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 Water vapor isotopes indicating rapid shift among multiple moisture sources for the 2018–2019 winter extreme precipitation events in southeastern China

2022 ◽  
Vol 26 (1) ◽  
pp. 117-127
Author(s):  
Tao Xu ◽  
Hongxi Pang ◽  
Zhaojun Zhan ◽  
Wangbin Zhang ◽  
Huiwen Guo ◽  
...  
Keyword(s):  
Water Vapor ◽  
South China ◽  
Extreme Precipitation ◽  
Southeastern China ◽  
China Sea ◽  
Moisture Source ◽  
Moisture Sources ◽  
Source Regions ◽  
Extreme Precipitation Events ◽  
Precipitation Events

Abstract. In the East Asian monsoon region, winter extreme precipitation events occasionally occur and bring great social and economic losses. From December 2018 to February 2019, southeastern China experienced a record-breaking number of extreme precipitation events. In this study, we analyzed the variation in water vapor isotopes and their controlling factors during the extreme precipitation events in Nanjing, southeastern China. The results show that the variations in water vapor isotopes are closely linked to the change in moisture sources. Using a water vapor d-excess-weighted trajectory model, we identified the following five most important moisture source regions: South China, the East China Sea, the South China Sea, the Bay of Bengal, and continental regions (northwestern China and Mongolia). Moreover, the variations in water vapor d excess during a precipitation event reflect rapid shifts in the moisture source regions. These results indicate that rapid shifts among multiple moisture sources are important conditions for sustaining wintertime extreme precipitation events over extended periods.

scholarly journals Water vapor isotopes indicating rapid shift among multiple moisture sources for the 2018/2019 winter extreme precipitation events in Southeast China

2021 ◽  
Author(s):  
Tao Xu ◽  
Hongxi Pang ◽  
Zhaojun Zhan ◽  
Wangbin Zhang ◽  
Huiwen Guo ◽  
...  
Keyword(s):  
Water Vapor ◽  
South China ◽  
Extreme Precipitation ◽  
Southeast China ◽  
China Sea ◽  
Moisture Source ◽  
Moisture Sources ◽  
Source Regions ◽  
Extreme Precipitation Events ◽  
Precipitation Events

Abstract. In the East Asian monsoon region, winter extreme precipitation events occasionally occur and bring great social and economic losses. From December 2018 to February 2019, Southeast China experienced a record-breaking number of extreme precipitation events. In this study, we analyzed the variation of water vapor isotopes and their controlling factors during the extreme precipitation events in Nanjing, Southeast China. The results show that the variations of water vapor isotopes are closely linked to the change of moisture sources. Using a water vapor d-excess weighted trajectory model, we identified five most important moisture source regions: South China, East China Sea, South China Sea, Bay of Bengal, and Continental regions (Northwest China and Mongolia). Moreover, the variations of water vapor d-excess during a precipitation event reflect rapid shifts of moisture source regions. These results indicate that rapid shifts among multiple moisture sources are important conditions for sustaining wintertime extreme precipitation events over extended periods.

scholarly journals Tracking an Atmospheric River in a Warmer Climate: from Water Vapor to Economic Impacts

2017 ◽  
Author(s):  
Francina Dominguez ◽  
Sandy Dall'erba ◽  
Shuyi Huang ◽  
Andre Avelino ◽  
Ali Mehran ◽  
...  
Keyword(s):  
Water Vapor ◽  
Economic Impacts ◽  
Heavy Precipitation ◽  
Integrated Modeling ◽  
Vapor Transport ◽  
Water Vapor Transport ◽  
Economic Losses ◽  
Radiative Forcings ◽  
Hypothetical Scenario ◽  
Western Washington

