Seasonality and trends in human- and lightning-caused wildfires ≥ 2 ha in Canada, 1959–2018

2020 ◽  
Vol 29 (6) ◽  
pp. 473 ◽  
Author(s):  
Sean C. P. Coogan ◽  
Xinli Cai ◽  
Piyush Jain ◽  
Mike D. Flannigan

We examined the seasonal distribution of lightning- and human-caused wildfires ≥ 2ha in Canada for two time periods: 1959–2018 and 1981–2018. Furthermore, we investigated trends in seasonality, number of fires per year and number of days with fire starts per year for human- and lightning-caused fires. Nationally, lightning fires peaked from June to August, whereas human fires peaked during May. There was, however, notable variation in the seasonal distributions of human- and lightning-caused fires between ecozones. Likewise, trends in season start and end dates varied among ecozones and time series, with trends generally being stronger for human-caused fires. Trends in the number of fires from 1959 to 2018 suggested significant increases in the number of lightning-caused fires and days with lightning ignitions across almost all ecozones, while from 1981 to 2018 there was a significantly decreasing trend in the number of human-caused fires and days with human ignitions in almost all ecozones. The highest densities of human-caused fires occurred in the Montane Cordillera and Atlantic Maritime, while the highest density of lightning-caused fires occurred in the Boreal Shield West. The Montane Cordillera and Taiga Shield West showed significant increases in the number of lightning fires and days with lightning ignitions across both time series.

Author(s):  
W.P. De Lange

The Greenhouse Effect acts to slow the escape of infrared radiation to space, and hence warms the atmosphere. The oceans derive almost all of their thermal energy from the sun, and none from infrared radiation in the atmosphere. The thermal energy stored by the oceans is transported globally and released after a range of different time periods. The release of thermal energy from the oceans modifies the behaviour of atmospheric circulation, and hence varies climate. Based on ocean behaviour, New Zealand can expect weather patterns similar to those from 1890-1922 and another Little Ice Age may develop this century.


2020 ◽  
Vol 9 (s1) ◽  
Author(s):  
Babak Jamshidi ◽  
Shahriar Jamshidi Zargaran ◽  
Mansour Rezaei

AbstractIntroductionTime series models are one of the frequently used methods to describe the pattern of spreading an epidemic.MethodsWe presented a new family of time series models able to represent the cumulative number of individuals that contracted an infectious disease from the start to the end of the first wave of spreading. This family is flexible enough to model the propagation of almost all infectious diseases. After a general discussion on competent time series to model the outbreak of a communicable disease, we introduced the new family through one of its examples.ResultsWe estimated the parameters of two samples of the novel family to model the spreading of COVID-19 in China.DiscussionOur model does not work well when the decreasing trend of the rate of growth is absent because it is the main presumption of the model. In addition, since the information on the initial days is of the utmost importance for this model, one of the challenges about this model is modifying it to get qualified to model datasets that lack the information on the first days.


2016 ◽  
Vol 19 (03) ◽  
pp. 1650014 ◽  
Author(s):  
Pieter T. Elgers ◽  
May H. Lo ◽  
Wenjuan Xie ◽  
Le Emily Xu

This study addresses the impact of firm- and time-specific attributes on the accuracy of composite forecasts of annual earnings, constructed from time-series, price-based, and analysts' forecasts. The attributes examined include firm size, analysts' coverage, and time periods pre-dating and following the implementation of regulation fair disclosure. Our results indicate that the relative accuracy of the composite forecasts is time-specific. In the pre-regulation fair disclosure period, composite forecasts significantly outperform each of the three individual forecast sources. Moreover, the extent of improvement in accuracy of composite forecasts is significantly higher for the smaller and lightly-covered firms. Collectively, these results suggest that the predictive accuracy of composite forecasts is contextual.


