By using a nine-level atmospheric general circulation model developed at the Institute of Atmospheric Physics (IAP 9L AGCM), two sets of numerical experiments are carried out to investigate the influence of the Mascar...By using a nine-level atmospheric general circulation model developed at the Institute of Atmospheric Physics (IAP 9L AGCM), two sets of numerical experiments are carried out to investigate the influence of the Mascarene high (MH) and Australian high (AH) over the southern subtropics upon the East Asian summer monsoon circulation and summer precipitation in East Asia. The use of ensemble statistics is adopted to reduce the simulation errors. The result shows that with the intensification of MH, the Somali low-level jet is significantly enhanced together with the summer monsoon circulation in the tropical Asia and western Pacific region. Furthermore, the anticyclonic anomaly in the tropical western Pacific to the east of the Philippines may induce a weak East-Asia-Pacific teleconnection pattern. In the meantime, geopotential height in the Tropics is enhanced while it is reduced over most regions of mid-high latitudes, thus the northwestern Pacific subtropical high at 500 hPa extends southwestward, resulting in more rainfall in southern China arid less rainfall in northern China. A similar anomaly pattern of the atmospheric circulation systems is found in the experiment of the intensification of AH. On the other hand, because the cross-equatorial currents associated with AH are much weaker than the Somali jet, the anomaly magnitude caused by the intensification of AH is generally weak, and the influence of AH on summer rainfall in China seems to be localized in southern China. Comparison between the two sets of experiments indicates that MH plays a crucial role in the interactions of general atmospheric circulation between the two hemispheres.展开更多
The Australian farming sector is continuing to intensify, particularly within 300 km of the east and southern coastlines. In the future there will be fewer and larger farms, which will use more fertilizer, support mor...The Australian farming sector is continuing to intensify, particularly within 300 km of the east and southern coastlines. In the future there will be fewer and larger farms, which will use more fertilizer, support more stock, grow more monoculture crops, and utilise more marginal soils. This is likely to increase the major environmental impacts of soil degradation, salt, nutrient and sediment contamination of waterways, and greenhouse gas emissions. Australian national water policy continues to focus on land, stream and groundwater salinity issues, although there is now a greater recognition of the importance of nitrogen and phosphorus losses from agriculture. The general philosophy of policy for dealing with non- point source pollution has been towards a voluntary rather than regulatory approach, with state and national governments supporting a range of programs to encourage sustainable agricultural practices. A catchment (watershed) based approach, through the use of integrated catchment management plans, is the primary way that non-point source pollution is addressed at the farm and local level. At an industry level, cotton, grains, meat, sugarcane and dairy amongst others, as well as the Australian fertilizer industry, have responded to non-point source issues by investing in research and development, and developing codes of practice aimed at abating these environmental impacts. Understanding the economic, social, political and cultural contexts of farming as well as the environmental impacts of agriculture are very important in determining the appropriateness of policy responses for Australian farming systems.展开更多
The span of coordinate time series affects the determination of an optimal noise model. We analyzed position data recorded for 10 continuous Global Positioning System （GPS） sites from 1998.0 to mid-2009 on the Austr...The span of coordinate time series affects the determination of an optimal noise model. We analyzed position data recorded for 10 continuous Global Positioning System （GPS） sites from 1998.0 to mid-2009 on the Australian Plate to estimate the best noise model and thereafter obtain the true uncertainties of the velocity, employing the maximum likelihood estimation （MLE） method. MLE was employed to analyze the data in four ways. In the first two analyses, the noise was assumed to be a combination of flicker noise and white noise for the raw time series and spatially filtered time series. In the final two analyses, the spectral indices and amplitudes were simultaneously estimated for a power law noise plus white noise model for the raw time series and spatially filtered time series. We conclude that the noise model of GPS time series in Australia can be best described as the combination of flicker noise and white noise. Velocity uncertainties fall below -0.2 mm/yr when the time span exceeds -9.5 years. A comparison of noise amplitudes and maximum likelihood estimation values between the raw and spatially filtered time series suggests that traditional spatial filtering to remove common-mode errors might not be applicable to the raw time series of this region.展开更多
