ISSN 1000-0526
CN 11-2282/P
CN 11-2282/P
Volume 33,Issue 5,2007 Table of Contents
2007, 33(5):3-11.
DOI: 10.7519/j.issn.1000-0526.2007.5.001
Abstract:
The observations and investigations for macroscale and microscale char acteristics of clouds and precipitations are helpful to establish their typical multiscale patterns and technological system of scientific seeding, and also s upply the important foundations for seeding schemes of precipitation enhancement. Integrated observations for a cloud and precipitation process which occurred in the experiment region of Henan Province (31.5～35°N，111～114°E) on 31 Ma rch, 2004 were carried out by means of radar, satellite, as well as airborne PMS (Particle Measurement System) and GPS (Globe Positioning System), etc. The phys ical properties of this process of cloud and precipitation are analyzed. This ra infall process, ranged from small to middme level, was caused by a typical cold front with a trough. There appeared a front cloud system with a trough at its re ar part from the GEOS satellite image. The cold front at the surface was located at the head of the cloud belt. The PPI (Plan Position Indicator) radar echo dis played a narrow and long echo belt with a not very large intensity, while the RH I (Range Height Indicator) echo showed that the average altitude of cloud top wa s 5～6km. The radar echo was almost uniform except for some individual echo clu sters whose intensity ranged from 20 to 30 dBz, and there was an obvious br ight belt of 0℃. The main clouds formed precipitation were altocumulus (Ac) above th e front and cumulostratus (Sc) below which contained abundant liquid water. The maximum liquid water contents in Ac were 0.072g/m3 and 0.086g/m3 at the height of 4340 m and 3670 m, respectively, where temperatures were -4.8℃ and 0℃, while the maximum liquid water content in Sc under Ac was 9*10-8g?cm- 3 where temperature was 0℃. Before formation of precipitation, the spectral shape of parti cles was singlepeak and the particle diameters varied from 5 to 10 μm. The co ncentration of large particles was very low, less then 0.1cm-3, with an inc ontinuous distribution. With the development of microphysical processe and precipitati on formation, the spectral shape turned to doublepeak or multipeak, and the particle concentrations and their diameters increased obviously.
The observations and investigations for macroscale and microscale char acteristics of clouds and precipitations are helpful to establish their typical multiscale patterns and technological system of scientific seeding, and also s upply the important foundations for seeding schemes of precipitation enhancement. Integrated observations for a cloud and precipitation process which occurred in the experiment region of Henan Province (31.5～35°N，111～114°E) on 31 Ma rch, 2004 were carried out by means of radar, satellite, as well as airborne PMS (Particle Measurement System) and GPS (Globe Positioning System), etc. The phys ical properties of this process of cloud and precipitation are analyzed. This ra infall process, ranged from small to middme level, was caused by a typical cold front with a trough. There appeared a front cloud system with a trough at its re ar part from the GEOS satellite image. The cold front at the surface was located at the head of the cloud belt. The PPI (Plan Position Indicator) radar echo dis played a narrow and long echo belt with a not very large intensity, while the RH I (Range Height Indicator) echo showed that the average altitude of cloud top wa s 5～6km. The radar echo was almost uniform except for some individual echo clu sters whose intensity ranged from 20 to 30 dBz, and there was an obvious br ight belt of 0℃. The main clouds formed precipitation were altocumulus (Ac) above th e front and cumulostratus (Sc) below which contained abundant liquid water. The maximum liquid water contents in Ac were 0.072g/m3 and 0.086g/m3 at the height of 4340 m and 3670 m, respectively, where temperatures were -4.8℃ and 0℃, while the maximum liquid water content in Sc under Ac was 9*10-8g?cm- 3 where temperature was 0℃. Before formation of precipitation, the spectral shape of parti cles was singlepeak and the particle diameters varied from 5 to 10 μm. The co ncentration of large particles was very low, less then 0.1cm-3, with an inc ontinuous distribution. With the development of microphysical processe and precipitati on formation, the spectral shape turned to doublepeak or multipeak, and the particle concentrations and their diameters increased obviously.
2007, 33(5):12-19.
