Why precipitation variability is challenging (and interesting)

Abstract:

While the average might be the best documented component of precipitation, the variability about this average can at times be more important for many of its effects, including impactful events like floods and droughts. But quantifying precipitation variability and interpreting what it means can present challenges that mean precipitation does not, of which I will provide a perspective in this presentation. Some of these challenges include: precipitation variability is inherently more uncertain than many other characteristics of climate, including mean precipitation, temperature, or temperature variability. The small correlation length scale of precipitation makes most approaches to quantifying its variability highly sensitive to the input data as well as details of the calculation. Some mechanisms that drive precipitation variability are specific to particular frequencies or frequency bands (like the diurnal cycle and ENSO), while others project across a broad range of timescales (like moisture and turbulence). Finally, the shape of the distribution of precipitation is expected to change in response to greenhouse-gas driven warming, due the physics of energy conservation in the climate system and atmospheric dynamics, with implications for precipitation variability.