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Brightness temperature simulation of subarctic lake-ice evolution by HIGHTSI and SMRT model
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作者 ZHANG Yixiao QIU Yubao +3 位作者 PENG Chongtai Bin CHENG SHI Lijuan Matti LEPPARANTA 《Advances in Polar Science》 CSCD 2024年第3期303-323,共21页
Microwave brightness temperature(TB)can be used to retrieve lake ice thickness in the Arctic and subarctic regions.However,the accuracy of the retrieval is affected by the physical properties of lake ice.To improve th... Microwave brightness temperature(TB)can be used to retrieve lake ice thickness in the Arctic and subarctic regions.However,the accuracy of the retrieval is affected by the physical properties of lake ice.To improve the understanding of how lake ice affects TB,numerical modeling was applied.This study combined a physical thermodynamic ice model HIGHTSI with a microwave radiation transfer model SMRT to simulate the TB and lake ice evolution in 2002-2011 in Hulun Lake,China.The reanalyzed meteorological data were used as atmospheric forcing.The ice season was divided into the growth period,the slow growth period,and the ablation period.The simulations revealed that TB was highly sensitive to ice thickness during the ice season,especially vertical polarization measurement at 18.7 GHz.The quadratic polynomial fit for ice thickness to TB outperformed the linear fit,regardless of whether lake ice contained bubbles or not.A comparison of the simulated TB with space-borne TB showed that the simulated TB had the best accuracy during the slow growth period,with a minimum RMSE of 4.6 K.The results were influenced by the bubble radius and salinity.These findings enhance comprehension of the interaction between lake ice properties(including ice thickness,bubbles,and salinity)and TB during ice seasons,offering insights to sea ice in the Arctic and subarctic freshwater observations. 展开更多
关键词 lake ice evolution HIGHTSI SMRT ice thickness passive microwave brightness temperature
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Evaluating the Effects of Graviton Redshift upon Spiral Galaxy Rotation Curves, Surface Brightness Magnitudes and Gravitational Lensing
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作者 Firmin J. Oliveira 《Journal of High Energy Physics, Gravitation and Cosmology》 CAS 2024年第3期967-985,共19页
The effects of the gravitational redshift of gravitons upon spiral galaxy rotation energy are compared to the standard mass to light analyses in obtaining rotation curves. The derivation of the total baryonic matter c... The effects of the gravitational redshift of gravitons upon spiral galaxy rotation energy are compared to the standard mass to light analyses in obtaining rotation curves. The derivation of the total baryonic matter compares well with the standard theory and the rotation velocity is matched to a high precision. The stellar mass distributions obtained from the fit with graviton energy loss are used to derive the surface brightness magnitudes for the galaxies, which agree well with the observed measurements. In a new field of investigation, the graviton theory is applied to the observations of gravitational lenses. The results of these applications of the theory suggest that it can augment the standard methods and may eliminate the need for dark matter. 展开更多
关键词 GRAVITONS Gravitational Redshift Surface brightness Gravitational Lens Lens Mass
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Gamma Correction for Brightness Preservation in Natural Images
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作者 Navleen S Rekhi Jagroop S Sidhu Amit Arora 《Computer Systems Science & Engineering》 SCIE EI 2023年第3期2791-2807,共17页
Due to improper acquisition settings and other noise artifacts,the image degraded to yield poor mean preservation in brightness.The simplest way to improve the preservation is the implementation of histogram equalizat... Due to improper acquisition settings and other noise artifacts,the image degraded to yield poor mean preservation in brightness.The simplest way to improve the preservation is the implementation of histogram equalization.Because of over-enhancement,it failed to preserve the mean brightness and produce the poor quality of the image.This paper proposes a multi-scale decomposi-tion for brightness preservation using gamma correction.After transformation to hue,saturation and intensity(HSI)channel,the 2D-discrete wavelet transform decomposed the intensity component into low and high-pass coefficients.At the next phase,gamma correction is used by auto-tuning the scale value.The scale is the modified constant value used in the logarithmic function.Further,the scale value is optimized to obtain better visual quality in the image.The optimized value is the weighted distribution of standard deviation-mean of low pass coefficients.Finally,the experimental result is estimated in terms of quality assessment measures used as absolute mean brightness error,the measure of information detail,signal to noise ratio and patch-based contrast quality in the image.By comparison,the proposed method proved to be suitably remarkable in retaining the mean brightness and better visual quality of the image. 展开更多
