binietoglou@23: Frequently asked questions binietoglou@23: ========================== binietoglou@23: binietoglou@24: Clouds in the data binietoglou@24: ~~~~~~~~~~~~~~~~~~ binietoglou@23: binietoglou@24: Q: Is it necessary to provide only measurment periods with cloud free conditions and binietoglou@24: homogeneous atmosphere or is this part of ELDA or the pre processing of the data? binietoglou@24: For example in cases with scattered low cumulus clouds. binietoglou@24: binietoglou@24: A: At moment you should provide cloud free data because the automatic cloud screening binietoglou@23: is not yet implemented in the SCC. We are working on this issue and hopefully the new binietoglou@23: module will be implemented at the end of ACTRIS project . binietoglou@23: binietoglou@23: binietoglou@24: High/low range channels binietoglou@24: ~~~~~~~~~~~~~~~~~~~~~~~ binietoglou@24: Q: What is the definition of low range, ultra near range and high range channels? binietoglou@24: Are there any threshold values? binietoglou@24: binietoglou@24: A: There are no threshold values defined for the different range types. This information binietoglou@23: is used only in the gluing procedures just to identify which channel should be taken binietoglou@23: as low range and which one as far range. If no gluing is applied by the SCC the range binietoglou@23: id flags are not taken into account. binietoglou@23: binietoglou@24: Variable depolarization factor binietoglou@24: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ binietoglou@24: binietoglou@24: Q: Due to changes in the settings of our lidarsystem, the depolarization factor can binietoglou@24: change during the measurement. Is it necessary to provide one SCC-file for each settings binietoglou@24: or is it possible to set the Depolarization_Factor variable time dependent? binietoglou@23: binietoglou@24: A: Unfortunately it is not possible to have time dependence on Depolarization_Factor variable. binietoglou@23: So if this parameter changes you should provide different SCC files for each setting. binietoglou@23: binietoglou@24: Extra netcdf parameters binietoglou@24: ~~~~~~~~~~~~~~~~~~~~~~~ binietoglou@24: Q: Is it possible for documentation purposes to put own parameters in the SCC-NetCDF file? binietoglou@24: For example who created the file.... Are there any reasons against this? binietoglou@23: binietoglou@24: A: Technically as long as you use not standard SCC variables for your own parameters there are binietoglou@23: no problems for the SCC. It will just ignore these not standard variables. binietoglou@23: binietoglou@23: binietoglou@24: Netcdf version binietoglou@24: ~~~~~~~~~~~~~~ binietoglou@24: Q: Which NetCDF version is to use? NetCDF3, NetCDF3 Classic, NetCDF4, NetCDF4 Classic? binietoglou@24: binietoglou@24: A: The NetCDF libraries 4.1.3 are used in all the SCC modules. So all the NetCDF formats you binietoglou@23: have indicated should be compatible with the SCC (we have tested NetCDF3 and NetCDF4). binietoglou@23: binietoglou@24: Lidar ratio binietoglou@24: ~~~~~~~~~~~ binietoglou@24: Q: What are the values for the lidar ratio used in the SCC_DB? binietoglou@23: binietoglou@24: A: The values of (fixed) lidar ratio used by the SCC in the elastic retrieval can be set by binietoglou@23: the user using the SCC web interface. In particular you can define a lidar ratio value for binietoglou@24: each elastic backscatter product: in the product page there is the section "Elastic Backscatter binietoglou@24: options" in which there is the field "Fixed lr". In case you want to use a lidar ratio profile binietoglou@23: you should set LR_Input accordingly and provide an external LR profile NetCDF file binietoglou@23: (see documentation on SCC file format). binietoglou@23: binietoglou@24: Calculation of raman and elastic backsatter binietoglou@24: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ binietoglou@24: Q: In cases of measurements where Raman channels are available, the SCC will calculate the Raman binietoglou@24: backscatter profile. If I want to retrieve Klett-retrievals for this channel, too (e.g 532nm) binietoglou@24: is it sufficient to set the value in LR_input(channels) to 1 or 0 plus a LR-profile to get binietoglou@24: both retrievals? binietoglou@23: binietoglou@24: A: No. In general, for each lidar configuration you can define a set of optical products to be calculated binietoglou@23: for that configuration using the SCC web interface. So suppose you have a system with 532nm and 607nm binietoglou@23: channels. In this case you have 2 options: binietoglou@24: binietoglou@24: 1. Raman backscatter and extinction in the e532 file and Raman backscatter (full resolution) in the b532 binietoglou@24: file. In this case you should associate to the configuration a product of type "lidar ratio and will binietoglou@24: produce the e532 file and a product of type "Raman backscatter" which will produce the b532 file binietoglou@24: 2. Raman backscatter and extinction in the e532 file and elastic backscatter in the b532 file. binietoglou@24: In this case you should associate to the configuration a product of type "lidar ratio and extinction" binietoglou@24: which will produce the e532 file and a product of type "elastic backscatter" which will produce the b532 file binietoglou@23: binietoglou@23: Note: you cannot calculate a b532 file containing the Raman and elastic backscatters at the same time. binietoglou@23: The reason is that the 2 products will produce an output file with the same name (according to the EARLINET rules). binietoglou@23: Moreover in general, it makes no sense to calculate the elastic backscatter when you can calculate the Raman binietoglou@23: one which usually is better. binietoglou@23: binietoglou@24: Filename conventions binietoglou@24: ~~~~~~~~~~~~~~~~~~~~ binietoglou@24: A: What are the conventions for the filnames for the various files that need to be uploaded? binietoglou@23: binietoglou@24: Q: The following definitions apply: binietoglou@23: - SCC raw lidar data file binietoglou@23: binietoglou@23: This file should be named as measID.nc. For example if your measurement had a measurementID of 20130101cc00 the corresponding NetCDF file should be named 20130101cc00.nc binietoglou@23: binietoglou@24: Sounding file binietoglou@24: ^^^^^^^^^^^^^ binietoglou@23: binietoglou@23: The file should be named as rs_measID.nc. Considering the above example the sounding file should be named rs_20130101cc00.nc binietoglou@23: binietoglou@23: In this case you should also set the global attribute Sounding_File_Name in the raw lidar data file as: binietoglou@23: binietoglou@23: Sounding_File_Name=rs_20130101cc00.nc binietoglou@23: binietoglou@24: Lidar ratio file binietoglou@24: ^^^^^^^^^^^^^^^^ binietoglou@23: The file should be named as lr_measID.nc. Considering the above example the sounding file should be named lr_20130101cc00.nc binietoglou@23: binietoglou@23: In this case you should also set the global attribute LR_File_Name in the raw lidar data file as: binietoglou@23: binietoglou@23: LR_File_Name=lr_20130101cc00.nc binietoglou@23: binietoglou@24: Overlap file binietoglou@24: ^^^^^^^^^^^^ binietoglou@23: The file should be named as ov_measID.nc. Considering the above example the sounding file should be named ov_20130101cc00.nc binietoglou@23: binietoglou@23: In this case you should also set the global attribute Overlap_File_Name in the raw lidar data file as: binietoglou@23: binietoglou@23: Overalp_File_Name=ov_20130101cc00.nc