PDS_VERSION_ID = PDS3 RECORD_TYPE = FIXED_LENGTH RECORD_BYTES = 80 OBJECT = TEXT INTERCHANGE_FORMAT = ASCII PUBLICATION_DATE = 2008-05-09 NOTE = "N/A" END_OBJECT = TEXT END Mars Global Surveyor Radio Science Team Electron Density Profile Archive (MGS-M-RSS-5-EDS-V1.0) AAREADME.TXT R.A. Simpson Stanford University ============================================================================== OVERVIEW ============================================================================== This archival volume contains the entire collection of radio occultation ionospheric electron density (EDS) profiles derived from Mars Global Surveyor (MGS) data during the MGS mission. The profiles were archived previously as part of the MGS-M-RSS-5-SDP-V1.0 data set (38 volumes, from MORS_1001 through MORS_1038). These are the same profiles, but they have been collected into a single volume where they are organized chronologically. The accompanying PDS detached labels are also the same except for minor edits needed for conformance to the new data set. ============================================================================== VOLUME STRUCTURE ============================================================================== The volume has three files and five directories at the root level. The AAREADME.TXT file (this file) provides an overview of the archive; the ERRATA.TXT file contains notes, warnings, and known errors in the data set at the time the volume was produced; and the VOLDESC.CAT file contains catalog information. Each file is ASCII with lines of 80 characters, the last two in each line being the ASCII carriage-return and line-feed. The EDS directory contains 12 subdirectories with names of the form yyyy_ddd giving the year (yyyy) and day-of-year (ddd) of the first electron density file within. The subdirectory coverage does not overlap and there are often days or weeks between the last file in one directory and the first file in the next. The OCS directory contains a single file which is a summary table of all 5600 electron density profiles (the slightly edited header record from each EDS file). Each entry in the table gives the latitude and longitude of the occultation point, the solar longitude (Ls) of Mars, the solar zenith angle, the local true solar time, names of files used in the processing, and the name of the parent EDS file. In the INDEX directory the INDEX.TAB file contains path information to each data file in the volume as well as start time and stop time for the data and the date/time at which the data file was created. The CATALOG directory contains more cataloging information. Included are files describing the mission, instrument, and data set. The DOCUMENT directory contains more specific information on the file organization and structure. Included is a Software Interface Specification (SIS) document, describing the organization of the volume and and its files. Also included is the OCCLOG.TAB file, which is a summary of each observation opportunity with equipment settings from data acquisition and results from early processing. This table has 33888 rows, including summaries of tests and failed observation attempts. The diagram below shows the organization of this volume, starting from the root of the compact disc. root | |- AAREADME.TXT |- ERRATA.TXT |- VOLDESC.CAT | |- CATALOG | | | |- CATINFO.TXT Streamlined PDS catalog files | |- MISSION.CAT for mission, host, instrument, | |- INSTHOST.CAT references, personnel, data | |- INST.CAT set, and target. | |- REF.CAT | |- PERSON.CAT | |- DATASET.CAT | `- TARGET.CAT | |- DOCUMENT | | | |- DOCINFO.TXT Overview of directory | |- OCCLOG.TAB Summary of observation attempts | |- OCCLOG.LBL PDS label for OCCLOG.TAB | `- EDS_VOLM.TXT SIS for the volume | |- INDEX | | | |- INDXINFO.TXT Overview of directory | |- INDEX.LBL Label to INDEX.TAB | `- INDEX.TAB Table of contents for this volume | | | DATA DIRECTORIES | |- OCS Occultation Summary File | | | |- 812506AA.OCS Summary of EDS files | `- 812506AA.LBL PDS label for above | `- EDS Electron Density Profiles | |- yyyy_ddd Directory containing EDS files starting | | on year yyyy and day ddd | | | |- ydddHmmN.EDS Nth solution for data beginning year y, | |- ydddHmmN.LBL day ddd, hour H, minute mm; PDS label | |- ... (repeated for other profiles) | `- ... ... | |- yyyy_ddd Other directories and files | ... To locate specific data files within the volume, users should consult INDEX.TAB in the INDEX directory. To search for occultations captured under certain conditions (solar zenith angle, latitude, season, etc.) users should sort the 812506AA.OCS file in the OCS directory. To find occultations meeting certain signal-to-noise ratio or observing criteria, sorting the OCCLOG.TAB files in the DOCUMENT directory may be the most appropriate strategy. ============================================================================== ERRATA ============================================================================== A cumulative list of notes, warnings, and known errors is maintained in the ERRATA.TXT