Data Set Information
DATA_SET_NAME MGN V RDRS 5 GLOBAL DATA RECORD EMISSIVITY V1.0
DATA_SET_ID MGN-V-RDRS-5-GDR-EMISSIVITY-V1.0
NSSDC_DATA_SET_ID
DATA_SET_TERSE_DESCRIPTION
DATA_SET_DESCRIPTION Data Set Overview : Global Emissivity Data Record (GEDR). The emissivity of a surface is defined as the thermal power emitted by that surface divided by the power emitted by a black body of the same size and at the same physical temperature. The polarization direction is horizontal (E-field tangential to surface), and the emissivity is not corrected for emission angle or surface roughness or tilt. This data set includes all Magellan measurements in which the high-gain antenna followed the nominal look-angle profile, in which the observed emission angle varied from 48 degrees off the local vertical at periapsis (ca. 10N latitude) to 15 degrees off vertical at the 90N and 70S. To make the GEDR images, Magellan radiometer data, in the form of readings of antenna noise temperature, are corrected for antenna sidelobe effects and for emission and absorption by the Venus atmosphere. The component reflected from the surface is modeled as a specular reflection with power reflection coefficient equal to (1 - emissivity). The location and planetary radius at the antenna boresight intercept point are derived from GTDR images and the physical surface temperature is calculated using the adiabatic model of Kliore et al., 1985. The data are then filtered to remove low-frequency instrument calibration errors, and re-sampled into sinusoidal, Mercator, and north and south polar stereographic projections at a resolution of about 5x5 kilometers per pixel. Each GEDR image pixel is represented by a 16-bit integer. In sinusoidal images, pixels lying outside the domain of the projection are set to zero. In all images, pixels with unknown or unmeasured values are also set to zero. The remaining values are related to the emissivity by the following equation: DN : (EMISSIVITY * 10000) + 1. See: Software Interface Specification Document (Peter G. Ford, 1991, Global Altimetry and Radiometry Data Records, MIT-MGN-GxDR SIS Version 2.3, 40 p.) that is included on GxDR CD-ROMs. Note: There exist photoproducts that are identified as GxDRP (where x is E (Emissivity), S (Slope), RE (Reflectivity), or T (Topography)) however, they are not generated from the digital GxDR products. They are instead produced from the Magellan ARCDR (Altimetry and Radiometry Composite Data Record) data files. Parameters : Data Set Parameter 'EMISSIVITY' ------------------------------- Emissivity is the ratio of radiance received from a target, at a given kinetic temperature, to the radiance received fro a blackbody at the same temperature. Data Set Parameter Name : EMISSIVITY Data Set Parameter Unit : DIMENSIONLESS Sampling Parameter Name : PIXEL Sampling Parameter Unit : METER Minimum Sampling Parameter : N/A Maximum Sampling Parameter : N/A Sampling Parameter Resolution : 9282 Sampling Parameter Interval : 4641 Minimum Available Sampling Int : N/A Noise Level : UNK Source Instrument Parameters : Instrument Host ID : MGN Data Set Parameter Name : EMISSIVITY Instrument Parameter Name : RADIANT POWER Important Instrument Parameters : 1 Processing : Processing History ------------------ Source Data Set ID : MGN-V-RDRS-5-CDR-ALT/RAD-V1.0 Software : MGMMAP Product Data Set ID : MGN-V-RDRS-5-GDR-EMISSIVITY-V1.0 Software 'MGMMAP' ----------------- The MIT Altimetry and Radiometry Mapping Software (MGMMAP) reads Altimetry and Radiometry Composite Data Records (ARCDRs), and generates an image of a specified data field i a specified map projection. Each footprint datum is added with a weight and horizontal extent proportional to the appropriate ARCDR elements. This software will be released t Magellan Data Management Archive Team (DMAT) upon the completion of the nominal mission. Software Name : MGMMAP Software Type : N/A Software Release Date : N/A Node ID : N/A Cognizant Engineer : DR. PETER G. FORD Software Access Description : N/A
DATA_SET_RELEASE_DATE 1992-01-15T00:00:00.000Z
START_TIME 1990-09-15T04:22:15.591Z
STOP_TIME 1992-09-14T02:27:38.204Z
MISSION_NAME MAGELLAN
MISSION_START_DATE 1989-05-04T12:00:00.000Z
MISSION_STOP_DATE 1994-10-12T12:00:00.000Z
TARGET_NAME VENUS
TARGET_TYPE PLANET
INSTRUMENT_HOST_ID MGN
INSTRUMENT_NAME RADAR SYSTEM
INSTRUMENT_ID RDRS
INSTRUMENT_TYPE RADAR
NODE_NAME Geosciences
ARCHIVE_STATUS ARCHIVED
CONFIDENCE_LEVEL_NOTE Overview : UNK
CITATION_DESCRIPTION Ford, P. G., MGN V RDRS 5 GLOBAL DATA RECORD EMISSIVITY V1.0, MGN-V-RDRS-5-GDR-EMISSIVITY-V1.0, NASA Planetary Data System, 1992
ABSTRACT_TEXT This data set contains the Magellan Global Emissivity Data Record (GEDR). The emissivity of a surface is defined as the thermal power emitted by that surface divided by the power emitted by a black body of the same size and at the same physical temperature.
PRODUCER_FULL_NAME PETER G. FORD
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