CAPE_CIN {aiRthermo}

Calculation of CAPE and CIN

Description

Taking into account the data obtained in a radiosonde, and after defining the initial values of the parcel, this function calculates the values of CAPE and CIN for the sounding.

Usage

CAPE_CIN(Ps, Ts, ws, deltaP = 5, P0 = NA, T0 = NA, w0 = NA, PlowTop = NA, 
precoolType = "none", doLog = 0, getLiftedBack = FALSE, upToTop = TRUE, 
checkBuoyancy = 0)

Arguments

Ps

Pressures (Pa) defining the sounding.

Ts

Temperatures (K) defining the sounding.

ws

Mixing ratios (kg/kg) defining the sounding.

deltaP

The width (Pa) of the layers used in the calculation of the numerical solution for the vertical evolution. A default value of 5 Pa is used. It must be positive.

P0

The initial pressure (Pa) for the parcel that is lifted (may be the lowest level of the sounding). Missing value is used by default.

T0

The initial temperature (K) of the parcel being lifted. Missing value is used by default.

w0

The initial mixing ratio (kg/kg) of the parcel being lifted.

PlowTop

If some layers must be averaged in the bottom of the sounding this argument provides the pressure (Pa) at the top of the layer that must be averaged in the bottom of the sounding. NA is used by default.

precoolType

If requested, an adiabatic or an isobaric precooling of the initial parcel is performed. "none" is used by default, but "adiabatic" and "isobaric" are also accepted.

doLog

Use logarithmic vertical interpolation between sounding levels if doLog=1. The default value is doLog=0.

getLiftedBack

TRUE/FALSE requests that the evolution of the lifted particle until the top level of the soundig is returned as a set of vectors for P, T and w (fields Pl, Tl and wl respectively). FALSE is used by default.

upToTop

TRUE(FALSE) requests that the lifted particle continues(stops) after the first crossing with the ambient sounding (EL) (until the sounding finishes). If TRUE, remaining negative areas above are accumulated into CIN only if the parcel becomes buoyant again in upper levels depending on the setting of checkBuoyancy. TRUE is used by default.

checkBuoyancy

If checkBuoyancy is TRUE, the computation of CAPE and CIN proceed to the top of the sounding if upToTop is TRUE if CAPE is larger than CIN while the parcel passes non-buoyant regions. The default value is FALSE.

Details

CAPE and CIN (J/kg) are calculated from a sounding given by 1D arrays for pressure Ps (Pa), for temperature Ts (K) and for mixing ratio ws (kg/kg).

If P_0/T_0/w_0 are provided, no low vertical averaging is done and these values are used as initial points for the parcel. Missing value is used by default for these arguments.

This function returns some error codes in field outCode in the return value if the computation of CAPE and CIN failed.

Value

Returns:

airStart

The real starting variable of the air parcel. It is a vector with 6 elements: P (Pa), Temp (K), w (kg/kg), theta (K), Tvirtual (K) and wsat (kg/kg). The values are computed depending on the input arguments.

cape

CAPE index (J/kg).

cin

CIN index (J/kg) as a negative number.

apLCL

Variables of the air parcel at the Lifting Condensation Level (LCL). It is returned as a vector with 6 elements: P (Pa), Temp (K), w (kg/kg), theta (K), virtualT (K) and wsat (kg/kg).

apLFC

Variables of the Level of Free Convection (LFC). If LFC is found, it is returned as a vector with six elements: P (Pa), Temp (K), w (kg/kg), theta (K), virtualT (K) and wsat (kg/kg).

apEL

End Level (EL). If EL is found, it is returned as a vector with six elements: P (Pa), Temp (K), w (kg/kg), theta (K), virtualT (K) and wsat (kg/kg).

gotLCL

TRUE/FALSE whether the LCL has been found or not.

gotLFC

TRUE/FALSE whether the LFC has been found or not.

gotEL

TRUE/FALSE whether the EL has been found or not.

Pl

Pressure (Pa) at every step of the lifted particle during its evolution. If requested by using getLiftedBack==TRUE, every step until the end of the radiosonde is returned.

Tl

Temp (K) at every step of the lifted particle during its evolution. If requested by using getLiftedBack==TRUE, every step until the end of the radiosonde is returned.

wl

Mixing-ratio of the lifted particle during its evolution. If requested by using getLiftedBack==TRUE, every step until the end of the radiosonde is returned.

Olifted

Number of elements in Pl/Tl/wl.

upToTop

Process the whole sounding even after finding the first "EL level".

outCode

The error code returned by the C routine that computes CAPE/CIN. If 0, everything has been OK!

Examples

data(RadiosondeA)
aPs<-RadiosondeA[,1]*100
aTs<-C2K(RadiosondeA[,3])
aws<-RadiosondeA[,6]/1000
capeCin<-CAPE_CIN(PlowTop=98000,precoolType="adiabatic",
                  Ps=aPs,Ts=aTs,ws=aws,doLog=0,deltaP=5,
                  getLiftedBack=TRUE,upToTop=TRUE)
print(min(capeCin$Tl))

pdf("stuve.pdf")
stuveA<-stuve_diagram(Pres = aPs/100,Temp=aTs-273.15)
lines(capeCin$Tl-273.15,capeCin$Pl/100,col="red",lwd=2)
dev.off()