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Title: The Fertilizing Role of African Dust in the Amazon Rainforest. A First Multiyear Assessment Based on Data from Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations

The productivity of the Amazon rainforest is constrained by the availability of nutrients, in particular phosphorus (P). Deposition of long-range transported African dust is recognized as a potentially important but poorly quantified source of phosphorus. This study provides a first multiyear satellite-based estimate of dust deposition into the Amazon Basin using three dimensional (3D) aerosol measurements over 2007-2013 from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP). The 7-year average of dust deposition into the Amazon Basin is estimated to be 28 (8~48) Tg a-1 or 29 (8~50) kg ha-1 a-1. The dust deposition shows significant interannual variation that is negatively correlated with the prior-year rainfall in the Sahel. The CALIOP-based multi-year mean estimate of dust deposition matches better with estimates from in-situ measurements and model simulations than a previous satellite-based estimate does. The closer agreement benefits from a more realistic geographic definition of the Amazon Basin and inclusion of meridional dust transport calculation in addition to the 3D nature of CALIOP aerosol measurements. The imported dust could provide about 0.022 (0.006~0.037) Tg P of phosphorus per year, equivalent to 23 (7~39) g P ha-1 a-1 to fertilize the Amazon rainforest. This out-of-Basin P input is comparable to the hydrological lossmore » of P from the Basin, suggesting an important role of African dust in preventing phosphorus depletion on time scales of decades to centuries.« less
Authors:
 [1] ;  [2] ;  [3] ;  [3] ;  [4] ;  [5] ;  [6] ;  [6] ;  [7] ;  [7] ;  [4] ;  [8]
  1. Univ. of Maryland, College Park, MD (United States); NASA Goddard Space Flight Center (GSFC), Greenbelt, MD (United States)
  2. NASA Goddard Space Flight Center (GSFC), Greenbelt, MD (United States)
  3. NASA Goddard Space Flight Center (GSFC), Greenbelt, MD (United States); Univ. of Maryland, Baltimore, MD (United States)
  4. Univ. of Maryland, Baltimore, MD (United States)
  5. Univ. of Miami, FL (United States)
  6. NASA Langley Research Center, Hampton, VA (United States)
  7. NASA Goddard Space Flight Center (GSFC), Greenbelt, MD (United States); Universities Space Research Association, Columbia, MD (United States)
  8. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Publication Date:
OSTI Identifier:
1225157
Report Number(s):
PNNL-SA--108241
Journal ID: ISSN 0094-8276; KP1703010
DOE Contract Number:
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: Geophysical Research Letters; Journal Volume: 42; Journal Issue: 6
Publisher:
American Geophysical Union
Research Org:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES