We show using superposed epoch analysis (SEA) that the most energetic protons (> 60 MeV) in the n... more We show using superposed epoch analysis (SEA) that the most energetic protons (> 60 MeV) in the near-Earth interplanetary magnetic field (IMF) have a peak almost immediately (less than a day) after the peak in solar-flare index (SFI), while protons greater than 10 MeV peak one day after the SFI and protons greater than 1 MeV peak two days after the SFI. The geomagnetic indices AU,-AL, PC, Ap, and-Dst peak after two to three days in SEAs after the peak in SFI. The auroral electrojet indices AU and-AL, however, have only low peaks. In particular, the response of the eastward electrojet, AU, to SFI is negligible compared to other geomagnetic indices. The SEAs of the SFI and cosmic-ray counts (CR) show that the deepest decline in the CR intensity also follows with a 2-3-day lag the maximum of the SFI for Solar Cycles 20-24. The depths of the declines are related to the SFI strength of each cycle, i.e., the average decline is about 5% for Cycles 21 and 22, but only 3% for Cycle 24. The strongest Cycle 19, however, differs from the other cycles such that it has a double-peaked decline and lasts longer than the decline of the other cycles. The double-superposed epoch analyses show that the response of IMF Bv 2 , which is about two days, and CR to SFI are quite simultaneous, but sometimes Bv 2 may peak somewhat earlier than the decline existing in CR.
We study the solar flare index (SFI) for the Solar Cycles 18 – 24. We find that SFI has deeper Gn... more We study the solar flare index (SFI) for the Solar Cycles 18 – 24. We find that SFI has deeper Gnevyshev gap (GG) in its first principal component than other atmospheric parameters. The GG is extremely clear especially in the even cycles.The GG of the SFI appears about a half year later as a drop in the interplanetary magnetic field near the Earth and in the geomagnetic Ap-index. The instantaneous response of the magnetic field to solar flares, however, shows about two to three days after the eruption as a high, sharp peak in the cross-correlation of the SFI and Ap-index and as a lower peak in SFI vs. IMF B cross-correlation. We confirm these rapid responses using superposed-epoch analysis.The most active flare cycles during 1944 – 2020 are Cycles 19 and 21. Cycle 18 has very strong SFI days as many as Cycle 22, but it has the least nonzero SFI days in the whole interval. Interestingly, Cycle 20 can be compared to Cycles 23 and 24 in its low flare activity, although it is located be...
Evidence is presented that suggests there is a significant self-organized criticality (SOC) compo... more Evidence is presented that suggests there is a significant self-organized criticality (SOC) component in the dynamics of substorms in the magnetosphere. Observations of BBFs, fast flows, localized dipolarizations, plasma turbulence, etc. are taken to show that multiple localized reconnection sites provide the basic avalanche phenomenon in the establishment of SOC in the plasma sheet. First results are presented from a continuing plasma physical study of this avalanche process. A one-dimensional resistive MHD model of a magnetic field reversal is discussed. Resistivity, in this model, is self-consistently generated in response to the excitation of an idealized current-driven instability. When forced by convection of magnetic flux into the field reversal region, the model yields rapid magnetic field annihilation through a dynamic behavior that is shown to exhibit many of the characteristics of SOC. Over a large range of forcing strengths, the annihilation rate is shown to self-adjust to
Colloids and Surfaces A: Physicochemical and Engineering Aspects, Oct 1, 2015
We studied spreading of drops of water and dilute alcohol on multiwall carbon nanotube (MWNT) dep... more We studied spreading of drops of water and dilute alcohol on multiwall carbon nanotube (MWNT) depositions. These deposits consisted of individual arcdischarge synthesized MWNTs and irregular amorphous carbon nanoparticles on hydrophilically rendered silicon substrates. The mobile circular contact line of a spreding drop created an annular shape on the deposit, where some of the MWNTs and the amorphous nanoparticles in particular were largely depleted. The effect was strongly dependent on the hydrophilicity of the substrate. Most of the MWNTs were not only left within the annuli, but were also apparently reoriented by their interaction with the passing contact line. Our results imply the possibility of applications in quality improvement of nanotube depositions in terms of both tube orientation and cleanliness.
