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Estimating the Correlated Observation-Error Characteristics of the Chinese FengYun Microwave Temperature Sounder and Microwave Humidity Sounder

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Advances in Atmospheric Sciences 2018年第11期35卷 1428-1441页

作者： Ting WANG Jianfang FEI Xiaoping CHENG Xiaogang HUANG Jian ZHONG College of Meteorology and Oceanography National University of Defense TechnologyNanjing 211101China China Satellite Maritime Tracking and Control Department Jiangyin 214431China

In operational data assimilation systems, observation-error covariance matrices are commonly assumed to be ***, inter-channel and spatial observation-error correlations are inevitable for satellite radiances. The observation errors of the Microwave Temperature Sounder(MWTS) and Microwave Humidity Sounder(MWHS) onboard the FengYun-3A(FY-3A) and FY-3B satellites are empirically assigned and considered to be uncorrelated when they are assimilated into the WRF model's Community Variational Data Assimilation System(WRFDA). To assimilate MWTS and MWHS measurements optimally, a good characterization of their observation errors is necessary. In this study, background and analysis residuals were used to diagnose the correlated observation-error characteristics of the MWTS and MWHS. It was found that the error standard deviations of the MWTS and MWHS were less than the values used in the WRFDA. MWTS had small inter-channel errors, while MWHS had significant inter-channel errors. The horizontal correlation length scales of MWTS and MWHS were about 120 and 60 km, respectively. A comparison between the diagnosis for instruments onboard the two satellites showed that the observation-error characteristics of the MWTS or MWHS were different when they were onboard different satellites. In addition, it was found that the error statistics were dependent on latitude and scan *** forecast experiments showed that using a modified thinning scheme based on diagnosed statistics can improve forecast accuracy.

关键词： data assimilation correlated observation errors MWTS(Microwave Temperature Sounder) MWHS(Microwave Humidity Sounder)

WAVELET ANALYSIS OF MULTIFRACTAL AND ITS APPLICATION TO PROCESSING TEMPERATURE DATA IN RAYLEIGH-BENARD CONVECTION

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Journal of Hydrodynamics 2001年第4期13卷 34-41页

作者： Fu, Qiang Xia, Ke-Qing Div. of Appl. Mech. Inst. of Sci. Univ. of Sci. and Technol. of PLA Nanjing 211101 China

Wavelet transform was firstly used to analyze te singularity of a given signal, and then with the method of wavelet transform modulus maximum(WTMM), the characters of fractal set of triadic Cantor was studied. The results show that one can, not only determine the position of singular of signal, but also estimate the Holder exponent h which describes the strength of singularity and other parameters, such as D(h) and τ(q) correctly. Finally, after applying this method to process temperature data in the Rayleigh-Benard convection further, we found that the multifractal hierarchical and multi-scale structure underlying this flow could be entirely revealed from the parameters h, D(h) and τ(q), and the obtained results agree well with the ones determined from the viewpoint of fractal measures.

关键词： Heat convection Wavelet transforms

Congestion　Control　for　ATM　Networks　Based　on　Diagonal　Recurent　Neural　Networks

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通信学报 1997年第3期18卷 92-97页

作者： Huang Yunxian Yan Wei (Air Force Institute of Meteorology,Nanjing 211101) Air Force Institute of Meteorology 江苏南京 211101 Air Force Institute of Meteorology 江苏南京

ＣｏｎｇｅｓｔｉｏｎＣｏｎｔｒｏｌｆｏｒＡＴＭＮｅｔｗｏｒｋｓＢａｓｅｄｏｎＤｉａｇｏｎａｌＲｅｃｕｒｅｎｔＮｅｕｒａｌＮｅｔｗｏｒｋｓＨｕａｎｇＹｕｎｘｉａｎＹａｎＷｅｉ（ＡｉｒＦｏｒｃｅＩｎｓｔｉｔｕｔｅｏｆＭｅ... 详细信息

ＣｏｎｇｅｓｔｉｏｎＣｏｎｔｒｏｌｆｏｒＡＴＭＮｅｔｗｏｒｋｓＢａｓｅｄｏｎＤｉａｇｏｎａｌＲｅｃｕｒｅｎｔＮｅｕｒａｌＮｅｔｗｏｒｋｓＨｕａｎｇＹｕｎｘｉａｎＹａｎＷｅｉ（ＡｉｒＦｏｒｃｅＩｎｓｔｉｔｕｔｅｏｆＭｅｔｅｏｒｏｌｏｇｙ，Ｎａｎｊｉｎｇ...

