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 Weddell Sea


A huge iceberg becomes a deadly trap for penguins

Popular Science

An iceberg sealed the penguin colony's entrance, triggering a 70% survival drop. A group of Emperor penguin chicks is walking on the fast ice at the Emperor penguin colony at Snow Hill Island in the Weddell Sea in Antarctica. Breakthroughs, discoveries, and DIY tips sent six days a week. A massive iceberg has triggered a catastrophic die-off of Emperor Penguin chicks in Antarctica, blocking thousands of parents from reaching their young. The event claimed the lives of approximately 14,000 chicks at the Coulman Island colony in the Ross Sea, the region's largest breeding ground.


The quest to find Shackleton's ship uncovered an Antarctic mystery

Popular Science

Environment Animals Wildlife Fish The quest to find Shackleton's ship uncovered an Antarctic mystery Beneath the ice, an underwater robot discovered something far stranger than the'Endurance' shipwreck. Breakthroughs, discoveries, and DIY tips sent every weekday. The Antarctic Ocean's brutal conditions ultimately doomed Ernest Shackleton's famed 1915 expedition aboard the . Although the icy environment has quickly turned fatal for many unfortunate explorers, it's not an entirely inhospitable place . While attempting to locate Shackleton's sunken ship in 2019, researchers unexpectedly documented a strange sight-a sprawling, geometric complex of over 1,000 icefish nests .


Ernest Shackleton knew 'Endurance' had shortcomings, new study says

Popular Science

Ernest Shackleton knew'Endurance' had shortcomings, new study says Issues with the ship's hull, deck beams, and more show the ship was no match for Antarctic sea ice. The'Endurance' leaning to one side, during the Imperial Trans-Antarctic Expedition, 1914-17, led by Sir Ernest Shackleton. Breakthroughs, discoveries, and DIY tips sent every weekday. For almost 110 years, the has rested at the bottom of the icy waters of the Antarctic's Weddell Sea . Long held as the poster ship for Antarctic exploration, Sir Ernest Shackleton's ill-fated ship was no match for the crushing sea ice that sank it in November 1915 .


The Shipwreck Detective

The New Yorker

The wreck was like a bug on the wall, a jumbly shape splayed on the abyssal plain. It was noticed by a team of autonomous-underwater-vehicle operators on board a subsea exploration vessel, working at an undisclosed location in the Atlantic Ocean, about a thousand miles from the nearest shore. The analysts belonged to a small private company that specializes in deep-sea search operations; I have been asked not to name it. They were looking for something else. In the past decade, the company has helped to transform the exploration of the seabed by deploying fleets of A.U.V.s--underwater drones--which cruise in formation, mapping large areas of the ocean floor with high-definition imagery.


See Ernest Shackleton's ship like NEVER before: Incredible 3D scans reveal exactly what Endurance would have looked like before it sank in 1915

Daily Mail - Science & tech

Its discovery 3,000 metres beneath the Antarctic ice in 2022 was nothing short of miraculous. But now, stunning images make it possible to see Ernest Shackleton's ship, Endurance, like never before. Released as part of a new documentary called Endurance, this model shows exactly what the ship would have looked like before it was lost to the ice in 1915. From plates used for the daily meals to the flare gun fired in tribute to the sinking ship, the scan reveals the minute details of life aboard Endurance. Nico Vincent, of Deep Ocean Search who developed the technology for the scan, told the BBC: 'It's absolutely fabulous.


Robustness of AI-based weather forecasts in a changing climate

arXiv.org Artificial Intelligence

Data-driven machine learning models for weather forecasting have made transformational progress in the last 1-2 years, with state-of-the-art ones now outperforming the best physics-based models for a wide range of skill scores. Given the strong links between weather and climate modelling, this raises the question whether machine learning models could also revolutionize climate science, for example by informing mitigation and adaptation to climate change or to generate larger ensembles for more robust uncertainty estimates. Here, we show that current state-of-the-art machine learning models trained for weather forecasting in present-day climate produce skillful forecasts across different climate states corresponding to pre-industrial, present-day, and future 2.9K warmer climates. This indicates that the dynamics shaping the weather on short timescales may not differ fundamentally in a changing climate. It also demonstrates out-of-distribution generalization capabilities of the machine learning models that are a critical prerequisite for climate applications. Nonetheless, two of the models show a global-mean cold bias in the forecasts for the future warmer climate state, i.e. they drift towards the colder present-day climate they have been trained for. A similar result is obtained for the pre-industrial case where two out of three models show a warming. We discuss possible remedies for these biases and analyze their spatial distribution, revealing complex warming and cooling patterns that are partly related to missing ocean-sea ice and land surface information in the training data. Despite these current limitations, our results suggest that data-driven machine learning models will provide powerful tools for climate science and transform established approaches by complementing conventional physics-based models.


The impact of internal variability on benchmarking deep learning climate emulators

arXiv.org Artificial Intelligence

Full-complexity Earth system models (ESMs) are computationally very expensive, limiting their use in exploring the climate outcomes of multiple emission pathways. More efficient emulators that approximate ESMs can directly map emissions onto climate outcomes, and benchmarks are being used to evaluate their accuracy on standardized tasks and datasets. We investigate a popular benchmark in data-driven climate emulation, ClimateBench, on which deep learning-based emulators are currently achieving the best performance. We implement a linear regression-based emulator, akin to pattern scaling, and find that it outperforms the incumbent 100M-parameter deep learning foundation model, ClimaX, on 3 out of 4 regionally-resolved surface-level climate variables. While emulating surface temperature is expected to be predominantly linear, this result is surprising for emulating precipitation. We identify that this outcome is a result of high levels of internal variability in the benchmark targets. To address internal variability, we update the benchmark targets with ensemble averages from the MPI-ESM1.2-LR model that contain 50 instead of 3 climate simulations per emission pathway. Using the new targets, we show that linear pattern scaling continues to be more accurate on temperature, but can be outperformed by a deep learning-based model for emulating precipitation. We publish our code, data, and an interactive tutorial at github.com/blutjens/climate-emulator.


