What Factors Contributed to the Torrential Rainfall of Hurricane Harvey over Texas?

2020 ◽  
Vol 15 (6) ◽  
pp. 726-734
Author(s):  
Satoshi Iizuka ◽  
◽  
Naoki Sakai
Keyword(s):  
Tropical Cyclone ◽  
Residence Time ◽  
Rainfall Intensity ◽  
Extreme Rainfall ◽  
Rainfall Rate ◽  
Area Coverage ◽  
Lower Atmosphere ◽  
Central Coast ◽  
Torrential Rainfall

In August 2017, Hurricane Harvey brought an unprecedented amount of rainfall and catastrophic flooding to the Houston metropolitan area, as it stalled near the coast of Texas for several days after weakening to a tropical storm intensity. The present study examines the relationship between tropical cyclone rainfall totals over Texas and the track, residence time, rainfall intensity, and rainfall area coverage of past tropical cyclones that approached Texas after 1979. The most significant factor affecting rainfall totals over Texas is whether a tropical cyclone makes landfall on the central coast of Texas and travel inland. Another significant factor is the length of time a tropical cyclone resides near Texas. Rainfall intensity also contributes in part to rainfall totals over Texas, whereas contribution of rainfall area coverage is not significant. The track of a tropical cyclone traveling near Texas is controlled by the steering winds over Texas, while its residence time near Texas is related partly to the meandering of the subtropical jets. Rainfall rate depends on the intensity of tropical cyclone. No significant relationship between rainfall intensity and environmental moisture in the lower atmosphere is found in the present analysis. Furthermore, the extreme rainfall totals over Texas induced by Harvey can be attributed to the combined effect of extreme long-term stalling of Harvey near the central coast of Texas and the higher rainfall rate.

scholarly journals Radar and Rain Gauge Analysis of the Extreme Rainfall during Hurricane Danny’s (1997) Landfall

2007 ◽  
Vol 135 (5) ◽  
pp. 1869-1888 ◽  
Author(s):  
Jeffrey M. Medlin ◽  
Sytske K. Kimball ◽  
Keith G. Blackwell
Keyword(s):  
Inner Core ◽  
Temporal Distribution ◽  
Extreme Rainfall ◽  
Rain Gauge ◽  
Rainfall Amount ◽  
Mobile Bay ◽  
Maximum Rainfall ◽  
Torrential Rainfall ◽  
First Time

Abstract As a minimal hurricane, Danny moved over Mobile Bay around 0900 UTC 19 July 1997 and became stationary by midmorning, while situated within a synoptic col. Danny then evolved into an asymmetric storm with an intensely convective rainband that produced torrential rainfall through 1200 UTC 20 July 1997. Danny’s center remained <100 km from the National Weather Service (NWS) Weather Surveillance Radar-1988 Doppler (WSR-88D) in Mobile, Alabama, for over 48 h, allowing long-term surveillance of the storm’s inner core. This event marked the first time the tropical Z–R relationship was employed on an operational WSR-88D system during tropical cyclone landfall. A radar-estimated maximum rainfall accumulation of 1097 mm (43.2 in.) was analyzed over southwestern Mobile Bay. A NWS cooperative rain gauge located on Dauphin Island, Alabama, measured 896 mm (35.28 in.). An adjacent standard rain gauge measured the highest rainfall amount of 932 mm (36.71 in.). This paper investigates the spatial and temporal distribution and potential magnitude of Danny’s torrential rainfall episode over coastal Alabama. It is shown that both gauges and radar seriously underestimated event rainfall. An estimate is given for what could have been the true event rainfall amount. In the case of the radar, the WSR-88D Algorithm Testing and Display System is used to obtain a better estimate of rainfall using higher dBZ caps than the operational 50 dBZ. In the case of the tipping-bucket rain gauge, wind and mechanical error estimates were applied in order to quantify rainfall underestimation.

scholarly journals Cross Validation of Rainfall Characteristics Estimated from the TRMM PR, a Combined PR–TMI Algorithm, and a C-POL Ground Radar during the Passage of Tropical Cyclone and Nontropical Cyclone Events over Darwin, Australia

2018 ◽  
Vol 35 (12) ◽  
pp. 2339-2358 ◽  
Author(s):  
Anil Deo ◽  
S. Joseph Munchak ◽  
Kevin J. E. Walsh
Keyword(s):  
Tropical Cyclone ◽  
Tropical Rainfall Measuring Mission ◽  
Rainfall Rate ◽  
Rainfall Characteristics ◽  
Significant Difference ◽  
Median Volume ◽  
Precipitation Type ◽  
Correct Direction ◽  
Microwave Imager ◽  
Trmm Microwave Imager