A detailed analysis has been made of 13 periods of 20 days of the AE data. The average correlatio... more A detailed analysis has been made of 13 periods of 20 days of the AE data. The average correlation dimension is found to be 3.4, and the calculated dimension is found to depend on the magnetospheric activity such that more active periods have smaller dimensions. This apparent correlation dimension does not, however, imply that the magnetospheric system behind the AE
Annual and Solar Rotation Periodicities In Imf Components: Evidence For Phase/frequency Modulation
EGS General Assembly Conference Abstracts, 2002
We study the annual periodicity and the solar rotation periodicity of the in‐ecliptic components ... more We study the annual periodicity and the solar rotation periodicity of the in‐ecliptic components of the interplanetary magnetic field (IMF). It is well known that the annual periodicity undergoes a phase reversal in 11 years, reflecting the 22‐year Hale cycle of the solar magnetic field. We construct a model where the annual periodicity of the IMF components is phase/frequency modulated by the Hale cycle, and show that this model can reproduce the observed properties of the annual periodicity. We find that the solar rotation periodicity depicts an analogous nodal structure and a phase reversal with a period of about 3.2 years, implying a new periodicity in the properties of the IMF. We demonstrate that, using the observed spectral width, the phase/frequency modulation model can satisfactorily explain this structure. We also note that taking into account the observed phase reversal in the solar rotation periodicity implies that the most persistent synodic solar rotation period in the in‐ecliptic IMF components is 27.6 days, i.e., somewhat longer than recently suggested.
A method based on the curvelet transform is introduced to estimate the orientation distribution f... more A method based on the curvelet transform is introduced to estimate the orientation distribution from two-dimensional images of small anisotropic particles. Orientation of fibers in paper is considered as a particular application of the method. Theoretical aspects of the suitability of this method are discussed and its efficiency is demonstrated with simulated and real images of fibrous systems. Comparison is made with two traditionally used methods of orientation analysis, and the new curvelet-based method is shown to perform better than these traditional methods.
We study the latitudinal distribution and temporal evolution of the sunspot penumbra-umbra ratio ... more We study the latitudinal distribution and temporal evolution of the sunspot penumbra-umbra ratio ($q$ q ) for the even and odd Solar Cycles 12 – 24 of RGO sunspot groups, SC21 – SC24 of Debrecen sunspot groups and Kodaikanal sunspot dataset for SC16 – SC24. We find that RGO even (odd) Cycles have $q$ q -values 5.20 (4.75), Kodaikanal even (odd) cycles have $q$ q -values 5.27 (5.43), and Debrecen cycles have $q$ q -value 5.74 on the average.We also show that $q$ q is at its lowest around the Equator of the Sun and increases towards higher latitudes having maximum values at about 10 – 25 degrees. This is understandable because smaller sunspots and groups locate nearer to the Equator and have smaller $q$ q -values than larger sunspots and groups, which maximize at about 10 – 20 degrees at both hemispheres. The error limits are very wide, and, thus, the confidence in this result is somewhat vague.For the Debrecen dataset, we find a deep valley in the temporal $q$ q -values before the mi...
We decompose the monthly cosmic-ray data, using several neutron-monitor count rates, of Cycles 19... more We decompose the monthly cosmic-ray data, using several neutron-monitor count rates, of Cycles 19 – 24 with principal component analysis (PCA). Using different cycle limits, we show that the first and second PC of cosmic-ray (CR) data explain 77 – 79% and 13 – 15% of the total variation of the Oulu CR Cycles 20 – 24 (C20 – C24), 73 – 77% and 13 – 17% of the variation of Hermanus C20 – C24, and 74 – 78% and 17 – 21% of the Climax C19 – C22, respectively. The PC1 time series of the CR Cycles 19 – 24 has only one peak in its power spectrum at the period 10.95 years, which is the average solar-cycle period for SC19 – SC24. The PC2 time series of the same cycles has a clear peak at period 21.90 (Hale cycle) and another peak at one third of that period with no peak at the solar-cycle period. We show that the PC2 of the CR is essential in explaining the differences in the intensities of the even and odd cycles of the CR. The odd cycles have a positive phase in the first half and a negative...
The homogeneous coronal data set (HCDS) of the green corona (Fe xiv) and the coronal index of sol... more The homogeneous coronal data set (HCDS) of the green corona (Fe xiv) and the coronal index of solar activity (CI) have been used to study the time–latitudinal distribution in Solar Cycles 18 – 24 and compared with similar distribution of sunspots, the magnetic fields, and the solar 10.7 cm radio flux. The most important results are: i) the distribution of coronal intensities related to the cycle maximum are different for individual cycles, ii) the poleward migration of the HCDS from mid-latitudes in each cycle exists, even in the extremely weak Cycle 24, and the same is valid for the equatorward migration, iii) the overall values of HCDS are slightly stronger for the northern hemisphere than for the southern one, iv) the distribution of the HDCS is in coincidence with the strongest photospheric magnetic fields ($B>$ B > 50 Gauss) and histograms of the sunspot groups, v) the Gnevyshev gap was confirmed with at least 95% confidence in the CI, however with different behavior for ...
