On the Regularities of the Spatio-Temporal Distribution of Climatic Characteristics of the Maximum Wind (Syunik Marz, Armenia)

Author(s):  
V.G. Margaryan

The regularities the features of the distribution spatial basic characteristics of the maximum wind speed, as well as the temporal variability of the maximum wind speed in the territory of the Syunik marz of the Republic of Armenia. Data from the Hydrometeorology and Monitoring Center, SNCO of the Ministry of Environment of the Republic of Armenia for a period of 50 years or more (1966-2018) at 6 meteorological stations were used. It is shown that the average long-term speeds of the main characteristics of extreme wind increase in the territory with the height of the terrain, reaching maximum values in the territory with a height of more than 2000-2200 m. Deviation from these patterns is observed in Goris, due to local characteristics. To calculate and predict the maximum average annual wind speed of unexplored territories, correlation annual values of the maximum wind speed, as well as between the annual values of the maximum wind speed and the number of days with a strongwind. It was found that in general throughout the territory of the Syunik marz the annual course of the distribution of the maximum wind speed is not clearly expressed. The highest numbers of days with strong winds are observed in the cold season. For the entire study area there is a decrease in the annual maximum wind speed for the period 1966-2018.

Author(s):  
Masataka YAMAGUCHI ◽  
Kunimitsu INOUCHI ◽  
Yoshihiro UTSUNOMIYA ◽  
Hirokazu NONAKA ◽  
Yoshio HATADA ◽  
...  

Author(s):  
Masafumi KIMIZUKA ◽  
Tomotsuka TAKAYAMA ◽  
Hiroyasu KAWAI ◽  
Masafumi MIYATA ◽  
Katsuya HIRAYAMA ◽  
...  

Author(s):  
M.R. Denadai ◽  
F.B. Santos ◽  
E. Bessa ◽  
L.P. Bernardes ◽  
A. Turra

This study describes the spatio-temporal distribution, population biology, and diet of the puffer fish Lagocephalus laevigatus in Caraguatatuba Bay, south-eastern Brazil. Monthly samples were taken between August 2003 and October 2004 by trawls in two areas, south and north, at depths of 1 to 4 m. The fish were measured and their sex and reproductive stage determined. The abundance of this species was compared between areas and among months, and the items in the diet were identified and quantified. Lagocephalus laevigatus was rare in Caraguatatuba Bay, where only 199 small individuals (4.8 to 15.4 cm) were obtained in the entire study period, suggesting that this species uses the estuary as a nursery. None of the specimens of L. laevigatus captured in Caraguatatuba Bay were sexually mature. Higher densities of L. laevigatus in the bay were recorded in the south area and between October and December 2003, i.e. in the spring, suggesting that spawning may occur from late winter to spring (August through to November). The diet items consumed by L. laevigatus in Caraguatatuba Bay were, as expected from the current literature, crustaceans, mainly amphipods, and fish. However, the most-consumed item was the sea whip Leptogorgia setacea (Cnidaria). This feeding habit may be related to the presence of toxins (tetrodotoxin and saxitoxin) that are frequently found in the skin and viscera of L. laevigatus, which may be sequestered from the sea whip, which possibility still needs to be specifically evaluated.


2019 ◽  
Vol 147 (1) ◽  
pp. 221-245 ◽  
Author(s):  
Guotu Li ◽  
Milan Curcic ◽  
Mohamed Iskandarani ◽  
Shuyi S. Chen ◽  
Omar M. Knio

This study focuses on understanding the evolution of Hurricane Earl (2010) with respect to random perturbations in the storm’s initial strength, size, and asymmetry in wind distribution. We rely on the Unified Wave Interface-Coupled Model (UWIN-CM), a fully coupled atmosphere–wave–ocean system to generate a storm realization ensemble, and use polynomial chaos (PC) expansions to build surrogate models for time evolution of both the maximum wind speed and minimum sea level pressure in Earl. The resulting PC surrogate models provide statistical insights on probability distributions of model responses throughout the simulation time span. Statistical analysis of rapid intensification (RI) suggests that initial perturbations having intensified and counterclockwise-rotated winds are more likely to undergo RI. In addition, for the range of initial conditions considered RI seems mostly sensitive to azimuthally averaged maximum wind speed and asymmetry orientation, rather than storm size and asymmetry magnitude; this is consistent with global sensitivity analysis of PC surrogate models. Finally, we combine initial condition perturbations with a stochastic kinetic energy backscatter scheme (SKEBS) forcing in the UWIN-CM simulations and conclude that the storm tracks are substantially influenced by the SKEBS forcing perturbations, whereas the perturbations in initial conditions alone had only limited impact on the storm-track forecast.


Climate ◽  
2020 ◽  
Vol 8 (5) ◽  
pp. 64 ◽  
Author(s):  
Tayyebeh Mesbahzadeh ◽  
Maryam Mirakbari ◽  
Mohsen Mohseni Saravi ◽  
Farshad Soleimani Sardoo ◽  
Nir Y. Krakauer

Natural disasters such as dust storms are random phenomena created by complicated mechanisms involving many parameters. In this study, we used copula theory for bivariate modeling of dust storms. Copula theory is a suitable method for multivariate modeling of natural disasters. We identified 40 severe dust storms, as defined by the World Meteorological Organization, during 1982–2017 in Yazd province, central Iran. We used parameters at two spatial vertical levels (near-surface and upper atmosphere) that included surface maximum wind speed, and geopotential height and vertical velocity at 500, 850, and 1000 hPa. We compared two bivariate models based on the pairs of maximum wind speed–geopotential height and maximum wind speed–vertical velocity. We determined the bivariate return period using Student t and Gaussian copulas, which were considered as the most suitable functions for these variables. The results obtained for maximum wind speed–geopotential height indicated that the maximum return period was consistent with the observed frequency of severe dust storms. The bivariate modeling of dust storms based on maximum wind speed and geopotential height better described the conditions of severe dust storms than modeling based on maximum wind speed and vertical velocity. The finding of this study can be useful to improve risk management and mitigate the impacts of severe dust storms.


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