关键词 Natural and aerial images wavelet transform gamma correction brightness preservation
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High Brightness,High Power Density Fiber Coupling of High Power Laser Diode
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作者 王晓薇 肖建伟 +5 位作者 王仲明 马骁宇 刘宗顺 方高瞻 张敬明 冯小明 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2001年第9期1112-1115,共4页
The output radiation from the 100μm×1μm aperture of a high power Laser Diode (LD) is efficiently coupled into a 50μm multimode optical fiber.The fiber output of the high power LD with high brightness and high ... The output radiation from the 100μm×1μm aperture of a high power Laser Diode (LD) is efficiently coupled into a 50μm multimode optical fiber.The fiber output of the high power LD with high brightness and high power density is achieved.The power density is up to 3 6×104W/cm2 and the coupling efficiency is 70%.The extreme divergence and the astigmatism of high power LDs require the optics with complex lens structures and high performance.A double-curved lens with two crossed cylindrical lenses structured on both sides of the glass substrate is used in the coupling system. 展开更多
关键词 high power LD double-curved lens fiber coupling high brightness high power density
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Cross-calibration between MWRI and AMSR2 to improve consistency of snow depth products
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作者 SiYu Wei LiYun Dai +1 位作者 LiJuan Ma Tao Che 《Research in Cold and Arid Regions》 CSCD 2024年第4期178-189,共12页
The Microwave Radiation Imager (MWRI), boarded on the FY-3 series satellites: FY-3B, FY-3C, and FY-3D, is thefirst satellite-based microwave radiometer in China, commencing passive microwave brightness temperature dat... The Microwave Radiation Imager (MWRI), boarded on the FY-3 series satellites: FY-3B, FY-3C, and FY-3D, is thefirst satellite-based microwave radiometer in China, commencing passive microwave brightness temperature dataacquisition since 2010. The Advanced Microwave Scanning Radiometer 2 (AMSR2) boarded on the Global ChangeObservation Mission 1st-Water (GCOM-W1), has been operational since 2012. Despite the FY-3 series satellitesare equipped with the same MWRI and all MWRIs sharing comparable parameters and configurations as AMSR2,disparities in observation times and satellite platforms result in inconsistencies in the data obtained by differentsatellites, which further impacting the consistency of retrieved geophysical parameters. To improve the consistency of brightness temperatures from FY-3B, FY-3C, FY-3D/MWRI, and GCOM-W1/AMSR2, cross-calibrationswere conducted among brightness temperatures at ten-channel from above four platforms. The consistency ofderived snow depth from MWRIs and AMSR2 in China before and after the calibration were also analyzed. Theresults show that the correlation coefficients of brightness temperatures at all channels between sensors exceed0.98. After cross-calibration, the RMSEs and biases of brightness temperatures at all frequencies and snow depthin China derived from them reduce to varying degrees. The consistencies in both brightness temperatures andsnow depth of FY-3B/MWRI, FY-3D/MWRI, and AMSR2 are higher than those of FY-3C and others. These findingsadvocate for the utilization of cross-calibrated brightness temperatures from FY-3B/MWRI, FY-3D/MWRI, andAMSR2, which share similar satellite overpass time, to derived a long-term snow depth dataset. 展开更多
关键词 Passive microwave brightness temperature FY-3 MWRI AMSR2 CROSS-CALIBRATION Snow depth
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Breast cancer imaging-clinical experience with two-dimensionalshear wave elastography:A retrospective study
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作者 Lyubomir Chervenkov Aleksandar Georgiev +1 位作者 Mladen Doykov Tsvetelina Velikova 《World Journal of Radiology》 2024年第10期528-536,共9页
