Recent Megafires Provide a Tipping Point for Desertification of Conifer Ecosystems

Recent megafires and gigafires are contributing to the desertification of conifer forest ecosystems due to their size and severity. Megafires have been increasing in their frequency in the past two decades of the 21st century. They are classed as such because of being 40,469 to 404,694 ha in size, having high complexity, resisting suppression, and producing desertification due to erosion and vegetation type conversion. Increasingly, gigafires (>404,694 ha) are impacting coniferous forest ecosystems. These were once thought of as only pre-20th century phenomena when fire suppression was in its infancy. Climate change is an insidious inciting factor in large wildfire occurrences. Fire seasons are longer, drier, hotter, and windier due to changes in basic meteorology. Conifer forests have accumulated high fuel loads in the 20th and 21st centuries. Ignition sources in conifer forests have increased as well due to human activities, economic development, and population demographics. Natural ignitions from lightning are increasing as a result of greater severe thunderstorm activity. Drought has predisposed these forests to easy fire ignition and spread. Wildfires are more likely to produce vegetation shifts from conifers to scrublands or grasslands, especially when wildfires occur with higher frequency and severity. Severe erosion after megafires has the collateral damage of reducing conifer resilience and sustainability.

Monsoon onset and reservoir build up- A case Study for Hirakud

Onset of monsoon for each year of the period from 1961 to 1986 over the Upper Mahanadi basin has been studied taking into consideration the sharp increase in water levels of the Hirakud reservoir. This study has shown that .there are positive and negative time-lags in the arrival of monsoon run off into the reservoir. It has been seen that positive time lags are due to antecedent condition of the basin before the onset of monsoon while negative time-lag appears to be due to pre-monsoon thunderstorm activity which causes reservoir levels to increase before the onset of monsoon. Attempt has been made to discuss all these cases briefly. It has been seen that on a majority of occasions monsoon runoff has reached the reservoir with a time-lag of 1 to 4 days.

Some climatological features of thunderstorms at Thiruvananthapuram, Kochi and Kozhikode airports

The average monthly frequency of thunderstorms, its annual and monthly frequency of duration, time of commencement and frequency of thunderstorms in relation to duration and time of commencement at three aerodrome stations of Thiruvananthapuram, Kochi and Kozhikode have been presented in this paper. It is found that thunderstorm activity is maximum in pre-monsoon months at Thiruvananthapuram and Kochi and in post monsoon months at Kozhikode. Majority of the thunderstorms are of duration less than three hours and have a preference to commence between 9 and 18 UTC in all stations whereas long duration thunderstorms generally commence between 9 and 15 UTC.

Forecasting peak surface gust wind in association with thunderstorm activity during pre-monsoon season at Delhi

In this study, an attempt is made to develop an objective method for forecasting the direction and speed of the gusty winds associated with thunderstorms at Delhi. For this purpose, surface and upper-air data for April, May and June (AMJ) for the years 1985-90 are utilized. Multiple regression equations are developed for forecasting the direction and speed of the gusty winds, using stepwise screening method, for which a total of 181 potential predictors are utilized. The developed dynamical-statistical models are tested with independent data sets of 1994 and 1995 for April, May and June. The dynamical-statistical models give satisfactory results with the developmental as well as the independent data sets. The root mean square error of the direction vary between 58° and 77° and the speed forecast vary between 9 and 12 knots. Possible reasons for large deviations of the forecast, noticed on a very few occasions, have also been examined.

Cluster analysis of lightning discharges: based on Vereya-MR network data

Monitoring thunderstorm activity can help you solve many problems such as infrastructure facility protection, warning of hazardous phenomena associated with intense precipitation, study of conditions for the occurrence of thunderstorms and the degree of their influence on human activity, as well as the influence of thunderstorm activity on the formation of near-Earth space. We investigate the characteristics of thunderstorm cells by the method of cluster analysis. We take the Vereya-MR network data accumulated over a period from 2012 to 2018 as a basis. The Vereya-MR network considered in this paper is included in networks operating in the VLF-LF range (long and super-long radio waves). Reception points equipped with recording equipment, primary information processing systems, communication systems, precision time and positioning devices based on global satellite navigation systems are located throughout Russia. In the longitudinal-latitudinal thunderstorm distributions of interest, the dependence on the location of recording devices might be manifested. We compare the behavior of thunderstorms on the entire territory of the Russian Federation with those in the Baikal natural territory. We have established the power of thunderstorms over the Baikal region is lower. The daily variation in thunderstorm cells we obtained is consistent with the data from other works. There are no differences in other thunderstorm characteristics between the regions under study. This might be due to peculiarities of the analysis method. On the basis of the work performed, we propose sites for new points of our own lightning location network, as well as additional methods of cluster analysis.

