Sun, 23 Oct 2016 23:12:51 +0300
Depolarization draft docs.
ulalume3@67 | 1 | **Single Calculus Chain ** |
ulalume3@67 | 2 | |
ulalume3@67 | 3 | **version: 4.0** |
ulalume3@67 | 4 | |
ulalume3@67 | 5 | **date: Date (fixed)** |
ulalume3@67 | 6 | |
ulalume3@67 | 7 | **DRAFT** |
ulalume3@67 | 8 | |
ulalume3@67 | 9 | This document describes the main changes implemented in the SCC v4.0 |
ulalume3@67 | 10 | with respect to what already provided in the SCC v3.11. It will be also |
ulalume3@67 | 11 | reported the modifications the users need to perform to run the new |
ulalume3@67 | 12 | version of SCC. |
ulalume3@67 | 13 | |
ulalume3@67 | 14 | Table of Contents |
ulalume3@67 | 15 | |
ulalume3@67 | 16 | 1. Particle Linear Depolarization Ratio Implementation 3 |
ulalume3@67 | 17 | |
ulalume3@67 | 18 | 1.1 Background 3 |
ulalume3@67 | 19 | |
ulalume3@67 | 20 | 1.2 Polarization calibration 4 |
ulalume3@67 | 21 | |
ulalume3@67 | 22 | 1.3 SCC procedure to calculate the PLDRP 4 |
ulalume3@67 | 23 | |
ulalume3@67 | 24 | 2.Changes of the SCC input format 8 |
ulalume3@67 | 25 | |
ulalume3@67 | 26 | 3.Real Example 10 |
ulalume3@67 | 27 | |
ulalume3@67 | 28 | 3.1 Modification of polarization channel parameters 10 |
ulalume3@67 | 29 | |
ulalume3@67 | 30 | 3.2 Definition of new calibration configuration and product 12 |
ulalume3@67 | 31 | |
ulalume3@67 | 32 | 3.3 Definition of “Raman/Elastic backscatter and linear depolarization |
ulalume3@67 | 33 | ratio” 16 |
ulalume3@67 | 34 | |
ulalume3@67 | 35 | Particle Linear Depolarization Ratio Implementation |
ulalume3@67 | 36 | =================================================== |
ulalume3@67 | 37 | |
ulalume3@67 | 38 | The most important improvement included in the SCC v4.0 is the |
ulalume3@67 | 39 | implementation of a new optical product which is the particle linear |
ulalume3@67 | 40 | depolarization ratio. |
ulalume3@67 | 41 | |
ulalume3@67 | 42 | **Background** |
ulalume3@67 | 43 | -------------- |
ulalume3@67 | 44 | |
ulalume3@67 | 45 | The calculation of the volume linear depolarization ratio profile |
ulalume3@67 | 46 | (*VLDR*) and particle linear depolarization ratio profile (*PLDR*) needs |
ulalume3@67 | 47 | two different steps: |
ulalume3@67 | 48 | |
ulalume3@67 | 49 | 1. the calibration of the polarization sensitive lidar channels; |
ulalume3@67 | 50 | |
ulalume3@67 | 51 | 2. the calculation of the *VLDR* or *PLDR* itself. |
ulalume3@67 | 52 | |
ulalume3@67 | 53 | The SCC allows the user to make both the above points. In particular the |
ulalume3@67 | 54 | calibration step is made by a completely new module called |
ulalume3@67 | 55 | **scc\_calibrator** which computes the *apparent calibration factor* |
ulalume3@67 | 56 | h\ :sup:`\*` out of the pre-processed data provided by the standard |
ulalume3@67 | 57 | **ELPP** (Earlinet Lidar Pre-Processor) module and it records it in the |
ulalume3@67 | 58 | SCC database (SCC\_DB). Once logged into the SCC\_DB this factor can be |
ulalume3@67 | 59 | used whenever it is necessary. |
ulalume3@67 | 60 | |
ulalume3@67 | 61 | The raw lidar calibration measurements should be put in a NetCDF file |
ulalume3@67 | 62 | which has the same structure as the “standard” raw SCC NetCDF input file |
ulalume3@67 | 63 | (for more details see sections 2 and 3.2). |
ulalume3@67 | 64 | |
ulalume3@67 | 65 | New signal types have been introduced to take into account special |
ulalume3@67 | 66 | channel configurations used for calibration purposes. |
ulalume3@67 | 67 | |
ulalume3@67 | 68 | Moreover new product types for both calibration and *PLDR* calculation |
ulalume3@67 | 69 | have been defined. As, in principle, it is possible to calculate the |
ulalume3@67 | 70 | *PLDR* only when the aerosol backscatter coefficient profile is |
ulalume3@67 | 71 | available the following new products have been defined: |
ulalume3@67 | 72 | |
ulalume3@67 | 73 | 1. *Linear polarization calibration (factor* h) *(product\_type\_id=6);* |
ulalume3@67 | 74 | |
ulalume3@67 | 75 | 2. *Raman backscatter and linear depolarization ratio |
ulalume3@67 | 76 | (product\_type\_id=7);* |
ulalume3@67 | 77 | |
ulalume3@67 | 78 | 3. *Elastic backscatter and linear depolarization ratio |
ulalume3@67 | 79 | (product\_type\_id=8).* |
ulalume3@67 | 80 | |
ulalume3@67 | 81 | The first product in the above list is used only for calibration while |
ulalume3@67 | 82 | the other two are used for the calculation of *PLDR*. Basically, in most |
ulalume3@67 | 83 | of the cases, the products 2 and 3 are equivalent to the corresponding |
ulalume3@67 | 84 | backscatter product types with the exception that also the following new |
ulalume3@67 | 85 | variables are available: |
ulalume3@67 | 86 | |
ulalume3@67 | 87 | double VolumeDepol(Length) ; |
ulalume3@67 | 88 | |
ulalume3@67 | 89 | double ErrorVolumeDepol(Length) ; |
ulalume3@67 | 90 | |
ulalume3@67 | 91 | ErrorVolumeDepol:long\_name = "absolute error of VolumeDepol" ; |
ulalume3@67 | 92 | |
ulalume3@67 | 93 | double ParticleDepol(Length) ; |
ulalume3@67 | 94 | |
ulalume3@67 | 95 | double ErrorParticleDepol(Length) ; |
ulalume3@67 | 96 | |
ulalume3@67 | 97 | ErrorParticleDepol:long\_name = "absolute error of ParticleDepol" ; |
ulalume3@67 | 98 | |
ulalume3@67 | 99 | **Polarization calibration** |
ulalume3@67 | 100 | ---------------------------- |
ulalume3@67 | 101 | |
ulalume3@67 | 102 | An important point is the definition of reliable *PLDR* calibration |
ulalume3@67 | 103 | procedures. Within EARLINET the following calibration procedures are |
ulalume3@67 | 104 | currently used: |
ulalume3@67 | 105 | |
ulalume3@67 | 106 | a) Rayleigh calibration; |
ulalume3@67 | 107 | |
ulalume3@67 | 108 | b) +45 calibration method, or D90 calibration method (made by +45 and |
ulalume3@67 | 109 | -45 measurements); |
ulalume3@67 | 110 | |
ulalume3@67 | 111 | c) 3 signals (total, cross and parallel). |
ulalume3@67 | 112 | |
ulalume3@67 | 113 | It is well known that method a) could produce easily large errors on |
ulalume3@67 | 114 | *PLDR* which cannot be controlled. For this reason only the methods b) |
ulalume3@67 | 115 | and c) can be used to provide reliable polarization calibrations and so |
ulalume3@67 | 116 | only those methods will be implemented in the SCC. |
ulalume3@67 | 117 | |
ulalume3@67 | 118 | For what it concerns the method c) it, basically, requires to solve the |
ulalume3@67 | 119 | equation: |
ulalume3@67 | 120 | |
ulalume3@67 | 121 | in two different of atmospheric layers with considerably different |
ulalume3@67 | 122 | *VLDR*. So to calibrate in this way the implementation of automatic |
ulalume3@67 | 123 | layer identification in the SCC is required. As at moment this feature |
ulalume3@67 | 124 | is not yet available within the SCC *ONLY* the method b) is considered. |
ulalume3@67 | 125 | |
ulalume3@67 | 126 | SCC procedure to calculate the PLDRP |
ulalume3@67 | 127 | ------------------------------------ |
ulalume3@67 | 128 | |
ulalume3@67 | 129 | According to what mentioned before the SCC calculates the *PLDR* through |
ulalume3@67 | 130 | the following steps: |
ulalume3@67 | 131 | |
ulalume3@67 | 132 | 1. The user needs to create a new system configuration in the SCC\_DB |
ulalume3@67 | 133 | including only lidar channels used for the calibration. One (or more) |
ulalume3@67 | 134 | *Linear polarization calibration (product\_type\_id=6)* product |
ulalume3@67 | 135 | should be associated to this new configuration (see section 3.2 for |
