As summarized in the above table, CV5, CV6, and CV7 differ in the control variables they use. CV5 utilizes streamfunction (ψ), unbalanced velocity potential (χu), unbalanced temperature (Tu), pseudo relative humidity (RHs), and unbalanced surface pressure (Ps,u). The pseudo relative humidity is defined as Q/Qb,s, where Qb,s is the saturated specific humidity from the background field. For CV6 the moisture control variable is the unbalanced portion of the pseudo relative humidity (RHs,u). Additionally, CV6 introduces six additional correlation coefficients in the definition of the balanced part of analysis control variables. See the section WRFDA with Multivariate Background Error (MBE) Statistics for more details on this option. Finally, CV7 uses a different set of control variables: u, v, temperature, pseudo relative humidity (RHs), and surface pressure (Ps).