Multi-Wavelength Observations of an Unusual Impulsive Flare Associated with Cme   总被引：1，自引：0，他引：1  

Wahab?UddinEmail author  Rajmal?Jain  Keiji?Yoshimura  Ramesh?Chandra  T.?Sakao  T.?Kosugi  Anita?Joshi  M.?R.?Despande 《Solar physics》2004,225(2):325-336

We present the results of a detailed analysis of multi-wavelength observations of a very impulsive solar flare 1B/M6.7, which occurred on 10 March, 2001 in NOAA AR 9368 (N27 W42). The observations show that the flare is very impulsive with a very hard spectrum in HXR that reveal that non-thermal emission was most dominant. On the other hand, this flare also produced a type II radio burst and coronal mass ejections (CME), which are not general characteristics for impulsive flares. In H we observed bright mass ejecta (BME) followed by dark mass ejecta (DME). Based on the consistency of the onset times and directions of BME and CME, we conclude that these two phenomena are closely associated. It is inferred that the energy build-up took place due to photospheric reconnection between emerging positive parasitic polarity and predominant negative polarity, which resulted as a consequence of flux cancellation. The shear increased to >80 due to further emergence of positive parasitic polarity causing strongly enhanced cancellation of flux. It appears that such enhanced magnetic flux cancellation in a strongly sheared region triggered the impulsive flare.  相似文献   

Thermal consequences of the formation of a slab window beneath the Mid-Cretaceous southwest Japan arc: A 2-D numerical analysis   总被引：1，自引：0，他引：1  

Takamoto  Okudaira  Yoshiko  Yoshitake † 《Island Arc》2004,13(4):520-532

Abstract   The development of voluminous granitic magmatism and widespread high-grade metamorphism in Mid-Cretaceous southwest Japan have been explained by the subduction of a spreading ridge (Kula–Pacific or Farallon–Izanagi plate boundaries) beneath the Eurasian continent and the formation of a slab window. In the present study, the thermal consequences of the formation of a slab window beneath a continental margin are evaluated through a 2-D numerical simulation. The model results are evaluated by comparison with the Mid-Cretaceous geology of southwest Japan. Of particular interest are the absence of an amphibolite- to granulite-facies metamorphic belt near the Wadati–Benioff plane, and significant melting of the lower crustal-mafic rocks sufficient to form a large amount of granitic magma. Because none of the model results simultaneously satisfied these two geological interpretations, it is suggested that subduction of plate boundaries in Mid-Cretaceous southwest Japan was not associated with the opening of a slab window. According to previous studies, and the results of the present study, two different tectonic scenarios could reasonably explain the geological interpretations for Mid-Cretaceous southwest Japan: (i) The spreading ridge did not subduct beneath the Eurasian continent, but was located off the continental margin, implying the continuous subduction of very young oceanic lithosphere; (ii) ridge subduction beneath the continental margin occurred after active spreading had ceased. Consequently, in both tectonic scenarios, the subduction of plate boundaries at the Mid-Cretaceous southwest Japan was not associated with a slab window, but very young (hot) oceanic lithosphere.  相似文献   

A long-enduring multi-source burst at 17 GHz and its relation to a type IVm-dm burst with spectral fine features     

Takeo Kosugi 《Solar physics》1982,75(1-2):293-304

A proton-event-associated microwave burst occurred on November 10, 1978 and was observed with the 17 GHz interferometer at Nobeyama. The burst had a very broad extent of about 4.5 arc and consisted of at least four separate sources. The time evolutions of the individual sources were almost independent of each other. We suggest that the sources are fallen into two distinct types as follows: (i) The two-ribbon-associated sources are characterized by the source expansion in size and the relatively flat microwave spectrum, both of which can be explained by thermal emission from hot condensed plasma in the magnetic arcades whose legs are seen as the two-ribbon H flare, and (ii) the spot-related sources are characterized by the high polarization degree with a compact unipolar structure, the rapid time variation, and the inverted-U shape microwave spectrum. The intimate relation of the latter sources to the evolution of the associated type IV_m-dm burst with spectral fine features is also discussed.  相似文献   

Decadal variability of Subtropical Mode Water subduction and its impact on biogeochemistry     

