Features of the large-scale circulation of the extremely heavy rain with severe floods over South China in June 2005 and its possible cause

2008 ◽  
Author(s):  
Lijuan Wang ◽  
Zhaoyong Guan ◽  
Chunhua Shi ◽  
Jiang Tao ◽  
Lianji Jin
Keyword(s):  
South China ◽  
Large Scale ◽  
Heavy Rain ◽  
Large Scale Circulation ◽  
Possible Cause

Large-Scale Circulation Anomalies and Intraseasonal Oscillations Associated with Long-Lived Extreme Heat Events in South China

2017 ◽  
Vol 31 (1) ◽  
pp. 213-232 ◽  
Author(s):  
Ruidan Chen ◽  
Zhiping Wen ◽  
Riyu Lu
Keyword(s):  
South China ◽  
Large Scale ◽  
Eastern China ◽  
Intraseasonal Oscillation ◽  
Extreme Heat ◽  
Western Pacific ◽  
Large Scale Circulation ◽  
Extreme Heat Events ◽  
Circulation Anomalies ◽  
The Western Pacific

Abstract South China experiences extreme heat (EH) most frequently in eastern China. This study specifically explores the large-scale circulation anomalies associated with long-lived EH events in south China. The results show that there is an anomalous cyclone (anticyclone) and active (inactive) convection over south China (the western Pacific) before the EH onset; then, an anticyclone develops and moves northwestward and dominates over south China on the onset day. The anomalous anticyclone maintains its strength over south China and then diminishes and is replaced by another cyclone migrating from the western Pacific after the final day of the EH event. Consequently, the temperature increases over south China around the onset day and is anomalously warm for approximately 10 days on average and then decreases shortly thereafter. The fluctuating anomalies over south China and the western Pacific are intimately related to two intraseasonal oscillation (ISO) modes, namely, the 5–25- and 30–90-day oscillations, which originate from the tropical western Pacific and propagate northwestward. The 5–25-day oscillation is vital to triggering and terminating EH, accounting for approximately half of the original temperature and circulation anomaly transitions. The 30–90-day oscillation favors the persistent warming during EH events, accounting for approximately one-third of the original prolonged warming and anticyclonic anomaly. This result suggests that different ISO modes play crucial roles at different stages of the events. Moreover, a higher annual frequency of long-lived EH days in south China is associated with the transition phase from El Niño to La Niña. It is suggested that both medium-range and interannual forecasting of long-lived EH in south China are possible.

scholarly journals Characteristics of Large-Scale Circulation Affecting the Inter-Annual Precipitation Variability in Northern Sumatra Island during Boreal Summer

Atmosphere ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 136
Author(s):  
Yahya Darmawan ◽  
Huang-Hsiung Hsu ◽  
Jia-Yuh Yu
Keyword(s):  
Large Scale ◽  
Precipitation Variability ◽  
Specific Humidity ◽  
Boreal Summer ◽  
Moisture Budget ◽  
Large Scale Circulation ◽  
Budget Analysis ◽  
Sumatra Island ◽  
Precipitation Anomalies ◽  
The Impact

This study aims to explore the contrasting characteristics of large-scale circulation that led to the precipitation anomalies over the northern parts of Sumatra Island. Further, the impact of varying the Asian–Australian Monsoon (AAM) was investigated for triggering the precipitation variability over the study area. The moisture budget analysis was applied to quantify the most dominant component that induces precipitation variability during the JJA (June, July, and August) period. Then, the composite analysis and statistical approach were applied to confirm the result of the moisture budget. Using the European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Anaysis Interim (ERA-Interim) from 1981 to 2016, we identified 9 (nine) dry and 6 (six) wet years based on precipitation anomalies, respectively. The dry years (wet years) anomalies over the study area were mostly supported by downward (upward) vertical velocity anomaly instead of other variables such as specific humidity, horizontal velocity, and evaporation. In the dry years (wet years), there is a strengthening (weakening) of the descent motion, which triggers a reduction (increase) of convection over the study area. The overall downward (upward) motion of westerly (easterly) winds appears to suppress (support) the convection and lead to negative (positive) precipitation anomaly in the whole region but with the largest anomaly over northern parts of Sumatra. The AAM variability proven has a significant role in the precipitation variability over the study area. A teleconnection between the AAM and other global circulations implies the precipitation variability over the northern part of Sumatra Island as a regional phenomenon. The large-scale tropical circulation is possibly related to the PWC modulation (Pacific Walker Circulation).

scholarly journals 2016 Monsoon Convection and its place in the Large-Scale Circulation using Doppler Radars

2021 ◽  
Author(s):  
Alexander John Doyle ◽  
Thorwald Hendrik Matthias Stein ◽  
Andrew Turner
Keyword(s):  
Large Scale ◽  
Large Scale Circulation
Sign in / Sign up

Export Citation Format

Share Document