In the context of global research in snow-affected regions, research in the Australian Alps has been steadily catching up to the more established research environments in other countries. One area that holds immense potential for growth is hydrological modelling. Future hydrological modelling could be used to support a range of management and planning issues, such as to better characterise the contribution of the Australian Alps to flows in the agriculturally important Murray-Darling Basin despite its seemingly small footprint. The lack of recent hydrological modelling work in the Australian Alps has catalysed this review, with the aim to summarise the current state and to provide future directions for hydrological modelling, based on advances in knowledge of the Australian Alps from adjacent disciplines and global developments in the field of hydrologic modelling. Future directions proffered here include moving beyond the previously applied conceptual models to more physically based models, supported by an increase in data collection in the region, and modelling efforts that consider non-stationarity of hydrological response, especially that resulting from climate change.

Black carbon (BC) is a distinct type of carbonaceous aerosol that has a significant impact on the environment, human health, and climate. A non-BC material coating on BC can alter the mixing state of the BC particles, which considerably enhances the mass absorption efficiency of BC by directing more energy toward the BC cores (lensing effect). A lot of methods have been reported for quantifying the enhancement factor (Eabs), with diverse results. However, to the best of our knowledge, a comprehensive review specific to the quantification methods for Eabs has not been systematically performed, which is unfavorable for the evaluation of obtained results and subsequent radiative forcing. In this review, quantification methods are divided into two broad categories, direct and indirect, depending on whether experimental removal of the coating layer from an aged carbonaceous particle is required. The direct methods described include thermal peeling, solvent dissolution, and optical virtual exfoliation, while the indirect methods include intercept-linear regression fitting, minimum R squared, numerical simulation, and empirical value. We summarized the principles, procedures, virtues, and limitations of the major Eabs quantification methods and analyzed the current problems in the determination of Eabs. We pointed out what breakthroughs are needed to improve or innovate Eabs quantification methods, particularly regarding the need to avoid the influence of brown carbon, develop a broadband Eabs quantification scheme, quantify the Eabs values for the emissions of low-efficiency combustions, measure the Eabs of particles in a highhumidity environment, design a real-time monitor of Eabs by a proper combination of mature techniques, and make more use of artificial intelligence for better Eabs quantification. This review deepens the understanding of Eabs quantification methods and benefits the estimation of the contribution of BC to radiative forcing using climate models.

Groundwater (GW) is sensitive to climate change (CC), and the effects have become progressively more evident in recent years. Many studies have examined the effects of CC on GW quantity. Still, there is growing interest in assessing the qualitative impacts of CC, especially on GW temperature (GWT), and the consequences of these impacts. This study aimed to systematically review recently published papers on CC and GWT, determine the impacts of CC on GWT, and highlight the possible consequences. The Scopus and Web of Science databases were consulted, from which 144 papers were obtained. After an initial screening for duplicate papers, a second screening based on the titles and abstracts, and following an analysis of topic applicability to this subject after examining the full text, 44 studies were included in this review. The analysed scientific literature, published in 29 different journals, covered all five continents from 1995 to 2023. This review indicated that the subject of GWT variations due to CC is of global interest and has attracted significant attention, especially over the past two decades, with many studies adopting a multidisciplinary approach. A general increase in GWT was noted as a primary effect of CC (especially in urban areas); furthermore, the implications of this temperature increase for contaminants and GW-dependent ecosystems were analysed, and various applications for this increase (e.g. geothermal) were evaluated. This review highlights that GWT is vulnerable to CC and that the consequences can be serious and worthy of further investigation.

Significant progress in permafrost carbon science made over the past decades include the identification of vast permafrost carbon stocks, the development of new pan-Arctic permafrost maps, an increase in terrestrial measurement sites for CO2 and methane fluxes, and important factors affecting carbon cycling, including vegetation changes, periods of soil freezing and thawing, wildfire, and other disturbance events. Process-based modeling studies now include key elements of permafrost carbon cycling and advances in statistical modeling and inverse modeling enhance understanding of permafrost region C budgets. By combining existing data syntheses and model outputs, the permafrost region is likely a wetland methane source and small terrestrial ecosystem CO2 sink with lower net CO2 uptake toward higher latitudes, excluding wildfire emissions. For 2002-2014, the strongest CO2 sink was located in western Canada (median: -52 g C m-2 y-1) and smallest sinks in Alaska, Canadian tundra, and Siberian tundra (medians: -5 to -9 g C m-2 y-1). Eurasian regions had the largest median wetland methane fluxes (16-18 g CH4 m-2 y-1). Quantifying the regional scale carbon balance remains challenging because of high spatial and temporal variability and relatively low density of observations. More accurate permafrost region carbon fluxes require: (a) the development of better maps characterizing wetlands and dynamics of vegetation and disturbances, including abrupt permafrost thaw; (b) the establishment of new year-round CO2 and methane flux sites in underrepresented areas; and (c) improved models that better represent important permafrost carbon cycle dynamics, including non-growing season emissions and disturbance effects. Climate change and the consequent thawing of permafrost threatens to transform the permafrost region from a carbon sink into a carbon source, posing a challenge to global climate goals. Numerous studies over the past decades have identified important factors affecting carbon cycling, including vegetation changes, periods of soil freezing and thawing, wildfire, and other disturbance events. Overall, studies show high wetland methane emissions and a small net carbon dioxide sink strength over the terrestrial permafrost region but results differ among modeling and upscaling approaches. Continued and coordinated efforts among field, modeling, and remote sensing communities are needed to integrate new knowledge from observations to modeling and predictions and finally to policy. Rapid warming of northern permafrost region threatens ecosystems, soil carbon stocks, and global climate targets Long-term observations show importance of disturbance and cold season periods but are unable to detect spatiotemporal trends in C flux Combined modeling and syntheses show the permafrost region is a small terrestrial CO2 sink with large spatial variability and net CH4 source

Satellite-derived Land Surface Temperature (LST) dynamics have been increasingly used to study various geophysical processes. This review provides an extensive overview of the applications of LST in the context of global change. By filtering a selection of relevant keywords, a total of 164 articles from 14 international journals published during the last two decades were analyzed based on study location, research topic, applied sensor, spatio-temporal resolution and scale and employed analysis methods. It was revealed that China and the USA were the most studied countries and those that had the most first author affiliations. The most prominent research topic was the Surface Urban Heat Island (SUHI), while the research topics related to climate change were underrepresented. MODIS was by far the most used sensor system, followed by Landsat. A relatively small number of studies analyzed LST dynamics on a global or continental scale. The extensive use of MODIS highly determined the study periods: A majority of the studies started around the year 2000 and thus had a study period shorter than 25 years. The following suggestions were made to increase the utilization of LST time series in climate research: The prolongation of the time series by, e.g., using AVHRR LST, the better representation of LST under clouds, the comparison of LST to traditional climate change measures, such as air temperature and reanalysis variables, and the extension of the validation to heterogenous sites.

Glaciers are attracting increasing attention in the context of climate change, and glacier tourism has also become a popular tourist product. However, few studies have been conducted concerning the image of glacier tourism destinations. To address this gap in the literature, in this study, we extracted destination images from 138,709 visitor reviews of 107 glacier tourism destinations on TripAdvisor using latent Dirichlet allocation (LDA) topic modeling, identified destination image characteristics using salience-valence analysis (SVA), and analyzed the differences in glacier tourism destination image characteristics across seasons and regions. According to the findings, the image of a glacier tourism destination consists of 14 dimensions and 53 attributes, with landscapes and specific activities representing the core image and viewing location and necessity representing the unique image. We identified significant seasonal and regional differences in the image of glacier tourism destinations. Finally, we discussed the unique image of glacier tourism destinations, the reasons for differences in the images, and the characteristics of different glacier tourism regions. This research could assist in the scientific management of their core images by glacier tourism destinations, as well as in the rational selection of destinations and travel timing by glacier tourists.

