scholarly journals Precipitation Variations in the Flood Seasons of 1910–2019 in Hunan and Its Association With the PDO, AMO, and ENSO

2021 ◽  
Vol 9 ◽  
Author(s):  
Yuxing Zeng ◽  
Chao Huang ◽  
Yihao Tang ◽  
Jiadong Peng
Keyword(s):  
Water Vapor ◽  
El Niño ◽  
El Nino ◽  
Southern China ◽  
Vapor Transport ◽  
Hunan Province ◽  
Water Vapor Transport ◽  
Flood Season ◽  
La Nina ◽  
Interannual Scale

Floods in the middle reaches of the Yangtze River threaten thousands of million people, causing casualties and economic loss. Yet, the prediction of floods in this region is still challenging. To better understand the floods in this region, we investigate the interdecadal-interannual rainfall variation of the flood season (April–September) in Hunan province. The relationship between the rainfall and the Pacific decadal oscillation (PDO), Atlantic Multidecadal Oscillation (AMO), and El Niño-Southern Oscillation (ENSO) are also analyzed. The results show that the precipitation in the flood seasons shows an interdecadal oscillation with a period of about 20 years, which is caused by the joint effect of the PDO and AMO. When the PDO and AMO are in the same phase, the corresponding flood season is characterized by more precipitation, and conversely, it is less precipitation. Further analyses show that in the year after El Niño, when the PDO and AMO are both in the positive phase, it is favorable for the west Pacific subtropical high (WPSH) to be stronger and more southward than normal. Such circulation anomaly is conducive to the water vapor transport to the southern China, and as a result there is more precipitation in Hunan. When the PDO and AMO are both in the negative phase, the WPSH is weaker than normal, but the India-Burma trough is obviously stronger, which is also favorable for the southwesterly water vapor transport to the southern China. However, in the next year of the La Niña year, regardless of the phase combination of the PDO and AMO, the southern coast of China are controlled by a negative geopotential height anomaly and the WPSH retreats to the sea, which is not conducive to the northward transport of water vapor, and the precipitation in Hunan is less than normal. But if only the cold SST background in the previous stage is considered (without reaching the standard of a La Niña event),is more precipitation in most of the Hunan Province. Therefore, at the interannual scale, the PDO and AMO also have a modulating effect on the precipitation signal. However, the interannual-scale ENSO signal has a greater influence on the precipitation in Hunan flood seasons. Our results will give implications for the predications of floods in Hunan.

scholarly journals Processes Governing Water Vapor Isotope Composition in the Indo-Pacific Region: Convection and Water Vapor Transport

2016 ◽  
Vol 29 (23) ◽  
pp. 8535-8546 ◽  
Author(s):  
Zhongyin Cai ◽  
Lide Tian
Keyword(s):  
Water Vapor ◽  
El Nino ◽  
Isotope Composition ◽  
Vapor Transport ◽  
Western Pacific ◽  
Water Vapor Transport ◽  
Pacific Region ◽  
Convective Activity ◽  
La Nina ◽  
The Western Pacific

Abstract In an effort to understand the mechanisms controlling water vapor isotope composition in the Indo-Pacific region, encompassing southeastern Asia, this study investigates the spatial and interannual patterns in summer [June–September (JJAS)] water vapor isotopologues retrieved from the Tropospheric Emission Spectrometer (TES), especially those patterns associated with convection and water vapor transport. Both precipitation and water vapor isotope values exhibit a V-shaped longitudinal pattern in their spatial variations, reflecting the gradual rainout and increase in convective intensity along water vapor transport routes. On the temporal scale, compared with the 2006–10 JJAS mean conditions, TES water vapor δD over the eastern Indian Ocean and southeastern Asia (R_W120; 10°S–30°N, 80°–120°E) is higher in the 2009 JJAS El Niño event when convective activity is reduced and lower in the 2010 JJAS La Niña event when convective activity is enhanced. This is consistent with the direct response of water vapor δD to deep convection. In contrast, TES water vapor δD over the western Pacific (R_WP; 10°S–30°N, 120°–140°E) is higher in the La Niña year than in the El Niño year, although convective activity in R_WP varies in the same manner as in R_W120. A comparison of water vapor δD values with convection and water vapor transport suggests that the westward transport of water vapor–isotopic anomalies and changes in the flux of water vapor transported from the central to the western Pacific lead to such an opposite response in the R_WP. These findings help interpret what causes the interannual variations recorded by Indo-Pacific water isotopologues.

scholarly journals A Diagnosis of Rainfall over South America during the 1997/98 El Niño Event. Part II: Roles of Water Vapor Transport and Stationary Waves

2002 ◽  
Vol 15 (5) ◽  
pp. 512-521 ◽  
Author(s):  
V. Brahmananda Rao ◽  
Srinivasa R. Chapa ◽  
J. P. R. Fernandez ◽  
Sergio H. Franchito
Keyword(s):  
Water Vapor ◽  
South America ◽  
El Niño ◽  
El Nino ◽  
Vapor Transport ◽  
Water Vapor Transport ◽  
Stationary Waves ◽  
El Niño Event

scholarly journals Water Vapor Transport and Moisture Budget over Eastern China: Remote Forcing from the Two Types of El Niño

2014 ◽  
Vol 27 (23) ◽  
pp. 8778-8792 ◽  
Author(s):  
Xiuzhen Li ◽  
Wen Zhou ◽  
Deliang Chen ◽  
Chongyin Li ◽  
Jie Song
Keyword(s):  
Water Vapor ◽  
El Niño ◽  
El Nino ◽  
Eastern China ◽  
Vapor Transport ◽  
Water Vapor Transport ◽  
Moisture Budget ◽  
Southern Boundary ◽  
Middle Troposphere ◽  
Moisture Deficit

Abstract The water vapor transport and moisture budget over eastern China remotely forced by the cold-tongue (CT) and warm-pool (WP) El Niño show striking differences throughout their lifetime. The water vapor transport response is weak in the developing summer but strong in the remaining phases of CT El Niño, whereas the opposite occurs during WP El Niño. WP El Niño causes a moisture deficit over the Yangtze River valley (YZ) in the developing summer and over southeastern China (SE) in the developing fall, whereas CT El Niño induces a moisture surplus first over SE during the developing fall with the influential area expanding in the decaying spring and shifting northward in the decaying summer. It is the divergence of meridional water vapor transport that dominates the total water vapor divergence anomaly, with the divergence of zonal transport showing an opposite pattern with smaller magnitude. Investigation of the vertical profile of moisture budget shows a great baroclinicity, with the strongest abnormal moisture budget occurring in different levels. The moisture transport via the southern boundary plays a crucial role in the regional moisture budget anomalies and is located near the surface over SE, in the lower troposphere over the YZ, and at the lower-middle troposphere over the eastern part of northern China. The enhanced moisture surplus near the surface forced by WP El Niño over SE in the mature winter and decaying spring is offset by a moisture deficit within the lower-middle troposphere due to a diverse response circulation at different vertical levels.

Spatial and temporal trends and variabilities of hailstones in the United States Northern Great Plains and their possible attributions

2021 ◽  
pp. 1-53
Author(s):  
Jong-Hoon Jeong ◽  
Jiwen Fan ◽  
Cameron R. Homeyer
Keyword(s):  
United States ◽  
Water Vapor ◽  
Interannual Variability ◽  
Great Plains ◽  
El Niño ◽  
El Nino ◽  
Vapor Transport ◽  
Water Vapor Transport ◽  
Northern Great Plains ◽  
Contributing Factors

AbstractFollowing on our study of hail for the Southern Great Plains (SGP), we investigated the spatial and temporal hail trends and variabilities for the Northern Great Plains (NGP) and the contributing factors for summers (June–August) focusing on the period of 2004–2016 using two independent hail datasets. Analysis for an extended period (1994–2016) with the hail reports was also conducted to more reliably investigate the contributing factors. Both severe hail (1″ < diameter ≤ 2″) and significant severe hail (SSH; diameter > 2″) were examined and similar results were obtained. The occurrence of hail over the NGP demonstrated a large interannual variability, with a positive slope overall. Spatially, the increase is mainly located in the western part of Nebraska, South Dakota, and North Dakota. We find the three major dynamical factors that most likely contribute to the hail interannual variability in the NGP are the El Niño-Southern Oscillation (ENSO), North Atlantic subtropical high (NASH), and low-level jet (LLJ). With a thermodynamical variable integrated water vapor transport that is strongly controlled by LLJ, the four factors can explain 78% of the interannual variability in the number of SSH reports. Hail occurrences in the La Niña years are higher than the El Niño years since the jet stream is stronger and NASH extends further into the southeastern United States, thereby strengthening the LLJ and in turn water vapor transport. Interestingly, the important factors impacting hail interannual variability over the NGP are quite different from those for the SGP, except for ENSO.

