File format for v3 radial data

An overview of the radar measurement technique and of the meanings of the data products are given here. More details about the spectral level processing can be found here. These files contain radial (i.e. along-beam) profiles of the radar return parameters (signal power, Doppler shift and spectral width) for different beam pointing directions. Multiple signal components are typically identified for each spectrum. Data are recorded at 150 m intervals in range and cover the approximate range 2 - 20 (for the ST mode) or 58 - 96 km (for the M mode). For most purposes the Cartesian data will suffice and it should only be necessary to examine the radial data for specialist studies.
Click here to find out about the contents of other files.

Availability Data processed by version-3 software are currently available from 20th June 2006 until the present. The entire archive will eventually be reprocessed. Please contact the NERC MST Radar Facility Project Scientist if you would like v3 data for earlier dates.

File naming convention:
radar-mst_capel-dewi_YYYYMMDD_AARRR_radial_v3.nc

	YYYY		is a 4-digit year [1990 - ]
	MM		is a 2-digit month [01 - 12]
	DD		is a 2-digit day [01 - 31]
	AA		is the altitude mode ['st': approximately 2 - 20 km | 'm': approximately 58 - 96 km]
	RRR		is the range resolution (m) [150 | 300 | 600 | 1200 | 2400 | 4800]
	.nc		represents that this is a netCDF file

i.e. radar-mst_capel-dewi_20050101_st300_radial_v3.nc contains 300 m resolution Cartesian data over the ST altitude range for 1st January 2005.
Click here for the background to the file naming convention.

File location:
ST-mode: /badc/mst/data/mst-products-v3/st-mode/radial/
M-mode: /badc/mst/data/mst-products-v3/m-mode/radial/
Click here for the location of other files.

Archiving convention: YYYY/MM
Click here for a further explanation.

netCDF File Structure using the st300 file for 20th June 2006 as an example - click here for an explanation

List of Global attributes - Click on the name to view the value

char Conventions

char title

char institution

char source

char history

char references

char comment

short data_year

short data_month

short data_day

char data_altitude_mode

float data_range_resolution_m

short data_range_resolution_number

short data_bottom_range_gate_number

short data_top_range_gate_number

float radar_frequency_MHz

float radar_wavelength_m

char radar_transmitters

float radar_peak_transmitted_power_kW

char radar_antenna_type

float radar_antenna_side_length_m

float radar_beam_one_way_half_power_half_width_degrees

char radar_location_name

float radar_latitude_degrees_north

float radar_longitude_degrees_east

float radar_altitude_above_mean_sea_level_m

char radar_british_national_grid_reference

short signal_processing_version_number

short signal_processing_sub_version_number

short sig_lims_nr_vel_bins_smoothing

float sig_lims_min_norm_psd

float sig_lims_max_norm_psd_at_local_min

float sig_lims_min_peak_smooth_psd_to_noise_dB_to_flag

short radial_cont_checks_have_been_applied

float radial_cont_min_sig_width_ratio

float radial_cont_max_sig_width_ratio

float radial_cont_min_sig_overlap_ratio

float radial_cont_link_std_dev_radial_vel_mps

float radial_cont_link_std_dev_range_m

float radial_cont_min_unambiguous_link_weight

float radial_cont_min_ratio_of_max_link_weight_for_search

float radial_cont_max_std_dev_sig_power_dB_for_intf

float radial_cont_min_fraction_of_range_gates_for_alternative_path

short radial_cont_apply_lower_path_correction

float radial_cont_max_altitude_amsl_m_for_lower_path_correction

float radial_cont_max_link_radial_vel_sep_mps

float radial_cont_chain_fill_max_radial_vel_sep_mps

float time_cont_uni_dirn_time_radius_mins

float time_cont_bi_dirn_time_radius_mins

float time_cont_max_vert_vel_comp_diff_mps

float time_cont_max_horiz_vel_comp_diff_mps

float time_cont_min_nr_buddies_fixed_coeff

float time_cont_min_nr_buddies_scale_coeff

short time_cont_min_nr_dwells_to_apply

List of Dimensions - Click on the name to view the corresponding coordinate variable

