台风“麦莎”对西北太平洋近岸和离岸浮游植物叶绿素浓度的影响

研究了一个强度较强、移动较快的台风"麦莎"对浮游植物叶绿素a浓度的影响。利用卫星遥感资料,分析了台风"麦莎"经历前后海表叶绿素a浓度、海表温度(SST)和风速的变化,并初步讨论了近岸与离岸海域海表叶绿素a浓度在台风影响下的不同响应。结果表明,台风"麦莎"对东海海域产生了较大影响。台风路径附近的近岸、离岸海域SST响应都十分明显,台湾岛以东的离岸海域SST平均值约由台风前29°C降为台风中的26.4°C,台风后回升至最大值27.8°C。中国大陆东南沿海的近岸区域SST从台风前28.6°C达到台风中最低值26.1°C,台风后回升至最大值28°C。离岸海域海表叶绿素a浓度始终保持在较低的水平,由台风前0.049 mg·m-3增长至台风后0.077 mg·m-3,在台风期间保持缓慢增长的趋势。而近岸区域在强烈风场的影响下,近岸台风发生前存在的较高值区出现了急剧的衰减,由台风前1.83 mg·m-3降至台风中0.73 mg·m-3,并在台风过境后两天迅速回升至1.17mg·m-3。台风期间近岸海域海表叶绿素a浓度和风速呈负相关,台风后近岸海域叶绿素a浓度恢复至台风前水平时间很短,出现了与离岸海域截然不同的响应变化。     

台风“彩虹”对粤西近岸海表温度和叶绿素浓度的影响

利用高分辨率的海表面温度(SST)和叶绿素a浓度数据,分析2015年超强台风"彩虹"对粤西近岸海洋动力环境的影响。结果表明:"彩虹"过境后,粤西海域SST总变化为降温,且台风路径右侧降温高于左侧,最大热损失达到-9×10~6 J/m~3。"彩虹"引起的降温幅度以及最大降温出现时间在不同海区有所不同。珠江口附近海域、珠江口外海200 m等深线附近以及阳江至东海岛沿岸区域在台风登陆后2―4 d形成3个降温中心,最大降温均为-2℃左右。对台风路径两侧近岸、陆架和深水六个区域对比分析发现,近岸SST变化幅度最大,且两侧最大降温时间相同,而陆架和深水区则是左侧降温低于右侧。台风路径左侧雷州半岛以东约100 km和海南岛以东近海的叶绿素a浓度显著增加,最大增幅达5 mg/m~3。     

上层海洋对热带风暴“天鹰”的响应

根据2005年7、8月份锚系温盐和海流观测资料并结合卫星遥感数据,重点关注海南岛东南侧热带风暴影响区域,研究了2005年第8号热带风暴"天鹰"引起的上层海水降温机制,分析结果表明:热带风暴过境期间,海表面有着显著的降温,且台风路径右侧海表温度下降的幅值和范围要远大于左侧;观测点处,海表温度下降2~4℃,混合层加深10~20 m,海洋热容量变化为-10~-20 k J·cm~(-2),上升流及垂向夹卷对于海洋热容量的变化有着最重要的作用,是导致海表温度下降的主要原因。而在海表温度降低过程中,通过比较发现,垂向的夹卷相较于上升流又占据着主导作用。     

温度、光照对小环藻生长和叶绿素a含量的影响

用单因子和正交实验方法研究了温度和光照对小环藻生长和叶绿素a含量的影响。结果表明,温度对小环藻生长和叶绿素a含量有极显著影响(P<0.01),当温度在30~40℃时比增长率和叶绿素a含量分别为0.37~0.38 d-1和1 084.4~1 214.2μg.L-1,均显著高于其他温度组。光照对小环藻生长和叶绿素a含量有极显著影响(P<0.01),当光照强度从29.25~146.26μmol.m-2.s-1时比增长率最高,为0.30~0.32 d-1;而叶绿素a含量则在9.75~58.50μmol.m-2.s-1时最高,达709.7~731.8μg.L-1,极显著高于其他照度组。正交实验结果表明:在35℃、87.75μmol.m-2.s-1条件下种群增长最快,比增长率为0.4402 d-1;在30℃、29.25μmol.m-2.s-1时,叶绿素a含量最高,为1 746.6μg.L-1。     

