Extra-seasonal prediction of summer 500-hPa height field in the area of cold vortices over East Asia with a dynamical-statistical method

Abstract

Extra-seasonal prediction of summer 500-hPa height field in the area of cold vortices over East Asia with a dynamical-statistical method * Zhao Jun-Hu(赵俊虎) a) † , Yang Liu(杨 柳) a)b) , Hou Wei(侯 威) a) , Liu Gang(刘 刚) a)c) , and Zeng Yu-Xing(曾宇星) a)c) a) National Climate Center, China Meteorological Administration, Beijing 100081, China

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

“…The variables include monthly geopotential height ( h ), horizontal wind ( u , v ), and specific humidity. The definition of East Asia/Pacific (EAP) teleconnection index is as follows: EAP = Z 1 − 2 × Z 2 + Z 3 , where Z 1 , Z 2 , and Z 3 represent the normalized average 500‐hPa geopotential height ( H 500 ) within 15°–30°N, 115°–160°E; 55°–65°N, 125°–145°E; and 35°–40°N, 145°–160°E, respectively. Other index data include the Okhotsk blocking high (OBH) index, defined as the area‐averaged H 500 within 55°–65°N, 125°–140°E; the northeast China low (NECL) index, defined as the area‐averaged H 500 within 40°–50°N, 100°–120°E (Zhao et al, ); and the northeast south wind (NESW) index, defined as the area‐averaged 850‐hPa meridional wind ( V 850 ) within 35°–45°N, 120°–130°E (Sun et al, ).…”

“…The large variability of precipitation in northeast China (NEC) is of great importance to the local agriculture and ecosystems (Sun et al, ; Shi and Chen, ; Gao et al, ). Located in the mid to high latitudes, the summer precipitation in NEC is affected by the atmospheric circulation anomalies both in the tropical and extra‐tropical regions, such as blockings in the high latitudes (Yao and Dong, ; Feng et al, ; He et al, ; Zhao et al, ), the northeast cold vortex (NHCV) (He et al, ; Hu et al, ; Zhao et al, ), the East Asian summer monsoon (EASM) (Shi and Zhu, ; Li and Zeng, ; ; Wang, ; Lian et al, ; Sun et al, ), and the western Pacific subtropical high (WPSH) (Shen et al, ; Ding and Chen, ). In addition, numerous studies have indicated that summer precipitation in NEC is also affected by many other external forcing factors, including soil moisture content in northwest Eurasia (Zhu, ), snow cover on the Tibetan Plateau in winter–spring (Shen and Lian, ), and the dipole anomaly of summer Arctic atmospheric variability (Wu et al, ).…”

The Characteristics of Northeast China Cold Vortex With Different Active Paths in June and Their Relationship With Precipitation and Pre-SST

“…Combined with the close relationship between the NCCV and precipitation in China, meteorologists have also carried out extended research and development of summer climate prediction methods (Feng et al, 2001;Fan and Wang, 2010;Gong et al, 2014;Liu and Ren, 2015;Ren et al, 2019). Zhao et al (2015) found that the dynamical-statistical combining principle can more accurately grasp the summer NCCV trend, providing a strong diagnosis basis for precipitation prediction. Liang et al (2009) found through statistical examinations that the spatial distributions of the NCCV are quite different during different seasons.…”

Classification of typical summer rainfall patterns in the East China monsoon region and their association with the East Asian summer monsoon

“…As viewed from the national range, the summer rainfall prediction for the East China monsoon regions focuses on the northern or southern locations of the rain belt (Huang et al 1993;Wang et al 1998;Shi et al 1999;Zhao and Feng 2014;Zhao et al 2015). And the rainfall patterns are strongly influenced by the East Asian summer monsoon (EASM) (Shi and Zhu 1996;Wang 2001;Li and Zeng 2002;Zhu et al 2005;Wang et al 2008;Ding et al 2008;Feng et al 2012;Liu et al 2014).…”