Atmospheric dust activity poses significant environmental and socioeconomic challenges in East Asia. This study investigates multi-timescale variations of spring dust and their drivers in the Jiziwan region (JZW) of the Yellow River basin and two major source areas-the Mongolian Gobi region (MGR) and the Taklimakan Desert region (TDR)-using station observations (1956-2025) and MERRA-2 reanalysis data. Results show that interannual spring dust fluctuations in JZW align significantly with those in MGR, while its long-term trend corresponds more closely with TDR. On interannual timescales, JZW dust variability is modulated by phase shifts in the preceding winter's Arctic Oscillation (AO), which persistently influence Siberian snow cover and, in turn, perturb mid-latitude tropospheric circulation and local surface conditions, thereby modulating dust activity. On multidecadal timescales, the observed long-term weakening trend in JZW spring dust activity is associated with declining Arctic sea ice concentration during the prior winter. Persistent sea ice anomalies alter the polar-midlatitude thermal gradient, driving large-scale circulation adjustments across Eurasia. These changes systematically affect the East Asian westerlies and near-surface wind speeds, ultimately reducing regional dust emissions. By distinguishing the drivers operating on different temporal scales, this study offers new insights into the mechanisms shaping East Asian dust activity under changing climate conditions.

Geological evidence and numerical simulations indicate that the uplift of the Tibetan Plateau (TP) contributed to the formation of inland Asian deserts, and that the dust activity of the deserts affected local atmospheric circulation and the hydrological cycle through dust-radiation interactions. In this study, we conducted a series of sensitivity experiments using a global climate model to evaluate the impact of three forcing factors-TP terrain, dust direct effect, and dust-ice cloud interaction-on the climate evolution of inland Asia. The results show that TP uplift has a significant impact on drought in inland Asia (-175.5 +/- 44.1 mm per year) by blocking water vapor transport from westerly winds through the plateau's dynamical effect throughout the year and inducing compensatory downdrafts due to the plateau's thermal effect in summer and autumn. The dust effect intensifies the regional drought by -27.7 +/- 30.7 mm per year (particularly in spring and summer), mainly by suppressing atmospheric vertical convection through altering cloud microphysical processes. Our results suggest that the dust-ice cloud interaction provides a positive feedback mechanism for inland Asian aridity induced by the TP uplift.

Multiple lines of observational evidence have indicated a significant wetting over the arid and semi-arid Northwest China (NWC) during recent decades, coinciding with a simultaneous sharp decline of dust events. Although recent studies have attributed NWC wetting to different anthropogenic and natural forcings, the mechanisms are not definitive and the regional wetting has been greatly underestimated in the Coupled Model Intercomparison Project historical simulations. Based on sensitivity experiments with different dust emission amounts using the NCAR Community Atmospheric Model version 5 (CAM5), here we find that decreasing dusts exert significant impacts on mixed-phase clouds through reducing the concentration of ice nucleating particles, increase the NWC precipitation and thus induce regional wetting through enhancing convection precipitation. A possible convection invigoration mechanism whereby the atmospheric vertical temperature gradient and convective instability are strengthened by reduced dusts, leading to convection invigoration and increased precipitation. These results are reinforced by simulations over the dust region in North Africa where mixed-phase and ice clouds are rare and reduced dusts do not increase precipitation. This study highlights the possible mechanism of dust-ice cloud interactions in recent NWC wetting and future regional climate change.