基于遥感水质的夏季东海鲐鱼渔情预报研究

根据2007~2009年7~9月渔汛期间我国鲐鱼灯光围网在东海的生产数据,利用海表温、叶绿素浓度、悬浮物浓度和透明度等遥感水质数据,分别将作业网次比例和单网次产量(CPUE)作为适应性指数,利用算术平均数(AM)和几何平均数(GM)分别建立基于海表温、叶绿素浓度、悬浮物浓度和透明度的综合栖息地指数模型。结果表明,AM栖息地指数模型和GM栖息地指数模型拟合效果较好(P<0.01),在HSI大于0.5的海域,2007~2009年7~9月平均作业网次比例在65%以上,各月平均CPUE均高于19.82 t/net。研究认为,AM模型稍优于GM模型。利用2010年7~9月生产数据及遥感水质数据对AM模型进行验证,分析认为,87%以上的作业网次和产量分布在HSI高于0.5的海域,CPUE为14~17 t/net,且较稳定,波动较小。研究认为,基于遥感水质数据的AM栖息地指数模型能较好地预测东海鲐鱼渔场。     

温度、盐度和照度对北方娄氏藻生长和叶绿素a含量的影响

通过单因子与正交实验研究不同温度、盐度和照度对北方娄氏藻(Lauderia borealis)生长和叶绿素a含量的影响。结果表明:不同温度、盐度和照度对北方娄氏藻的比增长率μ和叶绿素a含量影响有统计学意义(P0.05)。当温度为20~30℃,盐度为25~35,照度为2 500~3 500 lx时,北方娄氏藻比增长率较大,叶绿素a含量较高,适宜北方娄氏藻的生长。温度和盐度分别是影响北方娄氏藻生长速率和叶绿素a含量的最主要因素,温度25℃、盐度35、照度2 500~3 000 lx是北方娄氏藻生长的最优组合条件。     

季风影响下北部湾颗粒无机碳浓度时空变化特征

以北部湾1999年7月至2009年6月11年的Sea Wi FS卫星遥感颗粒无机碳度资料为基础,研究北部湾颗粒无机碳浓度的时空分布特征,并初步探讨其可能的海洋动力调控机制。结果表明:在季节变化上,整个冬季北部湾颗粒无机碳浓度普遍较高,表现出季节平均最大值(0.012 mol·m-3),春季普遍较低(0.004 mol·m-3),表现出全年最低水平;不同区域的最高水平出现的季节却有所不同:北部湾北部沿岸区域颗粒无机碳浓度在秋季较高,海南岛西部大部分海域在冬季较高,北部湾西北部沿岸则在夏季较高;在空间分布上,近岸海区的颗粒无机碳浓度明显高于海湾中央区域,北部湾北部海域普遍高于南部海域,东部海域高于西部海域。综合相关分析表明,北部湾颗粒无机碳浓度的这一时空分布特征主要同季风的强弱及风向有关,同时也可能与海表温度、流场(如沿岸上升流等)及陆地径流量等有关。     

珠江口海域营养盐和叶绿素a的时空分布特征

【目的】研究珠江口海域营养物和叶绿素a的时空分布特征。【方法】根据2015年5月(春季)、8月(夏季)和10月(秋季)3个季节的现场调查资料,通过对3个季节浮游植物Chl-a以及包括氮磷比在内的营养结构进行综合分析,深入探讨珠江口海域浮游植物Chl-a的时空变化调控机制。【结果】珠江口海域各季节营养盐呈高氮低磷分布,3个季节N︰P均值49.6。叶绿素a季节差异明显,夏季叶绿素a含量是春季的2倍、秋季的9倍。【结论】春季浮游植物生长受温度影响较大,夏、秋两季由于外海水的入侵导致磷限制比较显著;DIN能满足各季节浮游植物生长的需要,珠江口海域浮游植物生长对于磷营养盐的响应要优于氮营养盐。     

