On the role of resolution and topography in the simulation of East Asia precipitation   总被引：13，自引：0，他引：13  

Xuejie Gao  Ying Xu  Zongci Zhao  J. S. Pal  F. Giorgi 《Theoretical and Applied Climatology》2006,86(1-4):173-185

Summary In this paper, we investigate the role that horizontal resolution plays in the simulation of East Asia precipitation. Two sets of numerical experiments are performed using the Regional Climate Model (RegCM2) nested in one-way mode within the CSIRO global coupled atmosphere-ocean model. In the first set we use the actual RegCM2 topography at the selected model resolutions, which are 45, 60, 90, 120, 180, 240 and 360 km. In the second set of the experiments, the same coarse CSIRO model topography is used in all simulations using the different resolutions of the first set. The results demonstrate that the simulation of East Asian precipitation improves as the horizontal resolution is increased. Moreover, it is shown that the simulations using a higher resolution along with the coarse CSIRO topography perform better than the simulations using a coarser model resolution with corresponding model topography. This suggests that over East Asia adequate spatial resolution to resolve the physical and dynamical processes is more important than topography. Lastly, the results indicate that model resolutions of 60 km or higher are needed to accurately simulate the distribution of precipitation over China and East Asia.  相似文献   

Observations of physical effects from tsunamis of December 30, 2002 at Stromboli volcano, southern Italy   总被引：1，自引：0，他引：1  

Stefano Tinti  Alessandra Maramai  Alberto Armigliato  Laura Graziani  Anna Manucci  Gianluca Pagnoni  Filippo Zaniboni 《Bulletin of Volcanology》2006,68(5):450-461

On December 30, 2002, following an intense period of activity of Stromboli volcano (south Tyrrhenian Sea, Italy), complex mass failures occurred on the northwest slope of the mountain which also involved the underwater portion of the volcanic edifice for a total volume of about 2–3×10⁷ m³. Two main landslides occurred within a time separation of 7 min, and both set tsunami waves in motion that hit the coasts of Stromboli causing injuries to three people and severe damage to buildings and structures. The tsunamis also caused damage on the island of Panarea, some 20 km to the SSE from the source. They were observed all over the Aeolian archipelago, at the island of Ustica to the west, along the northern Sicily coasts to the south as well as along the Tyrrhenian coasts of Calabria to the east and in Campania to the north. This paper presents field observations that were made in the days and weeks immediately following the events. The results of the quantitative investigations undertaken in the most affected places, namely along the coasts of Stromboli and on the island of Panarea, are reported in order to highlight the dynamics of the attacking waves and their impact on the physical environment, on the coastal structures and on the coastal residential zone. In Stromboli, the tsunami waves were most violent along the northern and northeastern coastal belt between Punta Frontone and the village of Scari, with maximum runup heights of about 11 m measured on the beach of Spiaggia Longa. Measured runups were observed to decay rapidly with distance from the source, typical of tsunami waves generated by limited-area sources such as landslides.  相似文献   

Soil erosion prediction at the basin scale using the revised universal soil loss equation (RUSLE) in a catchment of Sicily (southern Italy)   总被引：3，自引：0，他引：3  

Filippo Onori  Piero De Bonis  Sergio Grauso 《Environmental Geology》2006,50(8):1129-1140

Soil erosion by water is a serious problem in southern Italy, particularly in Sicily which is one of the Italian administrative regions prone to desertification. Soil erosion not only affects soil quality, in terms of agricultural productivity, but also reduces the availability of water in reservoirs. This study was conducted in the Comunelli catchment in south-central Sicily, to predict potential annual soil loss using the revised universal soil loss equation (RUSLE) and to test the reliability of this methodology to predict reservoirs siltation. The RUSLE factors were calculated for the catchment using survey data and rain gauge measurement data. The R-factor was calculated from daily, monthly and annual precipitation data. The K-factor was calculated from soil samples collected in May and November 2004. The LS topographic factor was calculated from a 20 m digital elevation model. The C- and P-factors, in absence of detailed data, were set to 1. The results were compared with those obtained from another soil loss estimation method based on ¹³⁷Cs and with the soil loss estimated from the sediment volume stored in the Comunelli reservoir between 1968 and 2004.  相似文献   

