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There are many types of atmospheric heat engines in land-air systems. The accurate definition, calculation and interpretation of the efficiency of atmospheric heat engines are key to understanding energy transfer and transformation of land-air systems. The atmosphere over the Qinghai-Tibet Plateau (QTP) in summer can be regarded as a positive heat engine. The study of the heat engine efficiency is helpful to better understand land-air interaction and thermal-dynamic processes on the QTP. It also provides a new perspective to explain the impact of the QTP on the climate of China, East Asia and even the world. In this paper, we used MOD08 and ERA5 reanalysis data to calculate the atmospheric heat engine efficiency, surface heat source and atmospheric heat source on the QTP in summer (May to September) from 2000 to 2020. The average atmospheric heat engine efficiency on the QTP in summer from 2000 to 2020 varies between 1.2% and 1.5%, which is less than 1.6%; the heat engine efficiency in summer is higher than that in June, July and August; the Qaidam Basin is the region with the highest atmospheric heat engine efficiency, followed by the western QTP. The mean surface heat source on the QTP in summer from 2000 to 2020 is 96.0 W m−2, the atmospheric heat source is 90.7 W m−2, and the release of precipitation condensation latent heat is the most important component of the atmospheric heat source on the QTP in summer. There is a strong and significant positive correlation between the atmospheric heat engine efficiency and the surface heat source on the QTP in summer. The precipitation con densation latent heat is the most important component of the atmospheric heat source in summer and can reflect the precipitation process. There is a strong and significant negative correlation between the atmospheric heat engine efficiency and the atmo spheric heat source on the QTP in summer. [ABSTRACT FROM AUTHOR]

Climate and climate change have always been a research focus of atmospheric sciences. This paper summaries research efforts, achievements and international contributions of the Chinese scientific community on climate and climate change over the past 70 years. The review is based on papers published officially in national or international scientific journals, and is organized to cover six aspects: (1) general climate studies; (2) impact of the Qinghai-Tibetan Plateau; (3) impact of the East Asian monsoon; (4) influences of teleconnection oscillation and westerlies; (5) climate dynamics and development of climate models; and (6) climate change. It is, however, to be noted that the present review can not be considered as an exhaustive one, since there is a huge body of literature in the field. [ABSTRACT FROM AUTHOR]

Grass carp (Ctenopharyngodon idella) is a cyprinid species, widely living in the freshwater on the plain area of East Asia. The fish has characteristic comb-like pharyngeal teeth, an adaptation to their typical vegetarian feeding habit. This paper deals with fossil pharyngeal teeth that related to grass carp, found from about 20 localities, ranging from the lower Oligocene to Holocene. Based on the morphology of the teeth, we established two new genera and species related to the genus Ctenopharyngodon (Dezaoia saintjaquensis, Eoctenopharyngodon liui) and two new species of Ctenopharyngodon (C. xiejiaensis and C. orientalis). The first recognized C. idella pharyngeal teeth were from the lower Pliocene of Yushe, Shanxi, and many others from 11 Pleistocene to Holocene localities. Judged from the materials and their occurrences, the grass carp may have originated from the western part of China during the early Oligocene. Throughout the Miocene, the grass-carp-like pharyngeal teeth were discovered from a vast area in China, indicating an appropriate atmosphere for the grass carp to develop, although the climate in the western part of China was possibly drier than that in the eastern part. From the beginning of the Pliocene, as the consequence of a considerable uplift of the Tibetan Plateau, the large rivers in East Asia finally formed, created favorable conditions for the Recent grass carp to thrive. Most teeth were collected in association with fossil mammals. Therefore, we are using the associated fossil mammals as the checking reference against which to test our interpretation of the surrounding environment of the water system in which the grass carp lived. [ABSTRACT FROM AUTHOR]

