Climate Response of Larch and Birch Forests across an Elevational Transect and Hemisphere-Wide Comparisons, Kamchatka Peninsula, Russian Far East

Kamchatka’s forests span across the peninsula’s diverse topography and provide a wide range of physiographic and elevational settings that can be used to investigate how forests are responding to climate change and to anticipate future response. Birch (Betula ermanii Cham.) and larch (Larix gmelinii (Rupr.) Kuzen) were sampled at eight new sites and together with previous collections were compared with monthly temperature and precipitation records to identify their climate response. Comparisons show that tree-ring widths in both species are primarily influenced by May through August temperatures of the current growth year, and that there is a general increase in temperature sensitivity with altitude. The ring-width data for each species were also combined into regional chronologies. The resulting composite larch chronology shows a strong resemblance to a Northern Hemisphere (NH) tree-ring based temperature reconstruction with the larch series tracking NH temperatures closely through the past 300 years. The composite birch ring-width series more closely reflects the Pacific regional coastal late summer temperatures. These new data improve our understanding of the response of forests to climate and show the low frequency warming noted in other, more continental records from high latitudes of the Northern Hemisphere. Also evident in the ring-width record is that the larch and birch forests continue to track the strong warming of interior Kamchatka

Annual Sedimentary Record From Lake Donguz-Orun (Central Caucasus) Constrained by High Resolution SR-XRF Analysis and Its Potential for Climate Reconstructions

Bottom sediments of the proglacial Lake Donguz-Orun situated at ∼2500 m a.s.l. in the Elbrus Region (Central Caucasus) reveal regular laminae, characteristic of proglacial varved lakes. This is the first laminated sediment sequence recorded in the region. However, visual counting of the layers was restricted due to partial indistinctness of the lamination. In order to confirm the annual sedimentary cyclicity and proceed with annually resolved data, in addition to the visual identification we used high-resolution geochemical markers. The upper 160 mm of the sediment core were scanned at 200 μm intervals using synchrotron radiation X-ray fluorescence analysis (SR-XRF). Additional ultrahigh resolution scanning at 30 μm increments was employed for the upper 20 mm of the core. The Rb/Sr and Zr/Rb ratios are interpreted to record annual changes in grain-size. Based on this geochemical assessment, we identified 88 annual layers covering the interval between 1922 and 2010, while visually we have been able to identify between 70 and 100 layers. The correctness of the geochemical results is confirmed by mean accumulation rates assessed by 137Cs and 210Pb dating. Cross-correlation between the ring width of local pine chronology and the layer thickness, identified as a distance between the annual Rb/Sr peaks, allowed for the accurate dating of the uppermost preserved year of the sediment sequence (AD 2010). Annually averaged elemental data were then compared with regional meteorological observations, glacier mass balance and tree-ring chronologies. The comparison revealed notable conformities: content of bromine is positively correlated with annual temperatures (r = 0.41, p < 0.01), content of terrigenous elements (major elements with the origin in watershed rocks) is positively correlated (up to r = 0.44, p < 0.01) with annual precipitation. A high statistically significant negative relationship is observed between the concentrations of terrigenous elements and tree-ring width of local pine chronology (up to r = -0.56, p < 0.01). Taken together, these data point to a common composite climatic signal in the two independent records (lake sediments and tree rings) and confirm that the laminae represent annual layers (i.e., varves). These findings open opportunities for high-resolution multiproxy climate reconstructions 300–350 years long using the longer sediment core and tree-ring records

Biological Earth observation with animal sensors

Space-based tracking technology using low-cost miniature tags is now delivering data on fine-scale animal movement at near-global scale. Linked with remotely sensed environmental data, this offers a biological lens on habitat integrity and connectivity for conservation and human health; a global network of animal sentinels of environmen-tal change

