气象编程 | 水汽通量：水汽通量散度(Moisture Flux Convergence)以及垂直积分
气象编程 | 水汽通量：水汽通量散度(Moisture Flux Convergence)以及垂直积分
MeteoAI
发布于 2020-12-22 15:19:03
发布于 2020-12-22 15:19:03
文章被收录于专栏：MeteoAI
mfc_div_1.ncl: Calculate various divergence and moisture quantities including Vertically Integrated Moisture Flux Convergence (VIMFC). VIMFC has a high correlation with frontal and convective activity. Positive values indicate net precipitation. The following equation is implemented within mfc_div_1.ncl
This example uses uv2dvF_Wrap [uv2dvF] because the grid is a global fixed grid. For global gaussian, uv2dvG_Wrap [uv2dvG] should be used. For a regional grid uv2dv_cfd should be used.
mfc_div_1.ncl
;*************************************************
; mfc_div_1.ncl
;
; Concepts illustrated:
; - Read daily mean wind components, humidity and sfc. pressure
; from different files
; - Reorder the input (N==>S) grid order to (S==>N) via NCL syntax ::-1
; - Calculate mass weightined layer thickness [units="kg/m2"]
; - Calculate moisture flux [uq, vq]
; - Calculate moisture flux divergence using spherical harmonics
; - Integrate the moisture flux divergence using mass weighting
; - Plot a number of quantities
;*************************************************
;---Calculate the Horizontal Moisture Flux Convergence [MFC]
;*************************************************
;---High frequency source data: hourly/3hr/6hr/12hr/daily .... NOT monthly values
;---References:
;---http://www.cgd.ucar.edu/cas/catalog/newbudgets/
;---http://tornado.sfsu.edu/geosciences/classes/e260/AtmosphericRivers/Moisture%20Flux.pdf
;---https://www.spc.noaa.gov/publications/banacos/mfc-sls.pdf
;===================================================================
; Data Source: ESRL Physical Sciences Division
; https://www.esrl.noaa.gov/psd/data/gridded/data.ncep.reanalysis.html
; NCEP Reanalysis data provided by the NOAA/OAR/ESRL PSD, Boulder, Colorado, USA,
; from their Web site at https://www.esrl.noaa.gov/psd/
;===================================================================
ptop = 300 ; 'shum' upper level
ptop@units = "hPa"
g = 9.80665 ; m/s2
date = 20080715 ; NH summer
;---ESRL: CDC data
diri = "./"
filq = "shum.2008.nc" ; daily data for current year [366 days]
filu = "uwnd.2008.nc"
filv = "vwnd.2008.nc"
filps= "pres.sfc.2008.nc"
pthu = diri+filu
pthv = diri+filv
pthq = diri+filq
pthps= diri+filps
fu = addfile(pthu ,"r")
fv = addfile(pthv ,"r")
fq = addfile(pthq ,"r")
fps = addfile(pthps,"r")
;---Time
ymd = cd_calendar(fu->time, -2) ; ymd[*]: human readable
nt = ind(ymd.eq.date) ; date for plotting and testing
TEST = True
if (.not.TEST) then ; all times
u = fu->uwnd(:,{1000:ptop},:,:) ; m/s, (time,level,lat,lon)
