |- RELEASE.CAT Release object of the Legacy Archive | | Szantai et al. 2024 dataset. | | | | | |- MISSION.CAT Description of the Mars Express mission | | | |- INSTHOST.CAT Description of the Mars Express spacecraft | | | |- INST.CAT Description of the MEX SPICAM instrument | | | |- PERS.CAT Listing of the people involved in the | | production of this archive volume | |- REFS.CAT List of pertinent references. | | | |- SOFTWARE.CAT Description of the software included on the | | volume. | |- [DOCUMENT] A directory containing information documents. | | | |- DOCINFO.TXT Description of files in this directory. | | | |- SZANTAI_ET_AL_2021.PDF PDF document of the peer-reviewed | | article describing the main part of | | the dataset. | |- SZANTAI_ET_AL_2021.LBL PDS detached label file that describes | | SZANTAI_ET_AL_2021.PDF | |- OLSEN_ET_AL_2021.PDF PDF document of the peer-reviewed | | article with the method used to create | | the rest of the dataset (Water Ice | | Column) | |- OLSEN_ET_AL_2021.LBL PDS detached label file that describes | | OLSEN_ET_AL_2021.PDF | | 8. Whom to Contact for Information For questions concerning this data set: Contact ANNI MAATTANEN (MEX IDS) GAETAN LACOMBE (Project Manager) or LESTER DAVID (Archive Manager) For questions concerning OMEGA, contact J. CARTER or J.P. BIBRING (OMEGA PI). See personnel information in PERS.CAT catalog. 9. Cognizant Persons The archived data were provided by A. Szantai.