html_url,issue_url,id,node_id,user,created_at,updated_at,author_association,body,reactions,performed_via_github_app,issue https://github.com/pydata/xarray/issues/2501#issuecomment-512663861,https://api.github.com/repos/pydata/xarray/issues/2501,512663861,MDEyOklzc3VlQ29tbWVudDUxMjY2Mzg2MQ==,7799184,2019-07-18T04:51:06Z,2019-07-18T04:52:17Z,CONTRIBUTOR,"Hi guys, I'm having some issue that looks similar to @rsignell-usgs. Trying to open 413 netcdf files using `open_mfdataset` with `parallel=True`. The dataset (successfully opened with `parallel=False`) has ~300G on disk and looks like: ```ipython In [1] import xarray as xr In [2]: dset = xr.open_mfdataset(""./bom-ww3/bom-ww3_*.nc"", chunks={'time': 744, 'latitude': 100, 'longitude': 100}, parallel=False) In [3]: dset Out[3]: <xarray.Dataset> Dimensions: (latitude: 190, longitude: 289, time: 302092) Coordinates: * longitude (longitude) float32 70.0 70.4 70.8 71.2 ... 184.4 184.8 185.2 * latitude (latitude) float32 -55.6 -55.2 -54.8 -54.4 ... 19.2 19.6 20.0 * time (time) datetime64[ns] 1979-01-01 ... 2013-05-31T23:00:00.000013440 Data variables: hs (time, latitude, longitude) float32 dask.array<shape=(302092, 190, 289), chunksize=(745, 100, 100)> fp (time, latitude, longitude) float32 dask.array<shape=(302092, 190, 289), chunksize=(745, 100, 100)> dp (time, latitude, longitude) float32 dask.array<shape=(302092, 190, 289), chunksize=(745, 100, 100)> wl (time, latitude, longitude) float32 dask.array<shape=(302092, 190, 289), chunksize=(745, 100, 100)> U10 (time, latitude, longitude) float32 dask.array<shape=(302092, 190, 289), chunksize=(745, 100, 100)> V10 (time, latitude, longitude) float32 dask.array<shape=(302092, 190, 289), chunksize=(745, 100, 100)> hs1 (time, latitude, longitude) float32 dask.array<shape=(302092, 190, 289), chunksize=(745, 100, 100)> hs2 (time, latitude, longitude) float32 dask.array<shape=(302092, 190, 289), chunksize=(745, 100, 100)> tp1 (time, latitude, longitude) float32 dask.array<shape=(302092, 190, 289), chunksize=(745, 100, 100)> tp2 (time, latitude, longitude) float32 dask.array<shape=(302092, 190, 289), chunksize=(745, 100, 100)> lp0 (time, latitude, longitude) float32 dask.array<shape=(302092, 190, 289), chunksize=(745, 100, 100)> lp1 (time, latitude, longitude) float32 dask.array<shape=(302092, 190, 289), chunksize=(745, 100, 100)> lp2 (time, latitude, longitude) float32 dask.array<shape=(302092, 190, 289), chunksize=(745, 100, 100)> th0 (time, latitude, longitude) float32 dask.array<shape=(302092, 190, 289), chunksize=(745, 100, 100)> th1 (time, latitude, longitude) float32 dask.array<shape=(302092, 190, 289), chunksize=(745, 100, 100)> th2 (time, latitude, longitude) float32 dask.array<shape=(302092, 190, 289), chunksize=(745, 100, 100)> hs0 (time, latitude, longitude) float32 dask.array<shape=(302092, 190, 289), chunksize=(745, 100, 100)> tp0 (time, latitude, longitude) float32 dask.array<shape=(302092, 190, 289), chunksize=(745, 100, 100)> ``` Trying to read it on a standard python session gives me core dumped: ```ipython In [1]: import xarray as xr In [2]: dset = xr.open_mfdataset(""./bom-ww3/bom-ww3_*.nc"", chunks={'time': 744, 'latitude': 100, 'longitude': 100}, parallel=True) Bus error (core dumped) ``` Trying to read it on a dask cluster I get: ```ipython In [1]: from dask.distributed import Client In [2]: import xarray as xr In [3]: client = Client() In [4]: dset = xr.open_mfdataset(""./bom-ww3/bom-ww3_*.nc"", chunks={'time': 744, 'latitude': 100, 'longitud ...: e': 100}, parallel=True) free(): double free detected in tcache 2free(): double free detected in tcache 2 free(): double free detected in tcache 2 distributed.nanny - WARNING - Worker process 18744 was killed by signal 11 distributed.nanny - WARNING - Restarting worker distributed.nanny - WARNING - Worker process 18740 was killed by signal 6 distributed.nanny - WARNING - Restarting worker distributed.nanny - WARNING - Worker process 18742 was killed by signal 7 distributed.nanny - WARNING - Worker process 18738 was killed by signal 6 distributed.nanny - WARNING - Restarting worker distributed.nanny - WARNING - Restarting worker free(): double free detected in tcache 2munmap_chunk(): invalid pointer free(): double free detected in tcache 2 free(): double free detected in tcache 2 distributed.nanny - WARNING - Worker process 19082 was killed by signal 6 distributed.nanny - WARNING - Restarting worker distributed.nanny - WARNING - Worker process 19073 was killed by signal 6 distributed.nanny - WARNING - Restarting worker --------------------------------------------------------------------------- KilledWorker Traceback (most recent call last) <ipython-input-4-740561b80fec> in <module>() ----> 1 dset = xr.open_mfdataset(""./bom-ww3/bom-ww3_*.nc"", chunks={'time': 744, 'latitude': 100, 'longitude': 100}, parallel=True) /usr/local/lib/python3.7/dist-packages/xarray/backends/api.py in open_mfdataset(paths, chunks, concat_dim, compat, preprocess, engine, lock, data_vars, coords, combine, autoclose, parallel, **kwargs) 772 # calling compute here will return the datasets/file_objs lists, 773 # the underlying datasets will still be stored as dask arrays --> 774 datasets, file_objs = dask.compute(datasets, file_objs) 775 776 # Combine all datasets, closing them in case of a ValueError /usr/local/lib/python3.7/dist-packages/dask/base.py in compute(*args, **kwargs) 444 keys = [x.__dask_keys__() for x in collections] 445 postcomputes = [x.__dask_postcompute__() for x in collections] --> 446 results = schedule(dsk, keys, **kwargs) 447 return repack([f(r, *a) for r, (f, a) in zip(results, postcomputes)]) 448 /home/oceanum/.local/lib/python3.7/site-packages/distributed/client.py in get(self, dsk, keys, restrictions, loose_restrictions, resources, sync, asynchronous, direct, retries, priority, fifo_timeout, actors, **kwargs) 2525 should_rejoin = False 2526 try: -> 2527 results = self.gather(packed, asynchronous=asynchronous, direct=direct) 2528 finally: 2529 for f in futures.values(): /home/oceanum/.local/lib/python3.7/site-packages/distributed/client.py in gather(self, futures, errors, direct, asynchronous) 1821 direct=direct, 1822 local_worker=local_worker, -> 1823 asynchronous=asynchronous, 1824 ) 1825 /home/oceanum/.local/lib/python3.7/site-packages/distributed/client.py in sync(self, func, asynchronous, callback_timeout, *args, **kwargs) 761 else: 762 return sync( --> 763 self.loop, func, *args, callback_timeout=callback_timeout, **kwargs 764 ) 765 /home/oceanum/.local/lib/python3.7/site-packages/distributed/utils.py in sync(loop, func, callback_timeout, *args, **kwargs) 330 e.wait(10) 331 if error[0]: --> 332 six.reraise(*error[0]) 333 else: 334 return result[0] /usr/lib/python3/dist-packages/six.py in reraise(tp, value, tb) 691 if value.__traceback__ is not tb: 692 raise value.with_traceback(tb) --> 693 raise value 694 finally: 695 value = None /home/oceanum/.local/lib/python3.7/site-packages/distributed/utils.py in f() 315 if callback_timeout is not None: 316 future = gen.with_timeout(timedelta(seconds=callback_timeout), future) --> 317 result[0] = yield future 318 except Exception as exc: 319 error[0] = sys.exc_info() /home/oceanum/.local/lib/python3.7/site-packages/tornado/gen.py in run(self) 733 734 try: --> 735 value = future.result() 736 except Exception: 737 exc_info = sys.exc_info() /home/oceanum/.local/lib/python3.7/site-packages/tornado/gen.py in run(self) 740 if exc_info is not None: 741 try: --> 742 yielded = self.gen.throw(*exc_info) # type: ignore 743 finally: 744 # Break up a reference to itself /home/oceanum/.local/lib/python3.7/site-packages/distributed/client.py in _gather(self, futures, errors, direct, local_worker) 1678 exc = CancelledError(key) 1679 else: -> 1680 six.reraise(type(exception), exception, traceback) 1681 raise exc 1682 if errors == ""skip"": /usr/lib/python3/dist-packages/six.py in reraise(tp, value, tb) 691 if value.__traceback__ is not tb: 692 raise value.with_traceback(tb) --> 693 raise value 694 finally: 695 value = None KilledWorker: ('open_dataset-e7916acb-6d9f-4532-ab76-5b9c1b1a39c2', <Worker 'tcp://10.240.0.5:36019', memory: 0, processing: 63>) ``` Is there anything obviously wrong I'm trying here please? ","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,372848074 https://github.com/pydata/xarray/issues/2501#issuecomment-432546977,https://api.github.com/repos/pydata/xarray/issues/2501,432546977,MDEyOklzc3VlQ29tbWVudDQzMjU0Njk3Nw==,1492047,2018-10-24T07:38:31Z,2018-10-24T07:38:31Z,CONTRIBUTOR,"Thank you for looking into this. I just want to point out that I'm not that much concerned with the ""slow performance"" but much more with the memory consumption and the limitation it implies. ```python from glob import glob import xarray as xr all_files = glob('...*TP110*.nc') display(xr.open_dataset(all_files[0])) display(xr.open_dataset(all_files[1])) ``` ``` <xarray.Dataset> Dimensions: (meas_ind: 40, time: 2871, wvf_ind: 128) Coordinates: * time (time) datetime64[ns] 2017-06-19T14:24:20.792036992 ... 2017-06-19T15:14:38.491743104 * meas_ind (meas_ind) int8 0 1 2 3 4 ... 36 37 38 39 * wvf_ind (wvf_ind) int8 0 1 2 3 ... 125 126 127 lat (time) float64 ... lon (time) float64 ... lon_40hz (time, meas_ind) float64 ... lat_40hz (time, meas_ind) float64 ... Data variables: time_40hz (time, meas_ind) datetime64[ns] ... surface_type (time) float32 ... rad_surf_type (time) float32 ... qual_alt_1hz_range (time) float32 ... qual_alt_1hz_swh (time) float32 ... qual_alt_1hz_sig0 (time) float32 ... qual_alt_1hz_off_nadir_angle_wf (time) float32 ... qual_inst_corr_1hz_range (time) float32 ... qual_inst_corr_1hz_swh (time) float32 ... qual_inst_corr_1hz_sig0 (time) float32 ... qual_rad_1hz_tb_k (time) float32 ... qual_rad_1hz_tb_ka (time) float32 ... alt_state_flag_acq_mode_40hz (time, meas_ind) float32 ... alt_state_flag_tracking_mode_40hz (time, meas_ind) float32 ... orb_state_flag_diode (time) float32 ... orb_state_flag_rest (time) float32 ... ecmwf_meteo_map_avail (time) float32 ... trailing_edge_variation_flag (time) float32 ... trailing_edge_variation_flag_40hz (time, meas_ind) float32 ... ice_flag (time) float32 ... interp_flag_mean_sea_surface (time) float32 ... interp_flag_mdt (time) float32 ... interp_flag_ocean_tide_sol1 (time) float32 ... interp_flag_ocean_tide_sol2 (time) float32 ... interp_flag_meteo (time) float32 ... alt (time) float64 ... alt_40hz (time, meas_ind) float64 ... orb_alt_rate (time) float32 ... range (time) float64 ... range_40hz (time, meas_ind) float64 ... range_used_40hz (time, meas_ind) float32 ... range_rms (time) float32 ... range_numval (time) float32 ... number_of_iterations (time, meas_ind) float32 ... net_instr_corr_range (time) float64 ... model_dry_tropo_corr (time) float32 ... model_wet_tropo_corr (time) float32 ... rad_wet_tropo_corr (time) float32 ... iono_corr_gim (time) float32 ... sea_state_bias (time) float32 ... swh (time) float32 ... swh_40hz (time, meas_ind) float32 ... swh_used_40hz (time, meas_ind) float32 ... swh_rms (time) float32 ... swh_numval (time) float32 ... net_instr_corr_swh (time) float32 ... sig0 (time) float32 ... sig0_40hz (time, meas_ind) float32 ... sig0_used_40hz (time, meas_ind) float32 ... sig0_rms (time) float32 ... sig0_numval (time) float32 ... agc (time) float32 ... agc_rms (time) float32 ... agc_numval (time) float32 ... net_instr_corr_sig0 (time) float32 ... atmos_corr_sig0 (time) float32 ... off_nadir_angle_wf (time) float32 ... off_nadir_angle_wf_40hz (time, meas_ind) float32 ... tb_k (time) float32 ... tb_ka (time) float32 ... mean_sea_surface (time) float64 ... mean_topography (time) float64 ... geoid (time) float64 ... bathymetry (time) float64 ... inv_bar_corr (time) float32 ... hf_fluctuations_corr (time) float32 ... ocean_tide_sol1 (time) float64 ... ocean_tide_sol2 (time) float64 ... ocean_tide_equil (time) float32 ... ocean_tide_non_equil (time) float32 ... load_tide_sol1 (time) float32 ... load_tide_sol2 (time) float32 ... solid_earth_tide (time) float32 ... pole_tide (time) float32 ... wind_speed_model_u (time) float32 ... wind_speed_model_v (time) float32 ... wind_speed_alt (time) float32 ... rad_water_vapor (time) float32 ... rad_liquid_water (time) float32 ... ice1_range_40hz (time, meas_ind) float64 ... ice1_sig0_40hz (time, meas_ind) float32 ... ice1_qual_flag_40hz (time, meas_ind) float32 ... seaice_range_40hz (time, meas_ind) float64 ... seaice_sig0_40hz (time, meas_ind) float32 ... seaice_qual_flag_40hz (time, meas_ind) float32 ... ice2_range_40hz (time, meas_ind) float64 ... ice2_le_sig0_40hz (time, meas_ind) float32 ... ice2_sig0_40hz (time, meas_ind) float32 ... ice2_sigmal_40hz (time, meas_ind) float32 ... ice2_slope1_40hz (time, meas_ind) float64 ... ice2_slope2_40hz (time, meas_ind) float64 ... ice2_mqe_40hz (time, meas_ind) float32 ... ice2_qual_flag_40hz (time, meas_ind) float32 ... mqe_40hz (time, meas_ind) float32 ... peakiness_40hz (time, meas_ind) float32 ... ssha (time) float32 ... tracker_40hz (time, meas_ind) float64 ... tracker_used_40hz (time, meas_ind) float32 ... tracker_diode_40hz (time, meas_ind) float64 ... pri_counter_40hz (time, meas_ind) float64 ... qual_alt_1hz_off_nadir_angle_pf (time) float32 ... off_nadir_angle_pf (time) float32 ... off_nadir_angle_rain_40hz (time, meas_ind) float32 ... uso_corr (time) float64 ... internal_path_delay_corr (time) float64 ... modeled_instr_corr_range (time) float32 ... doppler_corr (time) float32 ... cog_corr (time) float32 ... modeled_instr_corr_swh (time) float32 ... internal_corr_sig0 (time) float32 ... modeled_instr_corr_sig0 (time) float32 ... agc_40hz (time, meas_ind) float32 ... agc_corr_40hz (time, meas_ind) float32 ... scaling_factor_40hz (time, meas_ind) float64 ... epoch_40hz (time, meas_ind) float64 ... width_leading_edge_40hz (time, meas_ind) float64 ... amplitude_40hz (time, meas_ind) float64 ... thermal_noise_40hz (time, meas_ind) float64 ... seaice_epoch_40hz (time, meas_ind) float64 ... seaice_amplitude_40hz (time, meas_ind) float64 ... ice2_epoch_40hz (time, meas_ind) float64 ... ice2_amplitude_40hz (time, meas_ind) float64 ... ice2_mean_amplitude_40hz (time, meas_ind) float64 ... ice2_thermal_noise_40hz (time, meas_ind) float64 ... ice2_slope_40hz (time, meas_ind) float64 ... signal_to_noise_ratio (time) float32 ... waveforms_40hz (time, meas_ind, wvf_ind) float32 ... Attributes: Conventions: CF-1.1 title: GDR - Expertise dataset institution: CNES source: radar altimeter history: 2017-07-21 08:25:07 : Creation contact: CNES aviso@oceanobs.com, EUMETSAT ops@... references: L1 library=V4.5p1, L2 library=V5.5p2, ... processing_center: SALP reference_document: SARAL/ALTIKA Products Handbook, SALP-M... mission_name: SARAL altimeter_sensor_name: ALTIKA radiometer_sensor_name: ALTIKA_RAD doris_sensor_name: DGXX cycle_number: 110 absolute_rev_number: 22545 pass_number: 1 absolute_pass_number: 109219 equator_time: 2017-06-19 14:49:32.128000 equator_longitude: 227.77 first_meas_time: 2017-06-19 14:24:20.792037 last_meas_time: 2017-06-19 15:14:38.491743 xref_altimeter_level1: ALK_ALT_1PaS20170619_154722_20170619_1... xref_radiometer_level1: ALK_RAD_1PaS20170619_154643_20170619_1... xref_altimeter_characterisation: ALK_CHA_AXVCNE20131115_120000_20100101... xref_radiometer_characterisation: ALK_CHR_AXVCNE20110207_180000_20110101... xref_altimeter_ltm: ALK_CAL_AXXCNE20170720_110014_20130102... xref_doris_uso: SRL_OS1_AXXCNE20170720_083800_20130226... xref_orbit_data: SRL_VOR_AXVCNE20170720_111700_20170618... xref_pf_data: SRL_VPF_AXVCNE20170720_111800_20170618... xref_pole_location: SMM_POL_AXXCNE20170721_071500_19870101... xref_gim_data: SRL_ION_AXPCNE20170620_074756_20170619... xref_mog2d_data: SMM_MOG_AXVCNE20170709_191501_20170619... xref_orf_data: SRL_ORF_AXXCNE20170720_083800_20160704... xref_meteorological_files: SMM_APA_AXVCNE20170619_170611_20170619... ellipsoid_axis: 6378136.3 ellipsoid_flattening: 0.0033528131778969 <xarray.Dataset> Dimensions: (meas_ind: 40, time: 2779, wvf_ind: 128) Coordinates: * time (time) datetime64[ns] 2017-06-19T15:14:39.356848 ... 2017-06-19T16:04:56.808873920 * meas_ind (meas_ind) int8 0 1 2 3 4 ... 36 37 38 39 * wvf_ind (wvf_ind) int8 0 1 2 3 ... 