DOI: 10.7519/j.issn.1000-0526.2007.5.002
Abstract:
Using nonhydrostatic mesoscale numerical model MM5V3 to conduct simula tion for 3 “YaAnTianLou" cases, special analysis is made to see the impact of bou ndary layer (BL) parameterization scheme MRF on the maximum intensity of rainfall and the distribution of rain area. The results show that MRF scheme has good for ecast effect, and can describe the zonalvertical circulation structure when ra instorm occurs in Ya'an; Under the condition of complex topography, the role of BL is very important, especially where the precipitation has obvious daily chang e.
Using nonhydrostatic mesoscale numerical model MM5V3 to conduct simula tion for 3 “YaAnTianLou" cases, special analysis is made to see the impact of bou ndary layer (BL) parameterization scheme MRF on the maximum intensity of rainfall and the distribution of rain area. The results show that MRF scheme has good for ecast effect, and can describe the zonalvertical circulation structure when ra instorm occurs in Ya'an; Under the condition of complex topography, the role of BL is very important, especially where the precipitation has obvious daily chang e.
2007, 33(5):20-26.
DOI: 10.7519/j.issn.1000-0526.2007.5.003
Abstract:
Based on the data from the surface and upper air observations in Wuhan and numer ical synoptic prediction data from EC during May 1st 2001 to December 31st 2004, the different samples are made. Based on SVM method, crossvalidations are per formed with randomly samples to find the samples with best factors and optimizat ion parameter g, then the models of the cloud amount forecast are built. The sta bility, the forecast and generalization ability of the models are also revealed by crossvalidations. The results of test and realtime forecast show the fore cast ability of the cloud amount forecast models by SVM.
Based on the data from the surface and upper air observations in Wuhan and numer ical synoptic prediction data from EC during May 1st 2001 to December 31st 2004, the different samples are made. Based on SVM method, crossvalidations are per formed with randomly samples to find the samples with best factors and optimizat ion parameter g, then the models of the cloud amount forecast are built. The sta bility, the forecast and generalization ability of the models are also revealed by crossvalidations. The results of test and realtime forecast show the fore cast ability of the cloud amount forecast models by SVM.
2007, 33(5):27-35.
DOI: 10.7519/j.issn.1000-0526.2007.5.004
Abstract:
Based on the NCEPNCAR data and the observational data on March 910, 2006, a diagnostic analysis is conducted for the development of Mongolia cyclone inducing the severe dust storm. The results show that highlevel anticyclonic flows contribute to development of the wave energy, and make the explosive cyclon e. Although vorticity advection and thermal advection are important to the cyclo ne development, vorticity advection is weaker than thermal advection at the firs t stage of cyclone development. The baroclinicity in the lower troposphere stren gthens significantly with frontolysis at the rear part of the cyclone and the fr ontogenesis of foreside the cyclone, which is helpful for release of available p otential energy, production of kinetic energy and the development of the cyclone . In addition, the potential vorticity analysis indicates that the cyclone devel opment is related to the activities of cold air, and there exist distinct intera ctions between systems of the upper and lower troposphere, but the role of water vapour and release of potential heat is not obvious. The mechanism of developme nt of cyclone is quite different from that of other cyclones associated with the summer precipitation in China.
Based on the NCEPNCAR data and the observational data on March 910, 2006, a diagnostic analysis is conducted for the development of Mongolia cyclone inducing the severe dust storm. The results show that highlevel anticyclonic flows contribute to development of the wave energy, and make the explosive cyclon e. Although vorticity advection and thermal advection are important to the cyclo ne development, vorticity advection is weaker than thermal advection at the firs t stage of cyclone development. The baroclinicity in the lower troposphere stren gthens significantly with frontolysis at the rear part of the cyclone and the fr ontogenesis of foreside the cyclone, which is helpful for release of available p otential energy, production of kinetic energy and the development of the cyclone . In addition, the potential vorticity analysis indicates that the cyclone devel opment is related to the activities of cold air, and there exist distinct intera ctions between systems of the upper and lower troposphere, but the role of water vapour and release of potential heat is not obvious. The mechanism of developme nt of cyclone is quite different from that of other cyclones associated with the summer precipitation in China.
2007, 33(5):36-41.