v = fv->vwnd(:,{1000:ptop},:,:)
q = fq->shum ; [kg/kg], 1000-300 levels only
ps = fps->pres ; Pa=>[kg/(m-s2)], (time,lat,lon)
else ; one time step; keep time dimension [ nt:nt: ]
u = fu->uwnd(nt:nt,{1000:ptop},:,:); m/s, (time,level,lat,lon)
v = fv->vwnd(nt:nt,{1000:ptop},:,:)
q = fq->shum(nt:nt,:,:,:) ; [kg/kg], 1000-300 levels only
ps = fps->pres(nt:nt,:,:) ; Pa=>[kg/(m-s2)], (time,lat,lon)
nt = 0 ; only one time step
end if
;---Vertical levels
ptop = ptop*100
ptop@units = "Pa"
plev = q&level ; hPa
plev = plev*100 ; [100000,...,30000] Pa [kg/(m-s2)]
plev@units = "Pa"
;---Change [kg/kg] to [g/kg]; not necessary: but common units for q
q = q*1000
q@units = "g/kg"
;---Divergence function [used later] requires S->N grid order
u = u(:,:,::-1,:)
v = v(:,:,::-1,:)
q = q(:,:,::-1,:)
ps =ps(:, ::-1,:)
;---Layer thickness: ; Pa=>[kg/(m-s2)], (time,level,lat,lon)
;---Mass weighting: (dp/g) => [Pa/(m/s2)] => (Pa-s2)/m => [kg/(m-s2)][s2/m] => (kg/m2)
;---Reference: http://www.cgd.ucar.edu/cas/catalog/newbudgets/
dp = dpres_plevel_Wrap(plev, ps, ptop, 0) ; Pa; layar thickness
dpg = dp/g
dpg@long_name = "Layer Mass Weighting"
dpg@units = "kg/m2" ; dp/g, Pa/(m s-2), reduce to kg m-2
;---Moisture flux components at each pressure level
uq = u*q ; (:,:,:,:)
uq@long_name = "Zonal Moisture Flux [uq]"
uq@units = "["+u@units+"]["+q@units+"]" ; [m/s][g/kg]
copy_VarCoords(u,uq) ; (time,level,lat,lon)
vq = v*q ; (:,:,:,:)
vq@long_name = "Meridional Moisture Flux [vq]"
vq@units = "["+v@units+"]["+q@units+"]"
copy_VarCoords(v,vq) ; (time,level,lat,lon)
PRINT_RAW = True
if (PRINT_RAW) then
printVarSummary(q) ; (time,level,lat,lon); g/kg
printMinMax(q,0)
print("-----")
printVarSummary(u) ; (time,level,lat,lon); m/s
printMinMax(u,0)
print("-----")
printVarSummary(v)
printMinMax(v,0)
print("-----")
printVarSummary(ps) ; (time,lat,lon); Pa => kg/(m-s2)
printMinMax(ps,0)
print("-----")
printVarSummary(uq) ; (time,level,lat,lon); (m/s)(g/kg)
printMinMax(uq,0)
print("-----")
printVarSummary(vq)
printMinMax(vq,0)
print("-----")
printVarSummary(dp) ; (time,level,lat,lon); Pa => kg/(m-s2)
printMinMax(dp,0)
print("-----")
; examine layer thickness at selected locations
print(dp(nt,:,{40},{180})) ; mid-Pacific
print(dp(nt,:,{40},{255})) ; Boulder, CO
print("-----")
end if
;---Integrated mass weighted moisture flux components
uq_dpg = uq*dpg ; mass weighted 'uq'; [m/s][g/kg][kg/m2]=>[m/s][g/kg]
iuq = dim_sum_n(uq_dpg, 1)
iuq@long_name = "Integrated Zonal UQ [uq*dpg]"
iuq@LONG_NAME = "Sum: Mass Weighted Integrated Zonal Moisture Flux [uq*dpg]"
iuq@units = "[m/s][g/kg]"
copy_VarCoords(u(:,0,:,:), iuq); (time,lat,lon)
delete(uq_dpg)
vq_dpg = vq*dpg ; mass weighted 'vq'; [m/s][g/kg][kg/m2]=>[m/s][g/kg]
