HY-2 扫描辐射计风速数据产品与平台基观测数据的比较研究

基于南海北部PY30-1平台上2012年2月至9月测风仪观测的风速数据,开展了HY-2扫描辐射计风速数据比较研究。选取时空匹配窗口为5 min和25 km,利用HY-2扫描辐射计RM 100,70和35 km分辨率3种风速数据,分别与平台观测数据进行了比较。比较结果表明:在南海北部海域,HY-2扫描辐射计100 km分辨率风速和平台观测风速的均方根偏差为3.86 m/s;70 km分辨率风速和平台观测风速的均方根偏差为10.52 m/s;35 km分辨率风速和平台观测风速的均方根偏差为5.54 m/s。还进一步比较了有雨和无雨两种情况下HY-2扫描辐射计和平台数据的偏差,结果表明:有雨和无雨条件下都是100 km分辨率的数据偏差最小。这为在我国南海北部海域应用HY-2扫描辐射计的风速数据产品的选择提供了依据。     

Assessment of the initial sea surface temperature product of the scanning microwave radiometer aboard on HY-2 satellite

HY-2 satellite is the first satellite for dynamic environmental parameters measurement of China,which was launched on 16th August 2011.A scanning microwave radiometer（RM） is carried for sea surface temperature（SST）,sea surface wind speed,columnar water vapor and columnar cloud liquid water detection.In this paper,the initial SST product of RM was validated with in-situ data of National Data of Buoy Center（NDBC） mooring and Argo buoy.The validation results indicate the accuracy of RM SST is better than 1.7 C.The comparison of RM SST and WindSat SST shows the former is warmer than the latter at high sea surface wind speed and the difference between these SSTs is depend on the sea surface wind speed.Then,the relationship between the errors of RM SST and sea surface wind speed was analyzed using NDBC mooring measurements.Based on the results of assessment and errors analysis,the suggestions of taking account of the affection of sea surface wind speed and using sea surface wind speed and direction derived from the microwave scatteromter aboard on HY-2 for SST product calibration were given for retrieval algorithm improvement.     

Eddy activities of the surface layer in the western North Pacific detected by satellite altimeter and radiometer

Geosat radar altimeter data during the first year (from November 1986 to November 1987) of its Exact Repeat Mission are analyzed to estimate the eddy kinetic energy and propagation characteristics of anomalies of sea surface dynamic topography (SSDT) for the western North Pacific. SSDT anomalies are compared with anomalies of sea surface temperature (SST) derived from NOAA satellite radiometer data. The eddy kinetic energy (K _e ) is large in the Kuroshio stationary meander region and Kuroshio Extension region. In the downstream region of the Kuroshio Extension,K _e is especially large on the upstream and downstream sides of prominent bathymetric features. In the interior region of the subtropical gyre is found a zonal tongue of largeK _e at around 20–20°N. Westward propagation is dominant in the SSDT and SST anomaly field at mid-latitudes. Longitude-time lag correlation diagrams reveal the coincidence of SSDT and SST anomalies statistically, which fact suggests the baroclinic nature of the anomalies. Zonal phase speeds of SSDT anomalies are approximately equal to the theoretical speeds of baroclinic first-mode long Rossby waves, but the meridional variation of observed phase speeds does not follow the simple theoretical variation of decreasing speeds monotonously with increasing latitudes.     

HY-2B卫星载荷联合观测海面阵风的一种反演方法

国内外对海上阵风的研究并不多,且大多集中在阵风预报和应用研究方面,对于海洋阵风数据的获取技术未见文献系统论述。本文利用HY-2B卫星雷达高度计观测的后向散射系数,结合校正微波辐射计观测的亮度温度信息,提出联合反演阵风风速的方法。两个遥感载荷联合反演得到的阵风风速与2019–2021年美国国家浮标数据中心（NDBC）浮标数据进行真实性检验,结果显示：阵风风速均方根误差（RMSE）为0.98 m/s,相关系数为0.82;基于本方法利用国外同类卫星Jason-3得到的阵风风速与2016–2018年NDBC浮标数据的RMSE为0.96 m/s,相关系数为0.88。本文在HY-2B卫星雷达高度计海面风速观测的基础上,纳入同一卫星平台校正微波辐射计的同步观测信息联合实现了海面阵风的观测,数据的比对结果证明文中方法具有较高的观测精度。同时,该方法对于具有相同观测体制的国内外卫星也适用。     

