Appendix 1
The planar reciprocal distance model, Eq. (78), for the covariance function of the disturbing potential is repeated here for convenience with certain abbreviations
$${\varphi }_{T,T}\left ({s}_{1},{s}_{2};{z}_{1},{z}_{2}\right ) = \frac{{\sigma }^{2}} {{M}^{1\left /\right . 2}},$$
(A.1)
where
$$M = {\beta }^{2}+{\alpha }^{2}{s}^{2},\quad \beta = 1+\alpha \left ({z}_{ 1} + {z}_{2}\right ),\quad {s}^{2} = {s}_{ 1}^{2}+{s}_{ 1}^{2},\quad {s}_{ 1} = {x}_{1}-{x}_{1}^{{\prime}},\quad {s}_{ 2} = {x}_{2}-{x}_{2}^{{\prime}}.$$
(A.2)
The primed coordinates refer to the first subscripted function in the covariance and the unprimed coordinates refer to the second function. The altitude levels for these functions are z
1 and z
2, respectively. Derivatives of the disturbing potential with respect to the coordinates are denoted \(\partial T\left /\right . \partial {x}_{1} = {T}_{{x}_{1}}\), \({\partial }^{2}T\left /\right .\left (\partial {x}_{1}\partial z\right ) = {T}_{{x}_{1}z}\), etc. The following expressions for the cross-covariances are derived by repeatedly using Eqs. (40) and (52). The arguments for the resulting function are omitted, but are the same as in Eq. (1).
$$\begin{array}{rcl} &{\phi }_{{T}_{{x}_{ 1}},T} = \frac{{\sigma }^{2}{\alpha }^{2}{s}_{1}} {{M}^{3\left /\right . 2}} = -{\phi }_{T,{T}_{{x}_{ 1}}} \end{array}$$
(A.3)
$$\begin{array}{rcl} {\phi }_{{T}_{{x}_{ 2}},T} = \frac{{\sigma }^{2}{\alpha }^{2}{s}_{2}} {{M}^{3\left /\right . 2}} = -{\phi }_{T,{T}_{{x}_{ 2}}} \end{array}$$
(A.4)
$$\begin{array}{rcl} {\phi }_{{T}_{z},T} = -\frac{{\sigma }^{2}\alpha \beta } {{M}^{3\left /\right . 2}} = {\phi }_{T,{T}_{z}} \end{array}$$
(A.5)
$$\begin{array}{rcl} {\phi }_{{T}_{{x}_{ 1}},{T}_{{x}_{1}}} = \frac{{\sigma }^{2}{\alpha }^{2}} {{M}^{5\left /\right . 2}}\left (M - 3{\alpha }^{2}{s}_{ 1}^{2}\right ) \end{array}$$
(A.6)
$$\begin{array}{rcl} {\phi }_{{T}_{{x}_{ 1}},{T}_{{x}_{2}}} = -3 \frac{{\sigma }^{2}{\alpha }^{4}} {{M}^{5\left /\right . 2}}{s}_{1}{s}_{2} = {\phi }_{{T}_{{x}_{ 2}},{T}_{{x}_{1}}} \end{array}$$
(A.7)
$$\begin{array}{rcl} {\phi }_{{T}_{{x}_{ 1}},{T}_{z}} = -3\frac{{\sigma }^{2}{\alpha }^{3}\beta } {{M}^{5\left /\right . 2}} {s}_{1} = -{\phi }_{{T}_{z},{T}_{{x}_{ 1}}} \end{array}$$
(A.8)
$$\begin{array}{rcl} {\phi }_{{T}_{{x}_{ 2}},{T}_{{x}_{2}}} = \frac{{\sigma }^{2}{\alpha }^{2}} {{M}^{5\left /\right . 2}}\left (M - 3{\alpha }^{2}{s}_{ 2}^{2}\right ) \end{array}$$
(A.9)
$$\begin{array}{rcl} {\phi }_{{T}_{{x}_{ 2}},{T}_{z}} = -3\frac{{\sigma }^{2}{\alpha }^{3}\beta } {{M}^{5\left /\right . 2}} {s}_{2} = -{\phi }_{{T}_{z},{T}_{{x}_{ 2}}} \end{array}$$
(A.10)
$$\begin{array}{rcl} {\phi }_{{T}_{z},{T}_{z}} = \frac{{\sigma }^{2}{\alpha }^{2}} {{M}^{5\left /\right . 2}}\left (2M - 3{\alpha }^{2}{s}^{2}\right ) = {\phi }_{{ T}_{{x}_{1}},{T}_{{x}_{1}}} + {\phi }_{{T}_{{x}_{2}},{T}_{{x}_{2}}} \end{array}$$
(A.11)