scholarly journals Atmospheric Rivers over the Northwestern Pacific: Climatology and Interannual Variability

2017 ◽  
Vol 30 (15) ◽  
pp. 5605-5619 ◽  
Author(s):  
Youichi Kamae ◽  
Wei Mei ◽  
Shang-Ping Xie ◽  
Moeka Naoi ◽  
Hiroaki Ueda
Keyword(s):  
Water Vapor ◽  
Interannual Variability ◽  
El Niño ◽  
El Nino ◽  
Vapor Transport ◽  
Water Vapor Transport ◽  
Boreal Summer ◽  
Northwestern Pacific ◽  
Atmospheric Rivers ◽  
Low Level

Atmospheric rivers (ARs), conduits of intense water vapor transport in the midlatitudes, are critically important for water resources and heavy rainfall events over the west coast of North America, Europe, and Africa. ARs are also frequently observed over the northwestern Pacific (NWP) during boreal summer but have not been studied comprehensively. Here the climatology, seasonal variation, interannual variability, and predictability of NWP ARs (NWPARs) are examined by using a large ensemble, high-resolution atmospheric general circulation model (AGCM) simulation and a global atmospheric reanalysis. The AGCM captures general characteristics of climatology and variability compared to the reanalysis, suggesting a strong sea surface temperature (SST) effect on NWPARs. The summertime NWPAR occurrences are tightly related to El Niño–Southern Oscillation (ENSO) in the preceding winter through Indo–western Pacific Ocean capacitor (IPOC) effects. An enhanced East Asian summer monsoon and a low-level anticyclonic anomaly over the tropical western North Pacific in the post–El Niño summer reinforce low-level water vapor transport from the tropics with increased occurrence of NWPARs. The strong coupling with ENSO and IPOC indicates a high predictability of anomalous summertime NWPAR activity.

scholarly journals ENSO’s Modulation of Water Vapor Transport over the Pacific–North American Region

2015 ◽  
Vol 28 (9) ◽  
pp. 3846-3856 ◽  
Author(s):  
Hye-Mi Kim ◽  
Michael A. Alexander
Keyword(s):  
United States ◽  
El Niño ◽  
North Pacific ◽  
Moisture Transport ◽  
El Nino ◽  
Tropical Pacific ◽  
Vapor Transport ◽  
Water Vapor Transport ◽  
Southwestern United States ◽  
The Pacific

Abstract The vertically integrated water vapor transport (IVT) over the Pacific–North American sector during three phases of ENSO in boreal winter (December–February) is investigated using IVT values calculated from the Climate Forecast System Reanalysis (CFSR) during 1979–2010. The shift of the location and sign of sea surface temperature (SST) anomalies in the tropical Pacific Ocean leads to different atmospheric responses and thereby changes the seasonal mean moisture transport into North America. During eastern Pacific El Niño (EPEN) events, large positive IVT anomalies extend northeastward from the subtropical Pacific into the northwestern United States following the anomalous cyclonic flow around a deeper Aleutian low, while a southward shift of the cyclonic circulation during central Pacific El Niño (CPEN) events induces the transport of moisture into the southwestern United States. In addition, moisture from the eastern tropical Pacific is transported from the deep tropical eastern Pacific into Mexico and the southwestern United States during CPEN. During La Niña (NINA), the seasonal mean IVT anomaly is opposite to that of two El Niño phases. Analyses of 6-hourly IVT anomalies indicate that there is strong moisture transport from the North Pacific into the northwestern and southwestern United States during EPEN and CPEN, respectively. The IVT is maximized on the southeastern side of a low located over the eastern North Pacific, where the low is weaker but located farther south and closer to shore during CPEN than during EPEN. Moisture enters the southwestern United States from the eastern tropical Pacific during NINA via anticyclonic circulation associated with a ridge over the southern United States.

