A seven-year climatology of the initiation, decay and morphology of severe convective storms during the warm season over North China

2021 ◽  
Author(s):  
Ruoyun Ma ◽  
Jianhua Sun ◽  
Xinlin Yang
Keyword(s):  
Nonlinear Systems ◽  
Short Duration ◽  
Heavy Rainfall ◽  
North China ◽  
Doppler Radar ◽  
Warm Season ◽  
High Wind ◽  
Convective Storms ◽  
Reflectivity Data ◽  
Convective Weather

AbstractThe present work established a 7-year climatology of the initiation, decay, and morphology of severe convective storms (SCSs) during the warm seasons (May–September) of 2011–2018 (except 2014) over North China. This was achieved by using severe weather reports, precipitation observations, and composite Doppler radar reflectivity data. A total of 371 SCSs were identified. SCSs primarily initiated around noon with the highest frequency over the high terrain of Mount Taihang, and they mostly decayed over the plains at night. The storm morphologies were classified into three types of cellular storms (individual cells, clusters of cells, and broken lines), six types of linear systems (convective lines with no stratiform, with trailing stratiform, leading stratiform, parallel stratiform, embedded lines, and bow echoes), and nonlinear systems. Three types of severe convective weather, namely, short-duration heavy rainfall, hail, and thunderstorm high winds associated with these morphologies were investigated. Nonlinear systems were the most frequent morphology, followed by clusters of cells. Convective lines with trailing stratiform were the most frequent linear morphology. A total of 1,429 morphology samples from the 371 SCSs were found to be responsible for 15,966 severe convective weather reports. Linear (nonlinear) systems produced the most short-duration heavy rainfall (hail and thunderstorm high wind) reports. Bow echos were most efficient in producing both short-duration heavy rainfall and thunderstorm high wind reports whereas broken lines had the highest efficiency for hail production. The results in the present study are helpful for local forecasters to better anticipate the storm types and associated hazardous weather.

Distribution and diurnal variation of warm-season short-duration heavy rainfall in relation to the MCSs in China

2013 ◽  
Vol 27 (6) ◽  
pp. 868-888 ◽  
Author(s):  
Jiong Chen ◽  
Yongguang Zheng ◽  
Xiaoling Zhang ◽  
Peijun Zhu
Keyword(s):  
Diurnal Variation ◽  
Short Duration ◽  
Heavy Rainfall ◽  
Warm Season

scholarly journals Comparison between GOES-12 Overshooting-Top Detections, WSR-88D Radar Reflectivity, and Severe Storm Reports

2012 ◽  
Vol 27 (3) ◽  
pp. 684-699 ◽  
Author(s):  
Richard Dworak ◽  
Kristopher Bedka ◽  
Jason Brunner ◽  
Wayne Feltz
Keyword(s):  
United States ◽  
Heavy Rainfall ◽  
Situational Awareness ◽  
Warm Season ◽  
Heavy Precipitation ◽  
Severe Weather ◽  
High Temporal Resolution ◽  
Eastern United States ◽  
Severe Storm ◽  
Convective Storms

Abstract Studies have found that convective storms with overshooting-top (OT) signatures in weather satellite imagery are often associated with hazardous weather, such as heavy rainfall, tornadoes, damaging winds, and large hail. An objective satellite-based OT detection product has been developed using 11-μm infrared window (IRW) channel brightness temperatures (BTs) for the upcoming R series of the Geostationary Operational Environmental Satellite (GOES-R) Advanced Baseline Imager. In this study, this method is applied to GOES-12 IRW data and the OT detections are compared with radar data, severe storm reports, and severe weather warnings over the eastern United States. The goals of this study are to 1) improve forecaster understanding of satellite OT signatures relative to commonly available radar products, 2) assess OT detection product accuracy, and 3) evaluate the utility of an OT detection product for diagnosing hazardous convective storms. The coevolution of radar-derived products and satellite OT signatures indicates that an OT often corresponds with the highest radar echo top and reflectivity maximum aloft. Validation of OT detections relative to composite reflectivity indicates an algorithm false-alarm ratio of 16%, with OTs within the coldest IRW BT range (<200 K) being the most accurate. A significant IRW BT minimum typically present with an OT is more often associated with heavy precipitation than a region with a spatially uniform BT. Severe weather was often associated with OT detections during the warm season (April–September) and over the southern United States. The severe weather to OT relationship increased by 15% when GOES operated in rapid-scan mode, showing the importance of high temporal resolution for observing and detecting rapidly evolving cloud-top features. Comparison of the earliest OT detection associated with a severe weather report showed that 75% of the cases occur before severe weather and that 42% of collocated severe weather reports had either an OT detected before a severe weather warning or no warning issued at all. The relationships between satellite OT signatures, severe weather, and heavy rainfall shown in this paper suggest that 1) when an OT is detected, the particular storm is likely producing heavy rainfall and/or possibly severe weather; 2) an objective OT detection product can be used to increase situational awareness and forecaster confidence that a given storm is severe; and 3) this product may be particularly useful in regions with insufficient radar coverage.