BACKGROUND Breast cancer morbidity has been increasing worldwide,but treatments are improving.The therapeutic response depends on the stage at which the disease is diagnosed.Therefore,early diagnosis has never been mo... BACKGROUND Breast cancer morbidity has been increasing worldwide,but treatments are improving.The therapeutic response depends on the stage at which the disease is diagnosed.Therefore,early diagnosis has never been more essential for successful treatment and a reduction in mortality rates.Radiology plays a pivotal role in cancer detection,and advances in ultrasound(US)palpation have shown promising results for breast cancer imaging.The addition of two-dimensional-shear wave elastography(2D-SWE)US in the routine breast imaging exam can increase early cancer detection and promote better surveillance.AIM To evaluate the clinical applications of 2D-SWE US in breast cancer detection and its combination with other imaging modalities.METHODS The 200 consecutive female patients aged 50-80 were examined to evaluate palpable breast lesions.All patients underwent mammography,bright mode(B-mode)US,and 2D-SWE followed by US-guided biopsy in two consecutive sessions.RESULTS Combining B-mode and shear wave US imaging with X-ray mammography revealed 100%of the suspicious lesions,resulting in greater sensitivity,specificity,and negative predictive value.The result improves compared to either B-mode or 2D-SWE alone(P=0.02).CONCLUSION Combining 2D-SWE with conventional US and X-ray techniques improves the chance of early cancer detection.Including 2D-SWE in regular breast imaging routines can reduce the need for biopsies and improve the chance of early cancer detection and survivability with the proper line of therapy. 展开更多
关键词 Breast cancer Two-dimensional-shear wave elastography ULTRASOUND MAMMOGRAPHY Bright mode
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RS-based Analysis of the Correlation between Brightness Temperature and Vegetation Cover—A Case Study of Neijiang City,Sichuan Province of China
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作者 薛万蓉 许辉熙 +2 位作者 但尚铭 何政伟 仇文侠 《Journal of Landscape Research》 2012年第2期35-37,共3页
Landsat TM data(June 23,1988,May 6,2007) and Landsat ETM+data(May 10,2000) of Neijiang City,Sichuan Province was taken as the data source,brightness temperature of the study area was obtained by using TM/ETM+thermal i... Landsat TM data(June 23,1988,May 6,2007) and Landsat ETM+data(May 10,2000) of Neijiang City,Sichuan Province was taken as the data source,brightness temperature of the study area was obtained by using TM/ETM+thermal infrared wave,and also normalized difference vegetation index(NDVI) was calculated.NDVI of the study area on June 23,1988,May 6,2007,and May 10,2000 was respectively obtained by using Band Math,the least square fitting was adopted to simulate the correlation between surface temperature and vegetation cover.Moreover,linear regression analysis of the correlation between vegetation cover and NDVI was carried out in Excel.The results showed that(a) most of the constructed area has a low NDVI value because there are large areas of hard surface such as buildings and roads,but less vegetation cover;(b) the quarters with better vegetation cover have higher NDVI values;the Tuojiang River has a negative NDVI value;rural areas have better vegetation cover and higher NDVI values.Brightness temperature and vegetation cover has distinct negative correlation,specifically,the higher the vegetation cover is,the lower the surface temperature is,and vice versa. 展开更多
关键词 Urban heat ISLAND effects Remote sensing(RS) brightness temperature Normalized difference VEGETATION index(NDVI) CORRELATION ANALYSIS
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Comparative Analysis of Microwave Brightness Temperature Data in Northeast China Using AMSR-E and MWRI Products 被引量:7
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作者 GU Lingjia ZHAO Kai +1 位作者 ZHANG Shuwen ZHANG Shuang 《Chinese Geographical Science》 SCIE CSCD 2011年第1期84-93,共10页
With such significant advantages as all-day observation, penetrability and all-weather coverage, passive mi-crowave remote sensing technique has been widely applied in the research of global environmental change. As t... With such significant advantages as all-day observation, penetrability and all-weather coverage, passive mi-crowave remote sensing technique has been widely applied in the research of global environmental change. As the sat-ellite-based passive microwave remote sensor, the Advanced Microwave Scanning Radiometer-Earth Observing Sys-tem (AMSR-E) loaded on NASA's (National Aeronautics and Space Administration of USA) Aqua satellite has been popularly used in the field of microwave observation. The Microwave Radiation Imager (MWRI) loaded on the Chi-nese FengYun-3A (FY-3A) satellite is an AMSR-E-like conical scanning microwave sensor, but there are few reports about MWRI data. This paper firstly proposed an optimal spatial position matching algorithm from rough to exact for the position matching between AMSR-E and MWRI data, then taking Northeast China as an example, comparatively analyzed the microwave brightness temperature data derived from AMSR-E and MWRI. The results show that when the antenna footprints of the two sensors are filled with either full water, or full land, or mixed land and water with ap-proximate proportion, the errors of brightness temperature between AMSR-E and MWRI are usually in the range from -10 K to +10 K. In general, the residual values of brightness temperature between the two microwave sensors with the same spatial resolution are in the range of ±3 K. Because the spatial resolution of AMSR-E is three times as high as that of MWRI, the results indicate that the quality of MWRI data is better. The research can provide useful information for the MWRI data application and microwave unmixing method in the future. 展开更多
