ESCAPE RaXPol Mobile Radar Data

Jeffrey Snyder (jeffrey.snyder@noaa.gov)
Meteorologist
NOAA/OAR National Severe Storms Laboratory
120 David L. Boren Blvd
Norman, OK 73072
405-325-6567
---
David Bodine (bodine@ou.edu)
Research Scientist
Advanced Radar Research Center
University of Oklahoma
3190 Monitor Ave.
Norman, OK 73071
405-325-2874
---
Boon Leng Cheong (boonleng@ou.edu)
Research Scientist
Advanced Radar Research Center
University of Oklahoma
3190 Monitor Ave., #114
Norman, OK 73071
405-325-3294
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Greg McFarquhar (mcfarq@ou.edu)
Director (CIWRO) and Professor (School of Meteorology)
Cooperative Institute for Severe and High-Impact Weather Research and Operations (CIWRO)
University of Oklahoma
120 David L. Boren Blvd
Norman, OK 73072
405-325-3041
---

Data Contact:  jeffrey.snyder@noaa.gov


1.0 Data Set Overview

Polarimetric weather radar data collected by RaXPol during the ESCAPE field campaign. Minimimally processed (i.e., preliminary) data are available for more rapid perusal/browsing at https://radarhub.arrc.ou.edu/archive/raxpol/. 


2.0 Instrument Description

RaXPol is a rapid-scan, X-band, polarimetric, mobile weather radar. Owing to a high-speed pedestal that can rotate the antenna at up to 180 deg./s and the use of frequency hopping, RaXPol can collect more data more quickly. This allows the radar to scan rapidly (~2 s PPIs) and/or collect higher quality data at more conventional scan speeds (owing to the greater independence between pulse pairs). More technical information about the radar is described in Pazmany et al. (2013), and data from RaXPol has been used in many previous publications. Selected characteristics of the radar are included below.

The radar was principally assigned to provide surviellance coverage during ESCAPE, and it operated in traditional stepped-spiral mode (performing a set of 360 degree PPIs at increasing elevation angles) for the majority of the project. However, after ~June 20th, RaXPol was used to capture high-resolution range-height indicator (RHI) scans for improved vertical resolution and more complete vertical data coverage.  

TABLE 1. Radar parameters during ESCAPE
Center Frequency  9.71 GHz
Bandwidth           40 MHz
Max Rotation Rate 180 deg./s
3 dB Beamwidth    ~1.0 deg.
Range Resolution    75 m
Range Gate Spacing  30 m

3.0 Data Collection & Processing

Several volume coverage patterns (VCPs) were used by RaXPol during ESCAPE. Some  modifications to rotation rate, pulse repitition frequency (PRF), and/or maximum elevation angle were made depending on specific circumstances of the event. Such modifications were generally made to increase data quality (by increasing the number of samples used to calculate the moments, which was done by changing the rotation rate of the antenna and maintaining 1 deg. radial spacing).  In general, RaXPol had a VCP for maximum sensitivity for pre-convection times (VCP 1), a VCP for scanning shallow moist convection or distant deep moist convection (VCP 2), and a VCP for sampling deep moist convection closer to the radar that required a higher maximum elevation angle (VCP 3). 

TABLE 2. General VCPs used by RaXPol during ESCAPE
VCP 1 - 2° to 8° every 1° at 20°/s (Intention: pre-convection, mostly clear air sampling)
VCP 2 - 2° to 15° every 1° at 40°/s (Intention: scattered shallow moist convection)
VCP 3 - 2° to 18° every 2°; 21° to 36° every 3° at 90°/s (Intention: deep moist convection within 30 km of the radar)

Data were converted to CF/Radial using RadxConvert, as part of the LROSE Topaz release.

4.0 Data Format

Data are stored in CfRadial-compliant NetCDF format.  For the majority of cases, each file contains a radar volume, typically a set of PPIs ordered from lowest to highest elevation angle. For RHIs, some cases contain files for which there is a single RHI per file, whereas for others there are multiple RHIs per file. 

