Mercurial > public > sccdocs / changeset

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