Glacier Runoff Variation Since 1981 in the Upper Naryn River Catchments, Central Tien Shan

Water resources in Central Asia strongly depend on glaciers, which in turn adjust their size in response to climate variations. We investigate glacier runoff in the period 1981–2019 in the upper Naryn basin, Kyrgyzstan. The basins contain more than 1,000 glaciers, which cover a total area of 776 km2. We model the mass balance and runoff contribution of all glaciers with a simplified energy balance melt model and distributed accumulation model driven by ERA5 LAND re-analysis data for the time period of 1981–2019. The results are evaluated against discharge records, satellite-derived snow cover, stake readings from individual glaciers, and geodetic mass balances. Modelled glacier volume decreased by approximately 6.7 km3 or 14%, and the majority of the mass loss took place from 1996 until 2019. The decreasing trend is the result of increasingly negative summer mass balances whereas winter mass balances show no substantial trend. Analysis of the discharge data suggests an increasing runoff for the past two decades, which is, however only partly reflected in an increase of glacier melt. Moreover, the strongest increase in discharge is observed in winter, suggesting either a prolonged melting period and/or increased groundwater discharge. The average runoff from the glacierized areas in summer months (June to August) constitutes approximately 23% of the total contributions to the basin’s runoff. The results highlight the strong regional variability in glacier-climate interactions in Central Asia.

The international tephra research group ‘Commission on Tephrochronology’ and its activities – the first 60 years

Modern tephra studies per se began almost 100 years ago (in the late 1920s) but the first collective of tephrochronologists, with a common purpose and nascent global outlook, was not formed until 7 September, 1961, in Warsaw, Poland. On that date, the inaugural ‘Commission on Tephrochronology’ (COT) was ratified under the aegis of the International Union for Quaternary Research (INQUA). COT’s formation can be attributed largely to the leadership of Kunio Kobayashi of Japan, the commission’s president for its first 12 years. We were motivated to record COT’s heritage for posterity and also because the discipline of tephrochronology, including the study of cryptotephras, continues to grow globally at a significant rate. This is recognition of tephrochronology as both a unique correlational and age-equivalent dating method, and as a complementary method in other fields, such as volcanology, in which tephra research has been employed to develop eruption histories and hazards and to help understand volcano-climate interactions. In this article, we review the history of COT (which also functioned under other names, abbreviated as COTS, CEV, ICCT, COTAV, SCOTAV, INTAV) under the umbrella of INQUA for 53 of the last 60 years, or under IAVCEI (International Association of Volcanology and Chemistry of the Earth’s Interior) for seven of the last 60 years, including since 2019. We describe the development of the commission and its subsequent activities that include organising nine specialist tephra-field meetings in seven different countries, numerous conference sessions or workshops, and generating tephra-themed issues of journals/books or specialist internet documents or websites. The commission began to prosper after 1987 when key changes occurred, and it has blossomed further, especially in the past decade or so as an entire new cohort of specialists has emerged alongside new analytical and dating techniques to become a vibrant global group today. We name 29 elected officers involved with COT since 1961 and their roles, and 15 honorary life members. We also document the aims of the commission and conclude by evaluating its legacies and current and future work.

The Response of Brewster Glacier to Five Decades of Climate

<p>Small perturbations in climate can produce measurable changes to the size of a glacier. Documenting such changes is important for quantifying water storage changes, and understanding glacier-climate interactions. By using all available geodetic data, such as Landsat imagery, Shuttle Radar Topography Mission, GNSS and photogrammetric techniques, as well as ground penetrating radar for the construction of a bed DEM, it is found that Brewster Glacier decreased in volume from 1967 to 2017, losing ∼56% of its volume, with a period of volume increase of ∼10% from 1986 to 1997. The overall pattern of geodetic mass balance is similar to the glaciological mass balance record, however, the geodetic method tends to show more negative values by an average of ∼0.6 m w.e. Contrary to many other New Zealand glaciers, which experienced an advance from 1983 to 2008, Brewster Glacier continued to retreat by 390 m during the study period, at an average rate of 7.8 m a⁻¹, but at a significantly reduced rate of ∼2 m a⁻¹ from 1997 until 2005. By comparing the records of Brewster Glacier and Fox and Franz Josef glaciers, we explore the differences in response and reaction times resulting from glacier area-altitude distribution, and climatic setting. Furthermore, DEMs produced by this study are now available for use by a New Zealand wide glacier monitoring programme.</p>

