The seasonal variability in rainfall duration, intensity, and volume due to the North American Monsoon Season (NAMS) has been well documented in southwestern American semiarid landscapes. The characteristic high intensity convective NAMS storm systems during the months of June-September lead to a greatly altered land surface in terms of soil moisture and vegetation. However, large-scale investigation of the effects of land-surface changes on hydrometeorological processes within the NAMS reg
ion has minimal associated research to this point. It is our objective to characterize the Tromble Weir watershed within the Jornada Experimental Range in order to better understand the role of land surface conditions on the propagation of the NAMS. In particular, this study investigates the impact of land-surface heterogeneity on eddy covariance tower measurements. We rely on the use of an eddy covariance tower present at the Tromble Weir watershed as well as a series of soil moisture and temperature probes under various land surface conditions distributed in the area near the tower. This study will assess and improve the implementation of the eddy covariance technique in heterogeneous landscapes like those at the Jornada Experimental Range.
This research includes 3 hydrometeorological stations, 3 H-flumes with pressure transducers, and one meteorological flux tower. Hillslope transects are run from each of the hydrometeorological stations in order to assess local spatial variations in soil moisture and temperature. The equipment deployments utilized in this study will allow for watershed scale characterization of soil energy flux, rainfall, soil moisture, and streamflow, and how feedbacks between these parameters and seasonal land cover changes in vegetation are affected by NAMS hydrometeorological processes. This study is the first of a multi-year watershed characterization project which will include 3 separate watersheds1 over 5 consecutive summers. The deployment of this dense observation network in multiple semi-arid basins will allow for cross-NAMS region comparisons of hydrometeorological responses to the seasonal evolution of land-cover changes through the application of a coupled hydrometeorological modeling system. It will also allow for the forecasting of how land-surface may change the hydrometeorological responses of basins within the NAMS region.
1We will be focusing on primarily three sites: at the Jornada, at the Santa Rita Experimental Range in southern Arizona, and at the Sevilleta National Wildlife Refuge in southern New Mexico.