关键词 AMSR-E MWRI FY-3A satellite brightness temperature spatial resolution spatial position matching Northeast China
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Face anti-spoofing algorithm combined with CNN and brightness equalization 被引量:6
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作者 CAI Pei QUAN Hui-min 《Journal of Central South University》 SCIE EI CAS CSCD 2021年第1期194-204,共11页
Face anti-spoofing is a relatively important part of the face recognition system,which has great significance for financial payment and access control systems.Aiming at the problems of unstable face alignment,complex ... Face anti-spoofing is a relatively important part of the face recognition system,which has great significance for financial payment and access control systems.Aiming at the problems of unstable face alignment,complex lighting,and complex structure of face anti-spoofing detection network,a novel method is presented using a combination of convolutional neural network and brightness equalization.Firstly,multi-task convolutional neural network(MTCNN)based on the cascade of three convolutional neural networks(CNNs),P-net,R-net,and O-net are used to achieve accurate positioning of the face,and the detected face bounding box is cropped by a specified multiple,then brightness equalization is adopted to perform brightness compensation on different brightness areas of the face image.Finally,data features are extracted and classification is given by utilizing a 12-layer convolution neural network.Experiments of the proposed algorithm were carried out on CASIA-FASD.The results show that the classification accuracy is relatively high,and the half total error rate(HTER)reaches 1.02%. 展开更多
关键词 face anti-spoofing MTCNN brightness equalization convolutional neural network
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Color-stable,reduced efficiency roll-off hybrid white organic light emitting diodes with ultra high brightness 被引量:4
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作者 刘佰全 陶洪 +4 位作者 苏跃举 高栋雨 兰林锋 邹建华 彭俊彪 《Chinese Physics B》 SCIE EI CAS CSCD 2013年第7期450-453,共4页
High-brightness and color-stable two-wavelength hybrid white organic light emitting diodes (HWOLEDs) with the configuration of indium tin oxide (ITO)/ N, N, N, N-tetrakis(4-methoxyphenyl)-benzidine (MeO-TPD):... High-brightness and color-stable two-wavelength hybrid white organic light emitting diodes (HWOLEDs) with the configuration of indium tin oxide (ITO)/ N, N, N, N-tetrakis(4-methoxyphenyl)-benzidine (MeO-TPD): tetrafluoro-tetracyanoqino dimethane (F4-TCNQ)/N,N-di(naphthalene-1-yl)-N,N-diphenyl-benzidine (NPB)/ 4,4-N,N-dicarbazolebiphenyl (CBP): iridium (III) diazine complexes (MPPZ) 2 Ir(acac)/NPB/2-methyl-9,10-di(2-naphthyl)anthracene (MADN): p-bis(p-N,N-di-phenyl-aminostyryl)benzene (DSA-ph)/bis(10-hydroxybenzo[h] quino-linato)beryllium complex (Bebq2)/LiF/Al have been fabricated and characterized. The optimal brightness of the device is 69932 cd/m2 at a voltage of 13 V, and the Commission Internationale de l’Eclairage (CIE) chromaticity coordinates are almost constant during a large voltage change of 6–12 V. Furthermore, a current efficiency of 15.3 cd/A at an illumination-relevant brightness of 1000 cd/m2 is obtained, which rolls off slightly to 13.0 cd/A at an ultra high brightness of 50000 cd/m2. We attribute this great performance to wisely selecting an appropriate spacer together with effectively utilizing the combinations of exciton-harvested orange-phosphorescence/blue-fluorescence in the device. Undoubtedly, this is one of the most exciting results in two-wavelength HWOLEDs up to now. 展开更多
关键词 white light color stability efficiency roll-off high brightness
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Increase of brightness and transmission efficiency in fiat panel display through serial synchronous scanning mode with double buffers 被引量:4
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作者 陈章进 陈峰 +2 位作者 冉峰 徐美华 郑方 《Journal of Shanghai University(English Edition)》 CAS 2007年第3期314-317,共4页