湛江港海域叶绿素a浓度的高光谱遥感反演

基于表观光学法研究冬季湛江港海域高光谱遥感叶绿素a浓度的反演模型构建,结果表明,该海域单波段遥感反射率与叶绿素a浓度相关性低,波段比值和遥感反射率的一阶微分法可提高叶绿素a浓度反演精度。665nm处的遥感反射率一阶微分值与叶绿素a浓度相关性良好,相关系数可达0.84。一阶微分相关系数大于0.8的波段大部分处于叶绿素a红光强烈吸收区域,对于富营养化的湛江港海域采用一阶微分方法构建叶绿素a浓度的遥感反演模型具有合理性。     

ENSO对南海北部初级生产力的影响

利用2002年7月至2014年12月的卫星遥感数据,研究ENSO期间我国南海北部的海表温度(SST)、风场等环境场变化特征,并探讨其对南海北部初级生产力的影响。结果表明,El Ni?o/La Ni?a期间南海北部初级生产力较正常年份变化显著,很大程度上受到ENSO的调控,其变化与风场、SST等的分布变化密切相关。具体趋势:厄尔尼诺年的冬季风期间,南海北部海域风场强度减小,沿岸海域SST升高,初级生产力降低,南海东北部海域SST降低,初级生产力升高,整个海域的总初级生产力与MEI指数呈负相关关系;拉尼娜年的冬季风期间,相应海域的风场、SST和初级生产力的变化则与厄尔尼诺期间的相反,整个海域的总初级生产力与MEI指数呈正相关关系。     

Numerical simulation of the genesis of typhoon Durian (2001) over the South China Sea: The effect of sea surface temperature

Typhoon Durian (2001),which formed over the South China Sea (SCS),was simulated by using the Weather Research and Forecasting (WRF) model. The genesis of typhoon Durian which formed in the monsoon trough was reproduced by numerical simulations. The simulated results agree reasonably well with observations. Two numerical experiments in which the sea surface temperature (SST) was either decreased or increased were performed to investigate the impact of the SST on the genesis of the ty-phoon. When the SST was decreased by 5℃ uniformly for all grids in the model,the winds calculated became divergent in the lower troposphere and convergent in the upper troposphere,creating conditions in which the amount of total latent heat release (TLHR) was low and the tropical cyclone (TC) could not be formed. This simulation shows the importance of the convergence in the lower tropo-sphere and the divergence in the upper troposphere for the genesis of the initial vortex. When the SST was increased by 1℃ uni-formly for all grids,a stronger typhoon was generated in the results with an increase of about 10 m s-1 in the maximum surface wind speed. Only minor differences in intensity were noted during the first 54 h in the simulation with the warmer SST,but apparent dif-ferences in intensity occurred after 54 h when the vortex began to strengthen to typhoon strength. This experiment shows that warmer SST will speed the strengthening from tropical storm strength to typhoon strength and increase the maximum intensity reached,while only minor impact can be seen during the earlier stage of genesis before the TC reaches the tropical storm strength. The results sug-gest that the amount of TLHR may be the dominant factor in determining the formation and the intensification of the TC.     

Numerical Simulation of Typhoon Muifa(2011) Using a Coupled Ocean-Atmosphere-Wave-Sediment Transport(COAWST) Modeling System

The newly developed Coupled Ocean-Atmosphere-Wave-Sediment Transport(COAWST) Modeling System is applied to investigate typhoon-ocean interactions in this study. The COAWST modeling system represents the state-of-the-art numerical simulation technique comprising several coupled models to study coastal and environmental processes. The modeling system is applied to simulate Typhoon Muifa(2011), which strengthened from a tropical storm to a super typhoon in the Northwestern Pacific, to explore the heat fluxes exchanged among the processes simulated using the atmosphere model WRF, ocean model ROMS and wave model SWAN. These three models adopted the same horizontal grid. Three numerical experiments with different coupling configurations are performed in order to investigate the impact of typhoon-ocean interaction on the intensity and ocean response to typhoon. The simulated typhoon tracks and intensities agree with observations. Comparisons of the simulated variables with available atmospheric and oceanic observations show the good performance of using the coupled modeling system for simulating the ocean and atmosphere processes during a typhoon event. The fully coupled simulation that includes a ocean model identifies a decreased SST as a result of the typhoon-forced entrainment. Typhoon intensity and wind speed are reduced due to the decrease of the sea surface temperature when using a coupled ocean model. The experiments with ocean coupled to atmosphere also results in decreased sea surface heat flux and air temperature. The heat flux decreases by about 29% compared to the WRF only case. The reduction of the energy induced by SST decreases, resulting in weakening of the typhoon. Coupling of the waves to the atmosphere and ocean model induces a slight increase of SST in the typhoon center area with the ocean-atmosphere interaction increased as a result of wave feedback to atmosphere.     