EXAMPLE file structure using "ncdump -h"

netcdf cfrad.20220626_181728.000_RaXPol_2.0_v5_SUR {
dimensions:
	time = 2160 ;
	range = 1242 ;
	sweep = 6 ;
	string_length_8 = 8 ;
	string_length_32 = 32 ;
	status_xml_length = 1 ;
variables:
	int volume_number ;
		volume_number:long_name = "data_volume_index_number" ;
		volume_number:units = "" ;
		volume_number:_FillValue = -9999 ;
	char platform_type(string_length_32) ;
		platform_type:long_name = "platform_type" ;
		platform_type:options = "fixed, vehicle, ship, aircraft_fore, aircraft_aft, aircraft_tail, aircraft_belly, aircraft_roof, aircraft_nose, satellite_orbit, satellite_geostat" ;
	char primary_axis(string_length_32) ;
		primary_axis:long_name = "primary_axis_of_rotation" ;
		primary_axis:options = "axis_z, axis_y, axis_x, axis_z_prime, axis_y_prime, axis_x_prime" ;
	char status_xml(status_xml_length) ;
		status_xml:long_name = "status_of_instrument" ;
	char instrument_type(string_length_32) ;
		instrument_type:long_name = "type_of_instrument" ;
		instrument_type:options = "radar, lidar" ;
		instrument_type:meta_group = "instrument_parameters" ;
	float radar_antenna_gain_h ;
		radar_antenna_gain_h:long_name = "nominal_radar_antenna_gain_h_channel" ;
		radar_antenna_gain_h:units = "db" ;
		radar_antenna_gain_h:_FillValue = -9999.f ;
		radar_antenna_gain_h:meta_group = "radar_parameters" ;
	float radar_antenna_gain_v ;
		radar_antenna_gain_v:long_name = "nominal_radar_antenna_gain_v_channel" ;
		radar_antenna_gain_v:units = "db" ;
		radar_antenna_gain_v:_FillValue = -9999.f ;
		radar_antenna_gain_v:meta_group = "radar_parameters" ;
	float radar_beam_width_h ;
		radar_beam_width_h:long_name = "half_power_radar_beam_width_h_channel" ;
		radar_beam_width_h:units = "degrees" ;
		radar_beam_width_h:_FillValue = -9999.f ;
		radar_beam_width_h:meta_group = "radar_parameters" ;
	float radar_beam_width_v ;
		radar_beam_width_v:long_name = "half_power_radar_beam_width_v_channel" ;
		radar_beam_width_v:units = "degrees" ;
		radar_beam_width_v:_FillValue = -9999.f ;
		radar_beam_width_v:meta_group = "radar_parameters" ;
	float radar_rx_bandwidth ;
		radar_rx_bandwidth:long_name = "radar_receiver_bandwidth" ;
		radar_rx_bandwidth:units = "s-1" ;
		radar_rx_bandwidth:_FillValue = -9999.f ;
		radar_rx_bandwidth:meta_group = "radar_parameters" ;
	char time_coverage_start(string_length_32) ;
		time_coverage_start:long_name = "data_volume_start_time_utc" ;
		time_coverage_start:comment = "ray times are relative to start time in secs" ;
	char time_coverage_end(string_length_32) ;
		time_coverage_end:long_name = "data_volume_end_time_utc" ;
	int grid_mapping ;
		grid_mapping:grid_mapping_name = "radar_lidar_radial_scan" ;
	double latitude ;
		latitude:long_name = "latitude" ;
		latitude:units = "degrees_north" ;
		latitude:_FillValue = -9999. ;
	double longitude ;
		longitude:long_name = "longitude" ;
		longitude:units = "degrees_east" ;
		longitude:_FillValue = -9999. ;
	double altitude ;
		altitude:long_name = "altitude" ;
		altitude:units = "meters" ;
		altitude:_FillValue = -9999. ;
		altitude:positive = "up" ;
	double altitude_agl ;
		altitude_agl:long_name = "altitude_above_ground_level" ;
		altitude_agl:units = "meters" ;
		altitude_agl:_FillValue = -9999. ;
		altitude_agl:positive = "up" ;
	int sweep_number(sweep) ;
		sweep_number:long_name = "sweep_index_number_0_based" ;
		sweep_number:units = "" ;
		sweep_number:_FillValue = -9999 ;
	char sweep_mode(sweep, string_length_32) ;
		sweep_mode:long_name = "scan_mode_for_sweep" ;
		sweep_mode:options = "sector, coplane, rhi, vertical_pointing, idle, azimuth_surveillance, elevation_surveillance, sunscan, pointing, calibration, manual_ppi, manual_rhi, sunscan_rhi, doppler_beam_swinging, complex_trajectory, electronic_steering" ;
	char polarization_mode(sweep, string_length_32) ;
		polarization_mode:long_name = "polarization_mode_for_sweep" ;
		polarization_mode:options = "horizontal, vertical, hv_alt, hv_sim, circular" ;
		polarization_mode:meta_group = "radar_parameters" ;
	char prt_mode(sweep, string_length_32) ;
		prt_mode:long_name = "transmit_pulse_mode" ;
		prt_mode:options = "fixed, staggered, dual" ;
		prt_mode:meta_group = "radar_parameters" ;
	char follow_mode(sweep, string_length_32) ;
		follow_mode:long_name = "follow_mode_for_scan_strategy" ;
		follow_mode:options = "none, sun, vehicle, aircraft, target, manual" ;
		follow_mode:meta_group = "instrument_parameters" ;
	float fixed_angle(sweep) ;
		fixed_angle:long_name = "ray_target_fixed_angle" ;
		fixed_angle:units = "degrees" ;
		fixed_angle:_FillValue = -9999.f ;
	float target_scan_rate(sweep) ;
		target_scan_rate:long_name = "target_scan_rate_for_sweep" ;
		target_scan_rate:units = "degrees per second" ;
		target_scan_rate:_FillValue = -9999.f ;
	int sweep_start_ray_index(sweep) ;
		sweep_start_ray_index:long_name = "index_of_first_ray_in_sweep" ;
		sweep_start_ray_index:units = "" ;
		sweep_start_ray_index:_FillValue = -9999 ;
	int sweep_end_ray_index(sweep) ;
		sweep_end_ray_index:long_name = "index_of_last_ray_in_sweep" ;
		sweep_end_ray_index:units = "" ;
		sweep_end_ray_index:_FillValue = -9999 ;
	char rays_are_indexed(sweep, string_length_8) ;
		rays_are_indexed:long_name = "flag_for_indexed_rays" ;
	float ray_angle_res(sweep) ;
		ray_angle_res:long_name = "angular_resolution_between_rays" ;
		ray_angle_res:units = "degrees" ;
		ray_angle_res:_FillValue = -9999.f ;
	double time(time) ;