Ground-based measurements of total ozone content by the infrared method

To interpret the ground-based measurements of the spectra of direct solar infrared radiation with the help of a Brucker Fourier-spectrometer, a technique for determining the total ozone content (TOC) was developed and implemented. The TOC was determined using six spectral intervals of an ozone-absorption band of 9.6 μm and the shortwave panel of a carbon-dioxide-absorption band of 15 μm, where the impact of other atmospheric parameters on the measured solar radiation was reduced to a minimum. The potential errors of the infrared method for determining the TOC for the chosen spectral scheme with the influence of measurement errors and vertical profiles of temperature are less than 1% for different signal-to-noise ratios and zenith angles of the sun. We analyzed 269 high-resolution (0.005–0.008 cm^?1) spectra of solar infrared radiation measured in Peterhof over 52 days from March to November, 2009. The resulting values of TOC were compared with the results of independent ground-based TOC measurements in Voeikovo (Main Geophysical Observatory) using a Dobson spectrophotometer and an M-124 ozonometer, as well as with the Ozone Monitoring Instrument (OMI) satellite data. The mean errors between the results of TOC measurements with the help of the three ground-based probes constitute no more than 0.4%. The rms errors between data obtained by the Brucker spectrometer and the given satellite and ground-based probes constitute 3–4%. A comparison between different series of measurements indicated that the upper estimate for the error of TOC measurements by the Brucker spectrometer was 2.5–3% (when the possible spatial and temporal errors in measurements are disregarded). An analysis of the diurnal variations in the TOC measurements for stable atmospheric conditions yields an upper estimate of ～3 DU (around 1%) for the random component of error in TOC measurements by the Brucker spectrometer.     

A new method for continuous measurements of O2 in surface water in combination with pCO2 measurements: Implications for gas phase equilibration

An autonomous system for the recording of the surface water pCO₂ in the Baltic Sea was complemented by a module for continuous O₂ measurements. An optical O₂ sensor was used and in analogy to the determination of the pCO₂, the pO₂ was determined in the headspace of an equilibrator. By this procedure the automatic periodic calibration was considerably facilitated and biofouling was avoided. Uncertainties were associated with the use of a vented equilibrator. Due to the continuous pressure equalization with the ambient atmosphere, the headspace partial pressure of any gas (e.g. pO₂, pCO₂) reflects a steady state that may deviate substantially from the equilibrium. To calculate the true equilibrium pO₂ and thus the O₂ concentration in the water sample, we derived an equation that is based on the measurement of the headspace O₂ mol fraction, x_O2, and on the assumption that the surface water was saturated with atmospheric N₂ and Ar. Model calculations indicated that deviations from this assumption are less then 2% for most of the year. The combined pO₂/pCO₂ measurement system was deployed in July 2005 on a cargo ship that commutes regularly between the southwestern Baltic Sea and the Gulf of Finland. First results showed a reasonable agreement with O₂ data obtained at a measurement platform in the vicinity of the ship's track. The spatial resolution of the O₂ measurements was similar to that of the pCO₂ system and allowed the identification of small scale (< 1 nautical mile) biogeochemical and hydrographical inhomogeneities.     

Peculiarities of distribution of oil polution in the Southeastern Baltic by satellite data and in situ measurements

The results of satellite monitoring of oil pollution of the sea surface and field measurements of the concentration of oil products in the water column and bottom sediments for the first time allowed the establishment of a relation between the surface pollution from ships and the general characteristics of spatial and temporal distribution of oil products in the Southeastern Baltic Sea. Areas with increased concentrations of oil products in the surface and bottom layers were determined in the southeastern Baltic Sea. The basic directions of pollution spread, which are consistent with the main direction of annual mean transport of substances in the Gdansk Basin, are determined.     

