On the probabilistic structure of water age


Journal Article

© 2015. American Geophysical Union. All Rights Reserved. The age distribution of water in hydrologic systems has received renewed interest recently, especially in relation to watershed response to rainfall inputs. The purpose of this contribution is first to draw attention to existing theories of age distributions in population dynamics, fluid mechanics and stochastic groundwater, and in particular to the McKendrick-von Foerster equation and its generalizations and solutions. A second and more important goal is to clarify that, when hydrologic fluxes are modeled by means of time-varying stochastic processes, the age distributions must themselves be treated as random functions. Once their probabilistic structure is obtained, it can be used to characterize the variability of age distributions in real systems and thus help quantify the inherent uncertainty in the field determination of water age. We illustrate these concepts with reference to a stochastic storage model, which has been used as a minimalist model of soil moisture and streamflow dynamics.

Full Text

Duke Authors

Cited Authors

  • Porporato, A; Calabrese, S

Published Date

  • May 1, 2015

Published In

Volume / Issue

  • 51 / 5

Start / End Page

  • 3588 - 3600

Electronic International Standard Serial Number (EISSN)

  • 1944-7973

International Standard Serial Number (ISSN)

  • 0043-1397

Digital Object Identifier (DOI)

  • 10.1002/2015WR017027

Citation Source

  • Scopus