ivq = dim_sum_n(vq_dpg, 1)
ivq@long_name = "Integrated Meridional VQ [vq*dpg]"
ivq@LONG_NAME = "Sum: Mass Weighted Integrated Meridional Moisture Flux [vq*dpg]"
ivq@units = "[m/s][g/kg]"
copy_VarCoords(v(:,0,:,:), ivq); (time,lat,lon)
delete(vq_dpg)
;---Divergence of moisture flux: uv2dvF => global 'fixed' rectilinear grid
duvq = uv2dvF_Wrap(uq, vq) ; (time,level,lat,lon)
duvq@long_name = "Divergence of Moisture Flux"
duvq@units = "g/(kg-s)" ; (1/m)*[(m/s)(g/kg)] => [g/(kg-s)]
;---Mass weighted integration [sum] of the divergence of moisture flux
duvq_dpg = duvq*dpg ; [g/(kg-s)][kg/m2] => [g/(m2-s)]
iduvq = dim_sum_n(duvq_dpg, 1)
iduvq@long_name = "Integrated Mass Wgt MFC"
iduvq@LONG_NAME = "Integrated Mass Weighted Moisture Flux Convergence"
iduvq@units = "g/(m2-s)"
copy_VarCoords(u(:,0,:,:), iduvq) ; (time,lat,lon)
delete(duvq_dpg)
VIMFC = iduvq ; keep meta data
VIMFC = -VIMFC ; Note the preceding -1 [negative precedes integration]
VIMFC@long_name = "VIMFC"
;---Another way to compute Integrated divergence of moisture flux [iduvq_1]
;;IDUVQ = wgt_vertical_n(duvq, dp, 2, 1)
;;iduvq_0 = IDUVQ[0]
;;iduvq_0 = iduvq_0/g ; complete mass weighting
;;iduvq_0@long_name = "Average Mass Weighted MFC"
;;iduvq_0@LONG_NAME = "Average Mass Weighted Moisture Flux Convergence"
;;iduvq_0@units = "g/(m2-s)"
;;iduvq_1 = IDUVQ[1] ; same as iuvq_sum
;;iduvq_1 = iduvq_1/g
;;iduvq_1@long_name = "Integrated MFC"
;;iduvq_1@LONG_NAME = "Integrated Moisture Flux Convergence"
;;iduvq_1@units = "g/(m2-s)"
PRINT_RESULT = True
if (PRINT_RESULT) then
printVarSummary(iuq) ; (time,lat,lon)
printMinMax(iuq,0)
print("-----")
printVarSummary(ivq) ; (time,lat,lon)
printMinMax(ivq,0)
print("-----")
printVarSummary(duvq) ; (time,lev,lat,lon)
printMinMax(duvq,0)
print("-----")
printVarSummary(iduvq) ; (time,lat,lon)
printMinMax(iduvq,0)
print("-----")
;; printVarSummary(iduvq_0) ; (time,lat,lon)
;; printMinMax(iduvq_0,0)
;; print("-----")
;; printVarSummary(iduvq_1) ; (time,lat,lon)
;; printMinMax(iduvq_1,0)
;; print("-----")
end if
;*************************************************
; Calculate divergence: Use Wrap to include meta data
; Calculate divergent wind components; used for graphics
;*************************************************
div = uv2dvF_Wrap(u,v) ; u,v ==> divergence; (:,:,:,:)
ud = new ( dimsizes(u), typeof(u), "No_FillValue")
vd = new ( dimsizes(v), typeof(v), "No_FillValue")
dv2uvf(div,ud,vd) ; divergence ==> divergent components
copy_VarCoords(u, ud )
copy_VarCoords(u, vd )
ud@long_name = "Zonal Divergent Wind"
ud@units = u@units
vd@long_name = "Meridional Divergent Wind"
vd@units = v@units
if (PRINT_RESULT) then
printVarSummary(ud) ; (time,level,lat,lon)
