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| 1 | A quantitative approach to monitoring new sand cay migration in Nansha Islands显示文摘Sand cay is a special kind of islet formed by coral detritus and bioclast, which is common in Nansha Islands of China. Some sand cays play an important role in ocean strategy and economy, but surprisingly we know little about them, especially those recently formed sand cays. In this research, we monitor migration of a new sand cay in Nanxun Jiao(Gaven Reef) using a series of Quick Bird and World View-2 satellite images between June 2006 and August 2013. We conduct a regression between migration distance and wind observational data to examine the migration patterns of the new sand cay. The migration distance is calculated based on the sand cay locations extracted based on Normalized Difference Water Index(NDWI). The wind observational data downloaded from NOAA are reformed into four wind direction vectors. Based on the results of regression, we concluded that the migration of the new sand cay on Nanxun Jiao was significantly associated with the east, west and north wind.East wind was the main influence factor of the migration; its impact strength was almost twice as the west and north wind. The south wind has little effect on the migration of the sand cay, which is partly blocked by the artificial structure in the south. | ZHU Haitian JIANG Xingwei MENG Xuelian FENG Qian CUI Songxue LIANG Chao | 2016 | Acta Oceanologica Sinica2016，35，3： | 9 |
| 2 | The study on an Antarctic sea ice identification algorithm of the HY-2A microwave scatterometer data显示文摘An Antarctic sea ice identification algorithm on the HY-2A scatterometer(HSCAT) employs backscattering coefficient(σ0) and active polarization ratio(APR) for a preliminary sea ice identification.Then standard deviation(STD) filtering and space filtering are carried out.Finally,it is used to identify sea ice.A process uses a σ0,STD threshold and an APR as sea ice indicators.The sea ice identification results are verified using the sea ice distribution data of the ASMR2 released by the National Snow and Ice Data Center as a reference.The results show very good consistence of sea ice development trends,seasonal changes,area distribution,and sea ice edge distribution of the sea ice identification results obtained by this algorithm relative to the ASMR2 sea ice results.The accuracy of a sea ice coverage is 90.8% versus the ASMR2 sea ice results.This indicates that this algorithm is reliable. | ZOU Juhong ZENG Tao GUO Maohua CUI Songxue | 2016 | Acta Oceanologica Sinica2016，35，9： | 4 |
| 3 | A high wind geophysical model fuction for Quik SCAT wind retrievals and application to Typhoon IOKE显示文摘The geophysical model function(GMF) describes the relationship between a backscattering and a sea surface wind, and enables a wind vector retrieval from backscattering measurements. It is clear that the GMF plays an important role in an ocean wind vector retrieval. The performance of the existing Ku-band model function QSCAT-1 is considered to be effective at low and moderate wind speed ranges. However, in the conditions of higher wind speeds, the existing algorithms diverge alarmingly. owing to the lack of in situ data required for developing the GMF for the high wind conditions, the QSCAT-1 appears to overestimate the s0, which results in underestimating the wind speeds. Several match-up Quik SCAT and special sensor microwave/imager(SSM/I)wind speed measurements of the typhoons occurring in the west Pacific Ocean are analyzed. The results show that the SSM/I wind exhibits better agreement with the 'best track' analysis wind speed than the Quik SCAT wind retrieved using QSCAT-1. On the basis of this evaluation, a correction of the QSCAT-1 model function for wind speed above 16 m/s is proposed, which uses the collocated SSM/I and Quik SCAT measurements as a training set,and a neural network approach as a multiple nonlinear regression technologytechnology.In order to validate the revised GMF for high winds, the modified GMF was applied to the Quik SCAT observations of Hurricane IOKE.The wind estimated by the Quik SCAT for Typhoon IOKE in 2006 was improved with the maximum wind speed reaching 55 m/s. An error analysis was performed using the wind fields from the Holland model as the surface truth. The results show an improved agreement with the Holland model wind when compared with the wind estimated using the QSCAT-1. However, large bias still existed, indicating that the effects of rain must be considered for further improvement. | ZOU Juhong ZENG Tao CUI Songxue | 2015 | Acta Oceanologica Sinica2015，34，7： | 1 |
| 4 | Effect of Particle Shape on Dust Shortwave Direct Radiative Forcing Calculations Based on MODIS Observations for a Case Study显示文摘Assuming spheroidal and spherical particle shapes for mineral dust aerosols,the effect of particle shape on dust aerosol optical depth retrievals,and subsequently on instantaneous shortwave direct radiative forcing(SWDRF) at the top of the atmosphere(TOA),is assessed based on Moderate Resolution Imaging Spectroradiometer(MODIS) data for a case study.Specifically,a simplified aerosol retrieval algorithm based on the principle of the Deep Blue aerosol retrieval method is employed to retrieve dust aerosol optical depths,and the Fu–Liou radiative transfer model is used to derive the instantaneous SWDRF of dust at the TOA for cloud-free conditions.Without considering the effect of particle shape on dust aerosol optical depth retrievals,the effect of particle shape on the scattering properties of dust aerosols(e.g.,extinction efficiency,single scattering albedo and asymmetry factor) is negligible,which can lead to a relative difference of at most 5% for the SWDRF at the TOA.However,the effect of particle shape on the SWDRF cannot be neglected provided that the effect of particle shape on dust aerosol optical depth retrievals is also taken into account for SWDRF calculations.The corresponding results in an instantaneous case study show that the relative differences of the SWDRF at the TOA between spheroids and spheres depend critically on the scattering angles at which dust aerosol optical depths are retrieved,and can be up to 40% for low dust-loading conditions. | FENG Qian CUI Songxue ZHAO Wei | 2015 | Advances in Atmospheric Sciences2015，32，9： | 0 |
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