function RHrf = RHcalc(T,P,Q)
% computes relative humidity given T,P, & Q
% as in COARE35

es = 6.1121.*exp(17.502.*T./(T+240.97)).*(1.0007+3.46e-6.*P);
em = Q.*P./(0.378.*Q+0.622);
RHrf = 100*em./es;
end