Submitted to: American Geophysical Union
Publication Type: Abstract Only
Publication Acceptance Date: December 27, 2001
Publication Date: N/A
In order to better understand and monitor the total Earth system, to learn how it is changing, and to predict the effects of changes on the global environment the HYDROS - the Hydrosphere State Exploratory Mission - is proposed to investigate two high-priority science questions about the Earth system: (1) How are global precipitation, evaporation, and the cycling of water changing? and (2) How do ecosystems respond to and affect global environmental change and the carbon cycle? HYDROS will provide global observations of the Earth's changing soil moisture and surface freeze/thaw conditions, which together define the land hydrosphere state. Knowledge of this state is vital to understanding the Earth system cycling of water, energy, and carbon because fluxes of these quantities at the land- atmosphere boundary are strongly influenced by a surface resistance that is linked to the soil moisture and surface freeze/thaw condition. This resistance exerts the primary control on evaporation, transpiration, and carbon exchange over most of the global land surface and, hence, is a fundamental determinant of the global water, energy and carbon cycles. The characteristics of a space-borne and high-resolution mapping system is presented. The baseline mission builds on the heritage of ground-based and airborne passive and active low-frequency microwave measurements that have demonstrated and validated the effectiveness of the measurements.