scholarly journals Assimilation of Doppler Radar Data and Its Impact on Prediction of a Heavy Meiyu Frontal Rainfall Event

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Hongli Li ◽  
Xiangde Xu ◽  
Yang Hu ◽  
Yanjiao Xiao ◽  
Zhibin Wang
Keyword(s):  
Heavy Rainfall ◽  
Doppler Radar ◽  
Radar Data ◽  
Correction Method ◽  
Rainfall Event ◽  
Radar Reflectivity ◽  
Local Analysis ◽  
Heavy Rainfall Event ◽  
Radar Observations ◽  
Reflectivity Data

Operational Doppler radar observations have potential advantages over other above-surface observations when it comes to assimilation for mesoscale model simulations with high spatial and temporal resolution. To improve the forecast of a heavy frontal rainfall event that occurred in the Yangtze-Huaihe River Basin from 4 July to 5 July 2014 in China, operational radar observations are assimilated by the Local Analysis and Prediction System (LAPS). Radar reflectivity data are used primarily in the LAPS cloud analysis procedure, which retrieves the number of hydrometeors and adjusts the moisture and cloud fields. Radial velocity data are analyzed through the LAPS wind analysis-based successive correction method. A new correction method is developed to correct three-dimensional radar reflectivity data based on hourly surface rain gauge observations. The performance of the correction method is demonstrated by assimilating radar reflectivity observations into LAPS. Experiments with different radar data assimilation are examined. Results show that the assimilation of radar data can effectively correct the background errors and improve the heavy rainfall forecast. The simulated intensity, pattern, and temporal evolution of the heavy rainfall event are better improved with radar reflectivity assimilation, especially when the correction method is implemented to correct radar observations.

Diverse synoptic weather patterns of warm-season heavy rainfall events in South Korea

2021 ◽  
Author(s):  
Chanil Park ◽  
Seok-Woo Son ◽  
Joowan Kim ◽  
Eun-Chul Chang ◽  
Jung-Hoon Kim ◽  
...  
Keyword(s):  
North Pacific ◽  
Moisture Transport ◽  
Heavy Rainfall ◽  
Eastern China ◽  
Warm Season ◽  
Sea Level Pressure ◽  
Rainfall Events ◽  
Weather Patterns ◽  
Synoptic Weather ◽  
Heavy Rainfall Events

AbstractThis study identifies diverse synoptic weather patterns of warm-season heavy rainfall events (HREs) in South Korea. The HREs not directly connected to tropical cyclones (TCs) (81.1%) are typically associated with a midlatitude cyclone from eastern China, the expanded North Pacific high and strong southwesterly moisture transport in between. They are frequent both in the first (early summer) and second rainy periods (late summer) with impacts on the south coast and west of the mountainous region. In contrast, the HREs resulting from TCs (18.9%) are caused by the synergetic interaction between the TC and meandering midlatitude flow, especially in the second rainy period. The strong south-southeasterly moisture transport makes the southern and eastern coastal regions prone to the TC-driven HREs. By applying a self-organizing map algorithm to the non-TC HREs, their surface weather patterns are further classified into six clusters. Clusters 1 and 3 exhibit frontal boundary between the low and high with differing relative strengths. Clusters 2 and 5 feature an extratropical cyclone migrating from eastern China under different background sea-level pressure patterns. Cluster 4 is characterized by the expanded North Pacific high with no organized negative sea-level pressure anomaly, and cluster 6 displays a development of a moisture pathway between the continental and oceanic highs. Each cluster exhibits a distinct spatio-temporal occurrence distribution. The result provides useful guidance for predicting the HREs by depicting important factors to be differently considered depending on their synoptic categorization.

