Diurnal Variation Of Intensity Research Articles

Initiations of Mesoscale Convective Systems in the Middle Reaches of the Yangtze River Basin Based on FY‐4A Satellite Data: Statistical Characteristics and Environmental Conditions

AbstractBased on the brightness temperature observed by the Fengyun‐4A satellite, eight hundred mesoscale convective systems (MCSs) are identified in the middle reaches of the Yangtze River Basin during the warm seasons (April–September) of 2018–2021, and these MCSs are categorized into the quasistationary (QS) type and the outward‐moving (OM; i.e., moving beyond the source region) type. Afterward, the initiations of the MCSs are backward tracked using a hybrid method of areal overlapping and optical flow. Then, the main features of QS‐MCSs and OM‐MCSs and their respective synoptic circulations and environmental parameters are analyzed. The QS‐MCSs primarily occur in July and August and are mainly initiated in the afternoon. The OM‐MCSs mostly occur in June and July with two initiation peaks at noon and late night, respectively. The QS‐MCSs are mainly initiated in mountainous areas. In contrast, the OM‐MCSs are mainly initiated in plain areas. Compared to the OM‐MCSs, the QS‐MCSs show notable diurnal variation in intensity and develop more rapidly. Circulations of a total of 285 days (without direct influences from tropical cyclones) are objectively classified into three patterns by using the k‐means algorithm. Pattern‐I, which is closely related to low‐level jets, shows the most similar features to those of typical Mei‐yu fronts, and it acts as the most favorable circulation type for MCS initiations. Pattern‐II is dominated by northwesterlies, with a relatively stable layer in the low‐level troposphere. Pattern‐III features a dry‐adiabatic or even a superadiabatic layer that contributes to decreasing the layer stability.

Evaluation of Hourly Precipitation Characteristics from a Global Reanalysis and Variable-Resolution Global Model over the Tibetan Plateau by Using a Satellite-Gauge Merged Rainfall Product

High-resolution meteorological datasets are urgently needed for understanding the hydrological cycle of the Tibetan Plateau (TP), where ground-based meteorological stations are sparse. Rapid advances in remote sensing create possibilities to represent spatiotemporal properties of precipitation at a high resolution. In this study, the hourly precipitation characteristics over the TP from two gridded precipitation products, one from global reanalysis (the fifth generation of the European Center for Medium-Range Weather Forecasts atmospheric reanalysis of the global climate; ERA5) and the other is simulated by Global-to-Regional Integrated forecast SysTem (GRIST) global nonhydrostatic model, are compared against satellite-gauge merged precipitation analysis (China Merged Precipitation Analysis; CMPA) from 27 July to 31 August 2014, and a satellite-retrieved precipitation estimate from the Integrated Multi-satellitE Retrievals for the Global Precipitation Measurement (IMERG) is also evolved. Two aspects are mainly focused on: the spatial distribution and the elevation dependence of hourly precipitation characteristics (including precipitation amount, frequency, intensity, diurnal variations, and frequency–intensity structure). Results indicate that: (1) The precipitation amount, frequency, and intensity of CMPA and IMERG decrease with altitude in the Yarlung Tsangpo river valley (YTRV), but increase at first and then decrease with altitude (except for intensity) in the eastern periphery of TP (EPTP). ERA5 performed well on the variation of precipitation amount with altitude (especially in EPTP), but poorly on the frequency and intensity. GRIST is the antithesis of ERA5, but they all overestimate (underestimate) the frequency (intensity) at all heights; (2) With increasing altitude, the diurnal phase of precipitation of CMPA and IMERG shifted from night to evening in the two sub-regions. IMERG’s diurnal phase is 1 to 3 h earlier than CMPA’s, and the discrepancy decreases (increases) as the altitude increases in YTRV (EPTP). The diurnal phase of precipitation amount and frequency in ERA5 and GRIST is significantly earlier than CMPA, and the frequency peaks around midday except in the basin. GRIST’s simulation of the diurnal variation in intensity at various altitudes is consistent with CMPA; (3) ERA5 and GRIST overestimate (underestimate) the frequency of weak (intense) precipitation, with ERA5’s deviance being the most severe. The deviations increased with altitude. These findings provide intensive metrics to evaluate precipitation in complex terrain and are helpful for deepening the understanding of simulated biases for further improving performance in high-resolution simulation.

A Scoping Review of the Diurnal Variation in the Intensity of Neuropathic Pain.

