2011, 16(3):255-272. DOI: 10.3878/j.issn.1006-9585.2011.03.01
Abstract:The geopotential height, wind field(u, v, w), temperature, relative humidity, maximum temperature, and SST fields in the ECMWF reanalysis data sets and the observational precipitation data in China are used to study the dynamic climate features and the evolution of subtropical high over the northwestern Pacific in July. Two processes which describe the south and north positions of subtropical high are defined (south or north position lasting for more than six days is defined as one process) and the correspondence composite analysis are completed. The results show that the intraseasonal oscillation is obvious both in the south and north processes, and the most typical oscillation occurs in July. Corresponding to the south and north processes of the subtropical high, there are evident different features and evolutions in atmospheric circulation, the distribution of precipitation, the maximum temperature in China, and the SST anomaly in the northwestern Pacific. This means that it is necessary to study and understand the dynamic characteristic of weather and climate based on the variability of the atmospheric system even though just in July as a short period. Through the analysis of process evolutions, some interesting results on the premonition characteristic, variation features during and after the north, south processes of subtropical high are indicated, which are undiscovered in previous studies.
2011, 16(3):273-279. DOI: 10.3878/j.issn.1006-9585.2011.03.02
Abstract:The Support Vector Machine (SVM) is a new machine learning method based on the statistical learning theory and it is very useful to solve nonlinear problems of short time series. Based on the daily observations obtained from the Nanjing meteorological station and the daily measured contamination data obtained from the Nanjing environmental quality monitoring station from 2004 to 2007，prediction models of hazeday classification and visibility at 1400 LST in haze days in Nanjing are built by the SVM method. The results show that the threat scores（Ts）of hazeday classification forecast are all over 04 and the precision of visibility at 1400 LST in haze days can reach 86% by considering 3 km as the error bounds. Otherwise，the forecast models which are revised by the new data at 0800 LST of that day are better than the beginning forecast models according to the results. Both SVM forecast models perform satisfactorily and can refer references to real business.
2011, 16(3):280-288. DOI: 10.3878/j.issn.1006-9585.2011.03.03
Abstract:Based on the annual Emission Database for Global Atmospheric Research （EDGAR，Version 3.2） CO emissions data, the preliminary mechanism of the extreme center coming into being and related transport process transported upwards by deep convection and confined by the anticyclonic circulation in the North Hemisphere in summer 2006 is investigated by using a Lagrangian particle transport and dispersion model FLEXPART containing a simple convective parameterization. There is a good agreement in the temporal trend although a litter difference (the volume fraction can reach 2×10-8－3×10-8) between simulated CO and observations derived from satellite is obtained over Asia monsoon region possibly due to the uncertainty of CO emissions. The authors investigate the respective roles of large scale transport and convection in determining CO maximum in Upper Troposphere (UT) in the Asian monsoon region. It is found that the model can also simulate the CO distribution characteristic even only droved by the large scale wind fields. But the enhanced results can be obtained with the consideration of convection. The results show that convection does not have a significant impact on the CO budget comparing with the large scale circulation. The maximum CO value regions in UT in the Asian monsoon areas in summer mainly have an origination from the atmosphere boundary layer surface from the north of Indian Peninsula, the middle of Africa，and the northeast part of China. In Asian monsoon regions, two main transportation processes of CO account for the exceptional distribution of CO in upper troposphere. On the one hand, high density CO in the lower troposphere can be lifted upwards into UT quickly, even can be advected vertically further to the altitudes near the tropopause (about 16 km) by large scale，and mesoscale and small scale convective circulation, and then, much of the CO is then advected in the upper troposphere southwestward with the cross equatorial Hadley flow. On the other hand, the eastward and poleward transportations in the middle and lower troposphere turn the central southern India, Arabia, even the middle part of Africa into origins for long distance transport of CO in the Asian monsoon regions.