$$\begin{array}{rcl} {\phi }_{T,{T}_{{x}_{ 1}{x}_{1}}} = -{\phi }_{{T}_{{x}_{ 1}},{T}_{{x}_{1}}} = {\phi }_{{T}_{{x}_{ 1}{x}_{1}},T} \end{array}$$
(A.12)
$$\begin{array}{rcl} {\phi }_{T,{T}_{{x}_{ 1}{x}_{2}}} = -{\phi }_{{T}_{{x}_{ 1}},{T}_{{x}_{2}}} = {\phi }_{{T}_{{x}_{ 1}{x}_{2}},T} \end{array}$$
(A.13)
$$\begin{array}{rcl} &{\phi }_{T,{T}_{{x}_{ 1}z}} = -{\phi }_{{T}_{{x}_{ 1}},{T}_{z}} = -{\phi }_{{T}_{{x}_{ 1}z},T} \end{array}$$
(A.14)
$$\begin{array}{rcl} {\phi }_{T,{T}_{{x}_{ 2}{x}_{2}}} = -{\phi }_{{T}_{{x}_{ 2}},{T}_{{x}_{2}}} = {\phi }_{{T}_{{x}_{ 2}{x}_{2}},T} \end{array}$$
(A.15)
$$\begin{array}{rcl} {\phi }_{T,{T}_{{x}_{ 2}z}} = -{\phi }_{{T}_{{x}_{ 2}},{T}_{z}} = -{\phi }_{{T}_{{x}_{ 2}z},T} \end{array}$$
(A.16)
$$\begin{array}{rcl} {\phi }_{T,{T}_{zz}} = {\phi }_{{T}_{z},{T}_{z}} = {\phi }_{{T}_{zz},T} \end{array}$$
(A.17)
$$\begin{array}{rcl} {\phi }_{{T}_{{x}_{ 1}},{T}_{{x}_{1}{x}_{1}}} = \frac{3{\sigma }^{2}{\alpha }^{4}{s}_{1}} {{M}^{7\left /\right . 2}} \left (-3M + 5{\alpha }^{2}{s}_{ 1}^{2}\right ) = -{\phi }_{{ T}_{{x}_{1}{x}_{1}},{T}_{{x}_{1}}} \end{array}$$
(A.18)
$$\begin{array}{rcl} {\phi }_{{T}_{{x}_{ 1}},{T}_{{x}_{1}{x}_{2}}} = \frac{3{\sigma }^{2}{\alpha }^{4}{s}_{2}} {{M}^{7\left /\right . 2}} \left (-M + 5{\alpha }^{2}{s}_{ 1}^{2}\right ) = -{\phi }_{{ T}_{{x}_{1}{x}_{2}},{T}_{{x}_{1}}} = {\phi }_{{T}_{{x}_{2}},{T}_{{x}_{1}{x}_{1}}} = -{\phi }_{{T}_{{x}_{1}{x}_{1}},{T}_{{x}_{2}}} \end{array}$$
(A.19)
$$\begin{array}{rcl} {\phi }_{{T}_{{x}_{ 1}},{T}_{{x}_{1}z}} = \frac{3{\sigma }^{2}{\alpha }^{3}\beta } {{M}^{7\left /\right . 2}} \left (-M + 5{\alpha }^{2}{s}_{ 1}^{2}\right ) = {\phi }_{{ T}_{{x}_{1}z},{T}_{{x}_{1}}} = -{\phi }_{{T}_{z},{T}_{{x}_{1}{x}_{1}}} = -{\phi }_{{T}_{{x}_{1}{x}_{1}},{T}_{z}} \end{array}$$
(A.20)
$$\begin{array}{rcl} {\phi }_{{T}_{{x}_{ 1}},{T}_{{x}_{2}{x}_{2}}} = \frac{3{\sigma }^{2}{\alpha }^{4}{s}_{2}} {{M}^{7\left /\right . 2}} \left (-M + 5{\alpha }^{2}{s}_{ 2}^{2}\right ) = -{\phi }_{{ T}_{{x}_{2}{x}_{2}},{T}_{{x}_{1}}} = {\phi }_{{T}_{{x}_{2}},{T}_{{x}_{1}{x}_{2}}} = -{\phi }_{{T}_{{x}_{1}{x}_{2}},{T}_{{x}_{2}}} \end{array}$$
(A.21)
$$\begin{array}{rcl} {\phi }_{{T}_{{x}_{ 1}},{T}_{{x}_{2}z}} = \frac{15{\sigma }^{2}{\alpha }^{3}\beta } {{M}^{7\left /\right . 2}} {s}_{1}{s}_{2} = {\phi }_{{T}_{{x}_{ 2}z},{T}_{{x}_{1}}} = -{\phi }_{{T}_{z},{T}_{{x}_{ 1}{x}_{2}}} = {\phi }_{{T}_{{x}_{ 2}},{T}_{{x}_{1}z}} = -{\phi }_{{T}_{{x}_{ 1}{x}_{2}},{T}_{z}} = {\phi }_{{T}_{{x}_{ 1}z},{T}_{{x}_{2}}}\end{array}$$
(A.22)
$$\begin{array}{rcl} {\phi }_{{T}_{{x}_{ 1}},{T}_{zz}} = \frac{3{\sigma }^{2}{\alpha }^{4}{s}_{1}} {{M}^{7\left /\right . 2}} \left (4{\beta }^{2} - {\alpha }^{2}{s}^{2}\right ) = -{\phi }_{{ T}_{zz},{T}_{{x}_{1}}} = -{\phi }_{{T}_{z},{T}_{{x}_{1}z}} = {\phi }_{{T}_{{x}_{1}z},{T}_{z}} \end{array}$$
(A.23)