This paper presents a serial synchronous scanning mode in fiat panel display (FPD) by adding a latch buffer between the serializer and the driving buffer. Comparing with conventional techniques, the proposed structu... This paper presents a serial synchronous scanning mode in fiat panel display (FPD) by adding a latch buffer between the serializer and the driving buffer. Comparing with conventional techniques, the proposed structure can efficiently reduce the brightness loss and improve the transmission performance. Theoretical analysis and experimental results show that the ratio between the lightest weight display time and the relative transmission time is a tradeoff between brightness loss and transmission efficiency. 展开更多
关键词 fiat panel display (FPD) serial scanning double buffer brightness loss transmission utilization
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MODIS BRIGHTNESS TEMPERATURE DATA ASSIMILATION UNDER CLOUDY CONDITIONS: METHODS AND IDEAL TESTS 被引量:5
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作者 丁伟钰 万齐林 +2 位作者 张诚忠 陈子通 黄燕燕 《Journal of Tropical Meteorology》 SCIE 2010年第4期313-324,共12页
Clouds have important effects on the infi'ared radiances transmission in that the inclusion of cloud effects in data assimilation can not only improve the quality of the assimilated atmospheric parameters greatly, bu... Clouds have important effects on the infi'ared radiances transmission in that the inclusion of cloud effects in data assimilation can not only improve the quality of the assimilated atmospheric parameters greatly, but also minimize the initial error of cloud parameters by adjusting part of the infrared radiances data. On the basis of the Grapes-3D-var (Global and Regional Assimilation and Prediction Enhanced System), cloud liquid water, cloud ice water and cloud cover are added as the governing variables in the assimilation. Under the conditions of clear sky, partly cloudy cover and totally cloudy cover, the brightness temperature of 16 MODIS channels are assimilated respectively in ideal tests. Results show that when the simulated background brightness temperatures are lower than the observation, the analyzed field will increase the simulated brightness temperature by increasing its temperature and reducing its moisture, cloud liquid water, cloud ice water, and cloud cover. The simulated brightness temperature can be reduced if adjustment is made in the contrary direction. The adjustment of the temperature and specific humidity under the clear sky conditions conforms well to the design of MODIS channels, but it is weakened for levels under cloud layers. The ideal tests demonstrate that by simultaneously adding both cloud parameters and atmospheric parameters as governing variables during the assimilation of infrared radiances, both the cloud parameters and atmospheric parameters can be adjusted using the observed infrared radiances and conventional meteorological elements to make full use of the infrared observations. 展开更多
关键词 cloud parameters MODIS brightness temperature data ASSIMILATION
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Cross-calibration of brightness temperature obtained by FY-3B/MWRI using Aqua/AMSR-E data for snow depth retrieval in the Arctic 被引量:3
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作者 Haihua Chen Lele Li Lei Guan 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2021年第1期43-53,共11页
This study cross-calibrated the brightness temperatures observed in the Arctic by using the FY-3B/MWRI L1 and the Aqua/AMSR-E L2A.The monthly parameters of the cross-calibration were determined and evaluated using rob... This study cross-calibrated the brightness temperatures observed in the Arctic by using the FY-3B/MWRI L1 and the Aqua/AMSR-E L2A.The monthly parameters of the cross-calibration were determined and evaluated using robust linear regression.The snow depth in case of seasonal ice was calculated by using parameters of the crosscalibration of data from the MWRI Tb.The correlation coefficients of the H/V polarization among all channels Tb of the two sensors were higher than 0.97.The parameters of the monthly cross-calibration were useful for the snow depth retrieval using the MWRI.Data from the MWRI Tb were cross-calibrated to the AMSR-E baseline.Biases in the data of the two sensors were optimized to approximately 0 K through the cross-calibration,the standard deviations decreased significantly in the range of 1.32 K to 2.57 K,and the correlation coefficients were as high as 99%.An analysis of the statistical distributions of the histograms before and after cross-calibration indicated that the FY-3B/MWRI Tb data had been well calibrated.Furthermore,the results of the cross-calibration were evaluated by data on the daily average Tb at 18.7 GHz,23.8 GHz,and 36.5 GHz(V polarization),and at 89 GHz(H/V polarization),and were applied to the snow depths retrieval in the Arctic.The parameters of monthly cross-calibration were found to be effective in terms of correcting the daily average Tb.The results of the snow depths were compared with those of the calibrated MWRI and AMSR-E products.Biases of 0.18 cm to 0.38 cm were observed in the monthly snow depths,with the standard deviations ranging from 4.19 cm to 4.80 cm. 展开更多
