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The Asian summer monsoon (ASM) is a vast climate system, whose variability is critical to the livelihoods of billions of people across the Asian continent. During the past half-century, much progress has been made in understanding variations on a wide range of timescales, yet several significant issues remain unresolved. Of note are two long-standing problems concerning orbital-scale variations of the ASM. (1) Chinese loess magnetic susceptibility records show a persistent glacial-interglacial dominated ~100 kyr (thousand years) periodicity, while the cave oxygen-isotope (δ18O) records reveal periodicity in an almost pure precession band (~20 kyr periodicity)—the "Chinese 100 kyr problem". (2) ASM records from the Arabian Sea and other oceans surrounding the Asian continent show a significant lag of 8–10 kyr to Northern Hemisphere summer insolation (NHSI), whereas the Asian cave δ18O records follow NHSI without a significant lag—a discrepancy termed the "sea-land precession-phase paradox". How can we reconcile these differences? Recent and more refined model simulations now provide spatial patterns of rainfall and wind across the precession cycle, revealing distinct regional divergences in the ASM domain, which can well explain a large portion of the disparities between the loess, marine, and cave proxy records. Overall, we also find that the loess, marine, and cave records are indeed complementary rather than incompatible, with each record preferentially describing a certain aspect of ASM dynamics. Our study provides new insight into the understanding of different hydroclimatic proxies and largely reconciles the "Chinese 100 kyr problem" and "sea-land precession-phase paradox". [ABSTRACT FROM AUTHOR]

Severe persistent drought events during the last 530 years are examined in Arid Central Asia (ACA) by using the data with proxy assimilation from the Last Millennium Climate Reanalysis project version 2.0 (LMR v2.0). According to the results from the LMR v2.0, six severe decadal droughts occurred in ACA during the last 530 years and five of them overlap with the results based on the independent reconstructions of Asian summer precipitation, such as the droughts of 1519–1538 CE, 1545–1561 CE, 1621–1658 CE, 1822–1846 CE, and 1964–1983 CE. The climate anomaly patterns are characterized by opposite anomalies between the high‐latitude and midlatitude Eurasia during the first four well‐agreement droughts, with negative precipitation and positive surface level pressure and 500‐hPa geopotential height anomalies located over midlatitude Eurasia and opposite anomalies over high‐latitude Eurasia. Whereas, during the last well‐agreement drought, opposing pattern of the climate variation observed between in ACA and in the Mediterranean with negative precipitation anomalies and positive 500‐hPa geopotential height anomalies in ACA and opposite anomalies in the Mediterranean. The positive Arctic Oscillation/North Atlantic Oscillation influence is found to dominate the droughts of 1621–1658 CE via a northward migration of the westerlies. While the last drought of 1964–1983 CE produced by the combined impacts of the negative Atlantic Multidecadal Oscillation and Pacific Decadal Oscillation via the Silk Road pattern over the midlatitude Eurasian continent. Key Points: The LMR v2.0 was able to roughly capture five severe decadal droughts occurred in ACA during the last 530 yearsThe climate anomaly patterns over Eurasia during the first four droughts are different with these patterns during the last droughtThe positive AO/NAO influences dominate the drought of 1621–1658 CE, while the negative AMO and PDO played import role on the last drought [ABSTRACT FROM AUTHOR]

Abstract: The interannual teleconnections between the summer North Atlantic Oscillation and summer precipitation in eastern China over the last millennium are investigated in a 1,000‐year simulation by the global climate model Community Climate System Model version 2.0.1. The model was able to roughly produce the general features of the teleconnection influences in eastern China, with negative (positive) precipitation anomalies north of 30°N and positive (negative) precipitation anomalies south of 30°N, associated with the positive (negative) phase of the North Atlantic Oscillation. The composite analysis reveals that the influence of the North Atlantic Oscillation on precipitation in summer in eastern China is chiefly via the “North Atlantic‐Eurasian teleconnection pattern,” which extends from the subtropical North Atlantic to East Asia. [ABSTRACT FROM AUTHOR]