ISSN 1000-0526
CN 11-2282/P
CN 11-2282/P
Volume 37,Issue 11,2011 Table of Contents
2011, 37(11):1329-1335.
DOI: 10.7519/j.issn.1000-0526.2011.11.001
Abstract:
By analyzing the daily precipitation data of four provinces along the Huaihe River Valley, and the reanalysis of NCEP 500 hPa height field, the persistent and strong precipitation process (PSPP) along the Huaihe River Valley between 1961 and 2006 was defined. The development and change of the blocking high at high latitudes prior to and during the PSPP were analyzed as well. The research results have brought the conclusion that on average, from June 29 to July 25, the Huaihe River Valley had the highest precipitation. The PSPP happened mostly between midJune to midJuly. Before the PSPP starting, obvious blocking high pattern was found near the Urals, in which double blockings dominated. Whereas during the PSPP, the blocking high near the Urals weakened and that at the north and east of the Lake Baikal became strong, in which a single blocking dominated. The PSPP mostly happened 2 to 5 days after the sharp decrease of the blocking high index. During the years of PSPP, the blocking high near the Urals had an oscillation cycle of 15 to 30 days. In most of the years, the blocking high near the Urals and 180°E moved to the west before the PSPP started. The results in this article are helpful in mastering the characteristics of the strong precipitation along the Huaihe River Valley and precursor signal, and lay the basis for the forecasting of the persistent and strong precipitation along the Huaihe River Valley.
By analyzing the daily precipitation data of four provinces along the Huaihe River Valley, and the reanalysis of NCEP 500 hPa height field, the persistent and strong precipitation process (PSPP) along the Huaihe River Valley between 1961 and 2006 was defined. The development and change of the blocking high at high latitudes prior to and during the PSPP were analyzed as well. The research results have brought the conclusion that on average, from June 29 to July 25, the Huaihe River Valley had the highest precipitation. The PSPP happened mostly between midJune to midJuly. Before the PSPP starting, obvious blocking high pattern was found near the Urals, in which double blockings dominated. Whereas during the PSPP, the blocking high near the Urals weakened and that at the north and east of the Lake Baikal became strong, in which a single blocking dominated. The PSPP mostly happened 2 to 5 days after the sharp decrease of the blocking high index. During the years of PSPP, the blocking high near the Urals had an oscillation cycle of 15 to 30 days. In most of the years, the blocking high near the Urals and 180°E moved to the west before the PSPP started. The results in this article are helpful in mastering the characteristics of the strong precipitation along the Huaihe River Valley and precursor signal, and lay the basis for the forecasting of the persistent and strong precipitation along the Huaihe River Valley.
2011, 37(11):1336-1342.
DOI: 10.7519/j.issn.1000-0526.2011.11.002
Abstract:
In this study, we assess the ability of the Model AGCM BCC_AGCM2.0.1 to reproduce the precipitation days with different rainfall amount under the atmospheric circulation. By the Cumulative Frequency Distribution (CFD) method, the rainy period in observations is from the fifth pentad of June to the second pentad of July, while the simulated rainy period is from the first pentad to the third pentad of June. Thus the simulation period preceded the observation period by 20 days. Over the YangtzeHuaihe River Basin in general, stormy and heavy rainy days are more, but the moderate and light rainy days are less. Over recent 40 years, as observations indicated, the light rainy days decrease, while the other three rainy days increase. The trend in simulation is opposite to the observation.
In this study, we assess the ability of the Model AGCM BCC_AGCM2.0.1 to reproduce the precipitation days with different rainfall amount under the atmospheric circulation. By the Cumulative Frequency Distribution (CFD) method, the rainy period in observations is from the fifth pentad of June to the second pentad of July, while the simulated rainy period is from the first pentad to the third pentad of June. Thus the simulation period preceded the observation period by 20 days. Over the YangtzeHuaihe River Basin in general, stormy and heavy rainy days are more, but the moderate and light rainy days are less. Over recent 40 years, as observations indicated, the light rainy days decrease, while the other three rainy days increase. The trend in simulation is opposite to the observation.
2011, 37(11):1343-1351.
DOI: 10.7519/j.issn.1000-0526.2011.11.003
Abstract:
Usually, the time of the first snowfall in Beijing is about on November 28. During the period of the nighttime of October 31, 2009 to daytime of November 1, 2009, there was a weather process which never occurs over the past 22 years. In this process, the precipitation firstly acted as rain, then converted to sleet and finally in the form of snow. Analysis shows that, over the north region of the Yellow River in middle and east parts of North China, the lower troposphere was controlled by northwest flows for 6 hours even to 12 hours before this snowfall, thus the transport and accumulation of water vapor were not obvious. This snowfall process is infrequent for Beijing in such a dry condition in October. The dynamic calculation and analysis of this snowfall process were conducted with the MICAPS data of CMA, windprofiler, radiometric and surface automatic weather station observations in Beijing. The result shows that, the dynamic action of the southward outbreak of strong cold air from Baikal Lake in upper troposphere was the main reason for this snowfall process. A 500 hPa positive vorticity advection area, a middle and upper tropospheric divergence center and a middle and lower tropospheric convergence center were vertically distributed over Beijing, which support the favorable environment for vertical motion; the coactions of the warm and humid sourheast winds near the ground in piedmonts and plains, the cold and humid east winds in the boundary layer, the west winds in tropospheric bottom, which were seen in windprofiler, and the topographic effect in western Beijing will generate an uplift and local convection to enhance snowfall in southwest Beijing. This paper proposes a conceptual model about how the wind distribution in windprofiler in the piedmonts and plains of Beijing and the topographic effect will generate the uplift motion and local convection. The water vapor condition of this snowfall is from the shortterm growth of humidity by nearsurface southerly winds and southeast winds, and the local moisture convergence in the lower troposphere.
