TWP/XSACR/C3 - General Quality Statement

The SACR continues to undergo evaluation by the radar instrument mentors, ProSensing, VAP 
developers, DQ Office, site scientists, users, etc.  As more in-depth analysis and 
calibration studies take place, we anticipate that new insights will be gained to increase the 
quality of the data and decrease the uncertainty of the measurements.  This is a 
continuous improvement process and issues will be addressed as they are discovered.

Calibration is very important.  Calibration of the SACRs depends on the careful 
installation of a corner reflector target.  These are installed at all ARM fixed sites and AMF1 on 
Cape Cod.  This provides a external calibration reference not obtainable with a 
zenith-pointing radar such as the KAZR.  However, significant data analysis is required to assure 
that the radar is pointing at the target and there are no interfering losses in the 
transmission path.

As issues are discovered, attempts will be made to correct data that is currently in the 
Archive.  However, retrospective correction of errors due calibration, signal processing, 
component degradation and software bugs may not be possible for many of the data files.

This open-ended DQR is an advisory that some aspects of the data quality are not yet 
known.  It is also a request for users that find issues or questions with the data to contact 
the ARM Radar Engineering & Operations Group Manager, Kevin Widener, at 
kevin.widener@pnnl.gov as these issues occur so that they can be investigated and corrected if necessary.

• measurements contained in this datastream are unknown

• measurements contained in this datastream are unknown

• Unambiguous range(unambiguous_range)
• Noise flor for vertical cross-polar channel 2(r_calib_noise_vx)
• data_volume_index_number(volume_number)
• Number of samples used to compute moments(n_samples)
• North Latitude(lat)
• transmit_pulse_mode(prt_mode)
• Transmit power(r_calib_xmit_power_h)
• -180.0 - +180.0(alt)
• altitude_above_ground_level(altitude_agl)
• Primary axis of rotation(primary_axis)
• Linear depolarization ratio(linear_depolarization_ratio)
• pulse_repetition_frequency(prt)
• Nominal radar antenna gain, v channel(radar_antenna_gain_v)
• lon(lon)
• reflectivity(reflectivity)
• Mean doppler velocity(mean_doppler_velocity)
• Scan rate, positive for clockwise or increasing elevation(scan_rate)
• platform_type(platform_type)
• ray_target_fixed_angle(fixed_angle)
• Index of first ray in sweep, 0-based(sweep_start_ray_index)
• North latitude(latitude)
• antenna_is_in_transition_between_sweeps(antenna_transition)
• Index for the calibration that applies to each ray(r_calib_index)
• time_in_seconds_since_volume_start(time)
• Pulse width for this calibration(r_calib_pulse_width)
• Signal-to-noise-ratio(snr)
• Nominal radar antenna gain, h channel(radar_antenna_gain_h)
• Unambiguous Doppler velocity(nyquist_velocity)
• Time of the calibration that applies to each ray(r_calib_time)
• Radar beam width, vertical channel(radar_beam_width_v)
• radiation_frequency(frequency)
• Noise power in noise source region for horizontal copolar channel 1(r_calib_noise_source_power_h)
• East longitude(longitude)
• radar_calibration_two_way_radome_loss_h_channel(r_calib_two_way_radome_loss_h)
• Pulse width(pulse_width)
• Time corresponding to last radial in file(time_coverage_end)
• Scan mode for sweep(sweep_mode)
• type_of_instrument(instrument_type)
• Radar measured transmit power, h channel(radar_measured_transmit_power_h)
• calibrated_radar_receiver_gain_v_co_polar_channel(r_calib_receiver_gain_hc)
• Distance to the center of the corresponding range bin(range)
• half_power_radar_beam_width_h_channel(radar_beam_width_h)
• Noise floor power for horizontal copolar channel1(r_calib_noise_hc)
• base time in epoch(base_time)
• Doppler spectrum width (second moment of the doppler spectrum)(spectral_width)
• Radar constant, vertical cross-polar channel 2(r_calib_radar_constant_v)
• Polarization mode(polarization_mode)
• Azimuth of Radar Ray(azimuth)
• data_volume_start_time_utc(time_coverage_start)
• Radar constant, horizontal copolar channel 1(r_calib_radar_constant_h)
• Sweep number, zero-based count(sweep_number)
• altitude(altitude)
• Beam Elevation Angle(elevation)
• Noise power in noise source region for vertical cross-polar channel(r_calib_noise_source_power_v)
• Time index of last ray in sweep, 0-based(sweep_end_ray_index)
• Receiver gain for vertical cross-polar channel 2(r_calib_receiver_gain_vx)
• Follow mode(follow_mode)

