Scientists' warning on extreme wildfire risks to water supply     

François-Nicolas Robinne  Dennis W. Hallema  Kevin D. Bladon  Mike D. Flannigan  Gabrielle Boisramé  Christian M. Bréthaut  Stefan H. Doerr  Giuliano Di Baldassarre  Louise A. Gallagher  Amanda K. Hohner  Stuart J. Khan  Alicia M. Kinoshita  Rua Mordecai  João Pedro Nunes  Petter Nyman  Cristina Santín  Gary Sheridan  Cathelijne R. Stoof  Matthew P. Thompson  James M. Waddington  Yu Wei 《水文研究》2021,35(5):e14086

2020 is the year of wildfire records. California experienced its three largest fires early in its fire season. The Pantanal, the largest wetland on the planet, burned over 20% of its surface. More than 18 million hectares of forest and bushland burned during the 2019–2020 fire season in Australia, killing 33 people, destroying nearly 2500 homes, and endangering many endemic species. The direct cost of damages is being counted in dozens of billion dollars, but the indirect costs on water-related ecosystem services and benefits could be equally expensive, with impacts lasting for decades. In Australia, the extreme precipitation (“200 mm day −1 in several location”) that interrupted the catastrophic wildfire season triggered a series of watershed effects from headwaters to areas downstream. The increased runoff and erosion from burned areas disrupted water supplies in several locations. These post-fire watershed hazards via source water contamination, flash floods, and mudslides can represent substantial, systemic long-term risks to drinking water production, aquatic life, and socio-economic activity. Scenarios similar to the recent event in Australia are now predicted to unfold in the Western USA. This is a new reality that societies will have to live with as uncharted fire activity, water crises, and widespread human footprint collide all-around of the world. Therefore, we advocate for a more proactive approach to wildfire-watershed risk governance in an effort to advance and protect water security. We also argue that there is no easy solution to reducing this risk and that investments in both green (i.e., natural) and grey (i.e., built) infrastructure will be necessary. Further, we propose strategies to combine modern data analytics with existing tools for use by water and land managers worldwide to leverage several decades worth of data and knowledge on post-fire hydrology.  相似文献   

Phytoplankton and ice-algal communities in the seasonal ice zone during January (Southern Ocean,Indian sector)     

Takahashi  Keigo D.  Makabe  Ryosuke  Takao  Shintaro  Kashiwase  Haruhiko  Moteki  Masato 《Journal of Oceanography》2022,78(5):409-424

Journal of Oceanography - In the seasonal ice zone (SIZ), sea-ice algae have been hypothesized to influence phytoplankton species composition in seawater after melting from sea ice. However,...  相似文献   

Precise estimation of pressure–temperature paths from zoned minerals using Markov random field modeling: theory and synthetic inversion     

Tatsu?KuwataniEmail author  Kenji?Nagata  Masato?Okada  Mitsuhiro?Toriumi 《Contributions to Mineralogy and Petrology》2012,163(3):547-562

The chemical zoning profile in metamorphic minerals is often used to deduce the pressure–temperature (P–T) history of rock. However, it remains difficult to restore detailed paths from zoned minerals because thermobarometric evaluation of metamorphic conditions involves several uncertainties, including measurement errors and geological noise. We propose a new stochastic framework for estimating precise P–T paths from a chemical zoning structure using the Markov random field (MRF) model, which is a type of Bayesian stochastic method that is often applied to image analysis. The continuity of pressure and temperature during mineral growth is incorporated by Gaussian Markov chains as prior probabilities in order to apply the MRF model to the P–T path inversion. The most probable P–T path can be obtained by maximizing the posterior probability of the sequential set of P and T given the observed compositions of zoned minerals. Synthetic P–T inversion tests were conducted in order to investigate the effectiveness and validity of the proposed model from zoned Mg–Fe–Ca garnet in the divariant KNCFMASH system. In the present study, the steepest descent method was implemented in order to maximize the posterior probability using the Markov chain Monte Carlo algorithm. The proposed method successfully reproduced the detailed shape of the synthetic P–T path by eliminating appropriately the statistical compositional noises without operator’s subjectivity and prior knowledge. It was also used to simultaneously evaluate the uncertainty of pressure, temperature, and mineral compositions for all measurement points. The MRF method may have potential to deal with several geological uncertainties, which cause cumbersome systematic errors, by its Bayesian approach and flexible formalism, so that it comprises potentially powerful tools for various inverse problems in petrology.  相似文献   

