DESCRIPTION = "This file describes the format of the TABLE in the GVADF.TAB file. See the GVADF.LBL file for the full PDS label." OBJECT = COLUMN NAME = SAMPLE_COUNT DATA_TYPE = MSB_UNSIGNED_INTEGER START_BYTE = 1 BYTES = 2 DESCRIPTION = "The total number of ARCDRCD ADF footprints used to compute the estimates of radar scattering properties given in this row of the table. The quantities given in later columns pertain only these footprints. Any altimetry footprint that is partially or completely contained inside this pixel is included. (Only the small inner portion of altimetry footprints is considered for inclusion; this is the portion described by the ARCDRCD ADF fields ALT_ALONG_TRACK_FOOTPRINT_SIZE (alias AR_XFOOT) and ALT_CROSS_TRACK_FOOTPRINT_SIZE (alias AR_YFOOT). This does not include altimetry footprints that illuminated this pixel but did not do so from directly above.)" END_OBJECT = COLUMN OBJECT = COLUMN NAME = RADIUS_MEAN DATA_TYPE = MSB_UNSIGNED_INTEGER START_BYTE = 3 BYTES = 2 OFFSET = 6040 SCALING_FACTOR = 0.000457806 UNIT = KM VALID_MINIMUM = 6040 VALID_MAXIMUM = 6070 DESCRIPTION = "The mean planetary radius of all the footprints used in this row. The radius is obtained from the DERIVED_PLANETARY_RADIUS field (alias AR_RADIUS) in the ARCDRCD." END_OBJECT = COLUMN OBJECT = COLUMN NAME = RADIUS_VARIANCE DATA_TYPE = MSB_UNSIGNED_INTEGER START_BYTE = 5 BYTES = 2 OFFSET = 0 SCALING_FACTOR = 7.63009e-05 UNIT = KM_SQUARED VALID_MINIMUM = 0 VALID_MAXIMUM = 5 DESCRIPTION = "The unbiased estimate of the variance of the planetary radius of all of the footprints used in this row. The radius is obtained from the DERIVED_PLANETARY_RADIUS field (alias AR_RADIUS) in the ARCDRCD. The variance estimate gives an indication of the topographic relief across the pixel. The unbiased estimate is obtained from the following formula: RADIUS_VARIANCE = 1/(N-1) * ( SUM(X_i^2) - 1/N * [SUM(X_i)]^2 ) where N = SAMPLE_COUNT above X_i = samples of radius AR_RADIUS, i = 1,2,...,N." END_OBJECT = COLUMN OBJECT = COLUMN NAME = SLOPE_MEAN DATA_TYPE = MSB_UNSIGNED_INTEGER START_BYTE = 7 BYTES = 1 OFFSET = 0 SCALING_FACTOR = 0.06 UNIT = DEGREE VALID_MINIMUM = 0 VALID_MAXIMUM = 15 DESCRIPTION = "The mean surface rms slope of the footprints used in this row. The rms slope is obtained from the RADAR_DERIVED_SURF_ROUGHNESS field (alias AR_SLOPE) in the ARCDRCD, and is based on the Hagfors model of rough surface scattering." END_OBJECT = COLUMN OBJECT = COLUMN NAME = SLOPE_VARIANCE DATA_TYPE = MSB_UNSIGNED_INTEGER START_BYTE = 8 BYTES = 1 OFFSET = -3 SCALING_FACTOR = 0.02 UNIT = "N/A" /* see DESCRIPTION */ VALID_MINIMUM = 0.001 VALID_MAXIMUM = 100 DESCRIPTION = "The unbiased estimate of the variance of the rms slope of all of the footprints used in this row. The rms slope is obtained from the RADAR_DERIVED_SURF_ROUGHNESS field (alias AR_SLOPE) in the ARCDRCD, and is based on the Hagfors model of rough surface scattering. The variance estimate gives an indication of the surface roughness variability across the pixel. The unbiased estimate is obtained from the following formula: SLOPE_VARIANCE = 1/(N-1) * ( SUM(X_i^2) - 1/N * [SUM(X_i)]^2 ) where N = SAMPLE_COUNT above X_i = samples of slope AR_SLOPE, i = 1,2,...,N. The units of this measurement are degrees-squared, but the value stored in the table is the base-10 logarithm of the true value. To obtain the true value, apply the scaling and offset given above and raise 10 to this power." END_OBJECT = COLUMN OBJECT = COLUMN NAME = REFLECTIVITY_MEAN DATA_TYPE = MSB_UNSIGNED_INTEGER START_BYTE = 9 BYTES = 1 OFFSET = -2.5 SCALING_FACTOR = 0.01 UNIT = "N/A" /* see DESCRIPTION */ VALID_MINIMUM = 0.00316228 VALID_MAXIMUM = 1 DESCRIPTION = "The mean surface bulk reflectivity of the footprints used in this row. The bulk reflectivity is obtained from the DERIVED_FRESNEL_REFLECTIVITY field (alias AR_RHO) in the ARCDRCD, and is based on the Hagfors model of rough surface scattering. The value has not been adjusted by the diffuse scattering correction term DERIVED_FRESNEL_REFLECT_CORR (alias AR_RHOCOR). The units of this measurement are dimensionless, but the value stored in the table is the base-10 logarithm of the true value. To obtain the true value, apply the scaling and offset given above and raise 10 to this power." END_OBJECT = COLUMN OBJECT = COLUMN NAME = REFLECTIVITY_VARIANCE DATA_TYPE = MSB_UNSIGNED_INTEGER START_BYTE = 10 BYTES = 1 OFFSET = -7 SCALING_FACTOR = 0.028 UNIT = "N/A" /* see DESCRIPTION */ VALID_MINIMUM = 0.000000100 VALID_MAXIMUM = 1 DESCRIPTION = "The unbiased estimate of the variance of the surface bulk reflectivity of the footprints used in this row. The bulk reflectivity is obtained from the DERIVED_FRESNEL_REFLECTIVITY field (alias AR_RHO) in the ARCDRCD, and is based on the Hagfors model of rough surface scattering. The value has not been corrected with the diffuse scattering correction term DERIVED_FRESNEL_REFLECT_CORR (alias AR_RHOCOR). The variance estimate gives an indication of the surface reflectivity variability across the pixel. The unbiased estimate is obtained from the following formula: REFLECTIVITY_VARIANCE = 1/(N-1) * ( SUM(X_i^2) - 1/N * [SUM(X_i)]^2 ) where N = SAMPLE_COUNT above X_i = samples of slope AR_RHO, i = 1,2,...,N. The units of this measurement are dimensionless, but the value stored in the table is the base-10 logarithm of the true value. To obtain the true value, apply the scaling and offset given above and raise 10 to this power." END_OBJECT = COLUMN