Causes Of Storms Research Articles

Microbially induced sedimentary structures (MISS) generated by episodic storm surges in a temperate coast

This study recognizes the creation of primary sedimentary structures in a modern environment that reports valuable insights into the role of microbiota in sculpting sedimentary structures, and it may explain many previously confusing sedimentary structures in the rock record. The research considered the frequent flooding events on a coastal sedimentary flat colonized by microbial mats and the effect produced by severe storm surge events. Large-scale microbially induced sedimentary structures (MISS) were created; thus, the interaction between meteorologic, oceanographic, and geomorphologic conditions necessary to form them was analysed. The study was developed in Paso Seco, Argentina (40°38′31” S - 62°12′54” W), a sedimentary flat behind a sand spit, coated by thick microbial mats recurrently affected by storm events. Water level measurements were recorded continuously for five years (measurement interval 10 min). The seawater inundations were related to synoptic weather maps and oceanographic parameters (wave height, period, and tides) to analyse the cause of storm surges. Two situations of severe storms were studied in 2018 and 2019. The inundation of the study area occurs when a cold front in association with a low-pressure centre in the Atlantic Ocean, moving in an SW-NE direction, produces strong SW winds higher than 45 km h−1 and wave height higher than 2 m. Strong winds and storm duration (two or three days) in co-occurrence with spring tides create an extreme erosional event that affects the sedimentary microbial flat. In sum, the interaction between storm surge, high tide, wave setups and wave heights in Paso Seco produces coastal hinterland flooding that creates meter-sized MISS such as roll-ups, erosional pockets, and remnants mats structures. The impact of storm surges on the coast is common and catastrophic in modern times but is challenging to identify in the sedimentary record. Therefore, the microbial structures presented here could help interpret high-energy events occurrence, favourable to assessing past environmental conditions.

Solar Variation and Super Geomagnetic Storm Event during March 10-31, 2015

CMEs and solar flares are important solar ejections which are the cause of storm in Heliosphere. These ejections are producing a change in Earth magnetic field. In this paper we have studied heliospheric disturbance of solar cycle 24 during period from 10 March to 31 March 2015. We observed that a huge explosion of magnetic field and plasma from the Sun’s corona on 15 March 2015 and associated solar flares have disturbed space weather towards earth causes strongest geomagnetic storm on 17 March 2015. We found that Dst value reached to its minimum is -223 nT and a FDs during the period on 17 March 2015.

Characteristics and Causes Analysis of Storm Surges under the Effect of Cold Air Outbreaks in the Bohai Sea

Based on the synchronous tidal data observed from 12 tide stations of the Bohai Sea in a year, the characteristics and causes of storm surges under the effect of cold air outbreaks have been analyzed using the method of harmonic analysis. The results show that the phenomena of abnormal sea-level events are affected remarkably by strong winds due to landform of the Bohai Sea. Under the effect of north and northwest winds, negative storm surges appear successively in the northern part of the Bohai Sea, and in the southern part of the Bohai Sea, first positive storm surges appear and then negative storm surges appear successively. After the wind direction has changed into southerly, the values of negative storm surges decrease gradually, until positive storm surges appear at the tide stations of the Bohai Sea. In the final analysis, maximum negative storm surges or maximum positive storm surges appeared at the tide stations in the southern part of the Bohai Sea lag than that in the northern part. Therefore, in order to provide beneficial service for marine activities, the mariners should pay attention to the positive storm surge on the high water and to the negative storm surge on the low water.

“JUST LIFE IN A NUTSHELL”: HUMOURS AS COMMON SENSE

As evolved creatures, we fit quite well into our environment. We have senses to perceive it, muscles and nerves to act upon it. We do not need to go to university to learn how to walk, talk, run, and distinguish hot from cold, day from night, liquid from solid, dark from bright. Yet we have evolved in such a way that we are capable of wondering how we can jump and run, what it is that makes water cold or hot, how we see, feel, hear, and hurt. If we call common sense the cognitive faculty we are born with, then one part of that common sense is the very faculty to ask basic questions such as those. And given how sophisticated can be our commonsensical questions and answers, ordinary, everyday, “folk” knowledge is worthy of some—expert—study. Clifford Geertz, in his influential “Common Sense as a Cultural System,” called common sense “a relatively organized body of considered thought, rather than just what anyone clothed and in his right mind knows.” The process of posing and answering our own questions consists in the creation of many a “body of considered thought”—of explanatory systems, each constructed according to sets of rules internal to it. One can invoke divinities as the causes of storms and sunlight, or build rituals around natural occurrences, or one can invent a systematic method of enquiry according to which answers are deemed dependable when empirically verifiable and revisable. The former systems are those that anthropologists have long taken seriously and studied, as human phenomena that, once uncovered and looked at from a distance, help us understand our social and biological nature, our societies, and our cognitive makeup. The latter system is the one that yields

Comment on “Interplanetary origin of intense geomagnetic storms (Dst < −100 nT) during solar cycle 23” by W. D. Gonzalez et al.