Usually, the time of the first snowfall in Beijing is about on November 28. During the period of the nighttime of October 31, 2009 to daytime of November 1, 2009, there was a weather process which never occurs over the past 22 years. In this process, the precipitation firstly acted as rain, then converted to sleet and finally in the form of snow. Analysis shows that, over the north region of the Yellow River in middle and east parts of North China, the lower troposphere was controlled by northwest flows for 6 hours even to 12 hours before this snowfall, thus the transport and accumulation of water vapor were not obvious. This snowfall process is infrequent for Beijing in such a dry condition in October. The dynamic calculation and analysis of this snowfall process were conducted with the MICAPS data of CMA, windprofiler, radiometric and surface automatic weather station observations in Beijing. The result shows that, the dynamic action of the southward outbreak of strong cold air from Baikal Lake in upper troposphere was the main reason for this snowfall process. A 500 hPa positive vorticity advection area, a middle and upper tropospheric divergence center and a middle and lower tropospheric convergence center were vertically distributed over Beijing, which support the favorable environment for vertical motion; the coactions of the warm and humid sourheast winds near the ground in piedmonts and plains, the cold and humid east winds in the boundary layer, the west winds in tropospheric bottom, which were seen in windprofiler, and the topographic effect in western Beijing will generate an uplift and local convection to enhance snowfall in southwest Beijing. This paper proposes a conceptual model about how the wind distribution in windprofiler in the piedmonts and plains of Beijing and the topographic effect will generate the uplift motion and local convection. The water vapor condition of this snowfall is from the shortterm growth of humidity by nearsurface southerly winds and southeast winds, and the local moisture convergence in the lower troposphere.
2011, 37(11):1352-1359.
DOI: 10.7519/j.issn.1000-0526.2011.11.004
Abstract:
Based on the observed data and output data from MM5, the causes for the blizzard process in Hebei Province form November 10 to 11 in 2009 are analyzed. The results show that a cold front system influences Hebei Province for a long time and brings about positive and contrary bidirectional secondary circulations with strong upward flows and convergence at the middle levels coupled with positive vorticity column, which are the main dynamic factors for snowstorm. On the other hand the results show that the conditional symmetric instability and convective instability are formed in the blizzard area due to the stronger temperature gradient and wind vertical shear. Moreover, plentiful water vapor is transported to Hebei through the southwest warm and wet airflows, which change into snow and ice by deposition and freezing when being carried to the higher cold levels. The northeast dry and cold airflows acting as a cold wedge of backflow snowfall are accumulated and lifted in the lower level because of the eastward bellmouthed topography. It favors development of severe convective weather when the two kinds of upward flows caused by topography and frontsurface secondary circulation are superimposed.
Based on the observed data and output data from MM5, the causes for the blizzard process in Hebei Province form November 10 to 11 in 2009 are analyzed. The results show that a cold front system influences Hebei Province for a long time and brings about positive and contrary bidirectional secondary circulations with strong upward flows and convergence at the middle levels coupled with positive vorticity column, which are the main dynamic factors for snowstorm. On the other hand the results show that the conditional symmetric instability and convective instability are formed in the blizzard area due to the stronger temperature gradient and wind vertical shear. Moreover, plentiful water vapor is transported to Hebei through the southwest warm and wet airflows, which change into snow and ice by deposition and freezing when being carried to the higher cold levels. The northeast dry and cold airflows acting as a cold wedge of backflow snowfall are accumulated and lifted in the lower level because of the eastward bellmouthed topography. It favors development of severe convective weather when the two kinds of upward flows caused by topography and frontsurface secondary circulation are superimposed.
2011, 37(11):1360-1364.
DOI: 10.7519/j.issn.1000-0526.2011.11.005
Abstract:
Ensemble empirical mode decomposition (EEMD) method was adopted to study the nonstationary interannual variations of the high temperature days in Nanjing summer. Using the EEMD method, the days of the high temperature in Nanjing during 55 years (1946-2000) can be decomposed into a series of modes, including a quasibiennial oscillation (QBO) component and a 6year component. Among those, the QBO with the larger amplitude has the high correlations with original numbers of the high temperature. In brief, the EEMD method other than the traditional and conventional methods can bring us the isolated characteristics of variations of high temperature days at various time scales for the interannual timescale. Moreover, the above two modes correspond to the different wave trains of the global meridional wind at 200 hPa. The former is over South Asia, the South China Sea, the subtropical western Pacific and the Sea of Japan, the middle latitude of North America, and the high and middle latitudes of the southern Indian and southern Atlantic Ocean, while the latter is over the high and middle latitudes of Eurasia. These relationships are of indicative guidance for the climatic prediction of the high temperature days in Nanjing.
