EarthRef.org Reference Database (ERR)
Development and Maintenance by the EarthRef.org Database Team

Detailed Reference Information
Hastenrath 1998
Hastenrath, S. (1998). Contribution to the circulation climatology of the eastern equatorial Pacific: Lower-atmospheric jets. Journal of Geophysical Research 103: doi: 10.1029/98JD02007. issn: 0148-0227.

Novel data sets have been evaluated to reappraise the annual cycle of atmospheric circulation over the Pacific. In the eastern Pacific, cross-equatorial surface winds from the southern hemisphere generate an oceanic cold tongue immediately to the south of the equator. The associated lower-tropospheric thickness pattern entails a minimum of absolute topography in the midtroposphere near the equator, and together with the small Coriolis parameter this causes a jet stream of up to 10 ms-1 at 700--600 mbar centered at 0¿--2 ¿N. The jet is most intense in late boreal winter because then the near-equatorial surface low-pressure trough is flat. The jet is fed by lower-tropospheric convergence over equatorial South America and by upper tropospheric convergence and subsidence over a narrow equatorial zone of the eastern Pacific. Over the central Pacific a jet of up to 10 ms-1 is found at 10¿--12 ¿N and 925--850 mbar, while friction brakes the flow in the layer of steepest meridional pressure gradient near the surface. This lower-tropospheric jet, as the surface pressure gradient, is also strongest in late boreal winter. Overall, the NCEP analyses resolve the near-surface circulation less well than the long-term ship observations. However, the midtropospheric equatorial jet over the eastern Pacific is also borne out by the 1967--1971 radiosoundings over Galapagos, and the lower-tropospheric trade wind jet over the central Pacific was also identified from the intense radiosonde program of the March--April 1967 Line Islands Experiment. ¿ 1998 American Geophysical Union

BACKGROUND DATA FILES

Abstract

Keywords
Meteorology and Atmospheric Dynamics, Meteorology and Atmospheric Dynamics, Climatology, Meteorology and Atmospheric Dynamics, General circulation, Meteorology and Atmospheric Dynamics, Tropical meteorology
Journal
Journal of Geophysical Research
http://www.agu.org/journals/jb/
Publisher
American Geophysical Union
2000 Florida Avenue N.W.
Washington, D.C. 20009-1277
USA
1-202-462-6900
1-202-328-0566
service@agu.org
Click to clear formClick to return to previous pageClick to submit