Numerical Simulation of a Heavy Rainstorm in Northeast China Caused by the Residual Vortex of Typhoon 1909 (Lekima)

From 14 to 17 August 2019, a heavy rainstorm occurred in Northeast China due to the combined influence of the residual vortex of typhoon 1909 (Lekima) and cold air intrusion. Based on the precipitation data of China Meteorological observation stations, surface and upper charts, HMW-8 satellite images, NCEP/NCAR 0.25° × 0.25° reanalysis data and WRF4.0 numerical prediction model are used to carry out numerical simulations. According to the weather situation and numerical simulation results, the cause of 1 h severe precipitation is thoroughly studied. Results show that: (1) According to the weather situation, the precipitation process can be divided into two stages. The first stage is from 1412 to 1612 August 2019, which is caused by the interaction between the residual vortex, the inverted trough of typhoon 1909 (Lekima) and the upper trough. The rain belt lies from northeast to southwest, and the rainfall center has typical meso-β-scale characteristics. At the second stage from 1612 to 1712 August 2019, the residual vortex of typhoon reaches Heilongjiang Province, at the same time, 500 hPa cold vortex falls to the south; (2) Based on the 1 h rainfall of automatic weather stations, it can be seen that there are three rainfall peaks from 00 UTC 14 to 12 UTC 17, which are 53.2 mm in the Middle East of Jilin Province, 38.2 mm in the south of 1610 Liaoning Province, and 21.3 mm in the east of 1707 Heilongjiang Province respectively. (3) Before the occurrence of 1 h heavy rainfall, the water vapor is concentrated in the middle and lower troposphere. The residual vortex trough of typhoon 1909 extends northward, converges with the southwest airflow at the edge of the subtropical high, and transports water vapor and energy to the northeast. The convective cloud clusters generated ahead of the trough move southeast, then merge into the mesoscale convective system in the inverted trough; (4) In the Bohai Bay and North Korea, there is a vortex-like zone composed of several convergence centers, and the convergence zone in typhoon-inverted trough meets with the trough in Central Jilin. There exist a rising area and a positive vorticity belt in the typhoon-inverted trough, and the center of heavy rain lies in front of the positive vorticity center. At the west of the inverted trough, there is a large center of positive vertical wind shear, and a small center in the east. The center of heavy rainfall is located on the line between the maximum and minimum centers, which is close to the right of the maximum center; (5) The high energy tongue is transported from the center of the typhoon to the northeast along the inverted trough of the typhoon, and the southwest airflow at the edge of the subtropical high. There is a zone titled downward from northwest to southeast that contains dry and cold air, where there is convective instability; (6) The strong precipitation area is located on the lee in the northwest of Changbai Mountain. There is a convergence area in the middle of the troposphere, and a strong divergence area in the upper troposphere, with remarkable topographic effect, and the west divergence column inclines on the east convergence column.

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Tectonic Evolution and Coal-Bearing Series Hosting Status Analysis on Coal Basins in Eastern Heilongjiang Province in China

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.734-737.448 ◽

2013 ◽

Vol 734-737 ◽

pp. 448-451 ◽

Cited By ~ 1

Author(s):

Ai Jun Guo ◽

Hao Xu ◽

Kang Liu

Keyword(s):

Coal Seam ◽

Tectonic Evolution ◽

Northeast China ◽

Heilongjiang Province ◽

Rift Basins ◽

The West ◽

Provenance Areas ◽

Tectonic Forces ◽

Status Analysis ◽

The Relationship

The eastern part of Heilongjiang province is an important energy base in northeast China, with more than fifty small and medium sized coal basins. The article analyzed the relationship between the basins characteristics and the coal-bearing series deposits in this area. In the early Cretaceous, all the eastern Heilongjiang province area was a large continental margin basin, with the main provenance area located in its west. This makes the coal accumulating effect at that time occurs mainly in the west of the near provenance areas, forming the main coal seam in this province. The second major coal accumulating, mainly in rift basins, happened in Paleocene. In late Cretaceous and Paleocene, the former coal accumulating basin was transformed and damaged because of tectonic forces, so that the current coal-bearing series distribution is characterized by isolated small and medium sized coal basins.