Ensemble empirical mode decomposition (EEMD) method was adopted to study the nonstationary interannual variations of the high temperature days in Nanjing summer. Using the EEMD method, the days of the high temperature in Nanjing during 55 years (1946-2000) can be decomposed into a series of modes, including a quasibiennial oscillation (QBO) component and a 6year component. Among those, the QBO with the larger amplitude has the high correlations with original numbers of the high temperature. In brief, the EEMD method other than the traditional and conventional methods can bring us the isolated characteristics of variations of high temperature days at various time scales for the interannual timescale. Moreover, the above two modes correspond to the different wave trains of the global meridional wind at 200 hPa. The former is over South Asia, the South China Sea, the subtropical western Pacific and the Sea of Japan, the middle latitude of North America, and the high and middle latitudes of the southern Indian and southern Atlantic Ocean, while the latter is over the high and middle latitudes of Eurasia. These relationships are of indicative guidance for the climatic prediction of the high temperature days in Nanjing.
2011, 37(11):1365-1371.
DOI: 10.7519/j.issn.1000-0526.2011.11.006
Abstract:
At 02:00 BT 28 February 2007, a train of No.5807 from Urumqi to Aksu encountered terrible gale winds, which were caused by northerly cold wave, at the socalled 30 km wind gap in Xinjiang, leading to that the 11 carriages were derailed and overturned. By using mesoscale model WRF, a numerical simulation was made for the gale process. The results show that the WRF can simulate the variation and distribution of the gale in the 30 km wind gap, but the wind velocity of simulation is lower than that of observation, and variation trends of wind velocity are nearly to observations. It may be concluded that the high pressure gradient and special landform are the main reasons of the gale. Meanwhile, both funnel effect and downslope wind also exist.
At 02:00 BT 28 February 2007, a train of No.5807 from Urumqi to Aksu encountered terrible gale winds, which were caused by northerly cold wave, at the socalled 30 km wind gap in Xinjiang, leading to that the 11 carriages were derailed and overturned. By using mesoscale model WRF, a numerical simulation was made for the gale process. The results show that the WRF can simulate the variation and distribution of the gale in the 30 km wind gap, but the wind velocity of simulation is lower than that of observation, and variation trends of wind velocity are nearly to observations. It may be concluded that the high pressure gradient and special landform are the main reasons of the gale. Meanwhile, both funnel effect and downslope wind also exist.
2011, 37(11):1372-1379.
DOI: 10.7519/j.issn.1000-0526.2011.11.007
Abstract:
Based on the data from automatic weather stations in the Qiongzhou Strait northern and southern coasts, the distribution patterns of high wind events in both coastal zones were analyzed. And the difference between them was also analyzed using weather systems. The high wind events are defined into two kinds: sustained winds and gust winds. The results are as follows: In southern coast, the high wind events are more frequent than in northern coast, but the speeds of gust winds are obviously bigger in northern coast than in southern coast. The high wind events in northern coastal zones and the sustained wind events in southern coastal zones mainly happen in autumn and winter but rare in other seasons, and the sustained wind events in both coastal zones mainly occurred by cold air. But the gust wind events in the southern coastal are quite special, which mainly happen in autumn and rarely occurred by cold air. In both coastal zones of the Qiongzhou Strait, the high wind events happen with more frequency and bigger speed on the east entrance than on the west entrance, and with the least in the middle of coastal zones. There exist pronounced phenomena that the northeast high wind was donsinant in both coasts of the strait. The high wind events are more easily occurred by cold air from east than from west. The Qiongzhou Strait can obviously make the turbulent intensity of cold air turning weak.
Based on the data from automatic weather stations in the Qiongzhou Strait northern and southern coasts, the distribution patterns of high wind events in both coastal zones were analyzed. And the difference between them was also analyzed using weather systems. The high wind events are defined into two kinds: sustained winds and gust winds. The results are as follows: In southern coast, the high wind events are more frequent than in northern coast, but the speeds of gust winds are obviously bigger in northern coast than in southern coast. The high wind events in northern coastal zones and the sustained wind events in southern coastal zones mainly happen in autumn and winter but rare in other seasons, and the sustained wind events in both coastal zones mainly occurred by cold air. But the gust wind events in the southern coastal are quite special, which mainly happen in autumn and rarely occurred by cold air. In both coastal zones of the Qiongzhou Strait, the high wind events happen with more frequency and bigger speed on the east entrance than on the west entrance, and with the least in the middle of coastal zones. There exist pronounced phenomena that the northeast high wind was donsinant in both coasts of the strait. The high wind events are more easily occurred by cold air from east than from west. The Qiongzhou Strait can obviously make the turbulent intensity of cold air turning weak.
2011, 37(11):1380-1388.
