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A performance evaluation of remotely sensed sea surface salinity products in combination with other surface measurements in reconstructing three-dimensional salinity fields

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Acta Oceanologica Sinica 2017年第7期36卷 15-31页

作者： CHEN Jian YOU Xiaobao XIAO Yiguo ZHANG Ren WANG Gongjie BAO Senliang Beijing institute of Applied meteorology Beijing 100029China institute of meteorology and Oceanography PLA University of Science and TechnologyNanjing 211101China

Several remotely sensed sea surface salinity（SSS） retrievals with various resolutions from the soil moisture and ocean salinity（SMOS） and Aquarius/SAC-D missions are applied as inputs for retrieving salinity profiles（S） using multilinear regressions. The performance is evaluated using a total root mean square（RMS） error, different error sources, and the feature resolutions of the retrieved S fields. In the mixed layer of the salinity, the SSS-S regression coefficients are uniformly large. The SSS inputs yield smaller RMS errors in the retrieved S with respect to Argo profiles as their spatial or temporal resolution decreases. The projected SSS errors are dominant, and the retrieved S values are more accurate than those of climatology in the tropics except for the tropical Atlantic, where the regression errors are abnormally large. Below that level, because of the influence of a sea level anomaly, the areas of high-accuracy S values shift to higher latitudes except in the high-latitude southern oceans, where the projected SSS errors are abnormally large. A spectral analysis suggests that the CATDS-0.25° results are much noisier and that the BEC-L4-0.25° results are much smoother than those of the other retrievals. Aquarius-CAP-1° generates the smallest RMS errors, and Aquarius-V2-1° performs well in depicting large-scale phenomena. BEC-L3-0.25°,which has small RMS errors and remarkable mesoscale energy, is the best fit for portraying mesoscale features in the SSS and retrieved S fields. The current priority for retrieving S is to improve the reliability of satellite SSS especially at middle and high latitudes, by developing advanced algorithms, combining both sensors, or weighing between accuracy and resolutions.

关键词： soil moisture and ocean salinity Aquarius sea surface salinity vertical retrieval feature resolution

AN ANALYSIS OF CLIMATE IN THE LUSHAN GLACIAL STAGE

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Science China Chemistry 1983年第9期26卷 961-970页

作者：傅逸贤 Nanjing institute of meteorology

Deduction is made in this paper for the temperature and snowfall in the mountainous areas of East China daring the Quaternary Ice Age based on climatological theories. At that time solar radiation in the summer half year was weak and the altitude of the Qinghai-Xizang Plateau was low so that the role of the Plateau as a heat "island" to the atmosphere and the associated Qinghai-Xizang high were both weaker than they are today. In addition, the western Pacific subtropical high was weak, hence, the temperature in the summer half year, especially in middle summer, was far lower than it is now while the polar front in the winter half year was strong and to the south, which is a favorable factor for the snowfall in this *** made for ice-snow mass balance show that the amount of snowfall was likely to exceed that of snow ablation in north-facing valleys.

关键词： AN ANALYSIS OF CLIMATE IN THE LUSHAN GLACIAL STAGE over

Asymmetric Distribution of Convection in Tropical Cyclones over the Western North Pacific Ocean

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Advances in Atmospheric Sciences 2016年第11期33卷 1306-1321页

作者： Lu YANG Jianfang FEI Xiaogang HUANG Xiaoping CHENG Xiangrong YANG Juli DING Wenli SHI institute of meteorology and Oceanography PLA University of Science and Technology