Five Australian wild cotton species with the delayed gland morphogenesis trait, as well as G. arboreum, G. davidsonii and four different gland genotypes of G. hirsutum, Gl2Gl2Gl3Gl3, Gl2Gl2gl3gl3, gl2gl2Gl3Gl3, and gl...Five Australian wild cotton species with the delayed gland morphogenesis trait, as well as G. arboreum, G. davidsonii and four different gland genotypes of G. hirsutum, Gl2Gl2Gl3Gl3, Gl2Gl2gl3gl3, gl2gl2Gl3Gl3, and gl2gl2gl3gl3, were used in this experiment and 10 interspecific hybrids were obtained by the crossing among them. According to the gland expression on the seeds and plants of the interspecific hybrids, the inheritance of the delayed gland morphogenesis trait of Australian wild cotton species was opened out as follows: (i) the inheritance of the delayed gland morphogenesis trait was almost the same among the 5 Australian wild cotton species, and the gene or genes which controlled this trait may be located in the same loci. (ii) The glandless seed trait of the Australian wild cotton species was dominant over the glanded seed trait of G. arboreum, a genome A species, and the seeds of interspecific hybrid F1 between them were glandless. However, it was recessive over the glanded character of展开更多
Using a global OGCM and its relevant coupledocean-atmosphere GCM with the contemporary, 6 MaBPand 14 MaBP oceanic topography, respectively, a series ofnumerical experiments are implemented in order to investi-gate the...Using a global OGCM and its relevant coupledocean-atmosphere GCM with the contemporary, 6 MaBPand 14 MaBP oceanic topography, respectively, a series ofnumerical experiments are implemented in order to investi-gate the effect of the north shift of Australian continent onthe tropical oceanic circulation, especially the formation ofthe western Pacific warm pool. The numerical experimentsof the individual OGCM forced by the modern atmosphericcirculation indicate that the closure of Indonesian passageresults in warming in the tropical Pacific Ocean and coolingin the tropical Indian Ocean; furthermore, it also results inchange in source of the Indonesian Through Flow (ITF) wa-ter, e.g. ITF mainly originates from the south Pacific at 14MaBP, but it mainly originates from the north Pacific now.The coupled model shows similar results as the individualOGCM qualitatively.展开更多
基金supported by the National Natural Science Foundation of China under Grant Nos.40233027,40075020 and 40221503
文摘By using a nine-level atmospheric general circulation model developed at the Institute of Atmospheric Physics (IAP 9L AGCM), two sets of numerical experiments are carried out to investigate the influence of the Mascarene high (MH) and Australian high (AH) over the southern subtropics upon the East Asian summer monsoon circulation and summer precipitation in East Asia. The use of ensemble statistics is adopted to reduce the simulation errors. The result shows that with the intensification of MH, the Somali low-level jet is significantly enhanced together with the summer monsoon circulation in the tropical Asia and western Pacific region. Furthermore, the anticyclonic anomaly in the tropical western Pacific to the east of the Philippines may induce a weak East-Asia-Pacific teleconnection pattern. In the meantime, geopotential height in the Tropics is enhanced while it is reduced over most regions of mid-high latitudes, thus the northwestern Pacific subtropical high at 500 hPa extends southwestward, resulting in more rainfall in southern China arid less rainfall in northern China. A similar anomaly pattern of the atmospheric circulation systems is found in the experiment of the intensification of AH. On the other hand, because the cross-equatorial currents associated with AH are much weaker than the Somali jet, the anomaly magnitude caused by the intensification of AH is generally weak, and the influence of AH on summer rainfall in China seems to be localized in southern China. Comparison between the two sets of experiments indicates that MH plays a crucial role in the interactions of general atmospheric circulation between the two hemispheres.
