Seasonal and interannual variability of atmospheric heat sources and moisture sinks as determined from NCEP-NCAR reanalysis
- Univ. of California, Los Angeles, CA (United States)
Using the National Centers for Environmental Predictions (NCEP)-National Center for Atmospheric Research (NCAR) reanalysis, distributions of the heat source Q{sub 1} and moisture sink Q{sub 2} between 50{degree}N and 50{degree}S are determined for a 15-yr period from 1980 to 1994. Heating mechanisms operating in various parts of the world are examined by comparing the horizontal distributions of the vertically integrated heat source {l_angle}Q{sub 1}{r_angle} with those of the vertically integrated moisture sink {l_angle}Q{sub 2}{r_angle} and outgoing longwave radiation (OLR) flux and by comparing the vertical distributions of Q{sub 1} with those of Q{sub 2}. In northern winter, the major heat sources are located (i) in a broad zone connecting the tropical Indian Ocean, Indonesia, and the South Pacific convergence zone (SPCZ); (ii) over the Congo and Amazon Basins; and (iii) off the east coasts of Asia and North America. In northern summer, the major heat sources are over (i) the Bay of Bengal coast, (ii) the western tropical Pacific, and (iii) Central America. Heat sources in various regions exhibit strong interannual variability. A long (4-5 yr) periodicity corresponding to the variations in OLR and sea surface temperature (SST) is dominant in the equatorial eastern and central Pacific Ocean, while a shorter-period oscillation is superimposed upon the long-period variation over the equatorial Indian Ocean. The interannual variations of {l_angle}Q{sub 1}{r_angle}, OLR, and SST are strongly coupled in the eastern and central equatorial Pacific. However, the coupling between the interannual variations of {l_angle}Q{sub 1}{r_angle} and OLR with those of SST is weak in the equatorial western Pacific and Indian Ocean, suggesting that factors other than the local SST are also at work in controlling the variations of atmospheric convection in these regions. 62 refs., 11 figs., 1 tab.
- OSTI ID:
- 621418
- Journal Information:
- Journal of Climate, Journal Name: Journal of Climate Journal Issue: 3 Vol. 11; ISSN 0894-8755; ISSN JLCLEL
- Country of Publication:
- United States
- Language:
- English
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