Stochastic Guidance of Buoyancy Controlled Vehicles under Ice Shelves using Ocean Currents

arXiv.org Artificial Intelligence

We propose a novel technique for guidance of buoyancy-controlled vehicles in uncertain under-ice ocean flows. In-situ melt rate measurements collected at the grounding zone of Antarctic ice shelves, where the ice shelf meets the underlying bedrock, are essential to constrain models of future sea level rise. Buoyancy-controlled vehicles, which control their vertical position in the water column through internal actuation but have no means of horizontal propulsion, offer an affordable and reliable platform for such in-situ data collection. However, reaching the grounding zone requires vehicles to traverse tens of kilometers under the ice shelf, with approximate position knowledge and no means of communication, in highly variable and uncertain ocean currents. To address this challenge, we propose a partially observable MDP approach that exploits model-based knowledge of the under-ice currents and, critically, of their uncertainty, to synthesize effective guidance policies. The approach uses approximate dynamic programming to model uncertainty in the currents, and QMDP to address localization uncertainty. Numerical experiments show that the policy can deliver up to 88.8% of underwater vehicles to the grounding zone -- a 33% improvement compared to state-of-the-art guidance techniques, and a 262% improvement over uncontrolled drifters. Collectively, these results show that model-based under-ice guidance is a highly promising technique for exploration of under-ice cavities, and has the potential to enable cost-effective and scalable access to these challenging and rarely observed environments.


Negative Label Guided OOD Detection with Pretrained Vision-Language Models

arXiv.org Artificial Intelligence

Out-of-distribution (OOD) detection aims at identifying samples from unknown classes, playing a crucial role in trustworthy models against errors on unexpected inputs. Extensive research has been dedicated to exploring OOD detection in the vision modality. Vision-language models (VLMs) can leverage both textual and visual information for various multi-modal applications, whereas few OOD detection methods take into account information from the text modality. In this paper, we propose a novel post hoc OOD detection method, called NegLabel, which takes a vast number of negative labels from extensive corpus databases. We design a novel scheme for the OOD score collaborated with negative labels. Theoretical analysis helps to understand the mechanism of negative labels. Extensive experiments demonstrate that our method NegLabel achieves state-ofthe-art performance on various OOD detection benchmarks and generalizes well on multiple VLM architectures. Furthermore, our method NegLabel exhibits remarkable robustness against diverse domain shifts. In open-world scenarios, deploying machine learning models faces a critical challenge: how to handle data from unknown classes, commonly referred to as out-of-distribution (OOD) data (Hendrycks & Gimpel, 2017). The presence of OOD data can lead to models exhibiting overconfidence, potentially resulting in severe errors or security risks. This issue is particularly pronounced in critical applications, such as autonomous vehicles and medical diagnosis. Therefore, detecting and rejecting OOD data plays a crucial role in ensuring the reliability and safety of the model. Traditional visual OOD detection methods (Hsu et al., 2020a; Wang et al., 2021b; Huang et al., 2021; Sun et al., 2021; Wang et al., 2021a) typically rely solely on image information, ignoring the rich textual information carried by labels. Vision-language models (VLMs) can leverage multimodal information, which is also beneficial for OOD detection. Some recently proposed methods attempt to design dedicated OOD detectors for VLMs. Specifically, ZOC (Esmaeilpour et al., 2022) defines the new task - zero-shot OOD detection, and uses a trainable captioner to generate candidate OOD labels to match OOD images. However, when dealing with large-scale datasets encompassing a multitude of in-distribution (ID) classes, like ImageNet-1k, the captioner may not generate effective candidate OOD labels, resulting in poor performance. MCM (Ming et al., 2022a) uses the maximum logit of scaled softmax to identify OOD images. However, MCM only employs information from the ID label space and does not effectively exploit the text interpretation capabilities of VLMs.


A Parallel Workflow for Polar Sea-Ice Classification using Auto-labeling of Sentinel-2 Imagery

arXiv.org Artificial Intelligence

The observation of the advancing and retreating pattern of polar sea ice cover stands as a vital indicator of global warming. This research aims to develop a robust, effective, and scalable system for classifying polar sea ice as thick/snow-covered, young/thin, or open water using Sentinel-2 (S2) images. Since the S2 satellite is actively capturing high-resolution imagery over the earth's surface, there are lots of images that need to be classified. One major obstacle is the absence of labeled S2 training data (images) to act as the ground truth. We demonstrate a scalable and accurate method for segmenting and automatically labeling S2 images using carefully determined color thresholds. We employ a parallel workflow using PySpark to scale and achieve 9-fold data loading and 16-fold map-reduce speedup on auto-labeling S2 images based on thin cloud and shadow-filtered color-based segmentation to generate label data. The auto-labeled data generated from this process are then employed to train a U-Net machine learning model, resulting in good classification accuracy. As training the U-Net classification model is computationally heavy and time-consuming, we distribute the U-Net model training to scale it over 8 GPUs using the Horovod framework over a DGX cluster with a 7.21x speedup without affecting the accuracy of the model. Using the Antarctic's Ross Sea region as an example, the U-Net model trained on auto-labeled data achieves a classification accuracy of 98.97% for auto-labeled training datasets when the thin clouds and shadows from the S2 images are filtered out.