Using the Advanced Research WRF (ARW WRF) model and the Gridpoint Statistical Interpolation (GSI) three-dimensional variational analysis (3DVAR) system,the impact of assimilating ATOVS (Advanced TIROS Operational Vert...Using the Advanced Research WRF (ARW WRF) model and the Gridpoint Statistical Interpolation (GSI) three-dimensional variational analysis (3DVAR) system,the impact of assimilating ATOVS (Advanced TIROS Operational Vertical Sounder) radiance through the prototype Community Radiative Transfer Model (pCRTM) is evaluated on the forecasting of a heavy rainstorm occurring over the central Guangdong province in the southeast of China on 20-21 June 2005. A pair of comparison experiments (NODA and DA) for this case is conducted with multiple configurations,including nesting domains with 4-km and 12-km grid distances. The results showed that by changing the initial condition through data assimilation,a modified divergence and moisture field with the structure of dipoles has been added to the axis of the rainband with a southwest-northeast orientation. When more moisture carried by a southwesterly low level jet (LLJ) was converged into the northeast portion of the rainband around the observatory station of Longmen,the amplitude of moisture static energy (MSE) increased substantially at low levels much more than at middle levels,resulting in the enlarging of differences in MSE between 500 hPa and 850 hPa; the atmosphere became more unstable. Consequently,the convective rainfall increased in the northeast part of the province around the Longmen station,which was consistent with the observed distribution of rainfall.展开更多
The characteristics of spring precipitation and water vapor transport in South China were analyzed by using observational data and the National Centers for Environmental Prediction (NCEP) reanalysis data. The results ...The characteristics of spring precipitation and water vapor transport in South China were analyzed by using observational data and the National Centers for Environmental Prediction (NCEP) reanalysis data. The results show that, during the spring, each component of the water cycle (precipitation, wind field, specific humidity, water vapor transport, etc.) in South China exhibits a notable interdecadal variability. An abrupt increase in spring precipitation occurred in the early 1970s. During the dry period from 1958 to 1971, a water vapor flux divergence (positive divQ) existed in South China, which may have led to the deficiency in rainfall. However, during the wet period from 1973 to 1989, there was a remarkable water vapor flux convergence (negative divQ) in South China, which may have resulted in the higher rainfall. The interdecadal variability of water vapor transport is closely related to the interdecadal variability of wind fields, although the interdecadal variability of specific humidity also plays a role to some extent, and the interdecadal variability of the zonal water vapor transport contributes much more to the interdecadal variability of spring precipitation than the meridional water vapor transport.展开更多
The wave Coriolis-Stokes-Force-modified ocean momentum equations are reviewed in this paper and the wave Stokes transport is pointed out to be part of the ocean circulations. Using the European Centre for Medium-Range...The wave Coriolis-Stokes-Force-modified ocean momentum equations are reviewed in this paper and the wave Stokes transport is pointed out to be part of the ocean circulations. Using the European Centre for Medium-Range Weather Forecasts 40-year reanalysis data(ERA-40 data) and the Simple Ocean Data Assimilation(SODA) version 2.2.4 data, the magnitude of this transport is compared with that of wind-driven Sverdrup transport and a 5-to-10-precent contribution by the wave Stokes transport is found. Both transports are stronger in boreal winter than in summers. The wave effect can be either contribution or cancellation in different seasons. Examination with Kuroshio transport verifies similar seasonal variations. The clarification of the efficient wave boundary condition helps to understand the role of waves in mass transport. It acts as surface wind stress and can be functional down to the bottom of the ageostrophic layer. The pumping velocities resulting from wave-induced stress are zonally distributed and are significant in relatively high latitudes. Further work will focus on the model performance of the wave-stress-changed-boundary and the role of swells in the eastern part of the oceans.展开更多
The Zhangjiakou-Penglai fault zone lies in the northern part of North China Plain and extends along the Zhangjiakou-Huailai-Sanhe-Tianjin-Bohai Sea-Penglai-Yantai-North Huanghai Sea line, it is about 900 km long and s...The Zhangjiakou-Penglai fault zone lies in the northern part of North China Plain and extends along the Zhangjiakou-Huailai-Sanhe-Tianjin-Bohai Sea-Penglai-Yantai-North Huanghai Sea line, it is about 900 km long and some 250-km wide in a northwest direction. The 1679 Sanhe-Pinggu M 8.0 and the 1976 Tangshan M7.8 earthquakes occurred in the fault zone. In this paper an analysis of Gutenberg- Richter’s empirical relation and time process of historic and recent earthquakes along the eastern and western segments of the fault zone separated by the 117°line indicates that they obey a Poison process and, hence, a calculation from it yields a cumulative probability of strong earthquake occurrence along the two segments before 2010, i. e. the probability of M6.0 earthquake occurrence is 0.80 along the eastern segment and the probability of M7. 0 earthquake occurrence is 0.76 along the western segment of the fault zone.展开更多
China is the country with the most earthquakes and the most serious hazards from continental earthquakes in the world. During the 1960s and 1970s, a series of strong earthquakes attacked the cities and counties in Chi...China is the country with the most earthquakes and the most serious hazards from continental earthquakes in the world. During the 1960s and 1970s, a series of strong earthquakes attacked the cities and counties in China causing great damage and many casualties. The most striking one was the Tangshan earthquake ( M S7 8) in July 1976, in which over 240,000 people died and a large industrial city was leveled. Public demand for earthquake forecasting surged after this disaster. From the mid-1960s, systemic research on earthquake forecasting has evolved throughout the country. In this paper the main advances in earthquake prediction research in China have been summarized.展开更多
基金National Natural Science Foundation of China (NSFC) General Program (40775058)National Special Research Project for Non-profit Industry (GYHY200706014)
文摘Using the Advanced Research WRF (ARW WRF) model and the Gridpoint Statistical Interpolation (GSI) three-dimensional variational analysis (3DVAR) system,the impact of assimilating ATOVS (Advanced TIROS Operational Vertical Sounder) radiance through the prototype Community Radiative Transfer Model (pCRTM) is evaluated on the forecasting of a heavy rainstorm occurring over the central Guangdong province in the southeast of China on 20-21 June 2005. A pair of comparison experiments (NODA and DA) for this case is conducted with multiple configurations,including nesting domains with 4-km and 12-km grid distances. The results showed that by changing the initial condition through data assimilation,a modified divergence and moisture field with the structure of dipoles has been added to the axis of the rainband with a southwest-northeast orientation. When more moisture carried by a southwesterly low level jet (LLJ) was converged into the northeast portion of the rainband around the observatory station of Longmen,the amplitude of moisture static energy (MSE) increased substantially at low levels much more than at middle levels,resulting in the enlarging of differences in MSE between 500 hPa and 850 hPa; the atmosphere became more unstable. Consequently,the convective rainfall increased in the northeast part of the province around the Longmen station,which was consistent with the observed distribution of rainfall.
