A Quantitative Model‐Based Assessment of Stony Desert Landscape Evolution in the Hami Basin, China: Implications for Plio‐Pleistocene Dust Production in Eastern Asia

Abstract

Dust plays an important role in climate, and while our current representation of dust production includes shifts in vegetation, soil moisture, and ice cover, it does not account for the role of landscape evolution. Here, we use the Weather Research and Forecasting model coupled to an aerosol chemistry model to quantify the effects of arid landscape evolution on boundary layer conditions, dust production, and radiative properties in the Hami Basin, China, a dynamic stony desert in eastern Asia. Relative to today, altered surface roughness, sediment erodibility, and albedo combine to produce up to a~44% increase in wind speeds (mean ≈ 15%), up to a~59% increase in dust loading (mean ≈ 30%), and up to a~4.4 W m −2 increase in downwelling radiation (mean ≈ 2.4 W m −2) over the Hami Basin. Our modeling results, along with geomorphological data for the western Gobi Desert, provide evidence that stony deserts acted as important Plio-Pleistocene dust sources. Plain Language Summary Dust from the breakdown of rocks and minerals plays an important role in Earth's atmosphere by absorbing or scattering incoming solar radiation, and by seeding clouds. Once deposited, iron-rich dust can fertilize surface ocean waters and terrestrial soils for the growth of organisms, making dust important in the global carbon cycle. Because of its role in modifying Earth's climate, we must accurately understand ancient dust production. To test the hypothesis that past changes in dust production impacted climate, we altered the surface properties of the western Gobi Desert, a location that had a very different landscape thousands to millions of years ago, and simulated changes in wind and dust using a regional climate model. We found that this area would have experienced increased wind speeds by up to~40%, increased dust loading by up to~60%, and substantially altered incoming solar radiation in response to land surface evolution.

From Desiccation to Re‐Integration of the Yellow River Since the Last Glaciation

“…Depending on the amount of exported material, this supposition might contrast with the traditional view that dust delivered to the North Pacific Ocean across a variety of timescales is primarily from Central and East Asian deserts active today (J. Sun et al., 2001; Yoon et al., 2019); a finding that is consistent with other studies from across Central and East Asia (Abell et al., 2020; Kapp et al., 2011; Pullen et al., 2011; D. Zhang et al., 2022). Overall, this is just another example that demonstrates how the use of modern conditions as a template to interpret past environments, while sometimes pertinent, may result in incorrect conclusions (Belanger et al., 2016; Nie et al., 2015; Stevens et al., 2010; Willenbring & Von Blanckenburg, 2010).…”

“…Depending on the amount of exported material, this supposition might contrast with the traditional view that dust delivered to the North Pacific Ocean across a variety of timescales is primarily from Central and East Asian deserts active today (J. Sun et al, 2001;Yoon et al, 2019); a finding that is consistent with other studies from across Central and East Asia (Abell et al, 2020;Kapp et al, 2011;Pullen et al, 2011;D. Zhang et al, 2022).…”

Quantifying Late Pleistocene to Holocene Erosion Rates in the Hami Basin, China: Insights Into Pleistocene Dust Dynamics of an East Asian Stony Desert

“…An example are the competing effects of albedo change and surface roughness. Solar radiative heating of the dark‐colored surface could increase the steep temperature and pressure gradients between the Tian Shan to the north and the Hami Basin to the south, enhancing wind speeds (Abell, Pullen, et al., 2020), but the same coalescence of unconsolidated gravels would lead to increased roughness, decreasing winds speeds and thus erosion (e.g., Abell, Rahimi, et al., 2020; Vautard et al., 2010).…”

“…We can use this process of landscape evolution, a general understanding of East Asian climate variability, our newly determined average erosion rate for the last ∼11–23 ky, and a published late Pleistocene alluvial terrace chronostratigraphy and erosion rate to expand upon a previously formulated late Pleistocene history of erosion and dust production in the Hami Basin (Abell, Rahimi, et al., 2020; D. Zhang et al., 2020). During interglacials, a generally warmer and wetter climate persisted, and alluvial terrace deposition dominated (Figure 4a).…”

“…As such, it is reasonable that a majority of previous studies of wind erosion in East Asia predominately focus on three areas; the Qaidam Basin (e.g., Kapp et al., 2011; Rohrmann et al., 2013; Wu et al., 2019), the Tarim Basin (e.g., Dong et al., 2012; Xia, 1987) and the larger Gobi Desert (e.g., Cui et al., 2019; Wang et al., 2011), all of which are important sources of dust today (Prospero et al., 2002) or during glacial periods (Kapp et al., 2011). However, few studies have focused on quantifying wind erosion in the stony deserts of East Asia (Wang et al., 2019), despite their expansive presence and potential for dust generation in the Plio‐Pleistocene (Abell, Rahimi, et al., 2020; Zhang et al., 2020).…”