利用中尺度数值预报(Weather Research and Forecast,WRF)模式,针对2018年3月17日05—17时(北京时)北京地区的一次降雪过程模拟分析了城市化对降雪的主要影响机制。结果表明,城市化使得北京五环以内降雪量减少,降雨量增加,这主要是由于...利用中尺度数值预报(Weather Research and Forecast,WRF)模式,针对2018年3月17日05—17时(北京时)北京地区的一次降雪过程模拟分析了城市化对降雪的主要影响机制。结果表明,城市化使得北京五环以内降雪量减少,降雨量增加,这主要是由于城市化低层增温效应加强了雪的融化过程,产生混合型降水,距离市中心越近越容易发生混合型降水。城市化对降雪的总降水量和降水的时、空分布也存在一定的影响。降水初期,城市化造成的“城市干热岛”效应不利于水汽的水平和垂直输送,不利于云的形成,地面总降水量减小。随着降水过程的发展,部分冰相粒子融化,使近地面水汽增多,“城市热岛效应”的热力抬升作用有利于水汽的垂直输送和云的发展,部分云滴或水汽抬升进入云中,增强冷云过程,使雪和霰粒子含量增大,地面总降水量增加。城市化产生的“城市效应”对低层大气温度和云微物理过程产生影响,而云微物理过程的非绝热过程反过来又影响低层大气温度和大气层结,影响能量和水汽输送,进而对云和地面降水产生影响。展开更多
In this study, a 47-day regional climate simulation of the heavy rainfall in the Yangtze-Huai River Basin during the summer of 2003 was conducted using the Weather Research and Forecast （WRY） model. The simulation r...In this study, a 47-day regional climate simulation of the heavy rainfall in the Yangtze-Huai River Basin during the summer of 2003 was conducted using the Weather Research and Forecast （WRY） model. The simulation reproduces reasonably well the evolution of the rainfall during the study period＇s three successive rainy phases, especially the frequent heavy rainfall events occurring in the Huai River Basin. The model captures the major rainfall peak observed by the monitoring stations in the morning. Another peak appears later than that shown by the observations. In addition, the simulation realistically captures not only the evolution of the low-level winds but also the characteristics of their diurnal variation. The strong southwesterly （low-level jet, LLJ） wind speed increases beginning in the early evening and reaches a peak in the morning; it then gradually decreases until the afternoon. The intense LLJ forms a strong convergent circulation pattern in the early morning along the Yangtze-Huai River Basin. This pattern partly explains the rainfall peak observed at this time. This study furnishes a basis for the further analysis of the mechanisms of evolution of the LLJ and for the further study of the interactions between the LLJ and rainfall.展开更多
[Objective] The aim was to analyze characters of solar energy in photo- voltaic power stations in Shandong Province. [Method] The models of total solar radiation and scattered radiation were determined, and solar ener...[Objective] The aim was to analyze characters of solar energy in photo- voltaic power stations in Shandong Province. [Method] The models of total solar radiation and scattered radiation were determined, and solar energy resources in pho-tovoltaic power stations were evaluated based on illumination in horizontal plane and cloud data in 123 counties or cities and observed information in Jinan, Fushan and Juxian in 1988-2008. [Result] Solar energy in northern regions in Shandong proved most abundant, which is suitable for photovoltaic power generation; the optimal angle of tilt of photovoltaic array was at 35°, decreasing by 2°-3° compared with local latitude. Total solar radiation received by the slope with optimal angle of tilt exceeded 1 600 kw.h/（m2.a）, increasing by 16% compared with horizontal planes. The maximal irradiance concluded by WRF in different regions tended to be volatile in 1 020-1 060 W/m2. [Conclusion] The research provides references for construction of photovoltaic power stations in Shandong Province.展开更多
为了更好地预报重庆地区暴雨发生的时间和落区,利用重庆地区基于GPS得到的GPS-PWV(Precipitable Water Vapor)资料结合WRF数值模拟对2012年一次暴雨过程进行综合分析,分析此次过程中重庆地区GPS-PWV的变化特征、不稳定能量以及动力抬升...为了更好地预报重庆地区暴雨发生的时间和落区,利用重庆地区基于GPS得到的GPS-PWV(Precipitable Water Vapor)资料结合WRF数值模拟对2012年一次暴雨过程进行综合分析,分析此次过程中重庆地区GPS-PWV的变化特征、不稳定能量以及动力抬升条件与降水的关系。研究结果表明:此次过程在降水之前有18小时到35小时的水汽聚集过程,在接近水汽通道的迎风坡面降水量转化率较高。综合分析不稳定能量和水汽通量散度的变化结合GPS-PWV提供的水汽场能够更好地预报降水发生的时间和落区。展开更多
