Untitled DocumentWater, energy and carbon cycling in a southwestern subalpine forest
Macro Theme Area:
River Systems [Project ID: R33]
PI:
Dave Breshears
CO-PI(s):
David Breshears, Travis Huxman
Basin focus:
Regional SW, San Pedro
Specific area in
basin /
field sites:
Mt Bigelow in the Santa Catalina Mountain Range North of Tucson Arizona
Summary/Goals: SAHRA's Mount Bigelow project successfully demonstrated the feasibility of making tower-based measurements of water, energy, and CO2 exchange in high altitude undulating terrain and provided initial evidence of the importance of seasonal water availability on these exchanges. In so doing, it seeded SAHRA's decision to deploy two transects to explore these exchanges, one in the San Pedro and one in the Rio Grande. The Bigelow tower will now transition into being the highest tower site in the SWEON transect. In addition, we will assess associated microclimate conditions associated with mountaneous terrain and amount of tree canopy cover using hemispherical photography.
Activities and outcomes during past year:
Published 2007:
Journal of Arid Environments
Ref: JAE06-34R2
Title: Seasonal Water Dynamics Of A Sky Island Subalpine Forest In
Semi-Arid Southwestern United States
Authors: Constance Brown-Mitic, PhD; William J. Shuttleworth, PhD; R.
Chawm Harlow, PhD; Jonathan R. Petti, BS; Eleanor J. Burke, PhD; Roger
C. Bales, PhD
Remote Data collection is on-going and calculation of CO2 and H2Ov fluxes and precessing of incoming Micro-meteorlogical has been automated through a series of server based scripts. Processed data is automaticly sent into the Sahra database for archiving and made web accessible.
GEOPHYSICAL RESEARCH LETTERS, VOL. 34, L24S21, doi:10.1029/2007GL031484, 2007
Effects of topography and woody plant canopy cover on near-ground solar radiation: Relevant energy inputs for ecohydrology and hydropedology
Chris B. Zou
School of Natural Resources, University of Arizona, Tucson, Arizona, USA
Greg A. Barron-Gafford
Ecology and Evolutionary Biology, University of Arizona, Tucson, Arizona, USA
David D. Breshears
School of Natural Resources, University of Arizona, Tucson, Arizona, USA
Ecology and Evolutionary Biology, University of Arizona, Tucson, Arizona, USA
Institute for the Study of Planet Earth, University of Arizona, Tucson, Arizona, USA
Abstract
The emerging interdisciplinary approaches of ecohydrology and hydropedology are sensitive to variation in soil-surface energy inputs, which are primarily modified by topography and woody plant canopies. Yet a synthesis of the interactive effects of these two modification types is lacking. We systematically estimated near-ground surface solar radiation inputs as modified by key attributes of topography (aspect and slope) and tree cover (degree of openness) using solar radiation modeling based on hemispherical photographs. For south aspects, reductions in annual transmission were dominated by canopy cover rather than topography, even when canopy cover was low, whereas for north aspects, canopy effects dominated the reduction in annual transmission for slopes of up to 10° at low canopy cover and up to 30° at high canopy cover. Our results provide a synthetic perspective of the nonlinear, interactive, and temporally dependent effects of slope, aspect, and amount of canopy cover on near-ground solar radiation.
2006 data is currently being used by Joe Zhender (ASU) in conjunction with the Cupido Project.
Renewed 5 year Permit from the Forest Service
Authorization ID: SUP0027
Type Use: 814 Monitoring Resource Site
Dated: December 31, 2006.
Plans for the upcoming year:
Continued operation of the tower to obtain longer time series/multi year database through a collaborative effort with Biosphere 2. Continued monitoring and modelling efforts on Mt Bigelow, to establish the necessary links between observations and remotely sensed information in order to 1) Improve current models for semi arid subalpine forest dynamics 2) create a template for extending results to the region. Continued evaluation of related microclimate patterns based on tree cover, slope, and aspect.
Organization Involvement:
The CEOP effort will ordinate the acess to satellite information for the mt Bigelow reference site.
Shared Resources / Joint Activities:
The Mt. Bigelow eddy correlation tower is a CEOP high altitude semi arid reference site. As such, SAHRA researh around this site will benefit from the coordinated database that will be acumulated over the next two years intensive observational period.
Organization Involvement:
Collaboration on Funded NSF Profect for the Observation of Cumulus Development over the Santa Catalinas with the SAHRA flux tower as an integral ground observation site.
Shared Resources / Joint Activities:
Instrumentation, data and related activities for the 2004 and 2005 IOP
