Study area: Urumqi Glacier No.1 Catchment in central Asia. Study focus: Chemical weathering at the basin scale is important process for understanding the feedback mechanism of the carbon cycle and climate change. This study mainly used the actual sampling data in 2013, 2014, and 2016, and the first collection from the literature in same catchment to analyze the seasonal and interannual characteristics of meltwater runoff, as well as cation denudation rate (CDR). New hydrological insights for the study region: The dominant ions of meltwater runoff are Ca2 +, HCO3- , and SO42-, which are mainly derived from calcite dissolution, feldspar weathering and sulfide oxidation. Meltwater runoff at Urumqi Glacier No.1 has higher concentrations of Ca2+ and lower concentrations of HCO3- than that from glaciers in Asia. Compared to 2006 and 2007, cation concentrations increased in 2013 and 2014, while SO42- concentration decreased. The daily ion concentration has seasonality and exhibits a negative relationship with discharge. Daily CDR is positively related to discharge and temperature. Annual CDR values range from 12.34 to 19.04 t/ km2/yr in 2013, 2014, and 2016, which are 1-1.7 times higher than those in 2006 and 2007 and higher than some glaciers in Asia. These results indicate that chemical weathering rate in the Urumqi Glacier No.1 catchment has increased with climate warming, and it is stronger than that of some glaciers in the Tibetan Plateau and surroundings.

Study area: Urumqi Glacier No.1 Catchment in central Asia. Study focus: Chemical weathering at the basin scale is important process for understanding the feedback mechanism of the carbon cycle and climate change. This study mainly used the actual sampling data in 2013, 2014, and 2016, and the first collection from the literature in same catchment to analyze the seasonal and interannual characteristics of meltwater runoff, as well as cation denudation rate (CDR). New hydrological insights for the study region: The dominant ions of meltwater runoff are Ca2 +, HCO3- , and SO42-, which are mainly derived from calcite dissolution, feldspar weathering and sulfide oxidation. Meltwater runoff at Urumqi Glacier No.1 has higher concentrations of Ca2+ and lower concentrations of HCO3- than that from glaciers in Asia. Compared to 2006 and 2007, cation concentrations increased in 2013 and 2014, while SO42- concentration decreased. The daily ion concentration has seasonality and exhibits a negative relationship with discharge. Daily CDR is positively related to discharge and temperature. Annual CDR values range from 12.34 to 19.04 t/ km2/yr in 2013, 2014, and 2016, which are 1-1.7 times higher than those in 2006 and 2007 and higher than some glaciers in Asia. These results indicate that chemical weathering rate in the Urumqi Glacier No.1 catchment has increased with climate warming, and it is stronger than that of some glaciers in the Tibetan Plateau and surroundings.

Insights into the impacts of freeze-thaw processes on soil microorganisms and their related functions in permafrost regions are crucial for assessing ecological consequences imposed by the shifts in freeze-thaw patterns. Through in-situ investigations on seasonal freeze-thaw processes in the active layer of permafrost in the Qinghai-Tibet Plateau, we found that microbial richness was higher and positively correlated with soil multifunctionality during the freeze-thaw stage (freezing and thawing periods) compared to the non-freeze-thaw stage (completely frozen and thawed periods). This relationship resulted from the higher microbial stability, which was highly consistent with the lower complexity, more keystone taxa, and greater robustness of networks. Although freeze-thaw strength exacerbated the greenhouse effect on climate, it was alleviated by the enhancement of diversity-soil multifunctionality relationship. These findings have substantial implications for exploring the responses of microbial-mediated soil multifunctionality and greenhouse effect in alpine permafrost to more drastic variations of freeze-thaw processes under future warming.