ulalume3@67 | 136 | more details); |
ulalume3@67 | 137 | |
ulalume3@67 | 138 | 2. This new system configuration should contain only the polarization |
ulalume3@67 | 139 | channels in the configuration used for the calibration (for example |
ulalume3@67 | 140 | rotated in the polarization plane of +45 degrees). A channel in |
ulalume3@67 | 141 | calibration measurement configuration should have a *DIFFERENT* |
ulalume3@67 | 142 | channel ID from the channel ID corresponding to the same channel in |
ulalume3@67 | 143 | standard measurement configuration. For example, if a system has two |
ulalume3@67 | 144 | polarization channels which in standard measurement configuration |
ulalume3@67 | 145 | correspond to the channel ID=1 and 2 respectively, the same physical |
ulalume3@67 | 146 | channels under calibration measurement configuration should |
ulalume3@67 | 147 | correspond to different channel IDs (let's say ID=3 and 4 for the +45 |
ulalume3@67 | 148 | degrees polarization rotated channels and ID=5 and 6 for the -45 |
ulalume3@67 | 149 | degrees polarization rotated ones in case D90 calibration method is |
ulalume3@67 | 150 | used). Moreover, the polarization channels should be labeled |
ulalume3@67 | 151 | correctly using the new signal types available (*+45elPT, +45elPR, |
ulalume3@67 | 152 | -45elPT, -45elPR, +45elPTnr, +45elPTfr, +45elPRnr, +45elPRfr, |
ulalume3@67 | 153 | -45elPTnr, -45elPTfr, -45elPRnr, -45elPRfr).* For more details see |
ulalume3@67 | 154 | section 3.2; |
ulalume3@67 | 155 | |
ulalume3@67 | 156 | 3. In SCC v4.0 the polarization channels are *NOT* labeled on the base |
ulalume3@67 | 157 | of their polarization state (as it was done in the SCC v3.11) but |
ulalume3@67 | 158 | *ALWAYS* as transmitted and reflected channels. So the channels that |
ulalume3@67 | 159 | in SCC v3.11 were labeled as *elCP, elCPnr, elCPfr, elPP, elPPnr |
ulalume3@67 | 160 | elPPfr* will be labeled in SCC v4.0 as *elPR, elPRnr elPRfr elPT, |
ulalume3@67 | 161 | elPTnr elPTfr* where the letter *T* stands from transmitted and the |
ulalume3@67 | 162 | letter *R* for reflected. |
ulalume3@67 | 163 | |
ulalume3@67 | 164 | **WARNING:** In switching from the SCC v3.11 to SCC v4.0 the following |
ulalume3@67 | 165 | modifications have been made on *ALL* channels of *ALL* registered |
ulalume3@67 | 166 | configurations: |
ulalume3@67 | 167 | |
ulalume3@67 | 168 | *elPP→elPR* |
ulalume3@67 | 169 | |
ulalume3@67 | 170 | *elCP→elPT* |
ulalume3@67 | 171 | |
ulalume3@67 | 172 | *elPPnr→elPRnr* |
ulalume3@67 | 173 | |
ulalume3@67 | 174 | *elPPfr→ elPRfr* |
ulalume3@67 | 175 | |
ulalume3@67 | 176 | *elCPnr→ elPTnr* |
ulalume3@67 | 177 | |
ulalume3@67 | 178 | *elCPfr→ elPTfr* |
ulalume3@67 | 179 | |
ulalume3@67 | 180 | Please be sure these modifications reflect to your actual lidar setup |
ulalume3@67 | 181 | (cross channels are transmitted and parallel channels are reflected); |
ulalume3@67 | 182 | |
ulalume3@67 | 183 | 1. The user needs to submit a file (same format as raw SCC input file) |
ulalume3@67 | 184 | containing the raw data for the lidar channels defined at the point 1 |
ulalume3@67 | 185 | (see section 3.2 for more details); |
ulalume3@67 | 186 | |
ulalume3@67 | 187 | 2. The file at point 2 is pre-processed by **ELPP** module which applies |
ulalume3@67 | 188 | the standard pre-processing procedures applied to “standard” lidar |
ulalume3@67 | 189 | data; |
ulalume3@67 | 190 | |
ulalume3@67 | 191 | 3. The pre-processed files are then processed by the new modules |
ulalume3@67 | 192 | **scc\_calibrator** which calculates h\ :sup:`\*` *the apparent |
ulalume3@67 | 193 | calibration factor* and logs it into the SCC\_DB; |
ulalume3@67 | 194 | |
ulalume3@67 | 195 | 4. The user needs to create a new system configuration in the SCC\_DB |
ulalume3@67 | 196 | (which should be different from the one used for the calibration) and |
ulalume3@67 | 197 | associate it the new product *Raman backscatter and linear |
ulalume3@67 | 198 | depolarization ratio (product\_type\_id=7)* or *Elastic backscatter |
ulalume3@67 | 199 | and linear depolarization ratio (product\_type\_id=8).* Alternatively |
ulalume3@67 | 200 | the calculation of those products can be added to an already existing |
ulalume3@67 | 201 | lidar configuration as long as it is different from the calibration |
ulalume3@67 | 202 | one; |
ulalume3@67 | 203 | |
ulalume3@67 | 204 | 5. The product defined at point 5 should be linked to the product |
ulalume3@67 | 205 | containing the polarization calibration (defined at point 1) in a way |
ulalume3@67 | 206 | that the *apparent calibration factor* can be selected from the |
ulalume3@67 | 207 | SCC\_DB (see section 3.3 and in particular figure 3.4); |
ulalume3@67 | 208 | |
ulalume3@67 | 209 | 6. The user needs to submit another SCC raw data file containing the |
ulalume3@67 | 210 | “standard” measurements; |
ulalume3@67 | 211 | |
ulalume3@67 | 212 | 7. Finally **ELPP** and **ELDA** will produce a b-file containing |
ulalume3@67 | 213 | backscatter coefficient profile and *PLDR*. In particular this |
ulalume3@67 | 214 | calculation is made in two different steps: from the pre-processed |
ulalume3@67 | 215 | lidar polarization signals, and taking into account the *apparent |
ulalume3@67 | 216 | calibration factor* and the *calibration factor correction K* |
ulalume3@67 | 217 | (defined as option of *Linear polarization calibration* product\ *)* |
ulalume3@67 | 218 | written into the SCC\_DB, an “apparent” *VLDR* *d\ :sup:`\*`* is |
ulalume3@67 | 219 | calculated. Even if *d\ :sup:`\*`* is a calibrated quantity it can be |
ulalume3@67 | 220 | still affected by possible systematic errors due to not perfect |
ulalume3@67 | 221 | optics or alignment of the system; |
ulalume3@67 | 222 | |
ulalume3@67 | 223 | 8. To take into account these errors a corrected *VLDR* (*d)* is |
ulalume3@67 | 224 | calculated using the *polarization cross-talk correction parameters* |
ulalume3@67 | 225 | *G* and *H* calculated on the base of Müller matrix formalism. These |
ulalume3@67 | 226 | cross-talk correction parameters (*G* and *H*) are stored in the |
ulalume3@67 | 227 | SCC\_DB for each lidar channels (see section 3.1 in particular figure |
ulalume3@67 | 228 | 3.2). Finally the *PLDR* is calculated using the backscatter |
ulalume3@67 | 229 | coefficient profile and the molecular LDRP calculated by ELPP |
ulalume3@67 | 230 | considering the center wavelength and bandwidth of the channels |
ulalume3@67 | 231 | interference filter. |
ulalume3@67 | 232 | |
ulalume3@67 | 233 | The *apparent calibration factor* h\ :sup:`\*` is calculated by the |
ulalume3@67 | 234 | **scc\_calibrator** module as the geometrical mean of the ratio of the |
ulalume3@67 | 235 | +/-45 degrees reflected to the +/- 45 degrees transmitted signals within |
ulalume3@67 | 236 | an altitude calibration range defined by the users in the raw data input |
ulalume3@67 | 237 | files. |
ulalume3@67 | 238 | |
ulalume3@67 | 239 | In case of +45 calibration method h\ :sup:`\*` is calculated by: |
ulalume3@67 | 240 | |
ulalume3@67 | 241 | (1.1) |
ulalume3@67 | 242 | |
ulalume3@67 | 243 | While in case of D90 calibration method: |
ulalume3@67 | 244 | |
ulalume3@67 | 245 | (1.2) |
ulalume3@67 | 246 | |
ulalume3@67 | 247 | **ELDA** module calculates the “apparent” *VLDR*: |
ulalume3@67 | 248 | |
ulalume3@67 | 249 | (1.3) |
ulalume3@67 | 250 | |