$$\begin{array}{rcl} {\phi }_{{T}_{{x}_{ 2}},{T}_{{x}_{2}{x}_{2}}} = \frac{3{\sigma }^{2}{\alpha }^{4}{s}_{2}} {{M}^{7\left /\right . 2}} \left (-3M + 5{\alpha }^{2}{s}_{ 2}^{2}\right ) = -{\phi }_{{ T}_{{x}_{2}{x}_{2}},{T}_{{x}_{2}}} \end{array}$$
(A.24)
$$\begin{array}{rcl} {\phi }_{{T}_{{x}_{ 2}},{T}_{{x}_{2}z}} = \frac{3{\sigma }^{2}{\alpha }^{3}\beta } {{M}^{7\left /\right . 2}} \left (-M + 5{\alpha }^{2}{s}_{ 2}^{2}\right ) = {\phi }_{{ T}_{{x}_{2}z},{T}_{{x}_{2}}} = -{\phi }_{{T}_{z},{T}_{{x}_{2}{x}_{2}}} = -{\phi }_{{T}_{{x}_{2}{x}_{2}},{T}_{z}} \end{array}$$
(A.25)
$$\begin{array}{rcl} {\phi }_{{T}_{{x}_{ 2}},{T}_{zz}} = \frac{3{\sigma }^{2}{\alpha }^{4}{s}_{2}} {{M}^{7\left /\right . 2}} \left (4{\beta }^{2} - {\alpha }^{2}{s}^{2}\right ) = -{\phi }_{{ T}_{zz},{T}_{{x}_{2}}} = -{\phi }_{{T}_{z},{T}_{{x}_{2}z}} = {\phi }_{{T}_{{x}_{2}z},{T}_{z}} \end{array}$$
(A.26)
$$\begin{array}{rcl} {\phi }_{{T}_{z},{T}_{zz}} = \frac{3{\sigma }^{2}{\alpha }^{3}\beta } {{M}^{7\left /\right . 2}} \left (-2M + 5{\alpha }^{2}{s}^{2}\right ) = {\phi }_{{ T}_{zz},{T}_{z}} \end{array}$$
(A.27)
$$\begin{array}{rcl} {\phi }_{{T}_{{x}_{ 1}{x}_{1}},{T}_{{x}_{1}{x}_{1}}} = \frac{3{\sigma }^{2}{\alpha }^{4}} {{M}^{9\left /\right . 2}} \left (3{M}^{2} - 30M{\alpha }^{2}{s}_{ 1}^{2} + 35{\alpha }^{4}{s}_{ 1}^{4}\right ) \end{array}$$
(A.28)
$$\begin{array}{rcl} {\phi }_{{T}_{{x}_{ 1}{x}_{1}},{T}_{{x}_{1}{x}_{2}}} = \frac{15{\sigma }^{2}{\alpha }^{6}{s}_{1}{s}_{2}} {{M}^{9\left /\right . 2}} \left (-3M + 7{\alpha }^{2}{s}_{ 1}^{2}\right ) = {\phi }_{{ T}_{{x}_{1}{x}_{2}},{T}_{{x}_{1}{x}_{1}}} \end{array}$$
(A.29)
$$\begin{array}{rcl} {\phi }_{{T}_{{x}_{ 1}{x}_{1}},{T}_{{x}_{1}z}} = \frac{15{\sigma }^{2}{\alpha }^{5}\beta {s}_{1}} {{M}^{9\left /\right . 2}} \left (-3M + 7{\alpha }^{2}{s}_{ 1}^{2}\right ) = -{\phi }_{{ T}_{{x}_{1}{x}_{3}},{T}_{{x}_{1}{x}_{1}}} \end{array}$$
(A.30)
$$\begin{array}{rcl} {\phi }_{{T}_{{x}_{ 1}{x}_{1}},{T}_{{x}_{2}{x}_{2}}} = \frac{3{\sigma }^{2}{\alpha }^{4}} {{M}^{9\left /\right . 2}} \left ({M}^{2} - 5M{\alpha }^{2}{s}^{2} + 35{s}_{ 1}^{2}{s}_{ 2}^{2}\right ) = {\phi }_{{ T}_{{x}_{2}{x}_{2}},{T}_{{x}_{1}{x}_{1}}} = {\phi }_{{T}_{{x}_{1}{x}_{2}},{T}_{{x}_{1}{x}_{2}}} & \end{array}$$
(A.31)
$$\begin{array}{rcl} &{\phi }_{{T}_{{x}_{ 1}{x}_{1}},{T}_{{x}_{2}z}} = \frac{15{\sigma }^{2}{\alpha }^{5}\beta {s}_{2}} {{M}^{9\left /\right . 2}} \left (-M + 7{\alpha }^{2}{s}_{ 1}^{2}\right ) = -{\phi }_{{ T}_{{x}_{2}z},{T}_{{x}_{1}{x}_{1}}} = -{\phi }_{{T}_{{x}_{1}z},{T}_{{x}_{1}{x}_{2}}} = {\phi }_{{T}_{{x}_{1}{x}_{2}},{T}_{{x}_{1}z}} \end{array}$$
(A.32)
$$\begin{array}{rcl} {\phi }_{{T}_{{x}_{ 1}{x}_{1}},{T}_{zz}} = \frac{3{\sigma }^{2}{\alpha }^{4}} {{M}^{9\left /\right . 2}} \left (-4{M}^{2} + 5M{\alpha }^{2}{s}_{ 2}^{2} + 35{\beta }^{2}{\alpha }^{2}{s}_{ 1}^{2}\right ) = {\phi }_{{ T}_{zz},{T}_{{x}_{1}{x}_{1}}} = -{\phi }_{{T}_{{x}_{1}z},{T}_{{x}_{1}z}} \end{array}$$
(A.33)