DOI: 10.7519/j.issn.1000-0526.2011.11.008
Abstract:
The typical returnflow events with heavy snow during 2-3 January, 2010 by using Beijing local highresolution rapid update cycle mesoscale model system (BJRUC) are simulated. The characteristics of synoptic system in each layer and key snowfall factor are analyzed. The results show that the BJRUC model can well simulate the snowfall distribution, position and time change, and the main situations of heavy snowfall which are caused by the cold air returnflow in the lowlevel， and the 850-700 hPa layer lowvortex system. But the snowfall center has still some deficiency. When the vertical ascending motion is produced in lower atmosphere by the cold returnflow encountering terrain, the snowfall is not high. During the snowfall, the dynamic lifting which is caused by the cold returnflow combining with the ascending motion of the foreside of low vortex, forms a deeply and violent ascending motion, that is the key factor to cause the heavy snow. The durative and cold returnflow with high humidity transports water vapor in the lower atmosphere. The humidity in the lowermid troposphere is increased by the southwestern air flow. The returnflow increases thickness of wetlayer, reaching above 600 hPa. It plays an important role in producing the heavy snow. The start and intensity of snow fall are related to the moment of the direction change to southern wind and the south wind speed.
The typical returnflow events with heavy snow during 2-3 January, 2010 by using Beijing local highresolution rapid update cycle mesoscale model system (BJRUC) are simulated. The characteristics of synoptic system in each layer and key snowfall factor are analyzed. The results show that the BJRUC model can well simulate the snowfall distribution, position and time change, and the main situations of heavy snowfall which are caused by the cold air returnflow in the lowlevel， and the 850-700 hPa layer lowvortex system. But the snowfall center has still some deficiency. When the vertical ascending motion is produced in lower atmosphere by the cold returnflow encountering terrain, the snowfall is not high. During the snowfall, the dynamic lifting which is caused by the cold returnflow combining with the ascending motion of the foreside of low vortex, forms a deeply and violent ascending motion, that is the key factor to cause the heavy snow. The durative and cold returnflow with high humidity transports water vapor in the lower atmosphere. The humidity in the lowermid troposphere is increased by the southwestern air flow. The returnflow increases thickness of wetlayer, reaching above 600 hPa. It plays an important role in producing the heavy snow. The start and intensity of snow fall are related to the moment of the direction change to southern wind and the south wind speed.
2011, 37(11):1389-1394.
DOI: 10.7519/j.issn.1000-0526.2011.11.009
Abstract:
Using the airborne observation data from two continuous flights on 26 and 27 October 2008, this paper analyzes the cloud microphysical characteristics and precipitation mechanisms of the observed cloud system to reveal the microphysical process of precipitation in Sichuan Basin. The results show that: (1) The observed cloud system is a deep mixed cloud system, with cold in the upper layer and warm in the lower layer. The cloud top is around -10℃, and the 0℃ layer is high. The warm layer is deep (around 3200 m), while the cold layer is correspondingly thin (around 1800 m). (2) From top to bottom in the supercooled layer, the size spectra of the large cloud particles and precipitation particles become remarkably wider. (3) In the warm layer, the precipitation particles become smaller and decreased. (4) The existence of ice nuclei and supercooled water initiates the cold cloud process. The latter coordinates with the warm cloud process in the warm layer, and then the ground precipitation achieves. However, supercooled water is not abundant, and the precipitation particles formed are not plentiful, as well as the liquid water content in the warm layer is small, thus, the ground precipitation is small.
Using the airborne observation data from two continuous flights on 26 and 27 October 2008, this paper analyzes the cloud microphysical characteristics and precipitation mechanisms of the observed cloud system to reveal the microphysical process of precipitation in Sichuan Basin. The results show that: (1) The observed cloud system is a deep mixed cloud system, with cold in the upper layer and warm in the lower layer. The cloud top is around -10℃, and the 0℃ layer is high. The warm layer is deep (around 3200 m), while the cold layer is correspondingly thin (around 1800 m). (2) From top to bottom in the supercooled layer, the size spectra of the large cloud particles and precipitation particles become remarkably wider. (3) In the warm layer, the precipitation particles become smaller and decreased. (4) The existence of ice nuclei and supercooled water initiates the cold cloud process. The latter coordinates with the warm cloud process in the warm layer, and then the ground precipitation achieves. However, supercooled water is not abundant, and the precipitation particles formed are not plentiful, as well as the liquid water content in the warm layer is small, thus, the ground precipitation is small.
2011, 37(11):1395-1401.
DOI: 10.7519/j.issn.1000-0526.2011.11.010
Abstract:
Comparing with infrared and visible radiation, microwave radiation has the advantage to penetrate into thin cloud. Satellite microwave sounding data make great contributions to numerical weather prediction (NWP). The main usage of satellite microwave sounding data in NWP is to assimilate into the initial field. However, the observation operator used in assimilation of satellite microwave sounding data has large simulation errors under the conditions of cloud, precipitation and complicated land surface. Besides, the error of some microwave sounding data is also very large. Therefore how to choose microwave sounding data is a crucial issue in data assimilation. To guarantee the result of assimilation and use more sounding data, in the research of AMSU sounding data assimilation, many institutions and scholars have invented quality control schemes such as scatter index and rain detection to remove data that not well simulated by observation operator. Research shows that after using quality control in data assimilation, the assimilated output is improved and the accuracy of NWP is increased. But there is no detailed analysis on the theory and using condition of quality control so far, which makes the quality control used in research institutions quite different. In this paper, the source of the assimilation error and the principle of quality control are analyzed firstly. Then the quality control schemes used at the main operational NWP center are summarized. Finally, the future development of quality control is discussed briefly.