The Response of Brewster Glacier to Five Decades of Climate

<p>Small perturbations in climate can produce measurable changes to the size of a glacier. Documenting such changes is important for quantifying water storage changes, and understanding glacier-climate interactions. By using all available geodetic data, such as Landsat imagery, Shuttle Radar Topography Mission, GNSS and photogrammetric techniques, as well as ground penetrating radar for the construction of a bed DEM, it is found that Brewster Glacier decreased in volume from 1967 to 2017, losing ∼56% of its volume, with a period of volume increase of ∼10% from 1986 to 1997. The overall pattern of geodetic mass balance is similar to the glaciological mass balance record, however, the geodetic method tends to show more negative values by an average of ∼0.6 m w.e. Contrary to many other New Zealand glaciers, which experienced an advance from 1983 to 2008, Brewster Glacier continued to retreat by 390 m during the study period, at an average rate of 7.8 m a⁻¹, but at a significantly reduced rate of ∼2 m a⁻¹ from 1997 until 2005. By comparing the records of Brewster Glacier and Fox and Franz Josef glaciers, we explore the differences in response and reaction times resulting from glacier area-altitude distribution, and climatic setting. Furthermore, DEMs produced by this study are now available for use by a New Zealand wide glacier monitoring programme.</p>

Understanding Past and Present Vegetation Dynamics using the Palynological Approach: An Introductory Discourse

Palynology is a multi-disciplinary field of science that deals with the study and application of extinct, [fossilised] and extant palynomorphs (pollen and spore) and other related microscopic biological entities in the environment. It is divided into palaeo- and actuo-palynology, and provides substantial proxies to understanding past and present vegetation dynamics respectively. With reference to the two geological principles of uniformitarianism and of the evolution of fauna/flora, the distribution of plant indicators across ecological zones, palynomorph morphology and pollen analysis, palynology can be used to identify the change in past and present local and regional vegetation and climate and humans impact on the environment. Other supportive areas of endeavour like radiocarbon dating, sedimentology, taphonomic processes and geomorphology can be used to triangulate inferences drawn from palynological data. Palynomorphs are made of outer cell walls embedded with an inert, complex and resistant biopolymeric signature (called sporopollenin) which helps to facilitate long term preservation in different environmental matrices under favourable conditions, hence its widespread applicability. Palynology have proven to very reliable in reconstructing past vegetation, decrypting essential honeybee plants and understanding the impact of climate on plant population using pollen analysis, for which is the basis for the application of palynology in environmental studies. The application of palynology in climate, vegetation and anthropogenic studies begins with the selection of matrix (sediments from lake, river, ocean, excavation, relatively intact soil profile, bee products), coring or collection of samples, subjection to a series of chemically aided digestion, separation, physical filtration, decanting, accumulating of palynomorphs, microscopic study and ends with the interpretation of recovered information. Literature review on the application of palynology for understanding vegetation and climate interactions is presented in this paper.

Redox Heterogeneity Entangles Soil and Climate Interactions

Interactions between soils and climate impact wider environmental sustainability. Soil heterogeneity intricately regulates these interactions over short spatiotemporal scales and therefore needs to be more finely examined. This paper examines how redox heterogeneity at the level of minerals, microbial cells, organic matter, and the rhizosphere entangles biogeochemical cycles in soil with climate change. Redox heterogeneity is used to develop a conceptual framework that encompasses soil microsites (anaerobic and aerobic) and cryptic biogeochemical cycling, helping to explain poorly understood processes such as methanogenesis in oxygenated soils. This framework is further shown to disentangle global carbon (C) and nitrogen (N) pathways that include CO2, CH4, and N2O. Climate-driven redox perturbations are discussed using wetlands and tropical forests as model systems. Powerful analytical methods are proposed to be combined and used more extensively to study coupled abiotic and biotic reactions that are affected by redox heterogeneity. A core view is that emerging and future research will benefit substantially from developing multifaceted analyses of redox heterogeneity over short spatiotemporal scales in soil. Taking a leap in our understanding of soil and climate interactions and their evolving influence on environmental sustainability then depends on greater collaborative efforts to comprehensively investigate redox heterogeneity spanning the domain of microscopic soil interfaces.