关键词 FY-3B AMSR-E brightness temperature(T^(b)) CROSS-CALIBRATION snow depth ARCTIC
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MODIS BRIGHTNESS TEMPERATURE DATA ASSIMILATION UNDER CLOUDY CONDITIONS Ⅱ: IMPACTS ON RAINSTORM FORECASTING 被引量:4
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作者 丁伟钰 万齐林 +2 位作者 黄燕燕 陈子通 张诚忠 《Journal of Tropical Meteorology》 SCIE 2011年第3期221-230,共10页
Satellite observations provide large amount of information of clouds and precipitation and play an important role in the forecast of heavy rainfall.However,we have not fully taken advantage of satellite observations i... Satellite observations provide large amount of information of clouds and precipitation and play an important role in the forecast of heavy rainfall.However,we have not fully taken advantage of satellite observations in the data assimilation of numerical weather predictions,especially those in infrared channels. It is common to only assimilate radiances under clear-sky conditions since it is extremely difficult to simulate infrared transmittance in cloudy sky.On the basis of the Global and Regional Assimilation and Prediction Enhanced System 3-dimensional variance(GRAPES-3DVar),cloud liquid water content, ice-water content and cloud cover are employed as governing variables in the assimilation system.This scheme can improve the simulation of infrared transmittance by a fast radiative transfer model for TOVS (RTTOV)and adjust the atmospheric and cloud parameters based on infrared radiance observations.In this paper,we investigate a heavy rainfall over Guangdong province on May 26,2007,which is right after the onset of a South China Sea monsoon.In this case,channels of the Moderate Resolution Imaging Spectroradiometer(MODIS)for observing water vapor(Channel 27)and cloud top altitude(Channel 36)are selected for the assimilation.The process of heavy rainfall is simulated by the Weather Research and Forecasting(WRF)model.Our results show that the assimilated MODIS data can improve the distribution of water vapor and temperature in the first guess field and indirectly adjust the upper-level wind field.The tendency of adjustment agrees well with the satellite observations.The assimilation scheme has positive impacts on the short-range forecasting of rainstorm. 展开更多
关键词 MODIS brightness temperature data ASSIMILATION RAINSTORM
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Verification and recalibration of HY-2A microwave radiometer brightness temperature 被引量:2
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作者 ZHAO Yili LI Huimin +1 位作者 CHEN Chuntao ZHU Jianhua 《Journal of Oceanology and Limnology》 SCIE CAS CSCD 2019年第3期968-981,共14页
HY-2A is the first one of the Chinese HY-2 ocean satellite series carrying a microwave radiometer(RM)to measure sea surface temperature,sea surface wind speed,atmospheric water vapor,cloud liquid water content,and rai... HY-2A is the first one of the Chinese HY-2 ocean satellite series carrying a microwave radiometer(RM)to measure sea surface temperature,sea surface wind speed,atmospheric water vapor,cloud liquid water content,and rain rate.We verified the RM level 1B brightness temperature(T B)to retrieve environmental parameters.In the verification,TB that simulated using the ocean-atmosphere radiative transfer model(RTM)was used as a reference.The total bias and total standard deviation(SD)of the RM level 1B TB,with reference to the RTM simulation,ranged-20.6-4.38 K and 0.7-2.93 K,respectively.We found that both the total bias and the total SD depend on the frequency and polarization,although the values for ascending and descending passes are different.In addition,substantial seasonal variation of the bias was found at all channels.The verification results indicate the RM has some problems regarding calibration,e.g.,correction of antenna spillover and antenna physical emission,especially for the 18.7-GHz channel.Based on error analyses,a statistical recalibration algorithm was designed and recalibration was performed for the RM level 1B TB.Validation of the recalibrated TB indicated that the quality of the recalibrated RM level 1B TB was improved significantly.The bias of the recalibrated T B at all channels was reduced to<0.4 K,seasonal variation was almost eradicated,and SD was diminished(i.e.,the SD of the 18.7-GHz channel was reduced by more than 0.5K). 展开更多
关键词 HY-2A MICROWAVE RADIOMETER brightness temperature(TB) VERIFICATION calibration
