A wind-albedo-wind feedback driven by landscape evolution

Jordan T Abell,Gisela Winckler,Andrew R Metcalf,Alex Pullen,Zachary J Lebo,Paul Kapp,Junsheng Nie,Lucas Gloege

doi:10.1038/s41467-019-13661-w

Abstract

The accurate characterization of near-surface winds is critical to our understanding of past and modern climate. Dust lofted by these winds has the potential to modify surface and atmospheric conditions as well as ocean biogeochemistry. Stony deserts, low dust emitting regions today, represent expansive areas where variations in surficial geology through time may drastically impact near-surface conditions. Here we use the Weather Research and Forecasting (WRF) model over the western Gobi Desert to demonstrate a previously undocumented process between wind-driven landscape evolution and boundary layer conditions. Our results show that altered surficial thermal properties through winnowing of fine-grained sediments and formation of low-albedo gravel-mantled surfaces leads to an increase in near-surface winds by up to 25%; paradoxically, wind erosion results in faster winds regionally. This wind-albedo-wind feedback also leads to an increase in the frequency of hours spent at higher wind speeds, which has implications for dust emission potential.

Highlights

The accurate characterization of near-surface winds is critical to our understanding of past and modern climate
Our results indicate that wind erosion and the subsequent production of gravel-dominated surfaces leads to an increase in near-surface winds speeds by up to 25%, as well as increases in surface vertical wind speeds, surface turbulent kinetic energy, and an approximate doubling of the average height of the planetary boundary layer over the spring season
Considerable efforts to validate the control simulation (WRF_Control) are taken to demonstrate that the Weather Research and Forecasting (WRF) model accurately simulates climate conditions during the simulated period over the western Gobi region, including comparison with the forcing data set (NCEP Global Forecast System Analysis (GFS-ANL)), an independent reanalysis product (European Centre for Medium-Range Forecast’s (ECMWF) fifthgeneration atmospheric reanalysis (ERA5))[32], and daily observations at 14 surface point stations using the Integrated Surface Hourly data set collected by the United States Air Force (USAF) Climatology Center[33]

Summary

Introduction

The accurate characterization of near-surface winds is critical to our understanding of past and modern climate. The East Asian dust-producing regions are upwind of a prominent high-nutrient/ low-chlorophyll area in the North Pacific where the productivity of photosynthetic organisms is limited by the concentration of bioavailable Fe within surface waters[9,10,11]. To those ends, understanding winds and dust production in East Asia has significant implications[12]. Stony deserts compose >70% of the total desert area of East Asia, but only account for ~30% of total dust emissions[16]

Methods

Results

Conclusion