Influence of climatography on rainfall thresholds for initiation of debris-flows on the California coast [abstract]

EXTRACT (SEE PDF FOR FULL ABSTRACT): Since 1986, the U.S. Geological Survey and National Weather Service have operated a warning system for debris flows triggered by severe rainstorms in the San Francisco Bay region. The NWS tracks storm systems as they approach the region, forecasts precipitation, and observes rainfall with a network of radiotelemetered rain gauges (ALERT). The USGS also monitors ALERT data and compares the observed and forecast rainfall to thresholds for debris-flow initiation. Both groups jointly assess debris-flow hazards and issue public advisories when rainfall conditions reach or approach critical levels.

In-plane critical current density measurements of straight and curved tracks in RABiTS-MOD coated conductors

Depending on the temperature and the magnitude and orientation of an external magnetic field, the critical current density, J c , of a coated conductor can be limited either by the properties of the grain boundaries or by those of the grains. In order to ascertain what governs J c under different conditions, we have measured straight and curved tracks, patterned into RABiTS-MOD samples, while a magnetic field was swept in the plane of the films. Significantly different results were obtained at different field and temperature ranges, which we were able to attribute to J c being limited by either grain boundaries or grains.

Water-soluble part of the aerosol in the dust storm season - evidence of the mixing between mineral and pollution aerosols

IEECAS SKLLQG

Temperature annealing of tracks induced by ion irradiation of graphite

Highly oriented pyrolytic graphite (HOPG) samples were irradiated by Xe ions of initial kinetic energy of 3 MeV/u. The irradiations were performed at temperatures of 500 and 800 K. Scanning tunneling microscopy (STM) images show that the tracks occasionally have elongated structures under high-temperature irradiation. The track creation yield at 800 K is by three orders of magnitude smaller compared to that obtained during room-temperature irradiation. STM and Raman spectra show that amorphization occurs in graphite samples irradiated at 500 K to higher fluences, but not at 800 K. The obtained experimental results clearly reveal that the irradiation under high temperature causes track annealing.

Simulating a typhoon storm surge in the East Sea of China using a coupled model

A coupled numerical model with a 2' x 2' resolution grid has been developed and used to simulate five typical typhoon storm surges (5612, 7413, 7910, 8114, and 9711) in the East Sea of China. Three main driving forces have been considered in this coupled model: wave radiation stress, combined wave-current bottom shear stress and wave-state-dependent surface wind stress. This model has then been compared with in situ measurements of the storm set-up. The effect of different driving force components on the total storm surge has also been investigated. This study has found that the coupled model with high resolution is capable of simulating the five typical typhoons better than the uncoupled models, and that the wave-dependent surface wind stress plays an important role in typhoon storm surge-wave coupling in this area and can increase the storm set-up by 1 m. The study of the five typhoon cases has shown that the general coupling effects could increase storm set-up by 20-32%. Thus, it is suggested that to predict typhoon storm surges in the East Sea of China, a storm surge-wave coupled model be adopted. (C) 2008 National Natural Science Foundation of China and Chinese Academy of Sciences. Published by Elsevier Limited and Science in China Press. All rights reserved.

An analysis of the recent severe storm surge disaster events in China

The economic loss caused by the storm surge disasters is much higher than that caused by any other marine disaster in China, the loss from the severe storm surge disaster being the highest. Statistics show that there were 62 typhoon landings over the east-southeast coast of China since 1990, three of which, occurring in 1992, 1994 and 1997, respectively, caused the most severe damage. The direct economic losses due to these events are 9.3, 17.0 and 30 billion yuan (RMB, or about 1.7, 2.6 and 3.8 billion USD, respectively), which is much greater than the loss of 5.5 billion yuan (RMB) on an average every year during the 1989-1991 period. This paper makes a comparative analysis of the damage caused by the three events and presents an overview of progress of precautions against storm surge disaster in China. The suggested counter measures to mitigate the loss from the severe storm surge disasters in China is as follows: (1) Raise the whole society awareness of precaution against severe storm surge disaster; (2) Work out a new plan for building sea walls; (3) Improve and perfect the available warning and disaster relief command system; (4) Develop the insurance service in order to promptly mitigate the loss caused by severe storm surge disaster event.

Effects of winds, tides and storm surges on ocean surface waves in the Sea of Japan

Ocean surface waves are strongly forced by high wind conditions associated with winter storms in the Sea of Japan. They are also modulated by tides and storm surges. The effects of the variability in surface wind forcing, tides and storm surges on the waves are investigated using a wave model, a high-resolution atmospheric mesoscale model and a hydrodynamic ocean circulation model. Five month-long wave model simulations are inducted to examine the sensitivity of ocean waves to various wind forcing fields, tides and storm surges during January 1997. Compared with observed mean wave parameters, results indicate that the high frequency variability in the surface wind filed has very great effect on wave simulation. Tides and storm surges have a significant impact on the waves in nearshores of the Tsushima-kaihyo, but not for other regions in the Sea of Japan. High spatial and temporal resolution and good quality surface wind products will be crucial for the prediction of surface waves in the JES and other marginal seas, especially near the coastal regions.