基金supported by the National Basic Research Program of China (Grant No. 2009CB421406)the National Key Technologies R&D Program of China (Grant No. 2007BAC03A00)
文摘The characteristics of spring precipitation and water vapor transport in South China were analyzed by using observational data and the National Centers for Environmental Prediction (NCEP) reanalysis data. The results show that, during the spring, each component of the water cycle (precipitation, wind field, specific humidity, water vapor transport, etc.) in South China exhibits a notable interdecadal variability. An abrupt increase in spring precipitation occurred in the early 1970s. During the dry period from 1958 to 1971, a water vapor flux divergence (positive divQ) existed in South China, which may have led to the deficiency in rainfall. However, during the wet period from 1973 to 1989, there was a remarkable water vapor flux convergence (negative divQ) in South China, which may have resulted in the higher rainfall. The interdecadal variability of water vapor transport is closely related to the interdecadal variability of wind fields, although the interdecadal variability of specific humidity also plays a role to some extent, and the interdecadal variability of the zonal water vapor transport contributes much more to the interdecadal variability of spring precipitation than the meridional water vapor transport.
基金funded by the National Science Foundation of China (40976005 and 40930844)
文摘The wave Coriolis-Stokes-Force-modified ocean momentum equations are reviewed in this paper and the wave Stokes transport is pointed out to be part of the ocean circulations. Using the European Centre for Medium-Range Weather Forecasts 40-year reanalysis data(ERA-40 data) and the Simple Ocean Data Assimilation(SODA) version 2.2.4 data, the magnitude of this transport is compared with that of wind-driven Sverdrup transport and a 5-to-10-precent contribution by the wave Stokes transport is found. Both transports are stronger in boreal winter than in summers. The wave effect can be either contribution or cancellation in different seasons. Examination with Kuroshio transport verifies similar seasonal variations. The clarification of the efficient wave boundary condition helps to understand the role of waves in mass transport. It acts as surface wind stress and can be functional down to the bottom of the ageostrophic layer. The pumping velocities resulting from wave-induced stress are zonally distributed and are significant in relatively high latitudes. Further work will focus on the model performance of the wave-stress-changed-boundary and the role of swells in the eastern part of the oceans.
基金the project of " Mechanism for Continental Strong Earthquakes and Their Prediction" , one of the projects in the National Basic Scientific Research and Development Program,grant No.G1998040706.
文摘The Zhangjiakou-Penglai fault zone lies in the northern part of North China Plain and extends along the Zhangjiakou-Huailai-Sanhe-Tianjin-Bohai Sea-Penglai-Yantai-North Huanghai Sea line, it is about 900 km long and some 250-km wide in a northwest direction. The 1679 Sanhe-Pinggu M 8.0 and the 1976 Tangshan M7.8 earthquakes occurred in the fault zone. In this paper an analysis of Gutenberg- Richter’s empirical relation and time process of historic and recent earthquakes along the eastern and western segments of the fault zone separated by the 117°line indicates that they obey a Poison process and, hence, a calculation from it yields a cumulative probability of strong earthquake occurrence along the two segments before 2010, i. e. the probability of M6.0 earthquake occurrence is 0.80 along the eastern segment and the probability of M7. 0 earthquake occurrence is 0.76 along the western segment of the fault zone.
文摘China is the country with the most earthquakes and the most serious hazards from continental earthquakes in the world. During the 1960s and 1970s, a series of strong earthquakes attacked the cities and counties in China causing great damage and many casualties. The most striking one was the Tangshan earthquake ( M S7 8) in July 1976, in which over 240,000 people died and a large industrial city was leveled. Public demand for earthquake forecasting surged after this disaster. From the mid-1960s, systemic research on earthquake forecasting has evolved throughout the country. In this paper the main advances in earthquake prediction research in China have been summarized.