基金supported by the China Council for International Cooperation on Environment and Development (CCICED)
文摘The Australian farming sector is continuing to intensify, particularly within 300 km of the east and southern coastlines. In the future there will be fewer and larger farms, which will use more fertilizer, support more stock, grow more monoculture crops, and utilise more marginal soils. This is likely to increase the major environmental impacts of soil degradation, salt, nutrient and sediment contamination of waterways, and greenhouse gas emissions. Australian national water policy continues to focus on land, stream and groundwater salinity issues, although there is now a greater recognition of the importance of nitrogen and phosphorus losses from agriculture. The general philosophy of policy for dealing with non- point source pollution has been towards a voluntary rather than regulatory approach, with state and national governments supporting a range of programs to encourage sustainable agricultural practices. A catchment (watershed) based approach, through the use of integrated catchment management plans, is the primary way that non-point source pollution is addressed at the farm and local level. At an industry level, cotton, grains, meat, sugarcane and dairy amongst others, as well as the Australian fertilizer industry, have responded to non-point source issues by investing in research and development, and developing codes of practice aimed at abating these environmental impacts. Understanding the economic, social, political and cultural contexts of farming as well as the environmental impacts of agriculture are very important in determining the appropriateness of policy responses for Australian farming systems.
基金supported by the National Natural Science Foundation of China(Grant Nos.41304007,41074022)the Chinese Universities Scientific Fund(Grant No.121103)+1 种基金the Surveying and Mapping Basic Research Program of the National Administration of Surveying,Mapping and Geoinformation(Grant No.11-02-02)the China Scholarship Council and College of Science of the University of Nevada,Reno
文摘The span of coordinate time series affects the determination of an optimal noise model. We analyzed position data recorded for 10 continuous Global Positioning System （GPS） sites from 1998.0 to mid-2009 on the Australian Plate to estimate the best noise model and thereafter obtain the true uncertainties of the velocity, employing the maximum likelihood estimation （MLE） method. MLE was employed to analyze the data in four ways. In the first two analyses, the noise was assumed to be a combination of flicker noise and white noise for the raw time series and spatially filtered time series. In the final two analyses, the spectral indices and amplitudes were simultaneously estimated for a power law noise plus white noise model for the raw time series and spatially filtered time series. We conclude that the noise model of GPS time series in Australia can be best described as the combination of flicker noise and white noise. Velocity uncertainties fall below -0.2 mm/yr when the time span exceeds -9.5 years. A comparison of noise amplitudes and maximum likelihood estimation values between the raw and spatially filtered time series suggests that traditional spatial filtering to remove common-mode errors might not be applicable to the raw time series of this region.
基金This work was supported by the National Natural Science Foundation of China (Grant No. 39970467) and Zhejiang Provincial Natural Science Foundation (Grant No. 398260).
文摘Five Australian wild cotton species with the delayed gland morphogenesis trait, as well as G. arboreum, G. davidsonii and four different gland genotypes of G. hirsutum, Gl2Gl2Gl3Gl3, Gl2Gl2gl3gl3, gl2gl2Gl3Gl3, and gl2gl2gl3gl3, were used in this experiment and 10 interspecific hybrids were obtained by the crossing among them. According to the gland expression on the seeds and plants of the interspecific hybrids, the inheritance of the delayed gland morphogenesis trait of Australian wild cotton species was opened out as follows: (i) the inheritance of the delayed gland morphogenesis trait was almost the same among the 5 Australian wild cotton species, and the gene or genes which controlled this trait may be located in the same loci. (ii) The glandless seed trait of the Australian wild cotton species was dominant over the glanded seed trait of G. arboreum, a genome A species, and the seeds of interspecific hybrid F1 between them were glandless. However, it was recessive over the glanded character of
文摘Using a global OGCM and its relevant coupledocean-atmosphere GCM with the contemporary, 6 MaBPand 14 MaBP oceanic topography, respectively, a series ofnumerical experiments are implemented in order to investi-gate the effect of the north shift of Australian continent onthe tropical oceanic circulation, especially the formation ofthe western Pacific warm pool. The numerical experimentsof the individual OGCM forced by the modern atmosphericcirculation indicate that the closure of Indonesian passageresults in warming in the tropical Pacific Ocean and coolingin the tropical Indian Ocean; furthermore, it also results inchange in source of the Indonesian Through Flow (ITF) wa-ter, e.g. ITF mainly originates from the south Pacific at 14MaBP, but it mainly originates from the north Pacific now.The coupled model shows similar results as the individualOGCM qualitatively.