file at the root level of each volume. ERRATA.TXT in the initial release of this volume will have little content, however. ============================================================================== FILE FORMAT ============================================================================== All data files on the disc are accompanied by detached PDS labels, which describe their contents. PDS TEXT objects have attached labels. Detached labels have the same file name as the data file except that the label name has the suffix "LBL". The label fully describes the format and content of its associated file. Detached labels use pointers to reference the data file -- for example, ^IMAGE = "JGM50C01.IMG" points to JGM50C01.IMG, which contains the actual image described by the label. Some data files contain more than one structure. For example, ^RSED_HDR_TABLE = ("8358D47A.EDS",1) ^RSED_TABLE = ("8358D47A.EDS",6) are pointers to the file 8358D47A.EDS which contains two tables, one beginning at record 1 and one beginning at record 6. Additional documentation on all data file types is available in the Volume Software Interface Specification in the DOCUMENT directory. Text files, including data files of ASCII text and all labels (*.LBL files) and tables (*.TAB files), are delimited with carriage-return (ASCII 13) line-feed (ASCII 10) pairs at the end of each line. In a departure from the practice in the original MGS-M-RSS-5-SDP-V1.0 archive, detached labels generally do NOT have fixed length records (of 80 bytes). This change was instituted to reduce the total volume of the EDS directory. Text and catalog files (*.TXT and *.CAT, respectively) do have fixed length records of 72 or 80 bytes, ending with a carriage-return line-feed pair. ============================================================================== CITATIONS ============================================================================== Users wishing to cite products in this volume should use the following volume information: Author: D.P. Hinson Editor: R.A. Simpson Volume Name: Mars Global Surveyor Radio Occultation Profiles of the Ionosphere - Reorganized Volume: USA_NASA_JPL_MORS_1102 Data Set ID: MGS-M-RSS-5-EDS-V1.0 Publisher: NASA Planetary Data System Year: 2008 ============================================================================== ACKNOWLEDGMENTS ============================================================================== These data were collected under auspices of the Mars Global Surveyor Project. G. Leonard Tyler of Stanford University was the Radio Science Team Leader. Members of the Team and its support elements involved in data acquisition and validation included Patricia Priest, Sami Asmar, Aseel Anabtawi, Elias Barbinis, Paula Eshe, Danny Kahan, Alex Konopliv, Frank Lemoine, William Sjogren, Tim Smith, and Joe Twicken. At PDS the assistance of Ed Guinness, Lyle Huber, Betty Sword, and Joel Wilf was appreciated. ============================================================================== DISCLAIMER ============================================================================== Although considerable care has gone into making this volume set, errors are possible. Reports of errors or difficulties would be appreciated. Please contact one of the persons listed below. ============================================================================== COGNIZANT PERSONNEL ============================================================================== David Hinson was the lead scientist for radio occultation studies on the MGS Radio Science Team and was primarily responsible for extracting the electron density profiles from the raw data; he also reorganized the data for this volume. Dick Simpson, MGS Radio Science Team Experiment Engineer, assembled the volume. G. Leonard Tyler was the Leader of the MGS Radio Science Team. David P. Hinson Center for Radar Astronomy Packard Building - Room 333 350 Serra Mall Stanford University Stanford, CA 94305 Tel: 650-723-3534 FAX: 650-723-9251 dhinson@stanford.edu or David P. Hinson SETI Institute 515 North Whisman Rd Mountain View, CA 94043 Tel: 650-810-0217 dhinson@seti.org Richard A. Simpson Center for Radar Astronomy Packard Building - Room 332 350 Serra Mall Stanford University Stanford, CA 94305 Tel: 650-723-3525 FAX: 650-723-9251 rsimpson@magellan.stanford.edu G. Leonard Tyler Center for Radar Astronomy Packard Building - Room 331 350 Serra Mall Stanford University Stanford, CA 94305 Tel: 650-723-3535 FAX: 650-723-9251 len.tyler@stanford.edu ============================================================================== ACRONYMS AND ABBREVIATIONS ============================================================================== CD Compact Disc HGA High-Gain Antenna MGS Mars Global Surveyor OCS Occultation Summary File (standard resolution products) PDS Planetary Data System RSS Radio Science Subsystem RST Radio Science Team SDP Science Data Products SIS Software Interface Specification T-p Temperature-pressure TPS Temperature-Pressure Profile (standard resolution) WO Write Once