Search

Limiting excess atmospheric ammonia (NH3) is one of the great challenges for humanity in the 21st century but can only be achieved with adequate monitoring means in place. Here, we report the first NH3 measurements from the Geostationary Interferometric Infrared Sounder (GIIRS) onboard the Chinese FY‐4A satellite. The instrument scans almost all of Asia 10 times per day. We show that GIIRS′ unprecedented temporal sampling can be exploited to measure diurnal and nocturnal variations of NH3 and demonstrate this on two case studies over Punjab and the North China Plain. Day–night variations are found to be almost absent in winter, but can reach a factor 2–3 in the warmer months. These case studies are very promising given the future landscape of geostationary sounders, but also show that improved knowledge on lower tropospheric air temperatures and the vertical profile of NH3 is key to better exploit their measurements. Plain Language Summary: To reduce the worldwide concentrations of ammonia (NH3) in the air is one of the great challenges for humanity in the 21st century, but this can only be achieved with stringent policies in place, and with the support of accurate and frequent measurements. In this paper, we report the first ammonia measurements from the Geostationary Interferometric Infrared Sounder (GIIRS) onboard the Chinese FY‐4A satellite. The satellite is positioned above Indonesia and measures almost all of Asia 10 times per day. We show that GIIRS' measurements can be used to measure ammonia both during day and night. We look into more detail at two locations, over Punjab (Pakistan) and the North China Plain. Day‐night variations are found to be almost absent in the colder months, but can reach a factor 2–3 in the warmer months. These case studies are very promising given the future landscape of geostationary sounders, but demonstrate also that improved knowledge on the air temperature at the surface and the behavior of ammonia at higher altitudes will result in more accurate ammonia measurements. Key Points: We report the first observations of atmospheric NH3 from the geostationary satellite FY‐4A GIIRS over AsiaThe potential of GIIRS to reveal the diurnal and nocturnal variations of NH3 total columns is demonstrated over two sitesTo better exploit geostationary data, improved temperature profiles and knowledge on the vertical NH3 distribution is needed [ABSTRACT FROM AUTHOR]

Monsoon onset over the South China Sea occurs in April–May, marking the start of the wet season over East Asia. Skillful prediction of onset timing remains an open challenge. Recently, theoretical studies using idealized models have revealed feedbacks at work during the seasonal transitions of the Hadley cells and have shown that these are relevant to monsoon onset over Asia. Here, I hypothesize that monsoon onset occurs earlier in years when the atmosphere over the South China Sea is already in a state where these feedbacks are more easily triggered. I find that local anomalies in lower‐level moist static energy in the preceding January–March are well correlated with South China Sea Monsoon onset timing. This relationship remains relatively consistent on decadal timescales, while correlations with other teleconnections vary, and is used to develop a simple forecast model for onset timing that shows skill competitive with that of more complex models. Plain Language Summary: Arable land in China is estimated to feed 20% of the world's population on 7% of the world's farmlands, with much of this region watered by rainfall from the East Asian Summer Monsoon. Forecasting the arrival of the monsoon, which occurs first over the South China Sea in April–May, is therefore helpful for agricultural planning. However, producing a reliable forecast remains an open challenge. Recently, simple climate models, for example, models including seasons but with no land, have been used along with observations to investigate the most basic processes controlling climatological monsoon onset over Asia. In this paper, I suggest that year‐to‐year variations in monsoon onset timing are controlled by the same processes and, based on these, I suggest climate variables that may help in predicting when the monsoon will begin. By using this approach, I find that the "Moist Static Energy" (a quantity that combines temperature and humidity) over the South China Sea in January–March is strongly correlated with monsoon onset timing. This insight can be used to predict future onset timing competitively compared with more complex forecast models. Key Points: Recent theoretical studies have revealed feedbacks at work during monsoon onsetIf the spring atmosphere is in a state where these feedbacks are easily triggered, onset is earlierThis insight is used to produce a simple forecast of South China Sea Monsoon onset timing [ABSTRACT FROM AUTHOR]

Crustal deformation and hydrothermal percolation related to the India‐Asia collision have caused extensive remagnetization of the Tethyan Himalaya Terrane (THT). The present work identified three phases of regional remagnetization during 62.3–50.0 Ma for the east‐central THT. Consequently, a model of three‐stage India‐Asia collision was proposed. The east‐central THT first collided with the southward migrated southern margin of the Lhasa Terrane (LT) at 5.4 ± 0.9°N during 62.3–60.9 Ma. Subsequently, the THT continuously moved northward and pushed the southern margin of the LT back to its original position prior to the initiation of fore‐arc and back‐arc extension on both sides of the Gangdese magmatic arc. Since the final suturing of the THT with Asia at ∼10°N during 59.8–58.0 Ma, the east‐central THT remained stationary until India collided with it at 10.9 ± 5.1°N at ∼50.0 Ma. Plain Language Summary: The collision of India and Asia caused intense tectonic deformation and hydrothermal alteration throughout the Tethyan Himalaya Terrane (THT), which resulted in the large‐scale remagnetization in the THT. The regional remagnetization of the THT can be used to constrain the India‐Asia collision process, on the premise that the time of remagnetization can be determined. Based on this assumption, we measured two representative Paleocene remagnetized components from Early Jurassic limestones in the Gyangze Basin in the east‐central THT. These remagnetized components, combined with non‐remagnetized components and remagnetization events recorded in the adjacent areas, suggest that the east‐central THT experienced three phases of regional remagnetization during 62.3–50.0 Ma. The first and second phases of remagnetization in the north‐central part of the east‐central THT occurred at the paleolatitude of 5.4 ± 0.9°N at 62.3–60.9 Ma and 10.3 ± 1.0°N–9.5 ± 1.1°N at 59.8–58.0 Ma, respectively. The third phase of remagnetization occurred in the southern part of the east‐central THT, at the paleolatitude of 10.9 ± 5.1°N at ∼50.0 Ma. Consequently, a model of three‐stage India‐Asia collision and southward spreading tectonic deformation of the THT was proposed based on these successive remagnetizations. Key Points: The east‐central Tethyan Himalaya Terrane (THT) experienced three phases of large‐scale remagnetization during 62.3–50.0 MaThe collision of THT with the Lhasa Terrane commenced at 62.3–60.9 Ma and finished at 59.8–58.5 MaIndia finally collided with the THT at the paleolatitude of ∼10.9 ± 5.1°N at ∼50.0 Ma [ABSTRACT FROM AUTHOR]

A growing body of research has underscored the radiative impact of mineral dust in influencing Indian summer monsoon rainfall variability. However, the various aerosol‐cloud‐precipitation interaction mechanisms remain poorly understood. Here we analyze multisatellite observations to examine dust‐induced modification in ice clouds and precipitation susceptibility. We show contrasting dust‐induced changes in ice cloud regimes wherein despite a 25% reduction in ice particle radius in thin ice clouds, we find ~40% increase in ice particle radius and ice water path in thick ice clouds resulting in the cloud deepening and subsequently strengthened precipitation susceptibility, under strong updraft regimes. The observed dust‐ice cloud‐precipitation interactions are supported by a strong correlation between the interannual monsoon rainfall variability and dust frequency. This microphysical‐dynamical coupling appears to provide negative feedback to aerosol‐cloud interactions, which acts to buffer enhanced aerosol wet scavenging. Our results underscore the importance of incorporating meteorological regime‐dependent dust‐ice cloud‐precipitation interactions in climate simulations. Plain Language Summary: The Indian summer monsoon is the central source of freshwater availability to the densely populated regions of southern Asia. The monsoon circulation and rainfall variability are widely known to be governed by large‐scale atmosphere‐land‐ocean dynamics, meteorological processes, and air‐sea interactions. In the past two decades, the role of atmospheric aerosols has emerged as a source of modulating monsoon rainfall, as suggested by a host of climate modeling studies. In this paper, we have investigated a new aspect of aerosols in possibly influencing monsoon clouds and rainfall by specifically examining interaction between mineral dust aerosols and ice clouds, as part of the monsoon system. Using state‐of‐the‐art information derived for aerosols and clouds from multisensor and disparate satellite observations spanning 11 years, we find characteristic signature of dust aerosol‐induced modification of thick ice clouds (so‐called cloud invigoration effect) toward strengthened susceptibility of monsoon precipitation. Overall, our results shed new light on the potential role of dust and ice cloud interactions in modulating the Indian summer monsoon. Key Points: Elevated dust‐induced microphysical‐dynamical coupling in thick ice clouds amplifies ice cloud formation under favorable meteorologyStrengthened summer monsoon precipitation susceptibility is linked to dust‐induced changes in ice clouds under strong updraft regimesMicrophysical‐dynamical coupling provides negative feedback to aerosol‐cloud interaction and buffers the enhanced aerosol wet scavenging [ABSTRACT FROM AUTHOR]