AbstractThis study cross validates the radar reflectivity Z; the rainfall drop size distribution parameter (median volume diameter Do); and the rainfall rate R estimated from the Tropical Rainfall Measuring Mission (TRMM) satellite Precipitation Radar (PR), a combined PR and TRMM Microwave Imager (TMI) algorithm (COM), and a C-band dual-polarized ground radar (GR) for TRMM overpasses during the passage of tropical cyclone (TC) and non-TC events over Darwin, Australia. Two overpass events during the passage of TC Carlos and 11 non-TC overpass events are used in this study, and the GR is taken as the reference. It is shown that the correspondence is dependent on the precipitation type whereby events with more (less) stratiform rainfall usually have a positive (negative) bias in the reflectivity and the rainfall rate, whereas in the Do the bias is generally positive but small (large). The COM reflectivity estimates are similar to the PR, but it has a smaller bias in the Do for most of the greater stratiform events. This suggests that combining the TMI with the PR adjusts the Do toward the “correct” direction if the GR is taken as the reference. Moreover, the association between the TRMM estimates and the GR for the two TC events, which are highly stratiform in nature, is similar to that observed for the highly stratiform non-TC events (there is no significant difference), but it differs considerably from that observed for the majority of the highly convective non-TC events.

scholarly journals Tropical cyclone contribution to extreme rainfall over southwest Pacific Island nations

2021 ◽  
Author(s):  
Anil Deo ◽  
Savin S. Chand ◽  
Hamish Ramsay ◽  
Neil J. Holbrook ◽  
Simon McGree ◽  
...  
Keyword(s):  
Tropical Cyclone ◽  
El Niño ◽  
El Nino ◽  
Extreme Rainfall ◽  
Pacific Island ◽  
Extreme Rainfall Events ◽  
Rainfall Events ◽  
Southwest Pacific ◽  
Inactive Phase ◽  
Pacific Island Nations

AbstractSouthwest Pacific nations are among some of the worst impacted and most vulnerable globally in terms of tropical cyclone (TC)-induced flooding and accompanying risks. This study objectively quantifies the fractional contribution of TCs to extreme rainfall (hereafter, TC contributions) in the context of climate variability and change. We show that TC contributions to extreme rainfall are substantially enhanced during active phases of the Madden–Julian Oscillation and by El Niño conditions (particularly over the eastern southwest Pacific region); this enhancement is primarily attributed to increased TC activity during these event periods. There are also indications of increasing intensities of TC-induced extreme rainfall events over the past few decades. A key part of this work involves development of sophisticated Bayesian regression models for individual island nations in order to better understand the synergistic relationships between TC-induced extreme rainfall and combinations of various climatic drivers that modulate the relationship. Such models are found to be very useful for not only assessing probabilities of TC- and non-TC induced extreme rainfall events but also evaluating probabilities of extreme rainfall for cases with different underlying climatic conditions. For example, TC-induced extreme rainfall probability over Samoa can vary from ~ 95 to ~ 75% during a La Niña period, if it coincides with an active or inactive phase of the MJO, and can be reduced to ~ 30% during a combination of El Niño period and inactive phase of the MJO. Several other such cases have been assessed for different island nations, providing information that have potentially important implications for planning and preparing for TC risks in vulnerable Pacific Island nations.

scholarly journals Understanding the Processes Causing the Early Intensification of Hurricane Dorian through an Ensemble of the Hurricane Analysis and Forecast System (HAFS)

Atmosphere ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 93
Author(s):  
Andrew Hazelton ◽  
Ghassan J. Alaka ◽  
Levi Cowan ◽  
Michael Fischer ◽  
Sundararaman Gopalakrishnan
Keyword(s):  
Tropical Cyclone ◽  
Large Scale ◽  
Early Stage ◽  
Early Period ◽  
Storm Track ◽  
Key Factors ◽  
Complex Interplay ◽  
Forecast System ◽  
Model Initialization