In the late 1920's, a mega-drought in China resulted in widespread crop failure and famine. Sufficient evidence suggests that this drought belonged to a dry period ranging from approximately 1922 to 1932. To understand the characteristics and the cause of this persistent drought period, we combined various data, including observations, tree ring proxy data, reanalysis data, simulation results of the Fifth Phase of the Coupled Model Intercomparison Project and numerical downscaling simulations. The results show that during 1922–1932, most regions in eastern China suffered from a persistent drought that lasted for six years, and the maximum negative precipitation anomaly reached −1.5 times the standard deviation. Given its spatial coverage, duration, and strength, the 1920s drought was unique for the 20th century. The 1920s drought was primarily caused by internal variability. Strong easterlies in lower latitudes, strong monsoon circulation, and abnormally high geopotential heights at middle and upper levels were responsible for the 1920s drought conditions in eastern China; these drought conditions could be further attributed to the joint impact of the Atlantic Multidecadal Oscillation, Pacific Decadal Oscillation and Indian Ocean Basin Mode. [ABSTRACT FROM AUTHOR]

Although alpine ecosystems have been commonly recognized as sensitive to recent climate change, few studies have examined its impact on the long-term productivity of vegetation and soil erosion. Using paleoecological records, these two aspects were examined in the alpine zone of the Taibai Mountains (elevation, 3767 m) in monsoon-dominated East Asia since the middle Holocene. Proxies for the productivity of vegetation and severity of soil erosion from high-resolution alpine lacustrine records show that the productivity was closely related to mean annual temperature and soil erosion, to summer precipitation from the East Asian Summer Monsoon (EASM). Specifically, when the mean annual temperature was low and precipitation was abundant, during 5800–4000 calendar years before the present (cal. yr BP), the alpine ecosystem was characterized by low vegetation productivity and severe soil erosion. However, the productivity increased and soil erosion decreased from 4000 cal. yr BP onwards. These results highlight the role of paleoecological evidence in studying ecosystem services on longer time scales, which is significant in making policies for sustainable development under climate change in regions for which such long-term monitoring data are not available. [ABSTRACT FROM AUTHOR]

The Late Triassic Tianqiaoling flora is well-known in China, and its discovery has changed our understanding of Chinese Late Triassic phytogeographical divisions. More broadly, this flora has great significance for the study of phytogeography in East Asia during this time. However, the previous dating of this flora was only evidenced by plant fossils and stratigraphic correlation, and the accurate dating has still not been achieved. In this study, rhyolite samples were collected from the bottom of the Tianqiaoling Formation, which is conformally contacted the Tianqiaoling flora-bearing beds. The results of new U-Pb dating gave ages for the rhyolites of 212.8±2.5 Ma, indicating the end of Malugou Formation and initial Tianqiaoling Formation in deposition occurred in the late Norian (~227–208.5 Ma), which is contemporaneous with the peak of the Tianqiaoling flora in development. Our radiometric dating results are basically consistent with paleobiological evidence. The new age provides a key anchor point for regional stratigraphic correlation of the Tianqiaoling flora with its related Late Triassic floras, and contribute to a better understanding of the geology and phytogeography in the East Asia, particularly in the "triangle region" covering the eastern Jilin (China), South Primorye (Russia) and Southwest Japan, during the Late Triassic. [ABSTRACT FROM AUTHOR]