El Niño/Southern Oscillation (ENSO) is the main climate mode that drives the interannual variability in climate and consequently vegetation greenness. While widespread green‐up has been reported and examined in tropical America during El Niño, it remains unclear how vegetation in tropical Asia changes during the period. Here, we used four remote sensing‐based leaf area index (LAI) products to investigate changes in vegetation greenness during the 2015/16 El Niño in tropical Asia. We found a strong green‐up during the 2015/16 El Niño in tropical Asia, with its regional average LAI stronger than that of tropical America. The drivers for the green‐up vary across the region, with radiation being the main driver for continental tropical Asia, and temperature and soil water anomalies in the west and east parts of maritime tropical Asia, respectively. These findings provide important insights into the response of tropical Asia's vegetation to extreme climate anomalies. Plain Language Summary: El Niño is a climate pattern that is associated with warm and dry conditions in tropical forest regions. Significant climatic changes during El Niño thus affect vegetation greenness (i.e., growth, size of canopy, amount of leaves). While an increase in vegetation greenness has been reported in tropical America during El Niño, it remains unclear how vegetation in tropical Asia changes during the period. Here, we used satellite data to investigate changes in vegetation greenness during El Niño in 2015–2016 in tropical Asia. We found a strong increase in vegetation greenness in tropical Asia during this period. The cause of this increase in greenness varied across different parts of tropical Asia. In mainland tropical Asia, sunlight was the main driver, while in maritime Southeast Asia, temperature or soil moisture was the main driver. These findings help provide better understanding of how vegetation in tropical Asia responds to extreme climate events like El Niño. Key Points: Tropical Asia experienced strong green‐up during the 2015/16 El Niño, stronger than that of tropical AmericaIn continental tropical Asia, green‐up was mostly driven by anomalously high shortwave radiationIn maritime tropical Asia, green‐up was primarily driven either by anomalously warmer temperatures or drier soil moisture from the west to east [ABSTRACT FROM AUTHOR]

Whether tectonic strain from the early stage India‐Asia collision has synchronously affected the far‐field margin of the Tibetan Plateau is crucial for understanding plateau deformation and growth processes. However, direct evidence for early far‐field deformation remains scarce. Utilizing illite K‐Ar dating of three fault gouge samples, we established the faulting history of the Leibo fault zone (LFZ) at the southeastern margin of the Tibetan Plateau (SEMTP). Consistent authigenic illite ages of 52 ± 2, 54 ± 12 and 55 ± 6 Ma suggest the reactivated thrust faulting of the LFZ in the Early Cenozoic. Positioned ∼700 km east of the collisional boundary and at the intersection of three blocks with distinct lithospheric rheology in strength/viscosity, this event suggests a quasi‐synchronous far‐field tectonic response in the SEMTP to the India‐Asia collision. Plain Language Summary: Understanding how tectonic strain resulting from the collision between the Indian and Eurasian plates in the Early Cenozoic can spread to the edges of the Tibetan Plateau is crucial for comprehending the plateau's tectonic development. To investigate this question, we used fault gouge, which resulted from the sliding of brittle faults, to directly reveal faulting information. By conducting illite K‐Ar dating on three samples from the Leibo fault zone (LFZ) at the southeastern margin of the Tibetan Plateau (SEMTP), we found consistent ages of newly formed illite, 52 ± 2, 54 ± 12, and 55 ± 6 million years ago. Since this type of minerals form simultaneously with faulting, these ages reveal a reactivated thrust faulting event of the LFZ, suggesting a nearly simultaneous response of faulting in the SEMTP to the early stage of the India‐Asia collision. Key Points: Fault gouge illite K‐Ar dating is used to establish the faulting history of the Leibo fault zone, SE margin of the Tibetan PlateauThree consistent authigenic illite ages of ∼55, ∼54, and ∼52 Ma suggest a reactivated thrust faulting event of the Leibo fault zoneThis event indicates a quasi‐synchronous far‐field response of the SE margin of the Tibetan Plateau to the India‐Asia collision [ABSTRACT FROM AUTHOR]

Global warming is expected to have far‐reaching impacts on the frequency and intensity of extreme events, but the effects of anthropogenic warming on the emergence seasons of year‐maximum near‐surface wind speed (NSWS) remain poorly understood. We provide a comprehensive map of the changing emergence seasons of year‐maximum NSWS using Coupled Model Intercomparison Project Phase 6 projections. Our analysis reveals a rapid response of synoptic‐scale extreme NSWS to global warming, with consistent spatial patterns observed across various periods and warming scenarios. The most significant increase (∼16%) in the emergence season is projected to occur in December‐January‐February (DJF) over Mid‐high‐latitude Asia by the end of the 21st century. The study also anticipates changes in the emergence seasons of year‐maximum NSWS at a regional scale. These results deepen our understanding of the complex and interconnected nature of global climate change and underscore the need for concerted efforts in addressing this pressing challenge. Plain Language Summary: Global warming is indisputably triggering changes in the world's weather systems, leading to more frequent and intense extreme weather events. However, it is unclear how anthropogenic warming affects the timing of the annual strongest near‐surface wind speed (NSWS). In this study, we used state‐of‐the‐art global climate models to create a comprehensive map illustrating these NSWS patterns of response to global warming. We discovered that these changes are consistent across various time periods (near to long term) and warming scenarios (low to high warming), revealing a robust relationship between extreme NSWS and global warming. The most significant change is observed during December‐January‐February in Mid‐high‐latitude Asia, with an increase of about 16% by the end of the 21st century. Our findings suggest that we can expect more year‐maximum NSWS occurs in different regions during specific seasons: December‐January‐February in North America and Asia, March‐April‐May in Africa, June‐July‐August in Asia and West Africa, and September‐October‐November in South America and Australia. These results offer valuable insights for guiding adaptation efforts even if ambitious climate actions manage to limit global warming at a lower level. Key Points: Changing emergence seasons of the land year‐maximum near‐surface wind speed (NSWS) map is createdThere is a rapid response of emergence seasons of year‐maximum NSWS to anthropogenic warmingThe strongest increase (16%) in emergence season is projected to occur in December‐January‐February over Mid‐high‐latitude Asia [ABSTRACT FROM AUTHOR]

A relation between tectonics and arc magmatism has been proposed in the west Pacific‐type accretionary orogens, but the specific mechanism remains unclear. This study examines the Cretaceous records in NE Asia in order to unravel this link. Two tectono‐magmatic episodes, namely the Early and Late Cretaceous, are recognized. The first episode was under (trans‐)extension, consisting of both mafic and felsic, depleted and enriched, and deep‐ and shallow‐derived arc magmas. The second episode experienced several compressive events with highly evolved and shallow‐derived (mid‐crustal level) arc magmas. We propose that (trans‐)extension thinned the arc crust, facilitating deep mafic magmas to ascend and cool rapidly, maintaining their geochemical diversity. Compression led to magmatic emplacement around the middle crust; and the warm crust allowed highly‐evolved granitoids to form. Therefore, tectonic setting controls arc magmatism in NE Asia, and is likely representative of other west Pacific‐type orogens. Plain Language Summary: Arc magmas are produced where oceanic plates subduct into the mantle. Their chemical composition varies in different tectonic settings, but the specific mechanism is unclear. We explore this question using the NE Asian setting during the Cretaceous. Here, the Early Cretaceous arc magmas reveal diverse compositions when in a setting undergoing extension. However, the Late Cretaceous magmas uniformly contain high silica contents when the continental crust was under compression. This implies that thin arc crust under extension facilitated the ascent of deeply‐derived magmas and these cooled rapidly and kept their chemical diversity. In contrast, crust under compression prohibited the ascent of deep magmas, instead inducing crustal melting and slower cooling in the middle crust, thus increasing the silica content. Therefore, tectonics strongly affected the nature of arc magmatism in NE Asia, and possibly other west Pacific‐type orogens. Key Points: Cretaceous magmatism in the NE Asian arcs was diverse during extension, but highly evolved under compressionExtension induced deep magmas to ascend and cool rapidly; Compression restrained deep magmas and extended coolingArc magmas were controlled by alternating extensional and compressional regimes during subduction retreat in west Pacific‐type orogens [ABSTRACT FROM AUTHOR]