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Extreme Floods in the Eastern Part of Europe: Large-Scale Drivers and Associated Impacts

Water ◽

10.3390/w13081122 ◽

2021 ◽

Vol 13 (8) ◽

pp. 1122

Author(s):

Monica Ionita ◽

Viorica Nagavciuc

Keyword(s):

Water Vapor ◽

Heavy Rainfall ◽

Large Scale ◽

Vapor Transport ◽

Water Vapor Transport ◽

Flood Events ◽

Rainfall Events ◽

Catchment Areas ◽

Large Scale Atmospheric Circulation ◽

Heavy Rainfall Events

The role of the large-scale atmospheric circulation in producing heavy rainfall events and floods in the eastern part of Europe, with a special focus on the Siret and Prut catchment areas (Romania), is analyzed in this study. Moreover, a detailed analysis of the socio-economic impacts of the most extreme flood events (e.g., July 2008, June–July 2010, and June 2020) is given. Analysis of the largest flood events indicates that the flood peaks have been preceded up to 6 days in advance by intrusions of high Potential Vorticity (PV) anomalies toward the southeastern part of Europe, persistent cut-off lows over the analyzed region, and increased water vapor transport over the catchment areas of Siret and Prut Rivers. The vertically integrated water vapor transport prior to the flood peak exceeds 300 kg m−1 s−1, leading to heavy rainfall events. We also show that the implementation of the Flood Management Plan in Romania had positive results during the 2020 flood event compared with the other flood events, when the authorities took several precaution measurements that mitigated in a better way the socio-economic impact and risks of the flood event. The results presented in this study offer new insights regarding the importance of large-scale atmospheric circulation and water vapor transport as drivers of extreme flooding in the eastern part of Europe and could lead to a better flood forecast and flood risk management.

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Using reflection seismic method to estimate the fluid dynamics parameters related to wakes

10.5194/egusphere-egu21-9332 ◽

2021 ◽

Author(s):

Wenhao Fan ◽

Haibin Song ◽

Kun Zhang ◽

Yi Gong ◽

Shun Yang ◽

...

Keyword(s):

Potential Vorticity ◽

Negative Potential ◽

Distribution Area ◽

The West ◽

West Side ◽

Reflection Seismic ◽

Vorticity Distribution ◽

Positive Vorticity ◽

Coherent Vortices ◽

Survey Line

<p>In this study, when using reflection seismic data to study the wakes of the Batan Islands, a method for estimating the fluid dynamics parameters such as the relative vorticity (relative Rossby number) and the relative potential vorticity is proposed. Although the relative Rossby number estimation method proposed in this study cannot guarantee absolute accuracy in the calculation value, this method is more accurate in describing the positive and negative vorticity distribution for the wakes, and the resolution of the positive and negative vorticity distribution described by this method is higher than the result of the reanalysis data. For the wakes developed in the Batan Islands, the reflection events in the wake development area have the larger inclination than the reflection events in the western Pacific water distribution area. It is also found that the negative vorticity wakes are mainly distributed on the west side of the island/ridge, and the positive vorticity wakes are mainly distributed on the east side of the island/ridge. This is consistent with the understanding of previous wakes simulations. The strong vorticity values in the study area are mainly distributed at depths above 300m, and the maximum impact depth of wakes can reach 600m. At the downstream position of the wake on the survey line 7, it can be seen that the bottom boundary layer has separated, and there is the negative vorticity wakes on the west side intruding into the positive vorticity wakes on the east side , which is presumed to be caused by the disturbance of the small anticyclone existing near the Batan Islands. For the survey line 7, the negative potential vorticity is mainly distributed on the west side of the island/ridge, and the influence range can reach the sea depth of 600m. In the negative potential vorticity region, there is strong energy dissipation and vertical shear. In this study, we don&#8217;t find the existence of submesoscale coherent vortices on the survey line 7, but find the reflection structure similar to filaments on the seismic section. Combined with the analysis of the balanced Richardson number angle of survey line 7, we speculate that the wake in the negative potential vorticity distribution area has the characteristics of symmetrical instability, and the symmetrical instability may destroy the process of filaments forming submesoscale coherent vortices.</p>