• Mean doppler velocity(mean_doppler_velocity)
• North Latitude(lat)
• -180.0 - +180.0(alt)
• Time offset from base_time(time_offset)
• Spectra(spectra)
• time_in_seconds_since_volume_start(time)
• Doppler spectrum width (second moment of the doppler spectrum)(spectral_width)
• base time in epoch(base_time)
• Spectral velocity bins(velocity_bins)
• Beam Elevation Angle(elevation)
• reflectivity(reflectivity)
• lon(lon)
• Distance to the center of the corresponding range bin(range)
• Locator Mask for Spectra(locator_mask)
• Azimuth of Radar Ray(azimuth)
• Signal-to-noise ratio(signal_to_noise_ratio)

• measurements contained in this datastream are unknown

• Signal-to-noise ratio(signal_to_noise_ratio)
• Mean doppler velocity(mean_doppler_velocity)
• lon(lon)
• Locator Mask for Spectra(locator_mask)
• reflectivity(reflectivity)
• Spectra(spectra)
• Spectral velocity bins(velocity_bins)
• North Latitude(lat)
• base time in epoch(base_time)
• Distance to the center of the corresponding range bin(range)
• Doppler spectrum width (second moment of the doppler spectrum)(spectral_width)
• -180.0 - +180.0(alt)
• Beam Elevation Angle(elevation)
• time_in_seconds_since_volume_start(time)
• Time offset from base_time(time_offset)
• Azimuth of Radar Ray(azimuth)

• Nominal radar antenna gain, v channel(radar_antenna_gain_v)
• Radar beam width, vertical channel(radar_beam_width_v)
• Time index of last ray in sweep, 0-based(sweep_end_ray_index)
• platform_type(platform_type)
• half_power_radar_beam_width_h_channel(radar_beam_width_h)
• Time of the calibration that applies to each ray(r_calib_time)
• Primary axis of rotation(primary_axis)
• Nominal radar antenna gain, h channel(radar_antenna_gain_h)
• type_of_instrument(instrument_type)
• antenna_is_in_transition_between_sweeps(antenna_transition)
• calibrated_radar_receiver_gain_v_co_polar_channel(r_calib_receiver_gain_hc)
• Transmit power(r_calib_xmit_power_h)
• Unambiguous range(unambiguous_range)
• Index of first ray in sweep, 0-based(sweep_start_ray_index)
• altitude_above_ground_level(altitude_agl)
• Azimuth of Radar Ray(azimuth)
• Signal-to-noise-ratio(snr)
• Scan rate, positive for clockwise or increasing elevation(scan_rate)
• Noise flor for vertical cross-polar channel 2(r_calib_noise_vx)
• Radar measured transmit power, h channel(radar_measured_transmit_power_h)
• Radar constant, vertical cross-polar channel 2(r_calib_radar_constant_v)
• reflectivity(reflectivity)
• East longitude(longitude)
• Follow mode(follow_mode)
• Receiver gain for vertical cross-polar channel 2(r_calib_receiver_gain_vx)
• time_in_seconds_since_volume_start(time)
• Polarization mode(polarization_mode)
• Radar constant, horizontal copolar channel 1(r_calib_radar_constant_h)
• Unambiguous Doppler velocity(nyquist_velocity)
• radar_calibration_two_way_radome_loss_h_channel(r_calib_two_way_radome_loss_h)
• Pulse width for this calibration(r_calib_pulse_width)
• altitude(altitude)
• Index for the calibration that applies to each ray(r_calib_index)
• lon(lon)
• Distance to the center of the corresponding range bin(range)
• Time corresponding to last radial in file(time_coverage_end)
• transmit_pulse_mode(prt_mode)
• Scan mode for sweep(sweep_mode)
• Mean doppler velocity(mean_doppler_velocity)
• Noise power in noise source region for horizontal copolar channel 1(r_calib_noise_source_power_h)
• Beam Elevation Angle(elevation)
• Number of samples used to compute moments(n_samples)
• radiation_frequency(frequency)
• North Latitude(lat)
• Noise power in noise source region for vertical cross-polar channel(r_calib_noise_source_power_v)
• data_volume_start_time_utc(time_coverage_start)
• data_volume_index_number(volume_number)
• -180.0 - +180.0(alt)
• Sweep number, zero-based count(sweep_number)
• pulse_repetition_frequency(prt)
• base time in epoch(base_time)
• Linear depolarization ratio(linear_depolarization_ratio)
• ray_target_fixed_angle(fixed_angle)
• North latitude(latitude)
• Doppler spectrum width (second moment of the doppler spectrum)(spectral_width)
• Pulse width(pulse_width)
• Noise floor power for horizontal copolar channel1(r_calib_noise_hc)