In context with the scientific evidence of aerosol deposition induced snow and glacier melt, this paper provides baseline information about the spatiotemporal variability of aerosols and snow-ice chemistry filling the data and knowledge gap over the western Himalaya, India based on recently published paper [ 1 ]. A systematic approach was employed that entailed analysis of aerosol variability over four decades using MERRA-2 (Modern-Era Retrospective analysis for Research and Applications) data over five major mountain ranges in the western Himalaya. Further, data about nine physicochemical parameters was generated over three selected glaciers in the study area. HYSPLIT (HYbrid Single Particle Lagrangian Integrated Trajectory) model simulated air mass sources at weekly intervals. This dataset is valuable for future investigations aimed at understanding and characterizing the impacts of light-absorbing impurities on radiative forcing, albedo changes, snow-melt, glacier recession and wa- ter quality in the western Himalaya. (c) 2024 Published by Elsevier Inc. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)

In the context of global warming, increasingly widespread and frequent freezing and thawing cycles (FTCs) will have profound effects on the biogeochemical cycling of soil carbon and nitrogen. FTCs can increase soil greenhouse gas (GHG) emissions by reducing the stability of soil aggregates, promoting the release of dissolved organic carbon, decreasing the number of microorganisms, inducing cell rupture, and releasing carbon and nitrogen nutrients for use by surviving microorganisms. However, the similarity and disparity of the mechanisms potentially contributing to changes in GHGs have not been systematically evaluated. The present study consolidates the most recent findings on the dynamics of soil carbon and nitrogen, as well as GHGs, in relation to FTCs. Additionally, it analyzes the impact of FTCs on soil GHGs in a systematic manner. In this study, particular emphasis is given to the following: (i) the reaction mechanism involved; (ii) variations in soil composition in different types of land (e.g., forest, peatland, farmland, and grassland); (iii) changes in soil structure in response to cycles of freezing temperatures; (iv) alterations in microbial biomass and community structure that may provide further insight into the fluctuations in GHGs after FTCs. The challenges identified included the extension of laboratory-scale research to ecosystem scales, the performance of in-depth investigation of the coupled effects of carbon, nitrogen, and water in the freeze-thaw process, and analysis of the effects of FTCs through the use of integrated research tools. The results of this study can provide a valuable point of reference for future experimental designs and scientific investigations and can also assist in the analysis of the attributes of GHG emissions from soil and the ecological consequences of the factors that influence these emissions in the context of global permafrost warming.

Remote region is normally considered a receptor of long-range transported pollutants. Monitoring stations are important platforms for investigating the atmospheric environment of remote regions. However, the potential contribution of very local sources around these stations may produce important influences on its atmospheric environment, which is still barely studied. In this study, major ions of precipitation were investigated simultaneously at a typical remote station (Nam Co station) and other sites nearby on the Tibetan Plateau (TP) - the so-called The Third Pole in the world. The results showed that despite low values compared to those of other remote regions, the concentrations of major ions in precipitation of Nam Co station (e.g., Ca2+: 32.71 mu eq/L; SO42- : 1.73 mu eq/L) were significantly higher than those at a site around 2.2 Km away ( Ca2+: 11.47 mu eq/L; SO42- : 0.64 mu eq/L). This provides direct evidence that atmospheric environment at Nam Co station is significantly influenced by mineral dust and pollutants emitted from surface soil and anthropogenic pollutants of the station itself. Therefore, numbers of other related data reported on the station are influenced. For example, the aerosol concentration and some anthropogenic pollutants reported on Nam Co station should be overestimated. Meanwhile, it is suggested that it is cautious in selecting sites for monitoring the atmospheric environment at the remote station to reduce the potential influence from local sources.

This study reviews the available and published knowledge of the interactions between permafrost and groundwater. In its content, the paper focuses mainly on groundwater recharge and discharge in the Arctic and the Qinghai-Tibet Plateau. The study revealed that the geochemical composition of groundwater is site-specific and varies significantly within the depth of the aquifers reflecting the water-rock interactions and related geological history. All reviewed studies clearly indicated that the permafrost thaw causes an increase in groundwater discharge on land. Furthermore, progressing climate warming is likely to accelerate permafrost degradation and thus enhance hydrological connectivity due to increased subpermafrost groundwater flow through talik channels and higher suprapermafrost groundwater flow. In the case of submarine groundwater discharge (SGD), permafrost thaw can either reinforce or reduce SGD, depending on how much pressure changes affecting the aquifers will be caused by the loss of permafrost. Finally, this comprehensive assessment allowed also for identifying the lack of long-term and interdisciplinary in situ measurements that could be used in sophisticated computational simulations characterizing the current status and predicting groundwater flow and permafrost dynamics in the future warmer climate.

