VPD (饱和水汽压差)

基于HadISDH计算VPD

% 加载数据
load HadISDH_Ta1973_2018.mat; 
load HadISDH_RH1973_2018.mat;
load dem_hadisdh.mat;
% 计算每个月的VPD，保存一行为元胞
Pmsl = 1013.25;     % the air at mean sea level (hpa)
for i = 1:length(HadISDH_RH1973_2018)
    Ta = HadISDH_Ta1973_2018{1,i};                        % the land air temperature (°C)             
    RH = HadISDH_RH1973_2018{1,i};                        % the land relative humidity (%)
    Pmst = Pmsl*((Ta+273.16)./((Ta+273.16)+0.0065*dem_hadisdh)).^5.625;  % dem_hadisdh is the altitude (m)
    Fw = 1+7*0.0001+3.46*0.000001*Pmst;                   % Pmst is the air pressure (hPa)
    SVP = 6.112*Fw.*exp((17.67*Ta)./(Ta+243.5));          % saturated vapor pressure (kPa)
    AVP = RH/100.*SVP;                                    % actural vapor pressure (kPa)
    VPD = SVP-AVP;
    HadISDH_VPD1973_2018{1,i} = VPD;
end

基于ERA计算VPD

% 加载数据
load ERA_Ta1979_2018.mat; 
load ERA_Td1979_2018.mat;
load dem_era.mat;

% 计算每个月的VPD，保存一行为元胞
Pmsl = 1013.25;                                                            % the air at mean sea level (hpa)
for i = 1:length(ERA_Ta1979_2018)
    Ta = ERA_Ta1979_2018{1,i};                                             % the land air temperature (°C)             
    Td = ERA_Td1979_2018{1,i};                                             % the dew point tempetature (°C) 
    Pmst = Pmsl*((Ta+273.16)./((Ta+273.16)+0.0065*dem_era)).^5.625;        % dem_hadisdh is the altitude (m)
    Fw = 1+7*0.0001+3.46*0.000001*Pmst;                                    % Pmst is the air pressure (hPa)
    SVP = 6.112*Fw.*exp((17.67*Ta)./(Ta+243.5));                           % saturated vapor pressure (kPa)
    AVP = 6.112*Fw.*exp((17.67*Td)./(Td+243.5));                           % actural vapor pressure (kPa)
    VPD = SVP-AVP;
    ERA_VPD1979_2018{1,i} = VPD;
end

参考文献

Increased atmospheric vapor pressure deficit reduces global vegetation growth