关键词： diagonal recurrent neural networks congestion control ATM networks

基流对热对流涡旋结构影响的实验结果初步分析

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物理学报 2002年第9期51卷 2057-2062页

作者：林上金解放军理工大学南京211101

用实验室模拟方法研究了径向温度梯度对热对流涡旋的影响 ,结果表明 ,径向温度梯度所引起的基流使热对流涡旋的对称性结构被破坏 ,使涡旋变成非对称结构 ,并使涡旋向基流下游偏移 ,其强度随基流的加强而减弱 ,直至消失 .热对流涡旋越强... 详细信息

用实验室模拟方法研究了径向温度梯度对热对流涡旋的影响 ,结果表明 ,径向温度梯度所引起的基流使热对流涡旋的对称性结构被破坏 ,使涡旋变成非对称结构 ,并使涡旋向基流下游偏移 ,其强度随基流的加强而减弱 ,直至消失 .热对流涡旋越强其对称性结构越稳定。

关键词：转盘实验基流热对流涡旋径向温度梯度对称性结构天然系统

Retrieval of Sea Surface Wind Speed by One-Dimensional Synthetic Aperture Microwave Radiometer

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Journal of Tropical Meteorology 2021年第1期27卷 62-69页

作者： AI Wei-hua FENG Meng-yan LU Wen MA Shuo CHEN Guan-yu College of Meteorology and Oceanography National University of Defense TechnologyNanjing 211101 China PLA Troop 32033 Haikou 570100 China

One-dimensional synthetic aperture microwave radiometers have higher spatial resolution and record measurements at multiple incidence *** this paper,we propose a multiple linear regression method to retrieve sea surface wind speed at an incidence angle between 0°65°.We assume that a one-dimensional synthetic aperture microwave radiometer operates at frequencies of 6.9,10.65,18.7,23.8 and 36.5 ***,the microwave radiative transfer forward model is used to simulate the measured brightness *** sensitivity of the brightness temperatures at 0°65°to the sea surface wind speed is ***,vertical polarization channels(VR),horizontal polarization channels(HR)and all channels(AR)are used to retrieve the sea surface wind speed via a multiple linear regression algorithm at 0°65°,and the relationship between the retrieval error and incidence angle is *** results are as follows:(1)The sensitivity of the vertical polarization brightness temperature to the sea surface wind speed is smaller than that of the horizontal polarization.(2)The retrieval error increases with Gaussian *** retrieval error of VR first increases and then decreases with increasing incidence angle,the retrieval error of HR gradually decreases with increasing incidence angle,and the retrieval error of AR first decreases and then increases with increasing incidence angle.(3)The retrieval error of AR is the lowest and it is necessary to retrieve the sea surface wind speed at a larger incidence angle for AR.

关键词： sea surface wind speed high spatial resolution synthetic aperture microwave radiometer multiple incidence angles multiple linear regression algorithm

ENSO frequency change in coupled climate models as response to the increasing CO_2 concentration

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Chinese Science Bulletin 2010年第8期55卷 744-751页

作者： DENG Lin YANG XiuQun XIE Qian School of Atmospheric Sciences Nanjing University Nanjing 210093 China Institute of Meteorology PLA University of Science and Technology Nanjing 211101 China

The response of ENSO frequency to the increasing CO2 concentration and associated mechanism are examined with outputs of four coupled climate models (GFDL/CM2.0,CNRM/CM3,IPSL/CM4 and INM/CM3.0) submitted to the IPCC Fourth Assessment Report (IPCC AR4).Results reveal a significant change of ENSO frequency as response to the increasing CO2 ***,such a change exhibits an evident model *** ENSO frequency tends to increase in GFDL/CM2.0 and CNRM/CM3 models and decreases in IPSL/CM4 and INM/CM3.0 *** model dependence is found to be determined by how the model climatological background state of the tropical Pacific responds to the increasing CO 2 *** is demonstrated that the change of zonally-and vertically-averaged climatological background upper ocean temperature gradient between the equator and off-equator is crucially responsible for the ENSO frequency *** response to the increasing CO 2 concentration,the climatological background temperature gradient is increased in GFDL/CM2.0 and CNRM/CM3 models and decreased in IPSL/CM4 and INM/CM3.0 *** terms of the recharge-discharge oscillator theory for ENSO,the increased (decreased) climatological background temperature gradient between the equator and off-equator induces a faster (slower) exchange of oceanic heat content between the equator and off-equator,thus giving rise to a shorter (longer) ENSO timescale and a higher (lower) ENSO frequency.