Inflations prior to Vulcanian eruptions and gas bursts detected by tilt observations at Semeru Volcano,Indonesia     

Takeshi Nishimura  Masato Iguchi  Ryohei Kawaguchi  Surono  Muhamad Hendrasto  Umar Rosadi 《Bulletin of Volcanology》2012,74(4):903-911

We examine the basic characteristics of inflations at Semeru Volcano, Indonesia, to clarify the pressurization process prior to two different styles of explosive eruptions: Vulcanian eruptions and gas bursts. Analysis of data obtained from tilt meters installed close to the active crater allows clarification of the common features and the differences between the two styles of eruptions. To improve the signal-to-noise ratio and to determine the mean characteristics of the inflations, we stack tilt signals obtained from eruptions of different magnitudes and evaluate the maximum amplitude of the seismic signal associated with these eruptions. Vulcanian eruptions, which explosively release large amounts of ash, are preceded by accelerating inflation about 200–300 s before the eruption, which suggests volume expansion of the gas phase. In contrast, gas bursts, which rapidly effuse water steam accompanied by explosive sounds, follow non-accelerating changes of inflation starting 20 s before each emission. Tilt amplitudes increase with the magnitude of eruptions for both eruption styles. This suggests that the volume and/or pressure of magma or gas stored in the conduit before eruptions controls the magnitude of volcanic eruptions. These results further suggest that the magnitude of eruptions can be predicted from geodetic measurements of volcano inflation.  相似文献   

Gas hydrate saturation at Site C0002, IODP Expeditions 314 and 315, in the Kumano Basin,Nankai trough     

Ayumu Miyakawa  Saneatsu Saito  Yasuhiro Yamada  Hitoshi Tomaru  Masataka Kinoshita  Takeshi Tsuji 《Island Arc》2014,23(2):142-156

The degree of gas hydrate saturation at Integrated Ocean Drilling Program (IODP) Site C0002 in the Kumano Basin, Nankai Trough, was estimated from logging‐while‐drilling logs and core samples obtained during IODP Expeditions 314 and 315. Sediment porosity data necessary for the calculation of saturation were obtained from both core samples and density logs. Two forms of the Archie equation (‘quick‐look’ and ‘standard’) were used to calculate gas hydrate saturation from two types of electrical resistivity log data (ring resistivity and bit resistivity), and a three‐phase Biot‐type equation was used to calculate gas hydrate saturation from P‐wave velocity log data. The gas hydrate saturation baseline calculated from both resistivity logs ranges from 0% to 35%, and that calculated from the P‐wave velocity log ranges from 0% to 30%. High levels of gas hydrate saturation (>60%) are present as spikes in the ring resistivity log and correspond to the presence of gas hydrate concentrations within sandy layers. At several depths, saturation values obtained from P‐wave velocity data are lower than those obtained from bit resistivity data; this discrepancy is related to the presence of free gas at these depths. Previous research has suggested that gas from deep levels in the Kumano Basin has migrated up‐dip towards the southern and seaward edge of the basin near Site C0002. The high saturation values and presence of free gas at site C0002 suggest that a large gas flux is flowing to the southern and seaward edge of the basin from a deeper and/or more landward part of the Kumano Basin, with the southern edge of the Kumano Basin (the location of site C0002) being the main area of fluid accumulation.  相似文献   

Relationship between trace elements and depositional environments in shallow sediments: a case study from Southern Kanto Plain,Central Japan     

Masato Ueshima  Takato Takemura  Takeshi Saito  Yoshiharu Ito  Shoichiro Hamamoto  Hirotaka Saito  Toshiko Komatsu 《Environmental Earth Sciences》2017,76(18):633