ulalume3@67 | 251 | the *VLDR* |
ulalume3@67 | 252 | |
ulalume3@67 | 253 | (1.4) |
ulalume3@67 | 254 | |
ulalume3@67 | 255 | and the *PLDR* |
ulalume3@67 | 256 | |
ulalume3@67 | 257 | (1.5) |
ulalume3@67 | 258 | |
ulalume3@67 | 259 | where: |
ulalume3@67 | 260 | |
ulalume3@67 | 261 | - h\ :sup:`\*` is the *apparent calibration factor* calculated by |
ulalume3@67 | 262 | **scc\_calibrator** |
ulalume3@67 | 263 | |
ulalume3@67 | 264 | - *K* is the *calibration factor correction* defined as polarization |
ulalume3@67 | 265 | product option |
ulalume3@67 | 266 | |
ulalume3@67 | 267 | - *I\ :sub:`T`* and I\ *:sub:`R`* are the transmitted and the reflected |
ulalume3@67 | 268 | signals in the polarization detection set-up |
ulalume3@67 | 269 | |
ulalume3@67 | 270 | - *G\ :sub:`T,R`* and *H\ :sub:`T,R`* are *polarization cross-talk |
ulalume3@67 | 271 | correction parameters* for the transmitted and reflected signals used |
ulalume3@67 | 272 | to correct for systematic errors. Both these factors are defined in |
ulalume3@67 | 273 | the SCC\_DB for each lidar channel. |
ulalume3@67 | 274 | |
ulalume3@67 | 275 | - *d\ :sub:`m`* is the molecular linear depolarization ratio calculated |
ulalume3@67 | 276 | by ELPP |
ulalume3@67 | 277 | |
ulalume3@67 | 278 | - *R* is the backscatter ratio |
ulalume3@67 | 279 | |
ulalume3@67 | 280 | Please note once again that the polarization channels are described in |
ulalume3@67 | 281 | terms of transmitted and reflected signals. This means that according to |
ulalume3@67 | 282 | different lidar instrumental configurations, the transmitted or the |
ulalume3@67 | 283 | reflected channel can contain total, perpendicular or parallel polarized |
ulalume3@67 | 284 | signals. |
ulalume3@67 | 285 | |
ulalume3@67 | 286 | In order to retrieve the backscatter profile the total signal must be |
ulalume3@67 | 287 | obtained combining the transmitted and reflected polarized signals. The |
ulalume3@67 | 288 | following formula is used: |
ulalume3@67 | 289 | |
ulalume3@67 | 290 | (1.6) |
ulalume3@67 | 291 | |
ulalume3@67 | 292 | The formulas above are general and can be adapted to all possible |
ulalume3@67 | 293 | polarization lidar configurations selecting the right polarization |
ulalume3@67 | 294 | cross-talk correction parameters (see Table 1.1). |
ulalume3@67 | 295 | |
ulalume3@67 | 296 | Let's suppose, for example, we have the perpendicular polarized lidar |
ulalume3@67 | 297 | signal on the transmitted channel and the parallel polarized on |
ulalume3@67 | 298 | reflected channel. For an ideal system (no diattenuation and cross-talk) |
ulalume3@67 | 299 | we have: |
ulalume3@67 | 300 | |
ulalume3@67 | 301 | If, on the other hands, we have the perpendicular polarized lidar signal |
ulalume3@67 | 302 | on reflected channel and the total polarized on the transmitted for and |
ulalume3@67 | 303 | ideal system we have: |
ulalume3@67 | 304 | |
ulalume3@67 | 305 | **Table 1.1:** Polarization cross-talk correction parameters for ideal |
ulalume3@67 | 306 | systems |
ulalume3@67 | 307 | |
ulalume3@67 | 308 | +----------------------+-----------------------------+-----------------+-----------------+-----------------+ |
ulalume3@67 | 309 | | Laser polarization | Detected in lidar channel | |
ulalume3@67 | 310 | +----------------------+-----------------------------+-----------------+-----------------+-----------------+ |
ulalume3@67 | 311 | | | Transmitted | Reflected | |
ulalume3@67 | 312 | +----------------------+-----------------------------+-----------------+-----------------+-----------------+ |
ulalume3@67 | 313 | | | *G\ :sub:`T`* | *H\ :sub:`T`* | *G\ :sub:`R`* | *H\ :sub:`R`* | |
ulalume3@67 | 314 | +----------------------+-----------------------------+-----------------+-----------------+-----------------+ |
ulalume3@67 | 315 | | total | 1 | 0 | 1 | 0 | |
ulalume3@67 | 316 | +----------------------+-----------------------------+-----------------+-----------------+-----------------+ |
ulalume3@67 | 317 | | parallel | 1 | 1 | 1 | 1 | |
ulalume3@67 | 318 | +----------------------+-----------------------------+-----------------+-----------------+-----------------+ |
ulalume3@67 | 319 | | cross | 1 | -1 | 1 | -1 | |
ulalume3@67 | 320 | +----------------------+-----------------------------+-----------------+-----------------+-----------------+ |
ulalume3@67 | 321 | |
ulalume3@67 | 322 | The *apparent calibration factor* (h:sup:`\*`), *the calibration factor |
ulalume3@67 | 323 | correction* (*K*) and the *polarization cross-talk correction |
ulalume3@67 | 324 | parameters* are stored by **ELPP** module in the intermediate NetCDF |
ulalume3@67 | 325 | files using the following variables: |
ulalume3@67 | 326 | |
ulalume3@67 | 327 | - *Polarization\_Channel\_Gain\_Factor (apparent calibration factor* – |
ulalume3@67 | 328 | h\ :sup:`\*`) |
ulalume3@67 | 329 | |
ulalume3@67 | 330 | - *Polarization\_Channel\_Gain\_Factor\_Correction (calib. factor |
ulalume3@67 | 331 | corr.* – *K*) |
ulalume3@67 | 332 | |
ulalume3@67 | 333 | - *G\_T* |
ulalume3@67 | 334 | |
ulalume3@67 | 335 | - *H\_T* |
ulalume3@67 | 336 | |
ulalume3@67 | 337 | - *G\_R* |
ulalume3@67 | 338 | |
ulalume3@67 | 339 | - *H\_R* |
ulalume3@67 | 340 | |
ulalume3@67 | 341 | Finally new usecases have been defined to take into account all the |
ulalume3@67 | 342 | possible lidar configurations. The details on that are provided as a |
ulalume3@67 | 343 | separate file. |
ulalume3@67 | 344 | |
ulalume3@67 | 345 | Changes of the SCC input format |
ulalume3@67 | 346 | =============================== |
ulalume3@67 | 347 | |
ulalume3@67 | 348 | The following minor changes have been applied to raw SCC data format: |
ulalume3@67 | 349 | |
ulalume3@67 | 350 | 1. The optional variable *ID\_Range* has been *REMOVED*; |
ulalume3@67 | 351 | |
ulalume3@67 | 352 | 2. The *OPTIONAL* variable *int Signal\_Type(channels)* has been added. |
ulalume3@67 | 353 | The possible values are the same available in the SCC\_DB: |
ulalume3@67 | 354 | |
ulalume3@67 | 355 | 0 *→* elT |
ulalume3@67 | 356 | |
ulalume3@67 | 357 | 1 *→* elTnr |
ulalume3@67 | 358 | |
ulalume3@67 | 359 | 2 *→* elTfr |
ulalume3@67 | 360 | |
ulalume3@67 | 361 | 3 *→* vrRN2 |
ulalume3@67 | 362 | |
ulalume3@67 | 363 | 4 *→* vrRN2nr |
ulalume3@67 | 364 | |
ulalume3@67 | 365 | 5 *→* vrRN2fr |
ulalume3@67 | 366 | |
ulalume3@67 | 367 | 6 *→* elPR |
ulalume3@67 | 368 | |
ulalume3@67 | 369 | 7 *→* elPT |
ulalume3@67 | 370 | |
ulalume3@67 | 371 | 8 *→* pRRlow |
ulalume3@67 | 372 | |
ulalume3@67 | 373 | 9 *→* pRRhigh |
ulalume3@67 | 374 | |
ulalume3@67 | 375 | 10 *→* elPRnr |
ulalume3@67 | 376 | |
ulalume3@67 | 377 | 11 *→* elPRfr |
ulalume3@67 | 378 | |
ulalume3@67 | 379 | 12 *→* elPTnr |
ulalume3@67 | 380 | |
ulalume3@67 | 381 | 13 *→* elPTfr |
ulalume3@67 | 382 | |
ulalume3@67 | 383 | 14 *→* vrRH2O |
ulalume3@67 | 384 | |
ulalume3@67 | 385 | 15 *→* pRRhighnr |
ulalume3@67 | 386 | |
ulalume3@67 | 387 | 16 *→* pRRhighfr |
ulalume3@67 | 388 | |
ulalume3@67 | 389 | 17 *→* pRRlownr |
ulalume3@67 | 390 | |
ulalume3@67 | 391 | 18 *→* pRRlowfr |
ulalume3@67 | 392 | |
ulalume3@67 | 393 | 19 *→* vrRH2Onr |
ulalume3@67 | 394 | |
ulalume3@67 | 395 | 20 *→* vrRH2Ofr |
ulalume3@67 | 396 | |
ulalume3@67 | 397 | 21 *→* elTunr |
ulalume3@67 | 398 | |
ulalume3@67 | 399 | *22 → +45elPT* |
ulalume3@67 | 400 | |
ulalume3@67 | 401 | *23 → +45elPR* |
ulalume3@67 | 402 | |
ulalume3@67 | 403 | *24 → -45elPT* |
ulalume3@67 | 404 | |
