#!/usr/bin/env python3
"""
NAME:
  wcm_twc.py

PURPOSE:
  Demostration of coding the WCM equations to calculate Total Water Content.

SYNTAX:
  ./wcm_twc.py

PARAMETERS:
  None

EXAMPLE:
  ./wcm_twc.py

MODIFICATIONS:
  David Delene <delene@aero.und.edu> -  2022/10/25

NOTES:
  Equations based on the WCM 2000 manual, see
  /nas/Instruments/SEA_WCM2000/WCM2000User.pdf
 
  Data is from the 2022 IMPACTS field project.
  Parameters is from the January 11, 2022 file at 16:55:53 (60953 sfm).

  Equations are giving in the 2022/10/20 slide presentation, see 
  http://aerosol.atmos.und.edu/AtSc594_Fall2022/index.html

Copyright 2022 David Delene <delene@aero.und.edu>

This program is distributed under the terms of the GNU General Public License

This file is part of Airborne Data Processing and Analysis (ADPAA).

ADPAA is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

ADPAA is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with ADPAA.  If not, see <http://www.gnu.org/licenses/>.
"""

# Using IMPACTS data on January 11, 2022 data at 16:55:53 (60953 sfm).
# Define Sensor Total Power (watts).
P_sense_total = 11.36

# Define Sensor Dry Power (watts).
P_sense_dry   = 5.0

# Calculate Sensor Wet Power (watts).
P_sense_wet = P_sense_total - P_sense_dry

# Define ambient (static) Pressure (mbars).
# Using IMPACTS data on January 11, 2022 data at 16:55:53 (60953 sfm).
P_amb = 829.5

# Calculate evaporation temperature (C).
# Equation is from the WCM manual.
T_evap = 32.16 + 0.1801*P_amb-(2.391e-4)*(P_amb**2)+(1.785e-7)*(P_amb**3)-(5.19e-11)*(P_amb**4)

# Calculate Latent Heat of Evaporation (cal/g).
# Equation is from the WCM manual.
L_evap = 594.4 - 0.484*T_evap - (7.0e-4)*T_evap**2

# Define ambient temperature (C).
# Using IMPACTS data on January 11, 2022 data at 16:55:53 (60953 sfm).
T_amb = -12.0

# Define true air speed (m/s).
# Using IMPACTS data on January 11, 2022 data at 16:55:53 (60953 sfm).
TAS = 116.0

# Define length of the Sense Element (mm).
L_sense = 10.008 

# Define width of the Sense Element (mm).
W_sense = 2.4380 

# Calculate Total Water Content.
# Equation is from the WCM 2000 manual page 65.
#   LWC = (P_sense * 2.389e5) / ((L_evap + 1.0*(T_evap-T_amb))*TAS*L_sense*W_sense))
# The 2.389e-5 term is to convert (cal/s * mm^2) to (watts * m^2)
TWC = ( P_sense_wet * (2.389e5) ) / ( ( L_evap + 1.0*(T_evap-T_amb) ) * TAS * L_sense * W_sense)

# The calculated value can be compared to value available in the d1 file.
print("Total Water Content = ",TWC," (g/m^3)")