土地利用和土地覆盖变化(Land Use and Land Cover Chang,LUCC)通过影响局地陆面过程及陆气相互作用进而影响局地天气和气候。为探究LUCC产品对陆气相互作用的影响,本文采用了三套LUCC产品,包括USGS、Landsat和MODIS,模拟研究不同LUCC...土地利用和土地覆盖变化(Land Use and Land Cover Chang,LUCC)通过影响局地陆面过程及陆气相互作用进而影响局地天气和气候。为探究LUCC产品对陆气相互作用的影响,本文采用了三套LUCC产品,包括USGS、Landsat和MODIS,模拟研究不同LUCC产品对华东地区土壤和近地面温度、湿度的影响。结果表明,不同LUCC产品的土地利用类型差异主要在城市、农田和以草地、森林为主的自然植被。与USGS产品相比,Landsat和MODIS产品的城市和森林面积分别增加了2%和15%以上,农田面积则减少了17%左右。模拟结果表明,Landsat和MODIS产品的城市面积增加导致该区域的土壤温度和湿度增加,感热通量分别增加了28.1 W·m^(-2)、68.3 W·m^(-2),潜热通量分别减少了28.3 W·m^(-2)、81 W·m^(-2),这使得2 m气温增加了1.5℃左右,相对湿度减小了约9%。USGS产品中的农田和草地在Landsat和MODIS中改变为森林也使得土壤温度、湿度和近地面能量通量、温度和湿度的空间分布随之产生变化,但相比于城市面积改变导致的变化较为复杂。此外,不同LUCC产品之间的城市面积变化对土壤温度、湿度和近地面能量通量、温度和湿度的影响要大于农田和自然植被变化产生的影响。最后,对比三个试验模拟的土壤温度、土壤湿度、2 m气温和相对湿度结果与GLDAS(the Global Land Data Assimilation System)或站点观测资料的相关性、均方根误差、平均偏差和认同指数可以发现,使用更准确、细致的Landsat产品的模式对近地面气象条件的模拟性能要优于USGS和MODIS产品模拟结果。展开更多
The simulations of a heat wave occurring in southern Yangtze-Huaihe valley and southern China during late July,2003 were conducted to examine the sensitivity of simulated surface air temperature(SAT) to different land...The simulations of a heat wave occurring in southern Yangtze-Huaihe valley and southern China during late July,2003 were conducted to examine the sensitivity of simulated surface air temperature(SAT) to different land surface schemes(LSSs) using the Weather Research and Forecasting Model(WRF) Version 2.2 in the short-range mode for 24-h integrations.Initial and boundary conditions employed a National Centers for Environmental Prediction(NCEP) analysis.The results showed that,overall,simulated high-temperature weather is sensitive to different LSSs.Large differences in simulated SAT intensity,threat score,and simulated error under different schemes are identified clearly.In addition,some systematic differences are also in-duced by the LSSs.In terms of threat score from the three LSSs,SLAB is the best,and RUC is better than NOAH.SLAB gives the lowest absolute error for area-averaged SAT,and tends to depict the western Pacific subtropical high with the east-ernmost position at low levels.The LSSs modify the simulated SAT,primarily via the transfer of sensible heat from the land surface to the atmosphere.The physical mechanism of the positive feedback between atmospheric circulation and the SAT is unimportant,with"negative"feedback over most of the simulated areas.This study emphasizes the importance of improving LSSs in SAT forecasting by numerical models.展开更多
文摘利用中尺度数值预报(Weather Research and Forecast,WRF)模式,针对2018年3月17日05—17时(北京时)北京地区的一次降雪过程模拟分析了城市化对降雪的主要影响机制。结果表明,城市化使得北京五环以内降雪量减少,降雨量增加,这主要是由于城市化低层增温效应加强了雪的融化过程,产生混合型降水,距离市中心越近越容易发生混合型降水。城市化对降雪的总降水量和降水的时、空分布也存在一定的影响。降水初期,城市化造成的“城市干热岛”效应不利于水汽的水平和垂直输送,不利于云的形成,地面总降水量减小。随着降水过程的发展,部分冰相粒子融化,使近地面水汽增多,“城市热岛效应”的热力抬升作用有利于水汽的垂直输送和云的发展,部分云滴或水汽抬升进入云中,增强冷云过程,使雪和霰粒子含量增大,地面总降水量增加。城市化产生的“城市效应”对低层大气温度和云微物理过程产生影响,而云微物理过程的非绝热过程反过来又影响低层大气温度和大气层结,影响能量和水汽输送,进而对云和地面降水产生影响。
基金supported by the Knowledge Innovation Program of the Chinese Academy of Sciences (Grant No. KZCX2-YW-Q11-04)the National High Technology Research and Development Program of China (863 Program, Grant No. 2010AA012304)+2 种基金the National Natural Science Foundation of China (Grant No. 40905049)the LASG State Key Laboratory special fundthe LASG free exploration fund
文摘In this study, a 47-day regional climate simulation of the heavy rainfall in the Yangtze-Huai River Basin during the summer of 2003 was conducted using the Weather Research and Forecast （WRY） model. The simulation reproduces reasonably well the evolution of the rainfall during the study period＇s three successive rainy phases, especially the frequent heavy rainfall events occurring in the Huai River Basin. The model captures the major rainfall peak observed by the monitoring stations in the morning. Another peak appears later than that shown by the observations. In addition, the simulation realistically captures not only the evolution of the low-level winds but also the characteristics of their diurnal variation. The strong southwesterly （low-level jet, LLJ） wind speed increases beginning in the early evening and reaches a peak in the morning; it then gradually decreases until the afternoon. The intense LLJ forms a strong convergent circulation pattern in the early morning along the Yangtze-Huai River Basin. This pattern partly explains the rainfall peak observed at this time. This study furnishes a basis for the further analysis of the mechanisms of evolution of the LLJ and for the further study of the interactions between the LLJ and rainfall.