		time:standard_name = "time" ;
		time:long_name = "time in seconds since volume start" ;
		time:calendar = "gregorian" ;
		time:units = "seconds since 2022-06-26T18:17:28Z" ;
		time:comment = "times are relative to the volume start_time" ;
	float range(range) ;
		range:long_name = "Range from instrument to center of gate" ;
		range:units = "meters" ;
		range:spacing_is_constant = "true" ;
		range:meters_to_center_of_first_gate = 29.9999993294477 ;
		range:meters_between_gates = 29.9999993294477 ;
	float ray_start_range(time) ;
		ray_start_range:long_name = "start_range_for_ray" ;
		ray_start_range:units = "meters" ;
		ray_start_range:_FillValue = -9999.f ;
	float ray_gate_spacing(time) ;
		ray_gate_spacing:long_name = "gate_spacing_for_ray" ;
		ray_gate_spacing:units = "meters" ;
		ray_gate_spacing:_FillValue = -9999.f ;
	float azimuth(time) ;
		azimuth:long_name = "ray_azimuth_angle" ;
		azimuth:units = "degrees" ;
		azimuth:_FillValue = -9999.f ;
	float elevation(time) ;
		elevation:long_name = "ray_elevation_angle" ;
		elevation:units = "degrees" ;
		elevation:_FillValue = -9999.f ;
		elevation:positive = "up" ;
	float pulse_width(time) ;
		pulse_width:long_name = "transmitter_pulse_width" ;
		pulse_width:units = "seconds" ;
		pulse_width:_FillValue = -9999.f ;
		pulse_width:meta_group = "instrument_parameters" ;
	float prt(time) ;
		prt:long_name = "pulse_repetition_time" ;
		prt:units = "seconds" ;
		prt:_FillValue = -9999.f ;
		prt:meta_group = "instrument_parameters" ;
	float prt_ratio(time) ;
		prt_ratio:long_name = "pulse_repetition_frequency_ratio" ;
		prt_ratio:units = "seconds" ;
		prt_ratio:_FillValue = -9999.f ;
		prt_ratio:meta_group = "instrument_parameters" ;
	float nyquist_velocity(time) ;
		nyquist_velocity:long_name = "unambiguous_doppler_velocity" ;
		nyquist_velocity:units = "meters per second" ;
		nyquist_velocity:_FillValue = -9999.f ;
		nyquist_velocity:meta_group = "instrument_parameters" ;
	float unambiguous_range(time) ;
		unambiguous_range:long_name = "unambiguous_range" ;
		unambiguous_range:units = "meters" ;
		unambiguous_range:_FillValue = -9999.f ;
		unambiguous_range:meta_group = "instrument_parameters" ;
	byte antenna_transition(time) ;
		antenna_transition:long_name = "antenna_is_in_transition_between_sweeps" ;
		antenna_transition:units = "" ;
		antenna_transition:_FillValue = -128b ;
		antenna_transition:comment = "1 if antenna is in transition, 0 otherwise" ;
	int n_samples(time) ;
		n_samples:long_name = "number_of_samples_used_to_compute_moments" ;
		n_samples:units = "" ;
		n_samples:_FillValue = -9999 ;
		n_samples:meta_group = "instrument_parameters" ;
	float measured_transmit_power_h(time) ;
		measured_transmit_power_h:long_name = "measured_radar_transmit_power_h_channel" ;
		measured_transmit_power_h:units = "dBm" ;
		measured_transmit_power_h:_FillValue = -9999.f ;
		measured_transmit_power_h:meta_group = "radar_parameters" ;
	float measured_transmit_power_v(time) ;
		measured_transmit_power_v:long_name = "measured_radar_transmit_power_v_channel" ;
		measured_transmit_power_v:units = "dBm" ;
		measured_transmit_power_v:_FillValue = -9999.f ;
		measured_transmit_power_v:meta_group = "radar_parameters" ;
	float scan_rate(time) ;
		scan_rate:long_name = "antenna_angle_scan_rate" ;
		scan_rate:units = "degrees per second" ;
		scan_rate:_FillValue = -9999.f ;
		scan_rate:meta_group = "instrument_parameters" ;
	short DBZ(time, range) ;
		DBZ:long_name = "reflectivity" ;
		DBZ:standard_name = "equivalent_reflectivity_factor" ;
		DBZ:units = "dBZ" ;
		DBZ:sampling_ratio = 1.f ;
		DBZ:_FillValue = -32768s ;
		DBZ:scale_factor = 0.01f ;
		DBZ:add_offset = 0.f ;
		DBZ:grid_mapping = "grid_mapping" ;
		DBZ:coordinates = "time range" ;
	short VEL(time, range) ;
		VEL:long_name = "doppler_velocity" ;
		VEL:standard_name = "radial_velocity_of_scatterers_away_from_instrument" ;
		VEL:units = "m/s" ;
		VEL:sampling_ratio = 1.f ;
		VEL:_FillValue = -32768s ;
		VEL:scale_factor = 0.01f ;
		VEL:add_offset = 0.f ;
		VEL:grid_mapping = "grid_mapping" ;
		VEL:coordinates = "time range" ;
	short WIDTH(time, range) ;
		WIDTH:long_name = "spectrum_width" ;
		WIDTH:standard_name = "doppler_spectrum_width" ;
		WIDTH:units = "m/s" ;
		WIDTH:sampling_ratio = 1.f ;
		WIDTH:_FillValue = -32768s ;
		WIDTH:scale_factor = 0.01f ;
		WIDTH:add_offset = 0.f ;
		WIDTH:grid_mapping = "grid_mapping" ;
		WIDTH:coordinates = "time range" ;
	short ZDR(time, range) ;
		ZDR:long_name = "differential_reflectivity" ;
		ZDR:standard_name = "log_differential_reflectivity_hv" ;
		ZDR:units = "dB" ;
		ZDR:sampling_ratio = 1.f ;
		ZDR:_FillValue = -32768s ;
		ZDR:scale_factor = 0.01f ;
		ZDR:add_offset = 0.f ;
		ZDR:grid_mapping = "grid_mapping" ;
		ZDR:coordinates = "time range" ;
	short RHOHV(time, range) ;
		RHOHV:long_name = "cross_correlation_ratio" ;
		RHOHV:standard_name = "cross_correlation_ratio_hv" ;
		RHOHV:units = "none" ;
		RHOHV:sampling_ratio = 1.f ;
		RHOHV:_FillValue = -32768s ;
		RHOHV:scale_factor = 0.001f ;
		RHOHV:add_offset = 0.f ;
		RHOHV:grid_mapping = "grid_mapping" ;
		RHOHV:coordinates = "time range" ;
	short PHIDP(time, range) ;
		PHIDP:long_name = "differential_phase" ;
		PHIDP:standard_name = "differential_phase_hv" ;
		PHIDP:units = "deg" ;
		PHIDP:sampling_ratio = 1.f ;
		PHIDP:_FillValue = -32768s ;
		PHIDP:scale_factor = 0.01f ;
		PHIDP:add_offset = 0.f ;
		PHIDP:grid_mapping = "grid_mapping" ;
		PHIDP:coordinates = "time range" ;

