Three functional models, polynomial, spectral analysis, and modified AR model, are studied and compared in fitting and predicting clock deviation based on the data sequence derived from two-way satellite time and freq...Three functional models, polynomial, spectral analysis, and modified AR model, are studied and compared in fitting and predicting clock deviation based on the data sequence derived from two-way satellite time and frequency transfer. A robust equivalent weight is applied, which controls the significant influence of outlying observations. Some conclusions show that the prediction precision of robust estimation is better than that of LS. The prediction precision calculated from smoothed observations is higher than that calculated from sampling observations. As a count of the obvious period variations in the clock deviation sequence, the predicted values of polynomial model are implausible. The prediction precision of spectral analysis model is very low, but the principal periods can be determined. The prediction RMS of 6-hour extrapolation interval is Ins or so, when modified AR model is used.展开更多
To ensure the effectiveness of the operation of artificial precipitation enhancement, a potential region for the operation should be determined in advance.As cloud microphysical measurements needed for the determinati...To ensure the effectiveness of the operation of artificial precipitation enhancement, a potential region for the operation should be determined in advance.As cloud microphysical measurements needed for the determination of the potential region of cloud seeding are not available before the operation of routine precipitation enhancement, a new method based on the growth process of ice crystal is put forward for determining the potential region using the numerical weather prediction model output.The ice supersaturation, accumulated water vapor within minus temperature layer (≥9 mm), and upward water vapor transportation are adopted as criteria to determine the potential time, height and region of cloud seeding, and the real-time radar images are applied to make decisions on the seeding commanding.The criteria and Doppler radar images are studied in a case of precipitation enhancement characterized by significant water vapor supply from the north part of a tropical cyclone in the northwest Pacific, which shows that the ocean plays a crucial role in the advection transportation of water vapor to the potential region of the coastal area.The study presents a new method to determine the potential region of precipitation enhancement using macro-physical quantities under ice crystal growth environment.The method possesses a clear physical significance and can be readily applied with the required and easily predicted parameters.展开更多
Using the conditional nonlinear optimal perturbation(CNOP) approach, sensitive areas of adaptive observation for predicting the seasonal reduction of the upstream Kuroshio transport(UKT) were investigated in the Regio...Using the conditional nonlinear optimal perturbation(CNOP) approach, sensitive areas of adaptive observation for predicting the seasonal reduction of the upstream Kuroshio transport(UKT) were investigated in the Regional Ocean Modeling System(ROMS). The vertically integrated energy scheme was utilized to identify sensitive areas based on two factors: the specific energy scheme and sensitive area size. Totally 27 sensitive areas, characterized by three energy schemes and nine sensitive area sizes, were evaluated. The results show that the total energy(TE) scheme was the most effective because it includes both the kinetic and potential components of CNOP. Generally, larger sensitive areas led to better predictions. The size of 0.5% of the model domain was chosen after balancing the effectiveness and efficiency of adaptive observation. The optimal sensitive area OSen was determined accordingly. Sensitivity experiments on OSen were then conducted, and the following results were obtained:(1) In OSen, initial errors with CNOP or CNOP-like patterns were more likely to yield worse predictions, and the CNOP pattern was the most unstable.(2) Initial errors in OSen rather than in other regions tended to cause larger prediction errors. Therefore, adaptive observation in OSen can be more beneficial for predicting the seasonal reduction of UKT.展开更多
Purpose： Exsanguination is the most common leading cause of death in trauma patients. The massive transfusion （MT） protocol may influence therapeutic strategies and help provide blood components in timely manner. T...Purpose： Exsanguination is the most common leading cause of death in trauma patients. The massive transfusion （MT） protocol may influence therapeutic strategies and help provide blood components in timely manner. The assessment of blood consumption （ABC） score is a popular MT protocol but has low predictability. The lactate level is a good parameter to reflect poor tissue perfusion or shock states that can guide the management. This study aimed to modify the ABC scoring system by adding the lactate level for better prediction of MTo Methods： The data were retrospectively collected from 165 trauma patients following the trauma acti- vated criteria at Songklanagarind Hospital from January 2014 to December 2014. The ABC scoring system was applied in all patients. The patients who had an ABC score 〉2 as the cut point for MT were defined as the ABC group. All patients who had a score 〉2 with a lactate level 〉4 mmol/dL were defined as the ABC plus lactate level （ABC ＋ L） group. The prediction for the requirement of massive blood transfusion was compared between the ABC and ABC ＋ L groups. The ability of ABC and ABC ＋ L groups to predict MT was estimated by the area under the receiver operating characteristic curve （AUROC）. Results： Among 165 patients, 15 patients （9%） required massive blood transfusion. There were no sig- nificant differences in age, gender, mechanism of injury or initial vital signs bet^teen the MT group and the non-MT group. The group that required MT had a higher Injury Severity Score and mortality. The sensitivity and specificity of the ABC scoring system in our institution were low （81%, 34%, AUC 0.573）. The sensitivity and specificity were significantly better in the ABC ＋ L group （92%, 42%, AUC = 0.745）. Conclusion： The ABC scoring system plus lactate increased the sensitivity and specificity compared with the ABC scoring system alone.展开更多
基金Supported by the National Natural Science Foundations of China （No. 40474001, No. 40274002, No. 40604003）.
