Deforestation strengthens atmospheric transport of mineral dust and phosphorus from North Africa to the Amazon

Journal Article · Wed May 05 00:00:00 EDT 2021 · Journal of Climate

DOI:https://doi.org/10.1175/jcli-d-20-0786.1· OSTI ID:1850957

Li, Yue ^[1]; Randerson, James T. ^[2]; Mahowald, Natalie M. ^[3]; Lawrence, Peter J. ^[4]

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1. Univ. of California, Irvine, CA (United States). Dept. of Earth System Science; Univ. of California, Irvine, CA (United States)
2. Univ. of California, Irvine, CA (United States). Dept. of Earth System Science
3. Cornell Univ., Ithaca, NY (United States). Dept. of Earth and Atmospheric Sciences
4. National Center for Atmospheric Research (NCAR), Boulder, CO (United States). Climate and Global Dynamic Lab.

Phosphorus contained in atmospheric mineral dust aerosol originating from Africa fertilizes tropical forests in Amazonia. However, the mechanisms influencing this nutrient transport pathway remain poorly understood. Here we use the Community Earth System Model to investigate how large-scale deforestation affects mineral dust aerosol transport and deposition in the tropics. We find that the surface biophysical changes that accompany deforestation produce a warmer, drier and windier surface environment that perturbs atmospheric circulation and enhances long-range dust transport from North Africa to the Amazon. Tropics-wide deforestation weakens the Hadley circulation, which in turn, leads to a northward expansion of the Hadley cell and increases surface air pressure over the Sahara Desert. Additionally, the high pressure anomaly over the Sahara, in turn, increases northeasterly winds across North Africa and the tropical North Atlantic Ocean, which subsequently increases dust transport to the South America continent. We estimate that the annual atmospheric phosphorus deposition from dust significantly increases by 27% (P < 0.01) in the Amazon under a scenario of complete deforestation. These interactions exemplify how land surface changes can modify tropical nutrient cycling, which in turn, may have consequences for long-term changes in tropical ecosystem productivity and biodiversity.

• Research Organization: Cornell Univ., Ithaca, NY (United States); Univ. of California, Irvine, CA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Biological and Environmental Research (BER)
• Grant/Contract Number: SC0006791; SC0021302
• OSTI ID: 1850957
• Journal Information: Journal of Climate, Journal Name: Journal of Climate Journal Issue: 15 Vol. 34; ISSN 0894-8755
• Publisher: American Meteorological Society
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
54 ENVIRONMENTAL SCIENCES
Aerosols
Amazon region
Deforestation
Dust or dust storms
Hadley circulation
Meteorology &amp; Atmospheric Sciences
Tropics