Forecasts of the intensity and quantitative precipitation of tropical cyclones（TCs） are generally inaccurate, because the strength and structure of a TC show a complicated spatiotemporal pattern and are affected by various factors. Among these, asymmetric convection plays an important role. This study investigates the asymmetric distribution of convection in TCs over the western North Pacific during the period 2005–2012, based on data obtained from the Feng Yun 2（FY2）geostationary satellite. The asymmetric distributions of the incidence, intensity and morphology of convections are *** show that the PDFs of the convection occurrence curve to the azimuth are sinusoidal. The rear-left quadrant relative to TC motion shows the highest occurrence rate of convection, while the front-right quadrant has the lowest. In terms of intensity, weak convections are favored in the front-left of a TC at large distances, whereas strong convections are more likely to appear to the rear-right of a TC within a 300 km range. More than 70% of all MCSs examined here are elongated systems, and meso-β enlongated convective systems（MβECSs） are the most dominant type observed in the outer region of a TC. Smaller MCSs tend to be more concentrated near the center of a TC. While semi-circular MCSs [MβCCSs, MCCs（mesoscale convective complexes）] show a high incidence rate to the rear of a TC, elongated MCSs [MβECSs, PECSs（persistent elongated convective systems）] are more likely to appear in the rear-right quadrant of a TC within a range of 400 km.

关键词： convection Tropical convective asymmetric tropical mesoscale elongated typhoon likely storm

Development of an Integrated Vertical-Slantwise Convective Parameterization Scheme and Its Associated Numerical Experiments

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Acta meteorologica Sinica 2011年第4期25卷 405-418页

作者：费建芳伍荣生黄小刚王元程小平 institute of meteorology PLA University of Science & Technology institute of Atmospheric Sciences Nanjing University

An integrated vertical-slantwise convective parameterization scheme, based on the vertical Kuo-Anthes and the slantwise Nordeng convective parameterization schemes, is introduced into the MM5 model. By employing the MM5 model with the proposed scheme, numerical simulations of a snowstorm event that occurred over southern China on 28-29 January 2008 and of Typhoon Haitang （2005） are conducted. The results indicate that during the snowstorm event, the atmosphere was convectively stable in the vertical direction but with conditional symmetric instability （CSI） in the lower troposphere, and when the area of CSI developed and extended to upper levels, strong rising motion occurred and triggered the release of large amount of energy, producing enhanced convective precipitation with the total precipitation much closer to the observation. The development and strengthening of CSI corresponded to changes in the intensity of snowfall, convergence, and ascending motions of air, revealing that CSI was responsible for the initiation and growth of the snowstorm. The results from a 72-h explicit simulation of Typhoon Haitang indicate that CSI occurred mainly at lower levels with a well-defined spiral structure, and it tended to have a larger impact on the intensity of typhoon than on its track. The minimum pressure at the typhoon center for the 72-h runs with the integrated vertical-slantwise convective parameterization scheme was on average 3 hPa （maximum 8 hPa） lower than that from the runs with only the vertical cumulus parameterization scheme. Introducing the influence of CSI into the model has improved the warm core structure at the middle and upper levels of the typhoon, with stronger and persistent upward motions causing increased precipitation, and the latent heat released through convection in turn made the typhoon develop further.

关键词： snowstorm typhoon conditional symmetric instability (CSI) the integrated vertical-slantwise convective parameterization scheme numerical simulation

Comparison of Wind Sat and buoy-measured ocean products from 2004 to 2013

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Acta Oceanologica Sinica 2016年第1期35卷 67-78页

作者： ZHANG Lei SHI Hanqing DU Huadong ZHU Enze ZHANG Zhihua FANG Xun institute of meteorology and Oceanography PLA University of Science and Technology

To evaluate the ocean surface wind vector and the sea surface temperature obtained from WindSat, we compare these quantities over the time period from January 2004 to December 2013 with moored buoy measurements. The mean bias between the WindSat wind speed and the buoy wind speed is low for the low frequency wind speed product （WSPD_LF）, ranging from -0.07 to 0.08 m/s in different selected areas. The overall RMS error is 0.98 m/s for WSPD_LF, ranging from 0.82 to 1.16 m/s in different selected regions. The wind speed retrieval result in the tropical Ocean is better than that of the coastal and offshore waters of the United States. In addition, the wind speed retrieval accuracy ofWSPD LF is better than that of the medium frequency wind speed product. The crosstalk analysis indicates that the WindSat wind speed retrieval contains some cross influences from the other geophysical parameters, such as sea surface temperature, water vapor and cloud liquid water. The mean bias between the WindSat wind direction and the buoy wind direction ranges from -0.46° to 1.19° in different selected regions. The overall RMS error is 19.59° when the wind speed is greater than 6 m/s. Measurements of the tropical ocean region have a better accuracy than those of the US west and east coasts. Very good agreement is obtained between sea surface temperatures of WindSat and buoy measurements in the tropical Pacific Ocean; the overall RMS error is only 0.36℃, and the retrieval accuracy of the low latitudes is better than that of the middle and high latitudes.