GPS Solutions ◽  
2021 ◽  
Vol 25 (3) ◽  
Author(s):  
Anna Klos ◽  
Henryk Dobslaw ◽  
Robert Dill ◽  
Janusz Bogusz

AbstractWe examine the sensitivity of the Global Positioning System (GPS) to non-tidal loading for a set of continental Eurasia permanent stations. We utilized daily vertical displacements available from the Nevada Geodetic Laboratory (NGL) at stations located at least 100 km away from the coast. Loading-induced predictions of displacements of earth’s crust are provided by the Earth-System-Modeling Group of the GFZ (ESMGFZ). We demonstrate that the hydrological loading, supported by barystatic sea-level changes to close the global mass budget (HYDL + SLEL), contributes to GPS displacements only in the seasonal band. Non-tidal atmospheric loading, supported by non-tidal oceanic loading (NTAL + NTOL), correlates positively with GPS displacements for almost all time resolutions, including non-seasonal changes from 2 days to 5 months, which are often considered as noise, intra-seasonal and seasonal changes with periods between 4 months and 1.4 years, and, also, inter-annual signals between 1.1 and 3.0 years. Correcting the GPS vertical displacements by NTAL leads to a reduction in the time series variances, evoking a whitening of the GPS stochastic character and a decrease in the standard deviation of noise. Both lead, on average, to an improvement in the uncertainty of the GPS vertical velocity by a factor of 2. To reduce its impact on the GPS displacement time series, we recommend that NTAL is applied at the observation level during the processing of GPS observations. HYDL might be corrected at the observation level or remain in the data and be applied at the stage of time series analysis.


2021 ◽  
Vol 25 (1) ◽  
pp. 26-35
Author(s):  
G.K. Deshmukh ◽  
Sanskrity Joseph ◽  
Asha Sahu

Corporate social Responsibility has become a buzz word in recent times. Its worldwide acceptance due to the social consciousness of enterprises coupled with legal orientation in developing countries like India has made it one of the most researched issue for researchers across continents. This paper is an attempt to review the development in the core concepts and theories which have been put forwarded by different researchers during the time period of 2010-2018. The paper undergoes a time series analysis for the selected period evaluating the evolution and impact assessment of CSR on core managerial concepts like marketing, finance and Human Resource management. The researchers after time series analysis have concluded that CSR is age long practice which has changed its orientation with the changes in objectives of business. It can be easily classified in three conceptual eras on the basis of its objectives. In the initial era it was a self-driven practice mainly influenced by the values of promoters of business. In the later stages it can be related with a business strategy of gaining goodwill. In the present era corporates have understood the value of societal obligation and it has again become a self-driven exercise. Further the impact of CSR has coupled with almost all functions of management which can be easily understood from the host of studies conducted during the selected period. The selected studies indicate that CSR has been instrumental in increasing net worth, customer satisfaction and employee retention.


2015 ◽  
Vol 22 (4) ◽  
pp. 377-382 ◽  
Author(s):  
G. Wang ◽  
X. Chen

Abstract. Almost all climate time series have some degree of nonstationarity due to external driving forces perturbing the observed system. Therefore, these external driving forces should be taken into account when constructing the climate dynamics. This paper presents a new technique of obtaining the driving forces of a time series from the slow feature analysis (SFA) approach, and then introduces them into a predictive model to predict nonstationary time series. The basic theory of the technique is to consider the driving forces as state variables and to incorporate them into the predictive model. Experiments using a modified logistic time series and winter ozone data in Arosa, Switzerland, were conducted to test the model. The results showed improved prediction skills.


1998 ◽  
Vol 08 (04) ◽  
pp. 799-803 ◽  
Author(s):  
D. M. Sonechkin

Based on the heat balance equation of the global climate system the well-known surface air temperature time series of the Northern and Southern hemispheres were analyzed as realizations of a fractional Brownian motion. The technique of the so-called wavelet transform was used for this purpose. The technique easily admits splitting time series of interest to statistically stationary oscillations and a trend. Such temperature oscillations were extracted which include within themselves almost all differences between both hemispheric time series. As a result of subtraction of the oscillations from the primary hemispheric series a residual trend-like component was evaluated. The latter evidences a single warming trend of the global climate system that was started from the early 20th century.