An analysis of regional climate change in Switzerland     

M. Beniston  M. Rebetez  F. Giorgi  M. R. Marinucci 《Theoretical and Applied Climatology》1994,49(3):135-159

Summary An analysis of daily climatological data covering the period from 1901 to 1992 for four locations in Switzerland (Zurich, Lugano, Davos, and Säntis) has been made. The study has highlighted the fact that climate change this century is characterized by increases in minimum temperatures of about 2 K, a more modest increase in maximum temperatures (in some instances a decrease of maxima in the latter part of the record), little trend in the precipitation data, and a general decrease of sunshine duration through to the mid 1980s. The interannual variability is generally large, and filtering of the data to remove high-frequency noise shows that the regional climate undergoes a series of fluctuations of between 8 and 20 years' duration. The temperature change over this century is of greater magnitude than the global temperature changes published in the literature, reflecting an amplification of the global signal in the Alpine region; warming has been most intense in the 1940s, followed by the 1980s; the cooling which intervened from the 1950s to the late 1970s was not sufficient to offset the warming in the middle of the century.Pressure statistics have been compiled as a means of providing a link between the regional-scale climatological variables and the synoptic, supra-regional scale. These statistics show that pressure also exhibits a number of decadal-scale fluctuations, with the appearance of a new and anomalous behavior in the 1980s; in this decade, pressure reaches annual average values far higher than at other times this century. The pressure field is well correlated with the North Atlantic Oscillation (NAO) Index for distinct periods of the record (1931–1950 and 1971–1990) and is almost decorrelated from the NAO Index for the other decades of the century; this is indicative of transition from one climatic régime to another, dominated by zonal flow when the correlation with the NAO Index is high. In the 1980s, when zonal flow over the North Atlantic is strong, episodes of persistent, anomalously high pressures (blocking highs) are seen to occur over Switzerland, particularly during the winter season. The difference between the zonal and non-zonal régimes is particularly marked between the decade of the 1950s and that of the 1980s.The impact of this change between the 1950s and the 1980s on a number of climatological variables has been investigated statistically in order to provide an illustration of the manner in which changes in synoptic régimes (i.e., climate change) impacts upon climate characteristics on a regional scale. The analysis shows that temperature, precipitation, snow depth, and sunshine duration are indeed sensitive to large-scale influences; not only can yearly mean changes be quantified, but also seasonal and monthly fluctuations.With 26 Figures  相似文献   

Helium in Phlegraean Fields soil gases: July 20th–26th — September 19th–25th, 1983     

S. Lombardi  M. Di Filippo  L. Zantedeschi 《Bulletin of Volcanology》1984,47(2):259-265

Two helium surveys were carried out at Phlegraean Fields in July and September 1983 aiming at locating loci of discontinuities (fractures) in the area on the basis of variations in helium concentrations following the bradyseismic crisis then in progress.  相似文献   

Neon isotope variations in Mid-Atlantic Ridge basalts     

Robert Poreda  Filippo Radicati di Brozolo 《Earth and Planetary Science Letters》1984,69(2):277-289

The isotopic composition of neon was measured for seventeen samples of submarine basalt glass from the Mid-Atlantic Ridge between 54° and 73°N. They include the Reykjanes, Kolbeinsey, and Mohns Ridge segments. Neon isotopic anomalies, relative to the atmospheric ratios, exist in both²⁰Ne/²²Ne and²¹Ne/²²Ne. A maximum excess²⁰Ne of 7% was measured in two samples from the Reykjanes Ridge. Samples with lower²⁰Ne excesses (six samples with δ²⁰Ne between 2 and 4%) from all three ridge segments, appear to result from mixing of a mantle component with a δ²⁰Ne of 7% and atmospheric neon.²¹Ne/²²Ne ratios are up to 8% above the atmospheric value, with no apparent correlation with the²⁰Ne excesses. The anomalies in²⁰Ne/²²Ne are difficult to explain by mass fractionation of an atmospheric reservoir since several of the samples have δ²⁰Ne values greater than could be produced by single-stage fractionation. Most likely, the excess²¹Ne results from nuclear reactions in the mantle source, although there is no definite correlation between the δ²¹Ne or the excess²¹Ne (cm³ STP/g) and the uranium concentration. Large variations in the observed⁴He/²⁰Ne ratio (40–12,000) remain unexplained at this time.  相似文献   

A statistical investigation of polar auroras     

Maurizio Giorgi  Giovanni P. Gregori  Carlo Valenti 《Pure and Applied Geophysics》1968,71(1):42-50