The early stages of a tropical cyclone can be a challenge to forecast, as a storm consolidates and begins to grow based on the local and environmental conditions. A high-resolution ensemble of the Hurricane Analysis and Forecast System (HAFS) is used to study the early intensification of Hurricane Dorian, a catastrophic 2019 storm in which the early period proved challenging for forecasters. There was a clear connection in the ensemble between early storm track and intensity: stronger members moved more northeast initially, although this result did not have much impact on the long-term track. The ensemble results show several key factors determining the early evolution of Dorian. Large-scale divergence northeast of the tropical cyclone (TC) appeared to favor intensification, and this structure was present at model initialization. There was also greater moisture northeast of the TC for stronger members at initialization, favoring more intensification and downshear development of the circulation as these members evolved. This study highlights the complex interplay between synoptic and storm scale processes in the development and intensification of early-stage tropical cyclones.

scholarly journals Trends in the Frequency of Intense Precipitation Events in Southern and Southeastern Brazil during 1960–2004

2011 ◽  
Vol 24 (7) ◽  
pp. 1913-1921 ◽  
Author(s):  
Mateus da Silva Teixeira ◽  
Prakki Satyamurty
Keyword(s):  
Extreme Rainfall ◽  
Southeastern Brazil ◽  
Extreme Rainfall Event ◽  
Southern Brazil ◽  
Extreme Rainfall Events ◽  
Rainfall Events ◽  
Annual Frequency ◽  
Long Term Trends ◽  
Increasing Trends

Abstract A new approach to define heavy and extreme rainfall events based on cluster analysis and area-average rainfall series is presented. The annual frequency of the heavy and extreme rainfall events is obtained for the southeastern and southern Brazil regions. In the 1960–2004 period, 510 (98) and 466 (77) heavy (extreme) rainfall events are identified in the two regions. Monthly distributions of the events closely follow the monthly climatological rainfall in the two regions. In both regions, annual heavy and extreme rainfall event frequencies present increasing trends in the 45-yr period. However, only in southern Brazil is the trend statistically significant. Although longer time series are necessary to ensure the existence of long-term trends, the positive trends are somewhat alarming since they indicate that climate changes, in terms of rainfall regimes, are possibly under way in Brazil.

Long-term monitoring of layering of lower atmosphere in urban environments by ceilometer

2007 ◽  
Author(s):  
Klaus Schäfer ◽  
Stefan Emeis ◽  
Carsten Jahn ◽  
Christoph Münkel ◽  
Caroline Münsterer ◽  
...  
Keyword(s):  
Urban Environments ◽  
Lower Atmosphere ◽  
Long Term Monitoring ◽  
Term Monitoring

Mathematical modeling of fluid movement inside the eyeball during intravitreal injection

2021 ◽  
pp. 106-109
Author(s):  
D.V. Lipatov ◽  
◽  
S.A. Skladchikov ◽  
N.P. Savenkova ◽  
V.V. Novoderezkin ◽  
...  
Keyword(s):  
Mathematical Modeling ◽  
Mathematical Model ◽  
Residence Time ◽  
Complex Structure ◽  
Posterior Vitreous Detachment ◽  
Vitreous Body ◽  
Complete Removal ◽  
Intravitreal Injections ◽  
The World

Background. The avalanche-like growth of intravitreal injections in the world has significantly increased interest in the hemodynamics of the processes that occur in the eye when a drug is injected into the vitreous cavity. Every year, the number of intravitreally used drugs and promising areas in which they can be used is growing. This also applies to the creation of new combined medicines and the development of drugs with a long-term therapeutic effect. Aims. Create mathematical model of eyeball to evaluate the movement of the drug substance in it; to estimate the time of the drug's presence in the eye cavity before its complete removal, to characterize the ways of its removal from the eye cavity; to assess the significance of posterior vitreous detachment during the time when the drug is present in the eye cavity; to evaluate the effect on the hydrodynamics of the depth of drug administration. Results. When the drug is administered closer to the center of the eyeball, its residence time increases in comparison with the parietal administration. With a complete posterior detachment of the vitreous body, the time of finding the drug in the eye is prolonged compared to its absence. The obtained results of mathematical modeling of the movement of the drug administered intravitreally cannot be mechanically transferred to the human eye, due to the more complex structure of the latter. Key words: intravitreal injections, vitreous body, mathematic computing.