2011, 16(3):289-300. DOI: 10.3878/j.issn.1006-9585.2011.03.04
Abstract:By employing the NCEP/NCAR reanalysis datasets, the characteristic of the torrential rain event occurred in Shandong Province is analyzed. The results show that the interaction between mid and low latitude systems play an important role in the occurrence of the torrential rain event. The feature of dry air intrusion is also analyzed, it is different from the “7.18” torrential rain occurred in Jinan and mainly presents a zonal intrusion characteristic. Through the diagnostic analysis of pseudo-equivalent potential temperature（θse）, it is found that the dry air intrusion is advantageous to the formation and maintenance of frontal zone, in addition, the dry air intrusion can cause the increase of convective instability which is useful to the maintenance and development of convection. The analysis of MPV (Moist Potential Vorticity) shows that the probably mechanism of the dry intrusion is that the high potential vorticity descends from the upper troposphere to the lower level, therefore, the dry air intrusion is one kind of the high MPV forcing.
2011, 16(3):301-309. DOI: 10.3878/j.issn.1006-9585.2011.03.05
Abstract:The distribution of cirrus clouds over China is presented using the Earthorbiting CloudAerosol Lidar with Orthogonal Polarization (CALIOP) Level 25 km (horizontal resolution) cloud layer product from June 2006 to May 2008. The three quality control standards based on cirrus climatologies can be effectively used to eliminate the cirrus false identifications in this product. From the analysis of cirrus cloud horizontal distribution, the authers attribute the highest occurrence frequency of cirrus clouds of about 60% in the south of China near Intertropical Convergence Zone (ITCZ) to the strongly rising air and rich water vapor. The terraininduced cirrus clouds produced by uplifted relatively warm and moist air on the QinghaiXizang Plateau cause the relatively high occurrence frequency of about 30%－40% on the northeast slope of QinghaiXizang Plateau. The migrations of ITCZ and monsoon induce the seasonal latitudinal movement of cirrus over China, and the relatively high cirrus on the northeast slope of QinghaiXizang Plateau relatively which occurs in winter and spring as well. The latitudinal variation of vertical distribution of cirrus displays that the cirrus clouds at low-latitude center around 16 km due to the limit of tropopause. The analysis shows that the horizontal distribution of multilayered cirrus cloud systems with different kinds of cloud is closely associated with the latitudinal distribution of different kinds of cloud. In addition to the multilayered cirrus cloud systems occurring with cirrus, the relatively high value on the northeast of Qinghai-Xizang Plateau is mainly contributed to the occurrence of systems with high altocumulus.
2011, 16(3):310-321. DOI: 10.3878/j.issn.1006-9585.2011.03.06
Abstract:Using the NCEP/NCAR reanalysis Surface Sensible Heat Flux (SSHF) dataset during 1951－2000, the general features of SSHF distribution over central and eastern Asia are analyzed. It is found that there are three areas with higher values of SSHF in North China, Northwest China, and India, whereas the areas with lower SSHF values are located in Northeast China and South China, and strong interannual variability of SSHF can be found around 30°N over eastern China, Tibetan Plateau region, and India. The spatial and temporal distribution of SSHF over central and eastern Asia has been further investigated based on the REOF（Rotated Empirical Orthogonal Function） method and the relationship between spring SSHF and summer precipitation over China has also been examined. The significant correlations can be found between summer precipitation anomalies over Yellow River and Huaihe River basin and SSHF anomalies over about 30°N in eastern part of China, while the summer precipitation anomalies in the Yangtze River are closely correlated with the SSHF anomalies over the Tibetan Plateau and India region. Further analysis shows that, the anomalies of spring SSHF over about 30°N in eastern part of China are accompanied by atmospheric circulation anomalies in southeastern and southwestern China, which can result in the anomalies of southwest wind intensity, and the summer precipitation anomalies. The anomalies of SSHF in India are associated with the anomalies of Indian summer monsoon, which can affect the East Asian summer circulation and precipitation in China through teleconnection mechanism.
