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Land use and cover change (LUCC) is the most direct manifestation of the interaction between anthropological activities and the natural environment on Earth’s surface, with significant impacts on the environment and social economy. Rapid economic development and climate change have resulted in significant changes in land use and cover. The Shiyang River Basin, located in the eastern part of the Hexi Corridor in China, has undergone significant climate change and LUCC over the past few decades. In this study, we used the random forest classification to obtain the land use and cover datasets of the Shiyang River Basin in 1991, 1995, 2000, 2005, 2010, 2015, and 2020 based on Landsat images. We validated the land use and cover data in 2015 from the random forest classification results (this study), the high-resolution dataset of annual global land cover from 2000 to 2015 (AGLC-2000-2015), the global 30 m land cover classification with a fine classification system (GLC_FCS30), and the first Landsat-derived annual China Land Cover Dataset (CLCD) against ground-truth classification results to evaluate the accuracy of the classification results in this study. Furthermore, we explored and compared the spatiotemporal patterns of LUCC in the upper, middle, and lower reaches of the Shiyang River Basin over the past 30 years, and employed the random forest importance ranking method to analyze the influencing factors of LUCC based on natural (evapotranspiration, precipitation, temperature, and surface soil moisture) and anthropogenic (nighttime light, gross domestic product (GDP), and population) factors. The results indicated that the random forest classification results for land use and cover in the Shiyang River Basin in 2015 outperformed the AGLC-2000-2015, GLC_FCS30, and CLCD datasets in both overall and partial validations. Moreover, the classification results in this study exhibited a high level of agreement with the ground truth features. From 1991 to 2020, the area of bare land exhibited a decreasing trend, with changes primarily occurring in the middle and lower reaches of the basin. The area of grassland initially decreased and then increased, with changes occurring mainly in the upper and middle reaches of the basin. In contrast, the area of cropland initially increased and then decreased, with changes occurring in the middle and lower reaches. The LUCC was influenced by both natural and anthropogenic factors. Climatic factors and population contributed significantly to LUCC, and the importance values of evapotranspiration, precipitation, temperature, and population were 22.12%, 32.41%, 21.89%, and 19.65%, respectively. Moreover, policy interventions also played an important role. Land use and cover in the Shiyang River Basin exhibited fluctuating changes over the past 30 years, with the ecological environment improving in the last 10 years. This suggests that governance efforts in the study area have had some effects, and the government can continue to move in this direction in the future. The findings can provide crucial insights for related research and regional sustainable development in the Shiyang River Basin and other similar arid and semi-arid areas.

El Niño‐Southern Oscillation (ENSO) is the most dominant interannual signal of climate variability and profoundly affects river flooding globally, especially in East Asia. However, ENSO also has ∼2,000 and ∼1,000‐year cycles, but due to the lack of flood records with sufficient length, little is known about the ENSO's impact on floods at these millennial timescales. Here we test this in the middle‐lower Yangtze River by reconstructing the first Holocene flood record with optically stimulated luminescence and 14C ages of flood deposits. We find the periods with high flooding probability generally correspond with intervals of weakened solar activity. Importantly, the flood record displays 2,000 and 1,000‐year cycles similar to the ENSO record, and band‐pass filter results show the two records are synchronous at these bands. Our results reveal a persistent control of ENSO on millennial‐scale hydroclimatic variability in the Yangtze basin and likely other basins. El Niño‐Southern Oscillation (ENSO) is the prominent pattern of interannual climate variability, profoundly affecting the river flow and flooding at the global scale. However, the ENSO's interannual cycle was strongly damped or even non‐existent in most of the Holocene, compared with a more robust millennial periodicity. It remains unclear whether a link exists between the flood and ENSO at millennial timescales due to the lack of sufficiently long flood series. Here we test this in the Yangtze River (YR) because ENSO has the most significant impact on this drainage area. We compiled the most detailed flood ages over the middle and lower YR to reconstruct the Holocene flood record. We found that the flood variations have prominent 2,000 and 1,000‐year cycles, and they exhibit in‐phase relationship with ENSO at these cycles, suggesting a persistent modulation of ENSO on the flooding at millennial timescales in the middle and lower Yangtze basin. This study contributes to a more comprehensive understanding of the driving forces of floods in the Yangtze catchment at millennial timescales, thereby aiding to accurately assess flood hazards and flooding prediction in hydroclimatic modeling for the densely populated Yangtze basin. We reconstructed the Holocene flood record for the middle and lower Yangtze River by compiling optically stimulated luminescence and 14C ages of flood depositsThe flood record displays clear 2,000 and 1,000‐year cyclesThe flood record is synchronous with El Niño‐Southern Oscillation at 2,000 and 1,000‐year cycles We reconstructed the Holocene flood record for the middle and lower Yangtze River by compiling optically stimulated luminescence and 14C ages of flood deposits The flood record displays clear 2,000 and 1,000‐year cycles The flood record is synchronous with El Niño‐Southern Oscillation at 2,000 and 1,000‐year cycles

