With the boom of a new round of scientific and technological revolution, the National Natural Science Foundation of China (NSFC) has launched the Reform Initiatives in a bid to establish a leading science funding system that is guided by advanced concepts, equipped by a well-established mechanism and operated in a fair and efficient manner. To achieve these goals, the NSFC has identified the funding guidance for the new era, which can be summarized in the following four categories: Funding creative and timely ideas to achieve excellence in science, focusing on the frontiers of science in unique ways to lead the cutting edges, supporting application-driven basic research to enable breakthroughs, and encouraging transdisciplinary leading-edge research to promote convergence. In short, these four categories can be abbreviated as C1, C2, C3 and C4, respectively. The four categories correspond to the NSFC’s four functions. C1 stresses on the “incubator” function. It is researchers’ inspirations and creativities that “incubate” scientific hypotheses. The NSFC highlights their free and initiative exploration that is likely to produce original results from scratch. C2 focuses on the “tractor” function. Based on the existing unsolved problems, new science questions are presented, and the answers to these questions are proposed by overcoming obstacles with unique means, including improved methodologies, technologies and theories. The NSFC aims to support the proposals with pioneering endeavours so as to facilitate cutting-edge development. C3 emphasizes the “driver” function. Science questions tend to be application-driven, problem-driven and goal-driven. Therefore, the NSFC encourages applicants to not only tackle the basic scientific issues behind the technical bottlenecks, but also to convert the research results into applicable practices. C4 underlines the “multiplier” function. Since the nature of science questions is cross- disciplinary, the NSFC is committed to promoting the synergy and convergence of knowledge systems through multi- discipline research. In 2019, the discipline of atmospheric sciences (DAS) was selected as a reform pilot by the NSFC. Facing atmospheric sciences transforming from “traditional meteorology” into “Earth system science”, the DAS has provided interpretations of the above four categories of funding guidance. Regarding C1, levels of originality are regarded as the criterion for the measurement of creativity to open up new frontiers. A reference system was established by the DAS to evaluate originality on five levels, i.e., “motherdisciplines” (the basis of science, e.g., mathematics, physics and chemistry), geosciences, and the first level, the second level and the third level of atmospheric sciences. Regarding C2, the DAS encourages applicants to provide answers to challenging questions targeting the global science frontiers of atmospheric sciences and related areas with novel data/methods/technologies/theories. Regarding C3, the DAS is committed to solving the basic scientific problems deeply rooted in the development of the meteorological industry so as to serve the main economic battlefield, strive to fulfill the significant needs of the country and benefit people’s lives and health. Regarding C4, the DAS promotes trans-, cross-, inter-, and multi-disciplinary studies, not only to extend the knowledge chain of traditional meteorology, but also to generate new research paradigms for common fields. The above interpretation lays a solid foundation for the implementation of the category-specific review. It can be expected that such reform measures will be adopted for the funding process covering a wider scope of proposals in the recent future.