The estimated spatiotemporal characteristics of particulate matter in the ocean vary with the measurement method used. This variation introduces considerable uncertainty in our understanding of how particle scattering cross-section, particle size, and carbon content relate to one another at local, regional, and global scales. A more accurate and detailed characterization of the spatiotemporal variations of particles in the water column and of the contribution of different types of particles to the optical parameters of water are crucial for improving our understanding of the marine biogeochemical cycle. In this study, we investigated how composition, size, and particulate organic carbon (POC) content of particulate matter, along with their corresponding optical proxies, change in the upper 200 m of an oligotrophic region in the tropical Western Pacific Ocean. We estimated the contributions of various water components to the particle backscattering coefficient and to POC. Using newly collected, vertically resolved data, we derived depth-resolved net primary productivity (NPP) with the absorption-based production model (AbPM) and the carbon-based production model (CbPM); both models account for vertical variations in water column properties. Our results indicated that particles larger than 8 & micro;m (especially minerals and aggregates) accounted for an increasing amount of POC at depths greater than 100 m, with a maximum at 500 m. In contrast, chlorophyll content decreased steadily with depth. Our comparison of the backscatter and absorption coefficients (optical proxies of POC) had the same trend, although the specific components that contributed to POC were different. Changes in parameters such as particle composition, size, POC content, and their optical proxies all corresponded to changes in the deep chlorophyll maximum (DCM) along the latitudinal gradient. When we compared the NPP estimates from the two approaches, the CbPM yielded higher values than the AbPM in surface waters, likely because of the way particles are distributed vertically. In areas where the DCM was deeper, the AbPM provided a better accounting of how individual components contributed to the NPP. Together, these findings clarify how particle composition and its vertical variability influence POC and inherent optical properties (IOPs) in this oligotrophic region. They also offer a basis for interpreting water column characteristics and assessing how changes in NPP may affect biogeochemical processes.

The Water and Sediment Regulation Scheme (WSRS), implemented since 2002, has been essential for controlling water flow and mitigating sediment siltation in the lower Yellow River. However, WSRS was suspended for the first time in 2016 and 2017 due to extremely low water flow. The rapid floodwater discharge over roughly 20 days conducted by WSRS strongly impacts total suspended solids (TSS) distribution in the Yellow River Estuary (YRE). This study employs high-frequency Sentinel-3 OLCI satellite imagery to investigate intraday TSS variations in the YRE under new water-sediment regulation conditions from 2016 to 2023. TSS concentrations were generally low during the 2016 and 2017 flood seasons, but increased markedly after WSRS resumed in 2018. Peak TSS values occurred in July or August, sometimes extending into September and October during autumn floods. A moderately strong positive correlation was observed between TSS concentrations at the river mouth and sediment load at Lijin Station during the flood seasons. The 2018 WSRS event generated an extensive river plume, with average TSS concentrations at the river mouth exceeding 400 g·m−3. From 2018 to 2023, TSS concentrations exhibited a declining trend during flood seasons, attributed to reduced sediment discharge and ongoing sediment accretion in the Yellow River Delta. Our findings highlight Sentinel-3 OLCI as a powerful tool to resolve WSRS-driven sediment dynamics, offering critical guidance for estuarine management.

The Yellow River Delta (YRD), one of the world’s significant river deltas, undergoes substantial surface transformations driven by a variety of factors. This study integrates optical and Synthetic Aperture Radar imagery, geophysical models, and hydrogeological data to analyze the spatiotemporal patterns, evolutionary characteristics, and mechanisms of surface change in the YRD’s coastal zones. Using Small Baseline Subset Interferometric Synthetic Aperture Radar techniques and Random Forest algorithms, the study examines surface deformation and land use/land cover transformations over the past 20 years. Areas with significant subsidence, especially in coastal regions, show annual rates of up to 20 cm. Anthropogenic landscapes in the YRD have expanded from inland to coastal areas, with notable growth in land cover types such as wetlands, forests, halophytes, aquaculture ponds, and salt fields. Quantitative spatiotemporal analysis shows that human activities, particularly brine extraction in salt fields, are major drivers of surface subsidence. The study’s optimized contraction source model, with a maximum vertical contraction of 18 cm/yr, provides a quantitative evaluation of subsidence mechanisms and brine aquifer changes. In conclusion, this research offers novel insights into the spatiotemporal dynamics and evolution of surface changes in major river deltas, presenting new perspectives and empirical evidence on the mechanisms driving subsidence in coastal zones.