time

range

signal_component_number

List of Variables - Click on a name to view the corresponding attributes

float time (time)

float range (range)

float latitude ()

float longitude ()

byte signal_component_number (signal_component_number)

byte signal_component_is_reliable (time, range, signal_component_number)

short signal_component_reliability_details (time, range, signal_component_number)

float signal_power (time, range, signal_component_number)

float radial_velocity (time, range, signal_component_number)

float spectral_width (time, range, signal_component_number)

short first_velocity_bin_number (time, range, signal_component_number)

short final_velocity_bin_number (time, range, signal_component_number)

byte peak_smooth_psd_to_noise (time, range, signal_component_number)

float noise_power (time, range)

byte beam_pointing_direction_number (time)

float beam_pointing_azimuth_angle (time)

float beam_pointing_zenith_angle (time)

byte length_of_transmitter_pulse (time)

byte sub_length_of_transmitter_pulse (time)

short inter_pulse_period (time)

short number_of_coherent_integrations (time)

short number_of_complex_samples_in_discrete_fourier_transform (time)

byte data_weighting_window_index (time)

byte number_of_incoherent_integrations (time)

float spectral_velocity_bin_spacing (time)

byte alternative_profile_details (time)

short time_index_of_first_dwell_in_cycle (time)

byte dwell_number (time)

List of Global Attribute values
char Conventions = "CF-1.0"

char title = "46.5 MHz wind-profiling radar radial data - st300 mode"

char institution = "
  Data recorded by the Natural Environment Research Council (NERC)
Mesosphere-Stratosphere-Troposphere (MST) Radar Facility at Aberystwyth
- http://mst.nerc.ac.uk
  Data processed by the Rutherford Appleton Laboratory, Space Science and
Technology Department - http://www.sstd.rl.ac.uk
  Data held at the British Atmospheric Data Centre
http://badc.nerc.ac.uk/data/mst"

char source = "
  The Natural Environment Research Council (NERC) Mesosphere-Stratosphere-
Troposphere (MST) Radar at Aberystwyth"

char history = "File created 2007-05-28 04:49:06 +00:00 on machine claudius"

char references = "
  Basic information about the data is available at
http://badc.nerc.ac.uk/data/mst
  More detailed information about the data is available at
http://mst.nerc.ac.uk"