Glacial history of the Kuznetsky Alatay Mountains

Field investigations showed that the leeward slopes across the Kuznetsky Alatay Mountains (also the windward slopes in the Tigertysh ridge) are intensively eroded by glaciers and represent the classical type of “alpine-type landscape”. Accumulative glacial landforms are developed in all types of glacial valleys. Study of five valleys (the Karatas, the Lower and the Upper Tayzhasu, Perekhodnya, the right source of the Small Kazyr Rivers) showed that four stadial moraine complexes can be identified. These moraines are very different by their morphology. They indicate the change of glaciation from large ancient valley glaciers to modern small cirque and slope glaciers. In this article, the first data are assessed about evolution of glaciers and climate in the Kuznetsky Alatay Mountains from the Last Glacial Maximum of Late Pleistocene (between 26,500 and 19,000–20,000 years BP) to nowadays on the basis of studies of glacial landforms, sedimentology, and biostratigraphy. In the Glacier inventory complied in 1970s-early 1980s, 91 glaciers were recorded in the Kuznetsky Alatay; however, some were erroneously identified as glaciers. The review of the current changes of modern glaciation of the Kuznetsky Alatay is made on the basis of repeated photographs and direct field measurements of 30 glaciers. 18 out of the 30 studied glaciers melted away completely, their area decreased from 1.4 to 0.5–0.3 km2. Not all glaciers strongly degraded. Large cirque glaciers have not changed significantly. Over the past 110 years, the area of perennial snowfields in the Kuznetsky Alatay Mountains had reduced by 90 %. Over the century, the timberline has risen by about 50 m and is currently located at 1220–1200 m a.s.l

Glacial history of the Kuznetsky Alatay Mountains

Field investigations showed that the leeward slopes across the Kuznetsky Alatay Mountains (also the windward slopes in the Tigertysh ridge) are intensively eroded by glaciers and represent the classical type of “alpine-type landscape”. Accumulative glacial landforms are developed in all types of glacial valleys. Study of five valleys (the Karatas, the Lower and the Upper Tayzhasu, Perekhodnya, the right source of the Small Kazyr Rivers) showed that four stadial moraine complexes can be identified. These moraines are very different by their morphology. They indicate the change of glaciation from large ancient valley glaciers to modern small cirque and slope glaciers. In this article, the first data are assessed about evolution of glaciers and climate in the Kuznetsky Alatay Mountains from the Last Glacial Maximum of Late Pleistocene (between 26,500 and 19,000–20,000 years BP) to nowadays on the basis of studies of glacial landforms, sedimentology, and biostratigraphy. In the Glacier inventory complied in 1970s-early 1980s, 91 glaciers were recorded in the Kuznetsky Alatay; however, some were erroneously identified as glaciers. The review of the current changes of modern glaciation of the Kuznetsky Alatay is made on the basis of repeated photographs and direct field measurements of 30 glaciers. 18 out of the 30 studied glaciers melted away completely, their area decreased from 1.4 to 0.5–0.3 km2. Not all glaciers strongly degraded. Large cirque glaciers have not changed significantly. Over the past 110 years, the area of perennial snowfields in the Kuznetsky Alatay Mountains had reduced by 90 %. Over the century, the timberline has risen by about 50 m and is currently located at 1220–1200 m a.s.l

Glacial geomorphology of the Notsarula and Chanchakhi river valleys, Georgian Caucasus

Detailed glacial geomorphological maps are valuable for identifying target sites for palaeoglaciological reconstructions and thus for palaeoclimate inferences. In this study, we present the first detailed glacial geomorphological mapping of the landform assemblages produced by the former glaciers in the Notsarula (42°45′44″N 43°38′29″E) and Chanchakhi (42°42′5″N 43°40′42″E) river valleys, Georgian Caucasus. Our goal is to create a high-resolution (1:33,000 scale) glacial geomorphological map of this area (237 km2) and provide a detailed and accurate distribution of glacier-related features (see Main Map). Several field investigations between 2010 and 2022 along with detailed remote sensing surveys have been conducted for this glacial geomorphological mapping. The mapped landforms indicate multiple readvance or stillstands of valley glaciers across the study area. The largest and complex glacier body likely existed in the Bubistskali River gorge (42°43′16″N 43°43′32″E). Well-preserved moraine landforms in this valley suggest at least five large and several relatively small glacier readvances or stillstands occurred during the Late Quaternary. The simple-valley-type (without branches) glaciers were also probably present in other tributary valleys of the Chanchakhi River basin at that time. This map can be used for further geomorphological investigation as well as to support future geochronological work in the Greater Caucasus.</p

