Scilab Function
Last update : 22/8/2006

huf_val_mod - construct Hufnagel-Valley refractive atmospheric model.

Calling Sequence

[ram]=huf_val_mod(nlayers,layer_heights, pseudowind[,tf])



construct Hufnagel Valley refractive atmospheric model. this model implements a multilayer approximation to the analytic atmospheric model proposed by Hufnagel and Valley. Paraphrasing Sasiela p. 60, the analytic model is: Cn^{2}(h)= .00594 (W/27)^{2} (1e-5*h)^{10}exp(-h/1000) + 2.7e-16 exp(-h/1500) + A exp(-h/100). where W is the pseudowind and A is a parameter that is usually set equal to 1.7e-14. The HV-21 model has this value for A, and W is equal to 21. This model is sometimes referred to as the HV 5/7 model. (Note - h is apparently in meters)

Sasiela tabulates the turbulence moments for 4 different values of the pseudowind W. They are reproduced in the table below.

To generate a multilayer approximation to this model, the user must supply a vector of layer heights to this function. The convention for assigning turbulence weights to the layers is as follows. The C_{n}^{2} profile is integrated from the ground to the midpoint between the first and second layer, and this weight is assigned to the first layer. The profile is integrated from this point to the midpoint between the second and third layers, and this weight is assigned to the second layer. For the highest layer, the profile is integrated from the midpoint between the second highest layer and the highest layer to infinity. Note that this procedure does not necessarily preserve theta_0 in the table above, but does preserve r_0.


	for i=1:5


Chen jingyuan, Gan guangyong (IAPCM, Beijing,China.)

See Also

power_spectrum ,   ref_atm_lay ,   ell_cer_pac_mod ,   ell_mau_kea_mod ,   pal_dimm_mass_mod ,   ref_atm_model ,   slcsat_day_mod ,   slcsat_night_mod ,   tmt_srd_v13_cn2_mod ,   gemini_glao_study_mod ,   get_atm_mod_dwfh ,   get_atm_mod_layers ,   atm_mod_layers_fits ,   atm_mod_lay_number ,   atm_mod_lay_heights ,   atm_mod_lays_transform ,   atmosphere ,