Landscape evolution models (LEMs) are essential tools for analyzing tectonic-climate interactions and reproducing landform-shaping processes. In this study we used a LEM to simulate the evolution of the mountains from the central Hexi Corridor in the northeastern Tibetan Plateau, where the climate is arid and the surface processes are relatively uniform. However, there are pronounced differences in the topography between the mountains around the central Hexi Corridor. The East Jintanan Shan, West Jintanan Shan and Heli Shan are located in the northern part of the corridor; and the Yumu Shan in the southern part. Firstly, several representative areas were selected from these mountains to analyze the topographic characteristics, including the uniform valley spacing, local relief, and the outlet number. Secondly, a LEM for these areas was constructed using the Landlab platform, and the landscape evolution was simulated. With uniform valley spacing and other topographic characteristics as the criteria, we compared the realistic and simulated terrain for different model ages. Finally, based on the similarity of the simulated and realistic terrain, we estimated the timing of the initial uplift and the uplift rate of the four mountain ranges. The results are consistent with previous geological and geomorphological records from these youthful stage mountains that have not yet reached a steady state. Our findings demonstrate that LEMs combined with topographic characteristics are a reliable means of constraining the timing of the initial uplift and the uplift rate of the youthful stage mountain. Our approach can potentially be applied to other youthful stage mountains and it may become a valuable tool in tectonic geomorphology research.

The Yellow River Basin (YRB) is characterized by active geological and tectonic processes, rapid geomorphological evolution, and distinct climatic diversity. Correspondingly, major disasters in the YRB are characterized by varied types, extensive distributions, and sudden occurrences. In addition, major disasters in the YRB usually evolve into disaster chains that cause severe consequences. Therefore, major disasters in the YRB destroy ecologies and environments and influence geological and ecological safety in the basin. This paper systematically reviews research on geological and surface processes, major disaster effects, and risk mitigation in the YRB, discusses the trends and challenges of relevant research, analyzes the key scientific problems that need to be solved, and suggests prospects for future research based on the earth system science concept. Themes of research that should be focused on include geological, surface and climatic processes in the YRB and their interlinking disaster gestation mechanisms; formation mechanisms and disaster chain evolutions of giant landslides in the upper reach of the YRB; mechanisms and disaster chain effects of loess water-soil disasters in the middle reach of the YRB; occurrence patterns and amplifying effects of giant flood chains in the lower reach of the YRB; and risk mitigations of major disasters in the YRB. Key scientific problems that need to be solved are as follows: how to reveal the geological, surface and climatic processes that are coupled and interlinked with gestation mechanisms of major disasters; how to clarify the mutual feedback effects between major disasters and ecology; and how to develop a human-environmental harmony-based integrated risk mitigation system for major disasters. Prospects for future studies that follow the earth system science concept include the following: highlighting interdisciplinary research to reveal the interlinked disaster gestation mechanisms of the geology, surface and climate in the YRB in the past, present, and future; forming theories to clarify the regional patterns, dynamic mechanisms, and mutual-feedback effects between disaster chains and ecology in the YRB on land and in rivers in the region; solving technological bottlenecks to develop assessment models and mitigation theories for integrated risks in the YRB by following the human-environment harmony concept; and finally, establishing a demonstratable application pattern characterized by “whole-basin coverage” and “zonal controls”, thereby guaranteeing ecological and geological safety in the basin and providing scientific support for ecological conservation and high-quality development of the YRB.

The upper Yellow River drains the central and northeastern Tibetan Plateau. Understanding the origin of this river is essential for unraveling the interplay between fluvial incision, basement uplift, and climate change. However, the formation age of the upper Yellow River is highly debated, with estimates ranging from Eocene to late Pleistocene. In order to clarify the history of the upper Yellow River, we present a heavy‐mineral dataset from drill core in the Yinchuan Basin, a depositional sink at the end of the upper Yellow River course. Our results reveal that the drainage area of the upper Yellow River (i.e., northeastern Tibetan Plateau) has been serving as a major sediment source region for the Yinchuan Basin since at least 3.3 Ma. A late Pleistocene formation of the upper Yellow River, and erosion of neighboring deserts or bounding mountains as an explanation for thick sediment accumulations in this area, is thus ruled out. The Yellow River, the sixth longest in the world, is often called “the cradle of Chinese civilization.” However, due to high sediment loads, it often flows above the level of surrounding farm fields in the Yinchuan‐Hetao Basin, the depositional zone of the upper Yellow River. Catastrophic flooding has occurred several times here in the recent past. Thus, the river is also called “China's Sorrow.” Understanding where the vast amount of sediments in the Yinchuan‐Hetao Basin came from would help to guide river management. Here we present a first investigation of sediment sources in the Yinchuan Basin using heavy‐mineral data of long drill cores spanning the last 3.3 million years. Our results suggest that the majority of the sediments in this region were transported from the northeastern Tibetan Plateau by the upper Yellow River and not from erosion of the neighboring deserts/drylands or mountains. Only during the last 10,000 years might human activities have increased erosion of neighboring deserts/drylands, causing a provenance shift. We present provenance evidence for establishment of the upper Yellow River since at least the late PlioceneThe evidence from the Yinchuan Basin drill core supports a prolonged history of the upper Yellow RiverThe sediments in the Yinchuan Basin were transported from the northeastern Tibetan Plateau mainly by the Yellow River

