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increment is distributed across the assimilation window ( Bloom et al. 1996 ), time-varying increments for 4DIAU are computed at hourly intervals by 4DEnVar. Lorenc et al. (2015) demonstrate that the filtering properties of IAU described by Polavarapu et al. (2004) apply in an empirical sense to 4DIAU in a hybrid-4DEnVar system because the waves generated by imbalances introduced by the analysis increments are uncorrelated with the slowly varying increments themselves. A confirmation of this result
increment is distributed across the assimilation window ( Bloom et al. 1996 ), time-varying increments for 4DIAU are computed at hourly intervals by 4DEnVar. Lorenc et al. (2015) demonstrate that the filtering properties of IAU described by Polavarapu et al. (2004) apply in an empirical sense to 4DIAU in a hybrid-4DEnVar system because the waves generated by imbalances introduced by the analysis increments are uncorrelated with the slowly varying increments themselves. A confirmation of this result
. , 21 , 521 – 537 , doi: 10.5194/npg-21-521-2014 . Charney , J. G. , and D. M. Straus , 1980 : Form-drag instability, multiple equilibria, and propagating planetary waves in baroclinic, orographically forced, planetary wave systems . J. Atmos. Sci. , 37 , 1157 – 1176 , doi: 10.1175/1520-0469(1980)037<1157:FDIMEA>2.0.CO;2 . Counillon , F. , I. Bethke , N. Keenlyside , M. Bentsen , L. Bertino , and F. Zheng , 2014 : Seasonal-to-decadal predictions with the ensemble Kalman
. , 21 , 521 – 537 , doi: 10.5194/npg-21-521-2014 . Charney , J. G. , and D. M. Straus , 1980 : Form-drag instability, multiple equilibria, and propagating planetary waves in baroclinic, orographically forced, planetary wave systems . J. Atmos. Sci. , 37 , 1157 – 1176 , doi: 10.1175/1520-0469(1980)037<1157:FDIMEA>2.0.CO;2 . Counillon , F. , I. Bethke , N. Keenlyside , M. Bentsen , L. Bertino , and F. Zheng , 2014 : Seasonal-to-decadal predictions with the ensemble Kalman
performed in the 27- and 9-km domains, while all forecasts are conducted in all three domains. The initial conditions from 3 km are interpolated from the 9-km domain. All domains have 37 vertical levels from the surface to 50 hPa. Results shown in all figures are from the 3-km domain. Physical parameterization options include the WRF single-moment 6-class microphysics scheme (WSM6; Hong and Lim 2006 ), the Mellor–Yamada–Janjic (MYJ) planetary boundary layer scheme ( Mellor and Yamada 1982 ), the Kain
performed in the 27- and 9-km domains, while all forecasts are conducted in all three domains. The initial conditions from 3 km are interpolated from the 9-km domain. All domains have 37 vertical levels from the surface to 50 hPa. Results shown in all figures are from the 3-km domain. Physical parameterization options include the WRF single-moment 6-class microphysics scheme (WSM6; Hong and Lim 2006 ), the Mellor–Yamada–Janjic (MYJ) planetary boundary layer scheme ( Mellor and Yamada 1982 ), the Kain
model and thus, in this sense, this approach is more consistent with assumptions made in data assimilation schemes. Over North America, Meng and Zhang (2007) showed that using a combination of different cumulus parameterization schemes improves the performance of the EnKF: this experiment had a smaller bias and a better background error covariance structure than the single scheme. They also found that including model uncertainties from planetary boundary layer (PBL) and microphysical processes had
model and thus, in this sense, this approach is more consistent with assumptions made in data assimilation schemes. Over North America, Meng and Zhang (2007) showed that using a combination of different cumulus parameterization schemes improves the performance of the EnKF: this experiment had a smaller bias and a better background error covariance structure than the single scheme. They also found that including model uncertainties from planetary boundary layer (PBL) and microphysical processes had