Whether the South Asian summer monsoon (SASM) is controlled by local or remote insolation at the orbital band remains uncertain. Here, we perform a transient simulation forced by Earth's orbital parameters between 400 and 350 ka BP, a period characterized by significant contrast between local and remote insolation, to identify the SASM's response to insolation forcing. Simulation results suggest that the primary driver of orbital‐scale SASM variability is the Northern Hemisphere high‐latitude June insolation, as opposed to local insolation. High June insolation in the Southern Hemisphere might reduce the SASM intensity. Remote insolation influences the SASM by altering the latitudinal thermal gradient and, consequently, the meridional position of the South Asian high (SAH). The SAH is associated with intense convection and hence drives the meridional shift of the intertropical convergence zone and the SASM rain belt. Thus, orbital‐scale SASM variability is strongly related to remote insolation forcing. Plain Language Summary: Because the monsoon is directly related to the movement of the subsolar point, insolation changes are important in regulating the South Asian summer monsoon (SASM) intensity at an orbital timescale. However, it remains unclear whether the SASM is driven by local insolation that directly strikes southern Asia, or remote insolation in the high‐latitude Northern Hemisphere or the Southern Hemisphere at the precession band. We find a time window between 400 and 350 ka BP (ka = thousand years, BP = before present) when local and remote insolations differ significantly, allowing us to determine which insolation dominates the SASM at orbital timescales. We use an Earth system model with orbital forcing to run a transient simulation between 400 and 350 ka BP. Simulations suggest that the SASM is primarily influenced by Northern Hemisphere high‐latitude summer insolation rather than local insolation. Additionally, Southern Hemisphere insolation has a negative impact on orbital‐scale SASM variability. Remote insolation influences the SASM by inducing an anomalous meridional thermal gradient, which moves the South Asian high and thus the Intertropical Convergence Zone. Our findings are significant for future SASM projections because the obvious difference between remote and local insolation will reappear in the next 50 ka. Key Points: Local insolation is not the direct driver for orbital‐scale variability of the South Asian summer monsoon (SASM)The meridional shift of the South Asian high (SAH) affects orbital‐scale SASM variabilityRemote insolation influences the meridional shift in the SAH through altering the latitudinal thermal contrast [ABSTRACT FROM AUTHOR]

Although the multi‐model average compares well with observations, individually most of the latest climate models do not simulate a realistic size of the Indo‐Pacific Warm Pool in the present‐day climate. This study explores the implications of this warm pool size bias in climate models in Northern Hemisphere winter. The warm pool size bias in phase 6 of the Coupled Model Intercomparison Project models is related to the subtropical jet and precipitation distribution, both in the present‐day climate and in response to climate change, through extratropical Rossby wave trains and tropical circulation pathways. Based on these relationships, emergent constraints are developed to observationally constrain the future subtropical jet response over Asia and the Atlantic Ocean and precipitation response over North and Central America, which can help to reduce uncertainty in future projections of these features. Thus, accurate model simulation of the warm pool in the present‐day climate is important for future projections of the subtropical jet and precipitation. Plain Language Summary: This study examines the impact of a common problem in the latest climate models where they do not accurately simulate the size of the Indo‐Pacific Warm Pool in the present‐day climate. The effects of this issue are investigated in the Northern Hemisphere winter. The warm pool size problem in the models affects the subtropical winds and precipitation, both in the current climate and in response to climate change. Based on the relationships between the present‐day warm pool size and future projections of the subtropical winds and precipitation across models, we can help to constrain future projections of the subtropical winds over Asia and precipitation over North and Central America by ruling out models with biased warm pool size. The results show that having an accurate simulation of the warm pool in the present‐day climate is crucial for more reliable future projections of subtropical winds and precipitation. Key Points: Phase 6 of the Coupled Model Intercomparison Project multi‐model‐mean reproduces the observed Indo‐Pacific warm pool size well, but there is a huge inter‐model spread in warm pool sizeModel biases in warm pool size have local and remote effects on subtropical winds and precipitation in present‐day and future climatesEmergent constraints reduce projection uncertainty of subtropical winds and precipitation by ruling out models with biased warm pool size [ABSTRACT FROM AUTHOR]

Gravitational‐wave high‐energy Electromagnetic Counterpart All‐sky Monitor (GECAM) is a space‐borne instrument dedicated to monitoring high‐energy transients, including Terrestrial Gamma‐ray Flashes (TGFs) and Terrestrial Electron Beams (TEBs). We implemented a TGF/TEB search algorithm for GECAM, with which 147 bright TGFs, 2 typical TEBs and 2 special TEB‐like events are identified during an effective observation time of ∼9 months. We show that, with gamma‐ray and charged particle detectors, GECAM can effectively identify and distinguish TGFs and TEBs, and measure their temporal and spectral properties in detail. A very high TGF‐lightning association rate of ∼80% is obtained between GECAM and GLD360 in east Asia region. Plain Language Summary: Terrestrial gamma‐ray flashes (TGFs) and Terrestrial Electron Beams (TEBs) represent the most energetic radioactive phenomena in the atmosphere of the Earth. They reflect a natural particle accelerator that can boost electrons up to at least several tens of mega electron volts and produce gamma‐ray radiation. With novel detection technologies, Gravitational‐wave high‐energy Electromagnetic Counterpart All‐sky Monitor (GECAM) is a new powerful instrument to observe TGFs and TEBs, as well as study their properties. For example, it is difficult for most space‐borne high‐energy instruments to distinguish between TGFs and TEBs. However, we show here that, with the joint observation of gamma‐ray and charged particle detectors, GECAM can effectively identify TGFs and TEBs. GECAM can also reveal their fine features in the light curves and spectra. Key Points: During 9‐month observation, Gravitational‐wave high‐energy Electromagnetic Counterpart All‐sky Monitor (GECAM) has detected 147 bright Terrestrial Gamma‐ray Flashes (TGFs), 2 typical Terrestrial Electron Beams (TEBs), and 2 special TEB‐like eventsWith novel detector design, GECAM can effectively classify TGFs and TEBs, and reveal their fine temporal featuresWe obtained a very high TGF‐lightning association rate (∼80%) between GECAM and GLD360 in east Asia region [ABSTRACT FROM AUTHOR]

Dust deposition in northeastern Asia since the Last Glacial Maximum has previously been studied using a variety of archives. However, the mechanisms driving variability in dust are less well constrained. Here, we present records of the Nd‐Sr isotope and major element composition of sediments from Lake Tuofengling, a crater lake located in northeastern China, over the past ∼25 thousand years. The results indicate that the lithogenic fractions of the sediments are a mixture between aeolian dust and local volcanic detritus. Our provenance data suggest that the aeolian dust component is predominantly from the Mongolia Plateau, likely carried by the East Asian Winter Monsoon. Our isotope and calculated dust flux records exhibit similar changing patterns to proxies of global ice volume and the strength of Atlantic meridional overturning circulation, potentially implicating ice sheets and ocean circulation as the dominant drivers of the East Asian Winter Monsoon over this time interval. Plain Language Summary: Dust storms occur frequently throughout Central and East Asia today. Several driving factors, particularly related to the East Asian Summer Monsoon, the East Asian Winter Monsoon (EAWM), and the westerlies, can influence dust production and transport in these regions, both in the modern and during the past. Uncovering the dominant factor(s) can assist in furthering our understanding of atmospheric circulation over Asia during climates both similar and different from today. Here, we collected sediments from a crater lake (Lake Tuofengling (TFL)) located in northeastern Asia and reconstructed dust inputs over the past 25 thousand years. We found that the dust delivered to TFL sediments is mainly sourced from the Mongolian Plateau associated with transport via winds related to the EAWM. Further in‐depth analysis indicates that shifts in ice volume and Atlantic Ocean circulation may be important drivers for the EAWM, at least over the past 25 thousand years. Key Points: Geochemical evidence suggests that the Mongolian Plateau (MP) is the main source of dust for Lake Tuofengling (TFL)The East Asian Winter Monsoon (EAWM) is likely the dominant carrier of aeolian dust from the MP to TFLDust flux and EAWM variability could be driven by a combination of changes in ice volume and Atlantic Ocean circulation [ABSTRACT FROM AUTHOR]