Summary The magnetosphere depends on the astronomical orientation of the geomagnetic field with respect to the solar wind. The statistical distribution of polar auroras must therefore depend on the orientation of the geomagnetic field with respect to the ecliptic plane. We have investigated this peculiar feature of auroras that we call auroral astronomical geometry. We give here some preliminary results concerning a limited set of pre-IGY auroras. The criteria that we have chosen to prepare the auroral collection are also briefly summarized. The results conform to the hypothesis of the auroral origin from the magnetospheric neutral sheet. Auroral particles are found to impinge over the earth with low angles with respect to the ecliptic plane (40°). Only in a 4-hours interval around midnight they are found to impinge with angles up to 70°. Definite evidence of these facts requires further investigation with a larger amount of data. — We have also prepared a complex code for recording the morphological features of each aurora, namely: standard information, movement. intensity, color, sunlight illumination, period of pulsation, location in the sky among stars and planets, time evolution, duration and general features of the auroral display. It is well known in fact that the auroral morphology affects auroral heights and latitudes, etc.; presumably it should also affect its astronomical geometry, which we will investigate later.Presented at the Inter-Union Symposium on Solar-Terrestrial Physics — Belgrade 1966.  相似文献   

Subsurface mass redistributions at Mount Etna (Italy) during the 1995–1996 explosive activity detected by microgravity studies     

Gennaro Budetta  Daniele Carbone  & Filippo Greco 《Geophysical Journal International》1999,138(1):77-88

Gravity changes are presented from a series of field microgravity surveys conducted at Mt Etna between August 1994 and November 1996, a period including the 1995–1996 explosive summit activity. Data were collected along a microgravity network of 69 stations at a monthly to annual sampling rate, depending on each subarray of the network.
  Results show that seasonal changes in water level within the volcano may induce gravity changes of up to 20  μgal on Etna's southern slope, and indicate that significant magma movement occurred within and below Etna's edifice between 1994 and 1996. In particular, between September 1994 and October 1995, a mass increase of 2 × 10¹⁰  kg occurred 2000  m beneath the summit craters. Between October 1995 and July 1996 this mass was lost, while another 2 × 10¹⁰  kg was injected at about 1000  m  a.s.l. into the 1989 fracture system. From the gravity data alone, it is not possible to distinguish whether the first shallow intrusion (1994–1995) was then injected laterally into the 1989 fracture, or summit activity was fed by the first shallow intrusion, while new magma entered the 1989 fracture system.
  While magma was being redistributed within the volcanic edifice, measurements along an E–W-trending profile on the southern slope of the volcano detected some 1.5 × 10¹¹  kg of magma accumulating 2–3  km below sea level between October 1995 and November 1996.  相似文献   

An earthquake precursor mobile network          下载免费PDF全文

Manana Kachakhidze  Nino Kachakhidze-Murphy  Giorgi Khazaradze  Badri Khvitia 《地震科学（英文版）》2021,34(2):168-176

It is widely known that very low frequency/low frequency (VLF/LF) radiation has been recorded prior to large earthquakes in several seismically active countries of the world. The networks employed to detect this radiation consist of stationary transmitters and receivers. However, there are reported cases of existing networks being unable to detect any electromagnetic radiation prior to large earthquakes. In this study, we determined the optimal arrangement of a mobile VLF/LF electromagnetic radiation network to ensure the detection of an upcoming earthquake precursor. We consi-dered the possible arrangements of the VLF/LF mobile network based on certain physical considerations, and deve-loped a relatively simple arrangement that is completely different from the existing stationary networks. The suggested design will significantly increase the number of detected/predicted earthquakes by using the relevant electromagnetic radiation receivers strategically placed in regions of increased tectonic and seismic activity.  相似文献   

A new hybrid procedure for the definition of seismic vulnerability in Mediterranean cross-border urban areas     

Liborio Cavaleri  Fabio Di Trapani  Marco Filippo Ferrotto 《Natural Hazards》2017,86(2):517-541

Assessment of seismic vulnerability of urban areas provides fundamental information for activities of planning and management of emergencies. The main difficulty encountered when extending vulnerability evaluations to urban contexts is the definition of a framework of assessment appropriate for the specific characteristics of the site and providing reliable results with a reasonable duration of surveys and post-processing of data. The paper proposes a new procedure merging different typologies of information recognized on the territories investigated and for this reason called “hybrid.” Knowledge of historical events influencing urban evolution and analysis of recurrent building technologies are used to evaluate the vulnerability indexes of buildings and building stocks. On the other hand, a vulnerability model is calibrated by means of experimental and numerical investigations on prototype buildings representative of the most recurrent typologies. In the final framework, the vulnerability index, calculated through simplified assessment forms, is linked to the seismic intensity expressed by the peak ground acceleration and associated with an index of damage expressing the economical loss. The procedure has been tested on the urban center of Lampedusa island (Italy) providing as the output vulnerability index maps, vulnerability curves, critical PGA maps, and estimation of the economical damage associated with different earthquake scenarios. The application of the procedure can be suitably repeated for medium-to-small urban areas, typically recurring in the Mediterranean by carrying out each time a recalibration of the vulnerability model.  相似文献