Subsurface Temperature and Moisture Measurements over Land (Invited Presentation)

The dynamic state of the terrestrial surface is a key contributor to the development of the planetary boundary layer and associated processes critical to weather and climate.  In particular, soil moisture and temperature modulate the exchange of mass and energy between the land surface and the atmosphere directly through bare soil evaporation and indirectly through the ecosystem via transpiration.  Currently, the spatial and temporal distribution of near real-time soil moisture and temperature observations are limited.  However, advances in multiple methodologies and technologies have provided an ever increasing suite of observations including in situ sensors deployed at surface observing sites (e.g., Mesonets, SCAN, CRN, NEON, etc.), surface-based remote sensing platforms (e.g., COSMOS, GPS), and satellite based radiometers and platforms (e.g., AMSR-E, SMOS, SMAP, etc.).  However, each instrumentation system yields varying sensor accuracies, representativeness (horizontal and vertical across varying land cover and land use types), and observational latency (hours to days). These factors pose significant challenges in directly assimilating subsurface observations of temperature and moisture for use in operational, near real-time numerical weather prediction.  At the same time, such observations are (1) increasingly being used to create more realistic surface analyses relevant for determining the current state of the environmental conditions (e.g., drought conditions) as well as daily, weekly, and seasonal prediction.