Water is fundamental to life on Earth and its phase transitions between the gas, liquid, and solid states dominate the weather, climate, and ecological systems. Precipitation - which converts atmospheric water vapor into rain or snow - is a central element of the global water/energy cycle through its coupling with clouds, water vapor, atmospheric motions, ocean circulation, and land surface processes. Precipitation is also the primary source of freshwater and can have tremendous socio-economical impact associated with extreme weather events such as hurricanes, floods, droughts, and landslides. Accurate and timely knowledge of precipitation characteristics on regional and global scales is essential for understanding how the Earth system operates under changing climatic conditions and for improved societal applications that range from numerical weather prediction to freshwater resource management.

This session will host papers on all aspects of precipitation, especially contributions in the following four research areas:

Precipitation Measurement:
Precipitation measurements (amount, duration, intensity etc) by ground-based in situ sensors (e.g., rain gauges, disdrometers); estimation of accuracy of measurements, comparison of instrumentation.

Precipitation Climatology:
Regional and global climatology; areal distribution of measured precipitation; classification of precipitation patterns; spatial and temporal characteristics of precipitation; methodologies adopted and their uncertainties; comparative studies.

Precipitation Remote Sensing:
Remote sensing of precipitation (spaceborne, airborne, ground-based, underwater, or shipborne sensors); methodologies to estimate areal precipitation (interpolation, downscaling, combination of measurements and/or estimates of precipitation); methodologies used for the estimation (e.g., QPE), validation, and assessment of error and uncertainty of precipitation as estimated by remote sensors. A special focus will be on international contributions to the preparation of the international Global Precipitation Measurement (GPM) mission to provide the next-generation precipitation estimates (including solid precipitation) from space with unprecedented accuracy and time-space coverage.

Precipitation Modeling:
Quantitative precipitation forecasts from numerical weather prediction models including ensemble forecast of precipitation and probabilistic approaches; verification of precipitation forecasts using different techniques (e.g., gridded and object oriented); quantitative precipitation nowcasting with radar data, satellite and numerical models.