| The relation between the Southern Hemisphere annular mode (SAM) and East Asia Summer Monsoon (EASM) is studied diagnostically. It is found that there is a significantly positive correlation between the boreal spring SAM and summer precipitation in the Yangtze River valley, providing a valuable signal for predicting the precipitation in the region. And then, the mechanism and physical process are examined between them. The essential patterns in global SST variability and the systematic change during 1960/1965-1985 in global SST are also discussed simply. The main results obtained from this thesis are summarized as followed: 1. The relationship between the boreal spring (April-May) Southern Hemisphere annular mode (SAM) and the following summer (June-August) rainfall in China is examined statistically. The results show there is a significantly positive correlation between the boreal spring SAM index (SAMI) and the following summer precipitation in the middle and lower reaches of the Yangtze River valley. In the spring, an anticyclone centered in the Mongolia Plateau in Eurasia occurs according to the spring strong SAM. Meanwhile the anomalous northerlies prevail from the middle latitudes of East Asia to South China throughout northeast of China. These anomalous circulations may continue to the following summer and weaken East Asian Summer Monsoon (EASM). The western ridge of western Pacific subtropical high strengthens and extends westward in summer following the spring strong SAM. These circulation anomalies are related to the above than normal precipitation in the middle and lower reaches of the Yangtze River valley. Moreover, the spring strong SAM is followed by increased ascending vertical velocity, specific humidity and relative humidity, which provide necessary water vapor conditions for increasing the summer precipitation in the middle and lower reaches of the Yangtze River valley, and vice versa. The boreal spring SAM variation provides a potential valuable signal for predicting the summertime precipitation in the middle and lower reaches of the Yangtze River valley. 2. The role of the SSTs in the Indian Ocean (IO) and South China Sea (SCS) in therelationship between the summer precipitation in the Yangtze River valley and the boreal spring SAM is examined in this thesis. When the boreal spring SAM index (SAMI) is anomalous, significant SST anomaly (SSTA) occurs in middle and high latitudes of the South Indian Ocean (SIO) and the North Indian Ocean (NIO), which may persist to the summertime and is enhanced in the NIO. Based on the SST partition in the 10 and SCS, the further analyses reveal that the SAM in the boreal spring may force SST and induce SSTA in middle and high latitudes of the SIO. The SSTA may persist to the summer. The anomalies may propagate from middle and high latitudes of the SIO to the NIO (including the Arabian Sea and Bay of Bengal) and SCS and reinforce the SSTA in these regions. The study about the relation between the East Asian summer monsoon (EASM) and SST indicates that the summer SSTA in the NIO associated with the EASM is similar to that associated with the boreal spring SAM, but the sighs are opposite. It suggests that the SSTA in the 10 and SCS is a bridge between the boreal spring SAM and summer precipitation in the Yangtze River valley. The basic process is that the strong (weak) boreal spring SAM may lead to the high (low) SST anomalies in middle and high latitudes in the SIO, which propagate to the Arabian Sea, Bay of Bengal and SCS. The high (low) SSTs in these regions conduce to the above (under) normal summer precipitation in the Yangtze River valley by the weakened (strengthened) EASM.3. Radiation process and heat exchange on the interface between ocean and atmosphere in the 10 are discussed in the influence of the spring SAM on EASM. The strong spring SAM events are associated with the weakened upward radiation flux and heat flux in mid-high latitudes of SIO, in favor of the higher than normal SST. The flux anomalies in equatorial Indian Ocean according to the strong SAM events are helpful for the lower than normal SST. The flux anomalies in NIO are associated with decreased upward heat flux and increased downward radiation flux, in favor of the higher than normal SST;and vice versa. The further analyses indicate that the radiation flux anomalies in middle and high latitudes of SIO mainly result from the net long-wave radiation variability and in NIO from the netshortwave radiation process variability. The cloud cover variabilities connected with the spring SAM events alter likely the shortwave radiation process in NIO. The decreased upward latent heat flux associated with strong SAM events probably result in the reduced low-cloud cover. So, the decreased low-cloud cover reflects the less shortwave radiation and the incident shortwave radiation increased, in favor of the higher than normal SST in the region;and vice verso.This isn't incompatible with the result that the SST anomalies in SIO propagate to NIO and aroused the SST anomalies in this region. It showed only that the latent heat flux, the low-cloud cover and the short-wave radiation associated with the strong or weak SAM events in NIO are all relevant with the SST anomalies in NIO. In sum, the spring SAM events force SST in mid-high latitudes of SIO;the SST anomalies, latent heat flux, low-cloud cover and solar wave flux are all relevant with the spring SAM events;the mechanism of the propagation of SST anomalies from mid-high latitudes of SIO to NIO is still an open question.4. There is a systematic short-term trend from decadal-interdecadal scale in spring, summer, autumn and annual global SST during 1960/1965-1985. The SSTs in middle latitudes of SIO, the middle and eastern equatorial Pacific and South Atlantic were increasing and SSTs in the Indian Ocean on south of Africa and the middle latitudes of North Pacific were out-of-phase. There was also short-term increasing in SAMI and PDO1. The systematic short-term trend in global SSTs was probably connected with the SAM and PDO. In winter, the systematic short-term SSTs changes occur in lower and middle latitudes of 10, the middle latitudes of North Pacific, the middle and eastern equatorial Pacific and South Atlantic. It correlated significantly with PDO and the relation with was blurry.5. The global main SST patterns are examined for the period of 1854-2002 (149a) and 1951-2002 (52a) in all of four seasons. The first EOF mode of global SST variability shows a linear trend in the recent 50 years. Sea surfaces in middle latitudes of North Pacific, the northern North Atlantic and some regions in South Pacific were cooling. Meanwhile sea surfaces in other regions were warming. The linear trend was back to 1910s in the 149a time series data. The trend during1854-1910s was opposite with during 1910-2002. Sea surfaces in middle latitudes of North Pacific, the northern North Atlantic and some regions in South Pacific were warming and the rest regions were cooling during 1854-19I0s. The second EOF modes both in 149a and in 51 a show ENSO pattern, the dipole mode in South Atlantic and North Pacific, the similar SST variabilities in both eastern and western equatorial Indian Ocean in winter and spring;the opposite SST variabilities in between eastern and western equatorial Indian Ocean in summer and autumn. The third EOF mode is Antarctic circumpolar region-the rest pattern indicating that SST variability in Antarctic circumpolar region is opposite with in North Pacific and North Atlantic. It is the primary interdecadal pattern in global SST variability. In the recent 50a time series data, the pattern is apparent in summer and autumn and unconspicuous in winter and spring. However, the pattern exists apparently in all of four seasons in the 149a time series data. It can be seen that the pattern went through the "positive-negative-positive-negative" phases during the period of 1854-2002.
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