Based on the observations of a squall line on 11 May 2020 and stratiform precipitation on 6 June 2020 from two X-band dual-polarization phased array weather radars(DP-PAWRs)and an S-band dual-polarization Doppler weat...Based on the observations of a squall line on 11 May 2020 and stratiform precipitation on 6 June 2020 from two X-band dual-polarization phased array weather radars(DP-PAWRs)and an S-band dual-polarization Doppler weather radar(CINRAD/SA-D),the data reliability of DP-PAWR and its ability to detect the fine structures of mesoscale weather systems were assessed.After location matching,the observations of DP-PAWR and CINRAD/SA-D were compared in terms of reflectivity(Z_(H)),radial velocity(V),differential reflectivity(Z_(DR)),and specific differential phase(K_(DP)).The results showed that:(1)DP-PAWR has better ability to detect mesoscale weather systems than CINRAD/SAD;the multi-elevation-angles scanning of the RHI mode enables DP-PAWR to obtain a wider detection range in the vertical direction.(2)DP-PAWR’s Z_(H)and V structures are acceptable,while its sensitivity is worse than that of CINRAD/SA-D.The Z H suffers from attenuation and the Z_(H)area distribution is distorted around strong rainfall regions.(3)DP-PAWR’s Z_(DR)is close to a normal distribution but slightly smaller than that of CINRAD/SA-D.The K_(DP)products of DP-PAWR have much higher sensitivity,showing a better indication of precipitation.(4)DP-PAWR is capable of revealing a detailed and complete structure of the evolution of the whole storm and the characteristics of particle phase variations during the process of triggering and enhancement of a small cell in the front of a squall line,as well as the merging of the cell with the squall line,which cannot be observed by CINRAD/SA-D.With its fast volume scan feature and dual-polarization detection capability,DP-PAWR shows great potential in further understanding the development and evolution mechanisms of meso-γ-scale and microscale weather systems.展开更多
The title compound 6?-chloro-4?-methylene-3 H-spiro [isoben zofura-1,3?-isochroman], C_(17)H_(13)ClO_2, was prepared and characterized by IR, NMR, HRMS and single-crystal X-ray diffraction. This compound has a bisbenz...The title compound 6?-chloro-4?-methylene-3 H-spiro [isoben zofura-1,3?-isochroman], C_(17)H_(13)ClO_2, was prepared and characterized by IR, NMR, HRMS and single-crystal X-ray diffraction. This compound has a bisbenzannulated [5,5]-spiroketals skeleton. It crystallizes in orthorhombic, space group P212121 with a = 13.383(3), b = 7.6120(17), c = 13.793(3) ?, Z = 4, Dc= 1.275 g/cm^3, μ = 0.28 mm^(–1), F(000) = 592, wR = 0.1443 and R = 0.0557. The preliminary biological test showed that the title compound has good anti-bacterial activities in vitro.展开更多
基金Guangdong Basic and Applied Basic Research Foundation(2020A1515010602)Special Fund of China Meteorological Administration for Innovation and Development(CXFZ2022J063)+4 种基金Special Fund for Forecasters of China Meteorological Administration(CMAYBY2019-082)Science and Technology Planning Program of Guangzhou(201903010101)Key-Area Research and Development Program of Guangdong Province(2020B1111200001)National Natural Science Foundation of China(42075190,41875182)Radar Application and Shortterm Severe-weather Predictions and Warnings Technology Program(GRMCTD202002)。
文摘Based on the observations of a squall line on 11 May 2020 and stratiform precipitation on 6 June 2020 from two X-band dual-polarization phased array weather radars(DP-PAWRs)and an S-band dual-polarization Doppler weather radar(CINRAD/SA-D),the data reliability of DP-PAWR and its ability to detect the fine structures of mesoscale weather systems were assessed.After location matching,the observations of DP-PAWR and CINRAD/SA-D were compared in terms of reflectivity(Z_(H)),radial velocity(V),differential reflectivity(Z_(DR)),and specific differential phase(K_(DP)).The results showed that:(1)DP-PAWR has better ability to detect mesoscale weather systems than CINRAD/SAD;the multi-elevation-angles scanning of the RHI mode enables DP-PAWR to obtain a wider detection range in the vertical direction.(2)DP-PAWR’s Z_(H)and V structures are acceptable,while its sensitivity is worse than that of CINRAD/SA-D.The Z H suffers from attenuation and the Z_(H)area distribution is distorted around strong rainfall regions.(3)DP-PAWR’s Z_(DR)is close to a normal distribution but slightly smaller than that of CINRAD/SA-D.The K_(DP)products of DP-PAWR have much higher sensitivity,showing a better indication of precipitation.(4)DP-PAWR is capable of revealing a detailed and complete structure of the evolution of the whole storm and the characteristics of particle phase variations during the process of triggering and enhancement of a small cell in the front of a squall line,as well as the merging of the cell with the squall line,which cannot be observed by CINRAD/SA-D.With its fast volume scan feature and dual-polarization detection capability,DP-PAWR shows great potential in further understanding the development and evolution mechanisms of meso-γ-scale and microscale weather systems.
基金National Key Technology Support Program(No.2015BAD11B02)Agricultural Science and Technology Innovation Program(ASTIP,No.CAASASTIP-2014-LIHPS-04)
文摘The title compound 6?-chloro-4?-methylene-3 H-spiro [isoben zofura-1,3?-isochroman], C_(17)H_(13)ClO_2, was prepared and characterized by IR, NMR, HRMS and single-crystal X-ray diffraction. This compound has a bisbenzannulated [5,5]-spiroketals skeleton. It crystallizes in orthorhombic, space group P212121 with a = 13.383(3), b = 7.6120(17), c = 13.793(3) ?, Z = 4, Dc= 1.275 g/cm^3, μ = 0.28 mm^(–1), F(000) = 592, wR = 0.1443 and R = 0.0557. The preliminary biological test showed that the title compound has good anti-bacterial activities in vitro.