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Cause Analysis on Eastward Movement of Southwest China Vortex and Its Induced Heavy Rainfall in South China

Advances in Meteorology ◽

10.1155/2015/481735 ◽

2015 ◽

Vol 2015 ◽

pp. 1-22 ◽

Cited By ~ 9

Author(s):

Yongren Chen ◽

Yueqing Li ◽

Tianliang Zhao

Keyword(s):

South China ◽

Heavy Rainfall ◽

Southwest China ◽

Dominant Role ◽

Vertical Wind Shear ◽

Heavy Rain ◽

Convective Systems ◽

Rainfall Occurrence ◽

Positive Vorticity ◽

Upper Level Jet

The movement of southwest China vortex (SWV) and its heavy rainfall process in South China had been investigated during June 11–14, 2008. The results show that under the steering of upper-level jet (ULJ) and mid-level westerly trough, SWV moved eastward from southern Sichuan Plateau, across eastern Yunnan-Guizhou Plateau to South China, forming an obvious heavy rain belt. SWV developed in the large storm-relative helicity (SRH) environment, as environmental wind field continuously transferred positive vorticity to it to support its development. The thermodynamic structures of distinctive warm (cold) advections in front (rear) of the SWV movement are also important factors for the SWV evolutions with a southwest low-level jet (LLJ) and vertical wind shear. SWV development was associated with the distributions of negative MPV1 (the barotropic item of moist potential vorticity) and positive MPV2 (the baroclinic item of it). The MPV1 and MPV2 played the dominant role in the formation and the evolution of SWV, respectively. The mesoscale convective systems (MCSs) frequently occurred and persisted in water vapor convergence areas causing the severe heavy rainfall. The areas of high moist helicity divergence and heavy rainfall are consistent, and the moist helicity divergence could be a good indicator for heavy rainfall occurrence.

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Assessment of Numerical Weather Prediction Model Reforecasts of the Occurrence, Intensity, and Location of Atmospheric Rivers along the West Coast of North America

Monthly Weather Review ◽

10.1175/mwr-d-18-0060.1 ◽

2018 ◽

Vol 146 (10) ◽

pp. 3343-3362 ◽

Cited By ~ 13

Author(s):

Kyle M. Nardi ◽

Elizabeth A. Barnes ◽

F. Martin Ralph

Keyword(s):

Water Vapor ◽

North America ◽

Weather Prediction ◽

Vapor Transport ◽

Water Vapor Transport ◽

Lead Times ◽

Model Errors ◽

The West ◽

Atmospheric Rivers ◽

Landfall Location

AbstractAtmospheric rivers (ARs)—narrow corridors of high atmospheric water vapor transport—occur globally and are associated with flooding and maintenance of the water supply. Therefore, it is important to improve forecasts of AR occurrence and characteristics. Although prior work has examined the skill of numerical weather prediction (NWP) models in forecasting atmospheric rivers, these studies only cover several years of reforecasts from a handful of models. Here, we expand this previous work and assess the performance of 10–30 years of wintertime (November–February) AR landfall reforecasts from the control runs of nine operational weather models, obtained from the International Subseasonal to Seasonal (S2S) Project database. Model errors along the west coast of North America at leads of 1–14 days are examined in terms of AR occurrence, intensity, and landfall location. Occurrence-based skill approaches that of climatology at 14 days, while models are, on average, more skillful at shorter leads in California, Oregon, and Washington compared to British Columbia and Alaska. We also find that the average magnitude of landfall integrated water vapor transport (IVT) error stays fairly constant across lead times, although overprediction of IVT is common at later lead times. Finally, we show that northward landfall location errors are favored in California, Oregon, and Washington, although southward errors occur more often than expected from climatology. These results highlight the need for model improvements, while helping to identify factors that cause model errors.

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