Publication Abstracts

Dai 1996

Dai, A., 1996: Global Precipitation Variability and Its Relationship with Other Climate Changes. Ph.D. thesis. Columbia University.

Station records of monthly precipitation from 1900 to 1988 were analyzed. The 1st leading mode of variation in global (mostly land) precipitation is an ENSO-related multi-year oscillation, with above one standard deviation (σ) decreases in Australia-Indonesia region during SON and JJA seasons of the El Niño year, up to 1.5 σ increases in the southern United States from the end of the El Niño year to MAM in the following year, and above 0.5 σ precipitation changes in many other regions. The changes are in opposite sign during the cold events of ENSO cycles. The 2nd leading mode reveals an increasing trend during the period over middle and high latitudes while it represents a weak decreasing trend in low latitudes. In North Atlantic surrounding regions, a coherent precipitation pattern was found to be associated with the North Atlantic Oscillation. Extreme precipitation events in Australia, southern Africa and India are often associated with ENSOs. The observed anomalies of precipitation, cloudiness, and diurnal temperature range (DTR) and their relationships support the notion that recent global warming has enhanced the global hydrological cycle and resulted in more thick, precipitating clouds, which are likely responsible for the decreasing trend in continental DTR. Model experiments suggest that changes in large-scale vertical motion, either associated with pressure centers or the ITCZ, are found very effective in producing precipitation anomalies and likely responsible for the observed negative correlation between temperature and precipitation anomalies during spring and summer. During winter months, midlatitude winter storms are a major source of precipitation anomalies and could induce positive T-P correlation in the region. Model calculations showed that the temperature and precipitation changes during the 1940-1988 period could result in a cumulative biospheric carbon sink of ∼20±5 GtC (1 GtC = 1015gC) (located in northern midlatitudes). ENSO-induced temperature and precipitation anomalies can induce a net biospheric carbon source of ∼2 GtC to the atmosphere during warm events, and are likely responsible for the observed multi-year variations in atmospheric CO2.

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BibTeX Citation

@phdthesis{da02000x,
  author={Dai, A.},
  title={Global Precipitation Variability and Its Relationship with Other Climate Changes},
  year={1996},
  school={Columbia University},
  address={New York, N.Y.},
}

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RIS Citation

TY  - THES
ID  - da02000x
AU  - Dai, A.
PY  - 1996
BT  - Global Precipitation Variability and Its Relationship with Other Climate Changes
PB  - Columbia University
CY  - New York, N.Y.
ER  -

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