char comment = "
  The Natural Environment Research Council (NERC) Mesosphere-Stratosphere-
Troposphere (MST) Radar at Aberystwyth (UK) is a 46.5 MHz
wind-profiling instrument. It transmits short pulses of radio waves
which are scattered back to it from atmospheric targets. The distance
of a target from the instrument is determined by the time delay
between the transmission and reception of a pulse. The main targets
are metre-scale refractive index irregularities, which are referred to
as clear-air targets (the term does not necessarily imply clear-sky
conditions as the radar is able to see through clouds). Hydrometeors,
aircraft, and ground-based objects can also give rise to radar
returns. The receiver signal is occasionally contaminated by
interference. The refractive index irregularities are caused by
variations in atmospheric humidity (within the lowest 10 km of the
atmosphere), in atmospheric density (within the lowest few 10s of km)
and in free electron density (above 50 km). The radar return signal
power is typically proportional to the square of the mean vertical
gradient of the (potential) refractive index and inversely
proportional to the square of the range of the clear-air targets from
the radar. The refractive index irregularities are assumed to be
advected with the wind. Consequently the radial velocity, i.e. the
component of the wind vector along the radar beam pointing direction,
can be inferred from the Doppler shift of the radar return
signal. Atmospheric turbulence gives rise to variability in the radial
velocity when observed over a time scale of a few tens of
seconds. However, as a result of the radar\'s finite beam width, the
observed spread tends to be dominated by a beam-broadening component,
which is proportional to the horizontal wind speed. Consequently it
becomes increasingly difficult to infer turbulence intensities as the
wind speed increases.
  The radar receiver signal is sampled at 1.0 us intervals following
the transmission of a pulse. This corresponds to sampling at 150.0 m
intervals in range from the radar. It is necessary to sample both the
in-phase (I) and quadrature (Q) components of the receiver signal
(i.e. complex values) in order to allow both the magnitude and the
sign of the Doppler shift to be inferred. In the m-mode samples are
recorded between ranges of approximately 60 and 90 km. In the st-mode
samples are recorded between ranges of approximately 2 and 20 km. It
is possible to operate the radar in mst-mode so that both altitude
ranges are sampled simultaneously. The range resolution of the radar
returns is determined by the length of the transmitter pulse (not by
the sampling interval), to which the receiver bandwidth must be
matched. The range resolution can be increased by using complementary
coding. This requires the phase of sub-lengths of the transmitter
pulse to be offset by either 0 or 180 degrees according to a set
coding pattern. The range resolution is then determined by the
sub-length of the transmitter pulse (to which the receiver bandwidth
is matched).
  No attempt is made to derive radar return signal parameters until
samples have been acquired for a large, pre-determined number of
pulses - typically covering a few tens of seconds. The term dwell is
used to refer to this collection interval or to range profiles of any
of the data products associated with it. A dwell initially consists of
a complex time series, for each range gate, of I and Q samples which
are separated in time by the inter pulse period (of the order of a
millisecond). The nature of the samples changes only slowly from pulse
to pulse and so coherent integration is applied - for each range gate,
groups of consecutive samples are summed together. The number of
complex samples in the resulting time series is thus reduced, and the
time interval between them is increased, by a factor equal to the
number of coherent integrations (typically of the order of a few
hundred). The time interval between the new samples (typically of the
order of 0.1 s) determines the Nyquist velocity (typically of the
order of 10 m/s), the maximum radial velocity that can be
unambiguously determined. Decoding must be applied to the coherently
integrated samples if a complementary transmitter code has been
used. For each range gate, a complex Doppler frequency spectrum is
derived by applying a weighting window to the complex time series data
followed by a discrete Fourier transform. This spectrum is multiplied
by its complex conjugate to give a power spectrum. Doppler frequencies
are converted into Doppler velocities by multiplying by half the radar
wavelength. The sign must be changed so that movement away from the
radar (which gives rise to a negative frequency shift) is represented
by a positive velocity. If desired, consecutively-observed Doppler