ulalume3@67 | 405 | *25 → -45elPR* |
ulalume3@67 | 406 | |
ulalume3@67 | 407 | *26 → +45elPTnr* |
ulalume3@67 | 408 | |
ulalume3@67 | 409 | *27 → +45elPTfr* |
ulalume3@67 | 410 | |
ulalume3@67 | 411 | *28 → +45elPRnr* |
ulalume3@67 | 412 | |
ulalume3@67 | 413 | *29 → +45elPRfr* |
ulalume3@67 | 414 | |
ulalume3@67 | 415 | *30 → -45elPTnr* |
ulalume3@67 | 416 | |
ulalume3@67 | 417 | *31 → -45elPTfr* |
ulalume3@67 | 418 | |
ulalume3@67 | 419 | *32 → -45elPRnr* |
ulalume3@67 | 420 | |
ulalume3@67 | 421 | *33 → -45elPRfr* |
ulalume3@67 | 422 | |
ulalume3@67 | 423 | **WARNING:** It this variable is found in the SCC input file the |
ulalume3@67 | 424 | corresponding settings in the SCC database will be *overwritten*. Unless |
ulalume3@67 | 425 | you don't have any valid reason to overwrite the database value this |
ulalume3@67 | 426 | variable should not be used. |
ulalume3@67 | 427 | |
ulalume3@67 | 428 | 1. The variables: |
ulalume3@67 | 429 | |
ulalume3@67 | 430 | *double Pol\_Calib\_Range\_Min(channels)* |
ulalume3@67 | 431 | |
ulalume3@67 | 432 | *double Pol\_Calib\_Range\_Max(channels) * |
ulalume3@67 | 433 | |
ulalume3@67 | 434 | have been added. Both these variable are *mandatory* for any calibration |
ulalume3@67 | 435 | raw dataset. |
ulalume3@67 | 436 | |
ulalume3@67 | 437 | These variable should be included only the polarization calibration |
ulalume3@67 | 438 | measurements and should specify the altitude range (meters) in which the |
ulalume3@67 | 439 | polarization calibration should be made. For more details see section |
ulalume3@67 | 440 | 3.3; |
ulalume3@67 | 441 | |
ulalume3@67 | 442 | 1. The variable *Depolarization\_Factor* has been *removed*. |
ulalume3@67 | 443 | |
ulalume3@67 | 444 | The SCC v3.11 used this variable to get polarization calibration factor |
ulalume3@67 | 445 | for the calculation of the total signal out of cross and parallels ones. |
ulalume3@67 | 446 | As the SCC v4.0 is able to calculate the same parameter by itself, the |
ulalume3@67 | 447 | use of this variable is *NOT* possible anymore. The recommended way to |
ulalume3@67 | 448 | get a valid and quality assured depolarization calibration factor is to |
ulalume3@67 | 449 | submit to the SCC v4.0 a polarization calibration dataset and let the |
ulalume3@67 | 450 | SCC to calculate such factor. |
ulalume3@67 | 451 | |
ulalume3@67 | 452 | To make this change more smooth and to provide the users with the |
ulalume3@67 | 453 | possibility to continue to analyze their data with the SCC v4.0 even if |
ulalume3@67 | 454 | a calibration dataset has not been submitted yet, it will be possible |
ulalume3@67 | 455 | for a *LIMITED* period of time to submit the calibration constant via |
ulalume3@67 | 456 | the SCC web interface. The SCC will keep track of the used calibration |
ulalume3@67 | 457 | method (automatic or manual). |
ulalume3@67 | 458 | |
ulalume3@67 | 459 | **WARNING:** After this transition period *only* automatic calibration |
ulalume3@67 | 460 | will be allowed! |
ulalume3@67 | 461 | |
ulalume3@67 | 462 | 1. The new *optional* variable: |
ulalume3@67 | 463 | |
ulalume3@67 | 464 | *string channel\_string\_ID(channels)* |
ulalume3@67 | 465 | |
ulalume3@67 | 466 | has been introduced. |
ulalume3@67 | 467 | |
ulalume3@67 | 468 | Starting from SCC v4.0 the lidar channel can be identified not only by |
ulalume3@67 | 469 | using integers (as it happened until SCC v3.11) but also by using |
ulalume3@67 | 470 | strings. |
ulalume3@67 | 471 | |
ulalume3@67 | 472 | The procedure implemented in the SCC v4.0 to recognize the lidar channel |
ulalume3@67 | 473 | within the raw lidar data is fully backward compatible (old format files |
ulalume3@67 | 474 | are accepted as they are by SCC v4.0). |
ulalume3@67 | 475 | |
ulalume3@67 | 476 | **WARNING:** Please note that the definition of the new string variable |
ulalume3@67 | 477 | requires netCDF-4 format! The type *string* is not supported in netCDF-3 |
ulalume3@67 | 478 | format! |
ulalume3@67 | 479 | |
ulalume3@67 | 480 | Real Example |
ulalume3@67 | 481 | ============ |
ulalume3@67 | 482 | |
ulalume3@67 | 483 | This section describes all the practical steps the users need to follow |
ulalume3@67 | 484 | to switch from SCC v3.11 to new SCC v4.0. |
ulalume3@67 | 485 | |
ulalume3@67 | 486 | **IMPORTANT:** |
ulalume3@67 | 487 | |
ulalume3@67 | 488 | If your lidar system is not equipped with any polarization channels *NO* |
ulalume3@67 | 489 | changes are required. In this case, the SCC v4.0 should work using the |
ulalume3@67 | 490 | same input files and the same database configurations you have used with |
ulalume3@67 | 491 | the SCC v3.11. Anyway as in the SCC v4.0 several bugs have been fixed, |
ulalume3@67 | 492 | it is recommended to re-run all the measurement IDs you have submitted. |
ulalume3@67 | 493 | For doing that you just need to reprocess all your data without the need |
ulalume3@67 | 494 | to submit raw data files already uploaded on the server. |
ulalume3@67 | 495 | |
ulalume3@67 | 496 | The practical example reported below describes the modifications |
ulalume3@67 | 497 | required to use the SCC v4.0 for lidar systems equipped with |
ulalume3@67 | 498 | polarization channels. |
ulalume3@67 | 499 | |
ulalume3@67 | 500 | Modification of polarization channel parameters |
ulalume3@67 | 501 | ----------------------------------------------- |
ulalume3@67 | 502 | |
ulalume3@67 | 503 | In what it follows it is assumed you already have registered one or more |
ulalume3@67 | 504 | lidar configurations in the SCC database and that such configurations |
ulalume3@67 | 505 | have been already used to produce optical products (aerosol extinction |
ulalume3@67 | 506 | and/or backscatter coefficients) by means of the SCC v3.11. |
ulalume3@67 | 507 | |
ulalume3@67 | 508 | Let's assume your 3+2 system is registered in the SCC database and the |
ulalume3@67 | 509 | settings used by the SCC v3.11 are the ones summarized in table 3.1. |
ulalume3@67 | 510 | |
ulalume3@67 | 511 | **Table 3.1:** Example of configuration in SCC v3.11 |
ulalume3@67 | 512 | |
ulalume3@67 | 513 | +----------------+--------------+----------------+-------------+-----------+ |
ulalume3@67 | 514 | | Channel Name | Channel ID | Channel Type | nighttime | daytime | |
ulalume3@67 | 515 | +----------------+--------------+----------------+-------------+-----------+ |
ulalume3@67 | 516 | | 355 | 1 | elT | | | |
ulalume3@67 | 517 | +----------------+--------------+----------------+-------------+-----------+ |
ulalume3@67 | 518 | | 387 | 2 | vrRN2 | | | |
ulalume3@67 | 519 | +----------------+--------------+----------------+-------------+-----------+ |
ulalume3@67 | 520 | | 532 cross | 3 | elCP | | | |
ulalume3@67 | 521 | +----------------+--------------+----------------+-------------+-----------+ |
ulalume3@67 | 522 | | 532 parallel | 4 | elPP | | | |
ulalume3@67 | 523 | +----------------+--------------+----------------+-------------+-----------+ |
ulalume3@67 | 524 | | 607 | 5 | vrRN2 | | | |
ulalume3@67 | 525 | +----------------+--------------+----------------+-------------+-----------+ |
ulalume3@67 | 526 | | 1064 | 6 | elT | | | |
ulalume3@67 | 527 | +----------------+--------------+----------------+-------------+-----------+ |
ulalume3@67 | 528 | |
ulalume3@67 | 529 | We assume there are 2 system configurations called “nighttime” and |
ulalume3@67 | 530 | “daytime”. The nighttime configuration contains all the available lidar |
