Indian Ocean
SeaSplat: Representing Underwater Scenes with 3D Gaussian Splatting and a Physically Grounded Image Formation Model
Yang, Daniel, Leonard, John J., Girdhar, Yogesh
We introduce SeaSplat, a method to enable real-time rendering of underwater scenes leveraging recent advances in 3D radiance fields. Underwater scenes are challenging visual environments, as rendering through a medium such as water introduces both range and color dependent effects on image capture. We constrain 3D Gaussian Splatting (3DGS), a recent advance in radiance fields enabling rapid training and real-time rendering of full 3D scenes, with a physically grounded underwater image formation model. Applying SeaSplat to the real-world scenes from SeaThru-NeRF dataset, a scene collected by an underwater vehicle in the US Virgin Islands, and simulation-degraded real-world scenes, not only do we see increased quantitative performance on rendering novel viewpoints from the scene with the medium present, but are also able to recover the underlying true color of the scene and restore renders to be without the presence of the intervening medium. We show that the underwater image formation helps learn scene structure, with better depth maps, as well as show that our improvements maintain the significant computational improvements afforded by leveraging a 3D Gaussian representation.
Large Language Model Predicts Above Normal All India Summer Monsoon Rainfall in 2024
Sharma, Ujjawal, Biyani, Madhav, Suresh, Akhil Dev, Bhuyan, Debi Prasad, Mishra, Saroj Kanta, Chakraborty, Tanmoy
Reliable prediction of the All India Summer Monsoon Rainfall (AISMR) is pivotal for informed policymaking for the country, impacting the lives of billions of people. However, accurate simulation of AISMR has been a persistent challenge due to the complex interplay of various muti-scale factors and the inherent variability of the monsoon system. This research focuses on adapting and fine-tuning the latest LLM model, PatchTST, to accurately predict AISMR with a lead time of three months. The fine-tuned PatchTST model, trained with historical AISMR data, the Ni\~no3.4 index, and categorical Indian Ocean Dipole values, outperforms several popular neural network models and statistical models. This fine-tuned LLM model exhibits an exceptionally low RMSE percentage of 0.07% and a Spearman correlation of 0.976. This is particularly impressive, since it is nearly 80% more accurate than the best-performing NN models. The model predicts an above-normal monsoon for the year 2024, with an accumulated rainfall of 921.6 mm in the month of June-September for the entire country.
SEA-ViT: Sea Surface Currents Forecasting Using Vision Transformer and GRU-Based Spatio-Temporal Covariance Modeling
Forecasting sea surface currents is essential for applications such as maritime navigation, environmental monitoring, and climate analysis, particularly in regions like the Gulf of Thailand and the Andaman Sea. This paper introduces SEA-ViT, an advanced deep learning model that integrates Vision Transformer (ViT) with bidirectional Gated Recurrent Units (GRUs) to capture spatio-temporal covariance for predicting sea surface currents (U, V) using high-frequency radar (HF) data. The name SEA-ViT is derived from ``Sea Surface Currents Forecasting using Vision Transformer,'' highlighting the model's emphasis on ocean dynamics and its use of the ViT architecture to enhance forecasting capabilities. SEA-ViT is designed to unravel complex dependencies by leveraging a rich dataset spanning over 30 years and incorporating ENSO indices (El Ni\~no, La Ni\~na, and neutral phases) to address the intricate relationship between geographic coordinates and climatic variations. This development enhances the predictive capabilities for sea surface currents, supporting the efforts of the Geo-Informatics and Space Technology Development Agency (GISTDA) in Thailand's maritime regions. The code and pretrained models are available at \url{https://github.com/kaopanboonyuen/gistda-ai-sea-surface-currents}.
