[ncl-talk] Eady _growth_rate
Dennis Shea
shea at ucar.edu
Fri Aug 17 10:22:14 MDT 2018
Eady's seminal paper was written in 1949. It (the '*Eady Model*
<https://en.wikipedia.org/wiki/Eady_Model>' ) is based on many
assumptions. The scale analysis that allowed the simplification of the
equations was based on a mid-latitude assumption. Hence, calculated values
"near" the equator may/may-not be useful. As they say: Beauty, is in the
eyes of the beholder.
FYI: the following was developed in 2012 about 5 years before NCL's
function was released [2/1017: NCL 6.4.0]
*https://k3.cicsnc.org/carl/carl-ncl-tools/blob/master/ncep/eady.ncl
<https://k3.cicsnc.org/carl/carl-ncl-tools/blob/master/ncep/eady.ncl>*
On Fri, Aug 17, 2018 at 9:33 AM, George Vandenberghe - NOAA Affiliate <
george.vandenberghe at noaa.gov> wrote:
> There was a tangential thread about the relevance of Eady Growth Rates in
> a tropical cyclone environment. The function can give you
> a number but is it realistic with the approximations made for
> quasi-geostrophic baroclinic theory?
>
> Apart from that though the problem is very relevant when considering a
> tropical cyclone as a source of a perturbation
> in a baroclinic zone and that situation is common to general with
> recurving tropical cyclones.
>
>
> On Fri, Aug 17, 2018 at 10:28 AM, Dennis Shea <shea at ucar.edu> wrote:
>
>>
>> printVarSummary(T41) ; ; [Time|12]x[ilev |* 26*] x [lat |
>> 96] x [lon | 144]
>> printVarSummary(T411) ; ; [Time|12]x[ilev | *26*] x [lat |
>> 96] x [lon | 144]
>> printVarSummary(T412) ; ; [Time|12]x[ilev | *27*] x [lat |
>> 96] x [lon | 144]
>>
>> Variable T412 is the issue. The 'ilev' dimension is different.
>>
>> You must interpolate it to the same dimensions as T41, T411
>>
>> pressure: int2p_n
>> <http://www.ncl.ucar.edu/Document/Functions/Built-in/int2p_n.shtml> or,
>> better, *int2p_n_Wrap
>> <http://www.ncl.ucar.edu/Document/Functions/Contributed/int2p_n_Wrap.shtml>*
>> ====
>>
>> hybrid vertical coordinates: vinth2p
>> <http://www.ncl.ucar.edu/Document/Functions/Built-in/vinth2p.shtml>
>>
>> On Fri, Aug 17, 2018 at 8:07 AM, Sri Nandini <snandini at marum.de> wrote:
>>
>>> Hello
>>>
>>> I am trying to plot the eady growth rate as a measure of baroclinic
>>> instability. I cannot due to:
>>> fatal:conform: The array to be conformed must have the same number of
>>> dimensions as indicated by the length of the last argument
>>> I cannot conform the latitude to same dimensions as the th variable.
>>>
>>> Below is my script, would be grateful for any suggestions.
>>>
>>>
>>> load "lat_lon_masked_lambert.ncl"
>>>
>>> ; ==============================================================
>>> ; Open the file: Read only the user specified period first observations
>>> then model
>>> ; ==============================================================
>>> f= addfile("SLP_PHIS_Z3_PI.nc", "r") ;
>>> T41 = f->Z3(:,:,:,:)
>>>
>>> printVarSummary(T41) ; ;
>>> [Time|12]x[ilev | 26] x [lat | 96] x [lon | 144]
>>> T41 at _FillValue = -9.96921e+36
>>>
>>> ;==============================================================
>>>
>>> f1= addfile("totalwinds_PI.nc", "r") ;
>>> T411 = f1->U(:,:,:,:)
>>>
>>> printVarSummary(T411) ; ;
>>> [Time|12]x[ilev | 26] x [lat | 96] x [lon | 144]
>>> T411 at _FillValue = -9.96921e+36
>>>
>>>
>>> ;==============================================================
>>> f2= addfile("th_PI.nc", "r") ;
>>> T412 = f2->TH(:,:,:,:)
>>>
>>> printVarSummary(T412) ; ;
>>> [Time|12]x[ilev | 27] x [lat | 96] x [lon | 144]
>>> T412 at _FillValue = -9.96921e+36
>>>
>>> ;==============================================================
>>>
>>> ; Read latitudes
>>> ; The 'eady_growth_rate' function requires that 'lat' and 'th' agree
>>> ; Use 'conform' the propogate the lat values
>>> ;==============================================================
>>>
>>> xlat = f->lat ; [lat | 96]
>>> printVarSummary(xlat)
>>>
>>> XLAT = conform(T412, xlat, (/0,2,3/)) ; problem here
>>> printVarSummary(XLAT)
>>>
>>> egr = eady_growth_rate(aveX2, aveX1, aveX, XLAT, 0, 1)
>>> printVarSummary(egr)
>>> printMinMax(egr, 0)
>>>
>>> ;==============================================================
>>> wks = gsn_open_wks("pdf","Eady") ; send graphics to PNG
>>> file
>>>
>>> ;---Set some basic plot options
>>>
>>> res = True
>>> res at gsnMaximize = True ; maximize plot in frame
>>> res at gsnAddCyclic = False
>>>
>>> res at cnFillOn = True
>>> res at cnLinesOn = False
>>> ;res at cnFillMode = "RasterFill" ; slow here
>>> res at cnFillMode = "CellFill" ; faster
>>>
>>>
>>> minlat = 25. ; min lat to mask
>>> maxlat = 80. ; max lat to mask
>>> minlon = -10. ; min lon to mask
>>> maxlon = 110. ; max lon to mask
>>> res at mpProjection = "LambertConformal" ; choose projection
>>>
>>> ;---masked plot
>>> res at gsnAddCyclic = True ; regional plot
>>>
>>> res at mpMinLatF = minlat ; min lat to mask
>>> res at mpMaxLatF = maxlat ; max lat to mask
>>> res at mpMinLonF = minlon ; min lon to mask
>>> res at mpMaxLonF = maxlon ; max lon to mask
>>>
>>> res at gsnMaskLambertConformal = True ; turn on lc masking
>>>
>>> ; specify a level or levels ... within boundary layer
>>>
>>> klStrt = 5
>>> klLast = 5
>>> nt = 0
>>>
>>> ;--- Eady growth rate (1/day)
>>>
>>> egr = egr*86400
>>> egr at units = "1/day"
>>>
>>> res at cnFillPalette = "precip2_17lev"
>>> res at cnLevelSelectionMode = "ManualLevels" ; set manual contour
>>> levels
>>> res at cnMinLevelValF = 0.5 ; set min contour level
>>> res at cnMaxLevelValF = 4.0 ; set max contour level
>>> res at cnLevelSpacingF = 0.25 ; set contour spacing
>>>
>>> do kl=klStrt,klLast
>>> res at gsnCenterString = "znu="+znu(nt,kl)
>>> res at gsnRightString = egr at units
>>> contour = gsn_csm_contour_map(wks, egr(nt,kl,:,:),res)
>>> end do
>>>
>>>
>>>
>>>
>>>
>>>
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>>
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