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.
There are 3 different L3 file types:
- L3 default file: This file contains L3 data that uses the default preset for a live plot.
- L3 custom file: This file contains L3 data that uses a custom preset for a live plot.
- L3 archive file: This file contains L3 data from archive plots.
NetCDF L3 filenames have the formats that are shown in the following table.
| L3 File Type | Filename |
|---|---|
| L3 with default profile settings | L3_DEFAULT_<STATION_NUMBER>_YYYYMMDDHHMM_<ParameterKey>_<FREE_FORMAT>.nc |
| L3 with custom profile settings | L3_CUSTOM_<STATION_NUMBER>_YYYYMMDDHHMM_<ParameterKey>_<FREE_FORMAT>.nc |
| L3 for archive plot | L3_OFFLINE_<STATION_NUMBER>_YYYYMMDDHHMM_<ParameterKey>_<FREE_FORMAT>.nc |
| Name | Description |
|---|---|
| L3 | Identification of the data level |
| DEFAULT | Identification of the L3 file type |
| CUSTOM | |
| OFFLINE | |
| 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. |
| FREE_FORMAT | File suffix, if defined in . |
Example filename: L3_DEFAULT_06610_201701160000_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 |
0 = no 1 = yes |
| 360 |
Height averaging interval (Automatic: Max. height averaging interval) |
The default value is 360 m (1181 ft). |
| 1 |
Automatic time averaging |
0 = no 1 = yes |
| 3120 |
Time averaging interval in s (Automatic: Max. time averaging interval in s) |
The available range is 60 ... 3000 seconds. The default value is 3000. |
| 10 |
Algorithm sensitivity |
The available range is 0 … 20. The default value is 5. |
| 30 |
Boundary layer min |
The available range is 30 … 500 m (99 … 1640 ft). The default value is 30 m (99 ft). |
| 4000 |
Boundary layer max |
The available range is 200 … 4000 m (656 ... 13 120 ft). The default value is 4000 m (13 120 ft). |
| 3 |
Number of boundary layers |
The available range is 1 … 3. The default value is 3. |
| 0 |
Algorithm method |
0 = merged 1 = gradient 2 = profile fit |
| Profile fit settings | Profile fit settings | |
|
1 |
SNR |
The available range is 0 … 100. The default value is 1. |
|
500 |
SNR average window |
The available range is 20 … 1000 m (66 ... 3280 ft). The default value is 500 m (1640 ft). |
|
1000 |
Night profile length |
The available range is 10 … 4500 m (33 ... 14 760 ft). The default value is 1000 m (3280 ft). |
|
4000 |
Day profile length |
The available range is 10 … 4500 m (33 ... 14 760 ft). The default value is 4000 m (13 120 ft). |
|
60 |
Outlier removal strength |
The available range is 0 … 500. The default value is 60. |
The L1 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 = one cloud layer 2 = two cloud layers or full obscuration (vertical visibility and highest signal detected) 3 = three 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_profile_range | Dimension = timeDim | Range in meters to which the extinction coefficient (EC) profile data is valid. Above that range data is 0 |
| int | Ec_profile_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 3. |
| 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 |
|---|
| site_location |