The world is experiencing an increase in the frequency and intensity of extreme weather events, yet the influences of remote inland extreme weather events on the coastal ecosystem thousands of kilometers away remain poorly understood. Here we tracked the chain ecological effects of an extreme rainfall event in North China from terrestrial rivers to coastal aquaculture area of the eastern Shandong Peninsula. Our data suggest the autumn flood resulted from extreme rainfall event leads to abnormally low turbidity in the North Shandong Coastal Currents and coastal red tide blooms by introducing anomalous freshwater with an exceptionally high nitrogen-to-phosphorus ratio into the Bohai Sea. Lower salinity, stronger light conditions caused by limpid coastal currents, and phosphorus limitation resulting from red tide blooms account for huge kelp loss offshore of the eastern Shandong Peninsula. This study underscores the importance of considering multidisciplinary observation for risk management of unexpected extreme weather events. An extreme rainfall event in September 2021 in northern China caused cascading ecological effects that led to unusually low turbidity, red tide blooms, and subsequent kelp mortality events offshore of the eastern Shandong Peninsula, according to field and satellite data.

The hydrodynamic environment of the Changjiang (Yangtze River) Estuary and its adjacent sea area frequently experiences the influence of typhoon activities during the summer season. However, the differences in responses to typhoons with different trajectories are still poorly understood. Using buoy observations with synchronous satellite images, we investigated the sediment dynamics response to Typhoon Danas and Lekima, which passed through the Changjiang Estuary and its adjacent sea area from the east and west sides, respectively. The results indicated that wind forcings disrupted the semidiurnal cycles of ocean currents, leading to southeastward or northwestward residual currents during typhoons Danas and Lekima, respectively. The residual current velocity was typically below 150 mm/s under calm conditions but exceeded 200 mm/s, reaching up to 600 mm/s during typhoon conditions. Typhoon Danas (Lekima) generated onshore (offshore) Ekman transport in the surface layer, resulting in coastal downwelling (upwelling) and bottom offshore (onshore) currents due to the Ekman pumping (suction) effect. Typhoon Danas shifted the Changjiang Diluted Water from northeastward to southeastward, triggering the post-typhoon phytoplankton bloom, while Typhoon Lekima strengthened and even drove the detachment of the Changjiang Diluted Water. These findings suggest the need for different preventive strategies based on the trajectory of each typhoon, considering the potential land damage caused by west-side typhoons and the occurrence of post-typhoon Harmful Algal Blooms resulting from east-side typhoons. Additionally, sediment transport primarily occurred in the bottom layer, governed by the combined effect of tidal currents and typhoon-driven bottom currents. Typhoon Danas, located on the east side of the Changjiang Estuary, led to offshore (positive cross-shore) sediment flux and southwestward (negative along-shore) sediment flux. Conversely, Typhoon Lekima, situated on the west side, caused onshore (negative cross-shore) sediment flux and northeastward (positive along-shore) sediment flux. These findings suggest that existing sediment records may underestimate the frequency and intensity of historical typhoon activities.

In the past decade, the synthetic aperture radar interferometry (InSAR) technique has been extensively employed in deltas, making it possible to obtain more subsidence signals. However, the spatiotemporal nonlinearity of land subsidence often results in inaccurate estimations. Based on 72 Sentinel-1A images captured from 2016 to 2021 and the time-series persistent scatterer-interferometric SAR (PS-InSAR) method, we comprehensively analyze the temporal and spatial dynamics of recent land subsidence in the Yellow River Delta (YRD). The findings suggest a notable spatial shift in the subsidence funnel area within this delta region over the past 6 years (2016-2021), with gradual westward movement from the salt fields in the northeast to those in the central north. Additionally, with 2020 as the demarcation point, there was a notable change in magnitude, initially exhibiting acceleration at -333 mm/yr, followed by deceleration at -231 mm/yr and culminating in renewed acceleration at -413 mm/yr. The subsidence characteristics may be attributed to changes in the underground brine reserves, leading to consolidation of the confined aquifer. Furthermore, the ground subsidence trend suddenly slowed at the end of 2019, which we speculate is related to the significant reduction in human activities caused by COVID-19 prevention and control measures.