A characteristic of frozen ground is a tendency to form banded sequences of particle-free ice lenses separated by layers of ice-infiltrated soil, which produce frost heave. In permafrost, the deformation of the ground surface caused by segregated ice harms engineering facilities and has considerable influences on regional hydrology, ecology, and climate changes. For predicting the impacts of permafrost degradation under global warming and segregated ice transformation on engineering and environmental, establishing appropriate mathematical models to describe water migration and ice behavior in frozen soil is necessary. This requires an essential understanding of water migration and segregated ice formation in frozen ground. This article reviewed mechanisms of water migration and ice formation in frozen soils and their model construction and introduced the effects of segregated ice on the permafrost environment included landforms, regional hydrological patterns, and ecosystems. Currently, the soil water potential has been widely accepted to characterize the energy state of liquid water, to further study the direction and water flux of water moisture migration. Models aimed to describe the dynamics of ice formation have successfully predicted the macroscopic processes of segregated ice, such as the rigid ice model and segregation potential model, which has been widely used and further developed. However, some difficulties to describe their theoretical basis of microscope physics still need further study. Besides, how to describe the ice lens in the landscape models is another interesting challenge that helps to understand the interaction between soil ice segregation and the permafrost environment. In the final of this review, some concerns overlooked by current research have been summarized which should be the central focus in future study.

Brown carbon is a hotspot in the field of atmospheric carbonaceous aerosol research. It has significant influence on regional radiative forcing and exerts climatic effects due to its apparent absorbance in the near ultraviolet-visible region. Brown carbon is mainly derived from incomplete combustion of biomass or coal, as well as secondary sources, such as a series of atmospheric photochemical reactions from volatile organic compounds. Although the composition of brown carbon is complex, high-resolution mass spectrometry, with its ultra-high mass resolution and precision, enables elucidation of the characteristics of the organic components of brown carbon at the molecular level. Here, high-resolution mass spectrometry combined with traditional analytical methods was used for the study of brown carbon. The development of high-resolution mass spectrometry for brown carbon separation is reviewed, as well as compositional analysis, source apportionment, and formation mechanism of brown carbon based on high-resolution data. In addition, the issues and prospects for the application of high-resolution mass spectrometry to evaluate brown carbon are discussed.

Knowledge of the thermal state of mountain permafrost has greatly increased since 2007 with the establishment of numerous new monitoring stations around the world. Data collected at these sites have pointed to longer-term changes in ground temperatures, which seem to have increased during the last two to three decades in cold permafrost, while in ground close to 0 degrees C the near-surface ice content has restricted warming and similar trends are not apparent. Modelling of mountain permafrost has developed greatly, driven by general circulation models or gridded temperature maps, through both predictive methods and spatial equilibrium and transient approaches. The spatial resolution of climate parameters, which is normally much coarser than the spatial heterogeneity of alpine environments, presents a major problem for modelling studies. This is a fundamental challenge for future research. Copyright (c) 2013 John Wiley & Sons, Ltd.

The climatic changes on earth may have serious implications for the carbon (C) cycle in the terrestrial Arctic throughout the 21st century. Arctic vegetation takes up carbon dioxide (CO2) from the atmosphere producing biomass. In a cold and often moist soil environment, dead organic matter is preferentially preserved as soil organic matter (SOM) due to the inhibition of decomposition processes. However, viable soil microbes exhale huge amounts of CO2 and methane (CH4) annually. Hence, Arctic ecosystems exhibit annual fluxes of both carbon-based (CO2 and CH4) greenhouse gases (GHGs) that are in an order of magnitude of millions of tons. Rising Arctic temperatures lead to the degradation of much of today's permafrost in the long run. As a result, large quantities of frozen SOM may become available for decomposers, and GHGs that are entrapped in permafrost may be released. At the same time, warming tends to stimulate the growth, development, and reproduction of many Arctic plants, at least transiently. The present northward migration of boreal shrubs and trees into southern tundra areas may be amplified by that, increasing the ecosystems' gross primary production and, thus, their C sequestration. On the other hand, rising temperatures boost SOM decomposition and microbial respiration rates. In general, soil temperature and soil moisture are key environmental variables to control the, intensity of aerobic and anaerobic respiration by microbes, and autotrophic respiration by plants. On the basis of published data on Arctic CO2 and CH4 fluxes, the calculations on the terrestrial C-based Arctic GHG balance made in this review reveal a current annual GHG exchange that ranges between a weak storage of <= 225 Tg CO2 equivalent (eq.) y(-1) and a huge release of 1990 Tg CO2 eq. y(-1). Hence, the Arctic GHG balance does apparently already contribute positively to the climatic changes at present. Regarding the future, the relative development of the uptake and release of CO2 and CH4 by northern ecosystems is fundamental to the overall GHG status of the Arctic under scenarios of continued climate change.