printMinMax(ud,0)
print("-----")
printVarSummary(vd) ; (time,level,lat,lon)
printMinMax(vd,0)
print("-----")
end if
;*************************************************
; plot results
;*************************************************
scl5 = 1e5 ; arbitrary: used for nicer plot values
sclab5= "(10~S~-5~N~)" ; used later
SCLAB5= "(10~S~5~N~)"
scl6 = 1e6
sclab6= "(10~S~-6~N~)"
SCLAB6= "(10~S~6~N~)"
plot := new(2,graphic)
wks = gsn_open_wks("png","mfc_div") ; send graphics to PNG file
resd = True
resd@cnFillOn = True ; color
resd@cnLinesOn = False ; turn off contour lines
resd@cnLevelSelectionMode = "ManualLevels" ; set manual contour levels
resd@cnMinLevelValF = -15. ; set min contour level
resd@cnMaxLevelValF = 15. ; set max contour level
resd@cnLevelSpacingF = 1. ; set contour spacing
;resd@cnFillPalette = "cmocean_balance" ; NCL 6.5.0
resd@cnFillPalette = "ViBlGrWhYeOrRe"
resd@mpFillOn = False ; turn off map fill
resd@vcRefMagnitudeF = 3. ; make vectors larger
resd@vcRefLengthF = 0.025 ; reference vector length
resd@vcGlyphStyle = "CurlyVector" ; turn on curly vectors
resd@vcMinDistanceF = 0.010 ; thin the vectors
resd@vcRefAnnoOrthogonalPosF = -1.0 ; move ref vector up
resd@gsnLeftString = "Divergent Wind"
resd@gsnScalarContour= True ; vectors over contours
LEVP = 700
DIV = div(nt,{LEVP},:,:) ; keep meta data
DIV = DIV*scl6 ; nicer numbers
resd@tiMainString = "Divergence and Divergent Winds"
resd@gsnCenterString = LEVP+"hPa: "+date
resd@gsnRightString = sclab6+" "+div@units
dplt = gsn_csm_vector_scalar_map(wks,ud(nt,{LEVP},:,:),vd(nt,{LEVP},:,:),DIV,resd)
;--- Moisture Transport [uq, vq] at a specified pressure level
res = True ; plot mods desired
res@gsnDraw = False ; don't draw yet
res@gsnFrame = False ; don't advance frame yet
res@cnFillOn = True ; turn on color
res@cnLinesOn = False ; turn off contour lines
res@cnLineLabelsOn = False ; turn off contour lines
res@cnFillPalette = "ViBlGrWhYeOrRe" ; set White-in-Middle color map
res@lbLabelBarOn = False ; turn off individual cb's
res@mpFillOn = False ; turn off map fill
; Use a common scale
res@cnLevelSelectionMode = "ManualLevels"; manual set levels so lb consistent
res@cnMaxLevelValF = 140.0 ; max level
res@cnMinLevelValF = -res@cnMaxLevelValF ; min level
res@cnLevelSpacingF = 10.0 ; contour interval
LEVP = 700
res@gsnCenterString = LEVP+"hPa"
plot(0) = gsn_csm_contour_map(wks,uq(nt,{LEVP},:,:),res)
plot(1) = gsn_csm_contour_map(wks,vq(nt,{LEVP},:,:),res)
resP = True ; modify the panel plot
resP@gsnPanelMainString = date+": Unweighted Moisture Flux Components"
resP@gsnPanelLabelBar = True ; add common colorbar
gsn_panel(wks,plot,(/2,1/),resP) ; now draw as one plot