Permafrost regions are under particular pressure from climate change resulting in wide-spread landscape changes, which impact also freshwater chemistry. We investigated a snapshot of hydrochemistry in various freshwater environments in the lower Kolyma river basin (North-East Siberia, continuous permafrost zone) to explore the mobility of metals, metalloids and non-metals resulting from permafrost thaw. Particular attention was focused on heavy metals as contaminants potentially released from the secondary source in the permafrozen Yedoma complex. Permafrost creeks represented the Mg-Ca-Na-HCO3-Cl-SO4 ionic water type (with mineralisation in the range 600-800 mg L-1), while permafrost ice and thermokarst lake waters were the HCO3-Ca-Mg type. Multiple heavy metals (As, Cu, Co, Mn and Ni) showed much higher dissolved phase concentrations in permafrost creeks and ice than in Kolyma and its tributaries, and only in the permafrost samples and one Kolyma tributary we have detected dissolved Ti. In thermokarst lakes, several metal and metalloid dissolved concentrations increased with water depth (Fe, Mn, Ni and Zn - in both lakes; Al, Cu, K, Sb, Sr and Pb in either lake), reaching 1370 mu g L-1 Cu, 4610 mu g L-1 Mn, and 687 mu g L-1 Zn in the bottom water layers. Permafrost-related waters were also enriched in dissolved phosphorus (up to 512 mu g L-1 in Yedoma-fed creeks). The impact of permafrost thaw on river and lake water chemistry is a complex problem which needs to be considered both in the context of legacy permafrost shrinkage and the interference of the deepening active layer with newly deposited anthropogenic contaminants.

Aerosol mixtures, which are still unclear in current knowledge, may cause large uncertainties in aerosol climate effect assessments. To better understand this research gap, a well-developed online coupled regional climate-chemistry model is employed here to investigate the influences of different aerosol mixing states on the direct interactions between aerosols and the East Asian summer monsoon (EASM). The results show that anthropogenic aerosols have high-level loadings with heterogeneous spatial distributions in East Asia. Black carbon aerosol loading accounts for more than 13% of the totals in this region in summer. Thus, different aerosol mixing states cause very different aerosol single scattering albedos, with a variation of 0.27 in East Asia in summer. Consequently, the sign of the aerosol instantaneous direct radiative forcing at the top of the atmosphere is changed, varying from - 0.95 to + 1.50 W/m(2) with increasing internal mixing aerosols. The influence of aerosol mixtures on regional climate responses seems to be weaker. The EASM circulation can be enhanced due to the warming effect of anthropogenic aerosols in the lower atmosphere, which further induces considerable aerosol accumulation associated with dynamic field anomaly, decrease in rainfall and so on, despite aerosol mixtures. However, this interaction between aerosols and the EASM will become more obvious if the aerosols are more mixed internally. Additionally, the differences in aerosol-induced EASM anomalies during the strongest and weakest monsoon index years are highly determined by the aerosol mixing states. The results here may further help us better address the environmental and climate change issues in East Asia.

Runoff processes in glacier and paramo catchments in the Andean region are of interest as they are vitally important to serve the water needs of surrounding communities. Particularly in Northern Ecuador, the runoff processes are less well-known due to the high variability of precipitation, young volcanic ash soil properties, soil moisture dynamics and other local factors. Previous studies have shown that the melting of glaciers contributes to runoff generation and that the paramo ecosystem plays an important role in regulating runoff during periods of low precipitation. Data collection and experimental investigations were carried out in a catchment of 15.2 km(2) and altitude ranging between 4000 and 5700 m above sea level. Environmental tracers and hydrochemical catchment characterization were used for identifying runoff sources and their respective contributions during dry and wet conditions. Dry conditions are defined as periods where precipitation was absent for at least three consecutive days and wet conditions imply rainfall events. This study highlights the importance of the paramo on contributing to total runoff during baseflow (70% of total runoff) and the capacity of the paramo to dissipate the stream energy and buffer the peak flow during rainfall conditions. Electrical conductivity together with stable isotopes were identified as conservative tracers that characterize the end-member concentrations.