Abstract. Atmospheric rivers (ARs) account for more than 75 % of heavy precipitation events and nearly all of the extreme flooding events along the Olympic Mountains and western Cascade mountains of western Washington state. In a warmer climate, ARs in this region are projected to become more frequent and intense, primarily due to increases in atmospheric water vapor. However, it is unclear how the changes in water vapor transport will affect regional flooding and associated economic impacts. In this work, we present an integrated modeling system to quantify the atmospheric-hydrologic-hydraulic and economic impacts of the December 2007 AR event that impacted the Chehalis river basin in western Washington. We use the modeling system to project impacts under a hypothetical scenario where the same December 2007 event occurs in a warmer climate. This method allows us to incorporate different types of uncertainty including: a) alternative future radiative forcings, b) different responses of the climate system to future radiative forcings and c) different responses of the surface hydrologic system. In the warming scenario, AR integrated vapor transport increases, however, these changes do not translate into generalized increases in precipitation throughout the basin. The changes in precipitation translate into spatially heterogeneous changes in sub-basin runoff and increased streamflow along the entire Chehalis main stem. Economic losses due to stock damages increased moderately, but losses in terms of business interruption were significant. Our integrated modeling tool provides communities in the Chehalis region with a range of possible future physical and economic impacts associated with AR flooding.

scholarly journals Moisture Pathways into the U.S. Intermountain West Associated with Heavy Winter Precipitation Events*

2015 ◽  
Vol 16 (3) ◽  
pp. 1184-1206 ◽  
Author(s):  
Michael A. Alexander ◽  
James D. Scott ◽  
Dustin Swales ◽  
Mimi Hughes ◽  
Kelly Mahoney ◽  
...  
Keyword(s):  
Sierra Nevada ◽  
Heavy Precipitation ◽  
Empirical Orthogonal Functions ◽  
Water Vapor Transport ◽  
Intermountain West ◽  
Orthogonal Functions ◽  
Back Trajectories ◽  
Synoptic Conditions ◽  
The U.S ◽  
Precipitation Events

Abstract Two methods were used to identify the paths of moisture transport that reach the U.S. Intermountain West (IMW) during heavy precipitation events in winter. In the first, the top 150 precipitation events at stations located within six regions in the IMW were identified, and then back trajectories were initiated at 6-h intervals on those days at the four Climate Forecast System Reanalysis grid points nearest the stations. The second method identified the leading patterns of integrated water vapor transport (IVT) using the three leading empirical orthogonal functions of IVT over land that were first normalized by the local standard deviation. The top 1% of the associated 6-hourly time series was used to construct composites of IVT, atmospheric circulation, and precipitation. The results from both methods indicate that moisture originating from the Pacific that leads to extreme precipitation in the IMW during winter takes distinct pathways and is influenced by gaps in the Cascades (Oregon–Washington), the Sierra Nevada (California), and Peninsular Ranges (from Southern California through Baja California). The moisture transported along these routes appears to be the primary source for heavy precipitation for the mountain ranges in the IMW. The synoptic conditions associated with the dominant IVT patterns include a trough–ridge couplet at 500 hPa, with the trough located northwest of the ridge where the associated circulation funnels moisture from the west-southwest through the mountain gaps and into the IMW.

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 Horizontal water vapor transport in the lower stratosphere from subtropics to high latitudes during boreal summer

2013 ◽  
Vol 118 (14) ◽  
pp. 8111-8127 ◽  
Author(s):  
F. Ploeger ◽  
G. Günther ◽  
P. Konopka ◽  
S. Fueglistaler ◽  
R. Müller ◽  
...  
Keyword(s):  
Water Vapor ◽  
Lower Stratosphere ◽  
Vapor Transport ◽  
Water Vapor Transport ◽  
Boreal Summer ◽  
High Latitudes

scholarly journals Recent Changes in the Moisture Source of Precipitation over the Tibetan Plateau

2017 ◽  
Vol 30 (5) ◽  
pp. 1807-1819 ◽  
Author(s):  
Chi Zhang ◽  
Qiuhong Tang ◽  
Deliang Chen
Keyword(s):  
Tibetan Plateau ◽  
Land Surface ◽  
Hydrological Cycle ◽  
Land Surface Model ◽  
Water Vapor Transport ◽  
Surface Model ◽  
The Tibetan Plateau ◽  
Precipitation Trend ◽  
Moisture Source ◽  
Moisture Supply