Recent studies have suggested that neuropathic pain exhibits a daily diurnal pattern, with peak levels usually occurring in the late afternoon to evening and the trough in the morning hours, although literature on this topic has been sparse. This scoping review examines current evidence on the chronobiology of neuropathic pain both in animal models and in humans with neuropathic pain. A literature search was conducted in major medical databases for relevant articles on the chronobiology of neuropathic pain both in animal models and in humans with neuropathic pain. Data extracted included details of specific animal models or specific neuropathic pain conditions in humans, methods and timing of assessing pain severity, and specific findings of diurnal variation in pain intensity or its surrogate markers. Thirteen animal and eight human studies published between 1976 and 2020 were included in the analysis. Seven of the 13 animal studies reported specific diurnal variation in pain intensity, with five of the seven studies reporting a trend toward increased sensitivity to mechanical allodynia or thermal hyperalgesia in the late light to dark phase. All eight studies in human subjects reported a diurnal variation in the intensity of neuropathic pain, where there was an increase in pain intensity through the day with peaks in the late evening and early night hours. Studies included in this review demonstrated a diurnal variation in the pattern of neuropathic pain that is distinct from the pattern for nociceptive pain. These findings have implications for potential therapeutic strategies for neuropathic pain.

The diurnal cycle of water ice on comet 67P/Churyumov-Gerasimenko.

Observations of cometary nuclei have revealed a very limited amount of surface water ice, which is insufficient to explain the observed water outgassing. This was clearly demonstrated on comet 9P/Tempel 1, where the dust jets (driven by volatiles) were only partially correlated with the exposed ice regions. The observations of 67P/Churyumov-Gerasimenko have revealed that activity has a diurnal variation in intensity arising from changing insolation conditions. It was previously concluded that water vapour was generated in ice-rich subsurface layers with a transport mechanism linked to solar illumination, but that has not hitherto been observed. Periodic condensations of water vapour very close to, or on, the surface were suggested to explain short-lived outbursts seen near sunrise on comet 9P/Tempel 1. Here we report observations of water ice on the surface of comet 67P/Churyumov-Gerasimenko, appearing and disappearing in a cyclic pattern that follows local illumination conditions, providing a source of localized activity. This water cycle appears to be an important process in the evolution of the comet, leading to cyclical modification of the relative abundance of water ice on its surface.

Diurnal variation of tension-type headache intensity and exacerbation: An investigation using computerized ecological momentary assessment

BackgroundsTension-type headache is a common psychosomatic disease. However, diurnal variation of headache is yet to be clarified, perhaps due to the lack of an appropriate method to investigate it. Like other painful diseases, it would be helpful to know if there is diurnal variation in tension-type headaches, both for managing headaches and understanding their pathophysiology. The aim of this study was to determine if there is diurnal variation in the intensity and exacerbation of tension-type headache.MethodsPatients (N = 31) with tension-type headache recorded for one week their momentary headache intensity several times a day and their acute headache exacerbations using a watch-type computer as an electronic diary (computerized ecological momentary assessment). Multilevel modeling was used to test the effects of time of day on momentary headache intensity and on the occurrence of acute exacerbations.ResultsA significant diurnal variation in momentary headache intensity was shown (P = 0.0005), with the weakest headaches in the morning and a peak in the late afternoon. A between-individual difference in the diurnal pattern was suggested. On-demand medication use was associated with a different diurnal pattern (P = 0.025), suggesting that headache intensity decreases earlier in the evening in subjects who used on-demand medication, while headache subtype, prophylactic medication use, and sex were not associated with the difference. The occurrence of acute headache exacerbation also showed a significant diurnal variation, with a peak after noon (P = 0.0015).ConclusionsTension-type headache was shown to have a significant diurnal variation. The relation to pathophysiology and psychosocial aspects needs to be further explored.

Spectral UV and visible irradiance measurements in the Barents Sea and Svalbard

Using a single monochromator, spectral measurements of solar irradiances of the UV and visible spectral ranges have been carried out during the midnight sun period in Arctic regions. Diurnal intensity variations are similar throughout the whole spectral region. Spectral ratios of the regions are obtained, and strong diurnal variations of the spectral ratios caused by the ozone layer are documented. The UVB region is mostly affected by the ozone layer. With UVB as the numerator in the spectral ratios the maxima of the spectral ratios occur at midday, because then the optical path of the UVB through the ozone layer is shortest. With UVA as the numerator hardly any diurnal variation between this range and visible blue occurs, mainly because of the small influence of ozone attenuation in these wavelength ranges. The influence of weather has much less influence on the spectral ratios than on the irradiances.