Optics and Photonics for Counterterrorism, Crime Fighting, and Defence X; and Optical Materials and Biomaterials in Security and Defence Systems Technology XI, 2014
A novel method is introduced for distinguishing counterfeit banknotes from genuine samples. The m... more A novel method is introduced for distinguishing counterfeit banknotes from genuine samples. The method is based on analyzing differences in the networks of paper fibers. The main tool is a curvelet-based algorithm for measuring the distribution of overall fiber orientation and quantifying its anisotropy. The use of a couple or more appropriate parameters makes it possible to distinguish forgeries from genuine samples as concentrated point clouds in a two-or three-dimensional parameter space. Furthermore, the techniques of making watermarks is investigated by comparing genuine and counterfeit e50 banknotes. In addition, the so-called wire markings are shown to differ significantly from each other in all of investigated banknotes.
A novel method is presented for distinguishing postal stamp forgeries and counterfeit banknotes f... more A novel method is presented for distinguishing postal stamp forgeries and counterfeit banknotes from genuine samples. The method is based on analyzing differences in paper fibre networks. The main tool is a curvelet-based algorithm for measuring overall fibre orientation distribution and quantifying anisotropy. Using a couple of more appropriate parameters makes it possible to distinguish forgeries from genuine originals as concentrated point clouds in two- or three-dimensional parameter space.
A mathematical model for fibrous structures using a direction dependent scaling law is presented.... more A mathematical model for fibrous structures using a direction dependent scaling law is presented. The orientation of fibrous nets (e.g. paper) is analysed with a method based on the curvelet transform. The curvelet-based orientation analysis has been tested successfully on real data from paper samples: the major directions of fibrefibre orientation can apparently be recovered. Similar results are achieved in tests on data simulated by the new model, allowing a comparison with ground truth.
We study distributions of differences of unscaled Riemann zeta zeros, γ-γ^', at large. We sho... more We study distributions of differences of unscaled Riemann zeta zeros, γ-γ^', at large. We show, that independently of the location of the zeros, i.e., even for zeros as high as 10^23, their differences have similar statistical properties. The distributions of differences are skewed usually towards the nearest zeta zero. We show, however, that this is not always the case, but depends upon the distance and number of nearby zeros on each side of the corresponding distribution. The skewness, however, always decreases when zeta zero is crossed from left to right, i.e., in increasing direction. Furthermore, we show that the variance of distributions has local maximum or, at least, a turning point at every zeta zero, i.e., local minimum of the second derivative of the variance. In addition, it seems that the higher the zeros the more compactly the distributions of the differences are located in the skewness-kurtosis -plane. Furthermore, we show that distributions can be fitted with Joh...
We study distributions of differences of unscaled Riemann zeta zeros, γ-γ', at large. We show... more We study distributions of differences of unscaled Riemann zeta zeros, γ-γ', at large. We show, that independently of the location of the zeros, their differences have similar statistical properties. The distributions of differences are skewed towards the nearest zeta zero, have local maximum of variance and local minimum of kurtosis at or near each zeta zero. Furthermore, we show that distributions can be fitted with Johnson probability density function, despite the value of skewness or kurtosis of the distribution.
We study the evolution of continental, zonal and seasonal land temperature anomalies especially i... more We study the evolution of continental, zonal and seasonal land temperature anomalies especially in the early 20th century warming (ETCW) period, using principal component analysis (PCA) and reverse arrangement trend analysis. ETCW is significant in all other continents except for Oceania. Warming in South America is significant from the ETCW onwards, but significant recent warming started in North America and Europe only around 1990. The zonal and seasonal PC2s are both correlated with AMO index, but zonal PC3 is related to Southern oscillation index (SOI) and seasonal PC3 best correlated with wintertime El Nino (NINO34 DJF index). In the southern hemisphere, the recent warming starts first closest to the equator in the 1950s and latest in the southernmost zone in the late 1970s. In the two lowest northern zones (EQ-N24, N24-N44) the warming is significant since the ETCW, and increased warming starts in 1970s, but in two northernmost zones (N44-N64, N64-N90) the cooling after the ET...