Center-fixing of tropical cyclones using uncertainty-aware deep learning applied to high-temporal-resolution geostationary satellite imagery
Lagerquist, Ryan, Chirokova, Galina, DeMaria, Robert, DeMaria, Mark, Ebert-Uphoff, Imme
Determining the location of a tropical cyclone's (TC) surface circulation center -- "center-fixing" -- is a critical first step in the TC-forecasting process, affecting current and future estimates of track, intensity, and structure. Despite a recent increase in the number of automated center-fixing methods, only one such method (ARCHER-2) is operational, and its best performance is achieved when using microwave or scatterometer data, which are not available at every forecast cycle. We develop a deep-learning algorithm called GeoCenter; it relies only on geostationary IR satellite imagery, which is available for all TC basins at high frequency (10-15 min) and low latency (< 10 min) during both day and night. GeoCenter ingests an animation (time series) of IR images, including 10 channels at lag times up to 3 hours. The animation is centered at a "first guess" location, offset from the true TC-center location by 48 km on average and sometimes > 100 km; GeoCenter is tasked with correcting this offset. On an independent testing dataset, GeoCenter achieves a mean/median/RMS (root mean square) error of 26.9/23.3/32.0 km for all systems, 25.7/22.3/30.5 km for tropical systems, and 15.7/13.6/18.6 km for category-2--5 hurricanes. These values are similar to ARCHER-2 errors when microwave or scatterometer data are available, and better than ARCHER-2 errors when only IR data are available. GeoCenter also performs skillful uncertainty quantification (UQ), producing a well calibrated ensemble of 200 TC-center locations. Furthermore, all predictors used by GeoCenter are available in real time, which would make GeoCenter easy to implement operationally every 10-15 min.
AraDiCE: Benchmarks for Dialectal and Cultural Capabilities in LLMs
Mousi, Basel, Durrani, Nadir, Ahmad, Fatema, Hasan, Md. Arid, Hasanain, Maram, Kabbani, Tameem, Dalvi, Fahim, Chowdhury, Shammur Absar, Alam, Firoj
Arabic, with its rich diversity of dialects, remains significantly underrepresented in Large Language Models, particularly in dialectal variations. We address this gap by introducing seven synthetic datasets in dialects alongside Modern Standard Arabic (MSA), created using Machine Translation (MT) combined with human post-editing. We present AraDiCE, a benchmark for Arabic Dialect and Cultural Evaluation. We evaluate LLMs on dialect comprehension and generation, focusing specifically on low-resource Arabic dialects. Additionally, we introduce the first-ever fine-grained benchmark designed to evaluate cultural awareness across the Gulf, Egypt, and Levant regions, providing a novel dimension to LLM evaluation. Our findings demonstrate that while Arabic-specific models like Jais and AceGPT outperform multilingual models on dialectal tasks, significant challenges persist in dialect identification, generation, and translation. This work contributes ~45K post-edited samples, a cultural benchmark, and highlights the importance of tailored training to improve LLM performance in capturing the nuances of diverse Arabic dialects and cultural contexts. We will release the dialectal translation models and benchmarks curated in this study.
Can the US find new partners in West Africa after Niger exit?
Following 11 years of defence cooperation and millions of dollars spent on maintaining military bases, the United States officially pulled its troops out of Niger this week in a surprise divorce that experts are calling a "blow" to Washington's ambitions for influence in the troubled Sahel region of West Africa. Once-close relations between the two countries saw the US establish large, expensive military bases from which it launched surveillance drones in Niger to monitor myriad armed groups linked to al-Qaeda and ISIL (ISIS). However, those ties collapsed in March when Niger's military government, which seized power in July 2023, cancelled a decade-long security agreement and told the US, which was pushing for a transition to civilian rule, to remove its 1,100 military personnel stationed there by September 15. For months, the US has failed to either fully align with or outright oppose the ruling military, analysts say. On the one hand, Washington seemed ready to maintain defence relations with the new ruling power, but on the other, it felt compelled to denounce the coup and pause aid to Niger.
