Normal Mode Initialization with Elementary Surface Friction

Ballish, Bradley Alan; Baer, F.

doi:10.1175/1520-0493(1985)113<0241:nmiwes>2.0.co;2

Cited by 3 publications

(3 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Correspondingly, R z 0.65 for the diabatic case. This is a further demonstration that the dynamic balance at the surface involves diabatic forces (Errico, 1983;Ballish and Baer, 1985).…”

Section: Analyses Of Mode Coefficientsmentioning

confidence: 68%

“…Then a diabatic initialization, which includes surface drag, reduces A V,, by a factor of two in the lowest level. This result indicates that the balance in the small-scale, shallow modes is indeed diabatic, as described by Errico (1984) and Ballish and Baer (1985). If the surface drag term is excluded from the DIAB 9V-20T initialization, then the errors (not shown) are similar to those of the adiabatic case.…”

Section: Analyses Of Divergent Windsmentioning

confidence: 73%

“…The AVd for ADIAB 9V-20T (not shown) is qualitatively similar, except in the lowest model a-level, where values greater than 5 m/s occur. These large, near surface errors occur in the adiabatic, 9 vertical mode case because the actual model balance for the shallow modes is dominated by the diabatic surface drag (Errico, 1984;Ballish and Baer, 1985). The structures of the 9V-20T initializations are different from those in the previous figures both because more vertical modes are affected and because fewer modes are selected by the shorter period cutoff.…”

Section: Analyses Of Divergent Windsmentioning

confidence: 84%

See 2 more Smart Citations

A comparison of various normal-mode initialization schemes and the inclusion of diabatic processes

Errico¹,

Rasch²

1988

Tellus A

View full text Add to dashboard Cite

The field changes produced by various normal mode initialization schemes are compared. Dynamically balanced data are obtained from a climate simulation using a forecast model. The data are first degraded by a linear initialization, and then a nonlinear initialization is used in an attempt to recover the original fields. The nonlinear initializations include both diabatic and adiabatic schemes, applied to various sets of modes defined using both equivalent depths and natural periods as criteria.Results indicate that diabatic initialization improves specification of the meridional mass streamfunction (i.e., the zonal wavenumber zero Hadley circulation) compared with adiabatic ~nitialization. However, for zonally varying fields, the difference is less dramatic. An exception occurs when shallow modes are initialized, in which case near-surface fields are better specified using diabatic initialization. Errors in the tropical divergent wind field are typically half their true value, for either diabatic or adiabatic initializations. For vertical modes 1 -2, errors in specification of mode coefficients are typically less than 209; of their true r.m.s. values. For shallower modes whose natural periods are less than one day, these errors are greater than 407;. but for those longer period modes, errors are greater than 80",.The prognostic equation for a single mode coefficient is examined. Results suggest that, for medium depth, large horizontal scale tropical modes, a significant error source is the balance condition itself. For these modes, the time scales of their diabatic forcing, observed behavior, and natural (linear) behavior are all similar. In this case, the tendency term in the equations is not negligible

show abstract

“…Correspondingly, R z 0.65 for the diabatic case. This is a further demonstration that the dynamic balance at the surface involves diabatic forces (Errico, 1983;Ballish and Baer, 1985).…”

Section: Analyses Of Mode Coefficientsmentioning

confidence: 68%

Section: Analyses Of Divergent Windsmentioning

confidence: 73%

Section: Analyses Of Divergent Windsmentioning

confidence: 84%

See 1 more Smart Citation

A comparison of various normal-mode initialization schemes and the inclusion of diabatic processes

Errico¹,

Rasch²

1988

Tellus A

View full text Add to dashboard Cite

show abstract

Dynamic Normal Mode Initialization for a Limited-area Model

Satomura

1988

Journal of the Meteorological Society of Japan

View full text Add to dashboard Cite

The dynamic normal mode initialization scheme (DNI) proposed by Sugi is applied to a limited-area model. Performance of two integration schemes for DNI is examined, and it is shown that Okamura's time integration scheme is inefficient and a backward implicit scheme is appropriate for DNI applied to the limited-area model. All physical processes can be included in the integration cycle of DNI.Horizontal wind and precipitation rate are compared using a control forecast, a forecast with the nonlinear normal mode initialization (NMI), and with DNI. The deformation of horizontal wind near the mountains is reconstructed by DNI better than by NMI. The area-averaged precipitation is not largely improved by DNI, but the rms error of the precipitation from the control forecast is smaller in DNI than in NMI in the first three hours.

show abstract

A comparison of various normal-mode initialization schemes and the inclusion of diabatic processes

Errico

Rasch

1988

Tellus A: Dynamic Meteorology and Oceanography

View full text Add to dashboard Cite

Normal Mode Initialization with Elementary Surface Friction

Cited by 3 publications

References 0 publications

A comparison of various normal-mode initialization schemes and the inclusion of diabatic processes

A comparison of various normal-mode initialization schemes and the inclusion of diabatic processes

Dynamic Normal Mode Initialization for a Limited-area Model

A comparison of various normal-mode initialization schemes and the inclusion of diabatic processes

Contact Info

Product

Resources

About