velocity power spectra may be incoherently integrated by adding them
together. This increases the detectability of signals. In general a
Doppler velocity power spectrum contains one or more signal components
superimposed on a background of nominally white noise. The power
spectral densities (PSDs) of the velocity bins around zero velocity
(the number depends on the data weighting window used) are typically
contaminated by dc biases in the time-series samples. The values must
be replaced by linearly interpolating between the PSDs of adjacent
velocity bins. The noise power is dominated by broad-band lower-VHF
cosmic radiation, which undergoes a diurnal variation by a factor of
approximately 2.
  For each Doppler velocity power spectrum, the noise power spectral
density (PSD) is determined by the statistical method of Hildebrand
and Sekhon (1974). The noise power is equal to the noise PSD summed
across the width of the spectrum. The velocity bin limits of the
strongest signal component are determined by first locating the peak
value of the running-mean-smoothed PSD. The smoothed PSD is then
followed to either side until one of the following conditions is
encountered: the smoothed PSD has dropped below the noise PSD, the
smoothed PSD has dropped below a set fraction of the peak value, or a
local minimum is encountered (and the smoothed PSD is below a set
fraction of the peak value). The final criterion is particularly
important under stratiform precipitation conditions in order to
separate partially-overlapping clear-air and hydrometeor signal
components. The PSDs within the signal limits first have the noise PSD
subtracted and are then compensated for the low-pass-filtering effect
of coherent integration. The zeroth (m0), first (m1) and second (m2)
order moments (of the corrected PSDs within the signal limits) are
calculated in order to derive the signal power (m0), the radial
velocity (m1/m0) and the spectral width (sqrt[(m2/m0) -
(m1/m0)**2]). For st-mode observations it is desirable to identify
more than one signal component per spectrum (typically two). A radial
continuity algorithm is then used to identify the primary signal
component for each range gate, i.e. that which leads to the most
likely overall clear-air radar return profile. A second attempt may be
made to identify the primary signal components if the first profile is
deemed to be contaminated by interference. A final attempt is made to
improve the selection of primary signal components for the lowest
range gates in case of contamination by hydrometeor
returns. Subsequently attention is confined to the primary signal
components. Nevertheless, the radar return parameters for the
non-primary signal components are saved in the radial data files as
they may contain scientifically useful information, e.g. concerning
precipitation.
  For wind-profiling purposes, MST radar observations are cycled
through a sequence of dwells with different beam pointing
directions. The radial velocity for each dwell is assumed to represent
the the dot product of the three-dimensional wind vector and a unit
vector along the beam pointing direction. The radial velocity observed
by a vertical beam (i.e. a dwell with a beam pointing zenith angle of
zero) is therefore assumed to be equal to the vertical component of
the wind. The radial velocity observed by an off-vertical beam (i.e. a
dwell with a small, non-zero beam pointing zenith angle) is assumed to
represent the vector sum of the vertical component of the wind
multiplied by the cosine of the zenith angle, and the component of the
horizontal wind along the the radar beam pointing azimuth multiplied
by the sine of the zenith angle. Consequently a component of the
horizontal wind can be derived for each vertical/off-vertical beam
pair. When more than one vertical beam observation is made per cycle,
that closest in time to the off-vertical beam observation is used for
deriving the horizontal wind components. When combining vertical and
off-vertical beam radial velocity components, vertical beam data are
taken from those range gates which are most closely matched in
altitude to the off-vertical beam range gates. A time continuity
algorithm is applied to the horizontal wind components for the
off-vertical beams, and to the vertical wind components for the
vertical beams, as a further test for reliability. Time continuity is
first established uni-directionally, i.e. by comparing the
observations to be flagged only with those made at earlier times. This
allows wind-profile data to be made available with only a short time
delay. However, the process is repeated as soon as there are
sufficient subsequent observations to allow bi-directional flagging to
be applied. The overall reliability of signal components requires them
to have passed both radial continuity (when the tests have been made)
and time continuity tests."

