12!-----reference paper: C. Chen, Paola Malanotte-Rizzoli et al. 2009. Application and comparison of Kalman filters for coastal ocean problems: An experiment with FVCOM, J. Geophys. Res., 114, C05011, doi:10.1029/2007JC004548.
13!-----subroutine: analysis and corresponding subroutines were modified from publicly avaialbe EnKF code package of Geir Evensen.(http://enkf.nersc.no/code)
14!-----subroutine: assimilate and correspnding subroutines were written based on Hunt et al. (2007): Efficient data assimilation for spatiotemporal chaos: A
15!-----local sensemble transform Kalman Filter. Physisa D
16!-----Subroutine: SEIK_analysis and correspoding subroutines was modified from original code source example from Lars, Nerger: A comparison of Error Subspace Kalman Filter