Many observational studies have shown that deformation, like vertical vorticity and divergence, is closely related to the occurrence and distribution of strong precipitation. In this paper, to involve deformation in p...Many observational studies have shown that deformation, like vertical vorticity and divergence, is closely related to the occurrence and distribution of strong precipitation. In this paper, to involve deformation in precipitation diagnosis, a new parameter called potential deformation（PD） is derived and then applied to precipitation detection within a simulated mesoscale convective system（MCS）. It is shown that PD includes both stretching deformation and shearing deformation and shares similar characteristics with deformation insofar as it does not change with the rotating coordinate. Diagnosis of the simulated MCS reveals that PD performs well in tracing the MCS＇ precipitation. In terms of their distributional pattern, the large-value areas of PD are similar to the precipitation in the different development stages of the MCS. A detailed analysis of the physical processes contained within the PD shows that it can reflect the three-dimensional moisture variation,vertical wind shear and wind deformation within the MCS. These structures are usually a comprehensive reflection of the characteristics of the surface cold pool, rear inflow jet, downward cold air flow and upward warm moist flow within the precipitating convective cells. For this reason, the PD shows much stronger anomalies in the precipitating atmosphere than the non-precipitating atmosphere, which implies considerable potential for its application in detecting heavy precipitation within MCSs.展开更多
Saffron is the most precious and expensive agricultural product. A dehydration treatment is necessary to convert Crocus sativus L. stigmas into saffron spice. To the best of our knowledge, no information on mass trans...Saffron is the most precious and expensive agricultural product. A dehydration treatment is necessary to convert Crocus sativus L. stigmas into saffron spice. To the best of our knowledge, no information on mass transfer parameters of saffron stigmas is available in the literature. This study aimed at investigating the moisture transfer parameters and quality attributes of saffron stigmas under infrared treatment at different temperatures（60,70, …, 110 ℃）. It was observed that the dehydration process of the samples occurred in a short accelerating rate period at the start followed by a falling rate period. The effective moisture diffusivity and convective mass transfer coefficient were determined by using the Dincer and Dost model. The diffusivity values varied from1.1103 × 10^-10m^2·s^-1to 4.1397 × 10^-10m^2·s^-1 and mass transfer coefficient varied in the range of 2.6433 × 10^-7–8.7203 × 10^-7m·s^-1. The activation energy was obtained to be 27.86 kJ·mol^-1. The quality assessment results showed that the total crocin content increased, when the temperature increased up to90 ℃ but, in higher temperatures, the amount of crocin decreased slightly. The total safranal content of the samples decreased slightly when drying temperature increased from 60 ℃ to 70 ℃ and then continuously increased up to 110 ℃. Also, the amount of picrocrocin increased from 83.1 to 93.3 as the drying temperature increased from 60 ℃ to 100 ℃.展开更多
基金supported by the Special Scientific Research Fund of the Meteorological Public Welfare of the Ministry of Sciences and Technology (Grant No. GYHY201406002, GYHY201406001)National Key Technology Support Program (Grant No. 2015BAC03B04)+4 种基金a National Program on Key Basic Research project (Grant No. 2013CB430105)the Major Research Plan of the National Natural Science Foundation of China (Grant No. 91437215)the National Natural Science Foundation of China (Grant Nos. 41505040, 41375052 41405055 and 41575065)the Open Project of the State Key Laboratory of Severe Weather (La SW), the Chinese Academy of Meteorological Sciences (CAMS) (Grant No. 2015LASW-B05)the Beijing Natural Sciences Foundation (Grant No. 8142035)
文摘Many observational studies have shown that deformation, like vertical vorticity and divergence, is closely related to the occurrence and distribution of strong precipitation. In this paper, to involve deformation in precipitation diagnosis, a new parameter called potential deformation（PD） is derived and then applied to precipitation detection within a simulated mesoscale convective system（MCS）. It is shown that PD includes both stretching deformation and shearing deformation and shares similar characteristics with deformation insofar as it does not change with the rotating coordinate. Diagnosis of the simulated MCS reveals that PD performs well in tracing the MCS＇ precipitation. In terms of their distributional pattern, the large-value areas of PD are similar to the precipitation in the different development stages of the MCS. A detailed analysis of the physical processes contained within the PD shows that it can reflect the three-dimensional moisture variation,vertical wind shear and wind deformation within the MCS. These structures are usually a comprehensive reflection of the characteristics of the surface cold pool, rear inflow jet, downward cold air flow and upward warm moist flow within the precipitating convective cells. For this reason, the PD shows much stronger anomalies in the precipitating atmosphere than the non-precipitating atmosphere, which implies considerable potential for its application in detecting heavy precipitation within MCSs.
文摘Saffron is the most precious and expensive agricultural product. A dehydration treatment is necessary to convert Crocus sativus L. stigmas into saffron spice. To the best of our knowledge, no information on mass transfer parameters of saffron stigmas is available in the literature. This study aimed at investigating the moisture transfer parameters and quality attributes of saffron stigmas under infrared treatment at different temperatures（60,70, …, 110 ℃）. It was observed that the dehydration process of the samples occurred in a short accelerating rate period at the start followed by a falling rate period. The effective moisture diffusivity and convective mass transfer coefficient were determined by using the Dincer and Dost model. The diffusivity values varied from1.1103 × 10^-10m^2·s^-1to 4.1397 × 10^-10m^2·s^-1 and mass transfer coefficient varied in the range of 2.6433 × 10^-7–8.7203 × 10^-7m·s^-1. The activation energy was obtained to be 27.86 kJ·mol^-1. The quality assessment results showed that the total crocin content increased, when the temperature increased up to90 ℃ but, in higher temperatures, the amount of crocin decreased slightly. The total safranal content of the samples decreased slightly when drying temperature increased from 60 ℃ to 70 ℃ and then continuously increased up to 110 ℃. Also, the amount of picrocrocin increased from 83.1 to 93.3 as the drying temperature increased from 60 ℃ to 100 ℃.