关键词： WindSat polarimetric microwave radiometer wind vector sea surface temperature validation

Use of Surface Observations to Estimate Upper Air Humidity for the Objective Analysis of Relative Humidity over Indian Region

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Advances in Atmospheric Sciences 1990年第4期7卷 491-501页

作者： S.K.Sinha D.R.Talwalkar S.G.Narkhedkar P.L.Kulkarni S.Nair S.Rajamani Indian institute of Tropical meteorology Pune-411008 India Indian Institute of Tropical Meteorology Pune-411008 IndiaIndian Institute of Tropical Meteorology Pune-411008 IndiaIndian Institute of Tropical Meteorology Pune-411008 IndiaIndian Institute of Tropical Meteorology Pune-411008 IndiaIndian Institute of Tropical Meteorology Pune-411008 India

In the present study objective analyses of relative humidity (RH) at surface and at the levels of 850, 700 and 500 hPa have been made using Gandin's (1963) optimum interpolation scheme. As the horizontal resolution of the radiosonde stations is rather inadequate for upper air humidity analysis, a scheme has been developed, following Rasmussen (1982) to estimate the upper air RH from the surface observations like surface RH, present weather and cloud cover. The relative humidities at the levels 850, 700 and 500 hPa were related to the surface observations through three separate regression relations. The RH values at 850, 700 and 500 hPa levels were estimated from the surface RH, cloud coverage and present weather using the above regression relations and subsequently the objective analyses at 00 GMT for the period from 4 July to 8 July 1979, were made using these estimated data along with the observed radiosonde data. Objective analyses were also made for the same period using only the radiosonde data for comparison to study the impact of those estimated data. Root mean square errors were computed for all the five days by interpolating RH at the observing stations from the objectively analysed field and comparing them with the actually observed RH to examine how best the analyses (with and without estimated data) fitted the observations. Lastly they were compared with satellite cloud pictures. This study shows that the estimated upper air RH values have positive impact on the analysis of upper air RH and could be used over radiosonde data sparse region and even over oceanic regions.

关键词： In RH over

Detecting Intensity Evolution of the Western North Pacific Super Typhoons in 2016 Using the Deviation Angle Variance Technique with FY Data

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Journal of Meteorological Research 2019年第1期33卷 104-114页

作者： Meng YUAN Wei ZHONG institute of meteorology and Oceanography National University of Defense Technology

This paper analyzes the complete lifecycle of super typhoons in 2016 in the western North Pacific(WNP) using the deviation angle variance technique(DAV-T). Based on the infrared images from Fengyun(FY) satellites, the DAV-T enables quantification of the axisymmetry of tropical cyclones(TCs) by using the DAV values; and thus, it helps improve the capability of TC intensity estimation. Case analyses of Super Typhoons Lionrock and Meranti were performed to explore the distribution characteristics of the DAV values at the various stages of TC evolution. The results show that the minimum DAV values(i.e., map minimum values: MMVs) gradually decreased and their locations constantly approached the circulation center with enhancement of the TC organization; however, when a ring or disk structure was formed around a TC, significant changes in MMV locations were no longer observed. Nonetheless,when large-scale non-closed deep convective cloud clusters appeared at the early stage or the dissipation stage of the typhoon, the axisymmetry of the TC was poor and the MMV locations tended to lie in the most convective region rather than in the TC circulation center. Overall, the MMVs and their locations, respectively, exhibited a strong correlation with the TC intensity and circulation center, and the correlation increased as the TCs became stronger. Combined with the China Meteorological Administration BestTrack dataset(CMA-BestTrack), statistical analysis of all research samples reveals that the correlation coefficient between the MMVs and maximum surface wind speeds(Vmax) was –0.80; the root mean square error(RMSE) of relative distance between the MMV locations and TC centers was 140.3 km; and especially, when the samples below the tropical depression(TD) intensity were removed, the RMSE of the relative distance decreased dramatically to 95.0 km. The value and location of the MMVs could be used as important indicators for estimating TC intensity and center.