// global attributes:
		:Conventions = "CF-1.7" ;
		:Sub_conventions = "CF-Radial instrument_parameters radar_parameters platform_velocity" ;
		:version = "CF-Radial-1.3" ;
		:title = "ESCAPE" ;
		:institution = "University of Oklahoma" ;
		:references = "Pazmany et al. (2013)" ;
		:source = "" ;
		:history = "" ;
		:comment = "Preliminary QC includes Z & ZDR calibration and azimuthal rotation correction" ;
		:author = "PIs: Jeffrey Snyder (NSSL; jeffrey.snyder@noaa.gov), David Bodine (OU; bodine@ou.edu), Greg McFarquhar (OU; mcfarq@ou.edu)" ;
		:original_format = "CFRADIAL" ;
		:driver = "RadxConvert(NCAR)" ;
		:created = "2023/01/12 06:34:52.855" ;
		:start_datetime = "2022-06-26T18:17:28Z" ;
		:time_coverage_start = "2022-06-26T18:17:28Z" ;
		:start_time = "2022-06-26 18:17:28.000" ;
		:end_datetime = "2022-06-26T18:18:13Z" ;
		:time_coverage_end = "2022-06-26T18:18:13Z" ;
		:end_time = "2022-06-26 18:18:13.000" ;
		:instrument_name = "RaXPol_2.0" ;
		:site_name = "SE5" ;
		:scan_name = "" ;
		:scan_id = 0 ;
		:platform_is_mobile = "true" ;
		:n_gates_vary = "false" ;
		:ray_times_increase = "true" ;
}