The avulsion and overflow of river courses during floods, a result of channel siltation above the alluvial plain, is a cause of major natural disasters, including huge property damage and destruction of farmlands. The most sensitive to such risks is the very densely populated area of the Yellow River lower reaches, one of China's most important grain‐producing regions. Problems caused by excessive siltation are a critical issue that should be addressed with full knowledge of sediment‐generation processes, and provenance studies are essential to provide fundamental information for effective environmental management. The Sanmen Gorge is the key region where the great sediment mass produced upstream is conveyed from the middle reaches of the Yellow River to its lower reaches. This study of the terrace sequence exposed along the Sanmen Gorge combines geomorphological observations and provenance analysis based on U‐Pb zircon geochronology and heavy minerals to provide a history of sediment transport through time. The combination of previous research and the outcome of the present study demonstrate that before the Yellow River was formed as an integrated sediment‐routing system, sediments fed into the North China Plain were largely derived from local sources. Instead, after the formation of the Sanmen Gorge, huge quantities of sediment, also derived from the Qinling mountains and stored in the Fenwei basin, were flushed into the North China lowlands by the Yellow River. Such an event took place at 1.2 Ma and has since then impacted severely on floodplain landscape and eventually profoundly affected human activities in the region. Alluvial plains with their fertile lands and plenty of water have served as the birthplace of civilization. However, the same rivers are also a cause of harm and destruction impacting agricultural civilizations during floods. The Chinese civilization originated in the lower Yellow River alluvial plain, which has long been a very important area of food production and population growth. Yellow River is one of Earth's largest rivers and has one of the highest sediment concentrations, fueled by very rapid erosion of fine‐grained sediment stored in the Chinese Loess Plateau and the Fenwei basin. After flowing rapidly through the Sanmen Gorge, the Yellow River slows down and deposits part of its huge sediment mass, causing extremely rapid accumulation in the lower reaches, where the river bed is raised well above the adjacent lowlands, thus representing a perilous threat to surrounding farmlands and urban centers. By investigating the composition and provenance of sediments of the terrace sequences exposed along the Sanmen Gorge, we can reconstruct the evolution of the Yellow River through time. Understanding river behavior and how sediment is generated and transported from the mountain region to the alluvial plain provides the knowledge necessary for more effective environmental management. The Sanmen Gorge formed between 3.7 and 1.2 million years agoSediment provenance shows major changes after the integration of Yellow River drainageModern sediment transport is affected by reservoir construction and human activities The Sanmen Gorge formed between 3.7 and 1.2 million years ago Sediment provenance shows major changes after the integration of Yellow River drainage Modern sediment transport is affected by reservoir construction and human activities

Hilltop curvature (CHT) can record erosional responses to tectonic forces and/or climate change. Although CHThas a linear relationship with the erosion rate, which is a significant advantage over traditional indicators, it is not widely used, mainly because it requires high‐resolution terrain data. Previous studies show that terrain steepness is strongly correlated with catchment‐wide erosion rates in the Qilian Shan. This relationship enables us to test the potential of CHTbased on medium‐resolution terrain data (e.g., Tan DEM‐X with a resolution of ∼12 m) as an indicator of the erosion rate. We selected three typical sites in the Qilian Shan with evenly spaced ridge valleys and a continuous soil cover. At each site, we produced a high‐resolution digital surface model (DSM) using uncrewed aerial vehicles (UAVs), and then compared CHTfrom the UAV DSM with that from Tan DEM‐X, via LSDTopoTools. The results show that both Tan DEM‐X and the UAV DSM record similar spatial patterns of CHT, although the magnitudes vary between the three selected areas. We then examined the relationship between CHTbased on Tan DEM‐X and the catchment‐wide erosion rate in the Qilian Shan. CHThas a linear relationship with the erosion rate in an area of clastic rocks, where the erosion rate is below 400 mm/Kyr. CHTextracted by Tan DEM‐X is superior to the mean basin slope in predicting the erosion rate in this clastic rock landscape. Overall, our results demonstrate the utility of Tan DEM‐X in calculating CHTto indicate the erosion rate. Erosion occurs when Earth surface material is worn away and moved by natural forces such as wind and water. The erosion rate represents the rate at which the surface elevation decreases. Hilltop curvature extracted by terrain analysis software combined with terrain data can provide a rapid estimate of the erosion rate. However, the coverage of high‐resolution terrain data used in previous studies is very sparse. At present, the most widely terrain data with global coverage is Tan DEM‐X. In this study, we determined whether the hilltop curvature extracted based on Tan DEM‐X can predict the erosion rate. This was done by comparing the hilltop curvature extracted from Tan DEM‐X with that from high‐resolution terrain data, and then examined the linear relationship between hilltop curvature based on Tan DEM‐X and the erosion rate in the Qilian Shan in China. The trends of hilltop curvature between different areas recorded by Tan DEM‐X and high‐resolution terrain data were consistent, and the hilltop curvature based on Tan DEM‐X was linearly related to the erosion rate in an area of clastic sedimentary rocks. We suggest that Tan DEM‐X can be used to estimate the erosion rate in areas lacking high‐resolution terrain data. We compared hilltop curvatures extracted from Tan DEM‐X and high‐resolution terrain data on different spatial scalesHilltop curvature based on Tan DEM‐X can indicate the erosion rate at the catchment scaleIn an area of clastic rocks with erosion rates below 400 mm/Kyr, hilltop curvature has a linear relationship with the erosion rate We compared hilltop curvatures extracted from Tan DEM‐X and high‐resolution terrain data on different spatial scales Hilltop curvature based on Tan DEM‐X can indicate the erosion rate at the catchment scale In an area of clastic rocks with erosion rates below 400 mm/Kyr, hilltop curvature has a linear relationship with the erosion rate