;--- Integrated Moisture Transport [iuq, ivq]
delete(res@gsnCenterString) ; not used for this plot
res@cnMaxLevelValF = 10.0 ; min level
res@cnMinLevelValF = -res@cnMaxLevelValF ; min level
res@cnLevelSpacingF = 0.5 ; contour interval
IUQ = iuq(nt,:,:) ; local array: keep meta data
IUQ = IUQ/scl5 ; scale for plot
res@gsnRightString = SCLAB5+" "+iuq@units
plot(0) = gsn_csm_contour_map(wks,IUQ,res)
IVQ = ivq(nt,:,:) ; local array: keep meta data
IVQ = IVQ/scl5
res@gsnRightString = SCLAB5+" "+ivq@units
plot(1) = gsn_csm_contour_map(wks,IVQ,res)
resP@gsnPanelMainString = date+": Mass Wgt. Component Moisture Flux"
gsn_panel(wks,plot,(/2,1/),resP) ; now draw as one plot
delete( [/IUQ, IVQ/] ) ; no longer needed
;---Divergence of Moisture Flux
res@cnMaxLevelValF = 100.0 ; min level
res@cnMinLevelValF = -res@cnMaxLevelValF ; min level
res@cnLevelSpacingF = 5.0 ; contour interval
LEVP = 700
DUVQ = duvq(nt,{LEVP},:,:) ; keep meta data
DUVQ = DUVQ*scl6 ; scale for plot
res@gsnCenterString = LEVP+"hPa"
res@gsnRightString = sclab6+" "+duvq@units
plot(0) = gsn_csm_contour_map(wks,DUVQ,res)
LEVP = 500
DUVQ = duvq(nt,{LEVP},:,:) ; keep meta data
DUVQ = DUVQ*scl6
res@gsnCenterString = LEVP+"hPa"
res@gsnRightString = sclab6+" "+duvq@units
plot(1) = gsn_csm_contour_map(wks,DUVQ,res)
resP@gsnPanelMainString = date+": Divergence of Moisture Flux"
gsn_panel(wks,plot,(/2,1/),resP) ; now draw as one plot
delete(DUVQ) ; no longer needed
delete([/res@gsnCenterString, res@gsnRightString/]) ; not used in next plot
;---Integrated Divergence of Moisture Flux Convergence [no scaling]
res@gsnDraw = True
res@gsnFrame = True
res@lbLabelBarOn = True
;res@cnFillPalette = "cmp_flux"
res@cnMaxLevelValF = 0.50 ; min level
res@cnMinLevelValF = -res@cnMaxLevelValF ; min level
res@cnLevelSpacingF = 0.050 ; contour interval
res@tiMainString = date+": VIMFC"
plt = gsn_csm_contour_map(wks,VIMFC(nt,:,:) ,res)
mfc_div_2.ncl
mfc_div_2.ncl: The above MFC equation can be partitioned as follows:
MFC => Moisture Flux Convergence
MFC_advect = -(u*(dq/dx)+v*(dq/dy)) ; advect moisture term
MFC_conv = -q*((du/dx)+(dv/dy) ) ; [con/div]ergence term
MFC = MFC_advect + MFC_conv
The MFC_advect can be derived using advect_variable for global rectilinear grids or advect_variable_cfd for regional rectilinear grids The MFC_conv can be derived using: uv2dvF_Wrap or uv2dvG_Wrap for global rectilinear grids or uv2dv_cfd for regional rectilinear grids. Then, multiply the derived quantity by specific humidity [q].
;*************************************************
; mfc_div_2.ncl
;
; Similar to mfc_div_1.ncl except a different approach is used.
;
; Rather tha using DIV(U*Q) directly, this script expands this into two separate components.