It is important to determine the relationship between the concentration of chlorophyll a (Chla) and the inherent optical properties (IOPs) of ocean water to develop optical models and algorithms that characterize the biogeochemical properties and estimate biological pumping and carbon flux in this environment. However, previous studies reported relatively large variations in the particulate backscattering coefficient (bbp(λ)) and Chla from more eutrophic high-latitude waters to clear oligotrophic waters, especially in oligotrophic oceanic areas where these two variables have little covariation. In this study, we examined the variability of bbp(λ) and Chla in the euphotic layer in oligotrophic areas of the tropical Western Pacific Ocean and determined the sources of these variations by reassessment of in-situ measurements and the biogeochemical-argo (BGC-Argo) database. Our findings identified covariation of bbp(λ) and Chla in the water column below the deep Chla maximum (DCM) layer, and indicated that there was no significant correlation relationship between bbp(λ) and Chla in the upper layer of the DCM. Particles smaller than 3.2 µm that were in the water column above the DCM layer had a large effect on the bbp(λ) in the vertical profile, but particles larger than 3.2 µm and smaller than 10 µm had the largest effect on the bbp(λ) in the water column below the DCM layer. The contribution of non-algal particles (NAPs) to backscattering is up to 50%, which occurs in the water depth of 50 m and not consistent with the distribution of Chla. Phytoplankton and NAPs were modeled as coated spheres and homogeneous spherical particles to simulate the bbp(λ) of the vertical profile by Aden-Kerker method and Mie theory, and the results also indicated that the backscattering caused by particles less than 20 µm were closer to the measured data when they were below and above the DCM layer, respectively. This relationship also reflects the bbp(λ) of particles in the upper water was significantly affected particle size, but bbp(λ) in the lower water was significantly affected by Chla concentration. This effect may have relationship with phytoplankton photoacclimation and the relationship of a phytoplankton biomass maximum with particle size distribution in the water column according to the previous relevant studies. These characteristics also had spatial and seasonal variations due to changes of Chla concentration at the surface and at different depths. There was mostly a linear relationship between Chla and bbp(700) during winter. During other seasons, the relationship between these two variables was better characterized by a power function (or a logarithmic function) in the lower layer of the DCM. The spatial and vertical relationships between the bbp(λ) and Chla and the corresponding variations in the types of particles described in this study provide parameters that can be used for accurate estimation of regional geochemical processes.

There is a vast upwelling area induced by the southeast monsoon in the waters off South Java, making the region an important fishing ground. Climate events can affect the variation of upwelling, but oceanographers have different understandings on the extent to which climate events control upwelling in this area, which leads to a lack of basis for studies on the evaluation and mechanisms of the variability of fishery resources in the region. The correlation between environmental parameters, including surface temperature (SST), chlorophyll-a (Chl-a) concentration, and climate event indices in South Java from 2003 to 2020 was analyzed. Results show that the Indian Ocean Dipole (IOD) has a greater influence on the interannual variability of upwelling intensity than ENSO. During the IOD, variations in equatorial latitudinal winds excite different types of Kelvin waves that anomalously deepen or shallow the thermocline, which is the main cause of anomalous variations in upwelling, independent of variations in the local wind field. A correlation between the interannual variability in upwelling and the annual catches was revealed, showing that climatic events indirectly affect fishery resources through upwelling effects. During positive IOD/El Niño periods, strong upwelling delivers more nutrients to the surface layer, which favors fish growth and reproduction, resulting in higher annual catches. A negative IOD/La Niña, on the other hand, leads to weaker upwelling and fewer nutrients into the surface waters. Fish tend to move in deeper waters, making traditional fishing methods less efficient and consequently lower annual catches.

In recent years, noticeable subsidence depressions have occurred along the coastal zone of the Yellow River Delta. In some coastal areas, the average annual subsidence varies from tens of millimeters to hundreds of millimeters. Although some studies have discovered a significant land subsidence funnel in the coastal zone of the Yellow River Delta, it has rarely been reported in recent years. Using Sentinel-1A/1B images from the last five years and permanent scatterers interferometric synthetic aperture radar technology, we found a typical subsidence bowl in the northeastern part of the delta, with a cumulative settlement of nearly 1 m over five years. In addition, we used the approach of soil mechanics to simulate the settlement of confined brine layers with different thicknesses under drainage conditions. We found that the 15 m thick confined aquifer can produce 1 m of settlement for every 15% decrease in water content. The simulation results explain the large settlement of the brine industrial area. This study can provide guidance for brine mining in the future. If we continue to overexploit underground brine, there will be more severe land subsidence in the delta in the future.