Individual responsibility for the oceans? An evaluation of marine citizenship by UK marine practitioners

In recent times, the governance of the marine environment has evolved from being primarily top down and state directed to being more participatory and community based. This paper proposes that an extension of this trend would be the inculcation of a societal sense of marine citizenship to deliver the sustainable management and protection of the marine environment through enhanced individual involvement in policy development and implementation. The potential role of marine citizenship in UK marine governance was examined by surveying UK marine practitioner’s views on both the current and future role of marine citizenship. Observations from this study identified three key factors for discussion including conflicting opinions over the implementation of marine citizenship into policy; that marine-focused education and a sense of personal attachment are integral to the development of marine citizenship; and that as yet, the potential implications of an enhanced sense of marine citizenship are uncertain. This research highlights the recognition amongst marine practitioners that higher levels of citizen involvement in the management of the marine environment would greatly benefit the marine environment, with additional benefits possible through an increased sense of marine citizenship.     

A method for the quantitative estimation of bacteria from mangrove sediments

A simple and rapid method for the quantitative extraction of bacteria from high silt/clay-content muds associated with mangrove swamps is described. Mud samples are homogenized in filtered sea water and the supernatant is diluted and stained with Acridine Organge. The stained material is trapped on a 0·45 μm membrane filter and bacteria are counted under a fluorescence microscope. Samples may be pre-fixed in 5% formalin if they cannot be examined immediately.     

Analysis of satellite observations of the tropospheric NO<Subscript>2</Subscript> content over the Moscow region

The tropospheric NO₂ content over the Moscow region is analyzed on the basis of data of the satellite Ozone Monitoring Instrument (OMI) in the period 2004–2009. The spatial distributions of NO₂ are presented, and some of their features are interpreted. The characteristics of the seasonal and weekly cycles of NO₂ are described, as are its interannual and long-term variations. The relationship between the variabilities of the NO₂ content and the aerological parameters is investigated on different time scales. The mutual influence of regional pollution and meteorological regimes is discussed. The seasonal and weekly NO₂ cycles over Moscow are compared with those over the largest worldwide agglomerations.     

A Bayesian method for the estimation of return values of wave heights

Bayesian statistics offer a novel means of estimating return values of wave heights and hence of establishing design criteria for offshore structures. The Bayesian method has significant advantages over the classical method since it enables all types of uncertainty (physical, parameter, distribution) associated with the design wave prediction to be handled in a consistent manner in the same analysis.The basic principles of the Bayesian method for drawing inferences are outlined step-by-step. It is shown how Bayesian estimators of return values for wave heights are established by taking an expectation over all parameters and contending distributions. When the Bayesian procedure is applied to large data sets, such as wave data sets, computational difficulties could be encountered, making a “remedial” procedure necessary. However, the Bayesian procedure has been used successfully with wave data sets from the northern North Sea. Furthermore, the associated remedial procedure is such that the program can be made suitable for many existing computers, e.g. desk computers.     

210Pb method for estimating the rate of carbonate sand sedimentation

The plot of²¹⁰Pb activity against depth in carbonate sands on the Virgin Island Bank is a negative asymmetric hyperbolic curve. As depth increases, an initial rapid decrease in²¹⁰Pb activity caused by the decay of unsupported²¹⁰Pb and²²⁶Ra is followed by increasing activity as a result of²¹⁰Pb achieving equilibrium with ingrowing²³⁰Th. As this curve is time dependent, an estimate of the relative ages in carbonate sequences and the rates of net carbonate accumulation can be made. The ease of²¹⁰Pb activity determinations makes this procedure an attractive method in obtaining carbonate sand accumulation rates.     

利用TOPEX卫星高度计资料分析东中国海的风、浪场特征

利用TOPEX卫星高度计和日本气象厅浮标观测资料,对东中国海的有效波高和风速进行比较,分析了卫星高度计资料的有效性。利用有效波高和风速的3种概率密度函数分布,结合TOPEX卫星高度计资料,并采用最大似然方法对统计分布参数进行估计,结果表明,有效波高的对数-正态概率密度分布与观测资料的直方图在有效波高的整个范围内符合较好,风速的直方图与Weibul概率密度分布符合较好。同时,分析了有效波高大于4 m的巨浪在东中国海的时空分布特征,表明巨浪多出现在冬、秋两季,平均有效波高最大值出现在夏季,且主要分布在东中国海东南部。     

Long-term variation in the anticyclonic ocean circulation over the Zapiola Rise as observed by satellite altimetry: Evidence of possible collapses