EXAMPLE RHI VOLUME using "ncdump -h"

netcdf cfrad.20220626_181929.000_RaXPol_2.0_v7_RHI {
dimensions:
	time = 890 ;
	range = 1242 ;
	sweep = 27 ;
	string_length_8 = 8 ;
	string_length_32 = 32 ;
	status_xml_length = 1 ;
variables:
	int volume_number ;
		volume_number:long_name = "data_volume_index_number" ;
		volume_number:units = "" ;
		volume_number:_FillValue = -9999 ;
	char platform_type(string_length_32) ;
		platform_type:long_name = "platform_type" ;
		platform_type:options = "fixed, vehicle, ship, aircraft_fore, aircraft_aft, aircraft_tail, aircraft_belly, aircraft_roof, aircraft_nose, satellite_orbit, satellite_geostat" ;
	char primary_axis(string_length_32) ;
		primary_axis:long_name = "primary_axis_of_rotation" ;
		primary_axis:options = "axis_z, axis_y, axis_x, axis_z_prime, axis_y_prime, axis_x_prime" ;
	char status_xml(status_xml_length) ;
		status_xml:long_name = "status_of_instrument" ;
	char instrument_type(string_length_32) ;
		instrument_type:long_name = "type_of_instrument" ;
		instrument_type:options = "radar, lidar" ;
		instrument_type:meta_group = "instrument_parameters" ;
	float radar_antenna_gain_h ;
		radar_antenna_gain_h:long_name = "nominal_radar_antenna_gain_h_channel" ;
		radar_antenna_gain_h:units = "db" ;
		radar_antenna_gain_h:_FillValue = -9999.f ;
		radar_antenna_gain_h:meta_group = "radar_parameters" ;
	float radar_antenna_gain_v ;
		radar_antenna_gain_v:long_name = "nominal_radar_antenna_gain_v_channel" ;
		radar_antenna_gain_v:units = "db" ;
		radar_antenna_gain_v:_FillValue = -9999.f ;
		radar_antenna_gain_v:meta_group = "radar_parameters" ;
	float radar_beam_width_h ;
		radar_beam_width_h:long_name = "half_power_radar_beam_width_h_channel" ;
		radar_beam_width_h:units = "degrees" ;
		radar_beam_width_h:_FillValue = -9999.f ;
		radar_beam_width_h:meta_group = "radar_parameters" ;
	float radar_beam_width_v ;
		radar_beam_width_v:long_name = "half_power_radar_beam_width_v_channel" ;
		radar_beam_width_v:units = "degrees" ;
		radar_beam_width_v:_FillValue = -9999.f ;
		radar_beam_width_v:meta_group = "radar_parameters" ;
	float radar_rx_bandwidth ;
		radar_rx_bandwidth:long_name = "radar_receiver_bandwidth" ;
		radar_rx_bandwidth:units = "s-1" ;
		radar_rx_bandwidth:_FillValue = -9999.f ;
		radar_rx_bandwidth:meta_group = "radar_parameters" ;
	char time_coverage_start(string_length_32) ;
		time_coverage_start:long_name = "data_volume_start_time_utc" ;
		time_coverage_start:comment = "ray times are relative to start time in secs" ;
	char time_coverage_end(string_length_32) ;
		time_coverage_end:long_name = "data_volume_end_time_utc" ;
	int grid_mapping ;
		grid_mapping:grid_mapping_name = "radar_lidar_radial_scan" ;
	double latitude ;
		latitude:long_name = "latitude" ;
		latitude:units = "degrees_north" ;
		latitude:_FillValue = -9999. ;
	double longitude ;
		longitude:long_name = "longitude" ;
		longitude:units = "degrees_east" ;
		longitude:_FillValue = -9999. ;
	double altitude ;
		altitude:long_name = "altitude" ;
		altitude:units = "meters" ;
		altitude:_FillValue = -9999. ;
		altitude:positive = "up" ;
	double altitude_agl ;
		altitude_agl:long_name = "altitude_above_ground_level" ;
		altitude_agl:units = "meters" ;
		altitude_agl:_FillValue = -9999. ;
		altitude_agl:positive = "up" ;
	int sweep_number(sweep) ;
		sweep_number:long_name = "sweep_index_number_0_based" ;
		sweep_number:units = "" ;
		sweep_number:_FillValue = -9999 ;
	char sweep_mode(sweep, string_length_32) ;
		sweep_mode:long_name = "scan_mode_for_sweep" ;
