The atmospheric angular-momentum cycle during the tropical Madden-Julian oscillation

Journal Article · Thu Oct 01 04:00:00 EDT 1992 · Monthly Weather Review; (United States)

DOI:https://doi.org/10.1175/1520-0493(1992)120<2252:TAAMCD>2.0.CO;2· OSTI ID:6823836

Weickmann, K M; Khalsa, S J.S.; Eischeid, J ^[1]

---

1. NOAA, Environment Research Lab., Boulder, CO (United States) Colorado Univ., Boulder (United States)

Global-scale wind and outgoing longwave radiation anomalies are documented during the atmospheric angular-momentum (AAM) cycle associated with the Madden-Julian oscillation. Cross-spectral and compositing techniques are applied to 150- and 850-mb National Meteorological Center wind data and outgoing longwave radiation (OLR) data during ten northern winter and summer seasons. Coherent wind and OLR signals are found in the tropics and in the winter hemisphere and are dominated by zonal wavenumbers 0-2. At the time of zero AAM anomaly, anomalous zonal winds are found over the western hemisphere tropics (during northern winter), while convection anomalies tend to be collocated with the seasonal mean Australasian convection. Zonal-mean OLR anomalies are small. As the AAM anomaly increases, the anomalous zonal winds move eastward and poleward, while dipole convection anomalies become established over the oceanic warm pool and result in an east-west shift of the Australasian monsoon. Zonal-mean OLR anomalies tend to be large when the AAM anomalies are large. During northern winter, the inferred frictional torques peak near the time of maximum AAM anomalies, suggesting that pressure torques may also force the angular-momentum changes. 43 refs.

• OSTI ID: 6823836
• Journal Information: Monthly Weather Review; (United States), Journal Name: Monthly Weather Review; (United States) Vol. 120:10; ISSN MWREAB; ISSN 0027-0644
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540110*
ANGULAR MOMENTUM
ATMOSPHERIC CIRCULATION
CONVECTION
ELECTROMAGNETIC RADIATION
ENERGY TRANSFER
HEAT TRANSFER
LONG WAVE RADIATION
MASS TRANSFER
METEOROLOGY
NATURAL CONVECTION
RADIATIONS
RADIOWAVE RADIATION
SOUTHERN OSCILLATION
TORQUE
TROPICAL REGIONS