Antarctic ice-shelf meltwater outflows in satellite radar imagery: ground-truthing and basal channel observations DOI Creative Commons
Jakob Stanley Hamann, Thomas Arney, James D. Kirkham

et al.

Journal of Glaciology, Journal Year: 2024, Volume and Issue: unknown, P. 1 - 13

Published: Oct. 14, 2024

Abstract Ice shelves regulate the flow of Antarctic ice sheet toward ocean and its contribution to sea-level rise. Accurately monitoring basal surface melting is therefore essential for predicting sheet's response climatic warming. In this study, we utilize Sentinel-1A synthetic aperture radar satellite imagery combined with shipboard measurements water temperature salinity investigate presence surficial meltwater plumes along coastline. Our approach reveals a strong correlation between areas pronounced low backscatter extending from significant decreases in salinity, suggesting meltwater-enriched waters. We propose that signature outflows caused by stable stratification upper column, driven density contrasts buoyant, low-salinity current shear reduce Bragg scattering waves. The resulting smooth surfaces were observed adjacent expression deep channels, documented helicopter survey part Bellingshausen Sea edge. present high-temporal resolution as tool identifying release beneath shelves, capable all-weather, day-and-night imaging.

Language: Английский

2023: Weather and Climate Extremes Hitting the Globe with Emerging Features DOI Creative Commons
Wenxia Zhang, Robin Clark, Tianjun Zhou

et al.

Advances in Atmospheric Sciences, Journal Year: 2024, Volume and Issue: 41(6), P. 1001 - 1016

Published: April 17, 2024

Globally, 2023 was the warmest observed year on record since at least 1850 and, according to proxy evidence, possibly of past 100 000 years. As in recent years, warmth has again been accompanied with yet more extreme weather and climate events throughout world. Here, we provide an overview those 2023, details key background causes help build upon our understanding roles internal variability anthropogenic change. We also highlight emerging features associated some these events. Hot extremes are occurring earlier year, increasingly simultaneously differing parts world (e.g., concurrent hot Northern Hemisphere July 2023). Intense cyclones exacerbating precipitation North China flooding Libya September). Droughts regions California Horn Africa) have transitioned into flood conditions. Climate show increasing interactions ecosystems via wildfires Hawaii August Canada from spring autumn 2023) sandstorms Mongolia April Finally, consider challenges research that characteristics present for strategy practice adaptation.

Language: Английский

Citations

22
Evolution of Antarctic Sea Ice Ahead of the Record Low Annual Maximum Extent in September 2023 DOI Creative Commons
Babula Jena,

S. Kshitija,

C. C. Bajish

et al.

Geophysical Research Letters, Journal Year: 2024, Volume and Issue: 51(7)

Published: March 27, 2024

Abstract The 2023 Antarctic sea ice extent (SIE) maximum on 7 September was the lowest annual in satellite era (16.98 × 10 6 km 2 ), with largest contributions to anomaly coming from Ross (37.7%, −0.57 ) and Weddell (32.9%, −0.49 Seas. SIE low due anomalously warm (>0.3°C) upper‐ocean temperatures combined strong northerly winds impeding advance during fall winter. Northerly of >12 ms −1 Sea occurred because negative pressure anomalies over Peninsula, while those were associated extreme blocking episodes off Ice Shelf. experienced an unprecedented decrease −1.08 3 d 1 June till maximum. passage quasi‐stationary explosive polar cyclones contributed periods southward ice‐edge shift both sectors.

Language: Английский

Citations

12
CMIP6 Models Rarely Simulate Antarctic Winter Sea‐Ice Anomalies as Large as Observed in 2023 DOI Creative Commons
Rachel Diamond, Louise Sime, Caroline Holmes

et al.

Geophysical Research Letters, Journal Year: 2024, Volume and Issue: 51(10)

Published: May 20, 2024

Abstract In 2023, Antarctic sea‐ice extent (SIE) reached record lows, with winter SIE falling to 2.5Mkm 2 below the satellite era average. With this multi‐model study, we investigate occurrence of anomalies magnitude in latest‐generation global climate models. When these occur, takes decades recover: indicates that may transition a new, lower, state over next few decades. Under internal variability alone, models are extremely unlikely simulate anomalies, return period >1000 years for most The only <1000 have likely unrealistically large interannual variability. Based on extreme value theory, is reduced from 2650 under 580 strong change forcing scenario.

Language: Английский

Citations

9
Antarctica in 2025: Drivers of deep uncertainty in projected ice loss DOI
H. A. Fricker, Benjamin K. Galton‐Fenzi, C. C. Walker

et al.

Science, Journal Year: 2025, Volume and Issue: 387(6734), P. 601 - 609

Published: Feb. 6, 2025

Antarctica is a vital component of Earth’s climate system, influencing global sea level, ocean circulation, and planetary albedo. Major knowledge gaps in critical processes—spanning the atmosphere, ocean, ice sheets, underlying beds, shelves, ice—create uncertainties future projections, hindering adaptation risk assessments intervention strategies. Antarctica’s sheet could contribute 28 centimeters to level by 2100, potentially more if we surpass warming thresholds that trigger instabilities rapid retreat. We review recent advances understanding changing stability margins identify key processes require further research. Progress requires high-resolution satellite data, targeted field campaigns, improved modeling, refined theory. Increased investment interdisciplinary collaboration are essential uncovering hidden reducing projections.

Language: Английский

Citations

1
Will 2024 be the first year that global temperature exceeds 1.5°C? DOI Creative Commons
Nick Dunstone, Doug Smith,

Chris Atkinson

et al.