Abstract Evidence has suggested a wetting trend over part of the Tibetan Plateau (TP) in recent decades, although there are large uncertainties in this trend due to sparse observations. Examining the change in the moisture source for precipitation over a region in the TP with the most obvious increasing precipitation trend may help understand the precipitation change. This study applied the modified Water Accounting Model with two atmospheric reanalyses, ground-observed precipitation, and evaporation from a land surface model to investigate the change in moisture source of the precipitation over the targeted region. The study estimated that on average more than 69% and more than 21% of the moisture supply to precipitation over the targeted region came from land and ocean, respectively. The moisture transports from the west of the TP by the westerlies and from the southwest by the Indian summer monsoon likely contributed the most to precipitation over the targeted region. The moisture from inside the region may have contributed about 18% of the total precipitation. Most of the increased moisture supply to the precipitation during 1979–2013 was attributed to the enhanced influx from the southwest and the local moisture supply. The precipitation recycling ratio over the targeted region increased significantly, suggesting an intensified hydrological cycle. Further analysis at monthly scale and with wet–dry-year composites indicates that the increased moisture contribution was mainly from the southwest and the targeted region during May and September. The enhanced water vapor transport from the Indian Ocean during July and September and the intensified local hydrological recycling seem to be the primary reasons behind the recent precipitation increase over the targeted region.

scholarly journals Comparison of Eulerian and Lagrangian moisture source diagnostics – the flood event in eastern Europe in May 2010

2013 ◽  
Vol 13 (11) ◽  
pp. 29333-29373 ◽  
Author(s):  
A. Winschall ◽  
S. Pfahl ◽  
H. Sodemann ◽  
H. Wernli
Keyword(s):  
Eastern Europe ◽  
Land Surface ◽  
Heavy Precipitation ◽  
Precipitation Event ◽  
Eulerian Model ◽  
Heavy Precipitation Event ◽  
Moisture Source ◽  
Moisture Sources ◽  
Source Regions ◽  
The Mediterranean

Abstract. Moisture convergence from different sources is an important prerequisite for a heavy precipitation event. The contributions from different source regions can, however, hardly be quantified from observations, and their assessment based on model results is complex. Two conceptually different numerical methods are widely used for the quantification of moisture sources: Lagrangian approaches based on the analysis of humidity variations along backward trajectories and Eulerian methods based on the implementation of moisture tracers into a numerical model. In this study the moisture sources for a high-impact heavy precipitation event that affected eastern Europe in May 2010 are studied with both Eulerian and Lagrangian moisture source diagnostics. The precipitation event was connected to a cyclone that developed over northern Africa, moved over the Mediterranean towards eastern Europe and induced transport of moist air towards the Carpathian mountains. Heavy precipitation and major flooding occurred in Poland, the Czech Republic and Slovakia between 16 and 18 May 2010. The Lagrangian and Eulerian diagnostics consistently indicate a~wide spatial and temporal range of moisture sources contributing to the event. The most important source is local evapotranspiration from the European land surface, followed by moisture from the North Atlantic. Further relevant contributions come from tropical Western Africa (10–20° N). Contrary to expectations, the Mediterranean Sea contributes only about 10% to the precipitation event. A detailed analysis of exemplary trajectories corroborates the general consistency of the two approaches, and underlines their complementarity. The Lagrangian method allows for mapping out moisture source regions with computational efficiency, whereas the more elaborate Eulerian model requires predefined moisture sources, but includes also processes such as precipitation, evaporation and turbulent mixing. However, in the Eulerian model, uncertainty concerning the relative importance of remote versus local moisture sources arises from different options to parameterise moisture tagging at the surface. Ultimately a more sophisticated parameterisation scheme will be required to reduce this uncertainty.

scholarly journals Climatology of Winter Orographic Precipitation over the Subtropical Central Andes and Associated Synoptic and Regional Characteristics