$$\begin{array}{rcl} {\phi }_{{T}_{{x}_{ 1}{x}_{2}},{T}_{{x}_{2}{x}_{2}}} = \frac{15{\sigma }^{2}{\alpha }^{6}{s}_{1}{s}_{2}} {{M}^{9\left /\right . 2}} \left (-3M + 7{\alpha }^{2}{s}_{ 2}^{2}\right ) = {\phi }_{{ T}_{{x}_{2}{x}_{2}},{T}_{{x}_{1}{x}_{2}}} \end{array}$$
(A.34)
$$\begin{array}{rcl} {\phi }_{{T}_{{x}_{ 1}{x}_{2}},{T}_{{x}_{2}z}} = \frac{15{\sigma }^{2}{\alpha }^{5}\beta {s}_{1}} {{M}^{9\left /\right . 2}} \left (-M + 7{\alpha }^{2}{s}_{ 2}^{2}\right ) = -{\phi }_{{ T}_{{x}_{2}z},{T}_{{x}_{1}{x}_{2}}} = -{\phi }_{{T}_{{x}_{1}z},{T}_{{x}_{2}{x}_{2}}} = {\phi }_{{T}_{{x}_{2}{x}_{2}},{T}_{{x}_{1}z}}\end{array}$$
(A.35)
$$\begin{array}{rcl} {\phi }_{{T}_{{x}_{ 1}z},{T}_{zz}} = \frac{15{\sigma }^{2}{\alpha }^{5}\beta {s}_{1}} {{M}^{9\left /\right . 2}} \left (3M - 7{\beta }^{2}\right ) = -{\phi }_{{ T}_{zz},{T}_{{x}_{1}z}} \end{array}$$
(A.36)
$$\begin{array}{rcl} {\phi }_{{T}_{{x}_{ 2}{x}_{2}},{T}_{{x}_{2}{x}_{2}}} = \frac{3{\sigma }^{2}{\alpha }^{4}} {{M}^{9\left /\right . 2}} \left (3{M}^{2} - 30M{\alpha }^{2}{s}_{ 2}^{2} + 35{\alpha }^{4}{s}_{ 2}^{4}\right ) \end{array}$$
(A.37)
$$\begin{array}{rcl} {\phi }_{{T}_{{x}_{ 2}{x}_{2}},{T}_{{x}_{2}z}} = \frac{15{\sigma }^{2}{\alpha }^{5}\beta {s}_{2}} {{M}^{9\left /\right . 2}} \left (-3M + 7{\alpha }^{2}{s}_{ 2}^{2}\right ) = -{\phi }_{{ T}_{{x}_{2}z},{T}_{{x}_{2}{x}_{2}}} \end{array}$$
(A.38)
$$\begin{array}{rcl} {\phi }_{{T}_{{x}_{ 2}{x}_{2}},{T}_{zz}} = \frac{3{\sigma }^{2}{\alpha }^{4}} {{M}^{9\left /\right . 2}} \left (-4{M}^{2} + 5M{\alpha }^{2}{s}_{ 1}^{2} + 35{\beta }^{2}{\alpha }^{2}{s}_{ 2}^{2}\right ) = {\phi }_{{ T}_{zz},{T}_{{x}_{2}{x}_{2}}} = -{\phi }_{{T}_{{x}_{2}z},{T}_{{x}_{2}z}} \end{array}$$
(A.39)
$$\begin{array}{rcl} {\phi }_{{T}_{{x}_{ 2}z},{T}_{zz}} = \frac{15{\sigma }^{2}{\alpha }^{5}\beta {s}_{2}} {{M}^{9\left /\right . 2}} \left (3M - 7{\beta }^{2}\right ) = -{\phi }_{{ T}_{zz},{T}_{{x}_{2}z}} \end{array}$$
(A.40)
$$\begin{array}{rcl} {\phi }_{{T}_{zz},{T}_{zz}} = \frac{3{\sigma }^{2}{\alpha }^{4}} {{M}^{9\left /\right . 2}} \left (8{\beta }^{4} - 24{\beta }^{2}{\alpha }^{2}{s}^{2} + 3{\alpha }^{4}{s}^{4}\right ) = {\phi }_{{ T}_{{x}_{1}z},{T}_{{x}_{1}z}} + {\phi }_{{T}_{{x}_{2}z},{T}_{{x}_{2}z}}\end{array}$$
(A.41)
Appendix 2
The along-track PSD of the disturbing potential, given by Eq. (83), can be shown to be
$${S}_{T,T}\left ({f}_{1};{s}_{2};{z}_{1},{z}_{2}\right ) = \frac{2{\sigma }^{2}} {\alpha } {K}_{0}\left (2\pi {f}_{1}\,d\right ),$$
(B.1)
where K
0 is the modified Bessel function of the second kind and zero order, and
$$d = \sqrt{\frac{{\beta }^{2 } } {{\alpha }^{2}} + {s}_{2}^{2}}.$$
(B.2)
In the following along-track PSDs of the derivatives of T, also the modified Bessel function of the second kind and first order, K
1, appears. Both Bessel function always have the argument, 2Ï€f
1
d; and, the arguments of the along-track PSDs are the same as in Eq. (1).
