Vegetation dynamics and deposition of dust onto snow in the western United States
Abstract
The deposition of desert dust on mountain snow has drawn substantial attention lately, primarily due to the fact that dust deposited on the mountain snowpack can have direct effects on snow hydrology through the snow-albedo feedback. The Four Corners area has some of the highest dust production in the western US. Both geochemical and remote sensing studies have illustrated that dust produced in this area can be transported northeast to be deposited over the mountainous ranges in southwestern Colorado. Historical records show that both the number of events and magnitude of dust deposited on the snow varied substantially. The objective of this study is to link the fluctuation of dust deposition on snow with vegetation dynamics in the dust source area. Two experimental plots were set up in western San Juan Mountains to monitor dust on the snow since spring 2005. A time series of vegetation dynamics, represented here as the unvegetated bare soil exposure, was created by a relative spectral mixture analysis of MODIS reflectance data of titles h08v05 and h09v05, for the period of 2002 to 2011. Our results show that soil exposure anomaly in the dust source area was significantly correlated with end-of-year dust on the snow in the San Juan Mountains, particularly for the period of middle of April to early June. The area of Little Colorado River basin, located in northeastern Arizona, shows the highest concentration pixels with significant correlations. Because this area is known to produce dust that is deposited in the San Juan Mountains, this result provides strong support for the idea that vegetation dynamics provide first-order controls on emission of dust from this source area and deposition of that dust to the San Juan Mountains.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2012
- Bibcode:
- 2012AGUFM.C53C0863L
- Keywords:
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- 0305 ATMOSPHERIC COMPOSITION AND STRUCTURE / Aerosols and particles;
- 0439 BIOGEOSCIENCES / Ecosystems;
- structure and dynamics;
- 0480 BIOGEOSCIENCES / Remote sensing