Underground developments such as subways and shopping facilities have been increasing in number and magnitude in the relatively shallow subsurface of many urban areas where the earth materials commonly are composed of marine sediments. Marine sediments can contain significant amounts of toxic trace elements such as arsenic, boron, and lead. Changes in the subsurface environment caused by excavation and construction in underground developments could potentially cause these toxic elements to be dissolved into pore water of the sediments, which might lead to groundwater pollution. The purpose of this study is to investigate correlations among chemical properties of marine sediments, such as pH and electrical conductivity (EC), concentrations of toxic trace elements, and stratigraphic characteristics of the sediments. We selected three sites with different stratigraphic settings in the southern Kanto Plain around the Tokyo Metropolis. We collected core samples from shallow strata at a site in the Arakawa Lowland, southern Saitama, and at two sites in the Musashino Upland, Middle Tokyo. All sites have both marine and non-marine sediments up to 50–60 m in thickness. We determined trace element concentrations in the pore water, pH, EC, and loss on ignition. The results show that (1) the marine sediments tend to have low pH, high EC, and high sulfur concentration compared to the non-marine sediments (2) the concentration of most of the soluble heavy metals vary depending on the concentration of sulfate, the pH, and the formation processes of the strata, (3) the arsenic concentration is not related to sulfur concentration but apparently to Fe and Al concentrations, (4) the boron concentration is not related to any other properties implying that the boron level is independent of and cannot be predicted by common chemical properties, and (5) for all three sites, concentrations of most of the trace elements, EC, pH, and sulfate concentration were correlated with each other. This study shows that the concentration and potential mobilization of many toxic trace elements in marine sediments could be predicted by easily measurable pore water chemical properties such as pH and EC. This could be useful for predicting and avoiding the risk of groundwater pollution during underground development projects.  相似文献   

Secular perturbations of fictitious satellites of uranus     

Hiroshi Kinoshita  Hiroshi Nakai 《Celestial Mechanics and Dynamical Astronomy》1991,52(3):293-303

Secular perturbations of fictitious satellites that are initially circular and in the equatorial plane of Uranus are discussed. Satellites located in the region where the solar perturbation is dominant become highly eccentric and inclined with respect to the equator, and have a possibility to collide with Uranus. Satellites located in the region where the oblateness perturbation is dominant keep the original eccentricity and the inclination. A scenario of a possible extinction of outer satellites of Uranus is also discussed.  相似文献   

Effects On the Nutation of the Non-Zonal Harmonics of Third Degree     

Marta Folgueira  Jean Souchay  Hiroshi Kinoshita 《Celestial Mechanics and Dynamical Astronomy》1997,69(4):373-402

In this paper, we calculate the coefficients of the nutation for a rigid Earth model due to the C _3m and S _3m (m ≠ 0) harmonics of the geopotential, starting from the Hamiltonian theory as developped by Kinoshita (1977). We show that these coefficients are far from being negligible as given the level of truncation of 0.1 μas which is necessary in the reconstruction of the tables of nutation, and also that their value is very close to that given by Bretagnon et al. (1997). This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Age of the Solomon Sea Basin from magnetic lineations     

Masato Joshima  Yoshihisa Okuda  Fumitoshi Murakami  Kiyoyuki Kishimoto  Eiichi Honza 《Geo-Marine Letters》1987,6(4):229-234

Magnetic anomalies measured in the central to western half of the Solomon Sea, when considered with other magnetic data, reveal the existence of linear patterns. Magnetic lineation anomaly models of the Cenozoic, 65 to 0 Ma, suggest that an age between 34 and 28 Ma and a half-rate spreading speed of 5.8 cm/yr for the northern flank of a former spreading center best fits our present magnetic data in the Solomon Sea Basin. Heat flow and bathymetry data support this preferred model.  相似文献   

NATURE OF PRECIPITATION AND ACTIVITY OF CUMULUS CONVECTION DURING THE 1991 MEIYU SEASON OF CHANGJIANG-HUAIHE RIVER BASIN          下载免费PDF全文

陆尔  丁一汇 《Acta Meteorologica Sinica》1998,(1)

Seasonal variability regarding the nature of precipitation and the activity of cumulus convectionduring the 1991 Meiyu season of Changjiang-Huaihe River Basin(Jianghuai)has been investigatedby calculating apparent heat source/apparent moisture sink and analyzing TBB(cloud-topblackbody radiation temperature)data.It is found that three periods of strong ascending motionduring the Meiyu season lead to three episodes of heavy rain,and the latent heat due to theprecipitation is of the sole heat source of the atmosphere.The nature of precipitation showsdistinct seasonal variability,from frontal precipitation of the first episode to the extremely strongconvective precipitation of the third episode.TBB field of East Asia may well reflect not only theintensity of convection and rainfall,but also the movement of rain belt and convection belt.In thewhole Meiyu season.convection belt mainly stays in Jianghuai.but may shift within the domain ofEast Asia.Its locating in Jianghuai or not determines the maintenance or break of Meiyu.In thethird episode,the narrow convection belt over Jianghuai is mainly caused by southwest monsoonwhich takes moist and convective atmosphere from tropical ocean.  相似文献