Topographic effects on spatiotemporal variations of short-duration rainfall events in warm season of central North China

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.

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Changes in Duration-Related Characteristics of Late-Summer Precipitation over Eastern China in the Past 40 Years

Journal of Climate ◽

10.1175/jcli-d-11-00009.1 ◽

2011 ◽

Vol 24 (21) ◽

pp. 5683-5690 ◽

Cited By ~ 30

Author(s):

Jian Li ◽

Rucong Yu ◽

Weihua Yuan ◽

Haoming Chen

Keyword(s):

Short Duration ◽

North China ◽

Eastern China ◽

Summer Precipitation ◽

Late Summer ◽

Early Morning ◽

Rainfall Amount ◽

Rainfall Events ◽

Late Afternoon ◽

Long Duration

Abstract Duration is a key feature of rainfall events that is closely related to rainfall mechanisms and influences. This study analyzes the decadal change in the duration-related characteristics of late-summer (July–August) precipitation over eastern China during 1966–2005. Accompanying the southern-flooding and northern-drought (SFND) pattern of rainfall amount over the eastern China in recent decades, the duration-related rainfall structure also experienced significant changes. In North China, the frequency of short duration rainfall events decreased and their intensity increased. The decadal decreases of rainfall amount over North China are largely contributed by long duration rainfall events, especially those occurring between midnight and morning. In the mid-to-lower reaches of the Yangtze River valley, both the frequency and amount of long duration precipitation have significantly increased. The mean and maximum duration time of late-summer precipitation has increased 0.85 and 7.61 h, respectively. Considerable increases of rainfall amount of two kinds of precipitation, the short and medium duration rainfall events in the late afternoon and the long duration rainfall events in the early morning, contribute to the “southern-flooding.” Despite the differences between the northern and southern region, there is a common feature of their decadal precipitation changes that the intensity of short duration rainfall in the late afternoon has shown an increasing trend.

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

Monthly Weather Review ◽

10.1175/mwr-d-20-0388.1 ◽

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.

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The Use of Moist Potential Vorticity Vector as Diagnostic Variable of Rainfall Events in Tanzania

Applied Physics Research ◽

10.5539/apr.v9n5p1 ◽

2017 ◽

Vol 9 (5) ◽

pp. 1

Author(s):

Philbert Modest Luhunga ◽

Agnes Kijazi ◽

Ladislaus Chang a ◽

Chuki A Sangalugembe ◽

Doreen Mwara Anande ◽

...

Keyword(s):

Potential Vorticity ◽

Wrf Model ◽

Lower Troposphere ◽

Topographic Effects ◽

New Paradigm ◽

Rainfall Events ◽

North Eastern ◽

Vorticity Vector ◽

Moist Potential Vorticity ◽

Thermodynamic Variables

The work of this paper is a first step of the new paradigm, to use the Moist Potential Vorticity Vector (MPVV) as a diagnostic variable of rainfall events in Tanzania. The paper aims at computing and assessing the usefulness of MPVV in the diagnosis of rainfall events that occurred on 08th and 09th May 2017 over different regions in Tanzania. The relative contributions of horizontal, vertical components and the magnitude of MPVV on diagnosis of rainfall events are assessed. Hourly dynamic and thermodynamic variables of wind speed, temperature, atmospheric pressure and relative humidity from the numerical output generated by the Weather Research and Forecasting (WRF) Model, running at Tanzania Meteorological Agency (TMA) are used in computation of MPVV. The computed MPVV is then compared with WRF model forecasts and observed rainfall. It is found that in most parts of the country, particularly over coastal areas and North-Eastern Highlands, MPVV exhibited positive values in the lower troposphere (925hPa) and (850hPa) indicating local instability possibly associated with topographic effects, and continent/ocean contrast. MPVV is mostly positive with slightly negative values indicating instabilities (due to possible convective instability). Moreover, MPVV provides remarkably accurate tracking of the locations received rainfall, suggesting its potential use as a dynamic diagnostic variable of rainfall events in Tanzania.

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Spatiotemporal Variations Dictate Stable and Resilient Microbiome Interactions in the Chesapeake Bay

10.21203/rs.3.rs-117419/v1 ◽

2020 ◽

Author(s):

Hualong Wang ◽

Feng Chen ◽

Chuanlun Zhang ◽

Min Wang ◽

Jinjun Kan

Keyword(s):