Comparing with infrared and visible radiation, microwave radiation has the advantage to penetrate into thin cloud. Satellite microwave sounding data make great contributions to numerical weather prediction (NWP). The main usage of satellite microwave sounding data in NWP is to assimilate into the initial field. However, the observation operator used in assimilation of satellite microwave sounding data has large simulation errors under the conditions of cloud, precipitation and complicated land surface. Besides, the error of some microwave sounding data is also very large. Therefore how to choose microwave sounding data is a crucial issue in data assimilation. To guarantee the result of assimilation and use more sounding data, in the research of AMSU sounding data assimilation, many institutions and scholars have invented quality control schemes such as scatter index and rain detection to remove data that not well simulated by observation operator. Research shows that after using quality control in data assimilation, the assimilated output is improved and the accuracy of NWP is increased. But there is no detailed analysis on the theory and using condition of quality control so far, which makes the quality control used in research institutions quite different. In this paper, the source of the assimilation error and the principle of quality control are analyzed firstly. Then the quality control schemes used at the main operational NWP center are summarized. Finally, the future development of quality control is discussed briefly.
2011, 37(11):1402-1408.
DOI: 10.7519/j.issn.1000-0526.2011.11.011
Abstract:
By using not only the daily precipitation and temperature data at 77 stations of Anhui Province during 1961-2009, but also the soil moisture data in all stations from the start of the record to 2009, this paper analyzes the application of the improved CI index in Anhui Province. The results show that in the aspects of statistic characteristics, its correlation to soil moisture, the spatial distribution of drought and so on, the improved CI (NCC2CI) index inherits the advantages of the OldCI index, but in the aspect of diagnosis of the daily evolution of the drought process, the NCC2CI index has much improvements compared with the OldCI index. As to the drought monitoring in Anhui Province, the NCC2CI index is superior over the OldCI index obviously.
By using not only the daily precipitation and temperature data at 77 stations of Anhui Province during 1961-2009, but also the soil moisture data in all stations from the start of the record to 2009, this paper analyzes the application of the improved CI index in Anhui Province. The results show that in the aspects of statistic characteristics, its correlation to soil moisture, the spatial distribution of drought and so on, the improved CI (NCC2CI) index inherits the advantages of the OldCI index, but in the aspect of diagnosis of the daily evolution of the drought process, the NCC2CI index has much improvements compared with the OldCI index. As to the drought monitoring in Anhui Province, the NCC2CI index is superior over the OldCI index obviously.
2011, 37(11):1409-1414.
DOI: 10.7519/j.issn.1000-0526.2011.11.012
Abstract:
It is very significant to provide highlevel weather service for largescale events such as the 60th anniversary of National Day of the People’s Republic of China. In order to continuously improve the quality of largescale event weather service, it is necessary to assess the customer satisfaction degree of weather service from the users’ point of view. In this paper, the decisionmaking weather service for the 60th anniversary of National Day of the People’s Republic of China, was generally assessed using a weather service customer satisfaction degree index (WSCSI). The perception of users’ needs, weather service quality, ways of weather service, the ability of onsite service, weather early warning, emergency weather service and the overall benefits of weather services were analyzed deeply. Analysis results have shown that the average WSCSI reaches 97%, and the WSCSI for high impact weather reaches only 93%, thus the gap between satisfaction and expectation for it is relatively wider (6.7%). Further analyses have indicated that weather services satisfied customers’ needs in high level， and the ability of forecast and service for high impact weather still needs to be improved. Through the impact assessment on weather service, meteorological department could thoroughly learn the service social and economic effects and find where need to improve, and thus strive to take measures to fill the gap between customers’ satisfaction and expectation. It is helpful for meteorological department to gather experiences for the decisionmaking weather service of largescale event.
It is very significant to provide highlevel weather service for largescale events such as the 60th anniversary of National Day of the People’s Republic of China. In order to continuously improve the quality of largescale event weather service, it is necessary to assess the customer satisfaction degree of weather service from the users’ point of view. In this paper, the decisionmaking weather service for the 60th anniversary of National Day of the People’s Republic of China, was generally assessed using a weather service customer satisfaction degree index (WSCSI). The perception of users’ needs, weather service quality, ways of weather service, the ability of onsite service, weather early warning, emergency weather service and the overall benefits of weather services were analyzed deeply. Analysis results have shown that the average WSCSI reaches 97%, and the WSCSI for high impact weather reaches only 93%, thus the gap between satisfaction and expectation for it is relatively wider (6.7%). Further analyses have indicated that weather services satisfied customers’ needs in high level， and the ability of forecast and service for high impact weather still needs to be improved. Through the impact assessment on weather service, meteorological department could thoroughly learn the service social and economic effects and find where need to improve, and thus strive to take measures to fill the gap between customers’ satisfaction and expectation. It is helpful for meteorological department to gather experiences for the decisionmaking weather service of largescale event.
