Response of Regional Asian Summer Monsoons to the Effect of Reduced Surface Albedo in Different Tibetan Plateau Domains in Idealized Model Experiments

Abstract

The thermal effect of entire Tibetan Plateau (TP) tends to strengthen the South Asian summer monsoon (SASM); however, how does this monsoon component respond to the thermal conditions of different TP domains? How do the thermal condition of entire TP influences other monsoons including the East Asian summer monsoon (EASM) and the Southeast Asian summer monsoon (SEASM)? These questions are addressed by conducting an experiment with the CESM, which is forced by reducing the surface albedo over the plateau by half, from a TP-averaged 0.20 to 0.10, from May to September, and similar experiments for different TP domains. Both observation and model results show that the entire-TP heating intensifies the large-scale Asian monsoon, the SASM, and the EASM, but surprisingly weakens the SEASM. It is also surprising that the TP heating exerts a stronger effect on the EASM than on the SASM. The southern TP (south of 35°N) does not show the strongest impact on the SASM compared to other TP domains and it exerts a weakest impact on the EASM, which is most strongly influenced by the thermal effect of eastern (east of 90°E) and northern TP. The western TP weakens the SEASM as the other domains, while it strengthens other monsoon components. The thermal condition of southern and eastern TP are accompanied by signals of tropical atmospheric response at relatively broader spatial scales, while that of northern TP more apparently leads to a significant wave train extending eastward from the TP to western Eurasia over the higher latitudes.

Interannual Impact of the North Atlantic Tripole SST Mode on the Surface Potential Vorticity Over the Tibetan Plateau During Boreal Summer

“…Theoretical and modeling studies suggested that the relative importance of the thermal and mechanical forcing, which is not the focus of this study, is very sensitive to the strength of the basic flow (Held & Ting, 1990; Held et al., 2002). Moreover, a latest study revealed that the monsoon responses to different heating regions of TP are quite different (Lu et al., 2021). Overall, the TP is an important mechanical and thermal forcing that adjusts the energy and hydrological cycle in the Earth system (Liu et al., 2020).…”

A potential vorticity budget view of the atmospheric circulation climatology over the Tibetan Plateau

“…Therefore, in addition to local circulation, the PV budget view can also be used to investigate the dynamics underlying the remote influences of the TP, especially its surface PV source, on weather and climate. In particular, previous studies suggested that the TP influences the climate of upstream Eurasia and Africa via zonal‐vertical circulation cells and Rossby waves (Lu et al ., 2018; Nan et al ., 2019; Liu et al ., 2020b) and the climates of the Indian Ocean, downstream Asia, Pacific Ocean, North America, and Atlantic Ocean via Rossby waves and meridional‐vertical circulation cells (Wu et al ., 2007; Zhao et al ., 2007; Park et al ., 2013; Sun et al ., 2019; Yang et al ., 2020; You et al ., 2020; Liu et al ., 2020a; Lu et al ., 2021); tropical cyclones (Baldwin et al ., 2019); and weather, including synoptic temperature variability in winter around the TP (Lutsko et al ., 2019), Eurasian heatwaves in summer (Wu et al ., 2015b), and downstream severe weather in China (Wu et al ., 2020; Ma et al ., 2022)…”

Paleolithic occupation of arid Central Asia in the Middle Pleistocene

“…However, the link between Homo erectus and Acheulean bifacial technology is complex [86] and bifaces are notably absent from several other assemblages associated with Homo erectus. Stone tools recovered from Zhoukoudian represent typical core-and-flake industries without bifaces [87][88][89][90][91]. Artifacts were not directly recovered at Kocabaş, Anatolia, although nearby lithics from Bozyer, Anatolia were suggested to be manufactured by Homo erectus [92].…”