Past ground surface temperature (GST), one of the important aspects of paleoclimate reconstructions, can be inverted from borehole temperature measurements. Here, we report continuous 6,100‐m temperature logs in the International Continental Scientific Drilling Program SK‐2e. We inverted the past GST changes from upper borehole temperature logging (<600 m). Below this depth, localized fluid flow masks the paleoclimate record. Inversions yield an approximately 2 K GST rise since 0.1–0.6 Kyr BP and an approximately 10 K rise since 20 Kyr BP. Assuming a ±5 K influence from the deep groundwater flow, the inverted temperature rise has varied between 8 and 12 K since 20 Kyr BP, which is consistent with previous reports since the Last Glacial Maximum. Our results emphasize the potential of borehole heat‐flow profiles as a record of climate changes and the importance of climate correction for heat‐flow determinations. Plain Language Summary: Temperatures within the shallow boreholes are perturbed by changes in ground surface temperature (GST) in response to paleoclimate variations and anthropogenic land use. The GST varies at different time scales, and these variations penetrate different depths underground. Thus, the borehole temperatures can be used for reconstructing the history of ground surface temperatures. Based on borehole geotherms of the International Continental Scientific Drilling Program in Northeast Asia, the past GST changes since the Last Glacial Maximum were inverted. The results show a ∼2 K surface temperature rise during 0.1–0.6 Kyr BP and a ∼10 K rise since 20 Kyr BP, which is consistent with previous independent estimates. Key Points: We report an undisturbed 6,100‐m continuous heat‐flow profile from the scientific drilling project SK‐2eThe heat‐flow profile recorded a 2 K rise of ground surface temperature in the last five centuries and a 10 K rise since the Last Glacial MaximumA basin‐scale comparison reveals localized heat‐flow anomalies induced by advective heat in deep and confined high‐permeability aquifers [ABSTRACT FROM AUTHOR]

Deciphering dust outbreak frequency in inland Asia during the late Cenozoic is important for predicting future hydroclimate in the arid parts of China. Here, we present an eolian sedimentary sequence in the southern Junggar Basin over the past 3.5 Ma, Northwestern China. Our data provide a minimum age of 3.5 Ma for the Gurbantunggut Desert. Rb/Sr ratios exhibit prominent 405 Kyr eccentricity cycles throughout our record with weak expression 41 Kyr cycles. We interpret this cyclicity as resulting from a strong impact of the global carbon cycle on western China hydroclimate. By contrast, gamma‐ray intensity data displays significant 100‐ and 41‐Kyr cycles after 2.8 Ma, suggesting important variations of the input of westerly derived dust. Our results demonstrate that Westerly derived moisture supply and dust input into inland Asia respond differently to orbital forcing; they suggest that moisture supply and dust transport by the Westerlies are controlled by different drivers since 3.5 Ma. Plain Language Summary: Little is known about how hydrological changes in desert areas respond to today's high atmospheric CO2 concentrations. Hydroclimatic archives from these areas are critical to understand (and possibly forecast) future hydrological changes at local and regional scales. Herein, we present paleomagnetic, gamma‐ray intensity and Rb/Sr data over the past 3.5 Ma from an eolian sedimentary sequence in the southern Junggar Basin, Northwestern China. Our results provide a minimum age of 3.5 Ma for the Gurbantunggut Desert; they show that humidity and Westerlies strength variations in inland Asia follow different cyclicity during the Quaternary, indicating that moisture supply by the Westerlies since 3.5 Ma is not directly impacted by wind strength. Our results show that Junggar hydroclimate is likely poorly sensitive to changes in Westerlies strength, despite their role as moisture conveyor, raising questions about the main control on moisture supply in inland Asia. Key Points: Rb/Sr ratios exhibit prominent 405 Kyr eccentricity cycles throughout our recordGR data displays significant 100‐ and 41‐Kyr cycles after 2.8 MaMoisture supply by westerlies is not directly impacted by wind strength since at least 3.5 Ma [ABSTRACT FROM AUTHOR]

Emissions of air pollutants and their precursors in urban air closely relate to urbanization involving economic development, population growth, and industrialization. Here we use formaldehyde (HCHO) columns from the TROPOspheric Monitoring Instrument (TROPOMI), night‐time light (NTL) radiance from the Visible Infrared Imaging Radiometer Suite, and population density data as respective proxies to explore how anthropogenic non‐methane volatile organic compound (NMVOC) emissions evolve with urbanization in Asia. HCHO columns correlate moderately to highly (0.64 ≤ r ≤ 0.99) with the NTL radiance within most major Asian countries. On both national (across Asia) and provincial scales (within China), HCHO columns increase monotonically with NTL radiance or population density with a log‐linear pattern, implying anthropogenic NMVOC emissions in Asia may similarly respond to urbanization with no apparent turnover yet. Our study confirms TROPOMI HCHO columns as a proxy of anthropogenic NMVOC emissions. Plain Language Summary: We use multi‐source satellite remote sensing data and population density data to examine how anthropogenic non‐methane volatile organic compound (NMVOC) emissions evolve with urbanization in Asia. Anthropogenic NMVOC emissions (indicated by satellite formaldehyde columns) correlate moderately to highly with urbanization (indicated by night‐time light or population density) within most major Asian countries. We find a monotonic response between anthropogenic NMVOC emissions and urbanization in Asia, with no apparent turnover yet. Key Points: Satellite formaldehyde (HCHO) columns correlate moderately to highly with night‐time light radiance and population density in most major Asian countriesA monotonic response between anthropogenic non‐methane volatile organic compound (NMVOC) emissions and urbanization may exist in Asia, with no apparent turnover yetTROPOspheric Monitoring Instrument HCHO column is confirmed as a reliable proxy of anthropogenic NMVOC emissions in Asia [ABSTRACT FROM AUTHOR]

The extension of back‐arc basins and formation of marginal seas following the subduction of oceanic lithosphere are usually attributed to the rollback of subducting slabs and distorted mantle convection. However, for the Japan Sea, the largest marginal sea in the northwestern Pacific, its opening is unlikely only resulted from the subduction of the Pacific plate because of the coeval Philippine plate subduction and the arcuate arc volcanic zone. Therefore, the present‐day thermal structure in the uppermost mantle, which can be directly constrained by strong Pn‐wave attenuation, plays a vital role in understanding the Japan Sea opening. Here, we observe two belts of strong Pn attenuation beneath the Japan Sea; their strikes are generally consistent with local Pn anisotropy and the retreat directions of the Pacific and Philippine trenches. Hence, there seem to be two divergent mantle flows in the uppermost mantle, pushing a "double door" for the Japan Sea opening. Plain Language Summary: The western Pacific is one of the most active regions of global tectonics. For the Japan Sea, the largest marginal sea in the northwest Pacific, its formation mechanism is still controversial. The Japan Sea may have experienced a complex evolution process driven by the superposition of multiple mechanisms, and finally produced a diamond‐shaped ocean. The present thermal structure in the uppermost mantle, which can be directly constrained by strong Pn‐wave attenuation, plays a vital role in understanding the Japan Sea opening. In this study, we construct a high‐resolution broadband Pn attenuation model for the uppermost mantle beneath the Japan Sea. Two strong Pn attenuation belts are observed in this region, with their strikes generally consistent with the local Pn velocity anisotropy and the opening directions of the Japan Sea. Therefore, two divergent mantle flows likely exist in the uppermost mantle, pushing the opening of the Japan Sea like a "double door." These mantle flows could be part of mantle convection in a big mantle wedge, where ascending hot materials from the deep mantle not only feed volcanoes in northeastern Asia but also thicken the back‐arc oceanic crust. Key Points: A high‐resolution broadband Pn attenuation model is obtained beneath the Japan SeaHot mantle materials ascend to feed the volcanoes in NE Asia, intruding into and thickening the oceanic crust in the Japan SeaDivergent mantle flows likely push the fan‐shaped rotational opening of the Japan Sea [ABSTRACT FROM AUTHOR]

We determine high‐resolution 3‐D tomographic images of P‐wave isotropic velocity, radial anisotropy and azimuthal anisotropy beneath NE Asia down to 800 km depth. Our results show negative radial anisotropy (i.e., Vhorizontal < Vvertical) in the asthenosphere of the big mantle wedge (BMW), which may reflect mineral alignment caused by vertical flow in the asthenosphere. Across the Tanlu fault zone (TLF), the western and eastern parts of the BMW exhibit high and low P‐wave velocities, respectively. Combining our tomographic results with surface geological features, we speculate that convection in the BMW includes upwelling asthenosphere beneath the Japan Sea and the Korean Peninsula and downwelling asthenosphere beneath the Songliao and North China basins. The downwelling asthenosphere beneath the two basins is associated with diminishing volcanism and anomalous tectonic subsidence since ∼110 Ma. The great TLF is an important boundary for the BMW structure and dynamics. Plain Language Summary: The subducting Pacific plate becomes flat in the lower part of the mantle transition zone beneath NE Asia, and a big mantle wedge (BMW) has formed above the flat slab. The BMW controls tectonic and geological activities in NE Asia, which are characterized by large‐scale sedimentary basins, lithospheric thinning, large strike‐slip faults, deep earthquakes and intraplate volcanism. However, the convection pattern in the BMW is still unclear. We determine the first 3‐D P‐wave radial anisotropy model down to 800 km depth beneath NE Asia, as well as high‐resolution tomographic images of isotropic P‐wave velocity and azimuthal anisotropy. We find predominant negative radial anisotropy in the BMW and east‐west variations of velocity structure. Combining the tomographic results with surface geological features, we speculate that convection in the BMW may include upwelling flows beneath the SW Japan Sea and the southern Korean Peninsula and downwelling flows beneath the Songliao and North China basins. Key Points: The first 3‐D radial anisotropy model beneath NE Asia is obtainedEast‐west structural variations in the big mantle wedge (BMW) are revealedA possible convection pattern in the BMW is proposed [ABSTRACT FROM AUTHOR]

Long‐distance lateral magma propagation may reflect the complex interaction between regional tectonics and crustal uplift. Here, we report observations on the Taxkorgan intrusive complex (TIC) of the Central Pamir. TIC is a 70 km long, 10–18 km wide, north‐northwest–elongated body intruded into mid‐upper crust in parallel with, and close to, the Kongur Shan Extensional System. New zircon U‐Pb dating shows that syenite samples exhibit a clear younging pattern from south to north along the pluton axis within an interval between 11.5 and 10.3 Ma, which is interpreted as lateral magma propagation from a single feeder zone at its northwestern margin. The lateral magma propagation was caused by a combination of crustal rigidity differences, and a topography‐induced pressure gradient that is nearly orthogonal to the least compressive stress. We propose that long‐distance lateral magma propagation plays an important role in plateau expansion, restraining the thickness and elevation of the Pamir Plateau. Plain Language Summary: Long‐distance lateral magma propagation within the crust has been documented for diverse magmatic systems. The Miocene Taxkorgan intrusive complex was formed during India‐Asia collision in the Central Pamir Plateau, and it consists of a syenite pluton and several discrete lobes of monzogranites. New SIMS zircon U‐Pb dating results shows that monzogranites across TIC have overlapping ages between 12.4 and 12.2 Ma, indicating they were emplaced from a series of synchronous and independent magma feeder zones. In contrast, syenite samples exhibit a clear younging pattern from south to north within an interval between 11.5 and 10.3 Ma. The pattern of decreasing ages along the pluton axis is interpreted as lateral magma propagation from a single feeder zone at its northwestern margin. It is inferred that long‐distance lateral magma propagation, such as documented for the Taxkorgan intrusive complex, played a key role in plateau expansion, restraining the thickness and elevation of the Pamir Plateau. Key Points: Taxkorgan intrusive complex (TIC) syenite pluton shows a clear younging pattern from south to north within an interval between 11.5 and 10.3 MaTIC syenite pluton formed by lateral magma propagation from a single feeder zone at its northwestern marginLong‐distance lateral magma propagation plays an important role in plateau expansion, restraining the thickness and elevation of Plateau [ABSTRACT FROM AUTHOR]

The Tibetan Plateau (TP) is important in shaping the global climate. To understand how its thermal condition may affect the Atlantic meridional overturning circulation (AMOC), we conduct a series of albedo forcing experiments to simulate the TP warming and cooling conditions. The results show that the TP warming can immediately generate anticyclone in the subtropical North Atlantic, leading to more water vapor transporting from the North Atlantic to eastern tropical Pacific. This results in less precipitation over the North Atlantic and increases the sea surface salinity. The latter enhances the deep‐water formation in the subpolar North Atlantic and thus the AMOC. In contrast, the TP cooling weakens the AMOC via opposite processes. These findings imply that the AMOC change can be affected not only by local factors but also remote forcing from Asia. Plain Language Summary: The Tibetan Plateau (TP) plays a vital role in regulating the regional and global climate. By far, most studies focus on the impacts of TP thermal effect on atmospheric change. Few efforts have been devoted to investigate the TP thermal effect on ocean circulation. In this study, we artificially reduce and increase the surface albedo over the TP region to simulate the TP warming and cooling conditions. The results show that the TP thermal conditions can affect the Atlantic meridional overturning circulation (AMOC) strength by altering the inter‐basin moisture transport between the North Atlantic and tropical Pacific. The TP heating immediately generates a westward Rossby wave train that can arrive at the North Atlantic, resulting in anomalous high‐pressure system over there. This helps to bring more moisture from the North Atlantic to eastern tropical Pacific. The moisture divergence over the North Atlantic increases the sea surface salinity, which is responsible for the enhanced deep‐water formation and thus the AMOC. In contrast, the TP cooling leads to AMOC weakening via opposite processes. Our study implies that the 7°C TP warming at the end of 21st century under the representative concentration pathway 8.5 (RCP8.5) scenario can enhance the AMOC by about 10%. Key Points: The Tibetan Plateau (TP) heating (cooling) can cause enhanced moisture transport from the North Atlantic (Pacific) to Pacific (North Atlantic)The TP heating (cooling) can strengthen (weaken) the Atlantic meridional overturning circulation (AMOC)The TP warming at the end of 21st century under the RCP8.5 scenario can lead to a 10% AMOC enhancement [ABSTRACT FROM AUTHOR]

The evolution of central Asian drylands during the Cenozoic is a hot topic in paleoclimate research, but the underlying mechanism remains unclear. Here, we investigate this topic with climate modeling based on six key geological periods. Our results indicate that central Asian drylands have existed since the early Eocene, after which they move northward and become narrower. Although changed land‐sea distribution and decreased atmospheric CO2 concentration promote the aridification of drylands, they only slightly affect the latitudinal position of drylands. By comparison, the growth of Asian high‐topography areas, especially the Tibetan Plateau (TP), makes central Asian drylands move northward, concentrate in narrow latitudinal bands, and increase in intensity. Good model‐data qualitative agreement is obtained for stepwise aridification in midlatitude inland Asia north of ∼40°N, and the uplifted main and northern TP by the early Miocene likely forced drylands to form in this region. Plain Language Summary: Drylands in central Asia (approximately 40–50°N, 70–105°E) have a very long and complex evolutionary history during the Cenozoic. Previous modeling studies have mainly considered specific geological period and factors; however, few attempts have been made to quantify the role of different factors on the characteristics of central Asian drylands through geologic time and to investigate the changes in these characteristics under different evolved scenarios of the Tibetan Plateau (TP). The mechanism behind the changes in position, range, and intensity of central Asian drylands during the Cenozoic remains unclear. In this study, we ran 44 experiments to investigate the respective roles of Asian topography, land‐sea distribution, atmospheric CO2 concentration and Antarctic ice sheet on central Asian drylands. Our model results indicate that central Asian drylands have existed since the early Eocene. The Paratethys Sea retreat and the atmospheric CO2 concentration reduction promote the aridification of drylands, but they only slightly affect the latitudinal position of drylands. With the growth of Asian high‐topography areas, especially the TP, central Asian drylands move northward, concentrate in narrow latitudinal bands, and increase in intensity. Key Points: Changed land‐sea distribution and atmospheric CO2 concentration promote aridification of drylands but only slightly affect their latitudinal positionThe growth of the TP makes central Asian drylands move northward, concentrate in narrow latitudinal bands, and increase in intensityThe uplift of the main and northern TP by the early Miocene likely forced the drylands to form in central Asia north of ∼40°N [ABSTRACT FROM AUTHOR]

