An integrated satellite precipitation estimation dataset, namely, the Climate Prediction Center morphing method (CMORPH), was used to analyze precipitation regimes across Equatorial Africa between 3<span style=&quo...An integrated satellite precipitation estimation dataset, namely, the Climate Prediction Center morphing method (CMORPH), was used to analyze precipitation regimes across Equatorial Africa between 3<span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#ffffff;"="">°</span><span><span><span style="font-family:;" "=""><span style="font-family:Verdana;">S - 1</span><span style="font-family:Verdana;"><span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#ffffff;"=""><span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#ffffff;"="">°</span></span></span><span style="font-family:Verdana;">N and 24</span><span style="font-family:Verdana;"><span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#ffffff;"=""><span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#ffffff;"="">°</span></span></span><span style="font-family:Verdana;">E - 42</span><span style="font-family:Verdana;"><span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#ffffff;"=""><span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#ffffff;"="">°</span></span></span><span style="font-family:Verdana;">E from 2000 to 2014. This region includes the Rift Valley, part of the Congo Forest, and the Lake Victoria (LV) basin, the second largest lake in the area of the world. Hovm<span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#ffffff;"=""><span style="color:#4F4F4F;font-family:-apple-system, "font-size:16px;white-space:normal;background-color:#FFFFFF;">ö</span></span>ller diagrams were obtained for all organized convective systems to estimate their spans, duration, and phase speeds. The analysis included 33,189 episodes of westward propagating convective systems. Within the study area, lake and land breezes tend to trigger convection and precipitation over LV as well as mountain-valley circulation trigger thunderstorms over the mountains east of LV and western Rift Valley. The statistics of convective systems streaks on longitude-time diagrams were obtained for yearly frequencies of starting and ending longitudes and times among other morphologic variables. Results indicate organized precipitation episodes tend to move westward across Rift valley and Congo forest with an average phase speed of 10.3 <span style="white-space:normal;font-family:Verdana;">m<span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"="">·</span>s</span><sup style="white-space:normal;"><span style="font-family:Verdana;"><span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;background-color:#f7f7f7;"=""><span style="color:#4F4F4F;font-family:-apple-system, "font-size:16px;white-space:normal;background-color:#FFFFFF;">-</span></span></span><span style="font-family:Verdana;">1</span></sup></span><sup><span style="font-family:Verdana;"></span></sup><span style="font-family:Verdana;">. More than 50% of them are triggered over LV and propagate more than 600 km at an average phase speed of 12.1 m<span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"="">·</span>s</span><sup><span style="font-family:Verdana;"><span style="white-space:normal;color:#4F4F4F;font-family:-apple-system, " font-size:16px;background-color:#f7f7f7;"=""><span style="color:#4F4F4F;font-family:-apple-system, "font-size:16px;white-space:normal;background-color:#FFFFFF;">-</span></span><span style="font-family:Verdana;white-space:normal;"></span></span><span style="font-family:Verdana;">1</span></sup><span style="font-family:Verdana;">. These convective systems tend to produce high rainfall rates hundreds of kilometers away into the Congo Forest. Half of all episodes of organized convection analyzed have phase speeds between 8 <span style="white-space:normal;font-family:Verdana;">m<span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"="">·</span>s</span><sup style="white-space:normal;"><span style="font-family:Verdana;"><span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;background-color:#f7f7f7;"=""><span style="color:#4F4F4F;font-family:-apple-system, "font-size:16px;white-space:normal;background-color:#FFFFFF;">-</span></span></span><span style="font-family:Verdana;">1</span></sup></span><sup><span style="font-family:Verdana;"></span><span style="font-family:Verdana;"></span></sup><span style="font-family:Verdana;"> and 16 <span style="white-space:normal;font-family:Verdana;">m<span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"="">·</span>s</span><sup style="white-space:normal;"><span style="font-family:Verdana;"><span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;background-color:#f7f7f7;"=""><span style="color:#4F4F4F;font-family:-apple-system, "font-size:16px;white-space:normal;background-color:#FFFFFF;">-</span></span></span><span style="font-family:Verdana;">1</span></sup></span><sup><span style="font-family:Verdana;"></span><span style="font-family:Verdana;"></span></sup><span style="font-family:Verdana;">, lasting 8 hr to 16 hr. Most precipitating systems start east of LV and west of Rift Valley in the afternoon to early morning and propagates less than 400 km. Finally, hourly precipitation accumulation and lightning density analysis indicate three preferable regions for convective initiation: 1) The mountain range east of LV;2) Midwest of LV, and;3) The Congo Forest mountain range.</span></span></span></span>展开更多
