Dynamics of Permafrost Coasts of Baydaratskaya Bay (Kara Sea) Based on Multi-Temporal Remote Sensing Data

Abstract

Arctic coasts that are composed of frozen deposits are extremely sensitive to climate change and human impact. They retreat with average rates of 1–2 m per year, depending on climatic and permafrost conditions. In recent decades, retreat rates have shown a tendency to increase. In this paper, we studied the coastal dynamics of two key sites (Ural and Yamal coasts) of Baydaratskaya Bay, Kara Sea, where a gas pipeline had been constructed. Based on multi-temporal aerial and satellite imagery, we identified coastal erosion rates at several time lapses, in natural conditions and under human impact, and discussed their temporal variability. In addition to planimetric (m/yr), we calculated volumetric (m3/m/yr) retreat rates of erosional coasts using ArcticDEM. We also estimated the influence of geomorphology, lithology, and permafrost structure of the coasts on spatial variations of their dynamics. Erosional coasts of the Ural key site retreat with higher mean rates (1.2 m/yr and 8.7 m3/m/yr) as compared to the Yamal key site (0.3 m/yr and 3.7 m3/m/yr) due to their exposure to higher open sea waves, more complex lithology, higher ice content and lower coastal bluffs. Since the 1960s, coastal retreat rates have been growing on both coasts of Baydaratskaya Bay; we relate this effect with Arctic climate warming. From the 1960s to 2005, such growth was moderate, while in 2005–2016 it became rapid, which may be explained by the enhanced wave and thermal action or by the onset of industrial development. The adjacent coastal segments, originally accumulative, remained relatively stable from the 1960s to 2005. After 2005, a considerable part of them began to retreat as a result of changing weather conditions and/or increasing human impact.

Cliff retreat of permafrost coast in south‐west Baydaratskaya Bay, Kara Sea, during 2005–2016

“…At the Marresale site (Figure ), the cliff retreated at mean annual rates of 0.5–2.5 m/yr between 1978 and 2010, with a maximum rate of 3.3 m/yr in 1989 and 1990 . By contrast, the south‐east coast of Baydaratskaya Bay in the south‐west Yamal Peninsula was eroding at mean annual rates of 0.1–0.6 m/yr, which were lower than those reported in the central–west and north‐west Yamal Peninsula coasts. Most coastal sites in the western Baydaratskaya Bay and the western Yugorsky Peninsula were retreating at mean annual rates of 0.4–2.0 m/yr, although several of the sites were stable during 2005 and 2012 .…”

“…Numerous studies have looked at the coastal dynamics in the Kara Sea coasts since the 1960s based on field measurements and analyses of satellite and aerial images (e.g., ). They revealed that mean annual rates of coastal retreat ranged between 0.2 m/yr and 2.0 m/yr for most of the Kara Sea coasts in the last 50 years while several coastal sites were stable or accreting.…”

“…The Gulf of Ob coast was eroding at moderate rates for the Kara Sea coasts, with mean erosion rates of 0.33–0.7 m/yr . In contrast, the Western Yamal Peninsula coast showed variable retreat rates, with mean annual rates of 0.1 m/yr and 2.5 m/yr . A coastline along the Kharasaveyskoye gas field in the western Yamal Peninsula, located ~90 km north of the Bovanenkovskoye gas field (see Figure for location), retreated by 28.5–39.1 m between 1976 and 2007 (ref…”

“…Thus, studies of the Kara Sea coast hold promise for further understanding the dynamic processes at the land–ocean interface over the entire Arctic – repositioning and reshaping of the Arctic coastline. Most recently, Novikova et al . reported on long‐term coastal retreat along the Baydaratskaya Bay coast in the Kara Sea based on satellite and aerial imagery, and revealed that mean annual rates of coastal retreat had increased from the period 1964–2005 to 2005–2016 probably due to climate warming and human activity.…”

Rapid retreat of permafrost coastline observed with aerial drone photogrammetry

“…200 mm a −1 (Burn, 2012). The average coastal erosion rate for the whole of Qikiqtaruk -Herschel Island was 0.45 m a −1 between 1970 and 2000 (Lantuit and Pollard, 2005;Obu et al, 2015) and 0.68 m a −1 between 2000 and 2011 (Obu et al, 2016).…”