2011 ◽  
Vol 12 (4) ◽  
pp. 481-507 ◽  
Author(s):  
Maximiliano Viale ◽  
Mario N. Nuñez
Keyword(s):  
Water Vapor ◽  
Water Vapor Transport ◽  
Windward Side ◽  
Leeward Side ◽  
Orographic Precipitation ◽  
Mountain Range ◽  
The Andes ◽  
Precipitation Regimes ◽  
Fourth Quartile ◽  
Precipitation Events

Abstract Winter orographic precipitation over the Andes between 30° and 37°S is examined using precipitation gauges in the mountains and adjacent lowlands. Because of the limited number of precipitation gauges, this paper focuses on the large-scale variation in cross-barrier precipitation and does not take into account the fine ridge–valley scale. The maximum amount of precipitation was observed on the windward slope of the mountain range below the crest, which was twice that observed on the low-windward side between 32.5° and 34°S. Toward the east of the crest, precipitation amounts drop sharply, generating a strong cross-barrier gradient. The rain shadow effect is greater in the north (32°–34.5°S) than in the south (35°–36.5°S) of the low-lee side, which is probably due to more baroclinic activity in southernmost latitudes and a southward decrease in the height of the Andes enabling more spillover precipitation. The effect of the Andes on winter precipitation is so marked that it modifies the precipitation regimes in the adjacent windward and leeward lowlands north of 35°S. Based on the fact that ~75% of the wintertime precipitation accumulated in the fourth quartile, through four or five heavy events on average, the synoptic-scale patterns of the heavy (into fourth quartile) orographic precipitation events were identified. Heavy events are strongly related to strong water vapor transport from the Pacific Ocean in the pre-cold-front environment of extratropical cyclones, which would have the form of atmospheric rivers as depicted in the reanalysis and rawinsonde data. The composite fields revealed a marked difference between two subgroups of heavy precipitation events. The extreme (100th–95th percentiles) events are associated with deeper cyclones than those for intense (95th–75th percentiles) events. These deeper cyclones lead to much stronger plumes of water vapor content and cross-barrier moisture flux against the high Andes, resulting in heavier orographic precipitation for extreme events. In addition, regional airflow characteristics suggest that the low-level flow is typically blocked and diverted poleward in the form of an along-barrier jet. On the lee side, downslope flow dominates during heavy events, producing prominent rain shadow effects as denoted by the domain of downslope winds extending to low-leeward side (i.e., zonda wind).

scholarly journals An Analysis of Moisture Sources of Torrential Rainfall Events over Xinjiang, China

2019 ◽  
Vol 20 (10) ◽  
pp. 2109-2122 ◽  
Author(s):  
Yu-shu Zhou ◽  
Ze-ming Xie ◽  
Xin Liu
Keyword(s):  
Water Vapor ◽  
Central Asia ◽  
Dispersion Model ◽  
Source Area ◽  
Particle Dispersion ◽  
Rainfall Events ◽  
Moisture Source ◽  
Moisture Sources ◽  
North Asia ◽  
Torrential Rainfall

Abstract Water vapor is a primary rainfall source for the development of torrential rainfall events. By using a Lagrangian flexible particle dispersion model (FLEXPART), the water vapor transports associated with torrential rainfall over Xinjiang, China, during April–September of 2008–15 are examined in this study. The results show that water vapor related to torrential rainfall events is mostly transported by westerly winds. The moisture sources for the development of torrential rainfall over four areas (Altay, Ili Valley, Hami, and Aksu-Kashgar) are mainly from Xinjiang and central Asia. The north Asia area and the Mediterranean/Black/Caspian Sea region are also important contributors to moisture source over the Altay area. Over Ili Valley, both the central Asia area and Xinjiang contribute 40% of water vapor to rainfall sources. Over the Hami area, 70% of the moisture source is from the Xinjiang. Over the Aksu-Kashgar area, the central Asia region is the most important moisture source area.

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