Spatiotemporal structure of the moisture sources feeding heavy precipitation events over the Sichuan Basin

2015 ◽  
Vol 36 (10) ◽  
pp. 3446-3457 ◽  
Author(s):  
Chen Bin ◽  
Xu Xiang-De
Keyword(s):  
Sichuan Basin ◽  
Heavy Precipitation ◽  
Spatiotemporal Structure ◽  
Moisture Sources ◽  
The Sichuan Basin ◽  
Precipitation Events

A Diagnosis of the 1979–2005 Extreme Rainfall Events in the Southeastern United States with Isentropic Moisture Tracing

2010 ◽  
Vol 138 (4) ◽  
pp. 1172-1185 ◽  
Author(s):  
Steven C. Chan ◽  
Vasubandhu Misra
Keyword(s):  
United States ◽  
Land Surface ◽  
Southeastern United States ◽  
Extreme Rainfall ◽  
Heavy Precipitation ◽  
Extreme Rainfall Events ◽  
Moisture Sources ◽  
Precipitation Total ◽  
Precipitation Anomalies ◽  
Precipitation Events

Abstract A detailed analysis is performed to better understand the interannual and subseasonal variability of moisture sources of major recent dry (1980, 1990, and 2000) and wet (1994, 2003, and 2005) June–August (JJA) seasons in the southeastern United States. Wet (dry) JJAs show an increased (decreased) standard deviation of daily precipitation. Whereas most days during dry JJAs have little or no precipitation, wet JJAs contain more days with significant precipitation and a large increase of heavy (+10 mm) precipitation days. At least two tropical cyclone/depression landfalls occur in the southeastern United States during wet JJAs, whereas none occur during dry JJAs. The trajectory analysis suggests significant local recycling of moisture, implying that land surface feedback has the potential to enhance (suppress) precipitation anomalies during a wet (dry) JJA. Remote moisture sources during heavy precipitation events are very similar between wet and dry JJAs. The distinction between wet and dry JJAs lies in the frequency of heavy precipitation events. During the wet JJAs, heavy precipitation events contribute to more than half of the JJA precipitation total.

scholarly journals Intensified Moisture Sources of Heavy Precipitation Events Contributed to Interannual Trend in Precipitation Over the Three-Rivers-Headwater Region in China

2021 ◽  
Vol 9 ◽  
Author(s):  
Ruiyu Zhao ◽  
Bin Chen ◽  
Xiangde Xu
Keyword(s):  
Water Vapor ◽  
Heavy Precipitation ◽  
Water Vapor Transport ◽  
Boreal Summer ◽  
Precipitation Trend ◽  
Moisture Source ◽  
Moisture Sources ◽  
Increasing Trend ◽  
Three Rivers ◽  
Precipitation Events

Evidence has indicated an overall wetting trend over the Three-Rivers Headwater Region (TRHR) in the recent decades, whereas the possible mechanisms for this change remain unclear. Detecting the main moisture source regions of the water vapor and its increasing trend over this region could help understand the long-term precipitation change. Based on the gauge-based precipitation observation analysis, we find that the heavy precipitation events act as the main contributor to the interannual increasing trend of summer precipitation over the TRHR. A Lagrangian moisture tracking methodology is then utilized to identify the main moisture source of water vapor over the target region for the boreal summer period of 1980–2017, with focus particularly on exploring its change associated with the interannual trend of precipitation. On an average, the moisture sources for the target regions cover vast regions, including the west and northwest of the Tibetan Plateau by the westerlies, the southwest by the Indian summer monsoon, and the adjacent regions associated with the local recycling. However, the increased interannual precipitation trend over the TRHR could be largely attributed to the enhanced moisture sources from the neighboring northeastern areas of the targeted region, particularly associated with the heavy precipitation events. The increased water vapor transport from the neighboring areas of the TRHR potentially related to the enhanced local hydrological recycling over these regions plays a first leading role in the recent precipitation increase over the TRHR.