Eitarou Oka  Bo Qiu  Yusuke Takatani  Kazutaka Enyo  Daisuke Sasano  Naohiro Kosugi  Masao Ishii  Toshiya Nakano  Toshio Suga 《Journal of Oceanography》2015,71(4):389-400

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Inter‐annual variations and factors controlling evapotranspiration in a temperate Japanese cypress forest          下载免费PDF全文

Kenji Tsuruta  Yoshiko Kosugi  Satoru Takanashi  Makoto Tani 《水文研究》2016,30(26):5012-5026

This study was undertaken to evaluate the effects of climatic variability on inter‐annual variations in each component of evapotranspiration (ET) and the total ET in a temperate coniferous forest in Japan. We conducted eddy covariance flux and meteorological measurements for 7 years and parameterized a one‐dimensional multi‐layer biosphere‐atmosphere model (Kosugi et al., 2006 ) that partitions ET to transpiration (Tr), wet‐canopy evaporation (E_wet), and soil evaporation (E_soil). The model was validated with the observed flux data. Using the model, the components of ET were estimated for the 7 years. Annual precipitation, ET, Tr, E_wet, and E_soil over the 7 years were 1536 ± 334 mm, 752 ± 29 mm, 425 ± 37 mm, 219 ± 34 mm, and 108 ± 10 mm, respectively. The maximum inter‐annual fluctuation of observed ET was 64 mm with a coefficient of variance (CV) of 2.7%, in contrast to relatively large year‐to‐year variations in annual rainfall (CV = 20.1%). Tr was related to the vapour pressure deficit, incoming radiation, and air temperature with relatively small inter‐annual variations (CV = 8.2%). E_soil (CV = 8.6%) was related mainly to the vapour pressure deficit. E_wet was related to precipitation with large inter‐annual variations (CV = 14.3%) because of the variability in precipitation. The variations in E_wet were counterbalanced by the variations in Tr and E_soil, producing the small inter‐annual variations in total ET. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

Cross-Validation of Open-Path and Closed-Path Eddy-Covariance Techniques for Observing Methane Fluxes     

Hiroki Iwata  Yoshiko Kosugi  Keisuke Ono  Masayoshi Mano  Ayaka Sakabe  Akira Miyata  Kenshi Takahashi 《Boundary-Layer Meteorology》2014,151(1):95-118

Methane ( ${\mathrm {CH}}_{4}$ ) fluxes observed with the eddy-covariance technique using an open-path ${\mathrm {CH}}_{4}$ analyzer and a closed-path ${\mathrm {CH}}_{4}$ analyzer in a rice paddy field were evaluated with an emphasis on the flux correction methodology. A comparison of the fluxes obtained by the analyzers revealed that both the open-path and closed-path techniques were reliable, provided that appropriate corrections were applied. For the open-path approach, the influence of fluctuations in air density and the line shape variation in laser absorption spectroscopy (hereafter, spectroscopic effect) was significant, and the relative importance of these corrections would increase when observing small ${\mathrm {CH}}_{4}$ fluxes. A new procedure proposed by Li-Cor Inc. enabled us to accurately adjust for these effects. The high-frequency loss of the open-path ${\mathrm {CH}}_{4}$ analyzer was relatively large (11 % of the uncorrected covariance) at an observation height of 2.5 m above the canopy owing to its longer physical path length, and this correction should be carefully applied before correcting for the influence of fluctuations in air density and the spectroscopic effect. Uncorrected ${\mathrm {CH}}_{4}$ fluxes observed with the closed-path analyzer were substantially underestimated (37 %) due to high-frequency loss because an undersized pump was used in the observation. Both the bandpass and transfer function approaches successfully corrected this flux loss. Careful determination of the bandpass frequency range or the transfer function and the cospectral model is required for the accurate calculation of ${\mathrm {CH}}_{4}$ fluxes with the closed-path technique.  相似文献   

Application of a coil‐type TDR probe for measuring the volumetric water content in weathered granitic bedrock     

