Further analysis of the relationship between circulation anomaly patterns and tropical convection

Journal Article · Sat Mar 20 04:00:00 EST 1993 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/92JD02952· OSTI ID:6617405

Mo, K C; Kousky, V E ^[1]

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1. NOAA, Washington, DC (United States)

Tropical-extratropical connections are investigated for 250-mbar stream function fluctuations in both intraseasonal and interannual bands. The principal modes of anomalous 250-mbar stream function are computed and related to anomalous outgoing longwave radiation (OLR), which is used as a proxy for deep tropical convection. The leading mode for both boreal winter and summer displays a large zonally symmetric component, which appears in both the intraseasonal (IS) and interannual (IA) bands. In the IS band, the dominant mode is an oscillation with a period of 48 days. Correlations between the principal component of this mode and OLR anomalies indicate that this pattern is directly related to convection in the tropical Pacific. The second mode for the boreal winter consists of a wave train from the Pacific Ocean east-northeastward to western North America and then east-southeastward to the subtropical Atlantic Ocean. This mode also exists in both IA and IS bands. Simultaneous and lagged correlations between the amplitude time series of this mode and OLR anomalies indicate that extreme amplitudes of this wave train are preceded by extremes in the OLR anomalies (cloud band activity) in the subtropical North Pacific. Enhanced cloud band activity in the vicinity of Hawaii, associated with an anomalous cyclonic 250-mbar circulation in the same region precedes the maximum development of a 250-mbar ridge south of the Aleutian Islands, trough over western North America and another ridge along the east coast of the United States. The second mode for boreal summer (June-August) is associated with variations of the Asian monsoon. 36 refs., 11 figs., 1 tab.

• OSTI ID: 6617405
• Journal Information: Journal of Geophysical Research; (United States), Journal Name: Journal of Geophysical Research; (United States) Vol. 98:D3; ISSN JGREA2; ISSN 0148-0227
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540110*
AMPLITUDES
ANNUAL VARIATIONS
ATLANTIC OCEAN
ATMOSPHERIC CIRCULATION
CONVECTION
CORRELATIONS
DEVELOPED COUNTRIES
ENERGY TRANSFER
FLUCTUATIONS
GLOBAL ASPECTS
HAWAII
HEAT TRANSFER
ISLANDS
MASS TRANSFER
NORTH AMERICA
PACIFIC OCEAN
RADIATIONS
SEAS
SEASONAL VARIATIONS
SOLAR FLUX
SOLAR RADIATION
STELLAR RADIATION
SURFACE WATERS
TROPICAL REGIONS
USA
VARIATIONS