Spatial partitioning of terrestrial precipitation reveals varying dataset agreement across different environments

The study of the water cycle at planetary scale is crucial for our understanding of large-scale climatic processes. However, very little is known about how terrestrial precipitation is distributed across different environments. In this study, we address this gap by employing a 17-dataset ensemble to provide, for the first time, precipitation estimates over a suite of land cover types, biomes, elevation zones, and precipitation intensity classes. We estimate annual terrestrial precipitation at approximately 114,000 +/- 9400 km3, with about 70% falling over tropical, subtropical and temperate regions. Our results highlight substantial inconsistencies, mainly, over the arid and the mountainous areas. To quantify the overall discrepancies, we utilize the concept of dataset agreement and then explore the pairwise relationships among the datasets in terms of "genealogy", concurrency, and distance. The resulting uncertainty-based partitioning demonstrates how precipitation is distributed over a wide range of environments and improves our understanding on how their conditions influence observational fidelity. A total of 114,000 +/- 9,400 km3 of precipitation falls on land each year with high dataset consensus over tropical, subtropical, and temperate regions, and low agreement over arid and mountain regions, according to an analysis of 17 precipitation datasets over the period 2000-2019.