Movements of the Western Pacific Warm Pool Centroid and Their Relationship to Sea Surface Temperature Changes in Ni(n)o Regions

By using monthly historical sea surface temperature (SST) data for the years from 1950 to 2000, the Western Pacific Warm Pool (WPWP) climatology and anomalies are studied in this paper. The analysis of WPWP centroid (WPWPC) movement anomalies and the Nino-3 region SST anomalies( SSTA) seems to reveal a close, linear relation between the zonal WPWPC and Nino-3 region SSTA, which suggests that a 9' anomaly of the zonal displacement from the climatological position of the WPWPC corresponds to about a 1 ℃ anomaly in the Nino-3 region area-mean SST. This study connects the WPWPC zonal displacement with the Nino-3 SSTA, and it may be helpful in better understanding the fact that the WPWP eastward extension is conducive to the Nino-3 region SST increase during an El Nino-Southern Oscillation (ENSO) event.     

Impact of two typhoons on the marine environment in the Yellow Sea and East China Sea

This study investigated the ef fects of two typhoons(Nari and Wipha) on sea surface temperature(SST) and chlorophyll- a(Chl- a) concentration. Typhoons Nari and Wipha passed through the Yellow Sea on September 13, 2007 and the East China Sea(ECS) on September 16, 2007, respectively. The SST and Chl- a data were obtained from the Aqua/Terra MODIS and NOAA18, respectively, and the temperature and salinity in the southeast of the study area were observed in situ from Argo. The average SST within the study area dropped from 26.33°C on September 10 to a minimum of 22.79°C on September 16. Without the usual phenomenon of ‘right bias', the most striking response of SST was in the middle of the typhoons' tracks, near to coastal waters. Strong cooling of the upper layers of the water column was probably due to increased vertical mixing, discharge from the Changjiang River estuary, and heavy rainfall. During the typhoons, average Chl-a increased by 11.54% within the study area and by 21.69% in the off shore area near to the southeast ECS. From September 1 to 13, average Chl-a was only 0.10 mg/m~3 in the of fshore waters but it reached a peak of 0.17 mg/m~3 on September 18. This large increase in Chl-a concentration in of fshore waters might have been triggered by strong vertical mixing, upwelling induced by strong typhoons, and sedimentation and nutrient infl ux following heavy rainfall.     

西北太平洋柔鱼资源与海洋环境的GIS空间分析

本文根据1995～2001年的西北太平洋地区(35°N～45°N,140°E～170°W)巴特柔鱼资源调查与生产的实际情况对柔鱼渔获量进行了研究,并利用同期遥感反演的海洋表层温度数据(SST)和近表层叶绿素a数据(Chlorophylla),拓展了GIS的空间分析功能,定量地研究了我国远洋柔鱼产量与水温、叶绿素等海洋要素场之间的关系,揭示西北太平洋柔鱼中心渔场的环境特征,以期为我国西北太平洋海区的鱿鱼生产服务。     

一种湿地河流叶绿素a遥感反演方法

叶绿素a作为一项重要的水质安全评价指标,其浓度的准确监测对水产行业发展、水生态系统平衡和人类饮水安全等有着重要意义。随着对地观测卫星传感器空间和光谱分辨率的提高,遥感技术在河流水质时空变化监测中发挥着越来越重要的作用。本文以新疆巴音布鲁克湿地河流水体为研究对象,同步采集了水体反射光谱和水样,并在实验室对叶绿素a、浊度等水质参数进行测定。首先,基于光谱波段对叶绿素a浓度的敏感性分析,构建了多种光谱指数模型;然后,提出以4.50 mg/m³作为水体叶绿素a浓度分级阈值,利用三波段半分析模型因子D3B与叶绿素a的线性关系建立水体叶绿素a浓度分级标准,进而对比评估了11种经验、半分析模型分别在全部样本数据集和两级叶绿素a浓度数据集中的精度表现;其次,根据各模型精度结果选用三波段半分析模型D3B和蓝绿波段比模型OC₂V4,组成叶绿素a分级反演算法OC₂-D3B,其精度（R²=0.96,RMSE=0.32 mg/m³,MAE=0.24 mg/m³,MRE=5.71%）相比以上2种单一算法提高了50%以上;最后,本文利用Sentinel-2影像,对湿地河流水体叶绿素a浓度的空间分布特征和季节时序模式进行了分析,得到该水域夏季叶绿素a含量最高,春秋季次之,冬季最低的结论。此外,本研究还发现气温相比其他环境因子对水体Chl-a浓度的控制作用更加明显。     

