普里兹湾附近物理海洋学研究进展

本文主要利用近三十年来的文献资料 ,概述了普里兹湾及其邻近洋区物理海洋学研究的进展。其主要内容包括 :1 .开展普里兹湾及其邻近海域物理海洋学研究的科学意义 ;2 .现场考察的综述 ;3.水团分布及其物理特性 ;4.海流观测及其分析 ,与此同时 ,说明了在上述各个方面的研究成果和最新进展。最后指出了目前在有关的观测和研究工作中存在的不足 ,以及今后改进的建议。     

Detection of marine aerosols with IRS P4-Ocean Colour Monitor

The atmospheric correction bands 7 and 8 (765nm and 865nm respectively) of the Indian Remote Sensing Satellite IRS P4-0CM (Ocean Colour Monitor) can be used for deriving aerosol optical depth (AOD) over the oceans. A retrieval algorithm has been developed which computes the AOD using band 7 data by treating the ocean surface as a dark background after removing the Rayleigh path radiance in the sensor-detected radiances. This algorithm has been used to detect marine aerosol distributions at different coastal and offshore locations around India. A comparison between OCM derived AOD and the NOAA operational AOD shows a correlation ∼0.92 while that between OCM derived AOD and the ground-based sun photometer measurements near the coast of Trivandrum shows a correlation of ∼0.90.     

Assessment of three numerical solution strategies for gravity field recovery from GOCE satellite gravity gradiometry implemented on a parallel platform

 The recovery of a full set of gravity field parameters from satellite gravity gradiometry (SGG) is a huge numerical and computational task. In practice, parallel computing has to be applied to estimate the more than 90 000 harmonic coefficients parameterizing the Earth's gravity field up to a maximum spherical harmonic degree of 300. Three independent solution strategies (preconditioned conjugate gradient method, semi-analytic approach, and distributed non-approximative adjustment), which are based on different concepts, are assessed and compared both theoretically and on the basis of a realistic-as-possible numerical simulation regarding the accuracy of the results, as well as the computational effort. Special concern is given to the correct treatment of the coloured noise characteristics of the gradiometer. The numerical simulations show that the three methods deliver nearly identical results—even in the case of large data gaps in the observation time series. The newly proposed distributed non-approximative adjustment approach, which is the only one of the three methods that solves the inverse problem in a strict sense, also turns out to be a feasible method for practical applications. Received: 17 December 2001 / Accepted: 17 July 2002 Acknowledgments. We would like to thank Prof. W.-D. Schuh, Institute of Theoretical Geodesy, University of Bonn, for providing us with the serial version of the PCGMA algorithm, which forms the basis for the parallel PCGMA package developed at our institute. This study was partially performed in the course of the GOCE project `From E?tv?s to mGal+', funded by the European Space Agency (ESA) under contract No. 14287/00/NL/DC. Correspondence to: R. Pail     

Quasi-conservative behaviour of Be in deep waters of the Weddell Sea and the Atlantic sector of the Antarctic Circumpolar Current

We present the first transect of dissolved ¹⁰Be depth profiles across the Antarctic Circumpolar Current (ACC) in the Atlantic sector. North of the Polar Front the ¹⁰Be concentrations increase continuously from very low values at the surface to values of up to 1600 atoms/g at depth. Deep water ¹⁰Be concentrations of particular water masses are consistent with earlier results obtained further north. South of the Polar Front and in the Weddell Sea the distribution of ¹⁰Be is also characterised by low surface concentrations but below 1000 m depth the concentrations are relatively constant and significantly higher (up to 2000 atoms/g) than further north, probably as a result of mixing and advection of water masses of Pacific origin. Overall the deep water ¹⁰Be distribution is obviously not significantly affected by scavenging processes or ice melt and comparison with the density distribution suggests that ¹⁰Be can be viewed as a quasi-conservative tracer. This provides a tool for an improved understanding of the behaviour of other more particle reactive trace metals in the Southern Ocean such as ²³⁰Th: in deep waters north of the ACC/Weddell Gyre boundary (AWB) ¹⁰Be/²³⁰Th has a relatively constant value (1.7±0.3×10⁹ atoms/dpm) over a wide density range whereas south of the AWB the ratio is significantly lower (1.1±0.2×10⁹ atoms/dpm). This normalisation to ¹⁰Be corroborates that ²³⁰Th is enriched by 50% due to accumulation south of the AWB as a consequence of minimal particulate fluxes. The quasi-conservative behaviour deduced from our results also implies that ¹⁰Be can only be used as a tracer for Southern Ocean particle fluxes in the past if ocean circulation patterns and water mass residence times did not change significantly.     

