Observed positive vegetation-rainfall feedbacks in the Sahel dominated by a moisture recycling mechanism
Classic, model-based theory of land-atmosphere interactions across the Sahel promote positive vegetation-rainfall feedbacks dominated by surface albedo mechanism. However, neither the proposed positive vegetation-rainfall feedback nor its underlying albedo mechanism has been convincingly demonstrated using observational data. Here, we present observational evidence for the region’s proposed positive vegetation-rainfall feedback on the seasonal to interannual time scale, and find that it is associated with a moisture recycling mechanism, rather than the classic albedo-based mechanism. Positive anomalies of remotely sensed vegetation greenness across the Sahel during the late and post-monsoon periods favor enhanced evapotranspiration, precipitable water, convective activity and rainfall, indicative of amplified moisture recycling. The identified modest low-level cooling and anomalous atmospheric subsidence in response to positive vegetation greenness anomalies are counter to the responses expected through the classic vegetation-albedo feedback mechanism. The observational analysis further reveals enhanced dust emissions in response to diminished Sahel vegetation growth, potentially contributing to the positive vegetation-rainfall feedback.
- Univ. of Wisconsin, Madison, WI (United States). Nelson Inst. Center for Climatic Research; California Inst. of Technology (CalTech), Pasadena, CA (United States). Jet Propulsion Lab.
- Univ. of Wisconsin, Madison, WI (United States). Nelson Inst. Center for Climatic Research
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Environmental Sciences Division. Climate Change Science Inst.
- Publication Date:
- Grant/Contract Number:
- Accepted Manuscript
- Journal Name:
- Nature Communications
- Additional Journal Information:
- Journal Volume: 8; Journal ID: ISSN 2041-1723
- Nature Publishing Group
- Research Org:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Univ. of Wisconsin, Madison, WI (United States)
- Sponsoring Org:
- USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23); National Science Foundation (NSF)
- Country of Publication:
- United States
- 54 ENVIRONMENTAL SCIENCES; atmospheric dynamics; hydrology
- OSTI Identifier: