The netCDF L3 data file contains level 3 (L3) data that has gone through the calculation service and includes all the data from the algorithms, including mixing layer height values and quality index data.
The file contains L3 data from archive plots.
The netCDF filename is the following.
L3_OFFLINE_<STATION_NUMBER>_YYYYMMDDHHMM_<ParameterKey>.nc
| Name | Description |
|---|---|
| L3 | Identification of the data level |
| OFFLINE | Identification of the L3 file type |
| STATION_NUMBER | WMO station number, if defined in . |
| YYYYMMDDHHMM | UTC time |
| ParameterKey | Identification of the advanced algorithm settings. See the table below for an explanation. |
Example filename:
L3_OFFLINE__202311290056_1_360_1_3120_10_30_4000_3_0_1_500_1000_4000_60.nc
Example parameter key:
1_360_1_3120_10_30_4000_3_0_1_500_1000_4000_60| Example value | Description | Value/Range |
|---|---|---|
| 1 |
Automatic height averaging |
1 = yes |
| 360 |
Height averaging interval (Automatic: Max. height averaging interval) |
The default value is 360 m (1181 ft). |
| 1 |
Automatic time averaging |
1 = yes |
| 3120 |
Time averaging interval in s (Automatic: Max. time averaging interval in s) |
The default value is 3000. |
| 10 |
Algorithm sensitivity |
The default value is 5. |
| 30 |
Boundary layer min |
The default value is 30 m (99 ft). |
| 4000 |
Boundary layer max |
The default value is 4000 m (13 120 ft). |
| 3 |
Number of boundary layers |
The default value is 3. |
| 0 |
Algorithm method |
0 = merged |
| Profile fit settings | Profile fit settings | |
|
1 |
SNR |
The default value is 1. |
|
500 |
SNR average window |
The default value is 500 m (1640 ft). |
|
1000 |
Night profile length |
The default value is 1000 m (3280 ft). |
|
4000 |
Day profile length |
The default value is 4000 m (13 120 ft). |
|
60 |
Outlier removal strength |
The default value is 60. |
The L3 files contain the following dimension, variable, and global attribute information.
| Dimension | Description |
|---|---|
| timeDim | Number of profiles |
| nameDim | − |
| date_stampDim | − |
| message_typeDim | − |
| periodDim | − |
| Mean_Layer_HeightDim | − |
| Mean_Layer_QualityIndexDim | − |
| Mean_Layer_Calculation_TimeDim | − |
| cloud_statusDim | − |
| cloud_dataDim | − |
| bl_height_lengthDim | − |
| bl_indexDim | − |
| bl_heightDim | − |
| Bs_prof_lengthDim | − |
| Ng_prof_lengthDim | − |
| Ec_prof_lengthDim | − |
| Ec_prof_rangeDim | − |
| Ec_prof_opacityDim | − |
| vrb_height_averagingDim | − |
| vrb_time_averagingDim | − |
| Height_averaging_paramDim | − |
| Time_averaging_periodDim | − |
| algorithm_sensitivityDim | − |
| boundary_layer_minDim | − |
| boundary_layer_maxDim | − |
| number_of_boundary_layersDim | − |
| Location_latitudeDim | − |
| Location_longitudeDim | − |
| Location_altitudeDim | − |
| location_utc_offsetDim | − |
| Algorithm_MethodDim | − |
| parameter_keyDim | − |
| sunrise_utcDim | − |
| sunset_utcDim | − |
| LevelTwoCountDim | − |
| range | Number of vertical bins |
| Type | Variable | Attributes | Description |
|---|---|---|---|
| int | time |
Units = seconds since 1970-01-01 00:00:00.000 Type = double Dimension = time axis = T |
Unix time |
| string | name | Dimension = timeDim | Data identifier (ceilometer name) as defined in |
| string | date_stamp | Dimension = timeDim |
Measurement timestamp in textual form (yyyy-mm-dd hh:mm:ss) |
| int | message_type | Dimension = timeDim | Ceilometer data message type |
| int | period | Dimension = timeDim | Sending frequency of ceilometer data message in seconds |
| int | Mean_Layer_Height | Dimension = timeDim | Average mixing layer height for the period of 1 hour |
| int | Mean_Layer_QualityIndex | Dimension = timeDim | Average mixing layer quality index for the period of 1 hour |
| int | Mean_Layer_Calculation_Time | Dimension = timeDim | Average layer calculation time for the 1-hour interval |
| int | cloud_status | Dimension = timeDim |
0 = no significant backscatter/some obscuration but determined to be transparent 1 = 1 cloud layer 2 = 2 cloud layers or full obscuration (vertical visibility and highest signal detected) 3 = 3 cloud layers |