		sweep_mode:options = "sector, coplane, rhi, vertical_pointing, idle, azimuth_surveillance, elevation_surveillance, sunscan, pointing, calibration, manual_ppi, manual_rhi, sunscan_rhi, doppler_beam_swinging, complex_trajectory, electronic_steering" ;
	char polarization_mode(sweep, string_length_32) ;
		polarization_mode:long_name = "polarization_mode_for_sweep" ;
		polarization_mode:options = "horizontal, vertical, hv_alt, hv_sim, circular" ;
		polarization_mode:meta_group = "radar_parameters" ;
	char prt_mode(sweep, string_length_32) ;
		prt_mode:long_name = "transmit_pulse_mode" ;
		prt_mode:options = "fixed, staggered, dual" ;
		prt_mode:meta_group = "radar_parameters" ;
	char follow_mode(sweep, string_length_32) ;
		follow_mode:long_name = "follow_mode_for_scan_strategy" ;
		follow_mode:options = "none, sun, vehicle, aircraft, target, manual" ;
		follow_mode:meta_group = "instrument_parameters" ;
	float fixed_angle(sweep) ;
		fixed_angle:long_name = "ray_target_fixed_angle" ;
		fixed_angle:units = "degrees" ;
		fixed_angle:_FillValue = -9999.f ;
	float target_scan_rate(sweep) ;
		target_scan_rate:long_name = "target_scan_rate_for_sweep" ;
		target_scan_rate:units = "degrees per second" ;
		target_scan_rate:_FillValue = -9999.f ;
	int sweep_start_ray_index(sweep) ;
		sweep_start_ray_index:long_name = "index_of_first_ray_in_sweep" ;
		sweep_start_ray_index:units = "" ;
		sweep_start_ray_index:_FillValue = -9999 ;
	int sweep_end_ray_index(sweep) ;
		sweep_end_ray_index:long_name = "index_of_last_ray_in_sweep" ;
		sweep_end_ray_index:units = "" ;
		sweep_end_ray_index:_FillValue = -9999 ;
	char rays_are_indexed(sweep, string_length_8) ;
		rays_are_indexed:long_name = "flag_for_indexed_rays" ;
	float ray_angle_res(sweep) ;
		ray_angle_res:long_name = "angular_resolution_between_rays" ;
		ray_angle_res:units = "degrees" ;
		ray_angle_res:_FillValue = -9999.f ;
	double time(time) ;
		time:standard_name = "time" ;
		time:long_name = "time in seconds since volume start" ;
		time:calendar = "gregorian" ;
		time:units = "seconds since 2022-06-26T18:19:29Z" ;
		time:comment = "times are relative to the volume start_time" ;
	float range(range) ;
		range:long_name = "Range from instrument to center of gate" ;
		range:units = "meters" ;
		range:spacing_is_constant = "true" ;
		range:meters_to_center_of_first_gate = 29.9999993294477 ;
		range:meters_between_gates = 29.9999993294477 ;
	float ray_start_range(time) ;
		ray_start_range:long_name = "start_range_for_ray" ;
		ray_start_range:units = "meters" ;
		ray_start_range:_FillValue = -9999.f ;
	float ray_gate_spacing(time) ;
		ray_gate_spacing:long_name = "gate_spacing_for_ray" ;
		ray_gate_spacing:units = "meters" ;
		ray_gate_spacing:_FillValue = -9999.f ;
	float azimuth(time) ;
		azimuth:long_name = "ray_azimuth_angle" ;
		azimuth:units = "degrees" ;
		azimuth:_FillValue = -9999.f ;
	float elevation(time) ;
		elevation:long_name = "ray_elevation_angle" ;
		elevation:units = "degrees" ;
		elevation:_FillValue = -9999.f ;
		elevation:positive = "up" ;
	float pulse_width(time) ;
		pulse_width:long_name = "transmitter_pulse_width" ;
		pulse_width:units = "seconds" ;
		pulse_width:_FillValue = -9999.f ;
		pulse_width:meta_group = "instrument_parameters" ;
	float prt(time) ;
		prt:long_name = "pulse_repetition_time" ;
		prt:units = "seconds" ;
		prt:_FillValue = -9999.f ;
		prt:meta_group = "instrument_parameters" ;
	float prt_ratio(time) ;
		prt_ratio:long_name = "pulse_repetition_frequency_ratio" ;
		prt_ratio:units = "seconds" ;
		prt_ratio:_FillValue = -9999.f ;
		prt_ratio:meta_group = "instrument_parameters" ;
	float nyquist_velocity(time) ;
		nyquist_velocity:long_name = "unambiguous_doppler_velocity" ;
		nyquist_velocity:units = "meters per second" ;
