The tenth IMSC, Beijing, China, 2007 - International Meetings on ...

warm record years may arise by chance in stationary, but serially correlated, series: an
auto-regressive process of order 1 and long-memory process. <strong>The</strong> parameters of these
processes are estimated from the observed data, using the complete record or just part of it.
<strong>The</strong> resulting probabilities, estimated by Montecarlo realizations, hover over 10-4 to 10 -3.
A similar analysis has been performed for the annual temperature averaged in each of the
26 regions defined by Giorgi and Bi (2005), derived from the HadCRU3 data set. Some of
these series start earlier than 1880. <strong>The</strong> autoregressive parameter is estimated for each of
these series, as well as the number of warmest years occurring in 1990-2005. <strong>The</strong>
probabilities of these number of record years arising by chance under this null-hypothesis
varies widely. For some regions, it is as high as 0.1, but for other regions, notably East Asia
and Alaska, they are remarkably small, of the order of 10-6, indicating that for these regions
the late series of warm years would lie even more clearly outside the range of random
fluctuations than for the global annual temperature.
Parallel Sessions:Process Studies
<strong>The</strong> study on Anomalous Atmosphere-Ocean Currents and the Propagation Mechanism for
Warm Signal of Sea Temperature
Speaker: Changrui
Changrui
IAP
changrui2001@163.com
Zhang Qingyun
IAP
Because of the sparse observation over the Ocean, the important problems about the
characteristics of the ocean currents and their relationship with the sea temperature anomaly
during El Niño events are still not completely resolved, although there already have been a few
researchers focused their attentions on this field. In order to deeply investigate the truth behind
the puzzles from a new way, this research is based upon the Simple Ocean Data Assimilation
(SODA) dataset from 1971 to 2000 and the NECP/NCAR reanalysis dataset from 1980 to
2000, which are of high resolution and long time scale. <strong>The</strong>refore, from the departures point of
view, the variations of zonal wind and ocean currents as well as the propagation features of
the sea temperature signal during El Niño events have been investigated by composite
analysis. In this research, special emphasis is placed on the two main types of El Niño events:
the middle-pattern of El Niño and the east-pattern of El Niño. According to the amplitude of the
sea surface temperature anomaly and its characteristics of propagation, the 1982/83, 1991/92
and 1997/98 events are composite for the middle-pattern of El Niño event and the 1972/73 and
1976/77 events for the east-pattern of El Niño event. <strong>The</strong> results show that:
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