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  $$R_0= 10^8 {\rm cm}$$
  
  
  
  
  $$C_0 = 0.4 {\rm H}$$
  
  
  
  
  $$w_0 = 0$$
  
  
  $B$rM?$($?$b$N$G$"$k(B. $B?^(B3$B$N2
  $$R_0= 10^8 {\rm cm}$$
  
  
  
  
  $$C_0 = 0.2 {\rm H}$$
  
  
  
  
  $$w_0 = \frac{0.2}{\tau} {\rm H}$$
  
  
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$B?^(B5 $B:=$NM"Aw2aDx(B(Earthlike plnet)

• Iversen et al(1976)$B$K$h$k Iverson et al(1976)$B$OIwF6 $B$N<0$r
  $$U^*_{min} = A \times \sqrt{\frac{(\rho_p - \rho)g D_p}{\rho}}$$
  
  
  $B$?$@$7(B, A$B$O(B
  
  $$B \equiv \frac{U^*_{min} D_p}{\nu}$$
  
  
  $B$NCM$K$h$C$F
  $$A = 0.266 \sqrt{\frac{1+\frac{0.055}{\rho g D^2_p}}{1+2.123B}} \ \ \ {\rm if} \ B \leq 0.22$$
  
  
  
  
  $$A = (0.108+\frac{0.0323}{B}-\frac{0.00173}{B^2}) (1+\frac{... ...g D^2_p})^{\frac{1}{2}} \ \ \ {\rm if} \ 0.22 \leq B \leq 10$$
  
  
  
  
  $$A = 0.11 \ \ \ {\rm if} \ B \geq 10$$
  
  
  $B$3$3$G(B, $D_p$ $B$O:=$ND>7B(B, $g$ $B$O=ENO2CB.EY(B, $\rho$ $B$O6u5$$NL)EY(B, $\rho_p$ $B$O:=$NL)EY(B, $\nu$ $B$OF1G4@-78?t$r(B, $B$=$l$>$l$"$i$o$9(B. $B$3$N7k2L$r?^$K$7$?$N$,?^(B6$B$G$"$k(B. $B?^(B5$B$N2#<4$O:=$ND>7B(B($\mu$ m)$B$r=D<4$O(B $U^*_{min}$ (cm/sec)$B$r$"$i$o$9(B. $BCO5e(B, $B2P@1(B, $B6b@1$N(B3$B$D$N>l9g$K$D$$$F<($7$F$"$k(B. $B$^$?;29M$N$?$a$K?eCf$NCf$NN3;R$N>l9g$K$D$$$F$N7k2L$b<($7$F$"$k(B. $B$3$N?^$+$i:G$b(B saltation $B$N5/$3$j$d$9$$N37B$,B8:_$9$k$3$H$,$o$+$k(B.
  
  $B?^(B6 $B:=$r4,$->e$2$k$N$KI,MW$JIwB.(B(Iversen et al(1976), fig 6)
  
  
  

• Gierasch and Goody(1973)$B$K$h$k5DO@(B

  Bagnold(1941)$B$N9M;!$K$h$k$H(B saltation $B$,5/$-$k$N$K:GDc8BI,MW$J(B friction velocity: $U^{*}_{min}$ $B$O(B
  

  $$U^{*}_{min} = 1.2 \times 10^{-2} \times \frac{\rho_{p} g \nu}{\rho}$$
  
  
  $B$GM?$($i$l$k(B. $BJQ?t$NDj5A$O>e$HF1$8(B. $B$3$l$r2P@1$N>l9g(B(200K, 6mb)$B$K7W;;$9$k$H(B
  
  $$U^{*}_{min} = 180 {\rm cm/sec}$$
  
  
  $B$H$J$k(B.

  $B;29M$^$G$K$3$N(B friction velocity $B$KBP1~$9$kCO9UIw$NB.EY$r5a$a$F$_$k(B. Csanady(1967)$B$K$h$l$P(B
  

  $$\left( \frac{U^{*}}{U_g} \right)^2 = C_{d}$$
  
  
  $B$H$J$k(B. $B$?$@$7(B, $U_{g}$$B$O(B geostrophic free-steam velocity $B$G$"$j(B, $C_{d}$ $B$ODq9378?t(B (drag coefficient) $B$G$"$k(B. Leovy and Mintz(1969) $B$O(B $C_{d}$ $B$r
  $$\sqrt{C_{d}} = 3 \times 10^{-2} \ : \mbox{stable}$$
  
  
  
  
  $$\sqrt{C_{d}} = 6 \times 10^{-2} \ : \mbox{unstable}$$
  
  
  $\sqrt{C_{d}} = 6 \times 10^{-2}$ $B$NCM$r;H$&$H(B, $B:=$r4,$->e$2$k$N$KI,MW$J(B $U_{g}$ $B$O(B
  
  $$U_{g} = 30 {\rm m/sec}$$
  
  
  $B$H5a$^$k(B. $B$3$l$G2P@1$G:=$r4,$->e$2$k$N$KI,MW$JCO9UIwB.EY$,5a$^$C$?(B. $BCO9UIw$NB.EY$H$7$F(B, 30 m/sec $B$H$$$&CM$O2P@1$G$O7h$7$F(B $BBg$-$$$b$N$G$O$J$$(B. $B$h$C$F(B, $B2P@1$GIQHK$K%@%9%H%9%H!<%`$,5/$-$k$N$bG

$B;29MJ88%(B

Gierasch, P.J. and Goody, R.M., 1973: A model of a Martian great dust storm, J. Atmos. Sci., 30, 169-179.

Iversen, J.D. et al., 1976: Windblown dust on Earth, Mars, Venus, J. Atmos. Sci., 33, 2425-2429.

Leovy, C.B. et al., 1973: Mechanism for Mars dust storm, J.Atmos.Sci., 30, 749-762.

Leovy, C.B., 1979: Martian Meteorology, Ann. Rev. Astron. Astrophys., 17, 387-413.

Murray, B.C., 1981: Earthlike planets. Freeman and Co., 387pp.

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