This study consists of hydrological simulations of the Muriaé river watershed with the topography-based hydrological model (TOPMODEL) and available stream gauge and rain measurements between 2009 and 2013 for two...This study consists of hydrological simulations of the Muriaé river watershed with the topography-based hydrological model (TOPMODEL) and available stream gauge and rain measurements between 2009 and 2013 for two subbasins, namely </span><i><span style="font-family:Verdana;">Carangola</span></i><span style="font-family:Verdana;"> and </span><i><span style="font-family:Verdana;">Patrocínio do Muriaé</span></i><span style="font-family:Verdana;">. The simulations were carried out with the Climate Prediction Center morphing method (CMORPH) precipitation estimates and rain gauge measurements integrated into CM- ORPH by the Statistical Objective Analysis Scheme (SOAS). TOPMODEL calibration was performed with the shuffled complex evolution (SCE-UA) method with Nash-Sutcliffe efficiency (NSE). The best overall results were obtained with CMORPH (NSE ~ 0.6) for both subbasins. The simulations with SOAS resulted in an NSE ~ 0.2. However, in an analysis of days with high- level stages, SOAS simulations resulted in a better hit rate (23%) compared to CMORPH (10%). CMORPH simulations underestimated the flows at the flood periods, which indicates the importance to use multi-sensor precipitation data. The results with TOPMODEL allow an estimate of future discharges, which allows for better planning of a flood warning system and discharge measurement schedule.展开更多
This work presents the climatology of the microphysics and the dynamics of weather systems in two coastal areas of São Paulo and the Espírito States at high spatial-temporal resolution as measured by two...This work presents the climatology of the microphysics and the dynamics of weather systems in two coastal areas of São Paulo and the Espírito States at high spatial-temporal resolution as measured by two dual Doppler weather radars during the summer and early fall of 2015. Averages and respective standard deviations of polarimetric variables, namely, reflectivity (Z), differential reflectivity (Z<sub>DR</sub>), differential phase (ϕ<sub>DP</sub>), specific differential phase (K<sub>DP</sub>), copolar correlation coefficient (ρ<sub>oHV</sub>), radial velocity (V<sub>r</sub>), and the spectral width (W) were obtained within a 240-km range on plan position indicator (PPI), constant altitude plan position indicator (CAPPI) and vertical cross-sections to analyze overall horizontal and vertical precipitation microphysics and mesoscale circulation of prevailing weather systems, and their peculiarities over coastal and oceanic, and urban and rural areas. Overall, raindrops tend to be larger over the Metropolitan area of São Paulo from the surface to up to 6 km altitude indicating more vigorous updrafts caused by the heat island effect and the local sea breeze. The vertical microphysical structure is remarkably distinct over the Metropolitan Area of São Paulo (MASP) where thunderstorms can reach 20-km altitude in summertime under sea breeze and heat island effects. On the other hand, there is a dominancy of smaller drop sizes though larger ones observed close to the surface by the coast of Espírito Santo and at the land-ocean interface influenced by the local low-level jet and oceanic-type CCN. Convective cells tend to be smaller associated with Easterlies and more organized with Westerlies. The results indicate distinct features on hydrometeor types and circulation characteristics under these different surface and boundary-layer conditions in close agreement with previous results in the literature.展开更多
文摘An integrated satellite precipitation estimation dataset, namely, the Climate Prediction Center morphing method (CMORPH), was used to analyze precipitation regimes across Equatorial Africa between 3<span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#ffffff;"="">°</span><span><span><span style="font-family:;" "=""><span style="font-family:Verdana;">S - 1</span><span style="font-family:Verdana;"><span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#ffffff;"=""><span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#ffffff;"="">°</span></span></span><span style="font-family:Verdana;">N and 24</span><span style="font-family:Verdana;"><span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#ffffff;"=""><span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#ffffff;"="">°</span></span></span><span style="font-family:Verdana;">E - 42</span><span style="font-family:Verdana;"><span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#ffffff;"=""><span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#ffffff;"="">°</span></span></span><span style="font-family:Verdana;">E from 2000 to 2014. This region includes the Rift Valley, part of the Congo Forest, and the Lake Victoria (LV) basin, the second largest lake in the area of the world. Hovm<span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#ffffff;"=""><span style="color:#4F4F4F;font-family:-apple-system, "font-size:16px;white-space:normal;background-color:#FFFFFF;">ö</span></span>ller diagrams were obtained for all organized convective systems to estimate their spans, duration, and phase speeds. The analysis included 33,189 episodes of westward propagating convective systems. Within the study area, lake and land breezes tend to trigger convection and precipitation over LV as well as mountain-valley circulation trigger thunderstorms over the mountains east of LV and western Rift Valley. The statistics of convective systems streaks on longitude-time diagrams were obtained for yearly frequencies of starting and ending longitudes and times among other morphologic variables. Results indicate organized precipitation episodes tend to move westward across Rift valley and Congo forest with an average phase speed of 10.3 <span style="white-space:normal;font-family:Verdana;">m<span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"="">·</span>s</span><sup style="white-space:normal;"><span style="font-family:Verdana;"><span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;background-color:#f7f7f7;"=""><span style="color:#4F4F4F;font-family:-apple-system, "font-size:16px;white-space:normal;background-color:#FFFFFF;">-</span></span></span><span