Precipitation is a key hydrologic flux controlling the coupling between the water and energy cycles and their response under a changing climate, as well as the storage, movement, and quality of water across space-time scales. However, precipitation is challenging to characterize and estimate because of its wide spatiotemporal variability in quantity, intensity, duration, physical state, and processes.
The AGU Precipitation Technical Committee brings together hydrologists, atmospheric scientists, and mathematicians to collectively address critical gaps in our knowledge of precipitation processes, as a primary source of freshwater and a driver of natural hazards, its impacts on hydrology and related uncertainties in weather predictions and climate projections.
These gaps include:
  1. accurate and consistent observations and model estimates of precipitation characteristics on a global scale and with sufficiently high spatial and temporal resolution;
  2. the detection and quantification of phase and process changes at convective and orographic scales at which precipitation triggers natural hazard;
  3. estimation of snow accumulation and its spatial distribution in mountainous regions;
  4. closure of the water balance from headwater catchments to continental-scale river basins.

Key science questions are:

• How does a changing climate impact the physical processes related to precipitation and, in turn, its space-time distribution, rates (including extremes), and phases?
• How does precipitation interact with other Earth System processes in the water and energy cycles?
• How do local and regional society and ecosystems respond to precipitation variability and change?