Stalagmite is one kind of secondary carbonates formed in limestone caves (speleothem). After cave water droplets containing Ca2+ and H C O 3 − drip onto floor, carbonate in the water might become supersaturated due to CO2 degassing under certain conditions, resulting in the formation of stalagmite in a process year after year. Stalagmite is one of important geological archives for paleoclimate research. The advantages include wide spatial distribution, suitable for U-Th and U-Pb dating, enriched in climate proxies, continuity, long time span, comparability and lower sampling cost etc. These factors have propelled stalagmite paleoclimate research to the forefront of global paleoclimatology with an irreplaceable role. The stalagmite paleoclimate study started in the western countries, mainly in Europe and America in 1960s–1970s, while the relevant research in China was progressively developed in the 1980s–1990s after the Reform and Opening up. Although there was a huge gap between the overall research level in China and western countries, a solid research foundation, as well as a number of talent teams were established during the period. In the 21st century, starting from the publication of stalagmite records from Hulu Cave in Nanjing in 2001, the stalagmite paleoclimate research in China has ushered in a flourishing development and a real leap on the basis of international cooperation, resulting in significant international impacts. The landmark achievements, including establishment of the world's longest (640000 years) East Asian monsoon stalagmite record, as well as the longest Indian monsoon (280000 years), South American monsoon (250000 years), North American westerly climate (330000 years), Central Asian westerly climate (135000 years), and northwestern China westerly climate (500000 years), have laid a milestone in the paleoclimate study in these climate domains. Importantly, these stalagmite records have revealed the relationship of Asian monsoon variations with solar insolation climate change in polar regions, and the South American monsoon changes on orbital-suborbital timescales, which have provided new geological observations for the development of orbital-suborbital climate theory; elaborated coupling and differentiation relationships between the Asian monsoon and the westerly climate; reconstructed the history of Asian monsoon changes in the Holocene in detail, and thus the hydrological and climate variances behind Chinese and Indian civilization-cultural evolutions. Furthermore, a large number of high-resolution stalagmite records over the past 2000 years have been reconstructed, which are important for understanding short-term climate variability and magnitude, events, cycles, and thus the future climate projection. The achievements have also involved the improvements of a number of important techniques, such as U-Th dating method, the establishments of various hydroclimatic proxies, as well as the contributions to the reconstruction of the atmosphere 14C variation history over the past ∼54000 years. On the perspective of the future, the Chinese stalagmite community should continue to develop key techniques, further clarify the hydroclimatic significance of stalagmite proxies, impel the integration of related disciplines, and concentrate on key scientific issues in global climate change and major social demands. [ABSTRACT FROM AUTHOR]

The impact of global warming on the climate of northern China has been investigated intensively, and the behavior of the East Asian monsoon during previous intervals of climatic warming may provide insight into future changes. In this study, we use paleovegetation records from loess and lake sediments in the marginal zone of the East Asian summer monsoon (EASM) to reconstruct the EASM during the interval of warming from the Last Glacial Maximum (LGM) to the Holocene. The results show that during the LGM, desert steppe or dry steppe dominated much of northern China; in addition, the southeastern margin of the deserts east of the Helan Mountains had a distribution similar to that of the present-day, or was located slightly further south, due to the cold and dry climate caused by a strengthened East Asian winter monsoon (EAWM) and weakened EASM. During the last deglaciation, with the strengthening of the EASM and concomitant weakening of the EAWM, northern China gradually became humid. However, this trend was interrupted by abrupt cooling during the Heinrich 1 (H1) and Younger Dryas (YD) events. The EASM intensified substantially during the Holocene, and the monsoon rain belt migrated at least 300 km northwestwards, which led to the substantial shrinking of the desert area in the central and eastern part of northern China, and to the large expansion of plants favored by warm and humid conditions. Paleoclimatic records from the marginal zone of the EASM all show that the EASM reached its peak in the mid-Holocene, and past global climatic warming significantly strengthened the EASM, thereby greatly improving the ecological environment in northern China. Thus, northern China is expected to become wetter as global warming continues. Finally, high resolution Holocene vegetation records are sparse compared with the numerous records on the orbital timescale, and there is a need for more studies of Holocene climatic variability on the centennial-to-decadal scale. [ABSTRACT FROM AUTHOR]

Three cores (ZY-1, ZY-2 and ZY-3) retrieved from the Central Yellow Sea mud (CYSM) were analyzed in sensitive grain size and AMS C dating to reconstruct the history of the East Asian Winter Monsoon (EAWM) since the Middle Holocene in the study area. The results show that these data provide a continuous history of the EAWM over the past 7.2 ka and that the EAWM can be divided into three periods: strong and highly fluctuating during 7.2-4.2 ka BP; moderate and relatively stable during 4.2-1.8 ka BP; and weakened during 1.8-0 ka BP. Compared with the East Asian Summer Monsoon (EASM) recorded in the previous studies, the evolutionary history of the EAWM broadly follows the orbital-derived winter insolation with a similar long-term step-decreased trend as the EASM. At the centennial scale, however, the EAWM intensified events correlate well with the EASM weakened events and the North Atlantic climatic variations (Bond events 0 to 5) within the dating error, most likely forced by the reduction of solar irradiance through changes in the oceanic-atmospheric circulation patterns. [ABSTRACT FROM AUTHOR]