Fluvial terraces are important geomorphic markers for modern valley development. When coupled with numeric ages, terraces can provide abundant information about tectonic, climatic, paleohydrological and the paleoenvironmental changes. On the basis of the paleomagnetic, electron spin resonance (ESR) and optically stimulated luminescence (OSL) dating, in addition to an investigation of local loess-paleosol sequences, we confirmed that 13 fluvial terraces were formed, and then preserved, along the course of the Upper Weihe River in the Sanyangchuan Basin over the past 1.2 Ma. Analyses of the characteristics and genesis of these terraces indicate that they resulted from the response of this particular river system to climate change over an orbital scale. These changes can further be placed within the context of local and regional tectonic uplift, and represent an alternation between lateral migration and vertical incision, dependent upon the predominance of climatic and tectonic controls during different periods. Most of the terraces are strikingly similar in that they have several meters of paleosols which have developed directly on top of fluvial deposits located on the terrace treads, suggesting that the abandonment of terraces due to river incision occurred during the transitions from glacial to interglacial climates. The temporal and spatial differences in the distribution patterns of terraces located on either side of the river valley indicate that a tectonic inversion occurred in Sanyangchuan Basin at ~0.62 Ma, and that this was characterized by a transition from overall uplift to depression induced by fault activity. Synthesized studies of the Basin’s terraces indicate that formation of the modern valley of the Upper Weihe River may have begun in the late Early Pleistocene between 1.4–1.2 Ma.

It is generally assumed that increased dust accumulation rate (DAR) on the Chinese Loess Plateau (CLP) is associated with intensified inland Asian aridification. However, the timescales and area that any such association operates over is unclear. In this study, we demonstrate a lack of correlation between the southern CLP loess DAR variations and aridification over the past 130 ka, which does not support a direct link between high DAR and intensified inland Asian aridification over millennial to tens of millennial timescales. Instead, we propose that loess DAR variation is more likely determined by wet‐dry cycles and associated loose sediment production and availability via fluvial and glacial processes. Aridification is a global challenge facing humanity. As such, there is a pressing need to understand changes in aridification over a range of scales, as well as their causes. Arid inland Asia is the largest middle‐latitude arid region, and mineral dust emitted from here is found downwind in the Chinese Loess Plateau (CLP) loess, North Pacific Ocean sediments, and even Greenland ice. As a result, North Pacific and CLP sediments are frequently used to infer inland Asian aridification history. Underpinning this is the assumption that faster dust accumulation corresponds to increased inland Asian aridification. By contrast, here we demonstrate that fast dust accumulation during cycles within the Ice Age on the southeastern CLP correspond instead to periods of increased East Asian river erosion associated with intensified dry‐wet climatic contrasts. Thus, dust accumulation is decoupled from inland Asian aridification variations. This challenges one of the most basic foundations in inland Asian aridification research. This study has broad implications for understanding the responses and feedbacks of atmospheric dust in climate systems, dust‐climate modeling assumptions, understanding of inland Asian aridity history and its causes, and interpretations of far field dust accumulation records in, for example, North Pacific sediments and Greenland ice‐cores. Sedimentary evidence is utilized to systematically test the role of inland Asian aridification in Chinese Loess Plateau (CLP) dust accumulationInland Asian aridification is not the dominant control on CLP dust deposition at millennial and tens of millennial timescalesThis underscores the important role of fluvial sediments in supplying sediments to the CLP and local impacts on dust deposition Sedimentary evidence is utilized to systematically test the role of inland Asian aridification in Chinese Loess Plateau (CLP) dust accumulation Inland Asian aridification is not the dominant control on CLP dust deposition at millennial and tens of millennial timescales This underscores the important role of fluvial sediments in supplying sediments to the CLP and local impacts on dust deposition