;
; Concepts illustrated:
; MFC = Moisture Flux Convergence
;
; MFC_advect = -(u*(dq/dx)+v*(dq/dy) ) ; advection term
; MFC_conv = -q*((du/dx)+(dv/dy) ) ; con(div)-vergence
;
; MFC = MFC_advect + MFC_convection
;
; - Plot a number of quantities
;*************************************************
;---Calculate the Horizontal Moisture Flux Convergence [MFC]
;*************************************************
;---High frequency source data: hourly/3hr/6hr/12hr/daily .... NOT monthly values
;---References:
;---http://www.cgd.ucar.edu/cas/catalog/newbudgets/
;---http://tornado.sfsu.edu/geosciences/classes/e260/AtmosphericRivers/Moisture%20Flux.pdf
;---https://www.spc.noaa.gov/publications/banacos/mfc-sls.pdf
;===================================================================
; Data Source: ESRL Physical Sciences Division
; https://www.esrl.noaa.gov/psd/data/gridded/data.ncep.reanalysis.html
; NCEP Reanalysis data provided by the NOAA/OAR/ESRL PSD, Boulder, Colorado, USA,
; from their Web site at https://www.esrl.noaa.gov/psd/
;===================================================================
ptop = 300 ; 'shum' upper level
ptop@units = "hPa"
g = 9.80665 ; m/s2
date = 20080715 ; NH summer
;---ESRL: CDC data
diri = "./"
filq = "shum.2008.nc" ; daily data for current year [366 days]
filu = "uwnd.2008.nc"
filv = "vwnd.2008.nc"
filps= "pres.sfc.2008.nc"
pthu = diri+filu
pthv = diri+filv
pthq = diri+filq
pthps= diri+filps
fu = addfile(pthu ,"r")
fv = addfile(pthv ,"r")
fq = addfile(pthq ,"r")
fps = addfile(pthps,"r")
;---Time
ymd = cd_calendar(fu->time, -2) ; ymd[*]: human readable
nt = ind(ymd.eq.date) ; date for plotting and testing
TEST = True
if (.not.TEST) then ; all times
u = fu->uwnd(:,{1000:ptop},:,:) ; m/s, (time,level,lat,lon)
v = fv->vwnd(:,{1000:ptop},:,:)
q = fq->shum ; [kg/kg], 1000-300 levels only
ps = fps->pres ; Pa=>[kg/(m-s2)], (time,lat,lon)
else ; one time step; keep time dimension [ nt:nt: ]
u = fu->uwnd(nt:nt,{1000:ptop},:,:); m/s, (time,level,lat,lon)
v = fv->vwnd(nt:nt,{1000:ptop},:,:)
q = fq->shum(nt:nt,:,:,:) ; [kg/kg], 1000-300 levels only
ps = fps->pres(nt:nt,:,:) ; Pa=>[kg/(m-s2)], (time,lat,lon)
nt = 0 ; only one time step
end if
;---Vertical levels
ptop = ptop*100
ptop@units = "Pa"
plev = q&level ; hPa
plev = plev*100 ; [100000,...,30000] Pa [kg/(m-s2)]
plev@units = "Pa"
;---Change [kg/kg] to [g/kg]; not necessary: but common units for q
q = q*1000
q@units = "g/kg"
;---Divergence function [used later] requires S->N grid order
u = u(:,:,::-1,:)
v = v(:,:,::-1,:)
q = q(:,:,::-1,:)
ps =ps(:, ::-1,:)
;---Layer thickness: ; Pa=>[kg/(m-s2)], (time,level,lat,lon)
;---Mass weighting: (dp/g) => [Pa/(m/s2)] => (Pa-s2)/m => [kg/(m-s2)][s2/m] => (kg/m2)
;---Reference: http://www.cgd.ucar.edu/cas/catalog/newbudgets/
dp = dpres_plevel_Wrap(plev, ps, ptop, 0) ; Pa; layar thickness
dpg = dp/g
dpg@long_name = "Layer Mass Weighting"
dpg@units = "kg/m2" ; dp/g, Pa/(m s-2), reduce to kg m-2
