subroutine zhaocarr_precpd::zhaocarr_precpd_run | ( | integer, intent(in) | im, |
integer, intent(in) | ix, | ||
integer, intent(in) | km, | ||
real (kind=kind_phys), intent(in) | dt, | ||
real (kind=kind_phys), dimension(ix,km), intent(in) | del, | ||
real (kind=kind_phys), dimension(ix,km), intent(in) | prsl, | ||
real (kind=kind_phys), dimension(ix,km), intent(inout) | q, | ||
real (kind=kind_phys), dimension(ix,km), intent(inout) | cwm, | ||
real (kind=kind_phys), dimension(ix,km), intent(inout) | t, | ||
real (kind=kind_phys), dimension(im), intent(out) | rn, | ||
real (kind=kind_phys), dimension(im), intent(out) | sr, | ||
real (kind=kind_phys), dimension(im,km), intent(out) | rainp, | ||
real (kind=kind_phys), dimension(im,km), intent(in) | u00k, | ||
real (kind=kind_phys), dimension(2), intent(in) | psautco, | ||
real (kind=kind_phys), dimension(2), intent(in) | prautco, | ||
real (kind=kind_phys), intent(in) | evpco, | ||
real (kind=kind_phys), dimension(2), intent(in) | wminco, | ||
real (kind=kind_phys), dimension(im), intent(in) | wk1, | ||
logical, intent(in) | lprnt, | ||
integer, intent(in) | jpr, | ||
character(len=*), intent(out) | errmsg, | ||
integer, intent(out) | errflg | ||
) |
\[ cwm > \min (wmin, wmini) \]
where the cloud water and ice conversion threshold:\[ wmin=wminco(1)\times prsl\times 10^{-5} \]
\[ wmini=wminco(2)\times prsl\times 10^{-5} \]
\[ P_{saut}=a_{1}(cwm-wmini) \]
Since snow production in this process is caused by the increase in size of cloud ice particles due to depositional growth and aggregation of small ice particles, \(P_{saut}\) is a function of temperature as determined by coefficient \(a_{1}\), given by\[ a_{1}=psautco \times dt \times exp\left[ 0.025\left(T-273.15\right)\right] \]
\[ P_{saci}=C_{s}cwm P_{s} \]
where \(P_{s}\) is the precipitation rate of snow. The collection coefficient \(C_{s}\) is a function of temperature since the open structures of ice crystals at relative warm temperatures are more likely to stick, given a collision, than crystals of other shapes (Rogers (1979) [90]). Above the freezing level, \(C_{s}\) is expressed by\[ C_{s}=c_{1}exp\left[ 0.025\left(T-273.15\right)\right] \]
where \(c_{1}=1.25\times 10^{-3} m^{2}kg^{-1}s^{-1}\) are used. \(C_{s}\) is set to zero below the freezing level.\[ P_{raut}=(prautco \times dt )\times (cwm-wmin)\left\{1-exp[-(\frac{cwm-wmin}{m_{r}b})^{2}]\right\} \]
where \(m_{r}\) is \(3.0\times 10^{-4}\).\[ E_{rr}= evpco \times (u-f)(P_{r})^{\beta} \]
where \(u\) is u00k, \(f\) is the relative humidity. \(\beta = 0.5\) are empirical parameter.\[ E_{rs}=[C_{rs1}+C_{rs2}(T-273.15)](\frac{u-f}{u})P_{s} \]
where \(C_{rs1}=5\times 10^{-6}m^{2}kg^{-1}s^{-1}\) and \(C_{rs2}=6.67\times 10^{-10}m^{2}kg^{-1}K^{-1}s^{-1}\). The evaporation of melting snow below the freezing level is ignored in this scheme because of the difficulty in the latent heat treatment since the surface of a melting snowflake is usually covered by a thin layer of liquid water.\[ P_{sm1}=C_{sm}(T-273.15)^{2}P_{s} \]
where \(C_{sm}=5\times 10^{-8}m^{2}kg^{-1}K^{-2}s^{-1}\) cause the falling snow to melt almost completely before it reaches the \(T=278.15 K\) level.\[ P_{sacw}=C_{r}cwmP_{s} \]
where \(C_{r}\) is the collection coefficient, \(C_{r}=5.0\times 10^{-4}m^{2}kg^{-1}s^{-1}\) . The melting rate of snow then can be computed from\[ P_{sm2}=C_{ws}P_{sacw} \]
where \(C_{ws}=0.025\).\[ t=t-\frac{L}{C_{p}}(E_{rr}+E_{rs}+P_{sm1})\times dt \]
\[ q=q+(E_{rr}+E_{rs})\times dt \]
\[ rn= (P_{r}(\eta_{sfc})+P_{s}(\eta_{sfc}))/10^3 \]
\[ sr=\frac{P_{s}(\eta_{sfc})}{P_{s}(\eta_{sfc})+P_{r}(\eta_{sfc})} \]
References physcons::con_cp, physcons::con_eps, physcons::con_epsm1, physcons::con_g, physcons::con_hfus, physcons::con_hvap, physcons::con_ttp, and funcphys::fpvs().