关键词：二氧化碳浓度 ENSO 频率响应气候模式耦合气候背景温度梯度评估报告

Precipitation Microphysical Processes in the Inner Rainband of Tropical Cyclone Kajiki (2019) over the South China Sea Revealed by Polarimetric Radar

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Advances in Atmospheric Sciences 2021年第1期38卷 65-80页

作者： Hepeng ZHENG Yun ZHANG Lifeng ZHANG Hengchi LEI Zuhang WU College of Meteorology and Oceanography National University of Defense TechnologyNanjing 211101China Institute of Atmospheric Physics Chinese Academy of SciencesBeijing 100029China

Polarimetric radar and 2D video disdrometer observations provide new insights into the precipitation microphysical processes and characteristics in the inner rainband of tropical cyclone(TC)Kajiki(2019)in the South China Sea for the first *** precipitation of Kajiki is dominated by high concentrations and small(<3 mm)raindrops,which contribute more than 98%to the total *** average mass-weighted mean diameter and logarithmic normalized intercept are 1.49 mm and 4.47,respectively,indicating a larger mean diameter and a lower concentration compared to the TCs making landfall in eastern *** ice processes of the inner rainband are dramatically different among different *** riming process is dominant during the mature stage,while during the decay stage the aggregation process is *** vertical profiles of the polarimetric radar variables together with ice and liquid water contents in the convective region indicate that the formation of precipitation is dominated by warm-rain *** raindrops collect cloud droplets and other raindrops,causing reflectivity,differential reflectivity,and specific differential phase to increase with decreasing *** is,accretion and coalescence play a critical role in the formation of heavy *** melting of different particles generated by the ice process has a great influence on the initial raindrop size distribution(DSD)to further affect the warm-rain *** DSD above heavy rain with the effect of graupel has a wider spectral width than the region without the effect of graupel.

关键词： South China Sea cloud precipitation microphysics polarimetric radar tropical cyclone rainband

WindSat satellite comparisons with nearshore buoy wind data near the U.S. west and east coasts

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Acta Oceanologica Sinica 2016年第7期35卷 50-58页

作者： ZHANG Lei SHI Hanqing YU Hong YI Xin Institute of Meteorology and Oceanography People's Liberation Army University of Science and Technology Nanjing 211101 China Beijing Institute of Applied Meteorology Beijing 100029 China

Nearshore wind speeds retrieved by WindSat are validated by a comparison with the moored buoy observations near the U.S. west and east coasts. A 30 min and 25 km collection window is used for the WindSat wind data and buoy measurements from ]anuary 2004 to December 2014. Comparisons show that the overall root-mean-square error is better than 1.44 m/s near the U.S. coasts, and the result for the east coast is better than that for the west coast. The retrieval accuracy of the descending portions is slightly better than that of the ascending portions. Most buoy-to-buoy variations are not significantly correlated with the coastal topography, the longitude and the distance from the shore or satellite-buoy separation distance. In addition, comparisons between a polarimetric microwave radiometer and a microwave scatterometer are accomplished with the nearshore buoy observations from 2007 to 2008. The WindSat-derived winds tend to be lower than the buoy observations near the U.S. coasts. In contrast, the QuikSCAT-derived winds tend to be higher than the buoy observations. Overall, the retrieval accuracy of WindSat is slightly better than that of QuikSCAT, and these satellite-derived winds are sufficiently accurate for scientific studies.

关键词： WindSat polarimetric microwave radiometer nearshore wind validation

Parameterization of the sea spray generation function with whitecap coverage

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Acta Oceanologica Sinica 2020年第8期39卷 24-33页

作者： Jian Shi Wenjing Zhang Xueyan Zhang Jingdong Liu Zhenyu Liu College of Meteorology and Oceanography National University of Defense TechnologyNanjing 211101China Unit 91604 of the Chinese People’s Liberation Army Longkou 265700China

Sea spray droplets are produced by waves breaking on the sea surface, and they vary the transfer of energy between the atmosphere and ocean. The sea spray generation function(SSGF) is generally considered as a function of the initial radius of the spray droplets and the wind speed. However, ocean waves always exist at the air-sea interface, so it is not reasonable to consider only the effect of sea surface winds while ignoring the effects of ocean waves. Whitecap coverage is an important characteristic parameter of breaking waves, and researchers believe that this parameter is related to both wave state and wind speed. In this paper, the SSGF is parameterized by the whitecap coverage, and a new SSGF describing different droplet radii is organically integrated based on the whitecap coverage parameter. Then, with the relationship between the whitecap coverage and wave state, the influence of ocean waves on the SSGF for different wave states was analyzed by using observational data in the laboratory. The results show that the new SSGF that considers wave effects can reasonably describe the droplet generation process under different wave state conditions.

关键词： sea spray generation function whitecap coverage wave state