ulalume3@67 | 531 | channels (in order to calculate, for example, the aerosol extinction at |
ulalume3@67 | 532 | 355 and 532nm and the aerosol backscatter at 355, 532 and 1064nm) while |
ulalume3@67 | 533 | in daytime conditions only elastic channels are used (only elastic |
ulalume3@67 | 534 | backscatter coefficients are generated). |
ulalume3@67 | 535 | |
ulalume3@67 | 536 | To make these settings working with SCC v4.0 it is needed to modify |
ulalume3@67 | 537 | *ONLY* the products properties involving the polarization channels (532 |
ulalume3@67 | 538 | cross and parallel). All the products not involving the polarization |
ulalume3@67 | 539 | channels *DO NOT* need any modification and should work in the SCC v4.0 |
ulalume3@67 | 540 | exactly as they did in SCC v3.11. In the example above the aerosol |
ulalume3@67 | 541 | extinction and backscatter coefficient at 355nm, the extinction at 532nm |
ulalume3@67 | 542 | as well as the backscatter coefficient at 1064nm do not required any |
ulalume3@67 | 543 | modification. Let's focus on the modifications needed for the |
ulalume3@67 | 544 | calculation of backscatter at 532nm. |
ulalume3@67 | 545 | |
ulalume3@67 | 546 | |image0| How to select signal types |
ulalume3@67 | 547 | |
ulalume3@67 | 548 | The first modification concerns the settings of the channel type for the |
ulalume3@67 | 549 | 532 cross and 532 parallel polarization channels. Starting from SCC v4.0 |
ulalume3@67 | 550 | polarization channels are identified as transmitted and reflected |
ulalume3@67 | 551 | polarization channels and not on the base of their polarization state. |
ulalume3@67 | 552 | So suppose if we suppose the cross polarized channel is transmitted by a |
ulalume3@67 | 553 | polarizer beam splitter cube and the parallel is reflected the value |
ulalume3@67 | 554 | reported in table 3.1 should be modified as they appear in table 3.2. So |
ulalume3@67 | 555 | using the SCC web interface, the signal type of the 532 cross channel |
ulalume3@67 | 556 | should be changed from elCP to elPT and and in the same way the 532 |
ulalume3@67 | 557 | parallel channel should be changed from elPP to elPR (see figure 3.1). |
ulalume3@67 | 558 | |
ulalume3@67 | 559 | **Table 3.2:** The same of table 3.1 but with new channel types |
ulalume3@67 | 560 | introduced in SCC v4.0 |
ulalume3@67 | 561 | |
ulalume3@67 | 562 | +----------------+--------------+----------------+-------------+-----------+ |
ulalume3@67 | 563 | | Channel Name | Channel ID | Channel Type | nighttime | daytime | |
ulalume3@67 | 564 | +----------------+--------------+----------------+-------------+-----------+ |
ulalume3@67 | 565 | | 355 | 1 | elT | | | |
ulalume3@67 | 566 | +----------------+--------------+----------------+-------------+-----------+ |
ulalume3@67 | 567 | | 387 | 2 | vrRN2 | | | |
ulalume3@67 | 568 | +----------------+--------------+----------------+-------------+-----------+ |
ulalume3@67 | 569 | | 532 cross | 3 | **elPT** | | | |
ulalume3@67 | 570 | +----------------+--------------+----------------+-------------+-----------+ |
ulalume3@67 | 571 | | 532 parallel | 4 | **elPR** | | | |
ulalume3@67 | 572 | +----------------+--------------+----------------+-------------+-----------+ |
ulalume3@67 | 573 | | 607 | 5 | vrRN2 | | | |
ulalume3@67 | 574 | +----------------+--------------+----------------+-------------+-----------+ |
ulalume3@67 | 575 | | 1064 | 6 | elT | | | |
ulalume3@67 | 576 | +----------------+--------------+----------------+-------------+-----------+ |
ulalume3@67 | 577 | |
ulalume3@67 | 578 | The other change about the polarization channels required to run the SCC |
ulalume3@67 | 579 | v4.0 is the definition of the polarization crosstalk parameters for all |
ulalume3@67 | 580 | the polarization channels available. Such parameters can be defined for |
ulalume3@67 | 581 | each polarization channel using the SCC web interface (see figure 3.2). |
ulalume3@67 | 582 | In particular among the channel parameters there is a new tab called |
ulalume3@67 | 583 | *Polarization crosstalk parameters* where it is possible to insert the |
ulalume3@67 | 584 | values from for the parameters *G* and *H* and the corresponding |
ulalume3@67 | 585 | statistical and systematic errors if available. In case you have |
ulalume3@67 | 586 | measured *G* and *H* for your polarization channels please insert the |
ulalume3@67 | 587 | corresponding values there. Otherwise you can insert the ideal values as |
ulalume3@67 | 588 | reported in table 1.1. |
ulalume3@67 | 589 | |
ulalume3@67 | 590 | |image1| *Polarization crosstalk parameters* tab in channel properties |
ulalume3@67 | 591 | (SCC v4.0). |
ulalume3@67 | 592 | |
ulalume3@67 | 593 | Definition of new calibration configuration and product |
ulalume3@67 | 594 | ------------------------------------------------------- |
ulalume3@67 | 595 | |
ulalume3@67 | 596 | In this section we will see how to set the polarization calibration |
ulalume3@67 | 597 | parameters: the calibration constant (called h\ :sup:`\*` in section |
ulalume3@67 | 598 | 1.3) and the correction to calibration constant (called K in section |
ulalume3@67 | 599 | 1.3). |
ulalume3@67 | 600 | |
ulalume3@67 | 601 | In order to provide such parameters you need to define a new system |
ulalume3@67 | 602 | configuration to be used *only* for calibration purposes. Such new |
ulalume3@67 | 603 | configuration should include the polarization channels in the |
ulalume3@67 | 604 | measurement configuration used for the calibration. Let's suppose we |
ulalume3@67 | 605 | want to use the D90 calibration method. |
ulalume3@67 | 606 | |
ulalume3@67 | 607 | In this case we need to define a new configuration (called for example |
ulalume3@67 | 608 | “depol\_calibration”) as reported in the table 3.3. As you can see the |
ulalume3@67 | 609 | configuration “depol\_calibration” includes 4 “new” channels. Actually |
ulalume3@67 | 610 | the channels “532 cross +45 degrees” (channel ID=10) and “532 cross -45 |
ulalume3@67 | 611 | degrees” (channel ID=12) refer to the same physical channel “532 cross” |
ulalume3@67 | 612 | reported with channel ID=3 in table 3.2. Anyway we need to define two |
ulalume3@67 | 613 | new channel IDs to identify the “532 cross” channel in the two |
ulalume3@67 | 614 | polarization rotated configurations (+45 and -45 degrees) needed to |
ulalume3@67 | 615 | apply the D90 calibration method. The same is true for the “532 |
ulalume3@67 | 616 | parallel” channel. The polarization rotated channels should be labeled |
ulalume3@67 | 617 | with the corresponding signal type as reported in table 3.3 (see figure |
ulalume3@67 | 618 | 3.1). |
ulalume3@67 | 619 | |
ulalume3@67 | 620 | **Table 3.3:** Polarization calibration configurations assuming D90 |
ulalume3@67 | 621 | calibration method |
ulalume3@67 | 622 | |
ulalume3@67 | 623 | +----------------------------+--------------+----------------+----------------------+ |
ulalume3@67 | 624 | | Channel Name | Channel ID | Channel Type | depol\_calibration | |
ulalume3@67 | 625 | +----------------------------+--------------+----------------+----------------------+ |
ulalume3@67 | 626 | | 532 cross +45 degrees | 10 | +45elPT | | |
ulalume3@67 | 627 | +----------------------------+--------------+----------------+----------------------+ |
ulalume3@67 | 628 | | 532 parallel +45 degrees | 11 | +45elPR | | |