2011, 37(11):1415-1422.
DOI: 10.7519/j.issn.1000-0526.2011.11.013
Abstract:
Based on the typhoon precipitation data from seven stations in Hangzhou City during the period from 1960 to 2009 and combined with the society economic and natural geographic factors, this study builds a set of typhoon rainstorm flooding disaster assessment model including hazard factors, hazard inducing environment, hazardaffected body and disaster prevention ability. And a map of Hangzhou’s typhoon rainstorm flooding disaster risk division was drawn using 100 m × 100 m raster as basic assessment unit, by means of GIS spatial analysis technique for rasterizing evaluation indices and fuzzy comprehensive assessment methods. Finally, the five risk zones of Hangzhou, i.e. higher risk, subhigh risk, medium risk, inferior risk and lower risk, were mapped. Results show that the typhoon rainstorm flooding disaster risk in Hangzhou has an increasing tendency from southwest to northeast. The coastal plain, involved with Xiaoshan District, Yuhang City, main urban area of Hangzhou, and so on, has relative high risk, while the midwest mountain and hilly area, involved with Jiande City, Chun’an County, and so on, has slightly lower risk.
Based on the typhoon precipitation data from seven stations in Hangzhou City during the period from 1960 to 2009 and combined with the society economic and natural geographic factors, this study builds a set of typhoon rainstorm flooding disaster assessment model including hazard factors, hazard inducing environment, hazardaffected body and disaster prevention ability. And a map of Hangzhou’s typhoon rainstorm flooding disaster risk division was drawn using 100 m × 100 m raster as basic assessment unit, by means of GIS spatial analysis technique for rasterizing evaluation indices and fuzzy comprehensive assessment methods. Finally, the five risk zones of Hangzhou, i.e. higher risk, subhigh risk, medium risk, inferior risk and lower risk, were mapped. Results show that the typhoon rainstorm flooding disaster risk in Hangzhou has an increasing tendency from southwest to northeast. The coastal plain, involved with Xiaoshan District, Yuhang City, main urban area of Hangzhou, and so on, has relative high risk, while the midwest mountain and hilly area, involved with Jiande City, Chun’an County, and so on, has slightly lower risk.
2011, 37(11):1423-1430.
DOI: 10.7519/j.issn.1000-0526.2011.11.014
Abstract:
Based on the data from Hefei and its surrounding sites and MSS, TM and ETM data of Hefei City, and GIS technology, the land use/cover change (LUCC) situations of buffer areas， which are apart 1, 2.5, 4 km from Hefei observation field and 20 km from Hefei urban areas， were extracted. Variations of annual average, maximum and minimum temperatures (Tave , Tmax and Tmin) were analyzed in Hefei and its surrounding sites, respectively. Furthermore, the regression model between LUCC of Hefei observation field and temperature was established, and a sensitivity analysis was also made. The results have shown that in recent 40 years, the urban area of Hefei has been expanding, thus leading to the site entering into city. Due to this, Hefei Site moved to the suburbs in 1979 and 2004, respectively. After that the temperature difference between Hefei and its surrounding sites became smaller. Because of Hefei Site entering into city, increasing rates of three temperatures in Hefei Site were significantly higher than those in its surrounding sites, and the differences of Tave ,Tmax and Tmin between Hefei and its surrounding sites became bigger. The regression model between LUCC and the temperature in different buffers area showed that impacts of LUCC on Tave ,Tmax and Tmin were not sensitive in Hefei observation field’s 1 and 2.5 km buffer areas. Similarly, impacts of LUCC on Tmax were not sensitive in Hefei observation field’s 4 km buffer area, while impacts of LUCC on Tave and Tmin were significant. Specifically, the increased building areas had a positive contribution to Tave and Tmin in Hefei observation field’s 4 km buffer area; Oppositely, the increased farmland, vegetation, water body areas had a negative effect on Tave and Tmin
Based on the data from Hefei and its surrounding sites and MSS, TM and ETM data of Hefei City, and GIS technology, the land use/cover change (LUCC) situations of buffer areas， which are apart 1, 2.5, 4 km from Hefei observation field and 20 km from Hefei urban areas， were extracted. Variations of annual average, maximum and minimum temperatures (Tave , Tmax and Tmin) were analyzed in Hefei and its surrounding sites, respectively. Furthermore, the regression model between LUCC of Hefei observation field and temperature was established, and a sensitivity analysis was also made. The results have shown that in recent 40 years, the urban area of Hefei has been expanding, thus leading to the site entering into city. Due to this, Hefei Site moved to the suburbs in 1979 and 2004, respectively. After that the temperature difference between Hefei and its surrounding sites became smaller. Because of Hefei Site entering into city, increasing rates of three temperatures in Hefei Site were significantly higher than those in its surrounding sites, and the differences of Tave ,Tmax and Tmin between Hefei and its surrounding sites became bigger. The regression model between LUCC and the temperature in different buffers area showed that impacts of LUCC on Tave ,Tmax and Tmin were not sensitive in Hefei observation field’s 1 and 2.5 km buffer areas. Similarly, impacts of LUCC on Tmax were not sensitive in Hefei observation field’s 4 km buffer area, while impacts of LUCC on Tave and Tmin were significant. Specifically, the increased building areas had a positive contribution to Tave and Tmin in Hefei observation field’s 4 km buffer area; Oppositely, the increased farmland, vegetation, water body areas had a negative effect on Tave and Tmin
2011, 37(11):1431-1437.
