Climatic changes in the Yangtze Delta have played an important role in the emergence, persistence and collapse of civilization. Archaeological excavations in the region over many years have demonstrated that there are several layers of fine sand or organic mud that interrupt the consecutive culture strata in a number of Neolithic culture sites. Continuous biostratigraphical and sedimentological records from the Maqiao cultural site, Shanghai, suggest that the fine sand and organic mud units resulted from expansion of water bodies both by sea-level fluctuations and from increased flooding during cold and humid episodes of Holocene climates. The absence of human settlement from 7240 BP to 5320 BP in the region was mainly caused by higher sea levels resulting from a warm and humid climate. The Neolithic cultures developed under conditions of lower and more stable sea level as well as warmer and dryer climates between about 4410 BP and 3250 BP. A flood-induced lake expansion interrupted the civilization in the region at about 4200 BP. Later, higher water tables and expansion of lakes between 3250 BP and AD 618 under a cold and moist climate temporarily terminated settlement on the delta. Later, during the Tang Dynasty, beginning at about AD 618, the region again became suitable for human settlement under conditions of more favourable climate and lower water tables.

According to the variation pattern of the solar magnetic field polarity and its relation to the relative sunspot number, we established the time series of the sunspot magnetic field polarity index and analyzed the strength and polarity cycle characteristics of the solar magnetic field. The analysis showed the existence of a cycle with about a 22-year periodicity in the strength and polarity of the solar magnetic field, which proved the Hale proposition that the 11-year sunspot cycle is one-half of the 22-year solar magnetic cycle. By analyzing the atmospheric temperature field, we found that the troposphere and the stratosphere in the middle latitude of both the northern and southern hemispheres exhibited a common 22-year quasicycle in the atmospheric temperature, which is believed to be attributable to the 22-year solar magnetic cycle.

Based on the data of 600 years global above class 5 volcanic explosion index (VEI) and the comparison of the northern hemispheric ground temperature, the western pacific high, the northern Atlantic high and the sea surface temperature anomaly (SSTA) in the northern Atlantic westerly region, it is showed that: (1) The global strong volcano activities have obvious century timescale cycles about 88 and 100 years, accounting for about 21.65% of total variance for VEI, an about 33-year interdecadal timescale cycle, and an 11-year cycle associated with solar activity. (2) The western Pacific subtropical high in July has a 33-year period oscillation accordant to the volcanic activity, which is considered to be the response to the 33-year periodic volcanic activity. (3) In the North Atlantic, the volcanic activities inspire the summer North Atlantic sub-tropical high with 88-year cycle oscillation, winter (January) northern Atlantic westerly region SSTA with 100-year oscillation and summer (July) SSTA 88-year cycle oscillation. (4) Analysis shows that the 88-year periodic variation of northern hemispheric ground temperature is the response to the 88-year cycle of volcanic activity.

In this paper, based on the characteristics of the sunspot number, the time sequence of the magnetic index of the sunspot magnetic field is established. The analysis of temperature field spectrum shows that in the air temperature field of the troposphere and stratosphere at the middle latitude of Northern and Southern hemispheres there generally exist cycles with a 22‐year period. The analysis also shows that the cycle of the air temperature field with a 22‐year period is generated by the solar activity with a 22‐year period.

This article analyzes the volcanic activity influences on temperature change in the tropical upper atmosphere (TUA) using sequential regression, case study and comparison. It is shown that the most volcanoinfluenced area in air temperature is in the 70hPa layer of stratosphere at an altitude of about 22km; and the effect gradually decreases beyond or below the height, while the temperature increases in stratosphere but decreases in troposphere at 300hPa near the tropopause. Volcanic activity contributes 45.7% of total variance to the tropical temperature anomaly at 70hPa altitude. Case study on several volcanoes (i.e. Agung, Pinatubo, and El Chichon) of different intensities was conducted. As much as 80% of the temperature anomaly in the TUA would linger for 20 months. Therefore, volcanism is a strong factor causing temperature change in a long period after the explosion.