DOI: 10.7519/j.issn.1000-0526.2007.05.005
Abstract:
Tropical cyclones Bilis and Kaemi have similar track and construction but their intensity of rainfall are very different. Their circulation and phy sical fields are compared and the conclusions show that the rainfall of landing tropical cycl ones is associated with the prevailing northeast air flow at upper level and i ntensified southwest monsoon. The low level convergence, high level divergence, ascending motion, water vapor transport and instability energy for these two tr opical cyclones over South China were significantly different under the differen t patterns, resulting in different rainstorms during the two tropical cyclones.
Tropical cyclones Bilis and Kaemi have similar track and construction but their intensity of rainfall are very different. Their circulation and phy sical fields are compared and the conclusions show that the rainfall of landing tropical cycl ones is associated with the prevailing northeast air flow at upper level and i ntensified southwest monsoon. The low level convergence, high level divergence, ascending motion, water vapor transport and instability energy for these two tr opical cyclones over South China were significantly different under the differen t patterns, resulting in different rainstorms during the two tropical cyclones.
2007, 33(5):42-48.
DOI: 10.7519/j.issn.1000-0526.2007.5.006
Abstract:
Due to the enormous disaster of the heavy rainfall in Hunan and Guangd ong, etc., caused by the severe landing tropical storm Bilis, the process is inv estigated based on the dense observational data, the satellite data, NCEP/NCAR r eanalysis data and products of MM5. The results show that the tropical depress i on moved tardily owning to the surrounding of the west Pacific subtropical high, north mainland high, Tibetan high and low latitudes high. The southeast stream from the southwest part of the subtropical high and the southwest monsoon stream transported the vapor to the depression continuously, which was propitious to t he maintenance of its intensity. It is found that plenteous vapor, intense verti cal convection and strong convergence of the low level stream have advantage for the heavy rainfall by analyzing MM5 numerical forecast products and physical factor field.
Due to the enormous disaster of the heavy rainfall in Hunan and Guangd ong, etc., caused by the severe landing tropical storm Bilis, the process is inv estigated based on the dense observational data, the satellite data, NCEP/NCAR r eanalysis data and products of MM5. The results show that the tropical depress i on moved tardily owning to the surrounding of the west Pacific subtropical high, north mainland high, Tibetan high and low latitudes high. The southeast stream from the southwest part of the subtropical high and the southwest monsoon stream transported the vapor to the depression continuously, which was propitious to t he maintenance of its intensity. It is found that plenteous vapor, intense verti cal convection and strong convergence of the low level stream have advantage for the heavy rainfall by analyzing MM5 numerical forecast products and physical factor field.
2007, 33(5):49-55.
DOI: 10.7519/j.issn.1000-0526.2007.5.007
Abstract:
The cold airstream snowfall weather events occurring in Shandong Penin sula have different characteristics from other precipitation processes. Two cont inuous heavy snowfall courses in northern Shandong Peninsula in December 2005 we re analyzed. It can be seen from the conventional radar data that the top layer of echo is 3 km, which reflects the low level characteristics of cold airstream courses. The simulation results by WRF mesoscale numerical model show tha t the cold airstream weather has a close relationship with the structure of low level atmosp here. The cold airstream of 850hPa layer has a positive correlation with ground precipitation. Vertical distributions of cloud water, cloud graupel water and ve rtical velocity further approved the low level characteristics of cold airstream precipatition.
The cold airstream snowfall weather events occurring in Shandong Penin sula have different characteristics from other precipitation processes. Two cont inuous heavy snowfall courses in northern Shandong Peninsula in December 2005 we re analyzed. It can be seen from the conventional radar data that the top layer of echo is 3 km, which reflects the low level characteristics of cold airstream courses. The simulation results by WRF mesoscale numerical model show tha t the cold airstream weather has a close relationship with the structure of low level atmosp here. The cold airstream of 850hPa layer has a positive correlation with ground precipitation. Vertical distributions of cloud water, cloud graupel water and ve rtical velocity further approved the low level characteristics of cold airstream precipatition.
2007, 33(5):56-61.
