Amazonian drought – does the SeaWinds scatterometer active microwave data contain a signal?
Tom
Milliman, University of New Hampshire, thomas.milliman@unh.edu
(Presenting)
Steve
Frolking, University of New Hampshire, steve.frolking@unh.edu
(Presenting)
Mark
Fahnestock, University of New Hampshire, mark.fahnestock@unh.edu
A strong drought occurred in southwestern Amazonia in 2005 (Maerngo et al. 2008), and the passive optical/NIR record of this drought’s impact on the forest, as observed by MODIS, has been interpreted in different ways (Saleska et al. 2007; Samanta et al. 2010-in press). Interpretation of the optical/NIR signal is compromised by variable atmospheric aerosol depths and frequently obscured by clouds. The sensitivity of neotropical evergreen broadleaf forests to drought is still not well-known. We analyze nine years (2000-2008) of active microwave backscatter collected by SeaWinds on QuikScat (Ku-band; f = 13.4 GHz, λ = 2.24 cm) over northern South America, using data from the NASA Scatterometer Climate Record Pathfinder project at Brigham Young University (http://www.scp.byu.edu/). We analyzed both horizontally (HH) and vertically (VV) polarized backscatter, developing a 9-year climatologies of each and of the difference between ascending (morning overpass) and descending (eveningoverpass) at a minimum spatial resolution of ~ 4.5 km, and a minimum temporal resolution of 4 days. In parallel to the MODIS analyses of Saleska et al. (2007) and Samanta et al. (2010-in press), we compute a ‘full-record’ backscatter climatology (2000-2008) and then look at spatial and temporal patterns in seasonal anomalies from this climatology for a signal of the 2005 drought relative to other years.
Presentation Type: Poster
Poster Session: Ecosystems Science
NASA TE Funded Awards Represented:
Frolking, Steve
Imaging Impacts of Seasonal Water Stress on Vegetation at Basin to Regional Scales: Combining Optical and Microwave Remote Sensing with Hydrological Measurements to Understand Change