Effects of clear-cutting,meteorological, and physiological factors on evapotranspiration in the Kamabuchi experimental watershed in northern Japan     

Tayoko Kubota  Akira Kagawa  Toshio Abe  Ikuhiro Hosoda 《水文研究》2021,35(4):e14111

This study investigated the effects of clear-cutting and the meteorological and physiological factors on forest evapotranspiration (ET), by using the water-budget method in the Kamabuchi experimental watershed (KMB; 38° 56′ 21″ N, 140° 15′ 58″ E) in northern Japan. Meteorological and discharge data collected during no-snow periods (from June to October) from 1939 were used to compare ET in three sub-watersheds: No. 1, where the forest had been left undisturbed, and No. 2 and No. 3, where Cryptomeria japonica was planted after clear-cutting. Paired watershed experiments revealed that clear-cutting caused ET to decrease by approximately 100 mm yr⁻¹, and this reduction continued for more than 20 years, even after C. japonica was planted. ET fluctuated similarly across all watersheds, regardless of clear-cutting or planting. This fluctuation is mainly caused by solar radiation and temperature. Intrinsic water-use efficiency (iWUE) calculated using δ¹³C of tree-ring cellulose in C. japonica increased due to elevated atmospheric CO₂ concentration. We estimated annual carbon fixation in a single tree as the annual net photosynthesis (A). Subsequently, transpiration (E) was calculated from the relationship between iWUE and A. The results showed that A and E per tree increased as the tree grew older; however, the trees' responses to increasing c_a suppress the increase in ET. Moreover, the fluctuation of ET from the watershed was small compared to the fluctuation of P during the observation periods because the increase and decrease in E and interception loss complemented each other.  相似文献   

Estimating the nitrate concentration from the dissolved oxygen concentration and seawater temperature in the Kuroshio extension,Oyashio, and mixed water regions     

Miho Ishizu  Chiho Sukigara  Toshio Suga  Kelvin J. Richards 《Journal of Oceanography》2015,71(1):19-26

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High inorganic phosphate concentration in coral mucus and its utilization by heterotrophic bacteria in a Malaysian coral reef          下载免费PDF全文

Ryota Nakajima  Yasuaki Tanaka  Teruaki Yoshida  Tamami Fujisawa  Asami Nakayama  Yumi Fuchinoue  Bin Haji Ross Othman  Tatsuki Toda 《Marine Ecology》2015,36(3):835-841

Inorganic nutrient contents of mucus released by Acropora corals and its utilization by heterotrophic bacteria at several different hour intervals in the coral mucus were investigated at a coral reef in Malaysia. The dissolved inorganic phosphate (DIP) concentration was 135‐fold higher than in the ambient seawater, probably due to inorganic P release from the coral gut cavity. We experimentally confirmed that heterotrophic bacteria rapidly (within 8 h) consumed ca. 80% of the initial concentration of DIP derived from coral mucus. High DIP concentration in coral mucus may enhance heterotrophic bacterial production and associated carbon flow in the microbial loop of reef ecosystems.  相似文献   

Chemical and mineralogical compositions of two grains recovered from asteroid Itokawa          下载免费PDF全文

M. Ebihara  N. Shirai  S. Sekimoto  T. Nakamura  A. Tsuchiyama  J. Matsuno  T. Matsumoto  M. Tanaka  M. Abe  A. Fujimura  Y. Ishibashi  Y. Karouji  T. Mukai  T. Okada  M. Uesugi  T. Yada 《Meteoritics & planetary science》2015,50(2):243-254

Two silicate grains (RB‐QD04‐0049 and RA‐QD02‐0064, whose estimated masses are 0.050 μg and 0.048 μg, respectively) recovered from the asteroid Itokawa by the Hayabusa spacecraft were studied for their mineralogical characteristics by synchrotron X‐ray diffraction and synchrotron X‐ray microtomography and further analyzed for their bulk chemical compositions by instrumental neutron activation analysis (INAA). According to X‐ray tomography, RB‐QD004‐0049 is composed of olivine, high‐Ca pyroxene, plagioclase, Ca‐phosphate, and troilite, whereas RA‐QD002‐0064 entirely consists of olivine. INAA data are consistent with these mineral compositions except for rare earth elements (REEs). Although the grain RB‐QD004‐0049 contains measurable REEs, which seems to be consistent with the presence of Ca‐phosphate, their abundances are anomalously high. Very low abundance of Co implies less than 0.1 mass% of metals in these two grains by calculation, which is in contrast to the result for the previously analyzed grain RA‐QD02‐0049 (Ebihara et al., 2011). FeO/Sc ratios of the grains fall within the range of those for ordinary chondrite olivines, implying that these grains are extraterrestrial in origin. FeO/MnO ratios also confirm this conclusion and further suggest that the Hayabusa grains analyzed in this study are similar to material found in LL chondrites rather than CK chondrites although olivines from LL and CK chondrites have similar Fa# (molar% of Fe relative to [Fe+Mg] in olivine) (~30) to those of the Hayabusa grains including the two grains analyzed in this study.  相似文献   

Global warming trend without the contributions from decadal variability of the Arctic Oscillation   总被引：1，自引：1，他引：0  