The Zapiola Rise (ZR) is a singular sedimentary deposit about 1200 m in height and 1500 km in width located in the Argentine Basin. In situ and satellite observations have revealed the presence of an intense counterclockwise circulation around the feature, with a volume transport comparable to those of the major ocean currents. The existence of a very low-frequency variability of the transport associated with the anticyclonic circulation is documented for the first time. As the Zapiola anticyclonic circulation plays a significant role in the mixing of the strongly contrasted water masses of the South Atlantic, variations in the anticyclonic transport can have a major impact on the mixing, hence a role in global climate variability. The circulation was clearly anticyclonic in the periods 1993–1999 and 2002–2007. In contrast, the 1999–2001 period did not show evidence of an anticyclonic flow in the mean surface velocity field. Moreover, the analysis of the weekly fields during that period of time revealed a cyclonic pattern from time to time. Previous work has shown that the flow can be considered as purely barotropic over the ZR region. A 15-year time-series of the transport was produced using absolute altimeter-derived geostrophic velocities. The estimated transport presents high-frequency variability associated with mesoscale activity superimposed on a low-frequency signal. The amplitude of the estimated transport is in good agreement with the only in situ-derived estimation available (80 Sv, January 1993). The low-frequency signal presents a minimum during the period 1999–2001, further suggesting that at times the Zapiola anticyclonic flow may have significantly decreased in strength or even vanished. Possible causes of the low-frequency variability are discussed.     

Estimating the quality of the retrieval of the surface geostrophic circulation of the Black Sea by satellite altimetry data based on validation with drifting buoy measurements

Combined measurements of satellite altimeters make it possible to determine anomalies of the sea level of the Black Sea on a regular grid with a high spatial resolution 1/8°. In this work arrays of total geostrophic velocities of currents in the Black Sea basin are retrieved and compared with drifter measurements of current velocities for 1999–2007. The comparison is performed both for the whole array of drifter measurements (～110000 measurements) and individually for each drifter. To retrieve the velocities, two different arrays of mean dynamic topography (MDT) are used: synthetic and climatic mean dynamic topography. The comparison results demonstrate that using synthetic MDT is preferable for calculating geostrophic velocities. Velocities calculated by from satellite altimetry data agree with velocities obtained by in-situ data.     

Comparative analysis of the methods used for the determination of the optical parameters of waters in the black sea according to the data of satellite measurements

We demonstrate the possibility of determination of the spectral characteristics of absorption and backward scattering of light in the Black Sea according to the data of a SeaWiFS satellite device. We use specially selected data of observations obtained under favorable atmospheric conditions. It is shown that the results of calculations performed by using different methods are almost identical and weakly depend on the model parameters of the spectral course of the coefficients of absorption of light by yellow substance and its scattering by suspended particles.     

A two-channel method for retrieval of the Black Sea surface temperature from Landsat-8 measurements

Izvestiya, Atmospheric and Oceanic Physics - The present work is devoted to the development of a retrieval algorithm for the sea surface temperature from the two-channel measurements of the...     

A simplified hindcast method for the estimation of extreme storm surge events in semi-enclosed basins

Human presence, coastal erosion, and tourism activities are increasing the attention to coastal flooding risk. To perform risk assessments, long time series of observed or hindcast wave parameters and tide levels are then necessary. In some cases, only a few years of observation are available, so that observed extreme data are not always representative and reliable. A hindcast system aimed to reconstruct long time series of total tide levels may be of great help to perform robust extreme events analysis and then to protect human life, activities as well as to counteract coastal erosion by means of risk assessments. This work aims to propose a simplified method to hindcast storm surge levels time series in semi-enclosed basins with low computational costs. The method is an extension of a previous work of some of the authors and consists of a mixed approach in which the estimation of storm surge obtained by using the theory of linear dynamic system is corrected by using a statistical method. Both steps are characterized by low computational costs. Nevertheless, the results may be considered reliable enough also in view of the simplicity of the approach. The proposed method has been applied to the Manfredonia case study, a small village located in the Southern Adriatic Italian coast and often prone to coastal flooding events. The comparison of extreme events estimated on the basis of hindcast levels time series is satisfactorily similar to those estimated on the basis of observed tide series.