基金Supported by Shandong Meteorological Bureau Key Project (2010sdqxj105)~~
文摘[Objective] The aim was to analyze characters of solar energy in photo- voltaic power stations in Shandong Province. [Method] The models of total solar radiation and scattered radiation were determined, and solar energy resources in pho-tovoltaic power stations were evaluated based on illumination in horizontal plane and cloud data in 123 counties or cities and observed information in Jinan, Fushan and Juxian in 1988-2008. [Result] Solar energy in northern regions in Shandong proved most abundant, which is suitable for photovoltaic power generation; the optimal angle of tilt of photovoltaic array was at 35°, decreasing by 2°-3° compared with local latitude. Total solar radiation received by the slope with optimal angle of tilt exceeded 1 600 kw.h/（m2.a）, increasing by 16% compared with horizontal planes. The maximal irradiance concluded by WRF in different regions tended to be volatile in 1 020-1 060 W/m2. [Conclusion] The research provides references for construction of photovoltaic power stations in Shandong Province.
文摘为了更好地预报重庆地区暴雨发生的时间和落区,利用重庆地区基于GPS得到的GPS-PWV(Precipitable Water Vapor)资料结合WRF数值模拟对2012年一次暴雨过程进行综合分析,分析此次过程中重庆地区GPS-PWV的变化特征、不稳定能量以及动力抬升条件与降水的关系。研究结果表明:此次过程在降水之前有18小时到35小时的水汽聚集过程,在接近水汽通道的迎风坡面降水量转化率较高。综合分析不稳定能量和水汽通量散度的变化结合GPS-PWV提供的水汽场能够更好地预报降水发生的时间和落区。
文摘土地利用和土地覆盖变化(Land Use and Land Cover Chang,LUCC)通过影响局地陆面过程及陆气相互作用进而影响局地天气和气候。为探究LUCC产品对陆气相互作用的影响,本文采用了三套LUCC产品,包括USGS、Landsat和MODIS,模拟研究不同LUCC产品对华东地区土壤和近地面温度、湿度的影响。结果表明,不同LUCC产品的土地利用类型差异主要在城市、农田和以草地、森林为主的自然植被。与USGS产品相比,Landsat和MODIS产品的城市和森林面积分别增加了2%和15%以上,农田面积则减少了17%左右。模拟结果表明,Landsat和MODIS产品的城市面积增加导致该区域的土壤温度和湿度增加,感热通量分别增加了28.1 W·m^(-2)、68.3 W·m^(-2),潜热通量分别减少了28.3 W·m^(-2)、81 W·m^(-2),这使得2 m气温增加了1.5℃左右,相对湿度减小了约9%。USGS产品中的农田和草地在Landsat和MODIS中改变为森林也使得土壤温度、湿度和近地面能量通量、温度和湿度的空间分布随之产生变化,但相比于城市面积改变导致的变化较为复杂。此外,不同LUCC产品之间的城市面积变化对土壤温度、湿度和近地面能量通量、温度和湿度的影响要大于农田和自然植被变化产生的影响。最后,对比三个试验模拟的土壤温度、土壤湿度、2 m气温和相对湿度结果与GLDAS(the Global Land Data Assimilation System)或站点观测资料的相关性、均方根误差、平均偏差和认同指数可以发现,使用更准确、细致的Landsat产品的模式对近地面气象条件的模拟性能要优于USGS和MODIS产品模拟结果。
基金supported by National Natural Science Foundation of China(Grant No.40875067)part by Knowledge Innovation Program of the Chinese Academy of Sciences(Grant No.IAP09306)
文摘The simulations of a heat wave occurring in southern Yangtze-Huaihe valley and southern China during late July,2003 were conducted to examine the sensitivity of simulated surface air temperature(SAT) to different land surface schemes(LSSs) using the Weather Research and Forecasting Model(WRF) Version 2.2 in the short-range mode for 24-h integrations.Initial and boundary conditions employed a National Centers for Environmental Prediction(NCEP) analysis.The results showed that,overall,simulated high-temperature weather is sensitive to different LSSs.Large differences in simulated SAT intensity,threat score,and simulated error under different schemes are identified clearly.In addition,some systematic differences are also in-duced by the LSSs.In terms of threat score from the three LSSs,SLAB is the best,and RUC is better than NOAH.SLAB gives the lowest absolute error for area-averaged SAT,and tends to depict the western Pacific subtropical high with the east-ernmost position at low levels.The LSSs modify the simulated SAT,primarily via the transfer of sensible heat from the land surface to the atmosphere.The physical mechanism of the positive feedback between atmospheric circulation and the SAT is unimportant,with"negative"feedback over most of the simulated areas.This study emphasizes the importance of improving LSSs in SAT forecasting by numerical models.