Yuta Nagato  H.L. Tanaka 《Polar Science》2012,6(1):15-22

Climate change associated with recent global warming is most prominent in the Arctic and subarctic. The Arctic Oscillation (AO) is a dominant atmospheric phenomenon in the Northern Hemisphere. Decadal variability of surface air temperature (SAT) associated with the AO index shows high correlation with recent global warming trend. In this study, the SAT variability in the Northern Hemisphere is separated in contributions from decadal variability by the AO and remaining components.The results indicate that the decadal variability of the AO index shows high correlation with the SAT variation until 1990. The AO index and SAT variabilities show a negative trend during 1949–1969, while the trend is positive during 1969–1989. In addition, the spatial distribution pattern of the SAT linear trend during each period shows the same pattern as AO. However, while the AO index indicates a negative trend, the SAT trend is continuously positive also after 1990. This warming pattern appearing after 1990 is caused by the Arctic amplification.Although the AO has a large amplitude on local scale, the AO is almost dynamically orthogonal to the hemispheric warming component. However, the AO can be related to the decadal variability of the Arctic and subarctic temperature change through the feedbacks by climate sub-systems.  相似文献   

Capability of the penetrator seismometer system for lunar seismic event observation   总被引：2，自引：0，他引：2  

R. Yamada  I. Yamada  S. Tanaka  N. Kobayashi  Y. Ishihara  K. Yomogida  A. Fujimura 《Planetary and Space Science》2009,57(7):751-763

We developed a seismometer system for a hard landing “penetrator” probe in the course of the former Japanese LUNAR-A project to deploy new seismic stations on the Moon. The penetrator seismometer system (PSS) consists of two short-period sensor components, a two-axis gimbal mechanism for orientation, and measurement electronics. To carry out seismic observations on the Moon using the penetrator, the seismometer system has to function properly in a lunar environment after a hard landing (impact acceleration of about 8000 G), and requires a signal-to-noise ratio to detect lunar seismic events. We evaluated whether the PSS could satisfactorily observe seismic events on the Moon by investigating the frequency response, noise level, and response to ground motion of our instrument in a simulated lunar environment after a simulated impact test. Our results indicate that the newly developed seismometer system can function properly after impact and is sensitive enough to detect seismic events on the Moon. Using this PSS, new seismic data from the Moon can be obtained during future lunar missions.  相似文献   

Pingos on Earth and Mars     

Devon M. Burr  Kenneth L. Tanaka  Kenji Yoshikawa 《Planetary and Space Science》2009,57(5-6):541-555

Pingos are massive ice-cored mounds that develop through pressurized groundwater flow mechanisms. Pingos and their collapsed forms are found in periglacial and paleoperiglacial terrains on Earth, and have been hypothesized for a wide variety of locations on Mars. This literature review of pingos on Earth and Mars first summarizes the morphology of terrestrial pingos and their geologic contexts. That information is then used to asses hypothesized pingos on Mars. Pingo-like forms (PLFs) in Utopia Planitia are the most viable candidates for pingos or collapsed pingos. Other PLFs hypothesized in the literature to be pingos may be better explained with other mechanisms than those associated with terrestrial-style pingos.  相似文献   

Fast computation of Jacobian elliptic functions and incomplete elliptic integrals for constant values of elliptic parameter and elliptic characteristic     

Toshio Fukushima 《Celestial Mechanics and Dynamical Astronomy》2009,105(1-3):245-260

In order to accelerate the numerical evaluation of torque-free rotation of triaxial rigid bodies, we present a fast method to compute various kinds of elliptic functions for a series of the elliptic argument when the elliptic parameter and the elliptic characteristic are fixed. The functions we evaluate are the Jacobian elliptic functions and the incomplete elliptic integral of the second and third kinds regarded as a function of that of the first kind. The key technique is the utilization of the Maclaurin series expansion and the addition theorems with respect to the elliptic argument. The new method is around 25 times faster than the method using the incomplete elliptic integral of general kind and around 70 times faster than the method using mathematical libraries given in the latest version of Numerical Recipes.  相似文献   

An introduction to the South China Sea throughflow: Its dynamics, variability, and application for climate   总被引：9，自引：0，他引：9  

Tangdong Qu  Y. Tony Song  Toshio Yamagata 《Dynamics of Atmospheres and Oceans》2009,47(1-3):3

The South China Sea throughflow (SCSTF) involves the inflow through the Luzon strait and the outflow through the Karimata, Mindoro, and Taiwan straits. Recent studies have suggested that the SCSTF act as a heat and freshwater conveyor, playing a potentially important role in regulating the sea surface temperature pattern in the South China Sea and its adjoining tropical Indian and Pacific Oceans. In this introductory paper, we attempt to convey the progress that has recently been made in understanding the SCSTF. We first provide an overview of existing observations, theories, and simulations of the SCSTF. Then, we discuss its interaction with the Pacific western boundary current and Indonesian throughflow. Finally, we summarize issues and questions that remain to be addressed, with special reference to the SCSTF's dynamics, variability, and implication for climate.  相似文献   

Determination of the oxidation state of radiogenic Pb in natural zircon using X-ray absorption near-edge structure     

Kazuya Tanaka  Yoshio Takahashi  Kenji Horie  Hiroshi Shimizu  Takashi Murakami 《Physics and Chemistry of Minerals》2010,37(4):249-254

We examined the L_III-edge Pb X-ray absorption near-edge structure (XANES) of three natural zircon samples with different amounts of radiation doses (1.9 × 10¹⁵ to 6.8 × 10¹⁵ α-decay events/mg). The results suggest that the oxidation state of radiogenic Pb in the zircon sample with the highest radiation dose is divalent. The XANES spectra of the two other samples with lower radiation doses suggest that radiogenic Pb(II) is present, and further that some Pb may be tetravalent. This is the first work on the determination of the oxidation state of radiogenic Pb in natural zircon using XANES.  相似文献