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Surface Brightness Temperature Variation of Different Land Use Types
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作者 石亦霏 查勇 《Agricultural Science & Technology》 CAS 2011年第12期1873-1876,1971,共5页
[Objective] The aim of this study is to investigate the surface brightness temperature variation of different land use types.[Method] Based on MODIS data in 2008 and IGBP land classification system,the surface brightn... [Objective] The aim of this study is to investigate the surface brightness temperature variation of different land use types.[Method] Based on MODIS data in 2008 and IGBP land classification system,the surface brightness temperature in the Yangtze River Delta area was calculated,and its rules and reasons were also discussed in this study.[Result] Different land use types had its own special brightness temperature variation.During the day,the brightness temperature was as follows:grassland or urban and built-up landcropland,forest land and barrenwetland and water.During the night,the brightness temperature was as follows:water,wetland and barrengrassland or urban and built-up landforest land and cropland.Brightness temperature showed the trend of high in summer and low in winter or increasing in spring and decreasing in fall.The characteristics of surface thermal radiation could be reflected better by brightness temperature at night.Solar radiation,mixed pixel,heat capacity,water content were the main reasons for the difference of brightness temperature in different land types.[Conclusion] The brightness temperature variation of different land use types has significance for water content analysis in soil and dynamic monitoring of land use. 展开更多
关键词 MODIS Remote sensing Surface brightness temperature Land use type
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Seasonal and Interannual Variations of Upper Tropospheric Water Vapor Band Brightness Temperature over the Global Monsoon Regions 被引量:2
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作者 钱维宏 朱亚芬 +1 位作者 谢安 叶谦 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 1998年第3期55-63,共9页
The upper-troposphere water vapor (UTWV) band brightness temperature (BT) dataset derived from the High-resolution Infrared Radiation Sounder (HIRS) channel 12 of the National Oceanic and Atmospheric Administration (N... The upper-troposphere water vapor (UTWV) band brightness temperature (BT) dataset derived from the High-resolution Infrared Radiation Sounder (HIRS) channel 12 of the National Oceanic and Atmospheric Administration (NOAA) polar satellites from 1979 to 1995 is used to analyze the seasonal and interannual variations for the global monsoon regions. Results show that (i) there are three major regions where the UTWV band BT varies significantly with season, i.e., South Asia, the western coastal South-North America tropical region and the low-latitude African region; (ii) UTWV band BT clearly reveals the water vapor temporal/spatial features as well as the atmospheric circulation structure over the low-latitude during the monsoon onset; and (iii) there is a remarkable relationship between the interannual variation of the UTWV band BT over the monsoon regions and the sea surface temperature anomaly in the eastern equatorial Pacific. 展开更多
关键词 MONSOON Seasonal variation Interannual variability Upper tropospheric water vapor brightness temperature
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Possible thermal brightness temperature anomalies associated with the Lushan(China) M_s7.0 earthquake on 20 April 2013 被引量:2
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作者 Tao Xie Weiyu Ma 《Earthquake Science》 CSCD 2015年第1期37-47,共11页
Lushan Ms7.0 earthquake occurred in Lushan county, Ya'an city, Sichuan province of China, on 20 April 2013, and caused 196 deaths, 23 people of missing and more than 12 thousand of people injured. In order to analyze... Lushan Ms7.0 earthquake occurred in Lushan county, Ya'an city, Sichuan province of China, on 20 April 2013, and caused 196 deaths, 23 people of missing and more than 12 thousand of people injured. In order to analyze the possible seismic brightness temperature anomalies which may be associated with Lushan earthquake, daily brightness temperature data for the period from 1 June 2011 to 31 May 2013 and the geographical extent of 25°E-35°N latitude and 98°E-108°E longitude are collected from Chinese geostationary meteorological satellite FY-2E. Continuous wavelet transform method which has good resolution both in time and frequency domains is used to analyze power spectrum of brightness temperature data. The results show that the rela- tive wavelet power spectrum (RWPS) anomalies appeared since 24 January 2013 and still lasted on 19 April. Anomalies firstly appeared at the middle part of Longmenshan fault zone and gradually spread toward the southwestern part of Longmenshan fault. Anomalies also appeared along the Xianshuihe fault since about 1 March. Eventually, anomalies gathered at the intersection zone of Longmenshan and Xianshuihe faults. The anomalous areas and RWPS ampli- tude increased since the appearance of anomalies and reached maximum in late March. Anomalies attenuated with the earthquake approaching. And eventually the earthquake occurred at the southeastern edge of anomalous areas. Lushah earthquake was the only obvious geological event within the anomalous area during the time period, so the anomalous changes of RWPS are possibly associated with the earthquake. 展开更多
