05 September 2017

Survey on Large-scale Hydroclimatic Variability Illustrates Complexity, Importance of the Field

A summary of state-of-the-science findings showed recent research to be vibrant and multifaceted; shows depth of future research areas


Analyses of large-scale hydrological variations and the ability to predict them underlie much of the science of hydroclimatology—the study of the hydrological cycle in the context of the global climate system. While much valuable research on hydrology and hydrological prediction still occurs at catchment and smaller scales, a global-scale perspective continues to grow in importance as water scarcity issues increasingly affect populations around the world. Leading researchers in this discipline, including one from the U.S. Department of Energy’s Pacific Northwest National Laboratory, conducted a survey that provides scientists in the field with multiple starting points for further study of large-scale hydroclimatic variability.


Humans have attempted to quantify and manage hydrological variability and its impacts on society for millennia. Over the centuries, reservoirs have been built to provide water to society during dry periods and to serve as a buffer against flooding in pluvial periods. More recently, scientists have devised techniques for quantifying predictions of hydrological variations, such as seasonal streamflow, to inform water management. A recent survey of the state-of-the-science in this field highlights the broad range of topics related to large-scale hydrological variability and provides key examples from the last five years that illustrate the complexity and importance of this area of research.


A large cross section of leading hydrologists and hydroclimatologists met in June 2016 at a symposium in Princeton, New Jersey, to honor the career of Professor Eric Wood, a visionary in the study of hydrologic science. As a result of the symposium, scientists surveyed recent research in large-scale hydroclimatic variability, focusing on five topics: 1) general studies on variability and trends, 2) drought, 3) floods, 4) land-atmosphere coupling, and 5) hydrological prediction. Scientists supplemented each topic with illustrative examples of recent research, as presented at the symposium. The survey emphasizes large-scale research, rather than detailing the extensive work being performed, for example, at or below the catchment scale. For each subtopic, researchers presented state-of-the-science findings dating back to about 2010. Each of these findings appears as a self-contained, stand-alone figure and caption in the report. Together, the collection illustrates the many facets of hydrological variability and the different approaches used to investigate it, as well as insight into areas of importance for future study.

L. Ruby Leung
Pacific Northwest National Laboratory
Koster, R., Betts, A., Kirmeyer, P., et al. "Hydroclimatic Variability and Predictability: A Survey of Recent Research." Hydrology and Earth System Sciences 21, 3777-3798 (2017). [10.5194/hess-21-3777-2017].