北太平洋冬季阻塞性高压对船舶西行航线的影响*

通过对近10年北太平洋冬季阻塞性高压的建立、维持及崩溃的天气形势分析，结合船舶气象导航的原理、气象航线的设计以及影响航线选择的因素，指出了有利于北太平洋冬季西行高纬度航线的阻塞高压形式，为船舶西行选择高纬度航线提供了气象理论依据。     

厄尔尼诺现象的构造基础与激发因素

北太平洋对北极的半封闭状态和南太平洋对南极的开放状态是厄尔尼诺事件发生的构造基础，它导致北太平洋海表热能的积累和周期性向南太平洋输送，强潮汐振荡和火山喷发是其激发因素。     

INDIAN OCEAN DIPOLE AND ITS RELATIONSHIP WITH ENSO MODE

Near 100-year observed data sets are analyzed, and the results show that the variation of seasurface temperature(SST)in the equatorial Indian Ocean has a feature as a dipole oscillation.Thesituation of the dipole oscillation mainly shows the positive phase pattern(higher SST in the westand lower SST in the east than normal)and the negative phase pattern(higher SST in the east andlower SST in the west).The amplitude of the positive phase is larger than that of the negativephase.The dipole is stronger in September—November and weaker in January—April than inother months.It principally shows obviously inter-annual(4—5 year period)and inter-decadalvariation(25—30 year period).Although the Indian Ocean dipole in the individual year seems tobe independent of ENSO in the equatorial Pacific Ocean,in general,the Indian Ocean dipole hasobviously negative correlation with the Pacific Ocean “dipole”(similar to the inverse phase ofENSO).The atmospheric zonal(Walker) circulation is fundamental for relating the two dipoles toeach other.     

Multi-technique monitoring of ocean tide loading in northern France

We have organised afield study of ocean tide loading in the northwestern part of France, where tidal amplitudes are known to be among the highest in the world. GPS and gravimetric techniques have already proved their capability to measure such weak and high-frequency signals. In this study, these classical observations are complemented with less usual techniques, such as tiltmeter and Satellite Laser Ranging (SLR) measurements. We present here the preliminary results for a common period of observations spanning from 12–19 May 2004. Additional measurements from the French Transportable Laser Ranging Station (FTLRS) were available during September and October 2004. Observation residuals are computed as the difference between the observed and the predicted time signals. We obtain small RMS residuals for GPS measurements (2.5/3.1/4.5 mm for the eastward, northward and upward components), for absolute and relative gravimetry (9 nm/s² and 13 nm/s²) and for tiltmeters (0.05 μrad for EW component). We also fit the amplitude of the main M2 tidal constituent to FTLRS observations and we find a value of 3.731 cm, which is comparable to the theoretical value.     

Simulated Relationship between Wintertime ENSO and East Asian Summer Rainfall: From CMIP3 to CMIP6

El Ni?o-Southern Oscillation(ENSO)events have a strong influence on East Asian summer rainfall(EASR).This paper investigates the simulated ENSO-EASR relationship in CMIP6 models and compares the results with those in CMIP3 and CMIP5 models.In general,the CMIP6 models show almost no appreciable progress in representing the ENSO-EASR relationship compared with the CMIP5 models.The correlation coefficients in the CMIP6 models are relatively smaller and exhibit a slightly greater intermodel diversity than those in the CMIP5 models.Three physical processes related to the delayed effect of ENSO on EASR are further analyzed.Results show that,firstly,the relationships between ENSO and the tropical Indian Ocean(TIO)sea surface temperature(SST)in the CMIP6 models are more realistic,stronger,and have less intermodel diversity than those in the CMIP3 and CMIP5 models.Secondly,the teleconnections between the TIO SST and Philippine Sea convection(PSC)in the CMIP6 models are almost the same as those in the CMIP5 models,and stronger than those in the CMIP3 models.Finally,the CMIP3,CMIP5,and CMIP6 models exhibit essentially identical capabilities in representing the PSC-EASR relationship.Almost all the three generations of models underestimate the ENSO-EASR,TIO SST-PSC,and PSC-EASR relationships.Moreover,almost all the CMIP6 models that successfully capture the significant TIO SST-PSC relationship realistically simulate the ENSO-EASR relationship and vice versa,which is,however,not the case in the CMIP5 models.