$$\begin{array}{rcl} &{S}_{T,{T}_{{x}_{ 1}}} = i2\pi {f}_{1}{S}_{TT} = -{S}_{{T}_{{x}_{ 1}},T} \end{array}$$
(B.3)
$$\begin{array}{rcl} {S}_{T,{T}_{{x}_{ 2}}} = \frac{2{\sigma }^{2}\left (2\pi {f}_{1}\right ){s}_{2}} {\alpha d} {K}_{1} = -{S}_{{T}_{{x}_{ 2}},T} \end{array}$$
(B.4)
$$\begin{array}{rcl} {S}_{T,{T}_{z}} = -\frac{2{\sigma }^{2}\left (2\pi {f}_{1}\right )\beta } {{\alpha }^{2}d} {K}_{1} = {S}_{{T}_{z},T} \end{array}$$
(B.5)
$$\begin{array}{rcl} {S}_{{T}_{{x}_{ 1}},{T}_{{x}_{1}}} ={ \left (2\pi {f}_{1}\right )}^{2}{S}_{ TT} \end{array}$$
(B.6)
$$\begin{array}{rcl} {S}_{{T}_{{x}_{ 1}},{T}_{{x}_{2}}} = i2\pi {f}_{1}{S}_{{T}_{{x}_{ 2}},T} = {S}_{{T}_{{x}_{ 2}},{T}_{{x}_{1}}} \end{array}$$
(B.7)
$$\begin{array}{rcl} {S}_{{T}_{{x}_{ 1}},{T}_{z}} = -i2\pi {f}_{1}{S}_{T,{T}_{z}} = -{S}_{{T}_{z},{T}_{{x}_{ 1}}} \end{array}$$
(B.8)
$$\begin{array}{rcl} {S}_{{T}_{{x}_{ 2}},{T}_{{x}_{2}}} = \frac{2{\sigma }^{2}\left (2\pi {f}_{1}\right )} {\alpha d} \left (\left (1 -\frac{2{s}_{2}^{2}} {{d}^{2}} \right ){K}_{1} - 2\pi {f}_{1}\frac{{s}_{2}^{2}} {d} {K}_{0}\right ) \end{array}$$
(B.9)
$$\begin{array}{rcl} {S}_{{T}_{{x}_{ 2}},{T}_{z}} = -\frac{2{\sigma }^{2}\left (2\pi {f}_{1}\right )\beta {s}_{2}} {{\alpha }^{2}{d}^{3}} \left (2{K}_{1} + 2\pi {f}_{1}d\,{K}_{0}\right ) = -{S}_{{T}_{z},{T}_{{x}_{ 2}}} \end{array}$$
(B.10)
$$\begin{array}{rcl} {S}_{{T}_{z},{T}_{z}} = {S}_{{T}_{{x}_{ 1}},{T}_{{x}_{1}}} + {S}_{{T}_{{x}_{ 2}},{T}_{{x}_{2}}} \end{array}$$
(B.11)
$$\begin{array}{rcl} {S}_{T,{T}_{{x}_{ 1}{x}_{1}}} = -{S}_{{T}_{{x}_{ 1}},{T}_{{x}_{1}}} = {S}_{{T}_{{x}_{ 1}{x}_{1}},T} \end{array}$$
(B.12)
$$\begin{array}{rcl} {S}_{T,{T}_{{x}_{ 1}{x}_{2}}} = -{S}_{{T}_{{x}_{ 1}},{T}_{{x}_{2}}} = {S}_{{T}_{{x}_{ 1}{x}_{2}},T} \end{array}$$
(B.13)
$$\begin{array}{rcl} {S}_{T,{T}_{{x}_{ 1}z}} = -{S}_{{T}_{{x}_{ 1}},{T}_{z}} = -{S}_{{T}_{{x}_{ 1}z},T} \end{array}$$
(B.14)
$$\begin{array}{rcl} {S}_{T,{T}_{{x}_{ 2}{x}_{2}}} = -{S}_{{T}_{{x}_{ 2}},{T}_{{x}_{2}}} = {S}_{{T}_{{x}_{ 2}{x}_{2}},T} \end{array}$$
(B.15)
$$\begin{array}{rcl} {S}_{T,{T}_{{x}_{ 2}z}} = -{S}_{{T}_{{x}_{ 2}},{T}_{z}} = -{S}_{{T}_{{x}_{ 2}z},T} \end{array}$$
(B.16)
$$\begin{array}{rcl} {S}_{T,{T}_{zz}} = {S}_{{T}_{z},{T}_{z}} = {S}_{{T}_{zz},T} \end{array}$$