ulalume3@67 | 629 | +----------------------------+--------------+----------------+----------------------+ |
ulalume3@67 | 630 | | 532 cross -45 degrees | 12 | -45elPT | | |
ulalume3@67 | 631 | +----------------------------+--------------+----------------+----------------------+ |
ulalume3@67 | 632 | | 532 parallel -45 degrees | 13 | -45elPR | | |
ulalume3@67 | 633 | +----------------------------+--------------+----------------+----------------------+ |
ulalume3@67 | 634 | |
ulalume3@67 | 635 | Finally we should add to the configuration “depol\_calibration” a |
ulalume3@67 | 636 | product “\ *Linear polarization calibration”* to be used for the |
ulalume3@67 | 637 | calibration. According to the example given above and to the usecase |
ulalume3@67 | 638 | document attached we should use an usecase=4 for this example. |
ulalume3@67 | 639 | |
ulalume3@67 | 640 | Other “\ *Linear polarization calibration”* options to be specified are |
ulalume3@67 | 641 | reported in figure 3.3. The most important factor you should insert here |
ulalume3@67 | 642 | is the *Pol calibration correction factor* (K). The ideal value for this |
ulalume3@67 | 643 | parameter is 1. Anyway if you have measured the parameter K please fill |
ulalume3@67 | 644 | in the measured value and the corresponding measurement errors. |
ulalume3@67 | 645 | |
ulalume3@67 | 646 | |image2| Options for *Linear polarization calibration product*. |
ulalume3@67 | 647 | |
ulalume3@67 | 648 | As you can see it is possible to fill in only the K correction factor |
ulalume3@67 | 649 | and not the calibration constant h\ :sup:`\*`. |
ulalume3@67 | 650 | |
ulalume3@67 | 651 | Actually for a *LIMITED* period of time it will be possible to fill in |
ulalume3@67 | 652 | also the constant h\ :sup:`\*` using a temporary tab called |
ulalume3@67 | 653 | *Polarization calibration constant*. This has been done to provide the |
ulalume3@67 | 654 | users with the possibility to continue to use the SCC even if an |
ulalume3@67 | 655 | automatic calibration made by the SCC was not submitted yet. Anyway |
ulalume3@67 | 656 | after a transition period it will be *not* possible to provide |
ulalume3@67 | 657 | calibration constant using this procedure and the parameter h\ :sup:`\*` |
ulalume3@67 | 658 | can be calculated *ONLY* by the SCC as result of the submission of a |
ulalume3@67 | 659 | proper calibration raw input dataset. The format of this input file is |
ulalume3@67 | 660 | the same as the standard SCC input file. The only difference is that is |
ulalume3@67 | 661 | should contain calibration measurements instead of standard |
ulalume3@67 | 662 | measurements. Following our example, such file should contain the |
ulalume3@67 | 663 | measurement performed at +45 and -45 degrees at 532nm. Also the channel |
ulalume3@67 | 664 | IDs in the file should reflect the ones reported in table 3.3. |
ulalume3@67 | 665 | |
ulalume3@67 | 666 | Moreover this raw input file has to contain the variables: |
ulalume3@67 | 667 | |
ulalume3@67 | 668 | *double Pol\_Calib\_Range\_Min(channels)* |
ulalume3@67 | 669 | |
ulalume3@67 | 670 | *double Pol\_Calib\_Range\_Max(channels) * |
ulalume3@67 | 671 | |
ulalume3@67 | 672 | where to specify the altitude ranges in meters in which the polarization |
ulalume3@67 | 673 | calibration should be done. |
ulalume3@67 | 674 | |
ulalume3@67 | 675 | According to the table 3.3 this file should be something similar to: |
ulalume3@67 | 676 | |
ulalume3@67 | 677 | dimensions: |
ulalume3@67 | 678 | |
ulalume3@67 | 679 | channels = 4 ; |
ulalume3@67 | 680 | |
ulalume3@67 | 681 | nb\_of\_time\_scales = 1 ; |
ulalume3@67 | 682 | |
ulalume3@67 | 683 | points = 16380 ; |
ulalume3@67 | 684 | |
ulalume3@67 | 685 | scan\_angles = 1 ; |
ulalume3@67 | 686 | |
ulalume3@67 | 687 | time = UNLIMITED ; // (3 currently) |
ulalume3@67 | 688 | |
ulalume3@67 | 689 | variables: |
ulalume3@67 | 690 | |
ulalume3@67 | 691 | int channel\_ID(channels) ; |
ulalume3@67 | 692 | |
ulalume3@67 | 693 | double Background\_Low(channels) ; |
ulalume3@67 | 694 | |
ulalume3@67 | 695 | double Background\_High(channels) ; |
ulalume3@67 | 696 | |
ulalume3@67 | 697 | int id\_timescale(channels) ; |
ulalume3@67 | 698 | |
ulalume3@67 | 699 | double Laser\_Pointing\_Angle(scan\_angles) ; |
ulalume3@67 | 700 | |
ulalume3@67 | 701 | int Molecular\_Calc ; |
ulalume3@67 | 702 | |
ulalume3@67 | 703 | int Laser\_Pointing\_Angle\_of\_Profiles(time, nb\_of\_time\_scales) ; |
ulalume3@67 | 704 | |
ulalume3@67 | 705 | int Raw\_Data\_Start\_Time(time, nb\_of\_time\_scales) ; |
ulalume3@67 | 706 | |
ulalume3@67 | 707 | int Raw\_Data\_Stop\_Time(time, nb\_of\_time\_scales) ; |
ulalume3@67 | 708 | |
ulalume3@67 | 709 | int Laser\_Shots(time, channels) ; |
ulalume3@67 | 710 | |
ulalume3@67 | 711 | double Raw\_Lidar\_Data(time, channels, points) ; |
ulalume3@67 | 712 | |
ulalume3@67 | 713 | double Pressure\_at\_Lidar\_Station ; |
ulalume3@67 | 714 | |
ulalume3@67 | 715 | double Temperature\_at\_Lidar\_Station ; |
ulalume3@67 | 716 | |
ulalume3@67 | 717 | double Pol\_Calib\_Range\_Min(channels) ; |
ulalume3@67 | 718 | |
ulalume3@67 | 719 | double Pol\_Calib\_Range\_Max(channels) ; |
ulalume3@67 | 720 | |
ulalume3@67 | 721 | // global attributes: |
ulalume3@67 | 722 | |
ulalume3@67 | 723 | :System = "mysystem" ; |
ulalume3@67 | 724 | |
ulalume3@67 | 725 | :Longitude\_degrees\_east = 15.723771 ; |
ulalume3@67 | 726 | |
ulalume3@67 | 727 | :RawData\_Start\_Time\_UT = "220000" ; |
ulalume3@67 | 728 | |
ulalume3@67 | 729 | :RawData\_Start\_Date = "20130620" ; |
ulalume3@67 | 730 | |
ulalume3@67 | 731 | :Measurement\_ID = "20130620po00" ; |
ulalume3@67 | 732 | |
ulalume3@67 | 733 | :Altitude\_meter\_asl = 760. ; |
ulalume3@67 | 734 | |
ulalume3@67 | 735 | :RawData\_Stop\_Time\_UT = "230333" ; |
ulalume3@67 | 736 | |
ulalume3@67 | 737 | :Latitude\_degrees\_north = 40.601039 ; |
ulalume3@67 | 738 | |
ulalume3@67 | 739 | data: |
ulalume3@67 | 740 | |
ulalume3@67 | 741 | channel\_ID = 10, 11, 12, 13 ; |
ulalume3@67 | 742 | |
ulalume3@67 | 743 | Background\_Low = 30000, 30000, 30000, 30000 ; |
ulalume3@67 | 744 | |
ulalume3@67 | 745 | Background\_High = 50000, 50000, 50000, 50000 ; |
ulalume3@67 | 746 | |
ulalume3@67 | 747 | id\_timescale = 0, 0, 0, 0 ; |
ulalume3@67 | 748 | |
ulalume3@67 | 749 | Laser\_Pointing\_Angle = 0 ; |
ulalume3@67 | 750 | |
ulalume3@67 | 751 | Molecular\_Calc = 0 ; |
ulalume3@67 | 752 | |
ulalume3@67 | 753 | Laser\_Pointing\_Angle\_of\_Profiles = |
ulalume3@67 | 754 | |
ulalume3@67 | 755 | 0, |
ulalume3@67 | 756 | |
ulalume3@67 | 757 | 0, |
ulalume3@67 | 758 | |
ulalume3@67 | 759 | 0 ; |
ulalume3@67 | 760 | |
ulalume3@67 | 761 | Raw\_Data\_Start\_Time = |
ulalume3@67 | 762 | |
ulalume3@67 | 763 | 0, |
ulalume3@67 | 764 | |
ulalume3@67 | 765 | 300, |
ulalume3@67 | 766 | |
ulalume3@67 | 767 | 600 ; |
ulalume3@67 | 768 | |
ulalume3@67 | 769 | Raw\_Data\_Stop\_Time = |
ulalume3@67 | 770 | |
ulalume3@67 | 771 | 210, |
ulalume3@67 | 772 | |
ulalume3@67 | 773 | 510, |
ulalume3@67 | 774 | |
ulalume3@67 | 775 | 810 ; |
ulalume3@67 | 776 | |
ulalume3@67 | 777 | Laser\_Shots = |
ulalume3@67 | 778 | |
ulalume3@67 | 779 | 1200, 1200, 1200, 1200, |
ulalume3@67 | 780 | |
ulalume3@67 | 781 | 1200, 1200, 1200, 1200, |
ulalume3@67 | 782 | |
ulalume3@67 | 783 | 1200, 1200, 1200, 1200 ; |
ulalume3@67 | 784 | |
ulalume3@67 | 785 | Pressure\_at\_Lidar\_Station = 1010 ; |
ulalume3@67 | 786 | |
ulalume3@67 | 787 | Temperature\_at\_Lidar\_Station = 14 ; |