The tectonic evolution of the Paleo‐Jinshajiang Ocean, and in particular the time of its closure, is debated. Here we present new constraints on the evolution of this region from an integrated paleomagnetic and geochronologic study of the Late Triassic Batang Group volcanic rocks in Qamdo, Eastern Qiangtang Terrane (EQT). Two zircon U‐Pb ages indicate that the volcanic rocks erupted at ∼227–222 Ma. New paleomagnetic results yield a robust Late Triassic paleopole of 57.6°N, 176.4°E (A95 = 7.8°), corresponding to a paleolatitude of 32.5 ± 7.8°N for the study area. Integrated with other lines of paleomagnetic and geological evidence, we show that the northward drift of the EQT placed it at the same paleolatitude as the Tarim Block by ∼227–222 Ma, which suggests that the Paleo‐Jinshajiang Ocean in the Qamdo region closed before that time, and likely around ∼230 Ma. Plain Language Summary: The closure of the Paleo‐Jinshajiang Ocean, which was one of the most important ancient oceans of Asia, closed when the Qiangtang Terrane (QT) collided with the terranes now located to the north of it. However, the evolution of this ocean, and especially the timing of its closure, are still debated. The drift history of the QT is a key to understanding the evolution of the Paleo‐Jinshajiang Ocean. We present here new constraints on the evolution of this region from an integrated paleomagnetic and zircon U‐Pb geochronologic study of Late Triassic volcanic rocks in Qamdo, Eastern QT. Two zircon U‐Pb geochronologic results indicate that the volcanic rocks erupted at ∼227–222 Ma. New paleomagnetic results yield a robust Late Triassic paleopole of 57.6°N and 176.4°E, and indicate that the study area was then located at a paleolatitude of 32.5 ± 7.8°N. In integrating these data with other lines of evidence, we show that a northward drift of the EQT since the early Permian brought it to the same paleolatitude as the Tarim Block by ∼227–222 Ma. This implies that the closure of the Paleo‐Jinshajiang Ocean in the Qamdo region occurred before 227–222 Ma, and likely around ∼230 Ma. Key Points: Volcanic rocks of the Late Triassic Batang Group are dated by U‐Pb on zircon to ∼227–222 MaPaleomagnetic data from these rocks yield a robust Late Triassic paleopole of 57.6°N, 176.4°E(A95 = 7.8°)Closure of the Paleo‐Jinshajiang Ocean occurred before 227–222 Ma, and likely around ∼230 Ma [ABSTRACT FROM AUTHOR]

Targeted adaptation to near‐term climate change requires accurate, reliable, and actionable climate information for the next few decades. Climate projections simulate the response to radiative forcing, but are subject to substantial uncertainties due to internal variability. Decadal climate predictions aim to reduce this uncertainty by initializing the simulations using observations, but are typically limited to the next 10 years. Here, we use decadal predictions to constrain climate projections beyond the next decade and demonstrate that accounting for climate variability improves regional projections of 20‐year average temperatures. Applying this constraint to climate projections of the near future until 2035, summer temperatures over land regions in Asia and Africa tend to show stronger changes within the warming range simulated by the larger, unconstrained, ensemble—consistent with a warm phase in North Atlantic variability. This improved regional climate information can enable tailored adaptation to climate changes in the coming decades. Plain Language Summary: We present a novel approach to reduce the uncertainty from internal variability, which can limit the capability to develop suitable adaptation strategies, in climate projections of the near future. This approach combines information from decadal climate predictions and climate projections to constrain decadal climate variability. We demonstrate that this constraint improves the skill of temperature projections for the next 20 years after starting the prediction. Applying this method to predict the near‐term future until 2035, we find an increased probability of stronger warming during summer in several land regions, consistent with a warm phase in North Atlantic variability. Such improved estimates of near‐term climate change are a promising basis for developing better adaptation strategies and avoiding mal‐adaptation. Key Points: We present a novel approach to reduce the uncertainty and improve the accuracy of near‐term climate projectionsThe method merges decadal predictions with climate projections, constraining the decadal variability in the projectionsThis approach increases the skill of regional temperature projections for the next 20 years [ABSTRACT FROM AUTHOR]

The Intertropical Convergence Zone (ITCZ) is a band of vigorous convection and high precipitation formed by the confluence of southeasterly and northeasterly trade winds, and acts as a barrier to cross‐equatorial dust transport. We investigate the provenance of dust in the surface sediments of 16 cores collected along a 131.5°W transect from the equator to 16°N in the central Pacific. The results reveal well‐defined Asian dust signals north of 7°N and mixed Asian–South American source signals south of 6°N. We propose the southernmost latitude with an intact Asian source signal (7°N) as the present‐day mean ITCZ position in terms of dust provenance in the central Pacific. This geochemically defined mean ITCZ position reflects differences in thermal and dust fluxes between hemispheres and can be used as a reference for quantitatively assessing ITCZ displacement in the sedimentary down‐core records back to ca. 14 Ma. Plain Language Summary: The Intertropical Convergence Zone (ITCZ), a band of heavy precipitation in the tropics, migrates latitudinally towards the warmer hemisphere on seasonal and longer timescales. The past and future latitudinal position of the ITCZ is of great interest to the scientific community as the ITCZ influences global temperature and precipitation patterns as well as the hydroclimate of the tropics. The position of the ITCZ can be identified by tracking changes in dust sources and fluxes between hemispheres, as the ITCZ acts as a barrier to cross‐equatorial dust transport. Here, we use geochemical analysis to investigate the regional sources of dust on the seafloor in various sites in the tropical central Pacific to define the mean present‐day position of the ITCZ. We find that dust deposited north of 7°N is predominantly from Asia and dust deposited south of 6°N is mostly from Asia and South America. We propose the southernmost latitude with an intact Asian source signal (7°N) as the present mean ITCZ position in the central Pacific. This geochemically defined mean ITCZ position can be used as a reference for the quantitative assessment of ITCZ displacement in the past using sedimentary down‐core records. Key Points: Dust originating from the Northern Hemisphere reaches at least 2°N in the central Pacific, traveled across the boreal winter Intertropical Convergence Zone (ITCZ) at 4°N7°N, the southernmost latitude with an intact Asian source signal, is suggested as the geochemically defined present‐day mean ITCZ positionThe newly defined mean ITCZ position can be used as a reference for the quantitative assessment of ITCZ displacement in down‐core records [ABSTRACT FROM AUTHOR]

Combined NO2 and CO2 observations have the potential to constrain the identification of the locations and strength of urban CO2 emissions, in particular, point sources such as power plants. We report the first results of airborne spectroscopic NO2 and CO2 observations over an urban area in Japan in February 2018. Inversed emission rates of two stacks of the coal‐fired power plant for CO2 showed relatively good agreement with those estimated by a bottom‐up inventory—the Regional Emission inventory in ASia (REAS) v3.1—within −7% to 40% because the plume shapes were well identified due to constraint by NO2 measurements. The estimated NOx emission rates showed discrepancies more than 80% with those estimated by the REAS v3.1, mainly due to the uncertainties in activity data and emission factors, or in the greatly varying NO/NO2 ratios in fresh plumes, which warrant further investigations when estimating NOx emissions from satellite NO2 observations on km‐scales. Plain Language Summary: Burning of fossil fuels at high temperatures constitutes a major anthropogenic source of nitrogen oxides (NOx) and carbon dioxide (CO2). While CO2 stays in the atmosphere for hundreds of years, thereby being a well‐mixed gas, NO2 has a much shorter lifetime of only a few hours. This substantial difference in lifetime between NO2 and CO2 means that concurrent NO2 and CO2 observations obtained by the same platform can be used to identify the locations and strength of CO2 emissions from point sources such as power plants. In February 2018, for the first time, we obtained concurrent airborne spectroscopic NO2 and CO2 observations over an urban area, to demonstrate the traceability of NO2 to CO2. The plumes of co‐emitted NO2 and CO2 were derived from measured spectra. The plumes of NO2 and CO2 co‐emitted from the stacks of power plants were well identified owing to constraint by NO2. Uncertainties of inversed emission rates were statistically derived. For CO2, the results were within 40% in agreement with a bottom‐up emission inventory known as REAS v3.1. For NOx, however, a disagreement of 80% was identified, likely due to the uncertainties of the inventory data or in the NOx partitioning in fresh plumes. Key Points: Concurrent observations of NO2 and CO2 in fresh plumes from a large single point source using airborne spectrometers were reportedColumnar enhancements of NO2 and CO2 due to power plant emissions were up to 3.8 × 1016 molec.cm−2 and 75 ppm, respectivelyPlume shapes of CO2 emitted from power plants were well identified and constrained by NO2 plume shapes [ABSTRACT FROM AUTHOR]