Afforestation is an appropriate approach to control soil erosion, but consumes extra water resources. It also exerts feedbacks on local precipitation, affecting the water availability for water‐limited areas. The Chinese Loess Plateau (LP) has implemented the world's largest afforestation program to mitigate severe soil erosion. However, it remains unclear how the atmospheric water cycle responds to large‐scale afforestation under climate change. Here we show that afforestation elevates precipitation in rainy season by intensifying the atmospheric water cycle over the LP. Results show the upward trend of vegetation coverage fraction increased by 3.15% decade−1and climatological precipitation increased by 54.62 mm after launching the large‐scale afforestation in 1999. Such afforestation also enhanced evapotranspiration by 22.56 mm. We found the moisture inflow and outflow continuously decreased, but more atmospheric moisture was retained since the rate of decline of inflow was less than that of outflow. Using a dynamic precipitation recycling method, we explored changes in precipitation recycling and components of the atmospheric water budget. The precipitation recycling ratio increased from 9.16 ± 0.35 to 10.18 ± 0.28% after the afforestation. Both external and internal branches of the atmospheric water cycle have been strengthened, and their contributions to the increased precipitation are 84.93% and 15.07%, respectively. The afforestation caused a more humid atmosphere, heightened soil moisture‐vegetation‐precipitation feedback, stronger moisture convergence, and more clouds; these changes favored precipitation generation. This study advances the understanding of how afforestation affects regional climate from a precipitation recycling perspective, further assisting decision‐makers to establish sustainable afforestation strategies. More atmospheric moisture is gained by the Loess Plateau after large‐scale afforestationPrecipitation recycling ratio increases by 1.02% and more advected and evaporated moisture is converted to precipitation after afforestationContributions of external and internal branches of the atmospheric water cycle to increased precipitation are 84.93% and 15.07%, respectively More atmospheric moisture is gained by the Loess Plateau after large‐scale afforestation Precipitation recycling ratio increases by 1.02% and more advected and evaporated moisture is converted to precipitation after afforestation Contributions of external and internal branches of the atmospheric water cycle to increased precipitation are 84.93% and 15.07%, respectively

The Gongga Mountain is the largest area of modern glaciation in the Hengduan Mountains and, with a summit elevation of 7556 m, is the highest mountain on the eastern margin of the Tibetan Plateau. During the Quaternary glacial-interglacial cycles the Gongga Mountain was extensively and repeatedly glaciated, and glacial landforms and outwash deposits from multiple glaciations are well-preserved in valleys, in basins, and on piedmonts. To constrain the glacial chronology of the eastern slope of Gongga Mountain, sample sites were selected based on the distribution and weathering of glacial tills, relationships among glacial deposits, and soil development on moraines. Dating of the tills and glaciofluvial deposits was undertaken with electron spin resonance (ESR) and optically stimulated luminescence (OSL). The ages of the glacial deposits can be divided into four clusters: 2.2±0.5, 11.9±0.6, 35.9±2.7-58.0±6.3 and 119.2±15.9-194.2±32.8 ka. Five glacial advances in this region have been identified, which are equivalent in age to the Little Ice Age (LIA), Neoglaciation, marine oxygen isotope stage (MIS) 2, mid-MIS3, and MIS6. The largest local last glacial maximum (LGML) occurred on Gongga Mountain during mid-MIS3, characterized by a cold-humid climate, rather than the global Last Glacial Maximum (LGMG) of MIS2. The Gongga, Nanmenguangou (NMGG) and Yajiageng Glaciations occurred during the late part of the last glacial cycle, the middle of the last glacial cycle and the penultimate glacial cycle, respectively. On the basis of geomorphological, sedimentological, and compositional characteristics, landforms of the Moxi Platform and terraces can be grouped by facies and geochronology. In combination with the dating results, this analysis indicates the basal part of the Moxi Platform between Xinxin and the Moxi Hotel is correlative with the till of the Nanguanmen Glaciation (mid-MIS3). This basal unit has occasional lenses of glaciofluvial sandy gravel and lacustrine sediments. The remainder of the Moxi Platform and the terraces beside the platform are glaciofluvial deposits occasionally mixed with debris flow deposits and range in age from MIS3 to Holocene.The Gongga Mountain is the largest area of modern glaciation in the Hengduan Mountains and, with a summit elevation of 7556 m, is the highest mountain on the eastern margin of the Tibetan Plateau. During the Quaternary glacial-interglacial cycles the Gongga Mountain was extensively and repeatedly glaciated, and glacial landforms and outwash deposits from multiple glaciations are well-preserved in valleys, in basins, and on piedmonts. To constrain the glacial chronology of the eastern slope of Gongga Mountain, sample sites were selected based on the distribution and weathering of glacial tills, relationships among glacial deposits, and soil development on moraines. Dating of the tills and glaciofluvial deposits was undertaken with electron spin resonance (ESR) and optically stimulated luminescence (OSL). The ages of the glacial deposits can be divided into four clusters: 2.2±0.5, 11.9±0.6, 35.9±2.7-58.0±6.3 and 119.2±15.9-194.2±32.8 ka. Five glacial advances in this region have been identified, which are equivalent in age to the Little Ice Age (LIA), Neoglaciation, marine oxygen isotope stage (MIS) 2, mid-MIS3, and MIS6. The largest local last glacial maximum (LGML) occurred on Gongga Mountain during mid-MIS3, characterized by a cold-humid climate, rather than the global Last Glacial Maximum (LGMG) of MIS2. The Gongga, Nanmenguangou (NMGG) and Yajiageng Glaciations occurred during the late part of the last glacial cycle, the middle of the last glacial cycle and the penultimate glacial cycle, respectively. On the basis of geomorphological, sedimentological, and compositional characteristics, landforms of the Moxi Platform and terraces can be grouped by facies and geochronology. In combination with the dating results, this analysis indicates the basal part of the Moxi Platform between Xinxin and the Moxi Hotel is correlative with the till of the Nanguanmen Glaciation (mid-MIS3). This basal unit has occasional lenses of glaciofluvial sandy gravel and lacustrine sediments. The remainder of the Moxi Platform and the terraces beside the platform are glaciofluvial deposits occasionally mixed with debris flow deposits and range in age from MIS3 to Holocene.