style="font-family:Verdana;">1</span></sup></span><sup><span style="font-family:Verdana;"></span></sup><span style="font-family:Verdana;">. More than 50% of them are triggered over LV and propagate more than 600 km at an average phase speed of 12.1 m<span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"="">·</span>s</span><sup><span style="font-family:Verdana;"><span style="white-space:normal;color:#4F4F4F;font-family:-apple-system, " font-size:16px;background-color:#f7f7f7;"=""><span style="color:#4F4F4F;font-family:-apple-system, "font-size:16px;white-space:normal;background-color:#FFFFFF;">-</span></span><span style="font-family:Verdana;white-space:normal;"></span></span><span style="font-family:Verdana;">1</span></sup><span style="font-family:Verdana;">. These convective systems tend to produce high rainfall rates hundreds of kilometers away into the Congo Forest. Half of all episodes of organized convection analyzed have phase speeds between 8 <span style="white-space:normal;font-family:Verdana;">m<span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"="">·</span>s</span><sup style="white-space:normal;"><span style="font-family:Verdana;"><span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;background-color:#f7f7f7;"=""><span style="color:#4F4F4F;font-family:-apple-system, "font-size:16px;white-space:normal;background-color:#FFFFFF;">-</span></span></span><span style="font-family:Verdana;">1</span></sup></span><sup><span style="font-family:Verdana;"></span><span style="font-family:Verdana;"></span></sup><span style="font-family:Verdana;"> and 16 <span style="white-space:normal;font-family:Verdana;">m<span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;white-space:normal;background-color:#f7f7f7;"="">·</span>s</span><sup style="white-space:normal;"><span style="font-family:Verdana;"><span style="color:#4F4F4F;font-family:-apple-system, " font-size:16px;background-color:#f7f7f7;"=""><span style="color:#4F4F4F;font-family:-apple-system, "font-size:16px;white-space:normal;background-color:#FFFFFF;">-</span></span></span><span style="font-family:Verdana;">1</span></sup></span><sup><span style="font-family:Verdana;"></span><span style="font-family:Verdana;"></span></sup><span style="font-family:Verdana;">, lasting 8 hr to 16 hr. Most precipitating systems start east of LV and west of Rift Valley in the afternoon to early morning and propagates less than 400 km. Finally, hourly precipitation accumulation and lightning density analysis indicate three preferable regions for convective initiation: 1) The mountain range east of LV;2) Midwest of LV, and;3) The Congo Forest mountain range.</span></span></span></span>
文摘This study consists of hydrological simulations of the Muriaé river watershed with the topography-based hydrological model (TOPMODEL) and available stream gauge and rain measurements between 2009 and 2013 for two subbasins, namely </span><i><span style="font-family:Verdana;">Carangola</span></i><span style="font-family:Verdana;"> and </span><i><span style="font-family:Verdana;">Patrocínio do Muriaé</span></i><span style="font-family:Verdana;">. The simulations were carried out with the Climate Prediction Center morphing method (CMORPH) precipitation estimates and rain gauge measurements integrated into CM- ORPH by the Statistical Objective Analysis Scheme (SOAS). TOPMODEL calibration was performed with the shuffled complex evolution (SCE-UA) method with Nash-Sutcliffe efficiency (NSE). The best overall results were obtained with CMORPH (NSE ~ 0.6) for both subbasins. The simulations with SOAS resulted in an NSE ~ 0.2. However, in an analysis of days with high- level stages, SOAS simulations resulted in a better hit rate (23%) compared to CMORPH (10%). CMORPH simulations underestimated the flows at the flood periods, which indicates the importance to use multi-sensor precipitation data. The results with TOPMODEL allow an estimate of future discharges, which allows for better planning of a flood warning system and discharge measurement schedule.
文摘This work presents the climatology of the microphysics and the dynamics of weather systems in two coastal areas of São Paulo and the Espírito States at high spatial-temporal resolution as measured by two dual Doppler weather radars during the summer and early fall of 2015. Averages and respective standard deviations of polarimetric variables, namely, reflectivity (Z), differential reflectivity (Z<sub>DR</sub>), differential phase (ϕ<sub>DP</sub>), specific differential phase (K<sub>DP</sub>), copolar correlation coefficient (ρ<sub>oHV</sub>), radial velocity (V<sub>r</sub>), and the spectral width (W) were obtained within a 240-km range on plan position indicator (PPI), constant altitude plan position indicator (CAPPI) and vertical cross-sections to analyze overall horizontal and vertical precipitation microphysics and mesoscale circulation of prevailing weather systems, and their peculiarities over coastal and oceanic, and urban and rural areas. Overall, raindrops tend to be larger over the Metropolitan area of São Paulo from the surface to up to 6 km altitude indicating more vigorous updrafts caused by the heat island effect and the local sea breeze. The vertical microphysical structure is remarkably distinct over the Metropolitan Area of São Paulo (MASP) where thunderstorms can reach 20-km altitude in summertime under sea breeze and heat island effects. On the other hand, there is a dominancy of smaller drop sizes though larger ones observed close to the surface by the coast of Espírito Santo and at the land-ocean interface influenced by the local low-level jet and oceanic-type CCN. Convective cells tend to be smaller associated with Easterlies and more organized with Westerlies. The results indicate distinct features on hydrometeor types and circulation characteristics under these different surface and boundary-layer conditions in close agreement with previous results in the literature.