DOI: 10.7519/j.issn.1000-0526.2007.5.008
Abstract:
The temporal and spatial distribution of the real time synoptic systems, the phy sics factors and the radar echo characteristics all indicated that a heavy rain process will occur in Wuhan singlestation and eastern Hubei province in 24 hou rs, but it is proved a false prediction. In order to find the reasons, some phys ics factors are diagnosed by using T213 numerical prediction products. Based on the physical variables, an analysis whether the heavy rain will occur in Wuhan s inglestation, and even in eastern Hubei Province is made. The results show tha t many physical factors did not consist with the forecast that a heavy rain proc ess will occur in the eastern Hubei province and Wuhan singlestation. For exam ple, without the energy front zone, the moisture front zone and the moisture con vergence, the rainfall synoptic system won't develop and intense. Thus the regional heavy rain won't occur. The vorticity advection of Wuhan sing lestation appears positive value at low level and negative value at high lev el. Such configurations have no dynamic effects. Vertical speed indicates that t here are downdraft at the whole upper layer of the singlesatation. All these p ositions cannot offer the important conditions for dynamic instability. Ra shows that moisture flux divergences are strong at upper troposphere of Wuhan single station and rf is in a low value. K index does not reach at 35℃ but dec rease day by day. Those physics values cannot trigger secondary circulation of s inglestation. So no heavy rains occur in Wuhan.
The temporal and spatial distribution of the real time synoptic systems, the phy sics factors and the radar echo characteristics all indicated that a heavy rain process will occur in Wuhan singlestation and eastern Hubei province in 24 hou rs, but it is proved a false prediction. In order to find the reasons, some phys ics factors are diagnosed by using T213 numerical prediction products. Based on the physical variables, an analysis whether the heavy rain will occur in Wuhan s inglestation, and even in eastern Hubei Province is made. The results show tha t many physical factors did not consist with the forecast that a heavy rain proc ess will occur in the eastern Hubei province and Wuhan singlestation. For exam ple, without the energy front zone, the moisture front zone and the moisture con vergence, the rainfall synoptic system won't develop and intense. Thus the regional heavy rain won't occur. The vorticity advection of Wuhan sing lestation appears positive value at low level and negative value at high lev el. Such configurations have no dynamic effects. Vertical speed indicates that t here are downdraft at the whole upper layer of the singlesatation. All these p ositions cannot offer the important conditions for dynamic instability. Ra shows that moisture flux divergences are strong at upper troposphere of Wuhan single station and rf is in a low value. K index does not reach at 35℃ but dec rease day by day. Those physics values cannot trigger secondary circulation of s inglestation. So no heavy rains occur in Wuhan.
2007, 33(5):62-68.
DOI: 10.7519/j.issn.1000-0526.2007.5.009
Abstract:
Using CINRADSA Doppler radar data in Fuyang, as well as weather cha rt, and the observation data at upperair and surface, a severe storm weather p rocess occurring in the northern region of Huaihe River on July 16, 2005 is anal yzed. The results show that this is a severe convective weather process with cat astrophic gale, rainstorm and local hailstone，and it was caused by a bow meso β scale squall line echo belt，which was triggered by arc gust front in the ear lier time. Further, the dry cold air into the cloud region at the middlelevel i ntensify the downdraft and the lowerlevel outflow, and then the gust front was formed. On the other hand，an initial attempt to do nowcasting was made in terms of the synthetical application of various radar products.
Using CINRADSA Doppler radar data in Fuyang, as well as weather cha rt, and the observation data at upperair and surface, a severe storm weather p rocess occurring in the northern region of Huaihe River on July 16, 2005 is anal yzed. The results show that this is a severe convective weather process with cat astrophic gale, rainstorm and local hailstone，and it was caused by a bow meso β scale squall line echo belt，which was triggered by arc gust front in the ear lier time. Further, the dry cold air into the cloud region at the middlelevel i ntensify the downdraft and the lowerlevel outflow, and then the gust front was formed. On the other hand，an initial attempt to do nowcasting was made in terms of the synthetical application of various radar products.
2007, 33(5):69-76.