Ground observation of the O2(0-1) atmospheric band at 8645 Å and the [OI] 5577-Å line

A correlation study is made of the diurnal intensity changes of the O2 (0–1) atmospheric band at 8645 A and the [OI] 5577-A line, which are observed every 160 s from the ground level by a tilting filter photometer; the photometer, of which the optics consist of three aspheric lenses, is equipped with a cooled photomultiplier RCA-C31034A having a small GaAs photocathode. Simultaneous observation of the O2 (0–1) atmospheric band at 8645 A and the [OI] 5577-A line has indicated an excellent correlation in their diurnal intensity variations.

Diurnal variations in intensity of symptoms in patients of different diagnostic groups.

Consecutive patients, regardless of diagnostic group, upon admission to the Department of Psychiatry, University of Umea, were asked to fill in a special form about diurnal variation in their symptomatology and sleep disturbances. Three trained psychiatrists separately reviewed the records and completed a second form comprising information about diagnosis and certain background factors. Among the background factors only age and ongoing antidepressive medication were found to be of importance. In the study no strong consistency in the symptom complex of early awakening, experience of symptomatology as worst in the morning, and a feeling of relief in the afternoon was found. However, the experience of symptomatology as a whole, anxiety and inhibition as being worst in the morning is significantly more common in patients with unipolar and bipolar affective disorders but is also common in all diagnostic subgroups and seems in no way to be specific for depressive disorders. Furthermore, the phenomenon of diurnal variation of symptomatology was not found to be of diagnostic help and should be employed very cautiously as a basis in pathogenic consideration.

Diurnal intensity variation of low-energy electrons observed near the polar cap

Electron flux and energy spectrum measurements near polar cap investigated for diurnal intensity variations

Observation of the O I 5577 A nightglow at Christchurch, New Zealand

The O I 5577 A emission from the night sky has been observed at Christchurch, New Zealand, during the period May 1962 to May 1964. Diurnal intensity variations are found to show a regular pattern only during a limited part of the year. Annual variations are distinct and appear to be seasonally coincident with variations at a similar latitude in the northern hemisphere. The influences of ultraviolet solar flux and of dynamic motions of the upper atmosphere are considered.

The modulation of galactic cosmic rays in the interplanetary medium

The anisotropic diffusion of cosmic rays in the interplanetary medium is discussed with the assumption that the fluctuating component of the magnetic field produces a scattering effect which can be described by a simple mean free path treatment. The results of this discussion are applied to a plausible model of the interplanetary medium with the aim of providing a basis for the understanding of the processes causing the more important modulations of the galactic cosmic ray intensity. It is suggested that a gradient of the cosmic ray density exists, and that this plays a significant role in producing the solar cycle and 27-day modulation effects; in addition, the associated cosmic ray pressure gradient might affect the size of the cavity resulting from the interaction between the solar wind and the interstellar medium. Since the gradient could be present even at sunspot minimum it is possible that the energy density of cosmic rays in the galaxy is larger than the maximum value observed at the Earth, and hence this value should be regarded only as a lower limit. The main contribution to the solar diurnal variation of the cosmic ray intensity is suggested to be due to co-rotation of the cosmic rays with the Sun. However above a certain energy, which varies through the solar cycle, the galactic cosmic rays appear to be unaffected by the roughness of the interplanetary magnetic field, thus any streaming which occurs at these higher energies should cause a sidereal diurnal variation of the intensity.

A Solar Anisotropy in Cosmic Radiation, viewed from a Terrestrial Frame of Reference

IT is generally recognized that a solar anisotropy in the primary cosmic radiation must be responsible for at least part of the observed terrestrial daily variation of intensity, although it seems that the exact nature of this contribution is not yet clear. However, Rao, McCracken and Venkatesan1 have recently presented a method of determining the characteristics of a daily variation of this type. Their method takes into consideration the influence of the Earth's magnetic field and in particular they emphasize the part played by the asymptotic cones of acceptance of cosmic ray detectors. Consequently, using experimental values of the daily variation of neutron intensity averaged over the year 1958, they have been able to postulate a type of anisotropy which appears to account for the complex manner in which the amplitude and phase of the first harmonic of the daily variation depends on the geographical location of the detector. However, it would perhaps be truer to say that they predict that if the Earth's atmosphere and its magnetic field were removed the annual mean diurnal variation of intensity observed at the Earth's surface would have the following characteristics : (1) the diurnal variation would be independent of rigidity in the range 1–200 GV; (2) the amplitude would vary as the cosine of geographic latitude and the time of maximum would be in the direction 85° to the east of the Earth–Sun line; (3) the maximum amplitude, observed with narrow-angle detectors at the equator, would be 0.4 per cent of the average primary flux. It is proposed to describe here the co-ordinate transformations which relate these important characteristics to those of a selar anisotropy specified in the frame of reference in which its orientation is fixed.