		nyquist_velocity:_FillValue = -9999.f ;
		nyquist_velocity:meta_group = "instrument_parameters" ;
	float unambiguous_range(time) ;
		unambiguous_range:long_name = "unambiguous_range" ;
		unambiguous_range:units = "meters" ;
		unambiguous_range:_FillValue = -9999.f ;
		unambiguous_range:meta_group = "instrument_parameters" ;
	byte antenna_transition(time) ;
		antenna_transition:long_name = "antenna_is_in_transition_between_sweeps" ;
		antenna_transition:units = "" ;
		antenna_transition:_FillValue = -128b ;
		antenna_transition:comment = "1 if antenna is in transition, 0 otherwise" ;
	int n_samples(time) ;
		n_samples:long_name = "number_of_samples_used_to_compute_moments" ;
		n_samples:units = "" ;
		n_samples:_FillValue = -9999 ;
		n_samples:meta_group = "instrument_parameters" ;
	float measured_transmit_power_h(time) ;
		measured_transmit_power_h:long_name = "measured_radar_transmit_power_h_channel" ;
		measured_transmit_power_h:units = "dBm" ;
		measured_transmit_power_h:_FillValue = -9999.f ;
		measured_transmit_power_h:meta_group = "radar_parameters" ;
	float measured_transmit_power_v(time) ;
		measured_transmit_power_v:long_name = "measured_radar_transmit_power_v_channel" ;
		measured_transmit_power_v:units = "dBm" ;
		measured_transmit_power_v:_FillValue = -9999.f ;
		measured_transmit_power_v:meta_group = "radar_parameters" ;
	float scan_rate(time) ;
		scan_rate:long_name = "antenna_angle_scan_rate" ;
		scan_rate:units = "degrees per second" ;
		scan_rate:_FillValue = -9999.f ;
		scan_rate:meta_group = "instrument_parameters" ;
	short DBZ(time, range) ;
		DBZ:long_name = "reflectivity" ;
		DBZ:standard_name = "equivalent_reflectivity_factor" ;
		DBZ:units = "dBZ" ;
		DBZ:sampling_ratio = 1.f ;
		DBZ:_FillValue = -32768s ;
		DBZ:scale_factor = 0.01f ;
		DBZ:add_offset = 0.f ;
		DBZ:grid_mapping = "grid_mapping" ;
		DBZ:coordinates = "time range" ;
	short VEL(time, range) ;
		VEL:long_name = "doppler_velocity" ;
		VEL:standard_name = "radial_velocity_of_scatterers_away_from_instrument" ;
		VEL:units = "m/s" ;
		VEL:sampling_ratio = 1.f ;
		VEL:_FillValue = -32768s ;
		VEL:scale_factor = 0.01f ;
		VEL:add_offset = 0.f ;
		VEL:grid_mapping = "grid_mapping" ;
		VEL:coordinates = "time range" ;
	short WIDTH(time, range) ;
		WIDTH:long_name = "spectrum_width" ;
		WIDTH:standard_name = "doppler_spectrum_width" ;
		WIDTH:units = "m/s" ;
		WIDTH:sampling_ratio = 1.f ;
		WIDTH:_FillValue = -32768s ;
		WIDTH:scale_factor = 0.01f ;
		WIDTH:add_offset = 0.f ;
		WIDTH:grid_mapping = "grid_mapping" ;
		WIDTH:coordinates = "time range" ;
	short ZDR(time, range) ;
		ZDR:long_name = "differential_reflectivity" ;
		ZDR:standard_name = "log_differential_reflectivity_hv" ;
		ZDR:units = "dB" ;
		ZDR:sampling_ratio = 1.f ;
		ZDR:_FillValue = -32768s ;
		ZDR:scale_factor = 0.01f ;
		ZDR:add_offset = 0.f ;
		ZDR:grid_mapping = "grid_mapping" ;
		ZDR:coordinates = "time range" ;
	short RHOHV(time, range) ;
		RHOHV:long_name = "cross_correlation_ratio" ;
		RHOHV:standard_name = "cross_correlation_ratio_hv" ;
		RHOHV:units = "none" ;
		RHOHV:sampling_ratio = 1.f ;
		RHOHV:_FillValue = -32768s ;
		RHOHV:scale_factor = 0.001f ;
		RHOHV:add_offset = 0.f ;
		RHOHV:grid_mapping = "grid_mapping" ;
		RHOHV:coordinates = "time range" ;
	short PHIDP(time, range) ;
		PHIDP:long_name = "differential_phase" ;
		PHIDP:standard_name = "differential_phase_hv" ;
		PHIDP:units = "deg" ;
		PHIDP:sampling_ratio = 1.f ;
		PHIDP:_FillValue = -32768s ;
		PHIDP:scale_factor = 0.01f ;
		PHIDP:add_offset = 0.f ;
		PHIDP:grid_mapping = "grid_mapping" ;
		PHIDP:coordinates = "time range" ;