short data_year = 2006

short data_month = 6

short data_day = 20

char data_altitude_mode = "st"

float data_range_resolution_m = 300.0

short data_range_resolution_number = 2

short data_bottom_range_gate_number = 18

short data_top_range_gate_number = 147

float radar_frequency_MHz = 46.5

float radar_wavelength_m = 6.45

char radar_transmitters = "5 Tycho Technology WPT-50s"

float radar_peak_transmitted_power_kW = 160.0

char radar_antenna_type = "20 by 20 array of 4-element Yagi aerials with 0.85 wavelength spacing"

float radar_antenna_side_length_m = 104.12

float radar_beam_one_way_half_power_half_width_degrees = 1.5

char radar_location_name = "Capel Dewi (near Aberystwyth, UK)"

float radar_latitude_degrees_north = 52.42

float radar_longitude_degrees_east = -4.01

float radar_altitude_above_mean_sea_level_m = 50.0

char radar_british_national_grid_reference = "SN637826"

short signal_processing_version_number = 3

short signal_processing_sub_version_number = 2

short sig_lims_nr_vel_bins_smoothing = 5

float sig_lims_min_norm_psd = 0.01

float sig_lims_max_norm_psd_at_local_min = 0.1

float sig_lims_min_peak_smooth_psd_to_noise_dB_to_flag = 10.0

short radial_cont_checks_have_been_applied = 1

float radial_cont_min_sig_width_ratio = 0.67

float radial_cont_max_sig_width_ratio = 1.33

float radial_cont_min_sig_overlap_ratio = 0.67

float radial_cont_link_std_dev_radial_vel_mps = 1.0

float radial_cont_link_std_dev_range_m = 1000.0

float radial_cont_min_unambiguous_link_weight = 0.9

float radial_cont_min_ratio_of_max_link_weight_for_search = 0.25

float radial_cont_max_std_dev_sig_power_dB_for_intf = 3.0

float radial_cont_min_fraction_of_range_gates_for_alternative_path = 0.25

short radial_cont_apply_lower_path_correction = 1

float radial_cont_max_altitude_amsl_m_for_lower_path_correction = 5000.0

float radial_cont_max_link_radial_vel_sep_mps = 2.0

float radial_cont_chain_fill_max_radial_vel_sep_mps = 1.0

float time_cont_uni_dirn_time_radius_mins = 60.0

float time_cont_bi_dirn_time_radius_mins = 30.0

float time_cont_max_vert_vel_comp_diff_mps = 1.0

float time_cont_max_horiz_vel_comp_diff_mps = 10.0

float time_cont_min_nr_buddies_fixed_coeff = 1.0

float time_cont_min_nr_buddies_scale_coeff = 0.5

short time_cont_min_nr_dwells_to_apply = 2


List of Variable attribute values

float time (time)

standard_name = "time"

long_name = "UTC"

units = "seconds since 2006-06-20 00:00:00 +00:00"

axis = "T"

comment = "Times refer to the start of a dwell."

float range (range)

long_name = "Range from the radar"

units = "m"

axis = "Z"

comment = "
  The range is the distance from the radar's antenna array to the
centre of each range gate. The radar is located 50 m above mean sea
level and so the altitude of a range gate in metres above mean sea
level is given by
  50.0 +
  (range[range_index] *
  cos(beam_pointing_zenith_angle[time_index] * pi/180.0))"

float latitude ()

standard_name = "latitude"

long_name = "Radar latitude"

units = "degrees_north"

axis = "Y"

float longitude ()

standard_name = "longitude"

long_name = "Radar longitude"

units = "degrees_east"

axis = "X"

byte signal_component_number (signal_component_number)

long_name = "Signal component number"

units = "1"

comment = "
  When more than one signal component is identified within each
spectrum, the primary signal component (i.e. that with signal
component number 0) is the one which leads to the most likely overall
clear-air profile. Non-primary signal components are ordered
arbitrarily."

byte signal_component_is_reliable (time, range, signal_component_number)

long_name = "Signal component reliability flag"

units = "1"

flag_values = 0 1 b

flag_meanings = "signal_component_is_not_reliable signal_component_is_reliable"

coordinates = "latitude longitude"

comment = "
  The reliability flag and reliability details apply to variables
signal_power, radial_velocity, spectral_width, first_velocity_bin_number,
final_velocity_bin_number, and peak_smooth_psd_to_noise.
  It is important to use the reliability flag to select useful data
points as, in most cases, unreliable values are not replaced with
missing datum values."

byte signal_component_reliability_details (time, range, signal_component_number)

long_name = "Signal component reliability details"

units = "1"

coordinates = "latitude longitude"

comment = "
  The reliability flag and reliability details apply to variables
signal_power, radial_velocity, spectral_width, first_velocity_bin_number,
final_velocity_bin_number, and peak_smooth_psd_to_noise.
  The details by means of which the reliability of a data product is
determined are coded bitwise into a 14-bit unsigned integer (albeit
stored as a 16-bit signed integer) for which bit 00 is the least
significant bit. Not all bits are used by every data product.
  bit 00: 1 if the signal component is available
  bit 01: 1 if the peak smoothed power spectral density (PSD) is greater
   than sig_lims_min_peak_smooth_psd_to_noise_dB_to_flag (a
   global attribute) above the noise PSD
  bit 02: 1 if the signal component belongs to a radial chain
  bit 03: 1 if the signal component fits overall radial continuity
  bit 04: 1 if a secondary signal component belongs to a radial chain
  bit 05: 1 if the signal component has passed a uni-directional time
   continuity test
  bit 06: 1 if the signal component has passed a bi-directional time
   continuity test
  bit 07: 1 if a complementary beam exists
  bit 08: 1 if the complementary horizontal wind components have both passed
   lower order reliability tests
  bit 09: 1 if the complementary horizontal wind components have both passed
   lower order reliability tests for the orthogonal azimuth
  bit 10: 1 if the complementary horizontal wind components differ by
   less than cart_max_compl_beam_horiz_vel_diff_mps (a global attribute)
  bit 11: 1 if the theta_s compensation factor can be applied for
   horizontal wind components
  bit 12: 1 if the theta_s compensation factor has been applied to the
   horizontal wind components
  bit 13: 1 if the beam-broadening correction of spectral width results
   in a usable value"

