A Pacific Decadal Oscillation record since 1470 AD reconstructed from proxy data of summer rainfall over eastern China

Abstract

[1] Recent studies indicated that the spatial pattern and temporal variability of summer rainfall over eastern China are well correlated with the Pacific Decadal Oscillation (PDO). Here we used a data set of the drought/flood index (a proxy of summer rainfall) since 1470 AD to reconstruct the annual PDO index. The reconstruction indicates that the PDO is a robust feature of North Pacific climate variability throughout the study period, however, the major modes of oscillation providing the basic PDO regime timescale have not been persistent over the last 530 years. The quasi-centennial (75 -115-yr) and pentadecadal (50 -70-yr) oscillations dominated the periods before and after 1850, respectively. Our analysis suggest that solar forcing fluctuation on quasi-centennial time scale (Gleissberg cycle) could be the pace-maker of the PDO before 1850, and the PDO behavior after 1850 could be due, in part, to the global warming.

Periodic temperature-associated drought/flood drives locust plagues in China

“…Although climatic oscillations at an 80-year period in China is well established (e.g. Wang et al 1981;Shen et al 2006), it should be noted that our study, to our knowledge, is the first to report temperature-driven climatic patterns with a predominant period of 160-170 years in China, a periodic climatic pattern that also drives locust dynamics. Our results suggest that China experienced more droughts and floods in the colder periods than in the warmer periods, but that the association between floods and temperature may vary regionally.…”

Thousand-year-long Chinese time series reveals climatic forcing of decadal locust dynamics

“…The variability in the precipitation index is associated with large-scale atmospheric circulation anomalies, the latitudinal positions of winter storms being shifted southward in wet years and northward in dry years (13). We hypothesize that the temperature and precipitation proxies combined track lowfrequency variability in the East Asian monsoon, which is associated with changes in both temperature and precipitation patterns in China (22)(23)(24). In terms of locust ecology, we hypothesize that temperature is negatively associated with locust abundance at a decadal and regional scale because of increases in suitable breeding habitats during cold and wet periods (with frequent droughts and floods).…”

Cycles and shifts: 1,300 years of multi-decadal temperature variability in the Gulf of Alaska

“…Although, in the twentieth century, GOA temperatures express a strong coherence with the PDO, it cannot be assumed that this teleconnected relationship has been stable through time or that the PDO has always been equally important as present. More comparative analysis is needed with other PDO proxies from North America and Asia (MacDonald and Case 2005;Shen et al 2006;, as well as other proxies expressing decadal oscillatory behavior in the tropics (Evans et al 2001;D'Arrigo et al 2005) to gain insight into the spatial coherence of these multi-decadal signals. Our analysis shows, however, that although oscillatory behavior can be identified in GOA temperatures-and therefore possibly the North Pacific as a whole-the temporal stability and the interaction of these modes of variability, as well as their causes, are not well enough understood at this time.…”