DOI: 10.7519/j.issn.1000-0526.2007.5.010
Abstract:
Using conventional observational data ,satellite images, Dopper radar echo and NECP data, the causality of the strong convective severe sand dust storm in the south of Hebei on May 10,2005 is discussed. The results show that the v ertical structure of cold advection in the upper air and the warm advection in t he lower level, and increasing temperature at afternoon provided the advantageou s thermal condition. Strong surface winds were mainly caused by a squall line ah ead of the cold front which showed as a arc echo, the surface mesoscale converge nce line is very important to the squall line. Meanwhile, the development of upp er level jet and strong downward transport of momentum by the sinking branch o f the upper level jet's secondary circulation are also important for the formatio n of strong surface winds. The dust devil occurred at the coupled area of high/l ow level jets and the superposition of the positive helicity value at 700hPa and highenergy tongue and the higher gradient of the helicity's positive value at 300hPa, the magnitude of the tropospheric helicity is useful for the prediction of dust devil events.
Using conventional observational data ,satellite images, Dopper radar echo and NECP data, the causality of the strong convective severe sand dust storm in the south of Hebei on May 10,2005 is discussed. The results show that the v ertical structure of cold advection in the upper air and the warm advection in t he lower level, and increasing temperature at afternoon provided the advantageou s thermal condition. Strong surface winds were mainly caused by a squall line ah ead of the cold front which showed as a arc echo, the surface mesoscale converge nce line is very important to the squall line. Meanwhile, the development of upp er level jet and strong downward transport of momentum by the sinking branch o f the upper level jet's secondary circulation are also important for the formatio n of strong surface winds. The dust devil occurred at the coupled area of high/l ow level jets and the superposition of the positive helicity value at 700hPa and highenergy tongue and the higher gradient of the helicity's positive value at 300hPa, the magnitude of the tropospheric helicity is useful for the prediction of dust devil events.
2007, 33(5):77-82.
DOI: 10.7519/j.issn.1000-0526.2007.5.011
Abstract:
Based on meteorological observational data and FY2C TBB，a typical mes oscale con vective complex in South China on May 6, 2006 was analyzed. It shows that the su rface cold air movement and the couple of high and low level jets are the keys t o the formation and development of MCC under the unstable and plentiful vapor co nditions. The trumpetshape landform and the temperature change of underlay als o contribute to its evolution. A squall line in MCC was monitored by using termi nal Doppler radar and AWOS, and the value of lowlevel wind shear was calculate d to provide for Guangzhou Baiyun airport.
Based on meteorological observational data and FY2C TBB，a typical mes oscale con vective complex in South China on May 6, 2006 was analyzed. It shows that the su rface cold air movement and the couple of high and low level jets are the keys t o the formation and development of MCC under the unstable and plentiful vapor co nditions. The trumpetshape landform and the temperature change of underlay als o contribute to its evolution. A squall line in MCC was monitored by using termi nal Doppler radar and AWOS, and the value of lowlevel wind shear was calculate d to provide for Guangzhou Baiyun airport.
2007, 33(5):83-88.
DOI: 10.7519/j.issn.1000-0526.2007.5.012
Abstract:
Based on FY-2C meteorological satellite data and several physicsfield s calculated by NCEP/NCAR reanalysis data, the causation of the heavy rainfall event on August 16, 2005 in Tianjin is analyzed. This event occurred in a cold front with trough. And the infrequent rainfall was produced by the reasonable allocation o f the trough and the subtropical high in the middle troposphere, the shear line in the low troposphere, the incursion of the cold air in the surface, the strong instability energy in the lower / middle troposphere and the sufficient water v apor. The mesoscale characteristics of the event are associated with the mesosca le convective cloud clusters. At the same time, another convective cloud cluster s with weak precipitation but strong convection in the northeastern Heb ei Province, Beijing and Tianjin on the 15th are compared and analyzed. There are some differences between them in environmental conditions of their formation a nd development. It could provide some forecasting information for two kinds of weat her in the future.
Based on FY-2C meteorological satellite data and several physicsfield s calculated by NCEP/NCAR reanalysis data, the causation of the heavy rainfall event on August 16, 2005 in Tianjin is analyzed. This event occurred in a cold front with trough. And the infrequent rainfall was produced by the reasonable allocation o f the trough and the subtropical high in the middle troposphere, the shear line in the low troposphere, the incursion of the cold air in the surface, the strong instability energy in the lower / middle troposphere and the sufficient water v apor. The mesoscale characteristics of the event are associated with the mesosca le convective cloud clusters. At the same time, another convective cloud cluster s with weak precipitation but strong convection in the northeastern Heb ei Province, Beijing and Tianjin on the 15th are compared and analyzed. There are some differences between them in environmental conditions of their formation a nd development. It could provide some forecasting information for two kinds of weat her in the future.
