Comparing with the domestic verison of DR7, there are some updates for the parameter catalog of DR7_v1.2. The details are described in the following.
(1) Four values of radial velocity including rv_r0, rv_r1, rv_br0, and rv_br1 are added in the MRS Parameter catalog. The rv_r0 and rv_br0 are determined by the cross-correlation method using the red band and the full band of medium-resolution spectra respectively. The rv_r1 and rv_br1 are calibrated velocities of rv_r0 and rv_br0. More details can be refered to Medium Resolution Data Descrption of DR7_v1.2.
(2) The measurement of atmospherical parameters (Teff, logg, [Fe/H]) for cool stars has been improved in MRS Parameter catalog. Instead of the blue band, the red band of medium-resolution spectra is considered when calculating the atmospherical parameters. These cool stars consist of two groups, of which one are stars with Teff smaller than 4000 K, and the other group is cool dwarfs with Teff smaller than 4500 K and logg larger than 3.5.
(3) For the low-resolution part of DR7_v1.2, atmospherical parameters (Teff, logg, [Fe/H]) of M-type stars are determined by comparing the observed spectra to the synthetic spectra. The measurements of these parameters of M-type stars are included in the parameter catalog of low-resolution part.