Module: NumRu::GAnalysis::Planet

Defined in:
lib/numru/ganalysis/planet.rb

Overview

Library for spherical planets (thin spherical shell; default: Earth)

ASSUMPTIONS

  • longitude is assumed to increase in the eastward direction.

  • latitude is assumed to increase in the northward direction, and it is zero at the equator.

Constant Summary collapse

Earth =

< Pre-defined planets >

"Earth"
@@lonbc =

< Class variables regarding lon & lat >

GPhys::Derivative::CYCLIC_OR_LINEAR
@@lam =

@@latbc = GPhys::Derivative::LINEAR_EXT # this should be always fine

nil
@@phi =

lambda (lon in radian) obtaiend lately (see get_lambda_phi)

nil

Class Method Summary collapse

Class Method Details

.absvor_s(u, v) ⇒ Object 



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# File 'lib/numru/ganalysis/planet.rb', line 105

def absvor_s(u,v)
  avor = vor_s(u,v) + @@phi.sin * (2*@@Ome)
  avor.long_name = "Absolute Vorticity"
  avor.name = "avor"
  avor
end

.ave_s(s) ⇒ Object

horizontal averaging considering the spherical geometry



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# File 'lib/numru/ganalysis/planet.rb', line 66

def ave_s(s)
  lam, phi, lond, latd  = get_lambda_phi(s)
  xmean = s.mean(lond)
  cos_phi = phi.cos

  lond,latd = find_lon_lat_dims(xmean)  # find latd again
  wgt = cos_phi / cos_phi.sum
  (xmean * wgt).sum(latd)
end

.div_s(u, v) ⇒ Object 



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# File 'lib/numru/ganalysis/planet.rb', line 87

def div_s(u,v)
  lam, phi, lond, latd  = get_lambda_phi(u)
  cos_phi = phi.cos
  du_dlam = u.cderiv(lond,@@lonbc,lam)
  dvc_dphi  = (v*cos_phi).cderiv(latd,latbc(phi),phi)
  rot = (du_dlam + dvc_dphi) / (@@R*cos_phi)
  rot.long_name = "div(#{u.name},#{v.name})"
  rot.name = "div"
  rot
end

.find_lon_lat_dims(gp, err_raise = false) ⇒ Object

Find longitude and latitude coordinates.

ARGUMENTS

  • gp : GPhys to inspect

  • err_raise (OPTIONAL; default:false) : if true, exception is raised if longitude or latitude coordinate is not found.

SEARCH CRITERIA (1) Find coord having units “degrees_east” (lon) or 

"degrees_north" (lat)

(2) Investigate coordinate name matches (to find a lonitude coord, 

/longitude/i for long_name or standard_name, or /^lon/ for name)
and match units compatible with "degrees".

RETURN VALUE

  • lond,latd

    • lond: dimension number of longitude (0,1,..) if found / nil if not found

    • latd: dimension number of latitude (0,1,..) if found / nil if not found



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# File 'lib/numru/ganalysis/planet.rb', line 221

def find_lon_lat_dims(gp, err_raise=false)
  lond = nil
  latd = nil
  (0...gp.rank).each do |dim|
    crd = gp.coord(dim)
    if /^degrees?_east$/i =~ crd.get_att("units")
      lond = dim
      break
    elsif ( ( /longitude/i =~ crd.long_name || 
              /^lon/i =~ crd.name ||
              (nm=crd.get_att("standard_name") && /longitude/i =~ nm ) &&
              (crd.units =~ Units["degrees_east"]) ) )
      lond = dim
      break
    end
  end
  (0...gp.rank).each do |dim|
    next if dim == lond
    crd = gp.coord(dim)
    if /^degrees?_north$/i =~ crd.get_att("units")
      latd = dim
      break
    elsif ( ( /latitude/i =~ crd.long_name || 
              /^lat/i =~ crd.name ||
              (nm=crd.get_att("standard_name") && /latitude/i =~ nm ) &&
              (crd.units =~ Units["degrees_north"]) ) )
      latd = dim
      break
    end
  end
  if err_raise
    raise("Longitude dimension was not found") if !lond
    raise("Latitude dimension was not found") if !latd
  end
  [lond,latd]
end

.get_lambda_phi(gp, err_raise = true) ⇒ Object

Find longitude and latitude coordinates and convert into radian.

RETURN VALUE

  • lam, phi, lond, latd

    • lam (GPhys): longitude in radian (lambda). (nil if not found && !err_raise)

    • phi (GPhys): latitude in radian (lambda). (nil if not found && !err_raise)

    • lond : Interger to show that longitude is the lon-th dim if found; (nil if not found && !err_raise)

    • latd : Interger to show that latitude is the lat-th dim iffound; (nil if not found && !err_raise)



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# File 'lib/numru/ganalysis/planet.rb', line 188

def get_lambda_phi(gp, err_raise=true)
  lond, latd = find_lon_lat_dims(gp, err_raise)
  lam = lond && gp.axis(lond).to_gphys.convert_units("rad") # lon in rad
  lam.units = "" if lond                            # treat as non-dim
  phi = latd && gp.axis(latd).to_gphys.convert_units("rad") # lat in rad
  phi.units = "" if latd                            # treat as non-dim
  @@lam = lam
  @@phi = phi
  [lam, phi, lond, latd]
end