This is a dataset for 'An inland extreme rainfall event triggered unexpected coastal ecological disasters thousands of kilometers away'

近岸高浊度二类水体具有复杂的海洋光学特性,不同影像源反射率产品在该类水体的适用性尚待充分论证.以黄河口水体为典型研究对象,以适用于黄河口的ACOLITE DSF算法校正的Landsat离水反射率产品为参考,通过星星匹配,对基于不同大气校正算法的Sentinel-2-MSI(S2-MSI)和Sentinel-3-OLCI(S3-OLCI)离水反射率产品在黄河口的适用性进行了评估.结果表明,在黄河口高浑浊-极度浑浊水体,iCOR算法校正的S2-MSI和S3-OLCI的离水反射率产品与参考产品的一致性高于其他算法,其次为FLAASH和Sen2Cor算法,C2RCC算法表现相对较差.iCOR、FLAASH和Sen2Cor算法除在高浑浊水体的近红外波段平均百分比相对误差EMARD超过34％外,在绿、红波段的EMARD均小于24％,Sen2Cor算法结果整体上与FLAASH的相似.iCOR、FLAASH和Sen2Cor算法随着水体浑浊程度增加,误差越小;而C2RCC算法则随着水体浑浊程度的增加,误差越大,且整体存在低估.研究结果可为高浊度二类水体大气校正的选择提供有效借鉴,并为黄河口悬沙高分辨率动态监测打下基础.

The structure and composition of plagioclase in volcanic rocks provide important information regarding magmatic evolution.In this study,we systematically analyzed the mineralogy of plagioclase phenocrysts in lavas from the East Rift(ER),Manus Basin.Results show that the plagioclase phenocrysts in basaltic andesites have normal zoning,the An values for the core-mantle(An=80-87)of plagioclase belong to high-An plagioclase,and the An values decrease sharply for the rim.In dacites,the composition of plagioclase phenocrysts slightly changes from the core to the rim,most plagioclases have normal zoning with the An value decreasing gradually,and few plagio-clases have oscillatory zoning.The calculation results of crystallizing temperature and pressure for phenocrysts show that the magma evolution process in ER involved the following phenomena:1)Magma originated via partial melting of the mantle at～1300℃;2)In the early age,magma had a high ascend rate owing to the large magma sup-ply.3)After a small degree of fractional crystallization,magma eventually ejected at a high velocity and tempera-ture and formed basalt-basaltic andesites.In the late stage of the ER lavas,the magma underwent strong fractional crystallization owing to the low supply rate of magma and long stay of magma in the chamber(3-10 km;960℃-1020℃)and finally formed acidic lavas.Moreover,we argue that magma mixing did not play an important role in the magmatic evolution process.

To investigate patterns of horizontal atmospheric latent energy (LE) transport toward the Arctic, we applied the Self-Organizing Maps (SOM) method to the daily vertically integrated horizontal LE flux from ERA5 Reanalysis in winter (January to March) during 1979–2021. A clear picture depicting the LE transport to the Arctic at a synoptic scale then emerged, with four primary transport pathways identified: The Northern Europe, the Davis Strait, the Greenland Sea, and the Bering Strait pathways. The four primary pathways occurred at a comparable frequency, and noticeable interannual variability was observed in their time series of frequency during 1979–2021. Further analysis suggested that the northward LE transport through all these pathways is significantly modulated by cyclones, with the Northern Europe and the Greenland Sea pathways being mostly affected. Generally, more frequent and stronger cyclones were observed near the entry regions of LE transport compared to other regions. Moreover, this study provides a comprehensive picture of how atmospheric LE transport is related to air temperature, moisture, surface heat flux, and sea ice anomalies over the Arctic Ocean in winter. Through a thermodynamic perspective, we argue that the deleterious impacts of poleward LE transport on Arctic sea ice are to a large extent attributable to the enhanced local atmosphere-ice interactions, which increase downward longwave radiation (DLR) plus turbulent fluxes, consequently warming the surface and promoting the loss of sea ice. According to the quantitative results, among the four primary pathways, LE transport through the Davis Strait and the Greenland Sea could cause the loss of Arctic sea ice most efficiently.