float signal_power (time, range, signal_component_number)

long_name = "Radar return signal power"

units = "dB"

estimated_accuracy = 2.0f

missing_value = -9999.0f

_FillValue = -9999.0f

coordinates = "latitude longitude"

comment = "
  Powers have dimensions of W. The values are uncalibrated and are
stored in dB units, where P_dB = 10.0 * log10(P_linear_units) "

float radial_velocity (time, range, signal_component_number)

standard_name = "radial_velocity_of_scatterers_away_from_instrument"

long_name = "Radial velocity of scatterers away from the radar"

units = "m s-1"

estimated_accuracy = 0.2f

missing_value = -9999.0f

_FillValue = -9999.0f

coordinates = "latitude longitude"

float spectral_width (time, range, signal_component_number)

long_name = "Radar return spectral width"

units = "m s-1"

estimated_accuracy = 0.1f

missing_value = -9999.0f

_FillValue = -9999.0f

coordinates = "latitude longitude"

short first_velocity_bin_number (time, range, signal_component_number)

long_name = "Velocity bin number of the most negative limit of the signal component"

units = "1"

missing_value = -9999s

_FillValue = -9999s

coordinates = "latitude longitude"

comment = "
  The first and final velocity bins of a signal component correspond,
respectively, to its most negative and its most positive Doppler
velocity spectral limits. Numbers are given relative to the
zero velocity velocity-bin such that the corresponding Doppler
velocities are given by the bin numbers multiplied by the spectral
velocity bin spacing. Signal parameters are calculated from the power
spectral densities within these limits, inclusively. Doppler velocity
spectra are cyclic about the Nyquist velocity velocity-bin, whose
number is equal to (either plus or minus) half the number of complex
samples in the discrete Fourier transform. Some signal components are
partially velocity-aliased. These are indicated by quoting the aliased
velocity bin number as if it were extended beyond the Nyquist-velocity
velocity bin, rather than being wrapped around it."

short final_velocity_bin_number (time, range, signal_component_number)

long_name = "(Velocity bin number of the most positive limit of the signal component"

units = "1"

missing_value = -9999s

_FillValue = -9999s

coordinates = "latitude longitude"

comment = "
  The first and final velocity bins of a signal component correspond,
respectively, to its most negative and its most positive Doppler
velocity spectral limits. Numbers are given relative to the
zero velocity velocity-bin such that the corresponding Doppler
velocities are given by the bin numbers multiplied by the spectral
velocity bin spacing. Signal parameters are calculated from the power
spectral densities within these limits, inclusively. Doppler velocity
spectra are cyclic about the Nyquist velocity velocity-bin, whose
number is equal to (either plus or minus) half the number of complex
samples in the discrete Fourier transform. Some signal components are
partially velocity-aliased. These are indicated by quoting the aliased
velocity bin number as if it were extended beyond the Nyquist-velocity
velocity bin, rather than being wrapped around it."

byte peak_smooth_psd_to_noise (time, range, signal_component_number)

long_name = "Peak smoothed signal power spectral density to noise power spectral desnity"

units = "dB"

estimated_accuracy = 2b

missing_value = -99b

_FillValue = -99b

coordinates = "latitude longitude"

comment = "
  Power spectral densities (PSDs) have dimensions of W m-1 s+1. The
values are uncalibrated and stored in dB units, where
  PSD_dB = 10.0 * log10(PSD_linear_units)"

float noise_power (time, range)

long_name = "Spectral noise power"

units = "dB"

estimated_accuracy = 2.0f

missing_value = -9999.0f

_FillValue = -9999.0f

coordinates = "latitude longitude"

