The Global Water Cycle

The behavior of water in the Earth System is central to nearly every aspect of the global climate and crucial to human welfare. Interannual changes in precipitation and evaporation are associated with droughts and floods that threaten the lives and livelihood of millions of people. Evidence indicates that the global hydrological cycle is accelerating, resulting in an increasing number of extreme precipitation events. Improving our understanding of the ways that water influences, and is influenced by, the integrated Earth System is a critical component of our ongoing effort to predict climate variations and anticipate global climate change.

ESSIC’s research is oriented toward understanding, monitoring and predicting the global water cycle, including precipitation, evaporation, storage and transport, on time scales from weeks to centuries. This research theme encapsulates the expertises of Hydrometeorology/Precipitation Retrieval and the Cryosphere.

Key questions involving Earth System interactions include:

• • What are the dynamic pathways, storages, transfers and transformations of water within the Earth System, and how do they change in association with seasonal to interannual climate variability?
  • What are the interactions and feedbacks among terrestrial and marine ecosystems, land use and land cover, and the global water and carbon cycles, and how will these evolve as atmospheric CO2 increases?
  • How do regional changes in air pollution affect the local and global behavior of the water cycle?
  • What is our ability to reproduce/assimilate, simulate and/or predict the water cycle and/or its components at global and regional scales using the state-of-the-art models and data assimilation systems?
  • What new observations are needed to improve our understanding of the water cycle?
  • How will the humidity of the stratosphere and upper troposphere change in response to anthropogenic CO2 emissions, and how will these changes influence other aspects of global change?
  • How will global climate change and human activities on land affect the ocean-continental margins, biogeochemistry, ecosystems, and fisheries?
  • What are the connections between land-ocean interactions and human health, and how will they be influenced by global climate change?