Recent time-series from sediment traps show abnormally high chlorophyll-a concentrations and primary productivity in the oligotrophic central South China Sea (SCS), especially during wintertime. Here we present new insights from compound-specific hydrogen isotopic analysis of leaf wax n-alkanes and Sr-Nd isotope compositions extracted from four basin-wide surface sediment transects. We find that the deepest surface sediments in the central basin contain the most depleted n-alkane hydrogen isotopes, suggesting inputs from higher latitude soils in northern China. This is supported by the Sr-Nd isotope compositions of the same surface sediments. We propose that aeolian dust is transported by the winter monsoon and might fertilize the phytoplankton bloom in the central SCS. This process may have been enhanced in ancient times when the winter monsoon was stronger, driving both vertical mixing and dust transport to the central basin. Plain Language Summary Recent studies observe abnormally high winter primary productivity and nitrate concentrations in the surface waters of the central South China Sea (SCS). However, this is a nutrient limited region of the ocean, so the drivers of this primary productivity are unclear. Here we analyze leaf wax carbon and hydrogen isotopes, and Sr-Nd isotopes, along four shallow-to-deep-water sediment transects to trace the sources of dust and organic matter in the sediments of the central basin. Our results suggest the central basin sediments receive significant terrestrial inputs of dust and nutrients from northern Asia via long-range aeolian transport during the winter monsoon. These results give new insights to terrestrial-marine connections and the carbon cycle of the SCS. This process may provide a new mechanism to understand the glacial-interglacial productivity changes in marginal seas. [ABSTRACT FROM AUTHOR]

Paleocene lavas of the Dianzhong Formation preserved in the Linzhou Basin of South Tibet provide a unique opportunity to constrain the initial geometry of the India‐Asia collision; however, earlier studies argued a complex magnetic signature resulting from thermal and/or chemical remagnetizations. To better characterize the remanences obtained from the Dianzhong lavas, we carried out an intraformational conglomerate test on a previously‐studied section in the Linzhou Basin. The positive conglomerate test suggests that the characteristic remanences reported from the Dianzhong Formation are primary. The updated Paleocene pole confirms a paleolatitude of 6.7° ± 4.4°N for the Lhasa terrane and positions the southern margin of Asia in the equatorial humid belt. An initial collision, between India, Asia and an intra‐oceanic arc in the equatorial humid belt, may have intensified silicate weathering and resulted in an extra consummation of carbon dioxide, which contributes to a long‐term cooling of the Earth during the Cenozoic. Plain Language Summary: The locus of the initial India‐Asia collision can be constrained using paleomagnetic studies on the Paleocene volcanics from the Linzhou Basin, South Tibet. However, the primary nature of the magnetic signature previously reported from the Dianzhong Formation was questioned. This study carries out an intraformational conglomerate test collected from the middle part of the Dianzhong Formation. The stable remanences isolated from a layer of intercalated lava cobbles yield a random distribution in contrast to the well‐grouped directions obtained from the over‐ and underlying lava layers resulting in a positive conglomerate test. We therefore argue for a primary nature for the characteristic remanence recorded by the Dianzhong lavas from the Linzhou Basin. Our study confirms a low latitude of ∼7°N, that is, within the equatorial humid belt, for the southern margin of Asia during ∼64–60 Ma. An initial low‐latitude collision between India and Asia is critical for understanding the tectonic and climatic significance of the India‐Asia collision. Key Points: Characteristic remanences reported from the Dianzhong lavas in the Linzhou Basin are primary in originThe updated Paleocene pole confirms a low latitude of ∼7°N for the Lhasa terraneAn initial collision between India, Asia and an oceanic arc in the equatorial humid belt may contribute to the Cenozoic cooling of the Earth [ABSTRACT FROM AUTHOR]

Many nations responded to the corona virus disease‐2019 (COVID‐19) pandemic by restricting travel and other activities during 2020, resulting in temporarily reduced emissions of CO2, other greenhouse gases and ozone and aerosol precursors. We present the initial results from a coordinated Intercomparison, CovidMIP, of Earth system model simulations which assess the impact on climate of these emissions reductions. 12 models performed multiple initial‐condition ensembles to produce over 300 simulations spanning both initial condition and model structural uncertainty. We find model consensus on reduced aerosol amounts (particularly over southern and eastern Asia) and associated increases in surface shortwave radiation levels. However, any impact on near‐surface temperature or rainfall during 2020–2024 is extremely small and is not detectable in this initial analysis. Regional analyses on a finer scale, and closer attention to extremes (especially linked to changes in atmospheric composition and air quality) are required to test the impact of COVID‐19‐related emission reductions on near‐term climate. Plain Language Summary: Many nations responded to the COVID‐19 pandemic by restricting travel and other activities during 2020. This caused a temporary reduction in emissions of CO2 and other pollutants. We compare results from twelve Earth system models to see if the emissions reductions affected climate. These twelve models performed over 300 experiments using multiple initial‐conditions. We find a consensus that aerosol amounts were reduced, especially over southern and eastern Asia, during 2020‐2024. This led to increases in solar radiation reaching the surface in this region. However, we could not detect any associated impact on temperature or rainfall. We recommend more analyses on regional scales. We also suggest that analysis of extreme weather and air quality would be useful to test the impact on climate of emission reductions due to COVID‐19. Key Points: Lockdown restrictions during COVID‐19 have reduced emissions of aerosols and greenhouse gases12 CMIP6 Earth system models have performed coordinated experiments to assess the impact of this on climateAerosol amounts are reduced over southern and eastern Asia but there is no detectable change in annually averaged temperature or precipitation [ABSTRACT FROM AUTHOR]

The timing of the India‐Asia collision onset, essential to understanding the evolution of the Himalayan‐Tibetan orogen, has been widely investigated through multidisciplinary approaches. Among these, the India to Asia provenance reversal (IAPR) documented in the Indian passive margin successions has proved to be most effective. We present integrated stratigraphic, sedimentological, and provenance data on Upper Cretaceous‐Paleogene strata from the newly investigated Mubala section exposed south of the Yarlung‐Zangbo suture zone (YZSZ) in southern Tibet, which preserves continuous deep‐marine turbiditic and biogenic sedimentation on the distal Indian passive margin. Sandstone petrography, heavy minerals, detrital zircon geochronology and Hf isotopes, and detrital Cr‐spinel geochemistry constrain the IAPR to later than 62.7 Ma (youngest zircon ages from the earliest Asian‐derived sandstone) and by 61.0 ± 0.3 Ma (SIMS age of a tuffaceous layer ∼30 m above this bed). The onset of intercontinental collision along the YZSZ began by 61 Ma. Plain Language Summary: The India‐Asia collision, ultimately leading to uplift of the Himalayan Mountains and Tibetan Plateau, has greatly influenced global climate and oceanic circulation. The timing of collision is essential to reconstruct the growth history of the Himalayan‐Tibetan orogen and its environmental and paleogeographic effects. The change in sediment provenance documented along the Indian continental margin has proved to be a most effective method to constrain the timing of initial collision. We here report a newly‐discovered sedimentary succession deposited onto the deep‐marine edge of India, in which strata composed of detritus derived entirely from India are overlain by strata composed of detritus derived instead from Asia. This provenance change took place later than 62.7 million years ago (Ma; which is the age of the youngest group of zircons contained in the oldest sandstone derived from Asia) and 61.0 ± 0.3 Ma (which is the age of zircon crystals contained in a volcanic tuff found 30 m above the oldest Asian‐derived sandstone). The Indian and Asian continents thus first came into direct contact by 61 Ma. Key Points: Sandstones derived first from India and next from Asia constrain India‐Asia collision onsetThe India‐Asia provenance reversal is bracketed between 62.7 and 61 Ma in the Mubala sectionSubduction of the Indian continental margin beneath Asia began by 61 Ma [ABSTRACT FROM AUTHOR]