;************************************************
; Calculate the MFC_advection term
; MFC_advect = -(u*(dq/dx)+v*(dq/dy) )
; Internally, gradients are calculated via spherical harmonics
;*************************************************
long_name = "MFC_advection"
units = "g/(kg-s)" ; (m/s)*(g/kg)*(1/m) => (m/s)*(g/kg-m) => g/(kg-s)
gridType = 1 ; global fixed grid ordered S->N
opt_adv = 0 ; return only the advected variable; no gradients
mfc_adv = advect_variable(u,v,q, gridType, long_name, units, opt_adv)
mfc_adv = -mfc_adv
printVarSummary(mfc_adv)
printMinMax(mfc_adv, 0)
print("--------")
;************************************************
; Calculate the MFC_convergence term
; MFC_conv = -q*((du/dx)+(dv/dy) ) ; con(div)-vergence
;*************************************************
duv = uv2dvF_Wrap(u, v) ; (1/m)(m/s) => (1/s) ; (time,level,lat,lon)
mfc_con = -q*duv
mfc_con@long_name = "MFC_convergence"
mfc_con@units = "g/(kg-s)" ; (g/kg)(1/s) => g/(kg-s)
copy_VarCoords(duv,mfc_con)
delete(duv)
;************************************************
; Calculate the total MFC
;*************************************************
mfc = mfc_adv + mfc_con
mfc@long_name = "Moisture Flux Convergence"
mfc@units = "g/(kg-s)" ; (g/kg)(1/s) => g/(kg-s)
PRINT_RAW = True
if (PRINT_RAW) then
printVarSummary(mfc_adv) ; (time,level,lat,lon)
printMinMax(mfc_adv,0)
printVarSummary(mfc_con)
printMinMax(mfc_con,0)
print("-----")
printVarSummary(mfc)
printMinMax(mfc,0)
print("-----")
printVarSummary(ps) ; (time,lat,lon); Pa => kg/(m-s2)
printMinMax(ps,0)
print("-----")
printVarSummary(dp) ; (time,level,lat,lon); Pa => kg/(m-s2)
printMinMax(dp,0)
print("-----")
; examine layer thickness at selected locations
print(dp(nt,:,{40},{180})) ; mid-Pacific
print(dp(nt,:,{40},{255})) ; Boulder, CO
print("-----")
end if
;---Integrated mass weighted moisture flux components
mfc_adv_dpg = mfc_adv*dpg ; mass weighted 'uq'; [m/s][g/kg][kg/m2]=>[m/s][g/kg]
imfc_adv = dim_sum_n(mfc_adv_dpg, 1)
imfc_adv@long_name = "Integrated Mass Flux Advection"
imfc_adv@LONG_NAME = "Sum: Mass Weighted Integrated Mass Flux Advection: mfc_adv*dpg"
imfc_adv@units = "[m/s][g/kg]"
copy_VarCoords(u(:,0,:,:), imfc_adv); (time,lat,lon)
delete(mfc_adv_dpg)
mfc_con_dpg = mfc_con*dpg ; mass weighted 'mfc_con'; [m/s][g/kg][kg/m2]=>[m/s][g/kg]
imfc_con = dim_sum_n(mfc_con_dpg, 1)
imfc_con@long_name = "Integrated Mass Flux Convergence"
imfc_con@LONG_NAME = "Sum: Mass Weighted Integrated Mass Flux Convergence [mfc_con*dpg]"
imfc_con@units = "[m/s][g/kg]"
copy_VarCoords(v(:,0,:,:), imfc_con); (time,lat,lon)
delete(mfc_con_dpg)
VIMFC = imfc_adv + imfc_con
VIMFC@long_name = "VIMFC"
VIMFC@LONG_NAME = "VIMFC: [imfc_adv+imfc_con]"
copy_VarCoords(q(:,0,:,:),VIMFC) ; (time,lat,lon)
PRINT_RESULT = True
if (PRINT_RESULT) then
printVarSummary(imfc_adv) ; (time,lat,lon)
printMinMax(imfc_adv,0)
print("-----")
printVarSummary(imfc_con) ; (time,lat,lon)
printMinMax(imfc_con,0)
print("-----")
printVarSummary(VIMFC) ; (time,lat,lon)