// global attributes:
		:Conventions = "CF-1.7" ;
		:Sub_conventions = "CF-Radial instrument_parameters radar_parameters platform_velocity" ;
		:version = "CF-Radial-1.3" ;
		:title = "ESCAPE" ;
		:institution = "University of Oklahoma" ;
		:references = "Pazmany et al. (2013)" ;
		:source = "" ;
		:history = "" ;
		:comment = "Preliminary QC includes Z & ZDR calibration and azimuthal rotation correction" ;
		:author = "PIs: Jeffrey Snyder (NSSL; jeffrey.snyder@noaa.gov), David Bodine (OU; bodine@ou.edu), Greg McFarquhar (OU; mcfarq@ou.edu)" ;
		:original_format = "CFRADIAL" ;
		:driver = "RadxConvert(NCAR)" ;
		:created = "2023/01/12 06:34:59.125" ;
		:start_datetime = "2022-06-26T18:19:29Z" ;
		:time_coverage_start = "2022-06-26T18:19:29Z" ;
		:start_time = "2022-06-26 18:19:29.000" ;
		:end_datetime = "2022-06-26T18:23:24Z" ;
		:time_coverage_end = "2022-06-26T18:23:24Z" ;
		:end_time = "2022-06-26 18:23:24.000" ;
		:instrument_name = "RaXPol_2.0" ;
		:site_name = "SE5" ;
		:scan_name = "" ;
		:scan_id = 0 ;
		:platform_is_mobile = "true" ;
		:n_gates_vary = "false" ;
		:ray_times_increase = "true" ;
}


5.0 Data Remarks


6.0 References

Pazmany, A. L., J. B. Mead, H. B. Bluestein, J. C. Snyder, and J. B. Houser, 2013: A 
mobile Rapid-Scanning X-band Polarimetric (RaXPol) Doppler radar system. J. Atmos. 
Oceanic Technol., 30, 1398–1413, https://doi.org/10.1175/JTECH-D-12-00166.1.