Chesapeake Bay ◽

Structural Equation ◽

Regression Tree ◽

Warm Season ◽

Temporal Variations ◽

Microbial Interactions ◽

Equation Modeling ◽

Spatiotemporal Variations ◽

Particulate Carbon ◽

Estuarine Ecosystem

Abstract Background: Annually reoccurring microbial populations with strong spatial and temporal variations have been identified in estuarine environments, especially in those with long residence time such as the Chesapeake Bay (CB). However, it is unclear how microbial taxa interact with each other (e.g., mutualistic and competitive interactions) and how these interactions respond to their surrounding environments. Specifically, there is a lack of understanding of how these interactions influence microbiome population dynamics, and its adaptability and resilience to estuarine gradients. Results: Here, we constructed co-occurrence networks on prokaryotic microbial communities in the Bay, which included seasonal samples from seven spatial stations along the salinity gradients for three consecutive years. Our results showed that spatiotemporal variations of planktonic microbiomes promoted differentiations of the characteristics and stability of prokaryotic microbial networks in the CB estuary. Prokaryotic microbial networks are more stable seasonally than spatially, and microbes were more strongly connected during warm season compared to the associations during cold season. In addition, microbial interactions were more stable in the lower Bay (ocean side) than those in the upper Bay (freshwater side). Interestingly, compared to the abundant groups, the rare taxa such as SAR116 clade, SAR11 clade III, and OM182 clade contributed greatly to the stability and resilience of prokaryotic microbial interactions in the Bay. Modularity and cluster structures of microbial networks varied spatiotemporally, which provided valuable insights into the ‘small world’ (a group of more interconnected species), network stability, and habitat partitioning/preferences. Multivariate regression tree (MRT) analysis and Piecewise structural equation modeling (SEM) indicated that temperature, salinity and total suspended substances directly or indirectly (through nutrient availability, particulate carbon and Chl a) affected the distribution and associations of microbial groups, such as Actinobacteria, Bacteroidetes, Cyanobacteria, Planctomycetes, Proteobacteria, and Verrucomicrobia.Conclusion: Our results shed light on how spatiotemporal variations alter the nature and stability of prokaryotic microbial networks in the estuarine ecosystem, as well as the ability of planktonic microbiomes and their interactions to resist future disturbances.

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Analysing changes in short-duration extreme rainfall events

Proceedings of the Institution of Civil Engineers - Water Management ◽

10.1680/jwama.14.00040 ◽

2016 ◽

Vol 169 (5) ◽

pp. 201-211 ◽

Cited By ~ 1

Author(s):

Geoff J. C. Darch ◽

Robert T. McSweeney ◽

Christopher G. Kilsby ◽

Phillip D. Jones ◽

Timothy J. Osborn ◽

...

Keyword(s):

Short Duration ◽

Extreme Rainfall ◽

Extreme Rainfall Events ◽

Rainfall Events

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Warm season nocturnal rainfall over the eastern periphery of the Tibetan Plateau and its relationship with rainfall events in adjacent regions

International Journal of Climatology ◽

10.1002/joc.5696 ◽

2018 ◽

Vol 38 (13) ◽

pp. 4786-4801 ◽

Cited By ~ 1

Author(s):

Haoming Chen ◽

Jian Li ◽

Rucong Yu

Keyword(s):

Tibetan Plateau ◽

Warm Season ◽

The Tibetan Plateau ◽

Rainfall Events ◽

Eastern Periphery

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Spatial Heterogeneity Analysis of Short-Duration Extreme Rainfall Events in Megacities in China

Water ◽

10.3390/w12123364 ◽

2020 ◽

Vol 12 (12) ◽

pp. 3364 ◽

Cited By ~ 1

Author(s):

Qi Zhuang ◽

Shuguang Liu ◽

Zhengzheng Zhou

Keyword(s):

Spatial Heterogeneity ◽

Short Duration ◽

Urban Areas ◽

Spatial Association ◽

Extreme Rainfall ◽

Flood Frequency ◽

Flood Frequency Analysis ◽

Extreme Rainfall Events ◽

Rainfall Events ◽

Design Storm

Given the fact that researchers require more specific spatial rainfall information for storm flood calculation, hydrological risk assessment, and water budget estimates, there is a growing need to analyze the spatial heterogeneity of rainfall accurately. This paper provides insight into rainfall spatial heterogeneity in urban areas based on statistical analysis methods. An ensemble of short-duration (3-h) extreme rainfall events for four megacities in China are extracted from a high-resolution gridded rainfall dataset (resolution of 30 min in time, 0.1° × 0.1° in space). Under the heterogeneity framework using Moran’s I, LISA (Local Indicators of Spatial Association), and semi-variance, the multi-scale spatial variability of extreme rainfall is identified and assessed in Shanghai (SH), Beijing (BJ), Guangzhou (GZ), and Shenzhen (SZ). The results show that there is a pronounced spatial heterogeneity of short-duration extreme rainfall in the four cities. Heterogeneous characteristics of rainfall within location, range, and directions are closely linked to the different urban growth in four cities. The results also suggest that the spatial distribution of rainfall cannot be neglected in the design storm in urban areas. This paper constitutes a useful contribution to quantifying the degree of spatial heterogeneity and supports an improved understanding of rainfall/flood frequency analysis in megacities.

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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

Monthly Weather Review ◽

10.1175/mwr-d-13-00330.1 ◽

2014 ◽

Vol 142 (8) ◽

pp. 2644-2664 ◽

Cited By ~ 13

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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