Reconstructed summer temperatures over the last 400 years based on Larch ring widths: Sakhalin Island, Russian Far East

A new ring-width record from the eastern flanks of the Eastern Sakhalin Range, Sakhalin Island, Russian Federation is significantly correlated with summer temperatures and allows for the reconstruction of May–July average temperatures for the past 400 years. The reconstruction explains 37 % of the variance in May–July temperatures and shows a strong cooling between 1680 and 1710 CE coincident with the Maunder solar minimum and in agreement with other independent tree-ring reconstructions and glacier histories from sites along the margin of the Sea of Okhotsk. While recent decades are among the warmest in the record they are rivaled by periods centered on 1650 and 1850 CE. Warming in the observational record and the reconstruction is consistent with the influence of the declining strength of the Siberian High and loss of sea ice over the same interval. Decadal (17–25 year) variability persists throughout the reconstruction. At interannual timescales the Sakhalin reconstruction is most strongly correlated with local and central North Pacific sea surface temperatures over the past 120 years, whereas at decadal timescales there is an additional association with Asian land surface temperatures

Reconstructed summer temperatures over the last 400 years based on Larch ring widths: Sakhalin Island, Russian Far East

A new ring-width record from the eastern flanks of the Eastern Sakhalin Range, Sakhalin Island, Russian Federation is significantly correlated with summer temperatures and allows for the reconstruction of May–July average temperatures for the past 400 years. The reconstruction explains 37 % of the variance in May–July temperatures and shows a strong cooling between 1680 and 1710 CE coincident with the Maunder solar minimum and in agreement with other independent tree-ring reconstructions and glacier histories from sites along the margin of the Sea of Okhotsk. While recent decades are among the warmest in the record they are rivaled by periods centered on 1650 and 1850 CE. Warming in the observational record and the reconstruction is consistent with the influence of the declining strength of the Siberian High and loss of sea ice over the same interval. Decadal (17–25 year) variability persists throughout the reconstruction. At interannual timescales the Sakhalin reconstruction is most strongly correlated with local and central North Pacific sea surface temperatures over the past 120 years, whereas at decadal timescales there is an additional association with Asian land surface temperatures

Dynamics of seasonal patterns in geochemical, isotopic, and meteorological records of the elbrus region derived from functional data clustering

A nonparametric clustering method, the Bagging Voronoi K-Medoid Alignment algorithm, which simultaneously clusters and aligns spatially/temporally dependent  curves,  is applied to study various data series from the Elbrus  region (Central Caucasus). We used the algorithm to cluster annual curves obtained by smoothing of the following synchronous data series: titanium concentrations in varved (annually laminated) bottom sediments of proglacial  Lake Donguz-Orun;  an oxygen-18 isotope record in an ice core from Mt. Elbrus; temperature and precipitation observations with a monthly resolution from Teberda and Terskol meteorological stations. The data of different types were clustered independently. Due to restrictions concerned with the availability of meteorological data, we have fulfilled the clustering procedure separately for two periods: 1926–2010 and 1951–2010. The study is aimed to determine whether the instrumental period could be reasonably divided (clustered)  into several sub-periods using different climate and proxy time series; to examine the interpretability of the resulting borders of the clusters (resulting time periods); to study typical patterns of intra-annual variations of the data series. The results of clustering suggest that the precipitation and to a lesser degree titanium decadal-scale data may be reasonably grouped, while the temperature and oxygen-18 series are too short to form meaningful clusters; the intercluster boundaries show a notable degree of coherence between temperature and oxygen-18 data, and less between titanium and oxygen-18 as well as for precipitation series; the annual curves for titanium and partially precipitation data reveal much more pronounced intercluster  variability than the annual patterns of temperature and oxygen-18 data