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The periodicities of the climate change have long been explored by researchers not only because they reflect the inherent characteristics of the climate systems, but also because they are the foundations of climate-change predictability. This paper reports the periodicities of the hydroclimate variations reconstructed from a lacustrine sequence at Tiancun section (TC section) in the Luoyang Basin within the Central Plains of China and the sequence covers the first half of the Holocene. Our reconstruction shows that the hydroclimate variations at the TC section during the period from ∼10,135 and ∼ 5890 cal. yr BP were well corresponding with the effective soil moisture variations recorded by the stalagmite δ13C sequence at the Magou Cave. This corresponding relationship suggests that when the effective soil moisture increases (i.e., more negative δ13C values), the ratio of evaporation over precipitation in the paleolake at the TC section decreased, resulting in lower CaCO 3 content. It also suggests that when the effective soil moisture increases, more inflowing water entered the paleolake, resulting in coarser sediments. Our reconstruction also shows that the hydroclimate variations or lake level variations in the Luoyang Basin were characterized by millennial-scale quasi-periodicities that were most likely paced by the changes in ITCZ (Inter-tropical Convergent Zone) position and also by alterations in ENSO-like phase. And, both (ITCZ and ENSO) were most likely regulated by the solar activity. Our further analysis shows that the hydroclimate in the Luoyang Basin also experienced centennial-scale variations. Specifically, the grain size data express the following cycles: 692-year, 538-year, 217-year, 170-year and 123-year, all at the 99% confidence level. And, the CaCO 3 content data express the following cycles: 202-year, 184-year, 169-year and 85-year, all at the 99% confidence level. These cycles are approximately coincident with the widely-reported solar-activity cycles. • This paper reports the periodicities of the hydroclimate variations reconstructed from a lacustrine sequence in the Central Plains of China and the sequence covers the first half of the Holocene. • The hydroclimate variations were primarily paced by changes in ITCZ position and also by alterations in ENSO-like phase. And, both (ITCZ and ENSO) were most likely regulated by solar activity. • The centennial-scale hydroclimate variations were approximately coincident with the widely-reported solar-activity cycles. [ABSTRACT FROM AUTHOR]

• Long-term evolution trend of wind and waves in China's offshore was investigated. • A novel approach was proposed to evaluate wind-wave joint exploitation potential. • Joint utilization guarantee rate of wind and waves in China's offshore was 67 %–87 %. • AO, AMO and Niño 3.4 affected WS and H s from high to low latitudes, respectively. • Impact of ENSO on WS and H s in SCS could reach 3.92 m/s and 1.15 m, respectively. Assessing wind and waves resources and analyzing their evolution are crucial for the exploitation of wind and wave energy. This paper utilized ERA5 reanalysis data to investigate the distribution characteristics, long-term evolution, and influencing factors of wind speed (WS) and significant wave height (H s) in China's offshore regions. It showed that over the past 60 years, the Bohai Sea experienced a significant downward trend in WS (−0.632 cm/s/yr) and H s (−0.135 cm/yr). The Yellow Sea exhibited a downward trend in WS, but no change trend was observed in H s (p > 0.05). The H s in the East China Sea (ECS) and South China Sea (SCS) showed upward trends, increasing by 0.191 cm/yr and 0.262 cm/yr, respectively. The concept of energy utilization guarantee rate (EUGR) was introduced to evaluate the complementarity and synergy between wind and wave resources. The ECS and SCS were found to possess ample wind resources, with an EUGR of approximately 80 %. The combined EUGR of wind and wave energy in the Bohai Sea, Yellow Sea, ECS, and SCS amounted to 67.41 %, 72.29 %, 86.86 %, and 84.10 %, respectively. The southeastern coastal waters of China exhibited significant complementary and synergistic effects between wind and waves, making them suitable for the joint utilization of wind and wave energy. The distribution and evolution of wind and waves in China's offshore varied due to diverse climate conditions prevailing in different regions. From high to low latitudes, the Bohai Sea was mainly controlled by AO, while the Yellow Sea was jointly affected by AO and AMO; The ECS and SCS were mainly affected by AMO and Niño 3.4, respectively. During El Niño/La Niña years, the SCS exhibited a decrease/increase in WS and H s , with a lag of ∼3 months in response to ENSO. The variation amplitude of WS and H s could reach 3.92 m/s and 1.15 m, respectively. [ABSTRACT FROM AUTHOR]

