An Integrated Damage, Visual, and Radar Analysis of the 2015 Foshan, Guangdong, EF3 Tornado in China Produced by the Landfalling Typhoon Mujigae (2015)

2017 ◽  
Vol 98 (12) ◽  
pp. 2619-2640 ◽  
Author(s):  
Lanqiang Bai ◽  
Zhiyong Meng ◽  
Ling Huang ◽  
Lijun Yan ◽  
Zhaohui Li ◽  
...  
Keyword(s):  
United States ◽  
Surface Wind ◽  
Surface Wind Speed ◽  
The United States ◽  
Case Review ◽  
Near Surface ◽  
Damage Indicators ◽  
Potential Applicability ◽  
Landfalling Typhoon ◽  
Tornado Damage

Abstract This work presents an integrated damage, visual, and radar analysis of a tropical cyclone (TC) tornado that has not been documented as detailed as midlatitude tornadoes. On 4 October 2015, an enhanced Fujita 3 (EF3) tornado spawned into Typhoon Mujigae and hit Foshan, Guangdong Province, China. This tornado was generated in a minisupercell ∼350 km northeast of the TC center and lasted about 32 minutes, leaving a southeast-to-northwest damage swath 30.85 km long and 20–570 m wide. Near-surface wind patterns and the size of the tornado, juxtaposition of the condensation funnel with the damage swath and radar signatures, and consistency between near-surface wind speed estimated from visual observations and that estimated using EF scale were revealed based on ground and aerial surveys, radar and surface observations, photographs, and tornado videos. Tornado videos showed two occurrences of vertical subvortices followed by the formation of a horizontal vortex. Some features of the tornado, the parent supercell and mesocyclone, and the convective environment were compared to their U.S. counterparts. This work provides a case review of a tornado with the most comprehensive information ever in China. Damage indicators used to estimate the tornado intensity in this Chinese case were compared with those in the United States, demonstrating the potential applicability of the EF scale in tornado damage surveys outside the United States.

scholarly journals Tornado Damage Rating Probabilities Derived from WSR-88D Data

2017 ◽  
Vol 32 (4) ◽  
pp. 1509-1528 ◽  
Author(s):  
Richard L. Thompson ◽  
Bryan T. Smith ◽  
Jeremy S. Grams ◽  
Andrew R. Dean ◽  
Joseph C. Picca ◽  
...  
Keyword(s):  
United States ◽  
Great Plains ◽  
Probability Distributions ◽  
Rotational Velocity ◽  
The United States ◽  
Low Level ◽  
Convective Systems ◽  
Severe Thunderstorms ◽  
Damage Indicators ◽  
Tornado Damage

Abstract Previous work with observations from the NEXRAD (WSR-88D) network in the United States has shown that the probability of damage from a tornado, as represented by EF-scale ratings, increases as low-level rotational velocity increases. This work expands on previous studies by including reported tornadoes from 2014 to 2015, as well as a robust sample of nontornadic severe thunderstorms [≥1-in.- (2.54 cm) diameter hail, thunderstorm wind gusts ≥ 50 kt (25 m s−1), or reported wind damage] with low-level cyclonic rotation. The addition of the nontornadic sample allows the computation of tornado damage rating probabilities across a spectrum of organized severe thunderstorms represented by right-moving supercells and quasi-linear convective systems. Dual-polarization variables are used to ensure proper use of velocity data in the identification of tornadic and nontornadic cases. Tornado damage rating probabilities increase as low-level rotational velocity Vrot increases and circulation diameter decreases. The influence of height above radar level (or range from radar) is less obvious, with a muted tendency for tornado damage rating probabilities to increase as rotation (of the same Vrot magnitude) is observed closer to the ground. Consistent with previous work on gate-to-gate shear signatures such as the tornadic vortex signature, easily identifiable rotation poses a greater tornado risk compared to more nebulous areas of cyclonic azimuthal shear. Additionally, tornado probability distributions vary substantially (for similar sample sizes) when comparing the southeast United States, which has a high density of damage indicators, to the Great Plains, where damage indicators are more sparse.

scholarly journals Homogenization and Trend Analysis of Canadian Near-Surface Wind Speeds

2010 ◽  
Vol 23 (5) ◽  
pp. 1209-1225 ◽  
Author(s):  
Hui Wan ◽  
Xiaolan L. Wang ◽  
Val R. Swail
Keyword(s):  
Wind Speed ◽  
Trend Analysis ◽  
Surface Wind ◽  
Surface Wind Speed ◽  
The United States ◽  
Homogeneity Test ◽  
Near Surface ◽  
Wind Speeds ◽  
Long Term Trends

Abstract Near-surface wind speeds recorded at 117 stations in Canada for the period from 1953 to 2006 were analyzed in this study. First, metadata and a logarithmic wind profile were used to adjust hourly wind speeds measured at nonstandard anemometer heights to the standard 10-m level. Monthly mean near-surface wind speed series were then derived and subjected to a statistical homogeneity test, with homogeneous monthly mean geostrophic wind (geowind) speed series being used as reference series. Homogenized monthly mean near-surface wind speed series were obtained by adjusting all significant mean shifts, using the results of the statistical test and modeling along with all available metadata, and were used to assess the long-term trends. This study shows that station relocation and anemometer height change are the main causes for discontinuities in the near-surface wind speed series, followed by instrumentation problems or changes, and observing environment changes. It also shows that the effects of artificial mean shifts on the results of trend analysis are remarkable, and that the homogenized near-surface wind speed series show good spatial consistency of trends, which are in agreement with long-term trends estimated from independent datasets, such as surface winds in the United States and cyclone activity indices and ocean wave heights in the region. These indicate success in the homogenization of the wind data. During the period analyzed, the homogenized near-surface wind speed series show significant decreases throughout western Canada and most parts of southern Canada (except the Maritimes) in all seasons, with significant increases in the central Canadian Arctic in all seasons and in the Maritimes in spring and autumn.