Shin'ya Katsura  Ken'ichirou Kosugi  Takahisa Mizuyama 《水文研究》2008,22(6):750-763

As a first step toward describing water flow processes in bedrock, a coil‐type time domain reflectometry (TDR) probe capable of measuring volumetric water content, θ, in weathered bedrock at three depths was prepared. Because the coil‐type TDR probe is large in diameter (19 mm), it can be installed even in highly weathered bedrock more easily and appropriately than conventional TDR probes that consists of two or three rods of small diameter (5‐8 mm). The probe calibrations suggest that the values measured by the probe are very sensitive to changes in θ. Using the calibrated probe together with commercially available profile soil moisture sensors, the θ profile was monitored for 1 year. Even rainfall events with relatively small cumulative rainfall of 15 mm increased the bedrock θ, and the increments were comparable to those in the soil. After the end of the rainfall events, the bedrock θ displayed a more rapid drop than the soil, and varied little during the period of no rainfall. The water storage showed similar tendencies. These observations suggest that the bedrock θ is controlled by clearly distinguishable macropores and micropores within the bedrock. It is concluded that the coil‐type TDR probe is very effective in determining θ in weathered bedrock, and that bedrock, conventionally defined by conducting cone penetration tests and treated as impermeable, does conduct and hold substantial amounts of water, and therefore contribute greatly to hydrological processes in headwater catchments. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

A pair of behind-the-limb solar flares of 1984 May 21     

Kosugi  Takeo 《Solar physics》1982,113(1-2):295-298

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Source characteristics of main and post-burst-increase phases of solar bursts at 17 GHz     

Takeo Kosugi  Keizo Kai  Takashi Suzuki 《Solar physics》1983,87(2):373-390

Twenty four solar bursts of peak fluxes above 50 sfu are analyzed which were observed with the 17 GHz interferometer at Nobeyama during the period from 1978 September to 1979 December. Source characteristics and their temporal evolutions are investigated on a statistical basis with high time resolutions up to 0.8 s. Use of a model-fitting technique recently developed by Kosugi (1982) is made to derive both the position of centroid and size (～ FWHM) of burst source with an uncertainty of a few arc sec. The results of this study are the following:

1. Two different phases in the burst, that is to say, the main phase and the post-burst-increase (PBI) phase, are distinguished clearly not only by the morphological difference of flux time profile, but also by the differences of brightness temperature (10⁷-?10⁹ K vs 10⁵–10⁷ K), circular polarization degree (0–50% vs 0–10%), and size (?5–25″ vs 10–70″). There is no definite correlation between the peak fluxes in the two phases.
2. The majority of the selected bursts (21 of 24) show in the main phase source characteristics of the impulsive burst. The total flux varies rapidly (characteristic time scale defined by FWHM ? 100 s), often associated with the rapid shift of position and the rapid change of polarization degree. The source height of the impulsive source is lower than that of the PBI source. On the other hand, the type IV_μ source, seen in three events, shows a gradual variation and the source ascends to a height of ～ 40 000 km above the photosphere.
3. In the PBI phase, the expansion and ascension of the source occur in general (21 of 23 for the former and 12 of 15 for the latter). The velocities of both the movements are of the order of 5 km s^?1.

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Potential of Oil Palm Trunk Sap as a Novel Inexpensive Renewable Carbon Feedstock for Polyhydroxyalkanoate Biosynthesis and as a Bacterial Growth Medium     

Bhadravathi Eswara Lokesh  Zubaidah Aimi Abdul Hamid  Takamitsu Arai  Akihiko Kosugi  Yoshinori Murata  Rokiah Hashim  Othman Sulaiman  Yutaka Mori  Kumar Sudesh 《洁净——土壤、空气、水》2012,40(3):310-317

Utilization of cheap renewable carbon feedstock for polyhydroxyalkanoate (PHA) production not only brings down its production cost but also ensures sustainability. The scope of this study was to evaluate the potential of sap extracted from felled oil palm trunk (OPT) as a novel inexpensive renewable carbon source for PHA production. OPT sap was found to be nutritionally rich and contained various fermentable sugars (5.5% w/v) as its major constituent. Termite gut isolate, Bacillus megaterium MC1 grew profoundly in mineral medium with OPT sap as carbon source and a cell density of 10.9 g/L was attained after 16 h of cultivation in shake flask cultures. A maximum poly‐3‐hydroxybutyrate [P(3HB)] content (% cell dry weight; CDW) of 30 wt% and a P(3HB) concentration of 3.28 g/L was recorded. Additionally, OPT sap extracted from younger tree trunks with prolonged storage had higher sugar content (10.8% w/v) and, when used as a growth medium without the addition of any nutrients, supported bacterial growth comparable to commercially available media.  相似文献