We show using superposed epoch analysis (SEA) that the most energetic protons (> 60 MeV) in the n... more We show using superposed epoch analysis (SEA) that the most energetic protons (> 60 MeV) in the near-Earth interplanetary magnetic field (IMF) have a peak almost immediately (less than a day) after the peak in solar-flare index (SFI), while protons greater than 10 MeV peak one day after the SFI and protons greater than 1 MeV peak two days after the SFI. The geomagnetic indices AU,-AL, PC, Ap, and-Dst peak after two to three days in SEAs after the peak in SFI. The auroral electrojet indices AU and-AL, however, have only low peaks. In particular, the response of the eastward electrojet, AU, to SFI is negligible compared to other geomagnetic indices. The SEAs of the SFI and cosmic-ray counts (CR) show that the deepest decline in the CR intensity also follows with a 2-3-day lag the maximum of the SFI for Solar Cycles 20-24. The depths of the declines are related to the SFI strength of each cycle, i.e., the average decline is about 5% for Cycles 21 and 22, but only 3% for Cycle 24. The strongest Cycle 19, however, differs from the other cycles such that it has a double-peaked decline and lasts longer than the decline of the other cycles. The double-superposed epoch analyses show that the response of IMF Bv 2 , which is about two days, and CR to SFI are quite simultaneous, but sometimes Bv 2 may peak somewhat earlier than the decline existing in CR.
We study the solar flare index (SFI) for the Solar Cycles 18 – 24. We find that SFI has deeper Gn... more We study the solar flare index (SFI) for the Solar Cycles 18 – 24. We find that SFI has deeper Gnevyshev gap (GG) in its first principal component than other atmospheric parameters. The GG is extremely clear especially in the even cycles.The GG of the SFI appears about a half year later as a drop in the interplanetary magnetic field near the Earth and in the geomagnetic Ap-index. The instantaneous response of the magnetic field to solar flares, however, shows about two to three days after the eruption as a high, sharp peak in the cross-correlation of the SFI and Ap-index and as a lower peak in SFI vs. IMF B cross-correlation. We confirm these rapid responses using superposed-epoch analysis.The most active flare cycles during 1944 – 2020 are Cycles 19 and 21. Cycle 18 has very strong SFI days as many as Cycle 22, but it has the least nonzero SFI days in the whole interval. Interestingly, Cycle 20 can be compared to Cycles 23 and 24 in its low flare activity, although it is located be...
Evidence is presented that suggests there is a significant self-organized criticality (SOC) compo... more Evidence is presented that suggests there is a significant self-organized criticality (SOC) component in the dynamics of substorms in the magnetosphere. Observations of BBFs, fast flows, localized dipolarizations, plasma turbulence, etc. are taken to show that multiple localized reconnection sites provide the basic avalanche phenomenon in the establishment of SOC in the plasma sheet. First results are presented from a continuing plasma physical study of this avalanche process. A one-dimensional resistive MHD model of a magnetic field reversal is discussed. Resistivity, in this model, is self-consistently generated in response to the excitation of an idealized current-driven instability. When forced by convection of magnetic flux into the field reversal region, the model yields rapid magnetic field annihilation through a dynamic behavior that is shown to exhibit many of the characteristics of SOC. Over a large range of forcing strengths, the annihilation rate is shown to self-adjust to
Colloids and Surfaces A: Physicochemical and Engineering Aspects, Oct 1, 2015
We studied spreading of drops of water and dilute alcohol on multiwall carbon nanotube (MWNT) dep... more We studied spreading of drops of water and dilute alcohol on multiwall carbon nanotube (MWNT) depositions. These deposits consisted of individual arcdischarge synthesized MWNTs and irregular amorphous carbon nanoparticles on hydrophilically rendered silicon substrates. The mobile circular contact line of a spreding drop created an annular shape on the deposit, where some of the MWNTs and the amorphous nanoparticles in particular were largely depleted. The effect was strongly dependent on the hydrophilicity of the substrate. Most of the MWNTs were not only left within the annuli, but were also apparently reoriented by their interaction with the passing contact line. Our results imply the possibility of applications in quality improvement of nanotube depositions in terms of both tube orientation and cleanliness.