printMinMax(VIMFC,0)
print("-----")
end if
;*************************************************
; plot results
;*************************************************
scl5 = 1e5 ; arbitrary: used for nicer plot values
sclab5= "(10~S~-5~N~)" ; used later
SCLAB5= "(10~S~5~N~)"
scl6 = 1e6
sclab6= "(10~S~-6~N~)"
SCLAB6= "(10~S~6~N~)"
plot := new(2,graphic)
wks = gsn_open_wks("png","mfc_div_2") ; send graphics to PNG file
;--- mfc_adv and mfc_con at a specified pressure level
res = True ; plot mods desired
res@gsnDraw = False ; don't draw yet
res@gsnFrame = False ; don't advance frame yet
res@cnFillOn = True ; turn on color
res@cnLinesOn = False ; turn off contour lines
res@cnLineLabelsOn = False ; turn off contour lines
res@cnFillPalette = "ViBlGrWhYeOrRe" ; set White-in-Middle color map
res@mpFillOn = False ; turn off map fill
res@lbLabelBarOn = False ; turn off individual cb's
; Use a common scale
res@cnLevelSelectionMode = "ManualLevels"; manual set levels so lb consistent
res@cnMaxLevelValF = 12.0 ; max level
res@cnMinLevelValF = -res@cnMaxLevelValF ; min level
res@cnLevelSpacingF = 0.5 ; contour interval
LEVP = 700
res@gsnCenterString = LEVP+"hPa"
MFC_ADV = mfc_adv(nt,{LEVP},:,:) ; keep meta data
MFC_ADV = MFC_ADV*scl5
res@gsnRightString = sclab5+" "+mfc_adv@units
plot(0) = gsn_csm_contour_map(wks,MFC_ADV,res)
MFC_CON = mfc_con(nt,{LEVP},:,:)
MFC_CON = MFC_CON*scl5
res@gsnRightString = sclab5+" "+mfc_con@units
plot(1) = gsn_csm_contour_map(wks,MFC_CON,res)
resP = True ; modify the panel plot
resP@gsnPanelMainString = date+": Unweighted MFC_ADV, MFC_CON"
resP@gsnPanelLabelBar = True ; add common colorbar
gsn_panel(wks,plot,(/2,1/),resP) ; now draw as one plot
;--- Integrated Moisture Transport [iuq, ivq]
delete([/res@gsnRightString, res@gsnCenterString/]) ; not used for this plot
res@cnMaxLevelValF = 0.50 ; min level
res@cnMinLevelValF = -res@cnMaxLevelValF ; min level
res@cnLevelSpacingF = 0.05 ; contour interval
IMFC_ADV = imfc_adv(nt,:,:) ; local array: keep meta data
plot(0) = gsn_csm_contour_map(wks,IMFC_ADV,res)
IMFC_CON = imfc_con(nt,:,:) ; local array: keep meta data
plot(1) = gsn_csm_contour_map(wks,IMFC_CON,res)
resP@gsnPanelMainString = date+": Integrated Moisture Flux: Advect, Convergence"
gsn_panel(wks,plot,(/2,1/),resP) ; now draw as one plot
delete( [/IMFC_ADV, IMFC_CON/] ) ; no longer needed
res@lbLabelBarOn = True
res@gsnDraw = True
res@gsnFrame= True
;---Integrated Divergence of Moisture Flux Convergence [no scaling]
;res@cnFillPalette = "cmp_flux"
res@cnLevelSelectionMode = "ManualLevels"; manual set levels so lb consistent
res@cnMaxLevelValF = 0.50 ; min level
res@cnMinLevelValF = -res@cnMaxLevelValF ; min level
res@cnLevelSpacingF = 0.050 ; contour interval
res@tiMainString = date+": VIMFC: [IMFC_ADV+IMFC_CON]"
plt = gsn_csm_contour_map(wks,VIMFC(nt,:,:) ,res)本文参与 腾讯云自媒体同步曝光计划，分享自微信公众号。
原始发表：2020-12-17，如有侵权请联系 cloudcommunity@tencent.com 删除
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