Theoretical calculation of the solar diurnal variation of the cosmic ray intensity

By formulating an expression for the anisotropy of the primary cosmic ray intensity, the expected solar diurnal variation of the intensity of the nucleonic component of the cosmic radiation at sea level is calculated at various geomagnetic latitudes and longitudes for the following cases: (a) the anisotropy is produced outside the terrestrial magnetic field (extra-terrestrial origin), and (b) the anisotropy is produced inside the terrestrial magnetic field (terrestrial origin). In this calculation, the orientational difference between the earth’s rotational and the geomagnetic dipole axes is considered. The present expression for the anisotropy,Δf, contains three parameters,m, n andP i . The parameter,m, determines the rigidity dependence ofΔf in the expression,Δf ∝P −m . The parameter,n, determines the directional dependence ofΔf in momentum space with respect to the plane parallel to the geomagnetic or geographic equator in the expressionΔf ∝ (cosθ) n , whereθ is the angle between the plane and the direction mentioned above.P i is a definite value of rigidity, for rigidities smaller than whichΔf is zero. This expression for the anisotropy could easily be utilized in terms of any description of the model of production of the anisotropy by the appropriate choice of these three parameters. It is also possible to determine the most suitable values of these parameters by the comparison of the calculated and observed diurnal variations. The geographic local time of the maximum intensity shows a geomagnetic longitudinal dependence for both terrestrial and extra-terrestrial origins. On the other hand, the amplitude shows a longitudinal dependence at latitudes higher than 50°, only for the extra-terrestrial origin. At latitudes lower than 50°, there is no significant difference between the diurnal variations expected from the terrestrial and extra-terrestrial origins. The altitude correction factors of the diurnal variation of the nucleonic component are obtained. These factors are nearly independent of the geomagnetic longitude of the observational station.

Typhoon Sarah, 19561

Typhoon Sarah, 1956, the first of the season, was unusual in several respects. First, Sarah formed in a tropical depression that first became a closed circulation less than a hundred miles from the equator. Second, Sarah showed a marked diurnal variation in intensity after reaching a maximum of intensity on the second day as a typhoon. Third, besides the diurnal variation there were two periods of intensification and weakening. Fourth, the cyclone retrograded to the east-southeast several hundred miles parallel to its previous track. The diurnal variation of Typhoon Sarah appears to have its origin in the arrival of short intense lines of convergence at the eye. The arrival of these lines of convergence at the eye furnished the energy that gave the typhoon a pulsating characteristic.

The characteristic size of airglow cells

Evidence is presented for the existence of discrete 5577 airglow cells in the upper atmosphere. Independent analyses are based on 1. (a) the comparison of diurnal intensity variations in different parts of the sky and 2. (b) the measurement of intensity gradients on airglow isophote maps. The numerical estimation of cell size is complicated by the fact that a single cell is, in general, larger than the region observable at a given location. The typical airglow cell for the 12 nights of the study has a diameter of approximately 2500 km.

Diurnal Variation in the Occurrence of ‘Dawn Chorus’

IN the audio-frequency range, a phenomenon called ‘dawn chorus’, which is characterized by a multitude of rising tones, is frequently observed. Other investigators1,2 have noted that this phenomenon exhibits a pronounced diurnal variation of intensity, with the maximum occurring during the early morning hours, and the name ‘dawn chorus’ has been derived on this basis. The observations of ‘dawn chorus’ reported here were made between January 1 and July 2, 1956, at College, Alaska, with equipment sensitive to frequencies between 1 to 10 kc./s. During this interval, the equipment was in operation on 116 days. ‘Dawn chorus’ was found to be present in 224 of the 2,784 one-minute hourly observing periods. The diurnal variation in the frequency of occurrence of ‘dawn chorus’ is illustrated in Fig. 1, which represents a histogram of the number of times ‘dawn chorus’ was found to be present during the one-minute recording interval for each of the twenty-four hours of the day.

Solar Magnetic Moment and Diurnal Variation in Intensity of Cosmic Radiation

The effect of the earth's magnetic field upon the orbits of primary cosmic-ray particles is computed in detail for the special case of those particles arriving vertically anywhere on the earth's surface. A procedure is evolved for taking this deflection in conjunction with the previous deflection in the magnetic field of the sun, and thereby calculating for any given cosmic-ray energy spectrum an expected diurnal variation in total cosmic-ray intensity. Examples of this procedure are given for an inverse power spectrum applied to two different magnitudes of the solar magnetic moment. The sample calculations are made for several latitudes of observation, and the expected diurnal variation is then studied as a function of the solar magnetic moment and of the energy spectrum. The phase of the variation is found to be very sensitive to the solar moment, and so it is hoped that a successful experimental determination of the diurnal variation will settle the question of the existence and magnitude of a permanent solar magnetic moment.