A detailed analysis has been made of 13 periods of 20 days of the AE data. The average correlatio... more A detailed analysis has been made of 13 periods of 20 days of the AE data. The average correlation dimension is found to be 3.4, and the calculated dimension is found to depend on the magnetospheric activity such that more active periods have smaller dimensions. This apparent correlation dimension does not, however, imply that the magnetospheric system behind the AE
Annual and Solar Rotation Periodicities In Imf Components: Evidence For Phase/frequency Modulation
EGS General Assembly Conference Abstracts, 2002
We study the annual periodicity and the solar rotation periodicity of the in‐ecliptic components ... more We study the annual periodicity and the solar rotation periodicity of the in‐ecliptic components of the interplanetary magnetic field (IMF). It is well known that the annual periodicity undergoes a phase reversal in 11 years, reflecting the 22‐year Hale cycle of the solar magnetic field. We construct a model where the annual periodicity of the IMF components is phase/frequency modulated by the Hale cycle, and show that this model can reproduce the observed properties of the annual periodicity. We find that the solar rotation periodicity depicts an analogous nodal structure and a phase reversal with a period of about 3.2 years, implying a new periodicity in the properties of the IMF. We demonstrate that, using the observed spectral width, the phase/frequency modulation model can satisfactorily explain this structure. We also note that taking into account the observed phase reversal in the solar rotation periodicity implies that the most persistent synodic solar rotation period in the in‐ecliptic IMF components is 27.6 days, i.e., somewhat longer than recently suggested.
A method based on the curvelet transform is introduced to estimate the orientation distribution f... more A method based on the curvelet transform is introduced to estimate the orientation distribution from two-dimensional images of small anisotropic particles. Orientation of fibers in paper is considered as a particular application of the method. Theoretical aspects of the suitability of this method are discussed and its efficiency is demonstrated with simulated and real images of fibrous systems. Comparison is made with two traditionally used methods of orientation analysis, and the new curvelet-based method is shown to perform better than these traditional methods.
We study the latitudinal distribution and temporal evolution of the sunspot penumbra-umbra ratio ... more We study the latitudinal distribution and temporal evolution of the sunspot penumbra-umbra ratio ($q$ q ) for the even and odd Solar Cycles 12 – 24 of RGO sunspot groups, SC21 – SC24 of Debrecen sunspot groups and Kodaikanal sunspot dataset for SC16 – SC24. We find that RGO even (odd) Cycles have $q$ q -values 5.20 (4.75), Kodaikanal even (odd) cycles have $q$ q -values 5.27 (5.43), and Debrecen cycles have $q$ q -value 5.74 on the average.We also show that $q$ q is at its lowest around the Equator of the Sun and increases towards higher latitudes having maximum values at about 10 – 25 degrees. This is understandable because smaller sunspots and groups locate nearer to the Equator and have smaller $q$ q -values than larger sunspots and groups, which maximize at about 10 – 20 degrees at both hemispheres. The error limits are very wide, and, thus, the confidence in this result is somewhat vague.For the Debrecen dataset, we find a deep valley in the temporal $q$ q -values before the mi...
We decompose the monthly cosmic-ray data, using several neutron-monitor count rates, of Cycles 19... more We decompose the monthly cosmic-ray data, using several neutron-monitor count rates, of Cycles 19 – 24 with principal component analysis (PCA). Using different cycle limits, we show that the first and second PC of cosmic-ray (CR) data explain 77 – 79% and 13 – 15% of the total variation of the Oulu CR Cycles 20 – 24 (C20 – C24), 73 – 77% and 13 – 17% of the variation of Hermanus C20 – C24, and 74 – 78% and 17 – 21% of the Climax C19 – C22, respectively. The PC1 time series of the CR Cycles 19 – 24 has only one peak in its power spectrum at the period 10.95 years, which is the average solar-cycle period for SC19 – SC24. The PC2 time series of the same cycles has a clear peak at period 21.90 (Hale cycle) and another peak at one third of that period with no peak at the solar-cycle period. We show that the PC2 of the CR is essential in explaining the differences in the intensities of the even and odd cycles of the CR. The odd cycles have a positive phase in the first half and a negative...
The homogeneous coronal data set (HCDS) of the green corona (Fe xiv) and the coronal index of sol... more The homogeneous coronal data set (HCDS) of the green corona (Fe xiv) and the coronal index of solar activity (CI) have been used to study the time–latitudinal distribution in Solar Cycles 18 – 24 and compared with similar distribution of sunspots, the magnetic fields, and the solar 10.7 cm radio flux. The most important results are: i) the distribution of coronal intensities related to the cycle maximum are different for individual cycles, ii) the poleward migration of the HCDS from mid-latitudes in each cycle exists, even in the extremely weak Cycle 24, and the same is valid for the equatorward migration, iii) the overall values of HCDS are slightly stronger for the northern hemisphere than for the southern one, iv) the distribution of the HDCS is in coincidence with the strongest photospheric magnetic fields ($B>$ B > 50 Gauss) and histograms of the sunspot groups, v) the Gnevyshev gap was confirmed with at least 95% confidence in the CI, however with different behavior for ...