[1] Gonzalez et al. [2007] studied the interplanetary causes of 87 intense geomagnetic storms (Dst < 100 nT) that occurred during solar cycle 23 (1997–2005). Their classification of interplanetary causes of storms includes CIR (corotating interaction region associated with a high speed stream), MC (magnetic cloud), ‘‘Sh’’ (sheath field with southward component of interplanetary magnetic field), ‘‘Sh + MC’’ (sheath field followed by a magnetic cloud), SBC (a sector boundary crossing), ‘‘S + MC’’ (magnetic cloud compressed by a shock), and ‘‘Complex’’ (for a case in which none of the other cases were identified). The category of ‘‘ICMEs’’ (interplanetary coronal mass ejections) corresponds to several types of structures that are not magnetic clouds, namely that they have not the typical signatures for magnetic clouds [Burlaga et al., 1987]. They found that the most common interplanetary structures leading to the development of an intense storm were magnetic clouds, sheath fields, sheath fields followed by a magnetic cloud and corotating interaction regions leading high speed streams and presented the relative importance of each of those driving structures in three phases of solar cycle: rising, maximum and declining phases. [2] However, the interaction between two CMEs close to the Sun [Gopalswamy et al., 2001, 2002] and between magnetic clouds near the Earth [see, e.g., Burlaga et al., 2001; Berdichevsky et al., 2003; Gonzalez-Esparza et al., 2004; Farrugia et al., 2006a; and references therein] has been reported. A number of papers showed that several strong magnetic storms (see, for instance, events on 31 March, 2001, minimum Dst value of 387 nT, 11–13 April, 2001, Dstmin = 271 nT [Wang et al., 2003]; 28– 30 October, 2003, Dstmin = 363 nT [Veselovsky et al., 2004; Skoug et al., 2004]; 20 November, 2003, Dstmin = 472 nT [Ermolaev et al., 2005]; 8–10 November, 2004, Dstmin = 373 nT [Yermolaev et al., 2005]) have been generating by multiple interacting magnetic clouds. Recently Farrugia et al. [2006b] studied interplanetary conditions for magnetic storms during 1995–2003 and found ‘‘that a significant number of our large events (6 out of 16) consisted of ICMEs/magnetic clouds interacting with each other forming complex ejecta.’’ Xie et al. [2006] studied 37 long-lived geomagnetic storms (LLGMS events) with Dst < 100 nT and the associated CMEs which occurred during 1998–2002 and found that 24 of 37 events were caused by successive CMEs and number of interacting magnetic clouds was observed from 2 up to 4. [3] Thus, classification of interplanetary sources of strong magnetic storms used by Gonzalez et al. [2007] is not complete and does not contain the important category of sources (interacting magnetic clouds) widely discussed in the literature. Therefore, though the obtained results are of limited interest, the used classification excludes from consideration the important mechanism on the solar-terrestrial physics resulting in strong Space Weather events.

Research on Historical Records of Geomagnetic Storms

In recent times, there has been keen interest in understanding Sun-Earth connection events, such as solar flares, CMEs and concomitant magnetic storms. Magnetic storms are the most dramatic and perhaps important component of space weather effects on Earth. Super-intense magnetic storms (defined here as those with Dst −500 nT, where Dst stands for the disturbance storm time index that measures the strength of the magnetic storm) although relatively rare, have the largest societal and technological relevance. Such storms can cause life-threatening power outages, satellite damage, communication failures and navigational problems. However, the data for such magnetic storms is rather scarce. For example, only one super-intense magnetic storm has been recorded (Dst=−640 nT, March 13, 1989) during the space-age (since 1958), although such storms may have occurred many times in the last 160 years or so when the regular observatory network came into existence. Thus, research on historical geomagnetic storms can help to create a good data base for intense and super-intense magnetic storms. From the application of knowledge of interplanetary and solar causes of storms gained from the spaceage observations applied to the super-intense storm of September 1-2, 1859, it has been possible to deduce that an exceptionally fast (and intense) magnetic cloud was the interplanetary cause of this geomagnetic storm with a Dst −1760 nT, nearly 3 times as large as that of March 13, 1989 super-intense storm. The talk will focus on super-intense storms of September 1-2, 1859, and also discuss the results in the context of some recent intense storms.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

On the Martian dust storms

A short review is given of the observational data on the great Martian dust storms. It is noted that these storms are observed at the time of the great oppositions, when Mars is at its perihelion. It is then late spring-early summer in the Southern Hemisphere and the insolation is a maximum. Intense storms were observed during the 1892, 1924, 1941, 1956 and 1971 oppositions, but not in 1909 or 1939. These storms were of various duration and intensity which points out the importance of local time and space meteorological conditions at the moment of storm origin. Storm generation is caused by local conditions, but the fact that they frequently reach global scale implies that there are some feedback processes favoring the global spread of the dust. Possible such processes are described qualitatively together with the causes of storm declines. Those problems of Martian meteorology and micrometeorology are discussed which have to be studied for a better understanding of the generation, development and decay of a dust storm.