Role of intraseasonal oscillation in asymmetric impacts of El Niño and La Niña on the rainfall over southern China in boreal winter

2014 ◽  
Vol 45 (3-4) ◽  
pp. 559-567 ◽  
Author(s):  
Renhe Zhang ◽  
Tianran Li ◽  
Min Wen ◽  
Liangke Liu
Keyword(s):  
El Niño ◽  
El Nino ◽  
Southern China ◽  
Intraseasonal Oscillation ◽  
La Niña ◽  
Boreal Winter ◽  
La Nina

scholarly journals The Effects of El Niño-South Oscillation on the Winter Haze Pollution of China

2017 ◽  
Author(s):  
Shuyun Zhao ◽  
Hua Zhang ◽  
Bing Xie
Keyword(s):  
East Asia ◽  
El Niño ◽  
El Nino ◽  
Southern China ◽  
Eastern China ◽  
La Niña ◽  
Anthropogenic Aerosols ◽  
La Nina ◽  
Haze Pollution ◽  
Haze Days

Abstract. It is reported in previous studies that El Niño-South Oscillation (ENSO) influences not only the summer monsoon, but also the winter monsoon over East Asia. This contains some clues that ENSO may affect the winter haze pollution of China, which has become a serious problem in recent decades, through influencing the winter climate of East Asia. In this work, we explore the effects of ENSO on the winter (from December to February) haze pollution of China statistically and numerically. Statistical results reveal that the haze days of southern China tend to be less (more) than normal in El Niño (La Niña) winter; whereas the winter haze days of northern and eastern China have no significant relationship with ENSO. Results from numerical simulations show that under the emission level of aerosols for the year 2010, the winter-average atmospheric contents of anthropogenic aerosols over southern China are generally more (less) than normal in El Niño (La Niña) winter. It is because that the transports of aerosols from South and Southeast Asia to southern China are enhanced (weakened), which mask the better (worse) scavenging conditions for aerosols in El Niño (La Niña) winter. The probability density function (PDF) of the simulated daily surface concentrations of aerosols over southern China indicates that the region tends to have less clean and moderate (heavy) haze days, but more heavy (moderate) haze days in El Niño (La Niña) winter.

scholarly journals An Analysis of the Large-Scale Climate Anomalies Associated with the Snowstorms Affecting China in January 2008

2009 ◽  
Vol 137 (3) ◽  
pp. 1111-1131 ◽  
Author(s):  
Min Wen ◽  
Song Yang ◽  
Arun Kumar ◽  
Peiqun Zhang
Keyword(s):  
Water Vapor ◽  
Large Scale ◽  
Southern China ◽  
La Niña ◽  
Water Vapor Transport ◽  
The Arctic ◽  
Climate Anomalies ◽  
La Nina ◽  
Western Asia ◽  
The Arctic Oscillation

Abstract Extraordinarily frequent and long-lasting snowstorms affected China in January 2008, causing above-normal precipitation, below-normal temperature, and severe icing conditions over central–southern China. These snowstorms were closely linked to the change in the Middle East jet stream (MEJS), which intensified and shifted southeastward. The change in MEJS was accompanied by southeastward shifts of the ridge and the trough over Europe and western Asia. The intensified MEJS also strengthened the trough embedded in the southern branch of the subtropical westerlies over the southern Tibetan Plateau, enhancing the water vapor transport from western Asia and the Bay of Bengal to China. In the meantime, the subtropical western Pacific high (SWPH) was stronger and its ridgeline was farther north than normal. The anomalous high slowed down the eastward propagation of weather systems to the Pacific and favored convergence of water vapor over central–southern China. The MEJS is usually strong when the Arctic Oscillation (AO) is positive and the SWPH is farther north than normal in La Niña winters. Compared to the SWPH and the Niño-3.4 sea surface temperature (SST), the MEJS and the AO exert stronger influences on the temperature and the precipitation over central–southern China, despite the fact that these possible impacting factors are not completely independent from each other. Although the La Niña event might contribute to the climate anomalies through its relation with the SWPH in January 2008, an analysis of historical events indicates that La Niña conditions alone can hardly cause severe and persistent snow conditions over central–southern China. In addition, compared to the Niño-3.4 SST and the SWPH, the conditions of December MEJS and AO exhibit stronger precursory signals of the variability of January temperature over central–southern China.

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