2007, 33(5):89-93.
DOI: 10.7519/j.issn.1000-0526.2007.05.013
Abstract:
Summer floods and droughts from 1951 to 2006 in Chongqing and East Sich uan are analyzed here by using Z index. It shows that droughts are popular from the end of 1950s to early 1970s, 2 of the 3 most heavy years occur during this peri od. There are both droughts and floods from the end of 1970s to 2003 ，but flood s are more common. 2006 is the most serious drought year in these 56 years from 1951 to 2006. Relation analyses between SST and Z index shows that there exists good relativity between Z index and SST during January and March. Z index has ob viously positive relativity with SST in eastern and medial equatorial pacific oc ean. In heavy floods year SST anomalies are prominently positive. On contrast i n droughts years, SST anomalies are obviously negative. Negative anomalies from January and March are contributable for the serious droughts in 2006.
Summer floods and droughts from 1951 to 2006 in Chongqing and East Sich uan are analyzed here by using Z index. It shows that droughts are popular from the end of 1950s to early 1970s, 2 of the 3 most heavy years occur during this peri od. There are both droughts and floods from the end of 1970s to 2003 ，but flood s are more common. 2006 is the most serious drought year in these 56 years from 1951 to 2006. Relation analyses between SST and Z index shows that there exists good relativity between Z index and SST during January and March. Z index has ob viously positive relativity with SST in eastern and medial equatorial pacific oc ean. In heavy floods year SST anomalies are prominently positive. On contrast i n droughts years, SST anomalies are obviously negative. Negative anomalies from January and March are contributable for the serious droughts in 2006.
14 Causality of Temperature Differences Between AWS and Manual
Observations in Central Part of China
2007, 33(5):94-99.
DOI: 10.7519/j.issn.1000-0526.2007.5.014
Abstract:
The Automated Surface Observing System is currently replacing conventi onal observations in China. There are differences between the old and new measur ing systems. From a climatological viewpoint，it probably causes the errors when developing the homogeneous datasets and investigating climatic change，and anal yzing the extreme weather events. So it is necessary to compare the data from th e two systems. By means of computing the annual average differences of 21 weathe r stations in the Central China in 2005, and sorting analysis hourly data of 6 national climate stations according to cloud amount，wind speed, day and night, the differences in sitecharacteristics, solar radiation（IR cooling in night）, instrument system and observing practice are considered the main factors. It is showed that the annual average difference of temperature is almost within ±0.2 ℃. Among the abovementioned four factors, the instrument bias plays a part ro le，about 0.1℃ at most stations，the bias about local effect and observing prac tice are very little，but the bias of radiation is the largest.
The Automated Surface Observing System is currently replacing conventi onal observations in China. There are differences between the old and new measur ing systems. From a climatological viewpoint，it probably causes the errors when developing the homogeneous datasets and investigating climatic change，and anal yzing the extreme weather events. So it is necessary to compare the data from th e two systems. By means of computing the annual average differences of 21 weathe r stations in the Central China in 2005, and sorting analysis hourly data of 6 national climate stations according to cloud amount，wind speed, day and night, the differences in sitecharacteristics, solar radiation（IR cooling in night）, instrument system and observing practice are considered the main factors. It is showed that the annual average difference of temperature is almost within ±0.2 ℃. Among the abovementioned four factors, the instrument bias plays a part ro le，about 0.1℃ at most stations，the bias about local effect and observing prac tice are very little，but the bias of radiation is the largest.
2007, 33(5):100-104.
DOI: 10.7519/j.issn.1000-0526.2007.5.015
Abstract:
Using the monthly precipitation and temperature dataset from 59 statio ns over Shanxi Province, and the 500hPa height data in North hemisphere and sea surface temperature over 10°S～50°N、120°E～80°W in North Pacific during 196 1-2005, first of all, the index which represent the drought grade in Shanxi Prov ince were defined; secondly, the climatic variability and anterior signals of dr ought in Shanxi were analyzed by using the triple splinefunction and power spectrum. The results show that the drought exhibits a statistically significant interdecadal variability and interannual timescale variabilities with near 2 ye ar, 3.5 year and 5.6 year periods. Based on this analysis, a Huabei predicting drought model on an integration of multiscale was improved and modulated and a series of prediction results were p rooftested in months and seasons. By analyzing the forecast of drought grade in months and seasons during 2000-2005, it shows that the modeling techni que catches the change in drought well and exhibits a higher prediction skill.
Using the monthly precipitation and temperature dataset from 59 statio ns over Shanxi Province, and the 500hPa height data in North hemisphere and sea surface temperature over 10°S～50°N、120°E～80°W in North Pacific during 196 1-2005, first of all, the index which represent the drought grade in Shanxi Prov ince were defined; secondly, the climatic variability and anterior signals of dr ought in Shanxi were analyzed by using the triple splinefunction and power spectrum. The results show that the drought exhibits a statistically significant interdecadal variability and interannual timescale variabilities with near 2 ye ar, 3.5 year and 5.6 year periods. Based on this analysis, a Huabei predicting drought model on an integration of multiscale was improved and modulated and a series of prediction results were p rooftested in months and seasons. By analyzing the forecast of drought grade in months and seasons during 2000-2005, it shows that the modeling techni que catches the change in drought well and exhibits a higher prediction skill.
2007, 33(5):105-110.
DOI: 10.7519/j.issn.1000-0526.2007.5.016
Abstract:
By means of the climate compilation data from 1971 to 2000 at meteorol ogical stations, the natural geography and ecological environmental conditions o f fourmajorhuaimedicine (Chinese jam, rehmannia glutinosa, rehmannia rou t, c hrysanthemum flower) are investigated. The agroclimatic resources, suc h as light , heat and water are analyzed and evaluated. Comparing with the climate data and ecological environment in planting areas around, the results show that it supp lies a superexcellent growing environment for famous quality of fourmajorhua i medicine in Jiaozuo area. Finally, some corresponding measures are given to the sustainable development of fourmajorhuai medicine production.
By means of the climate compilation data from 1971 to 2000 at meteorol ogical stations, the natural geography and ecological environmental conditions o f fourmajorhuaimedicine (Chinese jam, rehmannia glutinosa, rehmannia rou t, c hrysanthemum flower) are investigated. The agroclimatic resources, suc h as light , heat and water are analyzed and evaluated. Comparing with the climate data and ecological environment in planting areas around, the results show that it supp lies a superexcellent growing environment for famous quality of fourmajorhua i medicine in Jiaozuo area. Finally, some corresponding measures are given to the sustainable development of fourmajorhuai medicine production.
2007, 33(5):111-117.
DOI: 10.7519/j.issn.1000-0526.2007.5.017
Abstract:
In order to improve the ability to use the products of T213 model，the performance of T213 model for 96hr mediumrange numerical forecasting was ver i fied during the period of Dec. 2006 to Jan.2007comparing with ECMWF model and Ja pan model. The result shows that the three models have good performances for evo lvement and major adjustment of circulation pattern in Asia middle and high lati tude area, therefore, they can forecast the severe disaster weathers ahead. By c o mparing three models, the product of ECMWF model predict well for forecasting of westerly index, temperature of 850hPa and southern trough, but there are some s ystem errors among the three model in forecasting temperature of 850hPa. Japan m odel is much better in forecasting surface pressure than T213 and ECMWF model.
In order to improve the ability to use the products of T213 model，the performance of T213 model for 96hr mediumrange numerical forecasting was ver i fied during the period of Dec. 2006 to Jan.2007comparing with ECMWF model and Ja pan model. The result shows that the three models have good performances for evo lvement and major adjustment of circulation pattern in Asia middle and high lati tude area, therefore, they can forecast the severe disaster weathers ahead. By c o mparing three models, the product of ECMWF model predict well for forecasting of westerly index, temperature of 850hPa and southern trough, but there are some s ystem errors among the three model in forecasting temperature of 850hPa. Japan m odel is much better in forecasting surface pressure than T213 and ECMWF model.
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