Abstract: The Shagou loess section recorded the evolution information of severe sandstorms in the Tengger Desert during the Last Interglacial (MIS 5). By analyzing the grain size data of the loess samples using the grain size class-standard deviation, we selected the grain size component between 209 and 550 μm to reconstruct the evolution history of the severe sandstorms in the Tengger Desert during the Last Interglacial. The results indicate that there were at least 12 periods of frequently occurring severe sandstorms in that location over this time period. There were two periods in each of S1SS1 and S1SS2, four periods in S1LL1, three periods in S1LL2 and one in S1LL4. The occurrence frequency and intensity of the severe sandstorms presented a characteristic increase from the early to the late period of the Last Interglacial. Combined with the calcium carbonate results, this evidence suggests that climatic change is closely related to sandstorms. A warm and wet climate could restrict the occurrence of severe sandstorms; conversely, a cold and dry climate easily induces severe sandstorms. Meanwhile, with a warm and dry climate background, the relationship between climatic change and the occurrence of sandstorms is quite complex: severe sandstorms are also able to occur in such a climate. A cold and dry climate, however, does not mean a certainty of severe sandstorms.

Afforestation is a major anthropogenic forcing to the global and regional climate. However, the biophysical impacts of large‐scale afforestation on local temperature in temperate regions remain unclear, due to the closely matched but compensating radiative and non‐radiative effects. The Grain for Green Program (GFGP) is a large‐scale afforestation program implemented over the Loess Plateau (LP) in China. The GFGP thus provides an ideal platform to explore the temperature effect of afforestation. This study investigated such a temperature effect through long‐term, high‐resolution simulations incorporating satellite observations in a coupled land‐atmosphere model. With an optimal combination of physical schemes proposed by this study, we greatly improved the accuracy of regional climate modeling. The results reveal that the afforestation caused a significant decline (−0.50% yr−1) in albedo. An increment in net shortwave radiation mainly led to an increment in net radiation (7.95 W m−2). The afforestation also led to an increment in sensible heat flux (3.78 W m−2). Consequently, the afforestation caused a warming effect (0.36°C) in 2‐meter air temperature at the inter‐annual scale. At the intra‐annual scale, there was a cooling effect in July and August, while other months demonstrated a warming effect. The radiative effect dominated local temperature change induced by the afforestation over the LP. Therefore, the large‐scale afforestation contributed to the local warming trend. Our findings highlight the temperature effect of afforestation, and imply that more attention should be paid to future revegetation to carefully assess its potential influence on regional climate. Incorporating satellite observation improved accuracy of regional climate modelingAfforestation caused an annual warming effect over the Loess Plateau and a cooling effect only in July and August at intra‐annual scaleRadiative effect dominated local temperature change induced by afforestation Incorporating satellite observation improved accuracy of regional climate modeling Afforestation caused an annual warming effect over the Loess Plateau and a cooling effect only in July and August at intra‐annual scale Radiative effect dominated local temperature change induced by afforestation