浒苔的暴发会对水体生态环境产生巨大的影响,对此进行遥感监测具有十分重要的意义.本文基于现场同步实测的有色溶解有机物(colored dissolved organic matter,CDOM)吸收系数、叶绿素浓度以及光谱数据建立遥感反演模型,再结合 MODIS 卫星影像提取山东半岛南侧近岸海域在各年份浒苔暴发前后 CDOM 与叶绿素浓度的时空分布特征.结果表明,浒苔的消亡分解会在水体中产生大量的CDOM,但浒苔的生长繁殖同样会消耗CDOM,此外CDOM还受到浒苔暴发时期强烈的光降解作用.在各种因素的综合作用下,研究区海域CDOM浓度在浒苔暴发时期微弱升高,浒苔消亡后CDOM浓度则开始回落.浒苔在暴发期会抑制其他浮游微藻的生长,使研究区海域叶绿素浓度有所降低,而浒苔消亡后叶绿素浓度有所上升.水体中的叶绿素受多种生物地球化学因素的影响,因此叶绿素浓度的降低与浒苔的暴发强度之间没有明确的相关性.遥感反演可以大范围快速地提取水体中各种要素的分布情况,但就浒苔的暴发对海水中各要素的影响机制而言,还需要结合各种生态环境因子进行综合分析.

A super El Niño event occurred in the equatorial Pacific during 2015–2016, accompanied by considerable regional eco-hydro-climatic variations within the Mindanao Dome (MD) upwelling system in the tropical western Pacific. Using timeseries of various oceanic data from 2013 to 2017, the variability of eco-hydro-climatic conditions response to the 2015/2016 super El Niño in the upper 300 m of the MD region are analyzed in this paper. Results showed that during the 2015/2016 super El Niño event, the upwelling in the MD region was greatly enhanced compared to those before and after this El Niño event. Upwelling Rossby waves and the massive loss of surface water in the western Pacific were suggested to be the main reasons for this enhanced upwelling. Decreased precipitation caused by changes in large-scale air-sea interaction led to the increased surface salinities. Changes in the structures of the thermohaline and nutrient distribution in deep waters contributed to the increased surface chlorophyll a , suggesting a positive effect of El Niño on surface carbon storage in the MD region. Based on the above analysis, the synopsis mechanism illustrating the eco-hydro-climatic changing processes over the MD upwelling system responding to the El Niño event was proposed. It highlights the prospect for the role played by El Niño in local eco-hydro-climatic effects, which has further profound implications for understanding the influence of the global climate changes on the ocean carbon cycle.

To study the effect of mineralogical assemblages and chemical characteristics of clays mineral particles on absorption properties in coastal waters of China, we designed a tank experiment and measured the optical properties of suspensions of clay mineral particles for samples collected in Yellow River Estuary (YRE), Changjiang River Estuary (CRE) and Pearl River Estuary (PRE). We designed eight kinds of suspensions of clay mineral particles with concentration of 5, 10, 20, 30, 40, 50, 100 and 200mg/L. The absorption coefficient was measured for all the samples. The results show that the mass-specific absorption coefficient of clay mineral particles (am*) varies for samples collected respectively in YRE, CRE and PRE. The magnitude of am* is higher for samples collected in PRE compared with samples collected in YRE and CRE, especially in the blue band, with am*(410) for the sample collected in PRE 1.5 times higher than that collected in YRE and CRE. We discovered that the composition of clay mineral in PRE is obviously different from that in YRE and CRE. In addition, the content of iron element is higher for samples collected in PRE than that collected in YRE and CRE. The difference in the composition of clay mineral and higher content of iron element could be the reason that the magnitude of am* is significant different for the samples collected in PRE than that collected in YRE and CRE. It suggests that the absorption coefficient of clay mineral particles suspended in waters is not only connected to the SPM concentration, but also mineral and element composition, such as iron. Although the composition of clay mineral and concentration of iron could explain only part of variability observed in the absorption coefficient of clay mineral particles, it is of significant importance for further discover the inherent optical properties in coastal waters and can be helpful for improving the algorithm accuracy in ocean color remote sensing.

