The Seesaw of Seasonal Precipitation Variability Between North China and the Southwest United States: A Response to Arctic Amplification

Abstract

The global surface temperature has increased over the last two centuries in response to forcing resulting from anthropogenic greenhouse gas (GHG) emissions (mainly increases the carbon dioxide [CO 2 ] concentration), with a characteristic pattern of Arctic-amplified-warming, or "Arctic amplification" (Screen & Simmonds, 2010). Previous studies suggested that Arctic amplification is a result of local forcing and feedback (Stuecker et al., 2018). Increased CO 2 forcing is considered as the trigger for global warming in recent centuries (Dai et al., 2019). However, Dai (2021) argues that direct effect of increased CO 2 forcing may decrease Arctic amplification by inducing stronger warming at low latitudes. According to estimates with radiative kernel method (Dai, 2021;Goosse et al., 2018;Graversen et al., 2014;Huang et al., 2017), positive feedback of surface albedo dominates the local forcing and feedback in polar regions (Dai, 2021), which induces large amounts of solar radiation absorption at the sea surface (in polar ocean). Surface temperature

Role of Horizontal Heat Advection in Arctic Surface Warming During Early Spring

“…This mechanism is also verified by numerical results (CTRL and 0.1 A experiments), which have been analyzed in summer, autumn and winter in previous studies (H. Dai, 2021;Dai & Yao, 2023;Dai et al, 2021Dai et al, , 2022. Climate anomalies in the Arctic region of the sensitivity experiment are comparable with those in the observation, although they are much larger in magnitude.…”

“…The Atlantic meridional overturning circulation decreases due to less deep‐water production, which decreases the meridional heat transport and warms the entire Earth's surface. Arctic amplification is achieved (Dai et al., 2021). Both the CTRL and 0.1 A experiments integrate 500 model years.…”

Role of Vertical Mixing in the Upper Ocean in the Seasonal Variation of Arctic Amplification

“…Deep water formation decreases and weakens the Atlantic meridional overturning circulation and meridional heat transport. As a result, more heat is kept at lower latitudes, resulting in global warming (H. Dai, 2021; H. Dai et al., 2021). During the years 1501–2000, 0.1 A is “parallel” to CTRL, with the same initial conditions at the end of year 1500, and it reaches quasi‐equilibrium after the 500‐year integration.…”

“…H. Dai et al (2021) suggested that SRA induced by surface albedo feedback (due to sea-ice loss, Figure 1b, gray line) is the key factor for AA. Incoming solar radiation, which is determined by seasonal displacement of the subsolar point, causes the SRA anomaly to reach its maximum in June (13.7 W/m 2 , Figure 1b, blue line), together with a maximum ice-free region in the Arctic.…”

“…AA strengthens the polar vortex extension to reach lower latitudes and produces a weaker polar vortex, which may lead to the escape of cold air from higher latitudes and the occurrence of extremely cold events in winter (Cohen et al., 2014; Kug et al., 2015). AA also contributes to heat waves (Francis & Vavrus, 2012) and summer precipitation (Coumou et al., 2018; H. Dai et al., 2021; Oudar et al., 2017). On the other hand, AA is suggested to have little impact on the midlatitude climate (Blackport & Screen, 2020; A. Dai & Song, 2020), since the effect of AA can hardly be separated from those of natural variability or background warming.…”