ulalume3@67 | 788 | |
ulalume3@67 | 789 | Pol\_Calib\_Range\_Min = 1000, 1000, 1000, 1000 ; |
ulalume3@67 | 790 | |
ulalume3@67 | 791 | Pol\_Calib\_Range\_Min = 2000, 2000, 2000, 2000 ; |
ulalume3@67 | 792 | |
ulalume3@67 | 793 | Raw\_Lidar\_Data = …...; |
ulalume3@67 | 794 | |
ulalume3@67 | 795 | The file above assume the following calibration measurements have been |
ulalume3@67 | 796 | done: |
ulalume3@67 | 797 | |
ulalume3@67 | 798 | 1. First +45 degrees acquisition followed by a corresponding -45 degrees |
ulalume3@67 | 799 | acquisition |
ulalume3@67 | 800 | |
ulalume3@67 | 801 | a. Measurement at +45 degrees |
ulalume3@67 | 802 | |
ulalume3@67 | 803 | Start Time: 20130620 22:00:00 |
ulalume3@67 | 804 | |
ulalume3@67 | 805 | Stop Time: 20130620 22:01:00 |
ulalume3@67 | 806 | |
ulalume3@67 | 807 | Shots: 1200 |
ulalume3@67 | 808 | |
ulalume3@67 | 809 | a. Measurement at -45 degrees |
ulalume3@67 | 810 | |
ulalume3@67 | 811 | Start Time: 20130620 22:02:30 |
ulalume3@67 | 812 | |
ulalume3@67 | 813 | Stop Time: 20130620 22:03:30 |
ulalume3@67 | 814 | |
ulalume3@67 | 815 | Shots: 1200 |
ulalume3@67 | 816 | |
ulalume3@67 | 817 | 1. Second +45 degrees acquisition followed by a corresponding -45 |
ulalume3@67 | 818 | degrees acquisition |
ulalume3@67 | 819 | |
ulalume3@67 | 820 | a. Measurement at +45 degrees |
ulalume3@67 | 821 | |
ulalume3@67 | 822 | Start Time: 20130620 22:05:00 |
ulalume3@67 | 823 | |
ulalume3@67 | 824 | Stop Time: 20130620 22:06:00 |
ulalume3@67 | 825 | |
ulalume3@67 | 826 | Shots: 1200 |
ulalume3@67 | 827 | |
ulalume3@67 | 828 | a. Measurement at -45 degrees |
ulalume3@67 | 829 | |
ulalume3@67 | 830 | Start Time: 20130620 22:07:30 |
ulalume3@67 | 831 | |
ulalume3@67 | 832 | Stop Time: 20130620 22:08:30 |
ulalume3@67 | 833 | |
ulalume3@67 | 834 | Shots: 1200 |
ulalume3@67 | 835 | |
ulalume3@67 | 836 | 1. Third +45 degrees acquisition followed by a corresponding -45 degrees |
ulalume3@67 | 837 | acquisition |
ulalume3@67 | 838 | |
ulalume3@67 | 839 | a. Measurement at +45 degrees |
ulalume3@67 | 840 | |
ulalume3@67 | 841 | Start Time: 20130620 22:10:00 |
ulalume3@67 | 842 | |
ulalume3@67 | 843 | Stop Time: 20130620 22:11:00 |
ulalume3@67 | 844 | |
ulalume3@67 | 845 | Shots: 1200 |
ulalume3@67 | 846 | |
ulalume3@67 | 847 | a. Measurement at -45 degrees |
ulalume3@67 | 848 | |
ulalume3@67 | 849 | Start Time: 20130620 22:12:30 |
ulalume3@67 | 850 | |
ulalume3@67 | 851 | Stop Time: 20130620 22:13:30 |
ulalume3@67 | 852 | |
ulalume3@67 | 853 | Shots: 1200 |
ulalume3@67 | 854 | |
ulalume3@67 | 855 | As you can see there are 3 cycles of consecutive measurements at +45 and |
ulalume3@67 | 856 | -45 degrees. That's way the dimension time is set to 3. |
ulalume3@67 | 857 | |
ulalume3@67 | 858 | The first +/-45 degrees measurement starts at “20130620 22:00:00” (start |
ulalume3@67 | 859 | time of the first +45 measurement) and stops at “20130620 22:03:30” |
ulalume3@67 | 860 | (stop time of the fist -45 measurement). As a consequence, according to |
ulalume3@67 | 861 | the values of the global attributes RawData\_Start\_Date and |
ulalume3@67 | 862 | RawData\_Start\_Time\_UT we have to set: |
ulalume3@67 | 863 | |
ulalume3@67 | 864 | Raw\_Data\_Start\_Time[0]=0 (start of the first +45 measurement in |
ulalume3@67 | 865 | seconds since RawData\_Start\_Time\_UT) |
ulalume3@67 | 866 | |
ulalume3@67 | 867 | Raw\_Data\_Stop\_Time[0]=210 (stop of the first -45 measurement in |
ulalume3@67 | 868 | seconds since RawData\_Start\_Time\_UT) |
ulalume3@67 | 869 | |
ulalume3@67 | 870 | Following a similar procedure for the other 2 cycles we have: |
ulalume3@67 | 871 | |
ulalume3@67 | 872 | Raw\_Data\_Start\_Time[1]=300 (start of the second +45 measurement in |
ulalume3@67 | 873 | seconds since RawData\_Start\_Time\_UT) |
ulalume3@67 | 874 | |
ulalume3@67 | 875 | Raw\_Data\_Stop\_Time[1]=510 (stop of the second -45 measurement in |
ulalume3@67 | 876 | seconds since RawData\_Start\_Time\_UT) |
ulalume3@67 | 877 | |
ulalume3@67 | 878 | Raw\_Data\_Start\_Time[2]=600 (start of the third +45 measurement in |
ulalume3@67 | 879 | seconds since RawData\_Start\_Time\_UT) |
ulalume3@67 | 880 | |
ulalume3@67 | 881 | Raw\_Data\_Stop\_Time[2]=810 (stop of the third -45 measurement in |
ulalume3@67 | 882 | seconds since RawData\_Start\_Time\_UT) |
ulalume3@67 | 883 | |
ulalume3@67 | 884 | Moreover, according to the order of the channels in the channel\_ID |
ulalume3@67 | 885 | variable, the Raw\_Lidar\_Data array should be filled as it follows: |
ulalume3@67 | 886 | |
ulalume3@67 | 887 | Raw\_Lidar\_Data[0][0][points] → 1\ :sup:`st` measured transmitted |
ulalume3@67 | 888 | signal at +45 degrees |
ulalume3@67 | 889 | |
ulalume3@67 | 890 | Raw\_Lidar\_Data[0][1][points] → 1\ :sup:`st` measured reflected signal |
ulalume3@67 | 891 | at +45 degrees |
ulalume3@67 | 892 | |
ulalume3@67 | 893 | Raw\_Lidar\_Data[0][2][points] → 1\ :sup:`st` measured transmitted |
ulalume3@67 | 894 | signal at -45 degrees |
ulalume3@67 | 895 | |
ulalume3@67 | 896 | Raw\_Lidar\_Data[0][3][points] → 1\ :sup:`st` measured reflected signal |
ulalume3@67 | 897 | at -45 degrees |
ulalume3@67 | 898 | |
ulalume3@67 | 899 | Raw\_Lidar\_Data[1][0][points] → 2\ :sup:`nd` measured transmitted |
ulalume3@67 | 900 | signal at +45 degrees |
ulalume3@67 | 901 | |
ulalume3@67 | 902 | Raw\_Lidar\_Data[1][1][points] → 2\ :sup:`nd` measured reflected signal |
ulalume3@67 | 903 | at +45 degrees |
ulalume3@67 | 904 | |
ulalume3@67 | 905 | Raw\_Lidar\_Data[1][2][points] → 2\ :sup:`nd` measured transmitted |
ulalume3@67 | 906 | signal at -45 degrees |
ulalume3@67 | 907 | |
ulalume3@67 | 908 | Raw\_Lidar\_Data[1][3][points] → 2\ :sup:`nd` measured reflected signal |
ulalume3@67 | 909 | at -45 degrees |
ulalume3@67 | 910 | |
ulalume3@67 | 911 | Raw\_Lidar\_Data[2][0][points] → 3\ :sup:`rd` measured transmitted |
ulalume3@67 | 912 | signal at +45 degrees |
ulalume3@67 | 913 | |
ulalume3@67 | 914 | Raw\_Lidar\_Data[2][1][points] → 3\ :sup:`rd` measured reflected signal |
ulalume3@67 | 915 | at +45 degrees |
ulalume3@67 | 916 | |
ulalume3@67 | 917 | Raw\_Lidar\_Data[2][2][points] → 3\ :sup:`rd` measured transmitted |
ulalume3@67 | 918 | signal at -45 degrees |
ulalume3@67 | 919 | |
ulalume3@67 | 920 | Raw\_Lidar\_Data[2][3][points] → 3\ :sup:`rd` measured reflected signal |
ulalume3@67 | 921 | at -45 degrees |
ulalume3@67 | 922 | |
ulalume3@67 | 923 | Once this file has been created it needs to be submitted to the SCC and |
ulalume3@67 | 924 | linked to the configuration “depol\_calibration”. The result of the SCC |
ulalume3@67 | 925 | analysis on this file will be the calculation of the calibration |
ulalume3@67 | 926 | constant h\ :sup:`\*` that will be logged into the SCC database and can |
ulalume3@67 | 927 | be used to calibrate Raman/Elastic backscat ter products (see section |
ulalume3@67 | 928 | 3.3). |
ulalume3@67 | 929 | |
ulalume3@67 | 930 | **Definition of “Raman/Elastic backscatter and linear depolarization ratio”** |
ulalume3@67 | 931 | ----------------------------------------------------------------------------- |
ulalume3@67 | 932 | |
ulalume3@67 | 933 | In order to calculate the *PLDR* we need to modify the polarization |
ulalume3@67 | 934 | related products linked to the “standard” measurement configurations |
ulalume3@67 | 935 | (the configuration called “nighttime” and/or “daytime” in table 3.2). |
ulalume3@67 | 936 | |