Galactic Rotation and the Intensity of Cosmic Radiation at the Geomagnetic Equator

The angle of deflection experienced by a primary cosmic particle moving in the plane of the geomagnetic equator is calculated for different energies and the result used to find the diurnal variation in the intensity of cosmic rays arriving vertically at the geomagnetic equator. If it is assumed that the number of primaries varies inversely as the cube of their energy, the calculation shows that there should be a diurnal variation in the vertical intensity of 0.17 percent, if all primaries are positive, with a maximum at 13 hr. 20 min. sidereal time. With a ratio of three positive to one negative primary, and the same distribution law, the amplitude of the diurnal variation should be 0.1 percent with a maximum at 12 hr. 30 min. sidereal time, while if the primary radiation as a whole is neutral (one positive particle to each negative) the amplitude should be 0.06 percent with maximum at 8 hr. 40 min. sidereal time. If the number of primaries is an exponentially decreasing function of their energy, the amplitude of the diurnal variation should be 0.24 percent with maximum at 18 hr. sidereal time, assuming all primaries are positive; if the primary radiation is neutral the amplitude should be 0.19 percent and the maximum should occur at 20 hr. 40 min. sidereal time. The expected diurnal variations for several values of the lower limiting energy are also discussed.

The diurnal variation of the intensity of wireless waves reflected from the ionosphere

An account is given of the diurnal variation of the relative intensity of waves returned from the ionized regions of the upper atmosphere as observed over the early morning period from about 2 a.m. until about 9 a.m. The relative intensity is taken as the ratio of the intensity of the downcoming wave to that of the ground wave. The influence on the intensity of electron-limitation and of absorption-limitation is discussed, in the light of theoretical ionization curves given by Chapman. The experimental observations described show that the magneto-ionic doubling of the echo, which has been observed by Appleton and Builder for the F region, occurs also for the E region. The doublet echo for this region is observed only for a short period of the morning, owing to the fact that the extraordinary ray is very soon totally absorbed.

Societies and Academies

LONDONPhysical Society, November 3. MABY D. WALLER: Vibrating properties of metals at different temperatures. Since the damping of the vibrations is mainly due to internal friction or solid viscosity, it is greatly altered either by previous heat or mechanical treatment and by impurities. On account of the large variations of the vibrating properties with temperature, it will be possible to obtain, by observation of irregularities in these variations, much interesting information regarding the state of metals and alloys at different temperatures. MABY D. WALLER: Production of sounds from heated metals by contact with ice and other substances. The conditions are described under which soft notes may be produced from heated metal bars brought into contact with ice and a number of other substances. These substances must either sublime or boil or decompose with the evolution of gas, at temperatures for which the metal to be excited still retains adequate vibrating properties. P. C. MAHANTI: The band spectrum of barium oxide. New measurements of the bands of barium oxide have been made from moderate-dispersion and high-dispersion spectrograms. The band-head data of the early investigations have been extended in the red region as far as X 8000. The bands lying between X 8000 and X 4300 have been assigned to a single system. F. W. G. WHITE: Diurnal variation of the intensity of wireless waves reflected from the ionosphere. An account is given of the diurnal variation of the relative intensity of waves returned from the ionised regions of the upper atmosphere as observed over the early morning period from about 2 a.m. until about 9 a.m. The relative intensity is taken as the ratio of the intensity of the downcoming wave to that of the ground wave. The influence on the intensity of electron-limitation and of absorption limitation is discussed, in the light of theoretical ionisation curves given by Chapman. The experimental observations described show that the magneto-ionic doubling of the echo, which has been observed by Appleton and Builder for the F region, occurs also for the E region. J. A. RATCLIFFE and E. L. C. WHITE: Automatic records of wireless waves reflected from the ionosphere. The records extend over a period of fourteen months. They indicate that the region below the F region may be triply stratified and consist of the intermediate region (effective height approximately 120-180 km.), the E region (effective height approximately 100-120 km.), and the e region with an effective height which is always nearly 105 km., within ± 5 km. The e region is intermittent in its occurrence, and is identified with the ‘nocturnal E region’ mentioned in previous papers. The temporal variations of the ionisation in these three regions is discussed.