2011, 16(3):322-328. DOI: 10.3878/j.issn.1006-9585.2011.03.07
Abstract:Daily weather records from private diaries are important proxy data for reconstructing historical precipitation. The authors extracted daily weather records from “Diary of Weng Tonghe” and calculated the monthly rain/snow days using these records. The annual and summer precipitation in Beijing during 1860－1897 was reconstructed using the conversion functions relating precipitation with rain/snow days. Finally, by integrating the reconstruction with the instrumental data and the reconstruction from Sunshine Rainfall Records (SRR), the precipitation during 1860－1897 in Beijing was reestimated. The results show: (1) The reconstruction based on the rain/snow days from “Diary of Weng Tonghe” is generally reliable and the reconstructed annual precipitation was about 611.5 mm; however, the precipitation in relative flood years was underestimated by the conversion functions; (2) the reestimated annual precipitation was about 701.3 mm, which might be more than that in the later half of 20th century; (3) the instrumental precipitation record in 1891 may be more than the actual value and the instrumental precipitation record in 1895 may be lower than the actual value; dry-wet grades in 1869, 1863, 1885, 1889, and 1887 may be not consistent with actual conditions. This research demonstrates the daily weather records from private diaries have great potential to reconstruct historical precipitation, but it is worthy to note that lower biases existed in the present reconstruction.
2011, 16(3):329-336. DOI: 10.3878/j.issn.1006-9585.2011.03.08
Abstract:In view of the characteristics of the arid climate and simple land surface types in the northwest of China, Complementary Relationship Model (CRM) is discussed to evaluate its precision in calculation. By using the observational data from Yucheng experimental station which is located in Shangdong Province, the influence of vegetation diversity on CRM is analysed. The result shows that the distributions of vegetation diversity and no in-phase phenology are two important reasons that cause large-scale advection parameter, a primary parameter in CRM, to change with the seasons. At last, CRM is applied in the northwest of China. The real evapotranspiration from CRM is essentially uniform with the distribution of land surface types, and presents complementary characteristics compared with that from the 20 cm caliber evaporating dish, and similar seasonal change characteristic to precipitation, temperature, and phenology.
2011, 16(3):337-346. DOI: 10.3878/j.issn.1006-9585.2011.03.09
Abstract:The underlying surface of more than 700 national meteorological stations in different historical periods is distinguished based on the MSS (MultiSpectral Scanner) images of the 1970s, TM (Thematic Mapper) images around 1990, and ETM (Enhanced Thematic Mapper) images around 2000 and 2005. The stations with apparent changes in their underlying surface and surrounding building environment are picked out and verified by telephone consultation. Based on the discriminant result, annual and seasonal change characteristics of air temperature are analyzed, and it is concluded that the change rate at air temperature of the stations “entering city” is higher than that at the other stations. The result validates the discriminant method based on RS (Remote Sensing) images, and conforms that the observed air temperature at the stations “entering city” increase more than the other stations affected by the urban circumstance.
2011, 16(3):347-352. DOI: 10.3878/j.issn.1006-9585.2011.03.10
Abstract:The frost phenophase was anaylysed with linear trend and single correlation method by using meteorological data from 33 weather stations in Qinghai Plateau. Results show that the variation trends of first frost and latest frost present regional features of delay and ahead of schedule, respectively. On the interdecadal scale, first frost was delayed while latest frost was advanced and frostfree period was extended obviously in most regions. In a few areas, a negative correlation existed between latest frost with air temperature, and a positive correlation with precipitation. In some areas, a positive correlation existed between first frost with air temperature, and had no obvious responses to precipitation. In most areas, a positive correlation existed between frostfree period with air temperature and precipitation. The comprehensive response of first frost and latest frost to climate change showed that the extened variation trends have obvious regional differences.
2011, 16(3):353-368. DOI: 10.3878/j.issn.1006-9585.2011.03.11
Abstract:Surface energy distribution, CO2 flux, surface effective radiative temperature, and soil moisture over a typical steppe prairie in Inner Mongolia, China from 1 July to 〖JP2〗30 September 2007 were simulated by using Simple Biosphere model 2 (SiB2). Based on the surface flux monitoring system data, the model was initialized and driven by using short-wave solar radiation, atmospheric long-wave radiation, vapor pressure, air temperature, wind speed，and precipitation. Then the simulated and observed turbulent flux, surface effective radiative temperature, and soil moisture were compared. The results show that: 1) SiB2 overestimated net radiation, latent heat flux, and soil heat flux by 11%, 10%, and 5%, respectively, and it underestimated sensible heat flux by 6%. 2) The simulated CO2 fluxes in July and August were consistent with the observation. But the model underestimated the CO2 flux in September by 14.2%. 3) Surface effective radiative temperature was underestimated (overestimated) in the day (night). 4) Soil moisture was estimated reasonably.
