This study employs advanced Large Language Models (LLMs) and Dynamic Topic Modeling to quantitatively analyze nearly 290,000 hydrology-related publications from 2000 to 2023. By intelligently parsing hundreds of thousands of global hydrology publications, the research overcomes the limitations of traditional bibliometric methods. It maps the field's trajectory, revealing a crucial thematic shift from traditional water resource management to eco-hydrology. The findings highlight the surging focus on climate change, the widespread use of the hydrological models, and the intense scientific attention on the Yangtze and Yellow River basins. This study provides a comprehensive overview of how the discipline has evolved to meet complex environmental challenges.

This study constructed a Household Heating Burden index to reveal the prevailing unaffordability of rural residential clean heating in 2020 both with and without regional subsidies based on a high-resolution township-level clean heating retrofitting dataset. Phasing out operating subsidies for rural clean heating in northern China would raise household heating spending by 36.2% on average, adding about 523.3 CNY per household. The burden would fall most heavily on lower-income households in parts of Hebei, Henan, Shandong, and Shanxi. Carbon-credit revenues from clean heating under China's voluntary emissions reduction system could offset only a limited share of those added costs, but distributed rooftop photovoltaics show stronger promise. In some areas, rooftop solar could compensate for roughly one-third to nearly two-thirds of the extra heating expense, suggesting that tailored subsidy phase-out plans combined with rural solar deployment could make clean heating more economically sustainable.