关键词 Lushan earthquake brightness temperatureThermal anomaly Wavelet transform Sichuan province
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The brightness reversal of submarine sand waves in “HJ-1A/B” CCD sun glitter images 被引量:2
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作者 HE Xiekai CHEN Ninghua +1 位作者 ZHANG Huaguo GUAN Weibing 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2015年第1期94-99,共6页
The brightness reversal of submarine sand waves appearing in the small satellite constellation for environ- ment and disaster monitoring and forecasting ("HJ- 1A/B") CCD sun glitter images can affect the observati... The brightness reversal of submarine sand waves appearing in the small satellite constellation for environ- ment and disaster monitoring and forecasting ("HJ- 1A/B") CCD sun glitter images can affect the observation and depth inversion of sand wave topography. The simulations of the normalized sun glitter radiance on the submarine sand waves confirm that the reversal would happen at a specific sensor viewing angle, defined as the critical angle. The difference between the calculated critical angle position and the reversal position in the image is about 1', which is excellent in agreement. Both the simulation and actual image show that sand wave crests would be indistinct at the reversal position, which may cause problems when using these sun glitter images to analyze spatial characteristics and migration of sand waves. When using the sun glitter image to obtain the depth inversion, one should take the advantage of image properties of sand waves and choose the location in between the reversal position and the brightest position. It is also necessary to pay attention to the brightness reversal when using "HI-1A/B" CCD images to analyze other oceanic features, such as internal waves, oil slicks, eddies, and ship wakes. 展开更多
关键词 "HJ-1A/B" CCD sun glitter image submarine sand waves brightness reversal Taiwan Banks
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Genome-wide association studies reveal QTL hotspots for grain brightness and black point traits in barley 被引量:1
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作者 Yong Jia Sharon Westcott +7 位作者 Tianhua He Lee Anne McFawn Tefera Angessa Camila Hill Cong Tan Xiaoqi Zhang Gaofeng Zhou Chengdao Li 《The Crop Journal》 SCIE CSCD 2021年第1期154-167,共14页
Grain kernel discoloration(KD)in cereal crops leads to down-grading grain quality and substantial economic losses worldwide.Breeding KD tolerant varieties requires a clear understanding of the genetic basis underlying... Grain kernel discoloration(KD)in cereal crops leads to down-grading grain quality and substantial economic losses worldwide.Breeding KD tolerant varieties requires a clear understanding of the genetic basis underlying this trait.Here,we generated a high-density single nucleotide polymorphisms(SNPs)map for a diverse barley germplasm and collected trait data from two independent field trials for five KD related traits:grain brightness(TL),redness(Ta),yellowness(Tb),black point impact(Tbpi),and total black point in percentage(Tbpt).Although grain brightness and black point is genetically correlated,the grain brightness traits(TL,Ta,and Tb)have significantly higher heritability than that of the black point traits(Tbpt and Tbpi),suggesting black point traits may be more susceptible to environmental influence.Using genome-wide association studies(GWAS),we identified a total of 37 quantitative trait loci(QTL),including two major QTL hotspots on chromosomes 4H and 7H,respectively.The two QTL hotspots are associated with all five KD traits.Further genetic linkage and gene transcription analyses identified candidate genes for the grain KD,including several genes in the flavonoid pathway and plant peroxidase.Our study provides valuable insights into the genetic basis for the grain KD in barley and would greatly facilitate future breeding programs for improving grain KD resistance. 展开更多
关键词 BARLEY Black point Grain brightness GWAS Kernel discoloration SNP markers
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