Optics and Photonics for Counterterrorism, Crime Fighting, and Defence X; and Optical Materials and Biomaterials in Security and Defence Systems Technology XI, 2014
A novel method is introduced for distinguishing counterfeit banknotes from genuine samples. The m... more A novel method is introduced for distinguishing counterfeit banknotes from genuine samples. The method is based on analyzing differences in the networks of paper fibers. The main tool is a curvelet-based algorithm for measuring the distribution of overall fiber orientation and quantifying its anisotropy. The use of a couple or more appropriate parameters makes it possible to distinguish forgeries from genuine samples as concentrated point clouds in a two-or three-dimensional parameter space. Furthermore, the techniques of making watermarks is investigated by comparing genuine and counterfeit e50 banknotes. In addition, the so-called wire markings are shown to differ significantly from each other in all of investigated banknotes.
A novel method is presented for distinguishing postal stamp forgeries and counterfeit banknotes f... more A novel method is presented for distinguishing postal stamp forgeries and counterfeit banknotes from genuine samples. The method is based on analyzing differences in paper fibre networks. The main tool is a curvelet-based algorithm for measuring overall fibre orientation distribution and quantifying anisotropy. Using a couple of more appropriate parameters makes it possible to distinguish forgeries from genuine originals as concentrated point clouds in two- or three-dimensional parameter space.
A mathematical model for fibrous structures using a direction dependent scaling law is presented.... more A mathematical model for fibrous structures using a direction dependent scaling law is presented. The orientation of fibrous nets (e.g. paper) is analysed with a method based on the curvelet transform. The curvelet-based orientation analysis has been tested successfully on real data from paper samples: the major directions of fibrefibre orientation can apparently be recovered. Similar results are achieved in tests on data simulated by the new model, allowing a comparison with ground truth.
We study distributions of differences of unscaled Riemann zeta zeros, γ-γ^', at large. We sho... more We study distributions of differences of unscaled Riemann zeta zeros, γ-γ^', at large. We show, that independently of the location of the zeros, i.e., even for zeros as high as 10^23, their differences have similar statistical properties. The distributions of differences are skewed usually towards the nearest zeta zero. We show, however, that this is not always the case, but depends upon the distance and number of nearby zeros on each side of the corresponding distribution. The skewness, however, always decreases when zeta zero is crossed from left to right, i.e., in increasing direction. Furthermore, we show that the variance of distributions has local maximum or, at least, a turning point at every zeta zero, i.e., local minimum of the second derivative of the variance. In addition, it seems that the higher the zeros the more compactly the distributions of the differences are located in the skewness-kurtosis -plane. Furthermore, we show that distributions can be fitted with Joh...
We study distributions of differences of unscaled Riemann zeta zeros, γ-γ', at large. We show... more We study distributions of differences of unscaled Riemann zeta zeros, γ-γ', at large. We show, that independently of the location of the zeros, their differences have similar statistical properties. The distributions of differences are skewed towards the nearest zeta zero, have local maximum of variance and local minimum of kurtosis at or near each zeta zero. Furthermore, we show that distributions can be fitted with Johnson probability density function, despite the value of skewness or kurtosis of the distribution.
We study the evolution of continental, zonal and seasonal land temperature anomalies especially i... more We study the evolution of continental, zonal and seasonal land temperature anomalies especially in the early 20th century warming (ETCW) period, using principal component analysis (PCA) and reverse arrangement trend analysis. ETCW is significant in all other continents except for Oceania. Warming in South America is significant from the ETCW onwards, but significant recent warming started in North America and Europe only around 1990. The zonal and seasonal PC2s are both correlated with AMO index, but zonal PC3 is related to Southern oscillation index (SOI) and seasonal PC3 best correlated with wintertime El Nino (NINO34 DJF index). In the southern hemisphere, the recent warming starts first closest to the equator in the 1950s and latest in the southernmost zone in the late 1970s. In the two lowest northern zones (EQ-N24, N24-N44) the warming is significant since the ETCW, and increased warming starts in 1970s, but in two northernmost zones (N44-N64, N64-N90) the cooling after the ET...
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Papers by Jouni Takalo