125 126 127 lat (time) float64 ... lon (time) float64 ... lon_40hz (time, meas_ind) float64 ... lat_40hz (time, meas_ind) float64 ... Data variables: time_40hz (time, meas_ind) datetime64[ns] ... surface_type (time) float32 ... rad_surf_type (time) float32 ... qual_alt_1hz_range (time) float32 ... qual_alt_1hz_swh (time) float32 ... qual_alt_1hz_sig0 (time) float32 ... qual_alt_1hz_off_nadir_angle_wf (time) float32 ... qual_inst_corr_1hz_range (time) float32 ... qual_inst_corr_1hz_swh (time) float32 ... qual_inst_corr_1hz_sig0 (time) float32 ... qual_rad_1hz_tb_k (time) float32 ... qual_rad_1hz_tb_ka (time) float32 ... alt_state_flag_acq_mode_40hz (time, meas_ind) float32 ... alt_state_flag_tracking_mode_40hz (time, meas_ind) float32 ... orb_state_flag_diode (time) float32 ... orb_state_flag_rest (time) float32 ... ecmwf_meteo_map_avail (time) float32 ... trailing_edge_variation_flag (time) float32 ... trailing_edge_variation_flag_40hz (time, meas_ind) float32 ... ice_flag (time) float32 ... interp_flag_mean_sea_surface (time) float32 ... interp_flag_mdt (time) float32 ... interp_flag_ocean_tide_sol1 (time) float32 ... interp_flag_ocean_tide_sol2 (time) float32 ... interp_flag_meteo (time) float32 ... alt (time) float64 ... alt_40hz (time, meas_ind) float64 ... orb_alt_rate (time) float32 ... range (time) float64 ... range_40hz (time, meas_ind) float64 ... range_used_40hz (time, meas_ind) float32 ... range_rms (time) float32 ... range_numval (time) float32 ... number_of_iterations (time, meas_ind) float32 ... net_instr_corr_range (time) float64 ... model_dry_tropo_corr (time) float32 ... model_wet_tropo_corr (time) float32 ... rad_wet_tropo_corr (time) float32 ... iono_corr_gim (time) float32 ... sea_state_bias (time) float32 ... swh (time) float32 ... swh_40hz (time, meas_ind) float32 ... swh_used_40hz (time, meas_ind) float32 ... swh_rms (time) float32 ... swh_numval (time) float32 ... net_instr_corr_swh (time) float32 ... sig0 (time) float32 ... sig0_40hz (time, meas_ind) float32 ... sig0_used_40hz (time, meas_ind) float32 ... sig0_rms (time) float32 ... sig0_numval (time) float32 ... agc (time) float32 ... agc_rms (time) float32 ... agc_numval (time) float32 ... net_instr_corr_sig0 (time) float32 ... atmos_corr_sig0 (time) float32 ... off_nadir_angle_wf (time) float32 ... off_nadir_angle_wf_40hz (time, meas_ind) float32 ... tb_k (time) float32 ... tb_ka (time) float32 ... mean_sea_surface (time) float64 ... mean_topography (time) float64 ... geoid (time) float64 ... bathymetry (time) float64 ... inv_bar_corr (time) float32 ... hf_fluctuations_corr (time) float32 ... ocean_tide_sol1 (time) float64 ... ocean_tide_sol2 (time) float64 ... ocean_tide_equil (time) float32 ... ocean_tide_non_equil (time) float32 ... load_tide_sol1 (time) float32 ... load_tide_sol2 (time) float32 ... solid_earth_tide (time) float32 ... pole_tide (time) float32 ... wind_speed_model_u (time) float32 ... wind_speed_model_v (time) float32 ... wind_speed_alt (time) float32 ... rad_water_vapor (time) float32 ... rad_liquid_water (time) float32 ... ice1_range_40hz (time, meas_ind) float64 ... ice1_sig0_40hz (time, meas_ind) float32 ... ice1_qual_flag_40hz (time, meas_ind) float32 ... seaice_range_40hz (time, meas_ind) float64 ... seaice_sig0_40hz (time, meas_ind) float32 ... seaice_qual_flag_40hz (time, meas_ind) float32 ... ice2_range_40hz (time, meas_ind) float64 ... ice2_le_sig0_40hz (time, meas_ind) float32 ... ice2_sig0_40hz (time, meas_ind) float32 ... ice2_sigmal_40hz (time, meas_ind) float32 ... ice2_slope1_40hz (time, meas_ind) float64 ... ice2_slope2_40hz (time, meas_ind) float64 ... ice2_mqe_40hz (time, meas_ind) float32 ... ice2_qual_flag_40hz (time, meas_ind) float32 ... mqe_40hz (time, meas_ind) float32 ... peakiness_40hz (time, meas_ind) float32 ... ssha (time) float32 ... tracker_40hz (time, meas_ind) float64 ... tracker_used_40hz (time, meas_ind) float32 ... tracker_diode_40hz (time, meas_ind) float64 ... pri_counter_40hz (time, meas_ind) float64 ... qual_alt_1hz_off_nadir_angle_pf (time) float32 ... off_nadir_angle_pf (time) float32 ... off_nadir_angle_rain_40hz (time, meas_ind) float32 ... uso_corr (time) float64 ... internal_path_delay_corr (time) float64 ... modeled_instr_corr_range (time) float32 ... doppler_corr (time) float32 ... cog_corr (time) float32 ... modeled_instr_corr_swh (time) float32 ... internal_corr_sig0 (time) float32 ... modeled_instr_corr_sig0 (time) float32 ... agc_40hz (time, meas_ind) float32 ... agc_corr_40hz (time, meas_ind) float32 ... scaling_factor_40hz (time, meas_ind) float64 ... epoch_40hz (time, meas_ind) float64 ... width_leading_edge_40hz (time, meas_ind) float64 ... amplitude_40hz (time, meas_ind) float64 ... thermal_noise_40hz (time, meas_ind) float64 ... seaice_epoch_40hz (time, meas_ind) float64 ... seaice_amplitude_40hz (time, meas_ind) float64 ... ice2_epoch_40hz (time, meas_ind) float64 ... ice2_amplitude_40hz (time, meas_ind) float64 ... ice2_mean_amplitude_40hz (time, meas_ind) float64 ... ice2_thermal_noise_40hz (time, meas_ind) float64 ... ice2_slope_40hz (time, meas_ind) float64 ... signal_to_noise_ratio (time) float32 ... waveforms_40hz (time, meas_ind, wvf_ind) float32 ... Attributes: Conventions: CF-1.1 title: GDR - Expertise dataset institution: CNES source: radar altimeter history: 2017-07-21 08:25:19 : Creation contact: CNES aviso@oceanobs.com, EUMETSAT ops@... references: L1 library=V4.5p1, L2 library=V5.5p2, ... processing_center: SALP reference_document: SARAL/ALTIKA Products Handbook, SALP-M... mission_name: SARAL altimeter_sensor_name: ALTIKA radiometer_sensor_name: ALTIKA_RAD doris_sensor_name: DGXX cycle_number: 110 absolute_rev_number: 22546 pass_number: 2 absolute_pass_number: 109220 equator_time: 2017-06-19 15:39:46.492000 equator_longitude: 35.21 first_meas_time: 2017-06-19 15:14:39.356848 last_meas_time: 2017-06-19 16:04:56.808874 xref_altimeter_level1: ALK_ALT_1PaS20170619_154722_20170619_1... xref_radiometer_level1: ALK_RAD_1PaS20170619_154643_20170619_1... xref_altimeter_characterisation: ALK_CHA_AXVCNE20131115_120000_20100101... xref_radiometer_characterisation: ALK_CHR_AXVCNE20110207_180000_20110101... xref_altimeter_ltm: ALK_CAL_AXXCNE20170720_110014_20130102... xref_doris_uso: SRL_OS1_AXXCNE20170720_083800_20130226... xref_orbit_data: SRL_VOR_AXVCNE20170720_111700_20170618... xref_pf_data: SRL_VPF_AXVCNE20170720_111800_20170618... xref_pole_location: SMM_POL_AXXCNE20170721_071500_19870101... xref_gim_data: SRL_ION_AXPCNE20170620_074756_20170619... xref_mog2d_data: SMM_MOG_AXVCNE20170709_191501_20170619... xref_orf_data: SRL_ORF_AXXCNE20170720_083800_20160704... xref_meteorological_files: SMM_APA_AXVCNE20170619_170611_20170619... ellipsoid_axis: 6378136.3 ellipsoid_flattening: 0.0033528131778969```","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,372848074