The impacts of topographic uplift in different areas of the Tibetan Plateau (TP) on the arid climate and dust cycle in the sandy areas on the north and south sides of the plateau are studied using a regional climate model (RCM) by comparing numerical experiments on the uplift of the Pamirs and the northern TP. Simulation results based on tectonic geological records can be used to explain the differences in drought evolution in different areas around the TP. The results show that: (1) The mechanical blocking effect caused by the uplift of the Pamirs has mainly intensified the aridification and desertification of the Taklimakan Desert since the Pliocene, and its uplift has blocked the water vapor channel in the west side of Tarim Basin, causing a 50% reduction in the annual precipitation (mainly winter precipitation) and a 10-30% increase in the atmospheric dust loading in the Taklimakan Deserts. (2) The uplift of the northern Tibetan Plateau mainly intensifies the aridification of the Thar Desert. The uplift of the northern TP controls the position and intensity of the subtropical high center at 700 hPa in the Thar Desert, causing a 50% reduction in summer and annual precipitation and increase in the atmospheric dust loading in the Thar Desert. (3) The aridification of the Gobi Desert and Loess Plateau since the Miocene is also related to the uplift of the northern TP. The uplifting suppresses the East Asian summer monsoon (EASM), causing a 30-50% reduction in summer precipitation in the Gobi Desert and Loess Plateau. Drought further causes a 10-20% increase in the dust loading in the above areas. (4) In view of the limited geological evidence of remarkable tectonic uplift in the northern TP and the Pamirs since the Miocene and Pliocene respectively and based on the current numerical simulation results, it is speculated that the formation of the Thar Desert should be earlier than the Taklimakan Desert.

The dynamic and thermal effects of the Tibetan Plateau (TP) on the precipitation in the Asian arid and monsoon regions were investigated using three numerical experiments-one using real topography, one with the whole TP removed, and one with sensible heat turned off over the TP. The results show that there are strong seasonal and regional differences in the dynamic and thermal effects of the TP on the precipitation in the Asian arid regions. The dynamic effect dominated the decrease in winter precipitation by blocking the westerly, while the thermal effect dominated the decrease in summer precipitation due to the TP-induced compensation downdraft in Central Asia and arid East Asia. The thermal effect dominated and accounted for 60% of the decrease in summer precipitation in West Asia. The results also show that both the dynamic and thermal effects of TP exhibit a more salient influence on the East Asian monsoon region than the South Asian monsoon region. The thermal effect dominated and accounted for 40% of the increase in summer precipitation due to intensification of the summer monsoon, while the dynamic effect dominated and accounted for 80% of the decrease in winter precipitation due to the northeast wind anomaly in the northern East Asian monsoon region. The anomalous wind can reach to the coast of South China and form frontal precipitation in the southern East Asian monsoon region in winter. The thermal effect dominated and accounted for 80% of the increase in precipitation in the pre-monsoon period due to intensification of the Asian summer monsoon.

The transport of dust aerosol in East Asia is affected by the East Asian winter monsoon (EAWM) and westerly circulation both for modern and geological periods. There are obvious seasonal changes in the intensity and range of EAWM and westerly jet; however, their impacts and relative contributions to East Asian dust transmission are still unclear. In this study, we use Regional Climate Model 4 (RegCM4) to simulate the changes in the East Asian dust cycle under present conditions, assessing the effects of EAWM and westerly jet on dust transport. The results show that the dust at the upper level is mainly transported by the westerly circulation, while that of the lower layer is mainly transported by the EAWM. In March, the westerly jet is located on the south side of the Tibet Plateau and the high-level dust aerosol is transmitted eastward to the northern Pacific. Low-level dust is transmitted to the southeastern China with the influence of EAWM. With the northward shift of the westerly jet, the control range of the westerly winds increases in May and their correlations are weakened. In contrary, the impact of EAWM on the lower layer dust is enhanced. Due to the strengthened interaction between the westerly winds and the EAWM, they can both affect the middle-level dust transmission. The effect of EAWM is sensitive to the dust particle sizes. Under the action of EAWM, fine-grained dust is transmitted far away, while coarse-grained dust is limited to the vicinity of the source area. Once the dust is carried to the westerly layer, the influence of westerly winds on the transmission of different particle sizes dust is similar.