(B.17)
$$\begin{array}{rcl} {S}_{{T}_{{x}_{ 1}},{T}_{{x}_{1}{x}_{1}}} = i{\left (2\pi {f}_{1}\right )}^{3}{S}_{ T,T} = -{S}_{{T}_{{x}_{1}{x}_{1}},{T}_{{x}_{1}}} \end{array}$$
(B.18)
$$\begin{array}{rcl} {S}_{{T}_{{x}_{ 1}},{T}_{{x}_{1}{x}_{2}}} = \left (2\pi {f}_{1}\right ){S}_{T,{T}_{{x}_{ 2}}} = -{S}_{{T}_{{x}_{ 1}{x}_{2}},{T}_{{x}_{1}}} = {S}_{{T}_{{x}_{ 2}},{T}_{{x}_{1}{x}_{1}}} = -{S}_{{T}_{{x}_{ 1}{x}_{1}},{T}_{{x}_{2}}} \end{array}$$
(B.19)
$$\begin{array}{rcl} {S}_{{T}_{{x}_{ 1}},{T}_{{x}_{1}z}} ={ \left (2\pi {f}_{1}\right )}^{2}{S}_{ T,{T}_{z}} = {S}_{{T}_{{x}_{1}z},{T}_{{x}_{1}}} = -{S}_{{T}_{z},{T}_{{x}_{1}{x}_{1}}} = -{S}_{{T}_{{x}_{1}{x}_{1}},{T}_{z}}\end{array}$$
(B.20)
$$\begin{array}{rcl} &{S}_{{T}_{{x}_{ 1}},{T}_{{x}_{2}{x}_{2}}} = i2\pi {f}_{1}\,{S}_{{T}_{{x}_{ 2}},{T}_{{x}_{2}}} = -{S}_{{T}_{{x}_{ 2}{x}_{2}},{T}_{{x}_{1}}} = {S}_{{T}_{{x}_{ 2}},{T}_{{x}_{1}{x}_{2}}} = -{S}_{{T}_{{x}_{ 1}{x}_{2}},{T}_{{x}_{2}}} \end{array}$$
(B.21)
$$\begin{array}{rcl} {S}_{{T}_{{x}_{ 1}},{T}_{{x}_{2}z}} = i2\pi {f}_{1}\,{S}_{{T}_{{x}_{ 2}},{T}_{z}} = {S}_{{T}_{{x}_{ 2}z},{T}_{{x}_{1}}} = -{S}_{{T}_{z},{T}_{{x}_{ 1}{x}_{2}}} = {S}_{{T}_{{x}_{ 2}},{T}_{{x}_{1}z}} = -{S}_{{T}_{{x}_{ 1}{x}_{2}},{T}_{z}} = {S}_{{T}_{{x}_{ 1}z},{T}_{{x}_{2}}}\end{array}$$
(B.22)
$$\begin{array}{rcl} {S}_{{T}_{{x}_{ 1}},{T}_{zz}} = -i2\pi {f}_{1}\,{S}_{{T}_{z},{T}_{z}} = -{S}_{{T}_{zz},{T}_{{x}_{ 1}}} = -{S}_{{T}_{z},{T}_{{x}_{ 1}z}} = {S}_{{T}_{{x}_{ 1}z},{T}_{z}} \end{array}$$
(B.23)
$$\begin{array}{rcl} {S}_{{T}_{{x}_{2}},{T}_{{x}_{2}{x}_{2}}} & = -\frac{2{\sigma }^{2}\left (2\pi {f}_{ 1}\right ){s}_{2}} {\alpha {d}^{3}} \left (\left (6 -\frac{8{s}_{2}^{2}} {{d}^{2}} -{\left (2\pi {f}_{1}\,{s}_{2}\right )}^{2}\right ){K}_{1} + 2\pi {f}_{1}\,d\left (3 -\frac{4{s}_{2}^{2}} {{d}^{2}} \right ){K}_{0}\right ) \\ & = -{S}_{{T}_{{x}_{ 2}{x}_{2}},{T}_{{x}_{2}}} \end{array}$$
(B.24)
$$\begin{array}{rcl} {S}_{{T}_{{x}_{2}},{T}_{{x}_{2}z}} & = -\frac{2{\sigma }^{2}\left (2\pi {f}_{ 1}\right )\beta } {{\alpha }^{2}{d}^{3}} \left (\left (2 -\frac{8{s}_{2}^{2}} {{d}^{2}} -{\left (2\pi {f}_{1}\,{s}_{2}\right )}^{2}\right ){K}_{1} + 2\pi {f}_{1}\,d\left (1 -\frac{4{s}_{2}^{2}} {{d}^{2}} \right ){K}_{0}\right ) \\ & = {S}_{{T}_{{x}_{ 2}z},{T}_{{x}_{2}}} = -{S}_{{T}_{z},{T}_{{x}_{ 2}{x}_{2}}} = -{S}_{{T}_{{x}_{ 2}{x}_{2}},{T}_{z}} \end{array}$$
