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Arid and semiarid regions are environmentally vulnerable to global warming. Thus, studying their environmental history during warm periods (e.g., the Last Interglacial, LIG) is crucial for understanding their future changes too. The West Gobi Desert is a transitional zone influenced by the westerlies and the East Asian monsoon system. Therefore, the variation in atmospheric circulation profoundly affects its water vapor transport and landscape evolution. Due to the scarcity of continuous records, the moisture transport process remains ambiguous, which limits further research on paleolake evolution and aeolian activity. Here, we combine paleoclimate simulations from the Coupled Model Intercomparison Project 6 (CMIP6)-Paleoclimate Modeling Intercomparison Project 4 (PMIP4) and geological records to clarify the water vapor transport pathways and aeolian activity in the West Gobi Desert during the LIG, compared to the reference period (the piControl). Our results show that increased rainfall and meltwater were possible supplies for surface water during the LIG and were associated with enhanced East Asian summer monsoon and higher surface air temperatures. Concomitantly, weakening aeolian activity and dormant dune fields occurred in the West Gobi Desert, resulting from higher surface moisture content and weaker surface wind regimes associated with the weakening westerlies and East Asian winter monsoon. Notably, the limited weakening of aeolian activity that occurred in the LIG winter and spring was caused by weaker surface wind and deteriorating surface moisture conditions, while the significant dormancy of dune fields in the LIG summer and autumn was initiated by the combined effects of ameliorative surface moisture conditions and lower surface wind speed. • West Gobi Desert water supply rose due to stronger East Asian summer monsoon and warm climate during the Last Interglacial (LIG). • Weaker winds and higher moisture led to dormant aeolian activity in West Gobi Desert during the LIG. • LIG warm season saw more significant weakening of aeolian activity than the cold season in West Gobi Desert. [ABSTRACT FROM AUTHOR]

The development and transformation of barchan-parabolic dune can be led by vegetationestablishment, which may be induced by climate change (precipitation, temperature, andwind strength) and/or human intervention. The impact of wind strength change-inducedvegetation restoration on dunes morphology and theirs surface sedimentary features isneglected in the Maowusu Sandy Land. In this study, we combined datasets of NormalizedDifference Vegetation Index (NDVI) and climatic factors to analyze temporal changes invegetation growth and their response to changes in temperature, precipitation and windstrength in the northern margin of Maowusu Sandy Land from 1982 to 2015. Growing seasonNDVI is related to the significant decrease in drift potential (DP) during the entire studyperiod. Further temporal analyses indicate that the growing season NDVI trends are largelycontributed by wind strength and temperature changes during the earlier study period1982-2006. And then, the increasing NDVI is consistent with the slightly increasing trend ofprecipitation during the recent study period 2006-2015. Thus, the transformation ofthe transitional dune cannot be explained by the increasing trend of wind strengthchange-induced vegetation alone. During the recent period, once dunes are covered byvegetation, the change in wind strength cannot mobilize the stable dunes becausethe vegetation provides an effective buffer preventing sand erosion. To reveal theresponse of sedimentological reorganization during the dune transformation processes,grain-size characteristics along the longitudinal profile of three different types of duneswere examined. From barchan dune through transition dune to parabolic dune, withthe increase of the fine sands (125-250μm) proportions, the mean grain size MZgradually decreases; in addition, as the very fine sands (<125μm) class increases, thesorting σ1 of sand dunes gradually became worse. The decreasing wind strengthlead to partly transport of fine sands on the upper part of dune windward slope,resulting in the progress coarsening and the reduction of dune height at the crestarea. No distinct trend in sorting and mean grain size on the windward slope oftransition dune, indicating that sand in transport had little influence on the particle sizedistributions. Conversely, the progressive of sorting and coarsening of sands towards thecrest of parabolic dune, implying that vegetation limited the sands from upwind ofdune, changed the effective source of dune into the underlying source deposits orreworking pre-existing aeolian deposits and trapped the sands on the crest area. [ABSTRACT FROM AUTHOR]

The Kubuqi Desert is the only active sand sea in the semiarid regions of northern China and occurs along the southern margin of the Yellow River. Little is known about the age and origin of this large (17,000 km 2 ) sand sea with a present annual precipitation of 200‐480 mm. Sand drift potentials indicated net capable winds for aeolian transport are from the northwest, though winds are stronger to north beyond the dune field than within the sand sea. Geomorphic and stratigraphic observations indicate that Holocene aeolian sand often drapes over bedrock and river terraces as a palimpsest landscape. Field investigations identified four stratigraphic sections with multiple aeolian sand units and palaeosols, with age control by optically stimulated luminescence (OSL) dating of quartz grains. Palaeosols are weakly developed, mostly accumulative A horizon with organic carbon content < 1% and reflect sand sheet deposition possibly in a steppe environment. Although sediments near river channels or former lakes might give old ages, the initial formation and age of the Kubuqi sand sea should be judged from the occurrence of the sandy palimpsest of the landscape that is OSL dated to the Holocene in general. The latest period of aeolian reactivation may be related to human activity associated with grazing and farming from lost cities in the Kubuqi Desert during the Han (206 B.C. – A.D. 220) and the Tang (A.D. 608 – 907) Dynasties. Also, variable discharge of the Yellow River with local diversions for irrigation and throughout the catchment resulted in possibly an increased supply of aeolian particles for dune field expansion in the past 2 ka. [ABSTRACT FROM AUTHOR]

Abstract: Sedimentary sequences occurring in desert dunes reflect changes in desert systems, and as such may contain signals useful for recognizing spatial and temporal changes of deserts and their response to regional or even global climate fluctuations. Geomorphological and palaeoenvironmental studies within the dune fields of the Asian middle-latitudes have provided some solid evidence for interpreting the history of these sand seas. Using the Hunshandake (Otindag) Sandy Land, a sandy area covered primarily by stabilized dunes and located in the semi-arid zone of eastern Inner Mongolia, China (Fig. 1), as an example, we studied the initiation and variation in the dune landscape in the eastern portion of the desert belt in northern China. On the basis of physical and biochemical indicators in the sediments and OSL chronology, we herein argue that this dune system in the middle latitudes of eastern Asia is much younger than previously assumed and that it has responded sensitively to climate change during the late Quaternary. Geological evidence from the Sandy Land suggests that most of the current dunes are of late Pleistocene or even Holocene age. Palaeosols intercalated in the aeolian sequences and their OSL chronology show that the climate of the Hunshandake was much wetter than today between 9.6 ka and 3 ka. This resulted in stabilization of the dunes in the eastern and central portions of the Sandy Land. Epochs of reworking or stabilization of the dunes are broadly consistent with the fluctuations in northern hemisphere solar radiation although with an obvious time lag. Because the increase rate of annual precipitation was not sufficient to fully stabilize the dunes in more arid part of the region, some active dunes persisted even during this long-lasting wetter epoch. We conclude that periods of Holocene dune stabilization due to palaeosol formation varied along the climate gradients across the various sandy lands of northern China, and in general it began earlier and lasted longer in the east than in the west. The general nature of the sandy lands and their counterparts in the western portion of the desert belt during the LGM and mid-Holocene climate optimum is discussed in comparison with their current states. [Copyright &y& Elsevier]