The decline of ancient societies has been often associated with hydroclimate instabilities. In this paper, we report phytolith records from the Yangtze River Delta of China, to reconstruct middle and late Holocene climate dynamics, and understand societal impacts. Our findings reveal that the area experienced a consistent decline in temperature and humidity punctuated by several rapid climate shifts. A distinct dry episode from 7000 to 6000 cal yr BP likely developed in response to weakened Atlantic Meridional Overturning Circulation (AMOC) and a southward shift of the intertropical convergence zone (ITCZ), resulting in a weakened East Asian summer monsoon (EASM) and a strengthened East Asian winter monsoon (EAWM). This dry condition would have favoured the emergence of dryland and facilitated rice cultivation in the lower Yangtze region. Another dry episode at 4500–4000 cal yr BP, which was probably associated with the widespread 4.2 ka climate event, and linked to a further retreat of the ITCZ and highly variable ENSO intensity, led to highly unstable hydroclimate conditions in the region. We argue that this event disrupted social resilience and culminated in the cultural collapse at the end of Liangzhu Culture. • Cooling trend since 8000 cal yr BP in response to decline of summer insolation. • Dry episodes at 7000–6000 and 4500–4000 cal yr BP. • Strength of AMOC and position of ITCZ jointly modulates the EASM. • Neolithic societal resilience shows varied responses to each dry episode. [ABSTRACT FROM AUTHOR]

Rainfall erosivity (RE) is the ability of rainfall to cause soil or regolith erosion. Understanding the spatial distribution and temporal trends of RE is critical for assessing soil erosion risk and improving upon soil conservation planning. The aim of this paper is to study the temporal and spatial changes in RE in the Huaihe River Basin, China. This will be based on daily precipitation data from 67 meteorological stations in the Huaihe River Basin for the period 1971 to 2016. The assessment of the resulting RE values involved inverse distance-weighted (IDW) interpolation, Sen's slope estimation, and the Mann-Kendall nonparametric test. In addition, the possible influence of the El Niño – Southern Oscillation (ENSO) on RE in the Huaihe River Basin will be examined by the use of Cross Wavelet Transform (XWT) and Wavelet Coherence (WTC), where the relationship between RE and the multivariate ENSO index (MEI) are analyzed. The results showed that the spatial distribution of RE is characterized by it increasing from west to east and north to south. In most areas, the annual RE has increased slightly, while this upward trend in the southeastern part of the study area was more significant. The rainfall erosivity of rainstorms (RE-SM) in the Huaihe River Basin played a leading role in the annual RE, and 97% of the stations displayed the order of importance of the different categories of rainfall as rainfall erosivity of rainstorms (RE-SM) > rainfall erosivity of heavy rain (RE-HR) > rainfall erosivity of moderate rain (RE-MR). Over monthly time scales, the RE was the highest in July, while it was lowest in December, with the monthly differences being apparent. The RE in the Huaihe River Basin were relatively large during non-El Niño/La Niña periods and relatively small during El Niño/La Niña periods. Finally, correlations between RE and the MEI in various parts of the basin showed different characteristics over time and space, with both displaying similarities and differences. • Spatial–temporal variations in rainfall erosivity in the study area were quantified. • Rainfall erosivity of rainstorms (RE-SM) dominates in different categories of rainfall erosivity. • El Niño and La Niña events have different impacts on rainfall erosivity in the Huaihe River Basin. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, we present the first annual oxygen isotope (δ18O) record (1902 to 2004) from the latewood cellulose of trees growing in a temperate-moist forest in southwestern China. Tree-ring δ18O ranges from 12.8 to 18.6‰ and averages 15.2‰. δ18O in the latewood negatively correlates with total cloud cover, relative humidity, and precipitation during the moist months (August to October) from 1951 to 2004 and, to a lesser extent, positively correlates with the temperature in June. Spatial correlation analysis revealed that tree-ring latewood δ18O is more strongly related to variability in regional cloud cover and precipitation in autumn. Tree-ring δ18O negatively correlates with the indices of the Indian summer monsoon (1948 to 2004), the western North Pacific monsoon (1948 to 2004), and with the East Asian summer monsoon (1902 to 2000), suggesting that these monsoons strongly influence the regional climate. Under global warming of last century, we found a strong inverse correlation between tree-ring δ18O and the Southern Oscillation index in different periods, indicating a complex association between the El Niño-Southern Oscillation and the regional climate, which in turn affects tree-ring δ18O. Correlation with the global sea surface temperature (SST) indicates that climatic conditions in the Indian Ocean might play a dominant role in modulating cloud cover and precipitation over the study region during the monsoon seasons. We also found a significant correlation between tree-ring δ18O and SST over the western-north Pacific Ocean. Our results suggest strong links between tropical oceans and an ENSO-like climate with the oxygen-isotope sources and discrimination for trees in the study region. [Copyright &y& Elsevier]