Cluster analysis of lightning discharges: based on Vereya-MR network data

Monitoring thunderstorm activity can help you solve many problems such as infrastructure facility protection, warning of hazardous phenomena associated with intense precipitation, study of conditions for the occurrence of thunderstorms and the degree of their influence on human activity, as well as the influence of thunderstorm activity on the formation of near-Earth space. We investigate the characteristics of thunderstorm cells by the method of cluster analysis. We take the Vereya-MR network data accumulated over a period from 2012 to 2018 as a basis. The Vereya-MR network considered in this paper is included in networks operating in the VLF-LF range (long and super-long radio waves). Reception points equipped with recording equipment, primary information processing systems, communication systems, precision time and positioning devices based on global satellite navigation systems are located throughout Russia. In the longitudinal-latitudinal thunderstorm distributions of interest, the dependence on the location of recording devices might be manifested. We compare the behavior of thunderstorms on the entire territory of the Russian Federation with those in the Baikal natural territory. We have established the power of thunderstorms over the Baikal region is lower. The daily variation in thunderstorm cells we obtained is consistent with the data from other works. There are no differences in other thunderstorm characteristics between the regions under study. This might be due to peculiarities of the analysis method. On the basis of the work performed, we propose sites for new points of our own lightning location network, as well as additional methods of cluster analysis.

Study of thunderstorm activity in Volyn Region and in Ukraine using the data of Blitzortung online resource

The article contains the results of statistical and graphical analysis of thunderstorm activity in Ukraine and within Volyn Region, in particular, following the study of the dynamic maps archive available at the online resource Blitzortung.org (lightnings and thunderstorms in real time). It describes the principles and results of activities of Blitzortung.org, a community of lightning direction sensors owners and users, and presents the developed algorithm of the methodology of reading dynamic maps available at this resource. Regional analysis of the archival maps on the website Blitzortung.org for 2008-2019 for the territory of Volyn Region made it possible to establish the following changes of the thunderstorm activity dynamics: the total number of thunderstorm days more than doubled (from 30 to 68.3 days on average); the number of thunderstorms increased in April (it was a rare phenomenon earlier); the number of thunderstorms increased significantly in May, for some years the number of thunderstorm days in May reached certain summer months (June and July); most thunderstorms are of frontal origin, storm fronts come from the west, north and southwest. The number of frontal thunderstorms tends to increase, therefore indicating increased atmospheric instability and the number of natural meteorological phenomena associated with such instability; the average monthly number of thunderstorm days in Volyn Region also increased for all months of the year with no exception. The analysis of storm activity within the whole territory of Ukraine during the period of 2018-2019 indicated the presence of clear regional features and differences. The increase in thunderstorm activity is observed in the western (50-100%) and southern (15-50%) regions of the country, and partly in the north. The number of thunderstorm days in the eastern part of Ukraine is close to the climatic normal. At the same time, the analysis needs to be clarified and detailed throughout the whole network of meteorological stations of Ukraine whose data can be compared with the results of the study of archival maps available at Blitzortung.org.

ACTIVE PROTECTION METHOD FOR POWER SUPPLY OF MICROPROCESSOR COMPLEXES OF RAILWAY AUTOMATION AND REMOTE CONTROL

The article discusses the issues of increasing the reliability, safety, and survivability of power supply for railway automation and remote control devices. The authors have analyzed failures in the automation and remote control facilities in recent years, estimated the proportion of device failures due to lightning overvoltages, and highlighted an upward trend in the railway automation and remote control failures due to switching and lightning overvoltages. The design of modern uninterruptible power supply devices is provided with a description of the main structural units. Methods are proposed for the implementation of active protection for power supply of railway automation and remote control by introducing the thunderstorm locating functionality into the technical diagnostics and monitoring system. This solution will enable registration of hazardous thunderstorm activity and maintaining the devices’ serviceability and effi ciency, and will ensure the continuity and safety of the transportation process, which will help reduce damage incurred due to hazardous electromagnetic eff ects, including lightning overvoltages. The article suggests synchronizing the thunderstorm location system with the existing lightning detection networks through the Internet, a global computer network, as well as the option of installing a single-point lightning detector at an electrical interlocking post.