关键词： deviation angle variance technique(DAV-T) axisymmetry super typhoon Fengyun(FY) satellites

Some Experiments with Multivariate Objective Analysis Scheme of Heights and Winds Using Optimum Interpolation

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Advances in Atmospheric Sciences 1992年第4期9卷 431-440页

作者： S.K.Sinha S.G.Narkhedkar D.R.Talwalkar S.Rajamani Indian institute of Tropical meteorology Pune 411008 IndiaIndian Institute of Tropical Meteorology Pune 411008 IndiaIndian Institute of Tropical Meteorology Pune 411008 IndiaIndian Institute of Tropical Meteorology Pune 411008 India

A two-dimensional, multitvariate objective analysis scheme for simultaneous analysis of geopotential height and wind fields has been developed over Indian and adjoining region for use in numerical weather prediction. The height-height correlations calculated using daily data of four July months (1976-1979), are used to derive the other autocorrelations and cross-correlations assuming geostropic relationship. A Gaussian function is used to model the autocorrelation function. Since the scheme is multivariate the regression coefficients (weights) are *** the equator, the geostrophic approximation relating mass and wind is decoupled in a way similar to Bergman (1979). The objective analyses were made over Indian and adjoining region for 850, 700, 500, 300 and 200 hPa levels for the period from 4 July to 8 July 1979, 12 GMT. The analyses obtained using multivariate optimum interpolation scheme depict the synoptic situations satisfactorily. The analyses were also compared with the FGGE analyses (from ECMWF) and also with the station observations by computing the root mean square (RMS) errors and the RMS errors are comparable with those obtained in other similar studies.

关键词： In Some Experiments with Multivariate Objective Analysis Scheme of Heights and Winds Using Optimum Interpolation

Temperatures and Winds over Tropical Middle Atmosphere during Two Contrasting Summer Monsoons, 1975 and 1979

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Advances in Atmospheric Sciences 1989年第3期6卷 325-334页

作者： B.K.Mukherjee C.P.Kulkarni K.Indira K.K.Dani Indian institute of Tropical meteorology Pune-411005IndiaIndian Institute of Tropical MeteorologyPune-411005IndiaIndian Institute of Tropical MeteorologyPune-411005IndiaIndian Institute of Tropical MeteorologyPune-411005India

Using the monthly geopotential heights and winds for 700 and 200 hPa for India during July and August, and the weekly M-100 Soviet rocketsonde temperature and wind data for Thumba (8.5 ° N, 76.9 ° E) during the last week of June and the first week of September for the two contrasting summer monsoon years 1975 (a very strong monsoon year) and 1979 (a very weak monsoon year), a study has been made to examine the mean circulation features of the troposphere over India, and the structures of the temperatures and the winds of the middle atmosphere over Thumba. The study suggested that the axis of the monsoon trough (AMT) at 700 hPa shifted southward in 1975 and northward towards the foothills of the Himalayas in 1979, from its normal position. Superimposed on the low-pressure area (AMT) at 700 hPa, a well-defined divergence was noticed at 200 hPa over the northern India in *** mean temperatures at 25,50 and 60 km (middle atmosphere) over Thumba were cooler in 1975 than in 1979. While a cooling trend in 1975 and warming trend in 1979 were observed at 25 and 50 km, a reversed picture was noticed at 60 km. There was a weak easterly / westerly (weak westerly phase) zonal wind in 1975 and a strong easterly zonal wind in 1979. A phase reversal of the zonal wind was observed at 50 km. A tentative physical mechanism was offered, in terms of upward propagation of the two equatorially trapped planetary waves i.e. the Kelvin and the mixed Rossby-gravity waves, to explain the occurrence of the two spells of strong warmings in the mesosphere in 1975.

关键词： over In and 1979 Temperatures and Winds over Tropical Middle Atmosphere during Two Contrasting Summer Monsoons