2011, 16(3):369-377. DOI: 10.3878/j.issn.1006-9585.2011.03.12
Abstract:Any regional climate resource is regarded as a kind of climate state vector from the view of climate vector, by means of rotating principal component analysis, the state vector of climate resources is calculated, on the basis of which, the light resource, heat resource, moisture， and other climatic and environmental conditions are integrated as the vector of climate resource. A comparative relationship with a crop growth model of the standard curve is established, and then one new model about the production potential of agroclimatic is put forward. Relative photosynthesis production potential, photothermal production potential，and climate production potential have been obtained, all of which prove the limitations of the classic method. The tests show that this improved relative production potential has better universality and comparability, which is suitable for comparing the crop production in different areas.
2011, 16(3):378-388. DOI: 10.3878/j.issn.1006-9585.2011.03.13
Abstract:Using the ECMWF Interim ReAnalysis (ERAInterim) data from 1989 to 2008 and the simulations from 1980 to 2019, which are produced by a chemistry-climate model, variation characteristics and trends of the tropical tropopause layer (TTL) structure are analyzed. It is found that the TTL characteristics have significant seasonal and spatial variations. The thickness of the TTL in summer and autumn is the thinnest in the Northern Hemisphere and it has the largest seasonal variability in winter in the Northern Hemisphere. ERA-Interim data indicates that the TTL temperature increased significantly in 1991 because of the Pinatubo volcanic eruption, and the temperature decreased after that from 1992 to 1995. The TTL temperature has been increasing since 1996 without considering the impact of Pinatubo volcanic eruption. In recent years the TTL is getting higher, warmer and thinner， and the stratospheric water vapor is also increasing. The chemistry〖CD*2〗climate model simulations show the same trends.
2011, 16(3):389-398. DOI: 10.3878/j.issn.1006-9585.2011.03.14
Abstract:Using the data of sunshine duration, temperature, wind speed， and precipitation from 194 basic/reference stations over China from 1951 to 2009, according to the climatic division, the whole domain of China is classified into 11 climatic regions. The authors studied the changes in annual and seasonal trends of the sunshine duration by using linear trend analysis and Morlet wavelet analysis, and analyzed the characteristics between the sunshine duration and the temperature, the wind speed, and the precipitation. It was found that the annual sunshine duration showed a significant decreasing tendency during the recent 59 years with a decreasing rate of 36.9 h·(10 a)-1. The trend variations of the annual sunshine duration in 11 climatic regions were similar with that in the whole nation, only had the difference in degree. The sunshine duration of China changed from intensive to weak in 1981. There is an obvious 7－10-year periodic oscillation for the annual sunshine duration of China before the mid 1990s. The sunshine duration of the four seasons had a bigger decreasing amplitude in the coastal areas than in the inland areas, and in the South than in the North. There was a negative correlation between the annual sunshine duration and the temperature (correlation coefficient is -0.52), but a positive correlation between the annual sunshine duration and the wind speed (correlation coefficient is 0.76), and a negative correlation between the annual sunshine duration and the precipitation (correlation coefficient is -0.27). The first two correlation coefficients and the last correlation coefficient passed 99.9% and 95% confidence levels，respectively.
2011, 16(3):399-406. DOI: 10.3878/j.issn.1006-9585.2011.03.15
Abstract:A strong global glaciation took place on the Earth in Neoproterozoic. The evidences and characteristics of the glaciation during the Neoproterozoic is reviewed first while the mechanism of the glaciation is discussed. Then the models of the “Snowball Earth” and the effects of the glaciation on early life growth are summarized. Finally, the future development trend of “Snowball Earth” is forecasted.