EBCC v0.2: error-bounded compression for weather and climate applications

Abstract. As the resolution of weather and climate simulations increases, the amount of data produced is growing rapidly from hundreds of terabytes to tens of petabytes. These data volumes limit broader adoption, and their continued growth will soon exhaust available storage capacity. To address this problem, we present EBCC v0.2 (Error Bounded Climate-data Compressor). EBCC follows a two-layer compression approach: a base layer using JPEG2000 to capture the bulk of the data at high compression ratios, and a residual layer storing sparse wavelet coefficients to eliminate long-tail extreme errors efficiently. It supports three-dimensional chunks through a multicomponent transform (MCT) in the base layer. To achieve error bounded compression, we introduce error-bound-aware rate allocation in the JPEG2000 base layer. It selects coding passes to approximately satisfy the error target while optimizing the trade-off between compression ratio and mean squared error. We evaluate EBCC alongside established compression methods on benchmarks relevant to weather and climate science, including error statistics, sequential and parallel throughput tests, case studies of primitive and derived variables near a tropical cyclone, an analysis of global energy-budget closure, and a Lagrangian air-parcel trajectory simulation. EBCC either outperforms or closely follows the strongest existing baseline across these benchmarks at relative error targets ranging from 0.01 % to 10 %, achieving compression ratios from 15x to more than 300x. In the energy-budget-closure and Lagrangian-trajectory benchmarks, EBCC achieves more than 100x compression while keeping compression-induced errors below an assimilation-uncertainty reference derived from the ERA5 uncertainty ensemble. These results demonstrate that EBCC can produce heavily compressed weather and climate datasets suitable for downstream applications.