(B.25)
$$\begin{array}{rcl} {S}_{{T}_{{x}_{ 2}},{T}_{zz}} = -{S}_{{T}_{{x}_{ 2}},{T}_{{x}_{1}{x}_{1}}} - {S}_{{T}_{{x}_{ 2}},{T}_{{x}_{2}{x}_{2}}} = -{S}_{{T}_{zz},{T}_{{x}_{ 2}}} = -{S}_{{T}_{z},{T}_{{x}_{ 2}z}} = {S}_{{T}_{{x}_{ 2}z},{T}_{z}} \end{array}$$
(B.26)
$$\begin{array}{rcl} {S}_{{T}_{z},{T}_{zz}} = {S}_{{T}_{{x}_{ 1}},{T}_{{x}_{1}z}} + {S}_{{T}_{{x}_{ 2}},{T}_{{x}_{2}z}} = {S}_{{T}_{zz},{T}_{z}} \end{array}$$
(B.27)
$$\begin{array}{rcl} {S}_{{T}_{{x}_{ 1}{x}_{1}},{T}_{{x}_{1}{x}_{1}}} ={ \left (2\pi {f}_{1}\right )}^{4}{S}_{ T,T} \end{array}$$
(B.28)
$$\begin{array}{rcl} {S}_{{T}_{{x}_{ 1}{x}_{1}},{T}_{{x}_{1}{x}_{2}}} = i{\left (2\pi {f}_{1}\right )}^{3}{S}_{{ T}_{{x}_{2}},T} = {S}_{{T}_{{x}_{1}{x}_{2}},{T}_{{x}_{1}{x}_{1}}} \end{array}$$
(B.29)
$$\begin{array}{rcl} {S}_{{T}_{{x}_{ 1}{x}_{1}},{T}_{{x}_{1}z}} = -i{\left (2\pi {f}_{1}\right )}^{3}{S}_{ T,{T}_{z}} = -{S}_{{T}_{{x}_{1}z},{T}_{{x}_{1}{x}_{1}}} \end{array}$$
(B.30)
$$\begin{array}{rcl} {S}_{{T}_{{x}_{ 1}{x}_{1}},{T}_{{x}_{2}{x}_{2}}} ={ \left (2\pi {f}_{1}\right )}^{2}{S}_{{ T}_{{x}_{2}},{T}_{{x}_{2}}} = {S}_{{T}_{{x}_{2}{x}_{2}},{T}_{{x}_{1}{x}_{1}}} = {S}_{{T}_{{x}_{1}{x}_{2}},{T}_{{x}_{1}{x}_{2}}} \end{array}$$
(B.31)
$$\begin{array}{rcl} {S}_{{T}_{{x}_{ 1}{x}_{1}},{T}_{{x}_{2}z}} ={ \left (2\pi {f}_{1}\right )}^{2}{S}_{{ T}_{{x}_{2}},{T}_{z}} = -{S}_{{T}_{{x}_{2}z},{T}_{{x}_{1}{x}_{1}}} = -{S}_{{T}_{{x}_{1}z},{T}_{{x}_{1}{x}_{2}}} = {S}_{{T}_{{x}_{1}{x}_{2}},{T}_{{x}_{1}z}} \end{array}$$
(B.32)
$$\begin{array}{rcl} {S}_{{T}_{{x}_{ 1}{x}_{1}},{T}_{zz}} = -{\left (2\pi {f}_{1}\right )}^{2}{S}_{{ T}_{z},{T}_{z}} = {S}_{{T}_{zz},{T}_{{x}_{1}{x}_{1}}} = -{S}_{{T}_{{x}_{1}z},{T}_{{x}_{1}z}} \end{array}$$
(B.33)
$$\begin{array}{rcl} {S}_{{T}_{{x}_{ 1}{x}_{2}},{T}_{{x}_{2}{x}_{2}}} = i2\pi {f}_{1}\,{S}_{{T}_{{x}_{ 2}{x}_{2}},{T}_{{x}_{2}}} = {S}_{{T}_{{x}_{ 2}{x}_{2}},{T}_{{x}_{1}{x}_{2}}} \end{array}$$
(B.34)
$$\begin{array}{rcl} {S}_{{T}_{{x}_{ 1}{x}_{2}},{T}_{{x}_{2}z}} = -i2\pi {f}_{1}\,{S}_{{T}_{{x}_{ 2}},{T}_{{x}_{2}z}} = -{S}_{{T}_{{x}_{ 2}z},{T}_{{x}_{1}{x}_{2}}} = -{S}_{{T}_{{x}_{ 1}z},{T}_{{x}_{2}{x}_{2}}} = {S}_{{T}_{{x}_{ 2}{x}_{2}},{T}_{{x}_{1}z}} \end{array}$$