The Bow and Arrow Mesoscale Convective Structure

2013 ◽  
Vol 141 (5) ◽  
pp. 1648-1672 ◽  
Author(s):  
Kelly M. Keene ◽  
Russ S. Schumacher
Keyword(s):  
Heavy Rainfall ◽  
Prediction Models ◽  
Weather Prediction ◽  
Warm Season ◽  
Severe Weather ◽  
Cold Pool ◽  
Horizontal Shear ◽  
Convective Systems ◽  
Wind Speeds ◽  
Bow And Arrow

Abstract The accurate prediction of warm-season convective systems and the heavy rainfall and severe weather associated with them remains a challenge for numerical weather prediction models. This study looks at a circumstance in which quasi-stationary convection forms perpendicular to, and above the cold-pool behind strong bow echoes. The authors refer to this phenomenon as a “bow and arrow” because on radar imagery the two convective lines resemble an archer’s bow and arrow. The “arrow” can produce heavy rainfall and severe weather, extending over hundreds of kilometers. These events are challenging to forecast because they require an accurate forecast of earlier convection and the effects of that convection on the environment. In this study, basic characteristics of 14 events are documented, and observations of 4 events are presented to identify common environmental conditions prior to the development of the back-building convection. Simulations of three cases using the Weather Research and Forecasting Model (WRF) are analyzed in an attempt to understand the mechanisms responsible for initiating and maintaining the convective line. In each case, strong southwesterly flow (inducing warm air advection and gradual isentropic lifting), in addition to directional and speed convergence into the convective arrow appear to contribute to initiation of convection. The linear orientation of the arrow may be associated with a combination of increased wind speeds and horizontal shear in the arrow region. When these ingredients are combined with thermodynamic instability, there appears to be a greater possibility of formation and maintenance of a convective arrow behind a bow echo.

Simulation of bromide and nitrate leaching under heavy rainfall and high-intensity irrigation rates in North China Plain

2010 ◽  
Vol 97 (10) ◽  
pp. 1646-1654 ◽  
Author(s):  
Huanyuan Wang ◽  
Xiaotang Ju ◽  
Yongping Wei ◽  
Baoguo Li ◽  
Lulu Zhao ◽  
...  
Keyword(s):  
Nitrate Leaching ◽  
High Intensity ◽  
Heavy Rainfall ◽  
North China Plain ◽  
North China

scholarly journals A Study of Two Propagating Heavy-Rainfall Episodes near Taiwan during SoWMEX/TiMREX IOP-8 in June 2008. Part II: Sensitivity Tests on the Roles of Synoptic Conditions and Topographic Effects

2014 ◽  
Vol 142 (8) ◽  
pp. 2644-2664 ◽  
Author(s):  
Chung-Chieh Wang ◽  
Jason Chieh-Sheng Hsu ◽  
George Tai-Jen Chen ◽  
Dong-In Lee
Keyword(s):  
Heavy Rainfall ◽  
Warm Season ◽  
Southwest Monsoon ◽  
First Episode ◽  
Topographic Effects ◽  
Terrain Effects ◽  
Sensitivity Tests ◽  
Synoptic Conditions ◽  
Synoptic Forcing ◽  
Central United States

Abstract This study is the second of a two-part series to investigate two rainfall episodes in the Hovmöller space near Taiwan during the eighth intensive observing period (IOP-8, 12–17 June 2008) of the Southwest Monsoon Experiment/Terrain-influenced Monsoon Rainfall Experiment (SoWMEX/TiMREX). The first episode moved eastward and the second westward, and both caused heavy rainfall in Taiwan. The goal of Part I was to better understand the mechanism and controlling factors for the organization and propagation of the episodes. Here in Part II, the detailed roles played by synoptic conditions and terrain effects are further examined. Three sensitivity tests (at 2.5-km grid spacing) are designed to include only the effects of synoptic evolution (SNP), and those from land–sea distribution–diurnal variations on top of a mean background with/without topography (DIU/DNT). As the benchmark, the control (CTL) experiment captures the 6-day event successfully and is validated in Part I. In SNP, the two episodes are reproduced with overall similarity to CTL and the observation, and this confirms that the general location/time of rainfall are mainly controlled by synoptic forcing in this case, in contrast to typical warm-season conditions in the central United States. Even so, diurnal effects can still exert discernible impacts and modulate local convective development in many instances, particularly an afternoon enhancement over terrain, and the averaged diurnal cycle in CTL over southeastern China resembles those in DIU/DNT rather than that in SNP (with no land). The steep topography of Taiwan is especially important for its rainfall distribution, including the heavy rainfall on 16 June through processes as postulated by Xu et al.

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