| int | cloud_data | Dimension = timeDim | Cloud bases or vertical visibility/highest signal detected (meters or feet) |
| int | bl_height_length | Dimension = timeDim | Number of boundary layer height candidates found (0–3) |
| int | bl_index | Dimension = timeDim | Quality indices for boundary layer height candidates |
| int | bl_height | Dimension = timeDim | Boundary layer height candidates (meters) |
| int | Bs_profile_length | Dimension = timeDim | Number of samples in ceilometer signal backscatter profile (450) |
| int | Bs_profile_data | Dimension = timeDim, range |
Ceilometer signal backscatter profile in units of 10-9 m-1 sr-1 (10-m / 33-ft resolution, 450 samples up to height of 4500 m / 14 764 ft) |
| int | Ng_profile_length | Dimension = timeDim | Number of samples in negative gradient profile (450) |
| int | Ng_profile_data | Dimension = timeDim, range | Negative gradient profile (10-m / 33-ft resolution, 450 samples up to height of 4500 m / 14 764 ft) |
| int | Ec_profile_length | Dimension = timeDim | Number of samples in ceilometer signal extinction coefficient profile (450) |
| int | Ec_profile_data | Dimension = timeDim, range |
Extinction coefficient (EC) profile in units of 10-4 m-1 (10-m / 33-ft resolution, 450 samples up to height of 4500 m / 14 764 ft) |
| int | Ec_prof_range | Dimension = timeDim | Range in meters to which the extinction coefficient (EC) profile data is valid. Above that range data is 0 |
| int | Ec_prof_opacity | Dimension = timeDim | Opacity (or aerosol optical depth, AOD) of the extinction coefficient (EC) profile in units of 0.01; it is the integral of EC up to that range |
| int | vrb_height_averaging | Dimension = timeDim |
1 = True, variable height averaging (default) 0 = False, user-defined constant height averaging |
| int | vrb_time_averaging | Dimension = timeDim |
1 = True, variable time averaging (default) 0 = False, user-defined constant time averaging |
| int | Height_averaging_param | Dimension = timeDim |
Height averaging parameter (40–600 m, default 360 m / 131–1969 ft, default 1181 ft) Used only if vrb_height_averaging = false |
| int | Time_averaging_period | Dimension = timeDim |
Time averaging period (60–3000 seconds, default 3000) Used only if vrb_time_averaging = false |
| int | algorithm_sensitivity | Dimension = timeDim |
Algorithm sensitivity (0–20, default 10) Smaller value means higher sensitivity |
| int | boundary_layer_min | Dimension = timeDim | Minimum height for a boundary layer height candidate (30–500 m, default 30 m / 99–1640 ft, default 99 ft) |
| int | boundary_layer_max | Dimension = timeDim | Maximum height for a boundary layer height candidate (200–4000 m, default 4000 / 656–13 123 ft, default 13 123 ft) |
| int | number_of_boundary_layers | Dimension = timeDim | Maximum number of boundary layer height candidates to be reported (1–3, default 3) |
| float | location_latitude | Dimension = timeDim | Latitude of measurement site. Based on ceilometer location as defined in |
| float | location_longitude | Dimension = timeDim | Longitude of measurement site. Based on ceilometer location as defined in |
| float | location_altitude | Dimension = timeDim | Altitude of measurement site. Based on ceilometer altitude as defined in |
| float | location_utc_offset | Dimension = timeDim | UTC offset of each measurement. Based on ceilometer location as defined in |
| int | Algorithm_Method | Dimension = timeDim |
0 = Merged gradient and profile fit 1 = Gradient 2 = Profile fit |
| string | parameter_key | Dimension = timeDim | See Table 2. |
| float | sunrise_utc | Dimension = timeDim | UTC sunrise time in hours |
| float | sunset_utc | Dimension = timeDim | UTC sunset time in hours |
| int | LevelTwoCount | Dimension = timeDim | Number of level 2 (L2) samples used to create level 3 (L3) sample |
| int | range | Dimension = range | 4500 m (14 764 ft), values with 10 m (33 ft) resolution meaning 450 samples |
| Attribute | Description |
|---|---|
| site_location | Device name from BL-View device settings |