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The Tröllaskagi peninsula is located in northern Iceland, between meridian 19°30'W and 18°10'W, jutting out into the North Atlantic to latitude 66°12'N. The aim of this research is to study recent glacier changes in relation to climatic evolution of the Gljúfurárjökull and Tungnahryggsjökull debris-free valley glaciers in Tröllaskagi. Glacier extent mapping and spatial analysis operations were performed with ArcGIS (ESRI), using analysis of aerial photographs from 1946, 1985, 1994 and 2000, and a 2005 SPOT satellite image. The results show that these glaciers lost a quarter of their surface area between the 'Little Ice Age' and 2005. In this paper, the term 'Little Ice Age' follows Grove (2001) as the most recent period when glaciers extended globally between the medieval period and the early 20th century. The abrupt climatic transition of the early 20th century and the 25-year warm period 1925-1950 triggered the main retreat and volume loss of these glaciers since the end of the 'Little Ice Age'. Meanwhile, cooling during the 1960s, 1970s and 1980s altered the trend, with advances of the glacier snouts. Between the 'Little Ice Age' and the present day, the mean annual air temperature and mean ablation season air temperature increased by 1.9°C and 1.5°C, respectively, leading to a 40-50 m rise in the equilibrium line altitude (ELA) of the glaciers during this period. The response of these glaciers depends not only on the mean ablation season air temperature evolution but also on other factors such as winter precipitation. The models applied show a precipitation increase of up to more than 700 mm since the 'Little Ice Age'. [ABSTRACT FROM AUTHOR]

A set of paleoflood slack water deposit (SWD) beds was identified within slope clasts at the Jinpingcun (JPC) site in the Jingyuan–Jingtai reaches of the upper Yellow River gorges based on sedimentary criteria and analytical results. Paleoflood hydrology methods were applied to reconstruct paleoflood events in the Jingyuan–Jingtai reaches. The paleoflood peak stages were calculated based on the highest end-point elevations of the SWDs. The HEC-RAS model and optically stimulated luminescence dating enabled robust paleo-discharge estimates to be calculated between 12,750 and 16,310 m3/s for paleoflood events that occurred during 3200–3000 a BP. The peak discharges, including gauged and historical flood data at the Lanzhou gauge station and the reconstructed paleoflood peak discharges at the JPC site, were input for flood frequency analysis. These paleo-hydrological approaches can also be applied to other regions in the Yellow River gorges. Furthermore, the ages of the paleoflood events correspond well with the known climatic events at 3100 a BP during Holocene climatic variability. These findings are significant for flood risk estimation, in the assessment of water sources in dryland environments, and in understanding the interactions between hydrological systems and climatic change in arid and semi-arid regions of the upper Yellow River in China. [ABSTRACT FROM AUTHOR]

Most rich-fen bryophyte species are currently declining and red listed in many European countries. Little is known about their past and current occurrence. We investigated past and recent bryophyte assemblages in mires in the land uplift coast of Finland. The study areas included primary succession areas where mire development started c. 6000 BP. In total, seven mires were studied in two successional transects along the land uplift coast. The past occurrences of rich-fen and other bryophytes were studied in 45 mire stratigraphic peat profiles, and recent occurrences were collected from 158 vegetation plots of 10 m × 10 m. Bryophyte subfossils indicated that the central parts of the basins developed first to wet rich fens with groundwater influence, which developed towards intermediate fens or poorer mire types. Most mire bryophytes occurred in about the same proportion in peat profiles as in recent vegetation. Five rich-fen species (Hamatocaulis lapponicus, H. vernicosus, Meesia longiseta, M. triquetra and Pseudocalliergon trifarium) were clearly more common in peat profiles than in the present mire vegetation, where these species were very rare and appeared only in small patches without sporophytes. These rich-fen species have had markedly wider distributions in the past, probably linked to climate fluctuations, whereas current occurrences are becoming scarce because of multiple anthropogenic factors such mire drainage and climate change. [ABSTRACT FROM AUTHOR]

Coastal marine Holocene deposits of the Apulia region, considered as indicators of palaeoclimatic conditions, were studied. Our data show that (1) up to c. 5500 cal. yr BP, a phase of accumulation of flint pebbles from the Gargano headland occurred at the Riviera sud di Manfredonia (Adriatic coast); their transport from the Gargano headland (north of the study site) is incompatible with the current northward littoral drift and is best explained by a prevalence and dominance of NE and E winds and (2) after c. 4500 cal. yr BP, there was a rapid accumulation of sediments at the Marina di Ugento (Ionian coast), which is best explained by a prevalence and dominance of S, SW and SE winds. The two different wind regimes identified can be explained by a change in the mean pressure configuration in the central Mediterranean. The first phase (until c. 5500 cal. yr BP) consisted of more frequent cyclogenesis to the east-southeast of the Italian Peninsula, followed by a second phase (from c. 4500 cal. yr BP) of more frequent cyclogenesis to the west-northwest. The period between 5500 and 4500 cal. yr BP represents a transitional phase between the two different regimes. In other words, there was a ‘retreat’ of the central Mediterranean cyclogenesis towards the west-northwest. This pattern is contemporaneous with the termination of the African Humid period. We interpret both the ‘retreat’ of the Mediterranean cyclogenesis and the termination of the African Humid period as the expression of an expansion of the tropical dry Saharan belt. [ABSTRACT FROM AUTHOR]

The Northeastern China involves complex interactions between the East Asian summer monsoon (EASM) circulation and the polar climate system, and plays a significant role as the bridge communicating low- and high-latitude climatic processes. High-resolution multi-proxy analysis of a robust accelerator mass spectrometry (AMS) 14C dated lacustrine sediment core recovered from Jingpo Lake in Northeastern China provides a detailed history of EASM variability and vegetation changes since ~5100 cal. yr BP. The period from ~5100 to 3600 cal. yr BP was characterized by the highest pollen percentages of Quercus, Ulmus, Juglans and Corylopsis; low Md (median grain size diameter); and high δ13Corg values, reflecting a relatively warm and humid period. The period between ~3600 and 2100 cal. yr BP is characterized by high Md and low δ13Corg values, and a rapid increase in pollen percentages of herbs, indicating cool and dry climatic conditions. From ~2100 to 150 cal. yr BP, a gradual increase in δ13Corg values and low Md values, and a rapid increase in Carpinus, Juglans and Corylopsis pollen percentages was observed, indicating climate change towards warmer and wetter conditions. After ~150 cal. yr BP, the highest values of total organic carbon mass accumulation rate (TOC-MAR), total nitrogen mass accumulation rate (TN-MAR) and magnetic susceptibility suggesting that the Jingpo Lake region has been severely affected by human activities. The EASM variability in Northeastern China during the mid- to late Holocene shows trends similar to EASM records in China. Furthermore, our findings indicate that the variability of the EASM during the mid- to late Holocene on the multi-decadal to centennial scale was forced by changes in both solar output and oceanic–atmospheric circulation interaction. [ABSTRACT FROM PUBLISHER]