(B.35)
$$\begin{array}{rcl} {S}_{{T}_{{x}_{ 1}{x}_{2}},{T}_{zz}} = -i2\pi {f}_{1}\,{S}_{{T}_{{x}_{ 2}z},{T}_{z}} = {S}_{{T}_{zz},{T}_{{x}_{ 1}{x}_{2}}} = -{S}_{{T}_{{x}_{ 1}z},{T}_{{x}_{2}z}} = -{S}_{{T}_{{x}_{ 2}z},{T}_{{x}_{1}z}}\end{array}$$
(B.36)
$$\begin{array}{rcl} &{S}_{{T}_{{x}_{ 1}z},{T}_{zz}} = {S}_{{T}_{{x}_{ 1}{x}_{1}},{T}_{{x}_{1}z}} + {S}_{{T}_{{x}_{ 2}{x}_{2}},{T}_{{x}_{1}z}} = -{S}_{{T}_{zz},{T}_{{x}_{ 1}z}} \end{array}$$
(B.37)
$$\begin{array}{rcl} {S}_{{T}_{{x}_{ 2}{x}_{2}},{T}_{{x}_{2}{x}_{2}}}& = \frac{2{\sigma }^{2}\left (2\pi {f}_{1}\right )} {\alpha {d}^{3}} \left (2\pi {f}_{1}\,d\left (3 -\frac{24{s}_{2}^{2}} {{d}^{2}} + \frac{24{s}_{2}^{4}} {{d}^{4}} +{ \left (2\pi {f}_{1}\,{s}_{2}\right )}^{2}\frac{{s}_{2}^{2}} {{d}^{2}} \right ){K}_{0}\right . \\ &\quad \left .+2\left (3 -\frac{24{s}_{2}^{2}} {{d}^{2}} - 3{\left (2\pi {f}_{1}{s}_{2}\right )}^{2} + \frac{24{s}_{2}^{4}} {{d}^{4}} + 4{\left (2\pi {f}_{1}\,{s}_{2}\right )}^{2}\frac{{s}_{2}^{2}} {{d}^{2}} \right ){K}_{1}\right ) \end{array}$$
(B.38)
$$\begin{array}{rcl} {S}_{{T}_{{x}_{ 2}{x}_{2}},{T}_{{x}_{2}z}} & = -\frac{2{\sigma }^{2}\left (2\pi {f}_{1}\right )\beta {s}_{2}} {{\alpha }^{2}{d}^{5}} \left (2\pi {f}_{1}\,d\left (12 -\frac{24{s}_{2}^{2}} {{d}^{2}} -{\left (2\pi {f}_{1}\,{s}_{2}\right )}^{2}\right ){K}_{ 0}\right . \\ &\quad \left .+\left (24 -\frac{48{s}_{2}^{2}} {{d}^{2}} + 3{\left (2\pi {f}_{1}d\right )}^{2} - 8{\left (2\pi {f}_{ 1}\,{s}_{2}\right )}^{2}\right ){K}_{ 1}\right ) \\ & = -{S}_{{T}_{{x}_{ 2}z},{T}_{{x}_{2}{x}_{2}}} \end{array}$$
(B.39)
$$\begin{array}{rcl} {S}_{{T}_{{x}_{ 2}{x}_{2}},{T}_{zz}} = -{S}_{{T}_{{x}_{ 1}{x}_{1}},{T}_{{x}_{2}{x}_{2}}} - {S}_{{T}_{{x}_{ 2}{x}_{2}},{T}_{{x}_{2}{x}_{2}}} = {S}_{{T}_{zz},{T}_{{x}_{ 2}{x}_{2}}} = -{S}_{{T}_{{x}_{ 2}z},{T}_{{x}_{2}z}}\end{array}$$
(B.40)
$$\begin{array}{rcl} {S}_{{T}_{{x}_{ 2}z},{T}_{zz}} = {S}_{{T}_{{x}_{ 1}{x}_{1}},{T}_{{x}_{2}z}} + {S}_{{T}_{{x}_{ 2}{x}_{2}},{T}_{{x}_{2}z}} = -{S}_{{T}_{zz},{T}_{{x}_{ 2}z}} \end{array}$$
(B.41)
$$\begin{array}{rcl} {S}_{{T}_{zz},{T}_{zz}} = {S}_{{T}_{{x}_{ 1}z},{T}_{{x}_{1}z}} + {S}_{{T}_{{x}_{ 2}z},{T}_{{x}_{2}z}}\end{array}$$
(B.42)