Multiscale Variability of Meiyu and Its Prediction: A New Review

Abstract

Following the description of the basic climatic characteristics of Meiyu in East Asia, we present a comprehensive review of multi–time scale variabilities of the Meiyu together with the long‐term change of extreme precipitation during the Meiyu in this paper. The dynamic prediction skills of the Meiyu on subseasonal to seasonal time scales are further described and illustrated by using present numerical prediction models. For the multi–time scale variabilities of the East Asian Meiyu, they are closely related with the impacts of both quasi‐biweekly and 30–60 day oscillation from both the tropics and the middle and high latitudes on intraseasonal time scale, the influences of El Niño–Southern Oscillation and the Tropospheric Biennial Oscillation on interannual time scale, the variations of East Asian summer monsoon on decadal time scale, and the continued impacts of global warming, Pacific Decadal Oscillation and the Atlantic Multidecadal Oscillation on interdecadal scale and long‐term trend. Under the background of the global warming and the influences of urbanization and aerosol effects, the Meiyu shows some specific characteristics including significantly weakened continuous rain, uneven spatial distribution of precipitation, and increased (decreased) number of strong (weak) precipitation days. Improvements of prediction on rain belt location, total precipitation amount, persistent heavy precipitation events, and low‐frequency variability oscillation during Meiyu season have been achieved with the improved dynamic models of the Beijing Climate Center since 2010.

Define East Asian Monsoon Annual Cycle via a Self‐Organizing Map‐Based Approach

“…Thus, applying the SOM approach on the 850-hPa wind fields to derive the monsoon annual cycle could be useful for the operational monsoon forecasting. In addition, previous studies suggested that climate forcings, such as the El Niño-Southern Oscillation (Ding et al, 2020;Okada et al, 2017), sea surface temperature anomalies in the tropical Indian Ocean (He & Zhu, 2015) and greenhouse warming (Kitoh et al, 2013) could cause early or late onset of East Asian monsoon in past or future climates, which will be explored in our future work.…”

Record‐Breaking Meiyu Rainfall Around the Yangtze River in 2020 Regulated by the Subseasonal Phase Transition of the North Atlantic Oscillation

“…However, the extremely enhanced Meiyu rainfall can induce severe flooding and cause great damage in East Asian countries. Therefore, the multiscale variability of Meiyu activity and its prediction has become one of the most important issues in these countries (Chen et al, 2017;Ding et al, 2020;Liu et al, 2020).…”

“…Wang et al, 2018). On a subseasonal timescale, the intraseasonal oscillation (ISO) of the EASM is most crucial for Meiyu activity (Ding et al, 2020;Huang et al, 2019;Lau et al, 1988;Li et al, 2015;Song et al, 2016;B. Wang & Xu, 1997;C.…”

“…The year‐to‐year variation in Meiyu rainfall depends not only on the El Niño–Southern Oscillation (ENSO) and its resultant SST anomaly in the Indian Ocean (Kosaka et al, 2011; B. Wang et al, 2013) but also on the middle‐high‐latitude wave trains over the Eurasian continent (H. Hsu & Lin, 2007; Liu, Ke, & Ding, 2019; Z. Wang et al, 2018). On a subseasonal timescale, the intraseasonal oscillation (ISO) of the EASM is most crucial for Meiyu activity (Ding et al, 2020; Huang et al, 2019; Lau et al, 1988; Li et al, 2015; Song et al, 2016; B. Wang & Xu, 1997; C. Zhu et al, 2003). Moreover, the subseasonal variation of Meiyu rainfall is modulated by the Madden‐Julian Oscillation (MJO) (X. Li et al, 2018) or the summer North Atlantic Oscillation (NAO) (Bollasina & Messori, 2018).…”

Characteristics of Meiyu Seen From Multiple Observational Analyses and Reanalyses

“…Meiyu is an important part of the East Asian monsoon system (e.g., Huang et al, 2011;Yu et al, 2015;Zheng et al, 2013) and the rainfall during the Meiyu period accounts for about 45% of the total summer rainfall (e.g., Ding & Chan, 2005). The amount of the Meiyu precipitation directly affects the flood and drought conditions in the Jianghuai Basin and influences the economic and social production of the region (e.g., Ding et al, 2020).A large portion of Meiyu rain belt is located over the ocean, limiting its direct observation. Many studies on Meiyu were carried out using observational data from weather stations to examine its climatology, interannual and interdecadal variability, and changes (e.g., Ge et al, 2008) and to analyze Meiyu's large-scale circulation features and connections with the underlying surface (e.g., S.-P. Xie & Sampe, 2010) and so on.…”