Atmospheric Science Letters, Journal Year: 2024, Volume and Issue: 25(9)

Published: June 13, 2024

Abstract Global mean near surface temperature change is the key metric by which our warming climate monitored and for international policy set. At end of each year Met Office issues a global forecast coming year. Following on from new record in 2023, we predict that 2024 will likely (76% chance) be with 1‐in‐3 chance exceeding 1.5°C above pre‐industrial. Whilst one‐year temporary exceedance would not constitute breach Paris Agreement target, highlights how close are now to this. Our primarily driven strong trend +0.2°C/decade (1981–2023) secondly lagged effect tropical Pacific El Niño event. We highlight 2023 itself was significantly warmer than DePreSys3 forecast, much this additional observed southern hemisphere, cause requires further understanding.

Language: Английский

Citations

7
Earth's Sea Ice Radiative Effect From 1980 to 2023 DOI Creative Commons
Alisher Duspayev, M. Flanner, Aku Riihelä

et al.

Geophysical Research Letters, Journal Year: 2024, Volume and Issue: 51(14)

Published: July 17, 2024

Abstract Sea ice cools Earth by reducing its absorbed solar energy. We combine radiative transfer modeling with satellite‐derived surface albedo, sea ice, and cloud distributions to quantify the top‐of‐atmosphere effect (SIRE). Averaged over 1980–2023, Arctic Antarctic SIREs range from −0.64 −0.86 W m −2 −0.85 −0.98 , respectively, different data sets assumptions of climatological versus annually‐varying clouds. SIRE trends, however, are relatively insensitive these assumptions. has weakened quasi‐linearly at a rate 0.04–0.05 decade −1 implying 21%–27% reduction in reflective power since 1980. exhibited regime change 2016, resulting 2016–2023 global being 0.08–0.12 0.22–0.27 weaker, relative 1980–1988. Global therefore lost 13%–15% planetary cooling early/mid 1980s, implied albedo feedback is 0.24–0.38 K .

Language: Английский

Citations

5
The atmospheric ‘cold blob’ over Fennoscandia from October 2023 to January 2024 DOI Creative Commons
Mika Rantanen, Otto Hyvärinen, Andrea Vajda

et al.

Weather, Journal Year: 2024, Volume and Issue: unknown

Published: May 6, 2024

Abstract Between October 2023 and January 2024, a remarkably persistent cold air anomaly prevailed over Fennoscandia on an otherwise record‐warm planet. This article describes the temperature anomalies, atmospheric circulation seasonal predictions associated with blob. The 4‐month period from to was third coldest in during ongoing century. blob anomalous circulation; for example, jet stream wind speeds were exceptionally high south of Fennoscandia. Furthermore, forecasts failed capture blob, which may be related difficulties simulating El Niño teleconnections by long‐range forecasting systems.

Language: Английский

Citations

4
Understanding the drivers and predictability of record low Antarctic sea ice in austral winter 2023 DOI Creative Commons
Zachary Espinosa, Edward Blanchard‐Wrigglesworth, Cecilia M. Bitz

et al.

Communications Earth & Environment, Journal Year: 2024, Volume and Issue: 5(1)

Published: Nov. 20, 2024

Since the start of satellite record in 1978, three lowest summertime minima Antarctic sea ice area all occurred within last seven years and culminated low austral winter 2023. During this period was over 2 million km2 below climatology, a 5 sigma anomaly 0.9 previous largest seasonal anomaly. Here we show that fully-coupled Earth System Model nudged to observed winds reproduces low, 2023 transition from La Niña El Niño had minimal impact. Using an ensemble, demonstrate ~ 70% predictable six months advance driven by warm Southern Ocean conditions developed prior 2023, with remaining 30% attributable atmospheric circulation. An ensemble forecast correctly predicted near would persist 2024, due persistent conditions. area's surface temperatures, while circulation, impact, according results system model

Language: Английский

Citations

4
Nutritional consistency of macroalgae across a sea ice cover gradient along the Western Antarctic Peninsula DOI Creative Commons
Hannah E. Oswalt, Margaret O. Amsler, Charles D. Amsler

et al.

Journal of Phycology, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 12, 2025

Abstract Sea ice can profoundly influence photosynthetic organisms by altering subsurface irradiance, but it is susceptible to changes in the climate. The patterns and timing of sea cover vary on a monthly annual timescale small sub‐regions Western Antarctic Peninsula (WAP). During latter part 20th century, coverage significantly decreased WAP, trend that aligns with warming this area. Macroalgal biochemical components are impacted light availability, often showing close relationship between photosynthesis compositions. We used satellite imagery duration extent as well water turbidity during ice‐free periods identify 14 study sites differed dramatically were similar terms along central WAP 68° S 64° S. common macroalgal species Desmarestia menziesii , Himantothallus grandifolius Sarcopeltis antarctica Iridaea sp. collected scuba divers 5 m 35 depth at each site where they occurred, for later analyses. Overall percentages major carbon nitrogen C:N determined correlated four different indices. Surprisingly, most chemical not cover. few significant correlations varied components. This indicates although have implications abundance, per‐biomass basis, does impact nutritional contributions macroalgae food webs.

Language: Английский

Citations

0
Integrated retrieval of sea-ice salinity, density, and thickness using polarimetric GNSS-R DOI
Joan Francesc Muñoz-Martín, Nereida Rodriguez-Alvarez, Xavier Bosch-Lluis

et al.

Remote Sensing of Environment, Journal Year: 2025, Volume and Issue: 318, P. 114617 - 114617

Published: Jan. 26, 2025

Language: Английский

Citations

0