On Atmospheric Blocking Types and Blocking Numbers

Schilling, Heinz-Dieter

doi:10.1016/s0065-2687(08)60035-7

Cited by 11 publications

(10 citation statements)

References 17 publications

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“…Hansen, 1986;Schilling, 1986). When these episodes are very long-lived the second conversion C(A,,,K,,,) is also large in all probability (Schilling, 1987).…”

Section: Baroclic Activity Of Ultralong Wavesmentioning

confidence: 98%

“…In order to retrieve observed scalewise dissipation rates (e.g., Schilling, 1986) we are forced to set A2 = 50/a2 in (B1). Having computed the spectral coefficients for w and dQ/dt in each layer we can recombine the series for the fields in l-rp-space.…”

Section: Appendixmentioning

confidence: 99%

“…Certainly, flow patterns show the integral effect of different cooperating processes rather than being a reliable indicator of a well defined mechanism. Moreover, it can easily be shown that dynamics with very different characteristics build up similar synoptic patterns (e.g., Schilling, 1986). A more objective definition of the event to be analyzed was given in the studies of Tsay and Kao (1978a,b), Hansen (1986) and Itoh (1983).…”

Section: Introductionmentioning

confidence: 99%

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Baroclinic outbreak episodes in wavenumber domain

Schilling¹

1988

Tellus A: Dynamic Meteorology and Oceanography

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In contrast to the common definition of anomalous atmospheric flow by persistent and localized geopotential height anomalies, we define significant excursions from normal conditions by persistent anomalies of a single spectral energy conversion on a circumpolar scale. Whereas amplification of transient geopotential height or streamfunction anomalies generally involves a variety of possible processes and complex energetics, our approach defines strongly distorted energetics of a certain kind. With data covering 10 years (1967)(1968)(1969)(1970)(1971)(1972)(1973)(1974)(1975)(1976), we study baroclinic energy conversions from zonal mean to zonal wavenumber m available potential energy, C(A,A,), when these exceed the long-term average by more than a standard deviation for at least 3 consecutive days. During these episodes, called baroclinic outbreaks (BO), C(A,K,,,) and the kinetic energy of wave m, K,,,, are also large in all probability. Although short BO cases are frequent for all m, there is a secondary maximum of frequency at about 7 days for the ultralong wave m = 2. Composite energetics of BO's are presented, and a profound transformation of the 500 mb flow is shown for a long lasting m = 2 BO event.

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“…Hansen, 1986;Schilling, 1986). When these episodes are very long-lived the second conversion C(A,,,K,,,) is also large in all probability (Schilling, 1987).…”

Section: Baroclic Activity Of Ultralong Wavesmentioning

confidence: 98%

Section: Appendixmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Baroclinic outbreak episodes in wavenumber domain

Schilling¹

1988

Tellus A: Dynamic Meteorology and Oceanography

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“…Daily records of the baroclinic conversions C (A,A,,,) for m=2,3 or 4 (averaged over the troposphere and latitudes north of 40"N) are noteworthy, since they reveal that episodes of large baroclinic input from the zonal mean are more frequent than classical linear instability theories would have predicted (e.g. Hansen, 1986;Schilling, 1986). When these episodes are very long-lived the second conversion C(A,,,K,,,) is also large in all probability (Schilling, 1987).…”

Section: Baroclic Activity Of Ultralong Wavesmentioning

confidence: 99%

Baroclinic outbreak episodes in wavenumber domain

Schilling¹

1988

Tellus A

Self Cite

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In contrast to the common definition of anomalous atmospheric flow by persistent and localized geopotential height anomalies, we define significant excursions from normal conditions by persistent anomalies of a single spectral energy conversion on a circumpolar scale. Whereas amplification of transient geopotential height or streamfunction anomalies generally involves a variety of possible processes and complex energetics, our approach defines strongly distorted energetics of a certain kind. With data covering 10 years (1967)(1968)(1969)(1970)(1971)(1972)(1973)(1974)(1975)(1976), we study baroclinic energy conversions from zonal mean to zonal wavenumber m available potential energy, C (A,A,), when these exceed the long-term average by more than a standard deviation for at least 3 consecutive days. During these episodes, called baroclinic outbreaks (BO), C(A,K,,,) and the kinetic energy of wave m, K,,,, are also large in all probability. Although short BO cases are frequent for all m, there is a secondary maximum of frequency at about 7 days for the ultralong wave m = 2. Composite energetics of BO's are presented, and a profound transformation of the 500 mb flow is shown for a long lasting m = 2 BO event.

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“…Energetics analyses of the observed circulation field often assert an enhanced baroclinic conversion in the amplified planetary waves, implying that the amplification involves a process of baroclinic instability (e.g., Schilling, 1986). However, the linear stability analyses of planetary waves with zonal basic states (e.g., Simmons and Hoskins, 1976;Hartmann, 1979) indicate major discrepancies with obervations.…”

Section: Introductionmentioning

confidence: 99%

Untitled

1989

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This study investigates low-frequency, unstable planetary waves in realistic basis states of January 1979, using three-dimensional spectral primitive equations derived by orthonormal vertical structure functions and Hough harmonics. Eigenfrequencies, modal structures, and energetics are contrasted for the zonal basic state and the zonally varying basic state. Three selected unstable modes are extensively examined. One is the Green mode in the planetary waves, and the other two are deep Charney modes having different meridional structures. We find that the Green mode of wavenumber 1 in the zonally varying basic state shows notable transient growth in the first internal vertical component during its life-cycle. One of the deep Charney modes becomes stationary at a preferred geographical location with nearly barotropic structure. The other deep Charney mode, which shows a monopole structure in the zonal basic state, becomes a dipole structure in the zonally varying basic state. The northern part of the dipole structure shows westward propagation with transient growth in amplitude at a preferred location.The results suggest that the large-scale Pacific blockings during the winter are, at least in part, related to the low-frequency Charney mode having a dipole structure. A possible connection between the amplification of planetary waves and the Green mode in zonally varying basic states is also discussed.

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On Atmospheric Blocking Types and Blocking Numbers

Cited by 11 publications

References 17 publications

Baroclinic outbreak episodes in wavenumber domain

Baroclinic outbreak episodes in wavenumber domain

Baroclinic outbreak episodes in wavenumber domain

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