comment = "
  Powers have dimensions of W. The values are uncalibrated and are
stored in dB units, where P_dB = 10.0 * log10(P_linear_units) "

byte beam_pointing_direction_number (time)

long_name = "Radar beam pointing direction number"

units = "1"

coordinates = "latitude longitude"

comment = "
  The radar beam can be steered to point in one of 17 possible
directions, represented by an integer between 0 and 16. The variables
beam_pointing_azimuth_angle and beam_pointing_zenith_angle give the
corresponding beam pointing azimuth and zenith angles.
"

float beam_pointing_azimuth_angle (time)

long_name = "Radar beam pointing azimuth angle"

units = "degrees"

coordinates = "latitude longitude"

comment = "
  Possible values are 0.0 degrees for the vertical beam and 27.5 (NE),
72.5 (E), 117.5 (SE), 162.5 (S), 207.5 (SW), 252.5 (W), 297.5 (NW),
and 342.5 (N) degrees for the off-vertical beams. Azimuths are often
referred to by their nominal values (shown in brackets) which differ
by 17.5 degrees clockwise from the true values."

float beam_pointing_zenith_angle (time)

long_name = "Radar beam pointing zenith angle"

units = "degrees"

coordinates = "latitude longitude"

comment = "Possible values are 0.0, 4.2, 6.0, 8.5 and 12.0 degrees."

byte length_of_transmitter_pulse (time)

long_name = "Length of transmitter pulse"

units = "us"

coordinates = "latitude longitude"

comment = "Possible values are 1, 2, 4, 8, 16 and 32 us."

byte sub_length_of_transmitter_pulse (time)

long_name = "Sub-length of transmitter pulse"

units = "us"

coordinates = "latitude longitude"

comment = "Possible values are 1, 2, 4, 8, 16 and 32 us."

short inter_pulse_period (time)

long_name = "Inter pulse period"

units = "us"

coordinates = "latitude longitude"

comment = "Possible values are 80, 160, 320 and 640 us."

short number_of_coherent_integrations (time)

long_name = "Number of coherent integrations"

units = "1"

coordinates = "latitude longitude"

comment = "Possible values are 128, 256, 512 and 1024."

short number_of_complex_samples_in_discrete_fourier_transform (time)

long_name = "Number of samples in the coherently integrated time series"

units = "1"

coordinates = "latitude longitude"

comment = "Possible values are 64, 128, 256, and 512."

byte data_weighting_window_index (time)

long_name = "Data weighting window index"

units = "1"

flag_values = 0 1 2 b

flag_meanings = "rectangular Hanning other"

coordinates = "latitude longitude"

byte number_of_incoherent_integrations (time)

long_name = "Number of incoherent integrations"

units = "1"

coordinates = "latitude longitude"

float spectral_velocity_bin_spacing (time)

long_name = "Spectral velocity bin spacing"

units = "m s-1"

coordinates = "latitude longitude"

byte alternative_profile_details (time)

long_name = "Alternative profile details"

units = "1"

coordinates = "latitude longitude"

comment = "
  These values are for diagnostic purposes only. Details of
alternative profiles identified and selected by the radial continuity
algorithm are coded bit-wise into a 4-bit unsigned integer (albeit
stored as a 16-bit signed integer) for which bit 0 is the least
significant bit:
  bit 3: 1 if interference is detected
  bit 2: 1 if an alternative profile is detected
  bit 1: 1 if the alternative profile is used
  bit 0: 1 if an alternative low-altitude profile is used"

short time_index_of_first_dwell_in_cycle (time)

long_name = "Time index of first dwell in cycle"

units = "1"

coordinates = "latitude longitude"

comment = "
Note that indices are given in C notation, i.e. starting from 0,
rather than in Fortran notation, i.e. starting from 1. "

byte dwell_number (time)

long_name = "Dwell number"

units = "1"

coordinates = "latitude longitude"

comment = "
The dwell number refers to the dwell's position within a cycle. Note
that indices are given in C notation, i.e. starting from 0, rather
than in Fortran notation, i.e. starting from 1. "

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An overview of v3 signal processing

A general description of netCDF file structure.