Although variations of atmospheric dust aerosols emitted from different sources within Asia have been studied separately in previous research, the characteristics and causes of these changes have not been fully explored. This study used the Modern-Era Retrospective Analysis for Research and Applications Version 2 (MERRA-2) data set for 1980-2016 to compare seasonal and interannual variations of atmospheric dust aerosols between mid-and low-latitude sources of Asia and explore the reasons for these variations. The seasonal variation of atmospheric dust aerosols in mid-latitude sources was different from that of low-latitude sources. The column burden of dust aerosols in the mid-latitude sources (including East and Central Asia) reached their maximum in spring, and accounted for about 37% and 33% of their annual total load, respectively. The maximum dust aerosols in spring in the Central Asia sources resulted from multiple factors such as soil wetness, snow depth, and vertical wind shear, but they were negatively correlated with soil wetness on the interannual scale (r = - 0.65). The maximum dust aerosol burden in spring in the East Asia sources resulted from vertical wind shear in the lower troposphere, and showed a positive correlation with the interannual change of dust aerosols in this source region (r = 0.51). However, the column burden of dust aerosols in the low-latitude sources (including South and West Asia) reached their maximum in summer, and accounted for about 41% and 37% of their annual total load, respectively. The maximum dust aerosols of summer in the low-latitude sources also resulted from vertical wind shear in the lower troposphere with correlation coefficients of 0.50 and 0.73 in the South and West Asia sources, respectively. The present results may help in further understanding the formation and change of Asian dust aerosols.

利用WRF模式,通过数值模拟试验研究了夏季太湖的局地气候效应,揭示了太湖对局地降水、温度等气象要素的影响,并探讨了内在的物理机制.结果表明:太湖主要在局地尺度上引起夏季地面气温降低和降水的减少,影响强度从湖区向周边地区逐渐减弱;太湖引起的夏季降水减少主要来源于对对流性降水的减弱作用;太湖对湖区及邻近区域夏季地面气温和降水的影响表现出明显的日变化特征,白天影响程度明显强于夜间且在午后的影响最强;太湖在午后引起湖区及邻近地区低层大气显著降温和异常辐散,抑制了该区域的大气对流活动并引起对流降水的明显减少,进而造成夏季太湖及邻近地区降水的减少.

Based on the geological evidence that the northern Tibetan Plateau (NTP) had an uplift of a finite magnitude since the Miocene and the major Asian inland deserts formed in the early Pliocene, a regional climate model (RegCM4.1) with a horizontal resolution of 50 km was used to explore the effects of the NTP uplift and the related aridification of inland Asia on regional climate. We designed three numerical experiments including the control experiment representing the present-day condition, the high-mountain experiment representing the early Pliocene condition with uplifted NTP but absence of the Asian inland deserts, and the low-mountain experiment representing the mid-Miocene condition with reduced topography in the NTP (by as much as 2400 m) and also absence of the deserts. Our simulation results indicated that the NTP uplift caused significant reductions in annual precipitation in a broad region of inland Asia north of the Tibetan Plateau (TP) mainly due to the enhanced rain shadow effect of the mountains and changes in the regional circulations. However, four mountainous regions located in the uplift showed significant increases in precipitation, stretching from the Pamir Plateau in the west to the Qilian Mountains in the east. These mountainous areas also experienced different changes in the rainfall seasonality with the greatest increases occurring during the respective rainy seasons, predominantly resulted from the enhanced orographically forced upwind ascents. The appearance of the major deserts in the inland Asia further reduced precipitation in the region and led to increased dust emission and deposition fluxes, while the spatial patterns of dust deposition were also changed, not only in the regions of uplift-impacted topography, but also in the downwind regions. One major contribution from this study is the comparison of the simulation results with 11 existing geological records representing the moisture conditions from Miocene to Pliocene. The comparisons revealed good matches between the simulation results and the published geological records. Therefore, we conclude that the NTP uplift and the related formation of the major deserts played a controlling role in the evolution of regional climatic conditions in a broad region in inland Asia since the Miocene. (C) 2015 Elsevier Ltd. All rights reserved.