A far field numerical model is developed to simulate jet pollution into natural rivers. Its character is to compute the velocity and pollution concentration separately. The velocity is computed by SIMPLEC algorithm i...A far field numerical model is developed to simulate jet pollution into natural rivers. Its character is to compute the velocity and pollution concentration separately. The velocity is computed by SIMPLEC algorithm in boundary fitted coordinate systems. The pollution concentration distribution is computed by developed QUAL IIm and QAIIL 2D program. The present model was applied to the Xiantao section of the Hanjiang River a tributary of Yangtze River, and Xiangjiang River. The flow field and COD distribution are in good agreement with field data.展开更多
The diurnal variability of precipitation depth over the Tibetan Plateau and its surrounding regions is investigated using nine years of Tropical Rainfall Measuring Mission （TRMM） precipitation radar （PR） measureme...The diurnal variability of precipitation depth over the Tibetan Plateau and its surrounding regions is investigated using nine years of Tropical Rainfall Measuring Mission （TRMM） precipitation radar （PR） measurements. The Tibetan Plateau, the plains area, and the East China Sea are selected as the focus regions in this study. The average precipitation depths （PD） are about 4.6 km, 5.8 km, and 5.6 km, while convective （stratiform） PDs are about 6.6 （4.5） km, 7.5 （5.7） km, and 6.0 （5.6） km over the plateau, the plains, and the ocean region, respectively. Results demonstrate a prominent PD diurnal cycle, and its diurnal phase is generally a few hours behind the surface precipitation. The spatial variation of the PD diurnal magnitude is weaker near the coastal areas than that of surface precipitation. The height of the PD diurnal peak is around 6 7 km for convective systems and 5-6 km for stratifrom systems. The dominant afternoon diurnal peak for convective PD and the flat diurnal peak for stratiform PD over the Tibetan Plateau indicate that solar diurnal forcing is the key mechanism of the PD diurnal cycle over land. In addition, the diurnal variation is obvious for shallow and deep convective systems, but not for shallow and deep stratiform systems.展开更多
The relationship between surface rain rate and depth of rain system （rain depth） over Southeast Asia is examined using 10-yr Tropical Rainfall Measuring Mission （TRMM） precipitation radar （PR） measurements. Resu...The relationship between surface rain rate and depth of rain system （rain depth） over Southeast Asia is examined using 10-yr Tropical Rainfall Measuring Mission （TRMM） precipitation radar （PR） measurements. Results show that, in general, a large surface rain rate is associated with a deep precipitating system, but a deep rain system may not always correspond with a large surface rain rate. This feature has a regional characteristic, Convective rain develops more frequently over land than over the ocean, while stratiform rain can extend to higher altitudes over the ocean than over land. A light surface rain rate has the largest probability to occur, regardless of rain depth. A convective rain system is more likely associated with a stronger surface rain rate than a stratiform rain system. Results show that precipitation systems involve complex microphysical processes. Rain depth is just one characteristic of precipitation. A linear relationship between surface rain rate and rain depth does not exist. Both deep convective and stratiform rain systems have reflectivity profiles that can be divided into three sections. The main difference in their profiles is at higher levels, from 4.5 km up to 19 km. For shallow stratiform rain systems, a two-section refiectivity profile mainly exists, while for convective systems a three-section profile is more common.展开更多
文摘A far field numerical model is developed to simulate jet pollution into natural rivers. Its character is to compute the velocity and pollution concentration separately. The velocity is computed by SIMPLEC algorithm in boundary fitted coordinate systems. The pollution concentration distribution is computed by developed QUAL IIm and QAIIL 2D program. The present model was applied to the Xiantao section of the Hanjiang River a tributary of Yangtze River, and Xiangjiang River. The flow field and COD distribution are in good agreement with field data.
基金supportedby the National Natural Science Foundation of China with research Grant Nos.40428002,40633018,and 40775058
文摘The diurnal variability of precipitation depth over the Tibetan Plateau and its surrounding regions is investigated using nine years of Tropical Rainfall Measuring Mission （TRMM） precipitation radar （PR） measurements. The Tibetan Plateau, the plains area, and the East China Sea are selected as the focus regions in this study. The average precipitation depths （PD） are about 4.6 km, 5.8 km, and 5.6 km, while convective （stratiform） PDs are about 6.6 （4.5） km, 7.5 （5.7） km, and 6.0 （5.6） km over the plateau, the plains, and the ocean region, respectively. Results demonstrate a prominent PD diurnal cycle, and its diurnal phase is generally a few hours behind the surface precipitation. The spatial variation of the PD diurnal magnitude is weaker near the coastal areas than that of surface precipitation. The height of the PD diurnal peak is around 6 7 km for convective systems and 5-6 km for stratifrom systems. The dominant afternoon diurnal peak for convective PD and the flat diurnal peak for stratiform PD over the Tibetan Plateau indicate that solar diurnal forcing is the key mechanism of the PD diurnal cycle over land. In addition, the diurnal variation is obvious for shallow and deep convective systems, but not for shallow and deep stratiform systems.
基金funded by four special grants from the National Natural Science Foundation of China (Grand Nos.41175046,41205030,40428002 and 41105028)the Special Funds for Scientific Research on Public Causes of China (Meteorology) (Grand No. GYHY200906002)
文摘The relationship between surface rain rate and depth of rain system （rain depth） over Southeast Asia is examined using 10-yr Tropical Rainfall Measuring Mission （TRMM） precipitation radar （PR） measurements. Results show that, in general, a large surface rain rate is associated with a deep precipitating system, but a deep rain system may not always correspond with a large surface rain rate. This feature has a regional characteristic, Convective rain develops more frequently over land than over the ocean, while stratiform rain can extend to higher altitudes over the ocean than over land. A light surface rain rate has the largest probability to occur, regardless of rain depth. A convective rain system is more likely associated with a stronger surface rain rate than a stratiform rain system. Results show that precipitation systems involve complex microphysical processes. Rain depth is just one characteristic of precipitation. A linear relationship between surface rain rate and rain depth does not exist. Both deep convective and stratiform rain systems have reflectivity profiles that can be divided into three sections. The main difference in their profiles is at higher levels, from 4.5 km up to 19 km. For shallow stratiform rain systems, a two-section refiectivity profile mainly exists, while for convective systems a three-section profile is more common.
