comparison: docs/faq/faq.rst
docs/faq/faq.rst
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| 1 Frequently asked questions | |
| 2 ========================== | |
| 3 | |
| 4 Is it necessary to provide only measurment periods with cloud free conditions and | |
| 5 homogeneous atmosphere or is this part of ELDA or the pre processing of the data? | |
| 6 For example in cases with scattered low cumulus clouds. | |
| 7 | |
| 8 At moment you should provide cloud free data because the automatic cloud screening | |
| 9 is not yet implemented in the SCC. We are working on this issue and hopefully the new | |
| 10 module will be implemented at the end of ACTRIS project . | |
| 11 | |
| 12 What is the definition of low range, ultra near range and high range channels? | |
| 13 Are there any threshold values? | |
| 14 | |
| 15 There are no threshold values defined for the different range types. This information | |
| 16 is used only in the gluing procedures just to identify which channel should be taken | |
| 17 as low range and which one as far range. If no gluing is applied by the SCC the range | |
| 18 id flags are not taken into account. | |
| 19 | |
| 20 Due to changes in the settings of our lidarsystem, the depolarization factor can | |
| 21 change during the measurement. Is it necessary to provide one SCC-file for each settings | |
| 22 or is it possible to set the Depolarization_Factor variable time dependent? | |
| 23 | |
| 24 Unfortunately it is not possible to have time dependence on Depolarization_Factor variable. | |
| 25 So if this parameter changes you should provide different SCC files for each setting. | |
| 26 | |
| 27 Is it possible for documentation purposes to put own parameters in the SCC-NetCDF file? | |
| 28 For example who created the file.... Are there any reasons against this? | |
| 29 | |
| 30 Technically as long as you use not standard SCC variables for your own parameters there are | |
| 31 no problems for the SCC. It will just ignore these not standard variables. | |
| 32 | |
| 33 Which NetCDF version is to use? NetCDF3, NetCDF3 Classic, NetCDF4, NetCDF4 Classic? | |
| 34 | |
| 35 The NetCDF libraries 4.1.3 are used in all the SCC modules. So all the NetCDF formats you | |
| 36 have indicated should be compatible with the SCC (we have tested NetCDF3 and NetCDF4). | |
| 37 | |
| 38 What are the values for the lidar ratio used in the SCC_DB? | |
| 39 | |
| 40 The values of (fixed) lidar ratio used by the SCC in the elastic retrieval can be set by | |
| 41 the user using the SCC web interface. In particular you can define a lidar ratio value for | |
| 42 each elastic backscatter product: in the product page there is the section “Elastic Backscatter | |
| 43 options” in which there is the field “Fixed lr”. In case you want to use a lidar ratio profile | |
| 44 you should set LR_Input accordingly and provide an external LR profile NetCDF file | |
| 45 (see documentation on SCC file format). | |
| 46 | |
| 47 In cases of measurements where Raman channels are available, the SCC will calculate the Raman | |
| 48 backscatter profile. If I want to retrieve Klett-retrievals for this channel, too (e.g 532nm) | |
| 49 is it sufficient to set the value in LR_input(channels) to 1 or 0 plus a LR-profile to get | |
| 50 both retrievals? | |
| 51 | |
| 52 No. In general, for each lidar configuration you can define a set of optical products to be calculated | |
| 53 for that configuration using the SCC web interface. So suppose you have a system with 532nm and 607nm | |
| 54 channels. In this case you have 2 options: | |
| 55 #. Raman backscatter and extinction in the e532 file and Raman backscatter (full resolution) in the b532 | |
| 56 file. In this case you should associate to the configuration a product of type “lidar ratio and will | |
| 57 produce the e532 file and a product of type “Raman backscatter” which will produce the b532 file | |
| 58 #. Raman backscatter and extinction in the e532 file and elastic backscatter in the b532 file. | |
| 59 In this case you should associate to the configuration a product of type “lidar ratio and extinction” | |
| 60 which will produce the e532 file and a product of type “elastic backscatter” which will produce the b532 file | |
| 61 | |
| 62 Note: you cannot calculate a b532 file containing the Raman and elastic backscatters at the same time. | |
| 63 The reason is that the 2 products will produce an output file with the same name (according to the EARLINET rules). | |
| 64 Moreover in general, it makes no sense to calculate the elastic backscatter when you can calculate the Raman | |
| 65 one which usually is better. | |
| 66 | |
| 67 What are the conventions for the filnames for the various files that need to be uploaded? | |
| 68 | |
| 69 The following definitions apply: | |
| 70 - SCC raw lidar data file | |
| 71 | |
| 72 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 | |
| 73 | |
| 74 - Sounding file | |
| 75 | |
| 76 The file should be named as rs_measID.nc. Considering the above example the sounding file should be named rs_20130101cc00.nc | |
| 77 | |
| 78 In this case you should also set the global attribute Sounding_File_Name in the raw lidar data file as: | |
| 79 | |
| 80 Sounding_File_Name=rs_20130101cc00.nc | |
| 81 | |
| 82 - Lidarration file | |
| 83 | |
| 84 The file should be named as lr_measID.nc. Considering the above example the sounding file should be named lr_20130101cc00.nc | |
| 85 | |
| 86 In this case you should also set the global attribute LR_File_Name in the raw lidar data file as: | |
| 87 | |
| 88 LR_File_Name=lr_20130101cc00.nc | |
| 89 | |
| 90 - Overlap file | |
| 91 | |
| 92 The file should be named as ov_measID.nc. Considering the above example the sounding file should be named ov_20130101cc00.nc | |
| 93 | |
| 94 In this case you should also set the global attribute Overlap_File_Name in the raw lidar data file as: | |
| 95 | |
| 96 Overalp_File_Name=ov_20130101cc00.nc | |
| 97 | |
| 98 | |
| 99 | |
| 100 |