scholarly journals Impacts of Convective Activity over the Tibetan Plateau on Plateau Vortex, Southwest Vortex, and Downstream Precipitation

2019 ◽  
Vol 76 (12) ◽  
pp. 3803-3830 ◽  
Author(s):  
Shen-Ming Fu ◽  
Zi Mai ◽  
Jian-Hua Sun ◽  
Wan-Li Li ◽  
Yang Ding ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Potential Vorticity ◽  
Small Proportion ◽  
Geopotential Height ◽  
Sichuan Basin ◽  
Heavy Precipitation ◽  
The Tibetan Plateau ◽  
Convective Activity ◽  
Southwest Vortex ◽  
The Sichuan Basin

Abstract In summer, convective activity over the Tibetan Plateau (TP) is vigorous, with some of it moving eastward and vacating the plateau [defined as the eastward-moving type (EMT)]. Although the EMT only accounts for a small proportion, it is closely related to heavy precipitation east of the TP. This study investigates EMT impacts based on a series of composite semi-idealized simulations and piecewise potential vorticity (PV) inversion. The main results are as follows. (i) An EMT begins to affect downstream precipitation before it vacates the TP. A weaker EMT tends to cause the main downstream rainband to reduce in intensity and move southward. (ii) The EMT contributes to the formation of an eastward-moving plateau vortex (PLV) by enhancing convergence-induced stretching. Over the TP, the PLV mainly enhances/maintains the EMT, whereas during the vacating stage, the PLV dissipates (since convergence decreases rapidly when sensible heating from the TP reduces), which substantially reduces the intensity of the EMT. (iii) After PLV dissipation, a southwest vortex (SWV) forms around the Sichuan basin mainly due to convergence-induced stretching, convection-related tilting, and background transport. Piecewise PV inversion indicates that an EMT can directly contribute to SWV formation via lowering geopotential height and enhancing cyclonic wind perturbations around the Sichuan basin (even before its vacating stage), while neither of them governs the SWV formation. Sensitivity runs show that an EMT is not necessary for SWV formation, but can modify the SWV formation time and location, as well as its displacement, which significantly affects downstream precipitation.

scholarly journals Moisture Sources of Torrential Rainfall Events in the Sichuan Basin of China during Summers of 2009–13

2015 ◽  
Vol 16 (4) ◽  
pp. 1906-1917 ◽  
Author(s):  
Yongjie Huang ◽  
Xiaopeng Cui
Keyword(s):  
Bay Of Bengal ◽  
Sichuan Basin ◽  
Dispersion Model ◽  
Source Region ◽  
Particle Dispersion ◽  
The Tibetan Plateau ◽  
Rainfall Events ◽  
Moisture Sources ◽  
Torrential Rainfall ◽  
The Sichuan Basin

Abstract Water vapor sources and transport paths associated with torrential rains are very important to research and forecasts. This study investigates the main moisture sources and transport paths related to torrential rainfall events in the Sichuan basin of China, which is located east of the Tibetan Plateau, using a Lagrangian flexible particle dispersion model (FLEXPART). Based on the analysis of the torrential rainfall distribution during 2009–13, four study areas are selected in the basin. Particles that have a great contribution to the torrential rainfall events within the four study areas are traced back for 10 days, and a quantitative analysis of the contributions from various moisture sources to the torrential rainfall events is also conducted. The results indicate that a large number of target particles start at the Arabian Sea and the Bay of Bengal, land on the Indo-China Peninsula, and finally reach the study areas. This is an important moisture transport path for the torrential rainfall events within the four study areas. Another important path is from the neighborhood of the Sichuan basin. The total moisture supplies from all examined moisture sources within the whole atmospheric layer account for more than 90% of precipitation within the study areas. There are two major moisture sources, the Sichuan basin and the Bay of Bengal, and the South China Sea could be another important moisture source region for the torrential rains in the northeastern Sichuan basin.

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