DOI: 10.7519/j.issn.1000-0526.2011.11.015
Abstract:
In order to do well the public meteorological service and improve the situation that product forms of meteorological service are single, the authors mainly explore the key technologies that FY2 satellite data of the MICAPS software are browsed and analyzed in the web environment. Selecting ArcGIS Engine as the secondary development components, the authors realized the data format conversion from FY2 satellite image to multiple band ArcGIS’s img format raster data, which have the custom color and projection. Then choosing ArcGIS Server as the web development components, the authors constructed the web publishing platform of the satellite raster data, which can publish, query and browse the satellite data. The authors also proposed and realized the simple quantitative analysis and statistics of the data in the network environment by the GIS analysis method. Test results show that this platform can be run on the current Web environment efficiently, and it can adapt to the current bandwidth fully and meet the browse and analysis requirements of the mainstream computer. This platform supplies the meteorological information to aid in decision making for the public to know the weather in advance and the weatherman to make weather forecast and weather warning, which makes a great advance in the construction of public meteorological services for the local weather department.
In order to do well the public meteorological service and improve the situation that product forms of meteorological service are single, the authors mainly explore the key technologies that FY2 satellite data of the MICAPS software are browsed and analyzed in the web environment. Selecting ArcGIS Engine as the secondary development components, the authors realized the data format conversion from FY2 satellite image to multiple band ArcGIS’s img format raster data, which have the custom color and projection. Then choosing ArcGIS Server as the web development components, the authors constructed the web publishing platform of the satellite raster data, which can publish, query and browse the satellite data. The authors also proposed and realized the simple quantitative analysis and statistics of the data in the network environment by the GIS analysis method. Test results show that this platform can be run on the current Web environment efficiently, and it can adapt to the current bandwidth fully and meet the browse and analysis requirements of the mainstream computer. This platform supplies the meteorological information to aid in decision making for the public to know the weather in advance and the weatherman to make weather forecast and weather warning, which makes a great advance in the construction of public meteorological services for the local weather department.
2011, 37(11):1438-1442.
DOI: 10.7519/j.issn.1000-0526.2011.11.016
Abstract:
Using Data Envelopment Analysis (DEA in short) method to assess the efficiency of Shaanxi meteorological resources, the synthetic efficiency, technical efficiency, and scale efficiency of Shaanxi meteorological services were calculated from 2007 to 2009 and the general state is as follows. The averages of synthetic efficiency and scale efficiency have somewhat decreases, while technical efficiency increases. Their comparison shows that technical efficiency has top value in 2009 and the lowest in 2007. According to values of both synthetic efficiency and scale efficiency, they have top values in 2008 and the lowest in 2009. Factors affecting efficiency are analyzed by econometric modeling using Panel Data Model. Results show that CSIWSs (Customs and the public Satisfaction Index of Weather Services), and proportion of agricultural yields and investing funds have significant positive relationships with synthetic efficiency, and the number of academic papers constitutes a reverse relation with synthetic efficiency. According to those analyses, some effective countermeasures are put forward.
Using Data Envelopment Analysis (DEA in short) method to assess the efficiency of Shaanxi meteorological resources, the synthetic efficiency, technical efficiency, and scale efficiency of Shaanxi meteorological services were calculated from 2007 to 2009 and the general state is as follows. The averages of synthetic efficiency and scale efficiency have somewhat decreases, while technical efficiency increases. Their comparison shows that technical efficiency has top value in 2009 and the lowest in 2007. According to values of both synthetic efficiency and scale efficiency, they have top values in 2008 and the lowest in 2009. Factors affecting efficiency are analyzed by econometric modeling using Panel Data Model. Results show that CSIWSs (Customs and the public Satisfaction Index of Weather Services), and proportion of agricultural yields and investing funds have significant positive relationships with synthetic efficiency, and the number of academic papers constitutes a reverse relation with synthetic efficiency. According to those analyses, some effective countermeasures are put forward.
2011, 37(11):1443-1447.
DOI: 10.7519/j.issn.1000-0526.2011.11.017
Abstract:
According to the previous various forecasting verification results concerning similarity measurements and starting from formulas, the fact that there exist the same features between similarity parameter and Hamming distance is analyzed and then proved. Meanwhile, the limitations of similarity parameter in similarity forecasting are discussed. The data from 96 different stations at 850 hPa height fields in East Asia during 1-30 May 2010 are utilized to make selection experiments among several frequently used similarity measurements and a new one is proposed by the authors in this paper. The results indicate that, (1) similarity parameter and Hamming distance are very much similar, with over 80% selected samples being the same; (2) similarity parameter has the biggest difference from similarity coefficient, with over 70% selected samples being different; and (3) the new analog quantity is more similar to the correlation coefficient, with 60% being the same. Similarity parameter and Hamming distance reflect how much the distances of the samples are similar to each other, while correlation coefficient and the new analog quantity reflect how much the shapes of the selected samples are similar to each other.