2021 ◽  
Author(s):  
◽  
Krunoslav Puškar

This thesis deals with the analysis and description of the historical and contemporary anthroponymy of the Kalnik area of the Prigorje region on the basis of both archival and field research carried out throughout a longer period of time. Since there has not been any extensive onomastic reasearch in the very area to date, our goal was to determine the influence of linguistic and extralinguistic changes in the reaserched onomastic categories. The introduction of this thesis provides the geographical, sociohistorical, demographical and linguistic context of the researched area, whereas the subsequent chapters provide a list and analysis of confirmed first names, personal and family nicknames, as well as family names of the reaserched area. First names were researched during nine time periods with a duration of five years, beginning from 1802 and ending in 2014. Because of a wide researched area, we limited our research on the anthroponymic repertoire of the city of Križevci, in which 3020 first names (1579 male and 1441 female names) were confirmed. In the 19th century, during five analysed time periods, 1519 first names were confirmed, out of which 814 male and 705 female names, which were mostly simple based on their structure (91.64%). Concerning the provenance of the first names, we established that almost all names were either Christian names or translated Christian names and that national names occur very rarely and sporadically, only in the second half of the 19th century. By comparison, in the 20th and 21st century, during the last four time periods, 1501 first names have been confirmed, out of which 765 were male and 736 female names. Concerning their structure, they turned out to be mostly compound first names in the 1946- 1950 time period (55.69%), whereas in the 2010-2014 time period they turned out to be predominantly single (97.02%). Concerning their provenance, in the 1946-1950 time period 48.39% of male and 57.58% of female national names were confirmed, whereas in the last time period male national names amount to 4.05%, and female national names to only 1.27%. Personal nicknames are a special anthroponymic category which has not been researched in the Kalnik area. Having limited our field research on 13 places throughout the area, we confirmed 288 real personal nicknames, 245 male and 43 female nicknames, of mostly simple structure (95.14%), which are still mostly used in oral and informal communication. The motivation behind the nicknames has faithfully shown us the extralinguistic reality of the researched area. The most frequent motivational group of nicknames is the one of unknown motivation (23.96%), while the other confirmed groups are nicknames motivated by a first name (12,15%), a physical characteristic of the owner (12.15%), another characteristic of the owner (11,81%), a specific word used by the owner (8.33%), an animal (6.94%), a family name (6.60%), an occupation (6.25%), an ethnonym or toponym (4.51%), a family or social role (2.78%), a professional designation (1.38%), food (1.04%), a name for a plant (1.04%), a subject (0.69%), and another nickname (0.35%). The high frequency of nicknames of unknown motivation shows us the importance of future research of this anthroponymic category because, due to the passage of time, it is difficult to determine the real motivation of every nickname. We came to the same conclusion during our research of family nicknames, another specific anthroponymic category, still quite present in the Kalnik area. Having limited our field research on 12 places throughout the wide researched area, we managed to confirm 173 real family nicknames, whose designated motivational groups provided us with important sociolinguistic pieces of information. Concerning their structure, the majority of family nicknames turned out to be simple (N = 129), whereas concerning their motivation, the majority of family nicknames were of unknown motivation (N = 33). Other motivational groups were the following: a first name (N = 27), an occupation (N = 27), a family name (N = 25), a personal nickname (N = 22), a certain characteristic (N = 13), an ethnonym (N = 10), a toponym (N = 6), a certain subject (N = 6), and an animal (N = 4). All these mentioned different anthroponymic categories (first names, personal and family nicknames) can be confirmed profusely in the last anthroponymic category researched and analysed in this thesis – family names. Having employed the criterion of their minimum continuity of 100 years in the researched area, we have managed to confirm 1360 family names with centuries old continuity, since the 14th century to this very day. With this criterion we also managed to reduce a significant number of over 3000 family names with mostly no continuity, as well as to confirm those last names which had left their trace in the researched area. Of course, not all family names confirmed by this criterion are necessarily connected to the researched area, but are only detected in it. Out of 1360 confirmed family names, we succeeded in determining 189 family names which occur exclusively or mostly in the researched area, 100 family names which do not occur in contemporary anthroponymy of the area, and 97 family names which could also become extinguished in near future. Concerning their structure, the majority of all family names occur without a suffix (N = 681). All the confirmed family names were analysed according to their structure and motivation and listed in our Lexicon of family names at the end of this very thesis.


