;****************************************************
; xy_28.ncl
;
; Concepts illustrated:
;   - Drawing a hodograph plot
;   - Reading data from an ASCII file
;   - Drawing XY plot curves with both lines and markers
;   - Putting labels on an XY plot
;
;****************************************************
;
; This script was contributed by Haoming Chen from
; LASG/IAP in Beijing, China.
;
; A hodograph plot is a suitable approach in
; describing diurnal variations in the wind vector
; at a given point.
;

load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_code.ncl"
load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_csm.ncl"
load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/contributed.ncl"
load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/shea_util.ncl"

begin

plev = (/ 972,962,953,946,938.7,925,905.8,898 /)

mr = (/9.72,9.5,9.1,9.2,9.1,8.8,7.9,7.5 /)

plev = plev*100.
plev@units = "Pa"	; Convert to Pascals

mr@units = "g/kg"

ptop = min(plev)

psfc = 983*100
psfc@units = "Pa"

dp = dpres_plevel(plev, psfc, ptop, 0)

;total mix ratio
tot_mr = sum(mr*dp)
avg_mr_test = tot_mr/sum(dp)

;Conventional Calculation

print(avg_mr_test)

end