.grad_s(s) ⇒ Object 



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# File 'lib/numru/ganalysis/planet.rb', line 112

def grad_s(s)
  lam, phi, lond, latd  = get_lambda_phi(s)
  cos_phi = phi.cos
  xs = s.cderiv(lond,@@lonbc,lam) / (@@R*cos_phi)
  ys = s.cderiv(latd,latbc(phi),phi) / @@R
  xs.long_name = "xgrad(#{s.name})"
  xs.name = "xgrad"
  ys.long_name = "ygrad(#{s.name})"
  ys.name = "ygrad"
  [xs,ys]
end

.grad_sx(s) ⇒ Object 



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# File 'lib/numru/ganalysis/planet.rb', line 124

def grad_sx(s)
  lam, phi, lond, latd  = get_lambda_phi(s)
  cos_phi = phi.cos
  xs = s.cderiv(lond,@@lonbc,lam) / (@@R*cos_phi)
  xs.long_name = "xgrad(#{s.name})"
  xs.name = "xgrad"
  xs
end

.grad_sy(s) ⇒ Object 



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# File 'lib/numru/ganalysis/planet.rb', line 133

def grad_sy(s)
  lam, phi, lond, latd  = get_lambda_phi(s)
  cos_phi = phi.cos
  ys = s.cderiv(latd,latbc(phi),phi) / @@R
  ys.long_name = "ygrad(#{s.name})"
  ys.name = "ygrad"
  ys
end

.grad_sy_cosphifact(s, cosphi_exponent) ⇒ Object 



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# File 'lib/numru/ganalysis/planet.rb', line 142

def grad_sy_cosphifact(s,cosphi_exponent)
  lam, phi, lond, latd  = get_lambda_phi(s)
  cos_phi = phi.cos
  cos_phi_factor = cos_phi**cosphi_exponent
  ys = (s*cos_phi_factor).cderiv(latd,latbc(phi),phi)/cos_phi_factor / @@R
  ys.long_name = "ygrad(#{s.name})"
  ys.name = "ygrad"
  ys
end

.init(planet) ⇒ Object 



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# File 'lib/numru/ganalysis/planet.rb', line 19

def init(planet)
  case planet
  when Earth
    @@R = UNumeric[6.37e6, "m"]
    @@Ome = UNumeric[2*Math::PI/8.64e4,"s-1"]
  else
    raise "Unsupported predefined planet: #{planet}."
  end
end

.latbc(phi) ⇒ Object

< Differentian at the planets’s near surface. With suffix “_s” >



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# File 'lib/numru/ganalysis/planet.rb', line 48

def latbc(phi)
=begin
  # not so good
  pi2 = Math::PI/2
  eps = 0.1
  xs = phi[0..1].val 
  xe = phi[-2..-1].val
  if (pi2-xs[0].abs) / (xs[0]-xs[1]).abs < eps and
     (pi2-xe[-1].abs) / (xe[-1]-xe[-2]).abs < eps 
    GPhys::Derivative::MIRROR_B
  else
    GPhys::Derivative::LINEAR_EXT
  end
=end
  GPhys::Derivative::LINEAR_EXT
end

.omega ⇒ Object 



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# File 'lib/numru/ganalysis/planet.rb', line 36

def omega; @@Ome; end

.omega=(o) ⇒ Object 



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# File 'lib/numru/ganalysis/planet.rb', line 34

def omega=(o);  @@Ome = o; end

.radius ⇒ Object 



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# File 'lib/numru/ganalysis/planet.rb', line 35

def radius; @@R; end

.radius=(r) ⇒ Object

< Adjustable planetary settings >



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# File 'lib/numru/ganalysis/planet.rb', line 33

def radius=(r); @@R = r; end

.rot_s(u, v) ⇒ Object 



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# File 'lib/numru/ganalysis/planet.rb', line 76

def rot_s(u,v)
  lam, phi, lond, latd  = get_lambda_phi(u)
  cos_phi = phi.cos
  dv_dlam = v.cderiv(lond,@@lonbc,lam)
  duc_dphi  = (u*cos_phi).cderiv(latd,latbc(phi),phi)
  rot = (dv_dlam - duc_dphi) / (@@R*cos_phi)
  rot.long_name = "rot(#{u.name},#{v.name})"
  rot.name = "rot"
  rot
end

.vor_s(u, v) ⇒ Object 



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# File 'lib/numru/ganalysis/planet.rb', line 98

def vor_s(u,v)
  vor = rot_s(u,v)
  vor.long_name = "Relative Vorticity"
  vor.name = "vor"
  vor
end

.weight_cosphi(s, cos_exp, r_exp) ⇒ Object 



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# File 'lib/numru/ganalysis/planet.rb', line 159

def weight_cosphi(s, cos_exp, r_exp)
  lam, phi, lond, latd  = get_lambda_phi(s)
  cos_phi = phi.cos
  ys = s * (cos_phi**cos_exp * @@R**r_exp)
  ys
end

.weight_sinphi(s, sin_exp, r_exp) ⇒ Object 



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# File 'lib/numru/ganalysis/planet.rb', line 166

def weight_sinphi(s, sin_exp, r_exp)
  lam, phi, lond, latd  = get_lambda_phi(s)
  sin_phi = phi.sin
  ys = s * (sin_phi**sin_exp * @@R**r_exp)
  ys
end

.weight_tanphi(s, tan_exp, r_exp) ⇒ Object 



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# File 'lib/numru/ganalysis/planet.rb', line 152

def weight_tanphi(s, tan_exp, r_exp)
  lam, phi, lond, latd  = get_lambda_phi(s)
  tan_phi = phi.tan
  ys = s * (tan_phi**tan_exp * @@R**r_exp)
  ys
end