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e_eq_ice_gg

PURPOSE ^

E_EQ_ICE_GG Equilibrium water vapor pressure over ice

SYNOPSIS ^

function [esi] = e_eq_ice_gg(T)

DESCRIPTION ^

 E_EQ_ICE_GG  Equilibrium water vapor pressure over ice

 Calculate the equilibrium water vapor pressure over a plane surface
 of ice according to http://en.wikipedia.org/wiki/Goff-Gratch_equation
 The formula (T in K, Ei in hPa converted):
 
 
 Similarly, the equation for the saturation water vapor pressure over ice is:

 Log10(ei) = -9.09718 (273.16/T - 1)                                          
             - 3.56654 Log10(273.16/ T) 
             + 0.876793 (1 - T/ 273.16) 
             + Log10(ei0) 
 where:
 log stands for the logarithm in base 10
 ei is the saturation water vapor pressure over ice (hPa)
 T is the air temperature (K)
 T0 is the ice-point (triple point) temperature (273.16 K)
 ei0 is e* at the ice-point pressure (6.1173 hPa)

 References:
 http://en.wikipedia.org/wiki/Goff-Gratch_equation
 Goff, J. A., and S. Gratch (1946) Low-pressure properties of water from −160 
 to 212 °F, in Transactions of the American Society of Heating and Ventilating 
 Engineers, pp 95–122, presented at the 52nd annual meeting of the American
 Society of Heating and Ventilating Engineers, New York, 1946.
 Goff, J. A. (1957) Saturation pressure of water on the new Kelvin temperature 
 scale, Transactions of the American Society of Heating and Ventilating Engineers,
 pp 347–354, presented at the semi-annual meeting of the American Society of 
 Heating and Ventilating Engineers, Murray Bay, Que. Canada.
 World Meteorological Organization (1988) General meteorological standards and 
 recommended practices, Appendix A, WMO Technical Regulations, WMO-No. 49.
 World Meteorological Organization (2000) General meteorological standards and
 recommended practices, Appendix A, WMO Technical Regulations, WMO-No. 49, corrigendum.
 Murphy, D. M. and Koop, T. (2005): Review of the vapour pressures of ice
 and supercooled water for atmospheric applications, Quarterly Journal of the 
 Royal Meteorological Society 131(608): 1539–1565. doi:10.1256/qj.04.94

 FORMAT   e = e_eq_ice_gg(T)

 OUT       e = Equilibrium water vapor pressure over ice in [Pa].
 IN       T = Temperature in [K].

CROSS-REFERENCE INFORMATION ^

This function calls: This function is called by:

DOWNLOAD ^

e_eq_ice_gg.m

SOURCE CODE ^

0001 % E_EQ_ICE_GG  Equilibrium water vapor pressure over ice
0002 %
0003 % Calculate the equilibrium water vapor pressure over a plane surface
0004 % of ice according to http://en.wikipedia.org/wiki/Goff-Gratch_equation
0005 % The formula (T in K, Ei in hPa converted):
0006 %
0007 %
0008 % Similarly, the equation for the saturation water vapor pressure over ice is:
0009 %
0010 % Log10(ei) = -9.09718 (273.16/T - 1)
0011 %             - 3.56654 Log10(273.16/ T)
0012 %             + 0.876793 (1 - T/ 273.16)
0013 %             + Log10(ei0)
0014 % where:
0015 % log stands for the logarithm in base 10
0016 % ei is the saturation water vapor pressure over ice (hPa)
0017 % T is the air temperature (K)
0018 % T0 is the ice-point (triple point) temperature (273.16 K)
0019 % ei0 is e* at the ice-point pressure (6.1173 hPa)
0020 %
0021 % References:
0022 % http://en.wikipedia.org/wiki/Goff-Gratch_equation
0023 % Goff, J. A., and S. Gratch (1946) Low-pressure properties of water from −160
0024 % to 212 °F, in Transactions of the American Society of Heating and Ventilating
0025 % Engineers, pp 95–122, presented at the 52nd annual meeting of the American
0026 % Society of Heating and Ventilating Engineers, New York, 1946.
0027 % Goff, J. A. (1957) Saturation pressure of water on the new Kelvin temperature
0028 % scale, Transactions of the American Society of Heating and Ventilating Engineers,
0029 % pp 347–354, presented at the semi-annual meeting of the American Society of
0030 % Heating and Ventilating Engineers, Murray Bay, Que. Canada.
0031 % World Meteorological Organization (1988) General meteorological standards and
0032 % recommended practices, Appendix A, WMO Technical Regulations, WMO-No. 49.
0033 % World Meteorological Organization (2000) General meteorological standards and
0034 % recommended practices, Appendix A, WMO Technical Regulations, WMO-No. 49, corrigendum.
0035 % Murphy, D. M. and Koop, T. (2005): Review of the vapour pressures of ice
0036 % and supercooled water for atmospheric applications, Quarterly Journal of the
0037 % Royal Meteorological Society 131(608): 1539–1565. doi:10.1256/qj.04.94
0038 %
0039 % FORMAT   e = e_eq_ice_gg(T)
0040 %
0041 % OUT       e = Equilibrium water vapor pressure over ice in [Pa].
0042 % IN       T = Temperature in [K].
0043 
0044 % 2010-08-18 Created by Marston Johnston
0045 
0046 function [esi] = e_eq_ice_gg(T)
0047 
0048 if any(T <= 0), error('Temperatures must be greater than 0K!!'); end
0049 
0050 T0  = 273.16;  % K
0051 e0 = 6.1071; % hPa
0052 a = -9.09718;
0053 b = -3.56654;
0054 c = 0.876793;
0055 
0056 % Give the log of saturation vapor pressure over ice in hPa
0057 X = a*((T0./T)-1) + b*log10(T0./T) + c*(1-(T/T0));
0058 
0059 esi = (e0*10.^X)*1e2; % Converts to Pa

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