Dynamic Data Assimilation of MPAS-O and the Global Drifter Dataset

In this study, we propose a new method for combining in situ buoy measurements with Earth system models (ESMs) to improve the accuracy of temperature predictions in the ocean. The technique utilizes the dynamics and modes identified in ESMs to improve the accuracy of buoy measurements while still preserving features such as seasonality. Using this technique, errors in localized temperature predictions made by the MPAS-O model can be corrected. We demonstrate that our approach improves accuracy compared to other interpolation and data assimilation methods. We apply our method to assimilate the Model for Prediction Across Scales Ocean component (MPAS-O) with the Global Drifter Program's in-situ ocean buoy dataset.

Coarse-Grain Cluster Analysis of Tensors With Application to Climate Biome Identification

A tensor provides a concise way to codify the interdependence of complex data. Treating a tensor as a d-way array, each entry records the interaction between the different indices. Clustering provides a way to parse the complexity of the data into more readily understandable information. Clustering methods are heavily dependent on the algorithm of choice, as well as the chosen hyperparameters of the algorithm. However, their sensitivity to data scales is largely unknown. In this work, we apply the discrete wavelet transform to analyze the effects of coarse-graining on clustering tensor data. We are particularly interested in understanding how scale effects clustering of the Earth's climate system. The discrete wavelet transform allows classification of the Earth's climate across a multitude of spatial-temporal scales. The discrete wavelet transform is used to produce an ensemble of classification estimates, as opposed to a single classification. Using information theory, we discover a sub-collection of the ensemble that span the majority of the variance observed, allowing for efficient consensus clustering techniques that can be used to identify climate biomes.