According to the previous various forecasting verification results concerning similarity measurements and starting from formulas, the fact that there exist the same features between similarity parameter and Hamming distance is analyzed and then proved. Meanwhile, the limitations of similarity parameter in similarity forecasting are discussed. The data from 96 different stations at 850 hPa height fields in East Asia during 1-30 May 2010 are utilized to make selection experiments among several frequently used similarity measurements and a new one is proposed by the authors in this paper. The results indicate that, (1) similarity parameter and Hamming distance are very much similar, with over 80% selected samples being the same; (2) similarity parameter has the biggest difference from similarity coefficient, with over 70% selected samples being different; and (3) the new analog quantity is more similar to the correlation coefficient, with 60% being the same. Similarity parameter and Hamming distance reflect how much the distances of the samples are similar to each other, while correlation coefficient and the new analog quantity reflect how much the shapes of the selected samples are similar to each other.
2011, 37(11):1448-1452.
DOI: 10.7519/j.issn.1000-0526.2011.11.018
Abstract:
In order to improve the application ability to T639 model, a synoptic verification about its mediumrange forecasting （120 h leading time） during the summer of 2011 is made in comparison with the counterparts of the models of ECMWF and Japan. The results show that the three models all have good performance on predicting the largescale circulation evolution and adjustment over Asian middle and high latitude areas. As a whole, ECMWF is the best at forecasting synoptic systems and elements among all models. However, the three models have bigger errors on prediction of the track and intensity of typhoon MUIFA except that T639 model performs well after typhoon landing.
In order to improve the application ability to T639 model, a synoptic verification about its mediumrange forecasting （120 h leading time） during the summer of 2011 is made in comparison with the counterparts of the models of ECMWF and Japan. The results show that the three models all have good performance on predicting the largescale circulation evolution and adjustment over Asian middle and high latitude areas. As a whole, ECMWF is the best at forecasting synoptic systems and elements among all models. However, the three models have bigger errors on prediction of the track and intensity of typhoon MUIFA except that T639 model performs well after typhoon landing.
2011, 37(11):1453-1458.
DOI: 10.7519/j.issn.1000-0526.2011.11.019
Abstract:
The software system designed and built for the information management and the operation command to advance the ability of Anhui weather modification has been finished. With the application of the database and the network technology， and based on the information database of weather modification designed and built， the system manages the information using both limits of role and permission. With the reasonable design in the procedures of the operation in Anhui weather modification， and providing some guidance products， and using the technique control over the crucial safety section， the system is providing a good software platform for security， and playing an important role in practical work and the process for command.
The software system designed and built for the information management and the operation command to advance the ability of Anhui weather modification has been finished. With the application of the database and the network technology， and based on the information database of weather modification designed and built， the system manages the information using both limits of role and permission. With the reasonable design in the procedures of the operation in Anhui weather modification， and providing some guidance products， and using the technique control over the crucial safety section， the system is providing a good software platform for security， and playing an important role in practical work and the process for command.
2011, 37(11):1466-1472.
DOI: 10.7519/j.issn.1000-0526.2011.11.020
Abstract:
Based on the 8th WMO international radionsonde system intercomparison, the systematic evaluation for Chinese GTS12 radiosonde system was carried out. The initial evaluation results show that the systematic error and standard deviation for temperature, pressure and geopotential height are 0.2℃ (below 33 km) and 1℃, 0.7 hPa and 1 hPa, and 40 gpm (below 33 km) and 320 gpm, respectively, which have better consistent performance, but the radiation correction algorithm needs further improving. On the other side, the relative humidity measurement gap still exists between China and foreign developed countries, especially focuses should be on the obvious large time constant and small reactive amplitude below -30℃--50℃. Finally, it should be mentioned that wind measurements for secondary wind finding method are very close to GPS wind finding measurements.
Based on the 8th WMO international radionsonde system intercomparison, the systematic evaluation for Chinese GTS12 radiosonde system was carried out. The initial evaluation results show that the systematic error and standard deviation for temperature, pressure and geopotential height are 0.2℃ (below 33 km) and 1℃, 0.7 hPa and 1 hPa, and 40 gpm (below 33 km) and 320 gpm, respectively, which have better consistent performance, but the radiation correction algorithm needs further improving. On the other side, the relative humidity measurement gap still exists between China and foreign developed countries, especially focuses should be on the obvious large time constant and small reactive amplitude below -30℃--50℃. Finally, it should be mentioned that wind measurements for secondary wind finding method are very close to GPS wind finding measurements.
Mobile website
® 2024 All Rights Reserved
Supported by:Beijing E-Tiller Technology Development Co., Ltd.
ISSN:1000-0526 CN:11-2282/P