Glacier surging is a dynamic instability that affects the flow of some glaciers, modifying the glacier area, surface velocity, and surface elevation. It is also among the major causes of ice dams and glacier lake floods. Previous studies have shown that in the West Kunlun Mountains| (WKM) where a cluster of surge‐type glaciers had been found, the glaciers were relatively stable in recent years. Nevertheless, the surge cycle and its impact on glacier changes on a regional scale are poorly understood. In this study, we updated the surge‐type glacier inventory of the WKM using the detailed changes in glacier length, surface velocity, and surface elevation during the 1972–2020 period using 78 Landsat optical images, 86 Sentinel‐1 synthetic aperture radar (SAR) images, and three digital elevation models of the WKM. The updated results show that among the 423 glaciers in the WKM, 10 are confirmed as surge‐type glaciers, three are likely surge‐type glaciers, and five are possible surge‐type glaciers. Furthermore, these 18 glaciers account for 63% of the total glacier area. During the period analyzed, there were marked changes in the lengths, areas and surface elevations of all surge‐type glaciers, while those of the non‐surge‐type glaciers were relatively stable. These results appear to indicate that the observed regional trends of glaciers in the WKM recently may be related to the existence of surge‐type glaciers. Furthermore, the surge‐type glacier underwent advance after accelerating for 3–4 years, which could be used to forecast when glacier termini may advance and avoid the possible catastrophic damages. Glacier surging is a form of irregular motion of a glacier, which rapidly transports a volume of ice, followed by a longer slowdown period. In this study, we employed a vast archive of optical and synthetic aperture radar satellite images to monitor the glaciers change in the West Kunlun Mountains (WKM). The results revealed the existence of 18 surge‐type glaciers (10 confirmed, 3 likely, and 5 possible) which accounted for 63% of the total area in the WKM. Furthermore, non‐surge‐type glaciers experienced little changes in recent decades, while surge‐type glaciers showed large ice loss. The existence of surge‐type glaciers may affect the assessment of glacier change in this region. The surge‐type glacier inventory of the West Kunlun Mountains was updated to include 10 confirmed, 3 likely and 5 possible typesSurge‐type glaciers changed markedly during 1970–2020, while non‐surge‐type glaciers were relatively stable in the West Kunlun MountainsAfter accelerating in velocity for 3–4 years, the surge‐type glacier frontal positions underwent advance The surge‐type glacier inventory of the West Kunlun Mountains was updated to include 10 confirmed, 3 likely and 5 possible types Surge‐type glaciers changed markedly during 1970–2020, while non‐surge‐type glaciers were relatively stable in the West Kunlun Mountains After accelerating in velocity for 3–4 years, the surge‐type glacier frontal positions underwent advance

Here we report our recent magnetic fabric investigation of loess deposition in Shagou section, located at the northeastern Qilian Mountains, the northeastern rim of the Tibetan Plateau. On the basis of environmental magnetism data, we indicate that the variation of anisotropy of magnetic susceptibility (AMS) parameters, especially the foliation (F) and degree of anisotropy (P), might be more sensitive to the environmental change in the arid and semiarid regions than the magnetic susceptibility fluctuation. During the investigated interval, from 0.83 to 0.128 Ma, most of the middle to late Pleistocene significant climate change can be unraveled by the AMS parameters, such as the strengthening of cold/dry climate, the step drying event occurred nearly 250 ka, and the severe environmental change in MIS16. Our results also suggest that there is strong correlation between median diameter (Md) of grain size, F, and P. We propose that the AMS parameters can act as an important paleoenvironmental change indicator in the arid and semiarid regions.

Much has been learned regarding orbital and millennial timescale climate changes after the onset of Northern Hemisphere glaciations (NHG) at ca. 2.7 Ma. By contrast, little is known about these variations before the NHG due to lack of high‐resolution records. Here we report first millennial resolution quantified East Asian summer monsoon (EASM) precipitation record from the north eastern Tibetan Plateau. The record supports astronomical forcing of EASM during the late Miocene, except for the period of 8.13–8.03 Ma when EASM experienced high amplitude variations at the 100‐, 20‐kyr, and suborbital bands, which is in sharp contrast with the damped astronomical forcing. Detection of strong 100‐kyr and millennial cycles during low eccentricity intervals of the warm late Miocene with ephemeral NH ice sheets cast doubt on NH ice sheet size variations as their exclusive forcing in the late Miocene and late Quaternary paleoclimatic records. Millennial and 100‐kyr cycles in paleoclimate records are normally attributed to Northern Hemisphere ice sheet size variations. Here we present the first 1‐kyr resolution quantitative East Asian summer monsoon precipitation record from the northeastern Tibetan Plateau during the late Miocene, when Northern Hemisphere ice sheets were ephemeral. The record demonstrates strong 100‐kyr and clear millennial cycles. Detection of 100‐kyr and millennial cycles in this warm time interval cast doubt on Northern Hemisphere ice sheet size variations as their exclusive forcing in paleoclimatic records. First 1‐kyr resolution quantitative northern China precipitation record during the late MioceneThe record reveals strong 100‐kyr and clear millennial cyclesDetection of 100‐kyr and millennial cycles in this warm interval challenges Northern Hemisphere (NH) ice sheet size variations as their exclusive forcing First 1‐kyr resolution quantitative northern China precipitation record during the late Miocene The record reveals strong 100‐kyr and clear millennial cycles Detection of 100‐kyr and millennial cycles in this warm interval challenges Northern Hemisphere (NH) ice sheet size variations as their exclusive forcing