Specific features of estimating calculated rainfall rates with account of extreme rain showers

2021 ◽  
pp. 50-55
Author(s):  
С.Н. Волков ◽  
А.И. Житенев ◽  
О.Н. Рублевская ◽  
Ю.А. Курганов ◽  
И.Г. Костенко ◽  
...  
Keyword(s):  
Rainfall Intensity ◽  
Experimental Studies ◽  
Measurement Data ◽  
Extreme Rainfall ◽  
Experimental Information ◽  
Wastewater Disposal ◽  
Rain Gauges ◽  
Experimental Base ◽  
Extreme Rain ◽  
Official Data

Анализ официальных источников информации показывает, что распределение экстремальных дождей по территории происходит с учетом микроклиматических особенностей ее местности. Для оценки степени достоверности таких закономерностей в пределах мегаполисов проведены экспериментальные исследования, в которых в качестве экспериментальной базы принята система водоотведения Санкт-Петербурга, в качестве средств измерения – сеть из 34 автоматических осадкомеров, осуществляющих записи с интервалом 5 минут, в качестве экспериментальной информации – база данных результатов измерений в течение шести лет. В результате исследований установлено, что в городской среде формируется микроклимат, отличающийся от климата за ее пределами. Кроме того, в масштабах мегаполисов имеются микроклиматические зоны, в которых зависимости интенсивностей осадков от их повторяемости могут существенно отличаться. При этом отличия начинают проявляться при периодах р однократного превышения расчетной интенсивности дождей от 1,5–2 лет, а при их меньших значениях отличия не выявлены. Полученный результат согласуется с данными исследований других авторов, экспериментально установивших, что количество экстремальных дождей увеличивается в тех районах мегаполисов, как правило, исторических,в которых меньше зеленых насаждений и, соответственно, более высокая степень перегрева поверхности в летнее время. The analysis of official data resources shows that the distribution of extreme rainfall over the territory is carried out with account of the microclimatic features of the area. To estimate the degree of reliability of such patterns within megalopolises, experimental studies were carried out, where the wastewater disposal system of St. Petersburg was assumed as an experimental base; a network of 34 automatic rain gauges recording with an interval of 5 minutes was assumed as a measuring instrument, and a base was used as experimental information, i. e., a measurement data base for six years. As a result of the research, it has been established that a microclimate is formed in the urban environment that differs from the climate outside it. Besides, on a megacity scale, there are microclimatic zones where the dependences of precipitation intensities on their frequency can differ significantly. In this case, the differences begin to manifest at periods p of one-time excess of the calculated rainfall intensity from 1.5–2 years, whereas at lower values, no differences have been found. The result obtained is consistent with the research data obtained by other authors, who experimentally established that the amount of extreme rainfall increased in those areas of megacities, as a rule, historical ones, where fewer green spaces are located, and, accordingly, a higher degree of surface overheating in summer is recorded.

Detection and residence time of bisphosphonates in bone of horses

2021 ◽  
Vol 34 (1) ◽  
pp. 23-27
Author(s):  
Heather K. Knych ◽  
Jennifer Janes ◽  
Laura Kennedy ◽  
Daniel S. McKemie ◽  
Rick M. Arthur ◽  
...  
Keyword(s):  
Synovial Fluid ◽  
Residence Time ◽  
Bone Fractures ◽  
Limited Information ◽  
Long Term Effects ◽  
Normal Bone ◽  
Postmortem Blood ◽  
Affect Bone Healing ◽  
Postmortem Sample

Bisphosphonates are potent anti-resorptive agents that have the potential to adversely affect bone healing in equine athletes, and normal bone adaption in young racehorses. A concern exists that bisphosphonate inhibition of normal bone metabolism could lead to increased bone fractures during high-intensity exercise. We found only a single report describing concentrations of tiludronate in the bone of horses, and no studies describing clodronate. Knowledge of the residence time in bone could allow for a better understanding of the long-term effects of these compounds. Our objectives were to develop a method for detection of bisphosphonates in bone and add to the limited information available regarding the disposition of these drugs in the bone of horses. Two horses received clodronate and 2 tiludronate disodium. Postmortem collection of bones and teeth occurred either 4 or 30 d post drug administration. Additionally, postmortem blood, synovial fluid, aqueous humor, and bone samples from racehorses with various histories of bisphosphonate administration were collected, and concentrations determined using the developed LC-MS/MS method. Bisphosphonates were detected in bones and teeth tested at 4 and 30 d. In a postmortem sample, clodronate was detected in bone from a horse with reported administration 18 mo prior; clodronate was not detected in other sample types collected from this horse. Bisphosphonates reside in bone for extended periods of time, which could lead to potential long-term effects, increasing the potential for bone fractures in young and/or athletic horses.

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