Operating Manual CHM 8k
R1.7 / 01-2020
Communication via RS485 & Ethernet
40
Length of data file names
For problem-free file transfer, the ISO standards should be complied with in their
extended form. The file length should not exceed 31 characters. For the structure of
the day files with [Date]_[Location]_[DeviceID]_[Index].nc (8_5_9_3.2=31 characters),
this means that the variable “location” must have less than 6 characters.
8.4.4 Format structure
In the NetCDF format, the values to be stored are defined and stored by dimensions, variables and
attributes. Table 13
to Table 15
describe the designations used.
Dimensions
Dimension
Description
Standard
time
Number of measured backscatter profiles within a NetCDF file
UNLIMITED
range
Number of points measured and stored in backscatter profiles in the
NetCDF format with a resolution of 15 m.
667
range_hr
Number of points stored in the high-resolution NetCDF backscatter
profile with a resolution of 5 m
32
layer
Number of cloud layers transmitted in telegrams and stored in
NetCDF files
3
Table 13 Dimensions in NetCDF.
Global attributes
Attribute
Description
Type
title
Heading for graphical representation, e.g. “Lufft Berlin, CHM 8k”
text
source
See device_name (left for compatibility reasons)
text
device_name
Serial number, device name of the instrument
text
serlom
Serial number of the measuring unit, e.g.
“TUB198001”
text
day
Day of the month, on which the data was recorded
int
month
Month as a number, January = 1,…
int
year
Year, in which the data were recorded: e.g. 2019
int
location*
Location / site of measurement
text
Institution*
Institution or company
text
wmo_id*
WMO station ID
int
software_version Linux kernel, FPGA software, Firmware
text
Comment*
Any descriptive comment
text
overlap_file
Name / time of the overlap correction function used to generate
the beta variables
text
Table 14 Global attributes in NetCDF.
*
User-defined settings