Understanding the evolution of river systems in southern Africa is fundamental to constrain the evolution of landscape and sediment dispersal patterns. It is widely considered that the upper Zambezi River was connected with the Limpopo River during the Cretaceous, forming what was then the largest river in Africa. Crustal flexure during the Paleogene severed the upper Zambezi drainage from the Limpopo, setting the framework of the modern Zambezi and Limpopo River systems. We present first evidence—based on heavy‐mineral assemblages from cores drilled offshore of the Limpopo River mouth and samples collected in different reaches of the modern Limpopo River, integrated with magnetic susceptibility, detrital‐zircon geochronology, and geomorphological analysis—suggesting that the current Limpopo River formed recently in the Plio‐Quaternary. Plio‐Quaternary climate change is envisaged to have controlled the recent dynamics of river drainage and consequent distribution of sediment loads, as observed in many other transcontinental rivers worldwide. Landscape evolution, sediment dispersal patterns, and the accumulation of hydrocarbon and mineral resources in southern Africa, were largely determined by the evolution of the vast Zambezi‐Limpopo River system. It is widely believed that this river system attained its current configuration during the late Paleogene as a consequence of mantle‐driven dynamic uplift. Based on heavy‐mineral assemblages from river sediments and an International Ocean Discovery Program ocean core, we argue here instead for a Plio‐Pleistocene age for the formation of the modern characteristics of the Limpopo River (i.e., tens of millions of years younger than previously thought). This challenges the current paradigm on both formation modality and driving mechanisms of this vast river system. Plio‐Pleistocene climate change is envisaged to have controlled the dynamics of river drainage and consequent distribution of sediment loads, as observed in several other transcontinental rivers worldwide, underscoring the importance of these climate changes in driving river evolution world‐wide. The modern Limpopo River of South Africa formed in the Plio‐PleistocenePlio‐Pleistocene drainage reorganization was driven by climate changeFormation age and driving mechanisms of South African rivers are revisited The modern Limpopo River of South Africa formed in the Plio‐Pleistocene Plio‐Pleistocene drainage reorganization was driven by climate change Formation age and driving mechanisms of South African rivers are revisited

Various kinematic models have been proposed to explain the growth process of wide compressive orogens, and the deformation rate within the entire range of the orogen (rather than that of the leading‐edge fault) provides valuable information for model evaluation. Within the Qilian Orogen, between the central and northern Qilian Shan mountain in China, we studied the deformation of a series of Quaternary fluvial terraces across the North Tuolai Shan Fault (NTF), including optically stimulated luminescence dating of terrace ages. The results show that the six levels of terraces (T6 to T1) were formed at 58.4 ± 4.4 ka, 53 ± 5 ka, 46 ± 5 ka, 38 ± 5 ka, 23.2 ± 1.8 ka, and 4.8 ± 0.4 ka, respectively. Field investigations revealed that these terrace surfaces are faulted and folded by the NTF. Based on the deformation and ages of the terraces across the fault, the vertical slip rate is estimated as 1.5 ± 0.1 mm/yr, and the shortening rate is 0.9 ± 0.1 mm/yr, with a fault dip of 58°–60°. This deformation rate is similar to rates determined along the leading‐edge fault in the northern Qilian Shan and along the fault in the southern Qilian Shan. The widely distributed shortening across the ∼300‐km‐wide Qilian Orogen supports the kinematics of distributed upper crustal shortening across the Qilian Orogen, with a ductile lower crust, rather than a large, gradually propagating crustal‐scale deformation wedge. The shortening rate across the North Tuolai Shan Fault is estimated as 0.9 mm/yr, based on optically stimulated luminescence dating of fluvial terracesThe shortening rate within the ∼300 km Qilian Orogen suggests that crustal shortening is widely distributed along several thrust beltsThe distributed shortening supports the kinematics of a distributed upper crustal shortening across the orogen, with a ductile lower crust The shortening rate across the North Tuolai Shan Fault is estimated as 0.9 mm/yr, based on optically stimulated luminescence dating of fluvial terraces The shortening rate within the ∼300 km Qilian Orogen suggests that crustal shortening is widely distributed along several thrust belts The distributed shortening supports the kinematics of a distributed upper crustal shortening across the orogen, with a ductile lower crust