ulalume3@67 | 937 | Let's suppose we have defined the following products (defined already in |
ulalume3@67 | 938 | SCC v3.11): |
ulalume3@67 | 939 | |
ulalume3@67 | 940 | **Table 3.4:** Example of products configuration in SCC v3.11 |
ulalume3@67 | 941 | |
ulalume3@67 | 942 | +-----------------------+--------------+-----------------------+-------------+-----------+ |
ulalume3@67 | 943 | | Product Name | Product ID | Product Type | nighttime | daytime | |
ulalume3@67 | 944 | +-----------------------+--------------+-----------------------+-------------+-----------+ |
ulalume3@67 | 945 | | Raman backscatter | 1 | Raman backscatter | | | |
ulalume3@67 | 946 | | | | | | | |
ulalume3@67 | 947 | | 355nm | | | | | |
ulalume3@67 | 948 | +-----------------------+--------------+-----------------------+-------------+-----------+ |
ulalume3@67 | 949 | | Extinction | 2 | Extinction | | | |
ulalume3@67 | 950 | | | | | | | |
ulalume3@67 | 951 | | 387nm | | | | | |
ulalume3@67 | 952 | +-----------------------+--------------+-----------------------+-------------+-----------+ |
ulalume3@67 | 953 | | Raman backscatter | 3 | Raman backscatter | | | |
ulalume3@67 | 954 | | | | | | | |
ulalume3@67 | 955 | | 532nm | | | | | |
ulalume3@67 | 956 | +-----------------------+--------------+-----------------------+-------------+-----------+ |
ulalume3@67 | 957 | | Extinction | 4 | Extinction | | | |
ulalume3@67 | 958 | | | | | | | |
ulalume3@67 | 959 | | 532nm | | | | | |
ulalume3@67 | 960 | +-----------------------+--------------+-----------------------+-------------+-----------+ |
ulalume3@67 | 961 | | Elastic backscatter | 5 | Elastic backscatter | | | |
ulalume3@67 | 962 | | | | | | | |
ulalume3@67 | 963 | | 355nm | | | | | |
ulalume3@67 | 964 | +-----------------------+--------------+-----------------------+-------------+-----------+ |
ulalume3@67 | 965 | | Elastic backscatter | 6 | Elastic backscatter | | | |
ulalume3@67 | 966 | | | | | | | |
ulalume3@67 | 967 | | 532nm | | | | | |
ulalume3@67 | 968 | +-----------------------+--------------+-----------------------+-------------+-----------+ |
ulalume3@67 | 969 | | Elastic backscatter | 7 | Elastic backscatter | | | |
ulalume3@67 | 970 | | | | | | | |
ulalume3@67 | 971 | | 1064nm | | | | | |
ulalume3@67 | 972 | +-----------------------+--------------+-----------------------+-------------+-----------+ |
ulalume3@67 | 973 | |
ulalume3@67 | 974 | Product ID=1, 2, 4, 5, 7 do not need any modification as they do not |
ulalume3@67 | 975 | involve polarization channels. The only product that need to be modified |
ulalume3@67 | 976 | are the Product ID=3 and 6. To produce b532 files containing also *PLDR* |
ulalume3@67 | 977 | we need to modify the “nighttime” and “daytime” configurations to |
ulalume3@67 | 978 | include a product of type “Raman bakscatter and linear depolarization |
ulalume3@67 | 979 | ratio” or “Elastic bakscatter and linear depolarization ratio” |
ulalume3@67 | 980 | respectively. So the configuration reported in table 3.4 should be |
ulalume3@67 | 981 | changed to match what is included in table 3.5. |
ulalume3@67 | 982 | |
ulalume3@67 | 983 | **Table 3.5:** The same of table 3.4 but with new product types |
ulalume3@67 | 984 | introduced in SCC v4.0 |
ulalume3@67 | 985 | |
ulalume3@67 | 986 | +-----------------------+--------------+-----------------------------------------------------------+-------------+-----------+ |
ulalume3@67 | 987 | | Product Name | Product ID | Product Type | nighttime | daytime | |
ulalume3@67 | 988 | +-----------------------+--------------+-----------------------------------------------------------+-------------+-----------+ |
ulalume3@67 | 989 | | Raman backscatter | 1 | Raman backscatter | | | |
ulalume3@67 | 990 | | | | | | | |
ulalume3@67 | 991 | | 355nm | | | | | |
ulalume3@67 | 992 | +-----------------------+--------------+-----------------------------------------------------------+-------------+-----------+ |
ulalume3@67 | 993 | | Extinction | 2 | Extinction | | | |
ulalume3@67 | 994 | | | | | | | |
ulalume3@67 | 995 | | 387nm | | | | | |
ulalume3@67 | 996 | +-----------------------+--------------+-----------------------------------------------------------+-------------+-----------+ |
ulalume3@67 | 997 | | Raman backscatter | 10 | **Raman backscatter and linear depolarization ratio** | | | |
ulalume3@67 | 998 | | | | | | | |
ulalume3@67 | 999 | | 532nm | | | | | |
ulalume3@67 | 1000 | +-----------------------+--------------+-----------------------------------------------------------+-------------+-----------+ |
ulalume3@67 | 1001 | | Extinction | 4 | Extinction | | | |
ulalume3@67 | 1002 | | | | | | | |
ulalume3@67 | 1003 | | 532nm | | | | | |
ulalume3@67 | 1004 | +-----------------------+--------------+-----------------------------------------------------------+-------------+-----------+ |
ulalume3@67 | 1005 | | Elastic backscatter | 5 | Elastic backscatter | | | |
ulalume3@67 | 1006 | | | | | | | |
ulalume3@67 | 1007 | | 355nm | | | | | |
ulalume3@67 | 1008 | +-----------------------+--------------+-----------------------------------------------------------+-------------+-----------+ |
ulalume3@67 | 1009 | | Elastic backscatter | 11 | **Elastic backscatter and linear depolarization ratio** | | | |
ulalume3@67 | 1010 | | | | | | | |
ulalume3@67 | 1011 | | 532nm | | | | | |
ulalume3@67 | 1012 | +-----------------------+--------------+-----------------------------------------------------------+-------------+-----------+ |
ulalume3@67 | 1013 | | Elastic backscatter | 7 | Elastic backscatter | | | |
ulalume3@67 | 1014 | | | | | | | |
ulalume3@67 | 1015 | | 1064nm | | | | | |
ulalume3@67 | 1016 | +-----------------------+--------------+-----------------------------------------------------------+-------------+-----------+ |
ulalume3@67 | 1017 | |
ulalume3@67 | 1018 | As you can see in table 3.5, the old product IDs=3 and 6 (present in |
ulalume3@67 | 1019 | table 3.4) have been replaced with the new product ID=10 and 11 to |
ulalume3@67 | 1020 | guarantee the calculation of *PLDR*. |
ulalume3@67 | 1021 | |
ulalume3@67 | 1022 | It is important to set among the product options of the product ID=10 |
ulalume3@67 | 1023 | and 11 which calibration product we want to use for calibration (see |
ulalume3@67 | 1024 | section 3.2). This can be done using the SCC web interface setting the |
ulalume3@67 | 1025 | appropriate setting in the tab *Polarization calibration products* (see |
ulalume3@67 | 1026 | figure 3.4). According to the current example you should set here the |
ulalume3@67 | 1027 | calibration product defined in section 3.2. |
ulalume3@67 | 1028 | |
ulalume3@67 | 1029 | |image3| How to link a product to calibrate with a calibration product. |
ulalume3@67 | 1030 | |
ulalume3@67 | 1031 | **WARNING:** Please not that also *Raman/Elastic backscatter products* |
ulalume3@67 | 1032 | need to be linked to a calibration product because the calibration |
ulalume3@67 | 1033 | constant and the corresponding correction factor is needed to calculate |
ulalume3@67 | 1034 | the total signal out of the two polarization components even if the |
ulalume3@67 | 1035 | *PLDR* is not involved in the product calculation. |
ulalume3@67 | 1036 | |
ulalume3@67 | 1037 | .. |image0| image:: ./media/image1.png |
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ulalume3@67 | 1046 | .. |image3| image:: ./media/image4.png |
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