Oxygen isotopic composition and its application to the study of tracing oceanographical process in Bering Sea and Chukchi Sea

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Comparison Between Early and Late 21~(st)C Phytoplankton Biomass and Dimethylsulfide Flux in the Subantarctic Southern Ocean

Time-series of chlorophyll-a(CHL),a proxy for phytoplankton biomass,and various satellite-derived climate indicators are compared in a region of the Subantarctic Southern Ocean(40°-60°S,110°-140°E)for years 2012-2014.CHL reached a minimum in winter(June)and a maximum in late summer(early February).Zonal mean CHL decreased towards the south.Mean sea surface temperature(SST)ranged between 8℃and 15℃and peaked in late February.CHL and SST were positively correlated from March to June,negatively correlated from July to September.CHL and wind speed(WIND)were negatively correlated with peak WIND occurred in winter.Wind direction(WIRD)was mostly in the southwest to westerly direction.The Antarctic Oscillation index(AAO)and CHL were negatively correlated(R=−0.58),indicating that as synoptic wind systems move southwards,CHL increases,and conversely when wind systems move northwards,CHL decreases.A genetic algorithm is used to calibrate the biogeochemical DMS model’s key parameters.Under 4×CO2(after year 2100)Regional mean SST increases 12%-17%,WIND increases 1.2ms−1,Cloud Cover increases 4.8%and mixed layer depth(MLD)decreases 48m.The annual CHL increases 6.3%.The annual mean DMS flux increase 25.2%,increases 37%from day 1 to day 280 and decrease 3%from day 288 to day 360.The general increase of DMS flux under 4×CO2 conditions indicates the Subantarctic regional climate would be affected by changes in the DMS flux,with the potential for a cooling effect in the austral summer and autumn.     

A Review of Interaction Between Neon Flying Squid (Ommastrephes bartramii) and Oceanographic Variability in the North Pacific Ocean

The neon flying squid(Ommastrephes bartramii) is a short-lived opportunistic species widely distributed in subtropical and temperate waters in the North Pacific Ocean. The life cycle of O. bartramii from planktonic eggs to nektonic adults is closely linked to oceanographic conditions. The fluctuations in O. bartramii abundance and distribution tend to increase and widen continuously due to the heavy influences of ocean-climate events on various spatio-temporal scales. In this study, we reviewed the interaction between O. bartramii and oceanography variability in the North Pacific with respect to large-scale climatic-oceanic phenomena including El Ni?o, La Ni?a, Kuroshio, Oyashio and Pacific Decadal Oscillation(PDO), as well as regional environmental variables such as sea surface temperature(SST), sea surface height(SSH), sea surface salinity(SSS), chlorophyll-a(Chl-a) concentration, and plankton density. The population dynamics of O. bartramii is mediated mainly by meso- and large-scale climatic-oceanic events(e.g., Kuroshio and Oyashio Currents) rather than other local environmental conditions(e.g., SST and Chl-a concentration), because all of the oceanographic influences are imposed on the context of large-scale climate changes(e.g., PDO). An unstructured-grid finitevolume coastal ocean model coupled with an individual-based model is proposed to simulate relevant physical-biological oceanographic processes for identifying ocean-climate influence and predicting O. bartramii distribution and abundance in the North Pacific. Future research needs to be focused on improving the knowledge about early life history of O. bartramii and evaluating the relationship between marine physical environment and two separate passive drifting life stages of O. bartramii including free-floating eggs and planktonic paralarvae.