The projected monsoon hydrological sensitivity, namely, the precipitation change rate per kelvin of global warming, shows substantial intermodel spread among 40 Coupled Model Intercomparison Project phase 5 models. The hydrological sensitivity of the Northern Hemisphere summer monsoon is negatively correlated with that of the Southern Hemisphere summer monsoon. The intermodel spread of the Northern Hemisphere summer monsoon hydrological sensitivity is mainly attributed to the projected interhemispheric temperature gradients and the associated low‐level cross‐equatorial flows. The intermodel spread of the Afro‐Asia summer monsoon sensitivity is rooted in the projected continent‐ocean thermal gradients, while the spread of the North American monsoon sensitivity is related to the projected sea surface temperature pattern in the tropical eastern Pacific and Atlantic. These findings suggest that further constraining monsoon hydrological sensitivity requires a better projection of the warming rate between the Northern and Southern Hemispheres and between the land and ocean, and the sea surface warming pattern in the tropical eastern Pacific and Atlantic. Plain Language Summary: Global monsoon precipitation has far‐reaching impacts on agriculture planning and social‐economic sustainable development. Previous studies suggested that the increasing of global monsoon precipitation is sensitive to global warming rate, but the precipitation sensitivities, i.e., the precipitation change rate per kelvin of global warming, are also different among state‐of‐the‐art coupled models. The causes of uncertainty in the monsoon precipitation sensitivity and the associated dominant physical mechanism remain elusive. Based on 40 state‐of‐the‐art coupled climate models, we reveal that the greenhouse gas‐induced interhemispheric temperature gradient causes the uncertainty of global monsoon precipitation sensitivity by changing the strengths of monsoon circulation and Hadley circulation and altering the Intertropical Convergence Zone position. Our results highlight the importance of a reliable projection of interhemispheric differential warming to the future change of global monsoon precipitation. Key Points: Substantial intermodel spread of GM hydrological sensitivity in the CMIP5 models is foundThe intermodel spread of projected GM hydrological sensitivity could be attributed to the projected interhemispheric temperature gradientThe intermodel spread of regional monsoon hydrological sensitivity is attributed to the projected land‐ocean temperature gradient and SST pattern [ABSTRACT FROM AUTHOR]

When and how the TP underwent uplift and deformation are still under heated debate. We present paleomagnetic evidence for the NB in the northeastern central TP to help decipher the potential plateau deformation mechanism. Magnetostratigraphy with zircon U‐Pb age of volcanic rock demonstrates that the NB basin deposited during 52.5–35.0 Ma. Paleomagnetic declinations indicate that the basin experienced counterclockwise rotation of 25.9 ± 7.2° during 52–46 Ma and clockwise rotation of 24.4 ± 9.7° during 41–35 Ma, which coexisted with the intrusion and explosion of volcanic rocks at 51–46 and 39–35 Ma. We proposed a stepwise compression and extrusion model to interpret the basin deposition, rotation, and volcanism by northward compression and eastward extrusion of the eastern Lhasa and Qiangtang Blocks (Proto‐TP) in relation to the Sichuan Basin as early response to the India‐Asia collision. Plain Language Summary: How the Tibetan Plateau (TP) adjusted its inner crustal thickening and tectonic deformation during the India‐Asia collision is still in hot debate, for example, through lateral extrusion or continuous distribution. The Nangqian Basin (NB) is located in the bending (transitional) part from an east‐west tectonic area in the central TP to a north‐south tectonic area in the eastern and southeastern TP. It is an ideal location to provide abundant tectonic evidences for the plateau deformation and uplift models. We report a detailed paleomagnetic dating of the Paleogene sedimentary sequence from the NB with a complete paleomagnetic rotation analysis. Radiometric and magnetostratigraphic dating suggested that the NB commenced its deposition at 52.5 Ma and ended at 35.0 Ma. Paleomagnetic declination data reveal a change of rotation sense of the NB, from a counterclockwise rotation of 25.9° at 52–46 Ma to a clockwise rotation of 24.4° at 41–35 Ma. Integrated with other lines of geological evidence, we believe that the Eocene deformation, rotation, and uplift of the south and east central TP in response to the early India‐Asia collision can be explained by stepwise compressions and eastward extrusions. Key Points: Magnetostratigraphic results demonstrate that the Early Cenozoic sedimentary sequence of the Nangqian Basin yields ages of 52.5–35.0 MaDeclination data indicate change of rotation in the Nangqian Basin from counterclockwise during 52–46 Ma to clockwise during 41–35 MaThe Eocene deformation, rotation, and uplift of the east central Tibetan Plateau favor the compression and extrusion model [ABSTRACT FROM AUTHOR]

The processes controlling middle‐latitude environmental changes are poorly understood. Both high‐latitude ice sheets and tropical oceans can affect climate and environments in middle latitudes, but separating their relative contribution is challenging. Coincidence of intensive Northern Hemisphere glaciations and increased dust accumulation rates at ~2.7 Ma on the Chinese Loess Plateau and North Pacific Ocean is often used to indicate high latitudes' dominant role on middle‐latitude climate change. Here we present new and compile available evidence from the Qaidam Basin and the Tarim Basin of central Asia demonstrating a phase of drying at ~3.3 Ma. The drying is synchronous with proposed timing of closure of the Indonesian Seaway, which has been suggested to cause significant oceanic surface heat adjustments and corresponding decreased heat and moisture transport to middle/high latitudes. These new results suggest a tropical forcing of aridification for the late Pliocene central Asian environmental evolution. Plain Language Summary: The timing and forcing mechanisms for past climate changes are instructive to predict future variations. It is widely believed that the aridification of central Asia and changes in monsoonal climate on the Chinese Loess Plateau formed at the Pliocene‐Quaternary boundary forced by intensive Northern Hemisphere glaciations at ~2.7 Ma. In this study we demonstrate that aridification began earlier within the Qaidam and Tarim Basins, at ~3.3 Ma, when no significant change occurred for Northern Hemisphere ice sheets. Instead, this event was aligned with tropical Indian Ocean cooling as a result of closure of the Indonesian Seaway. Thus, we attribute this earlier drying event to tropical forcing rather than cryospheric change. This study reinterprets the forcing of aridification in central Asia and suggests that understanding future environments in this ecologically fragile region needs to consider tropical forcing. Key Points: We detected an earlier drying of central Asia at ~3.3 Ma, inconsistent with Loess Plateau and Pacific Ocean dust accumulation recordsThis phase of central Asian drying is synchronous with Indian Ocean cooling caused by Indonesian Seaway closureOur results suggest tropical forcing for central Asian drying at ~3.3 Ma [ABSTRACT FROM AUTHOR]

The evolution of Cenozoic climate patterns in Asia has been linked to uplift of the Tibetan Plateau (TP), retreat of the Paratethys Sea, and global cooling. However, less attention has been placed on the latitudinal change of the TP. Here we report new climate modeling to explore how modern climate changes as a function of topographic growth and spatial migration of the TP. Our results show that the northward displacement of the uplifted proto‐TP within the subtropics can significantly affect the wind and precipitation pattern over East‐Central Asia. By compiling proxy‐based climatic records, paleolatitudinal and paleoelevational evolution models of the proto‐TP, and in comparison with previous modeling under a global paleogeography, we suggest that the northward migration of the proto‐TP in the Paleogene could have intensified the aridity in Central Asia, but its influence on East Asian precipitation and monsoonal circulation could be dependent on the paleogeography and other boundary conditions. Plain Language Summary: The evolution of the Asian monsoons and aridification of Asia's interior are thought to be driven by Tibetan‐Himalayan uplift. Recent geological observations suggest that the uplifted proto‐Tibetan Plateau (proto‐TP) migrated northward in the subtropics since the early Eocene and reached its present position by the latest Oligocene. We therefore simulated the effects of this process on East‐Central Asian climate. Our climate modeling shows the northward migration of the high proto‐TP from 21–29°N to 29–37°N can significantly change the present‐day wind and precipitation patterns over East‐Central Asia. Especially, Central Asia become drier because of the displacement of the anomalous dry belt caused by large‐scale atmospheric subsidence. We further suggest that forcing by the paleolatitudinal migration of the high proto‐TP within the subtropics from the Eocene to the earliest Miocene could have drove the Central Asian paleoclimate to dryer conditions, but migration might not be the sole parameter that governed the East Asian monsoon during the Paleogene. Key Points: The high proto‐Tibetan Plateau migrating northward can notably influence the modern East‐Central Asian climate systemCentral Asian aridification increased with the northward migration of the proto‐Tibetan Plateau in the PaleogeneThe impact of Paleogene proto‐Tibetan Plateau migration on East Asian climate could be dependent on boundary conditions [ABSTRACT FROM AUTHOR]