2016 ◽  
Vol 6 (1) ◽  
Author(s):  
A. Allahverdi-zadeh ◽  
J. Asgari ◽  
A.R. Amiri-Simkooei

AbstractGPS draconitic signal (351.6 ± 0.2 days) and its higher harmonics are observed at almost all IGS products such as position time series of IGS permanent stations. Orbital error and multipath are known as two possible sources of these signals. The effect of Earth shadow crossing of GPS satellites is another suspect for this signal. Up to now there is no serious attempt to investigate this dependence. AMATLAB toolbox is developed and used to determine the satellites located at the earth shadow. RINEX observation files and precise ephemeris are imported to the toolbox and a cylindrical model is used to detect the shadow regions. Data of these satellites were removed from the RINEX observation files of three IGS permanent stations (GRAZ,ONSAandWSRT) and new RINEX observation fileswere created. The time span of these data is about 11 years. The new and original fileswere then processed using precise point positioning (PPP) method to determine position time series, for further analysis. Both the original and new time series were analyzed using the least squares harmonic estimation (LS-HE) in the following steps. The 1st step is the validation of the draconitic harmonics signature in the original position time series of the three stations. The 2nd step does the same for the new time series. It confirms that the power spectrum at the draconitic signals decreases to some extent for the new time series. The difference between the original and new time series (difference between all three position quantity (X, Y and Z)) is then analyzed in the 3rd step. Signature of the draconitic harmonics is also observed to the differences. The results represent that all eight harmonics of GPS draconitic period do exist at the residuals and mainly they decrease. All of the three stations were then processed together using the multivariate LS-HE method. At the 4th step, the difference of the spectral values between the original time series and new times serieswere analyzed. Decreasing of the spectral values at most harmonics (e.g. 1st, 2nd, 4th, 6th, 7th and 8th) represents the effect of removing satellite observations at shadow of the earth on draconitic harmonics. At least, five harmonics among seven shows the amelioration of results (draconitic error reduction) after removing the earth shadowed data from RINEX raw data. The results show that the draconitic year’s component of data is in part due to eclipsing satellites.


2017 ◽  
Vol 6 (3) ◽  
pp. 85
Author(s):  
ömer önalan

In this paper we present a novel model to analyze the behavior of random asset price process under the assumption that the stock price pro-cess is governed by time-changed generalized mixed fractional Brownian motion with an inverse gamma subordinator. This model is con-structed by introducing random time changes into generalized mixed fractional Brownian motion process. In practice it has been observed that many different time series have long-range dependence property and constant time periods. Fractional Brownian motion provides a very general model for long-term dependent and anomalous diffusion regimes. Motivated by this facts in this paper we investigated the long-range dependence structure and trapping events (periods of prices stay motionless) of CSCO stock price return series. The constant time periods phenomena are modeled using an inverse gamma process as a subordinator. Proposed model include the jump behavior of price process because the gamma process is a pure jump Levy process and hence the subordinated process also has jumps so our model can be capture the random variations in volatility. To show the effectiveness of proposed model, we applied the model to calculate the price of an average arithmetic Asian call option that is written on Cisco stock. In this empirical study first the statistical properties of real financial time series is investigated and then the estimated model parameters from an observed data. The results of empirical study which is performed based on the real data indicated that the results of our model are more accuracy than the results based on traditional models.


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