Inter‐annual and inter‐decadal variability of early‐ and late‐summer precipitation over northeast China and their background circulation

Abstract

Using precipitation data from weather stations in China and reanalysis data from National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR), the inter‐annual and inter‐decadal variability of early‐summer (May–June) and late‐summer (July–August) precipitation (hereinafter referred to as MJP and JAP, respectively) over northeast China (NEC) and their background circulation during 1951–2016 were analysed. The following new findings have been highlighted: (a) There are significantly different inter‐annual and inter‐decadal variability characteristics between MJP and JAP over NEC. The inter‐annual variability of MJP is independent from that of JAP, while the inter‐decadal variability of the former is opposite to that of the latter. A significant shift to more MJP (less JAP) occurred in the early 2000s (late 1990s). (b) In terms of the inter‐annual timescale, the large‐scale atmospheric circulations‐associated MJP is notably different from JAP over NEC. The variation in MJP is mainly dominated by the northeast China low (NECL) and the Okhotsk blocking high (OBH), while JAP is mainly influenced by the western Pacific subtropical high (WPSH), the NEC south wind (NESW), and the NECL. (c) On the inter‐decadal timescale, MJP is associated with the inter‐decadal variation of the East Asia/Pacific (EAP) teleconnection, while JAP is closely related to the inter‐decadal variation of the NECL and NESW. When the EAP is in a positive phase, MJP is more than average. Furthermore in late summer, the strong NECL and NESW are both of benefit to the convergence of water vapour from the tropical southwest and East Asian subtropical westerlies over NEC, which contributes to the more JAP than average.

Oceanic Drivers and Empirical Prediction of Interannual Rainfall Variability in Late Summer Over Northeast China

“…These results are consistent with that of previous studies, which have proposed that NECR is affected mainly by the East Asian subtropical monsoon system (for example, the WNPAC and NEC southerly winds), and the westerly circulation system (such as the NEC cold vortex) in late summer (Fang et al 2018;Shen et al 2011;Zhao et al 2018). Among them, the WNPAC is the dominant factor contributing to the NECR variability by modulating the northward transport of water vapor from the ocean.…”

A Detectable Anthropogenic Shift Toward Intensified Summer Hot Drought Events Over Northeastern China

“…On the interdecadal timescale, summer precipitation is observed to significantly decrease since the end of the 1970s (Ding et al, ; Liu et al, ; Sun & Wang, ), which might be partially linked to the abrupt decrease of preceding winter and spring snows over the Tibetan Plateau (Ding et al, ). In addition, the summer precipitation over NEC also experienced an interdecadal decrease after the end of the 1990s (Zhao et al, ). Similar to changes in precipitation, the summer SAT over NEC experienced a shift toward a warm phase in the early 1990s (Chen & Lu, ).…”

Possible Relationships Between the Interannual Anomalies of the South-North Positions of the Northeastern China Cold Vortexes and the Sea Surface Temperatures (SSTs) During the Early Summer Periods

“…Lu et al (2020) analyzed the spring precipitation levels in the NEC region, and revealed the physical mechanism in which the SSTs of the tropical North Atlantic and the northwestern Pacific Ocean influenced the low value systems over the NEC region during the spring seasons with the characteristics of interannual variability. In addition, other meaningful research investigations have carried out from other relevant aspects (Fang et al, 2017a;Fang et al, 2017b;Zhao et al, 2018;Zhao et al, 2019).…”