文摘Three functional models, polynomial, spectral analysis, and modified AR model, are studied and compared in fitting and predicting clock deviation based on the data sequence derived from two-way satellite time and frequency transfer. A robust equivalent weight is applied, which controls the significant influence of outlying observations. Some conclusions show that the prediction precision of robust estimation is better than that of LS. The prediction precision calculated from smoothed observations is higher than that calculated from sampling observations. As a count of the obvious period variations in the clock deviation sequence, the predicted values of polynomial model are implausible. The prediction precision of spectral analysis model is very low, but the principal periods can be determined. The prediction RMS of 6-hour extrapolation interval is Ins or so, when modified AR model is used.
基金the support from the Meteoro-logical Science and Technology Research Project (2009-sdqz05),Shandong Meteorological Bureau
文摘To ensure the effectiveness of the operation of artificial precipitation enhancement, a potential region for the operation should be determined in advance.As cloud microphysical measurements needed for the determination of the potential region of cloud seeding are not available before the operation of routine precipitation enhancement, a new method based on the growth process of ice crystal is put forward for determining the potential region using the numerical weather prediction model output.The ice supersaturation, accumulated water vapor within minus temperature layer (≥9 mm), and upward water vapor transportation are adopted as criteria to determine the potential time, height and region of cloud seeding, and the real-time radar images are applied to make decisions on the seeding commanding.The criteria and Doppler radar images are studied in a case of precipitation enhancement characterized by significant water vapor supply from the north part of a tropical cyclone in the northwest Pacific, which shows that the ocean plays a crucial role in the advection transportation of water vapor to the potential region of the coastal area.The study presents a new method to determine the potential region of precipitation enhancement using macro-physical quantities under ice crystal growth environment.The method possesses a clear physical significance and can be readily applied with the required and easily predicted parameters.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDA11010303)the National Natural Science Foundation of China (Grant Nos. 41230420, 41306023 & 41421005)+1 种基金the National Natural Science Foundation of China-Shandong Joint Fund for Marine Science Research Centers (Grant No. U1406401)the support of K. C. Wong Foundation
文摘Using the conditional nonlinear optimal perturbation(CNOP) approach, sensitive areas of adaptive observation for predicting the seasonal reduction of the upstream Kuroshio transport(UKT) were investigated in the Regional Ocean Modeling System(ROMS). The vertically integrated energy scheme was utilized to identify sensitive areas based on two factors: the specific energy scheme and sensitive area size. Totally 27 sensitive areas, characterized by three energy schemes and nine sensitive area sizes, were evaluated. The results show that the total energy(TE) scheme was the most effective because it includes both the kinetic and potential components of CNOP. Generally, larger sensitive areas led to better predictions. The size of 0.5% of the model domain was chosen after balancing the effectiveness and efficiency of adaptive observation. The optimal sensitive area OSen was determined accordingly. Sensitivity experiments on OSen were then conducted, and the following results were obtained:(1) In OSen, initial errors with CNOP or CNOP-like patterns were more likely to yield worse predictions, and the CNOP pattern was the most unstable.(2) Initial errors in OSen rather than in other regions tended to cause larger prediction errors. Therefore, adaptive observation in OSen can be more beneficial for predicting the seasonal reduction of UKT.
文摘Purpose： Exsanguination is the most common leading cause of death in trauma patients. The massive transfusion （MT） protocol may influence therapeutic strategies and help provide blood components in timely manner. The assessment of blood consumption （ABC） score is a popular MT protocol but has low predictability. The lactate level is a good parameter to reflect poor tissue perfusion or shock states that can guide the management. This study aimed to modify the ABC scoring system by adding the lactate level for better prediction of MTo Methods： The data were retrospectively collected from 165 trauma patients following the trauma acti- vated criteria at Songklanagarind Hospital from January 2014 to December 2014. The ABC scoring system was applied in all patients. The patients who had an ABC score 〉2 as the cut point for MT were defined as the ABC group. All patients who had a score 〉2 with a lactate level 〉4 mmol/dL were defined as the ABC plus lactate level （ABC ＋ L） group. The prediction for the requirement of massive blood transfusion was compared between the ABC and ABC ＋ L groups. The ability of ABC and ABC ＋ L groups to predict MT was estimated by the area under the receiver operating characteristic curve （AUROC）. Results： Among 165 patients, 15 patients （9%） required massive blood transfusion. There were no sig- nificant differences in age, gender, mechanism of injury or initial vital signs bet^teen the MT group and the non-MT group. The group that required MT had a higher Injury Severity Score and mortality. The sensitivity and specificity of the ABC scoring system in our institution were low （81%, 34%, AUC 0.573）. The sensitivity and specificity were significantly better in the ABC ＋ L group （92%, 42%, AUC = 0.745）. Conclusion： The ABC scoring system plus lactate increased the sensitivity and specificity compared with the ABC scoring system alone.