Atmospheric Properties Associated With Large Wildfires

1996 ◽  
Vol 6 (2) ◽  
pp. 71 ◽  
Author(s):  
BE Potter
Keyword(s):  
United States ◽  
Wind Shear ◽  
Surface Wind ◽  
Surface Air Temperature ◽  
The United States ◽  
Lower Atmosphere ◽  
Lapse Rate ◽  
Near Surface ◽  
Significance Level ◽  
Lapse Rates

Lower atmosphere moistures, temperatures, winds, and lapse rates are examined for the days of 339 fires over 400 ha in the United States from 1971 through 1984. These quantities are compared with a climatology dataset from the same 14-year period using 2-way unbalanced analysis of variance. The results show that the fire-day surface-air temperature and moisture differ from the climatology at the 0.001 significance level. Near-surface wind shear does not appear to differ significantly between fire and climatology days. Results are inconclusive for wind speed and surface lapse rate.

scholarly journals Effects of Implementing MODIS Land Cover and Albedo in MM5 at Two Contrasting U.S. Regions

2006 ◽  
Vol 7 (5) ◽  
pp. 1043-1060 ◽  
Author(s):  
Ismail Yucel
Keyword(s):  
United States ◽  
Boundary Layer ◽  
Land Cover ◽  
Planetary Boundary Layer ◽  
Land Surface ◽  
Surface Wind ◽  
The United States ◽  
Error Reduction ◽  
Near Surface ◽  
Temperature And Humidity

Abstract This study implements a new land-cover classification and surface albedo from the Moderate Resolution Imaging Spectroradiometer (MODIS) in the fifth-generation Pennsylvania State University–National Center for Atmospheric Research (PSU–NCAR) Mesoscale Model (MM5) and investigates its effects on regional near-surface atmospheric state variables as well as the planetary boundary layer evolution for two dissimilar U.S. regions. Surface parameter datasets are determined by translating the 17-category MODIS classes into the U.S. Geological Survey (USGS) and Simple Biosphere (SiB) categories available for use in MM5. Changes in land-cover specification or associated parameters affected surface wind, temperature, and humidity fields, which, in turn, resulted in perceivable alterations in the evolving structure of the planetary boundary layer. Inclusion of the MODIS albedo into the simulations enhanced these impacts further. Area-averaged comparisons with ground measurements showed remarkable improvements in near-surface temperature and humidity at both study areas when MM5 is initialized with MODIS land-cover and albedo data. Influence of both MODIS surface datasets is more significant at a semiarid location in the southwest of the United States than it is in a humid location in the mid-Atlantic region. Intense summertime surface heating at the semiarid location creates favorable conditions for strong land surface forcing. For example, when the simulations include MODIS land cover and MODIS albedo, respective error reduction rates were 6% and 11% in temperature and 2% and 2.5% in humidity in the southwest of the United States. Error reduction rates in near-surface atmospheric fields are considered important in the design of mesoscale weather simulations.

Recurrence Characteristics Analysis of Near-Surface Wind Speed Signal with Different Sampling Frequencies

2014 ◽  
Vol 599-601 ◽  
pp. 1605-1609 ◽  
Author(s):  
Ming Zeng ◽  
Zhan Xie Wu ◽  
Qing Hao Meng ◽  
Jing Hai Li ◽  
Shu Gen Ma
Keyword(s):  
Wind Speed ◽  
Surface Wind ◽  
Surface Wind Speed ◽  
Recurrence Plot ◽  
Sampling Frequency ◽  
Near Surface ◽  
Gas Leakage ◽  
Time Period ◽  
Characteristics Analysis ◽  
Quantification Analysis

The wind is the main factor to influence the propagation of gas in the atmosphere. Therefore, the wind signal obtained by anemometer will provide us valuable clues for searching gas leakage sources. In this paper, the Recurrence Plot (RP) and Recurrence Quantification Analysis (RQA) are applied to analyze the influence of recurrence characteristics of the wind speed time series under the condition of the same place, the same time period and with the sampling frequency of 1hz, 2hz, 4.2hz, 5hz, 8.3hz, 12.5hz and 16.7hz respectively. Research results show that when the sampling frequency is higher than 5hz, the trends of recurrence nature of different groups are basically unchanged. However, when the sampling frequency is set below 5hz, the original trend of recurrence nature is destroyed, because the recurrence characteristic curves obtained using different sampling frequencies appear cross or overlapping phenomena. The above results indicate that the anemometer will not be able to fully capture the detailed information in wind field when its sampling frequency is lower than 5hz. The recurrence characteristics analysis of the wind speed signals provides an important basis for the optimal selection of anemometer.

A preliminary study on the influence of Beijing urban spatial morphology on near-surface wind speed

Urban Climate ◽  
2020 ◽  
Vol 34 ◽  
pp. 100703
Author(s):  
Yonghong Liu ◽  
Yongming Xu ◽  
Fangmin Zhang ◽  
Wenjun Shu
Keyword(s):  
Wind Speed ◽  
Surface Wind ◽  
Surface Wind Speed ◽  
Near Surface ◽  
Spatial Morphology ◽  
Preliminary Study
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