An Entropy-Based Test and Development Framework for Uncertainty Modeling in Level-Set Visualizations
Sisneros, Robert, Athawale, Tushar M., Pugmire, David, Moreland, Kenneth
We present a simple comparative framework for testing and developing uncertainty modeling in uncertain marching cubes implementations. The selection of a model to represent the probability distribution of uncertain values directly influences the memory use, run time, and accuracy of an uncertainty visualization algorithm. We use an entropy calculation directly on ensemble data to establish an expected result and then compare the entropy from various probability models, including uniform, Gaussian, histogram, and quantile models. Our results verify that models matching the distribution of the ensemble indeed match the entropy. We further show that fewer bins in nonparametric histogram models are more effective whereas large numbers of bins in quantile models approach data accuracy.
Applications of machine learning to predict seasonal precipitation for East Africa
Scheuerer, Michael, Heinrich-Mertsching, Claudio, Bahaga, Titike K., Gudoshava, Masilin, Thorarinsdottir, Thordis L.
Seasonal climate forecasts are commonly based on model runs from fully coupled forecasting systems that use Earth system models to represent interactions between the atmosphere, ocean, land and other Earth-system components. Recently, machine learning (ML) methods are increasingly being investigated for this task where large-scale climate variability is linked to local or regional temperature or precipitation in a linear or non-linear fashion. This paper investigates the use of interpretable ML methods to predict seasonal precipitation for East Africa in an operational setting. Dimension reduction is performed by decomposing the precipitation fields via empirical orthogonal functions (EOFs), such that only the respective factor loadings need to the predicted. Indices of large-scale climate variability--including the rate of change in individual indices as well as interactions between different indices--are then used as potential features to obtain tercile forecasts from an interpretable ML algorithm. Several research questions regarding the use of data and the effect of model complexity are studied. The results are compared against the ECMWF seasonal forecasting system (SEAS5) for three seasons--MAM, JJAS and OND--over the period 1993-2020. Compared to climatology for the same period, the ECMWF forecasts have negative skill in MAM and JJAS and significant positive skill in OND. The ML approach is on par with climatology in MAM and JJAS and a significantly positive skill in OND, if not quite at the level of the OND ECMWF forecast.
How to navigate the green economy: Here are four success stories
No one knows just many green jobs will be created in the United States over the next decade, but there's little disagreement that the demand will create a huge opportunity for the next generation of workers. Thanks to the Inflation Reduction Act of 2022, an estimated 800 billion will flow from the federal government over the next 10 years to fund massive clean energy programs, from solar and wind installations to energy-efficient buildings to business and neighborhood microgrid power production. Billions more in state and federal money will help build out an electrified transportation system, including electric cars, trucks, trains and the infrastructure to support them. High school and university educators are reporting increasing interest in "green" careers: jobs that help address global warming and other environmental issues, with enough of a future to pay the bills and then some. Given the drumbeat of bad news on a changing climate, it might even be considered a matter of survival.
Identity-related Speech Suppression in Generative AI Content Moderation
Anigboro, Oghenefejiro Isaacs, Crawford, Charlie M., Metaxa, Danaë, Friedler, Sorelle A.
Automated content moderation systems have long been used to help reduce the occurrence of violent, hateful, sexual, or otherwise undesired user-generated content online, including in online comment sections and by social media platforms [7, 19, 24]. As content is generated by AI systems, automated content moderation techniques are being applied to the text generated by these systems to filter unwanted content before it is shown to users [21, 22]. However, content moderation is known to suffer from identity-related biases, such that speech by or about marginalized identities is more likely to be incorrectly flagged as inappropriate content [5, 10, 27]. In this paper, we conduct an audit of five content moderation systems to measure identity-related speech suppression, introducing benchmark datasets and definitions to quantify these biases in the context of generative AI systems. Previous assessments of content moderation systems have used benchmark datasets to measure effectiveness and bias. These include datasets composed of user-generated content, such as tweets or internet comments, that have been hand-labeled according to a content moderation rubric [2, 8]. However, most of these datasets are composed of short-form content and do not include the types of text involved in generative AI systems, be they user-generated prompts or system-provided responses. Automated content moderation systems applied in generative AI settings may have unexpected or undesired results, for example flagging PG-rated movie scripts as inappropriate content [21]. As generative AI is increasingly used for creative and expressive text generation from schools to Hollywood, this paper is motivated by this question: whose stories won't be told?