docs/depolarization/depolarization.rst

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52 52
53 For what it concerns the method c) it, basically, requires to solve the equation: 53 For what it concerns the method c) it, basically, requires to solve the equation:
54 54
55 .. math:: 55 .. math::
56 \alpha_s P_s + \alpha_p P_p = P 56 \alpha_s P_s + \alpha_p P_p = P
57 :label: eq_totsig
57 58
58 in two different atmospheric layers with considerably different *VLDR*. So to calibrate in this way the implementation of automatic layer identification in the SCC is required. As at moment this feature is not yet available within the SCC **ONLY** the method b) is considered. 59 in two different atmospheric layers with considerably different *VLDR*. So to calibrate in this way the implementation of automatic layer identification in the SCC is required. As at moment this feature is not yet available within the SCC **ONLY** the method b) is considered.
59 60
60 1.3 SCC procedure to calculate the PLDRP 61 1.3 SCC procedure to calculate the PLDRP
61 ---------------------------------------- 62 ----------------------------------------
97 98
98 In case of +45 calibration method :math:`\eta^*` is calculated by: 99 In case of +45 calibration method :math:`\eta^*` is calculated by:
99 100
100 .. math:: 101 .. math::
101 \eta^* = \frac{I_R}{I_T}(+45) 102 \eta^* = \frac{I_R}{I_T}(+45)
103 :label: eq_eta1
102 104
103 While in case of :math:`\Delta90` calibration method: 105 While in case of :math:`\Delta90` calibration method:
104 106
105 .. math:: 107 .. math::
106 \eta^* = \sqrt{\frac{I_R}{I_T}(+45) \frac{I_R}{I_T}(-45)} 108 \eta^* = \sqrt{\frac{I_R}{I_T}(+45) \frac{I_R}{I_T}(-45)}
109 :label: eq_eta2
107 110
108 **ELDA** module calculates the “apparent” *VLDR*: 111 **ELDA** module calculates the “apparent” *VLDR*:
109 112
110 .. math:: 113 .. math::
111 \delta^* = \frac{K}{\eta^*} \cdot \frac{I_R}{I_T} 114 \delta^* = \frac{K}{\eta^*} \cdot \frac{I_R}{I_T}
115 :label: eq_delta1
112 116
113 the *VLDR* 117 the *VLDR*
114 118
115 .. math:: 119 .. math::
116 \delta = \frac{\delta^*(G_T + H_T)-(G_R + H_R)}{(G_R - H_R) - \delta^*(G_T - H_T)} 120 \delta = \frac{\delta^*(G_T + H_T)-(G_R + H_R)}{(G_R - H_R) - \delta^*(G_T - H_T)}
121 :label: eq_delta2
117 122
118 and the *PLDR* 123 and the *PLDR*
119 124
120 .. math:: 125 .. math::
121 \delta_{\alpha} = \frac{(1 + \delta_m)\delta R - (1 + \delta)\delta_m}{(1 + \delta_m)R - (1 + \delta)} 126 \delta_{\alpha} = \frac{(1 + \delta_m)\delta R - (1 + \delta)\delta_m}{(1 + \delta_m)R - (1 + \delta)}
127 :label: eq_pldr
122 128
123 where: 129 where:
124 130
125 - :math:`\eta^*` is the *apparent calibration factor* calculated by **ELDEC** 131 - :math:`\eta^*` is the *apparent calibration factor* calculated by **ELDEC**
126 132
138 144
139 In order to retrieve the backscatter profile the total signal must be obtained combining the transmitted and reflected polarized signals. The following formula is used: 145 In order to retrieve the backscatter profile the total signal must be obtained combining the transmitted and reflected polarized signals. The following formula is used:
140 146
141 .. math:: 147 .. math::
142 I_{total} \propto \frac{\frac{\eta^*}{K}H_R I_T - H_T I_R}{H_R G_T - H_T G_R} 148 I_{total} \propto \frac{\frac{\eta^*}{K}H_R I_T - H_T I_R}{H_R G_T - H_T G_R}
149 :label: eq_Itot
143 150
144 The formulas above are general and can be adapted to all possible polarization lidar configurations selecting the right polarization cross-talk correction parameters (see Table 1.1). 151 The formulas above are general and can be adapted to all possible polarization lidar configurations selecting the right polarization cross-talk correction parameters (see Table 1.1).
145 152
146 Let's suppose, for example, we have the perpendicular polarized lidar signal on the transmitted channel and the parallel polarized on reflected channel. For an ideal system (no diattenuation and cross-talk) we have: 153 Let's suppose, for example, we have the perpendicular polarized lidar signal on the transmitted channel and the parallel polarized on reflected channel. For an ideal system (no diattenuation and cross-talk) we have:
147 154

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