spuv2dz.f File Reference

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Functions/Subroutines
subroutine	spuv2dz (I, M, ENN1, ELONN1, EON, EONTOP, U, V, UTOP, VTOP, D, Z)
	Computes the divergence and vorticity from wind components in spectral space. More...

Detailed Description

Compute divergence and vorticity from winds

Author

IREDELL

Date

92-10-31

Definition in file spuv2dz.f.

Function/Subroutine Documentation

spuv2dz()

subroutine spuv2dz	(		I,
			M,
		real, dimension((m+1)*((i+1)*m+2)/2)	ENN1,
		real, dimension((m+1)*((i+1)*m+2)/2)	ELONN1,
		real, dimension((m+1)*((i+1)*m+2)/2)	EON,
		real, dimension(m+1)	EONTOP,
		real, dimension((m+1)*((i+1)*m+2))	U,
		real, dimension((m+1)*((i+1)*m+2))	V,
		real, dimension(2*(m+1))	UTOP,
		real, dimension(2*(m+1))	VTOP,
		real, dimension((m+1)*((i+1)*m+2))	D,
		real, dimension((m+1)*((i+1)*m+2))	Z
	)

Computes the divergence and vorticity from wind components in spectral space.

SUBPROGRAM SPEPS SHOULD BE CALLED ALREADY. IF L IS THE ZONAL WAVENUMBER, N IS THE TOTAL WAVENUMBER, EPS(L,N)=SQRT((N**2-L**2)/(4*N**2-1)) AND A IS EARTH RADIUS, THEN THE DIVERGENCE D IS COMPUTED AS

 D(L,N)=I*L*A*U(L,N)
 +EPS(L,N+1)*N*A*V(L,N+1)-EPS(L,N)*(N+1)*A*V(L,N-1)
 

AND THE VORTICITY Z IS COMPUTED AS

 Z(L,N)=I*L*A*V(L,N)
 -EPS(L,N+1)*N*A*U(L,N+1)+EPS(L,N)*(N+1)*A*U(L,N-1)
 

WHERE U IS THE ZONAL WIND AND V IS THE MERIDIONAL WIND. U AND V ARE WEIGHTED BY THE SECANT OF LATITUDE. EXTRA TERMS ARE USED OVER TOP OF THE SPECTRAL DOMAIN. ADVANTAGE IS TAKEN OF THE FACT THAT EPS(L,L)=0 IN ORDER TO VECTORIZE OVER THE ENTIRE SPECTRAL DOMAIN.

Parameters

I	- INTEGER SPECTRAL DOMAIN SHAPE (0 FOR TRIANGULAR, 1 FOR RHOMBOIDAL)
M	- INTEGER SPECTRAL TRUNCATION
ENN1	- REAL ((M+1)*((I+1)*M+2)/2) N*(N+1)/A**2
ELONN1	- REAL ((M+1)*((I+1)*M+2)/2) L/(N*(N+1))*A
EON	- REAL ((M+1)*((I+1)*M+2)/2) EPSILON/N*A
EONTOP	- REAL (M+1) EPSILON/N*A OVER TOP
U	- REAL ((M+1)*((I+1)*M+2)) ZONAL WIND (OVER COSLAT)
V	- REAL ((M+1)*((I+1)*M+2)) MERID WIND (OVER COSLAT)
UTOP	- REAL (2*(M+1)) ZONAL WIND (OVER COSLAT) OVER TOP
VTOP	- REAL (2*(M+1)) MERID WIND (OVER COSLAT) OVER TOP
D	- REAL ((M+1)*((I+1)*M+2)) DIVERGENCE
Z	- REAL ((M+1)*((I+1)*M+2)) VORTICITY

Definition at line 41 of file spuv2dz.f.