Seamounts affect the surrounding physical oceanography and form unique dynamic processes. The influences of these processes on biological and sedimentary distributions are quite different in seamount areas at different depths. The Y3 seamount is located in the Yap Arc of the tropical Western Pacific Ocean. The water depth of its summit is ∼280 m. Based on field data obtained in December 2014 and other open-access data, the physical oceanography around the Y3 seamount was preliminarily analyzed. The results show that the upper layer (0–150 m) was under the influence of the westward-flowing North Equatorial Current (NEC), while the eastward-flowing North Equatorial Undercurrent (NEUC) controlled the water between 200–800 m. The NEC was strong and steady, but the NEUC was disturbed by the Y3 seamount. The cold dome above the Y3 seamount was not caused by a Taylor cap or tidal rectification but probably by upwelling during the survey time. Tidal currents were squeezed against topography and greatly amplified in the Y3 seamount. The thicknesses of the surface turbulent layers were greatly influenced by the spring-neap tidal cycle. The turbulent diffusivities in the sea surface layer above the Y3 seamount were much larger than those in the open ocean. Calculations showed that the surface wind stress greatly affected the turbulent mixing in the surface layer of the Y3 seamount. The reciprocal action between the amplified tidal currents and topography was the most likely cause of the turbulent mixing near the bottom of the Y3 seamount. This study can provide a scientific basis for further study of biological and depositional characteristics at the Y3 seamount.

The quasi-synchronous ship-based multi-station hydrological investigation is the most basic and classic oceanographic research method. Nevertheless, the temporal variability of regional hydrological parameters raises the uncertainty of interpreting quasi-synchronous multi-station datasets. There has been a lack of in-depth assessment of the accuracy of survey results. In this study, two hydrological investigations during the summer of 2016 and winter of 2017 in the North Yellow Sea (NYS), accompanied by time series buoy observations, are presented to elucidate its influencing factors and applicability evaluation of cruise hydrological investigation data. The results indicate that the solar radiation and tidal condition account for the diurnal and semi-diurnal cycle of sea surface temperature (SST) in the summer and winter seasons, respectively. The sea surface salinity shows no significant variation during the cruise survey period, while the seasonal characteristic is dominated by the regional ocean circulation. The vertical hydrological structures (stratified in summer or well-mixed in winter) limit or enhance the upward diffusion of bottom resuspended sediment in the offshore area, furtherly causing higher surface turbidity in winter. The upwelling phenomenon is underestimated in summer cruises due to the diurnal variation of SST, while the cold-water tongue may be overinterpreted in winter cruise because of the northerly wind event. The applicability of multi-station hydrological investigation data depends on the comparison of the spatio-temporal scale of the scientific question being studied with the time-varying of the data. The coefficient of variation (CV) of sea surface parameters ranges from 0.03 to 0.36 for SST, 0.02 to 0.04 for SSS, 0.01 to 1.37 for chl a, and 0.06 to 0.50 for Rrs_555. The sea surface parameters display higher variabilities during spring and autumn season than summer and winter season over NYS, and the coastal areas show larger temporal variation than central NYS. It is suggested that the multi-station investigation should be conducted at the time when the hydrological structure is relatively stable as far as possible, especially for the nearshore stations. This study provides a meaningful reference for oceanographic research that although the background hydrologic field can be well described through the ship-based investigation data, attention should also be paid to the influence of time-varying meteorological and hydrological conditions to achieve more objective data interpretation.

In this study, a regional linear Markov model is developed to assess seasonal sea ice predictability in the Pacific-Arctic sector. Unlike an earlier pan-Arctic Markov model that was developed with one set of variables for all seasons, the regional model consists of four seasonal modules with different sets of predictor variables, accommodating seasonally varying driving processes. A series of sensitivity tests are performed to evaluate the predictive skill in cross-validated experiments and to determine the best model configuration for each season. The prediction skill, as measured by the sea ice concentration (SIC) anomaly correlation coefficient (ACC) between predictions and observations, increased by 32 % in the Bering Sea and 18 % in the Sea of Okhotsk relative to the pan-Arctic model. The regional Markov model's skill is also superior to the skill of an anomaly persistence forecast. SIC trends significantly contribute to the model skill. However, the model retains skill for detrended sea ice extent predictions for up to 7-month lead times in the Bering Sea and the Sea of Okhotsk. We find that subsurface ocean heat content (OHC) provides a crucial source of prediction skill in all seasons, especially in the cold season, and adding sea ice thickness (SIT) to the regional Markov model has a substantial contribution to the prediction skill in the warm season but a negative contribution in the cold season. The regional model can also capture the seasonal reemergence of predictability, which is missing in the pan-Arctic model.

综述了黄河三角洲地面沉降的研究现状、影响因素、沉降机理及造成的危害,并对减缓地面沉降的方法和海岸防护工程措施等方面进行了讨论.分析显示,受 自然和人为因素的影响,黄河三角洲的地面沉降具有显著的时空变异性.影响三角洲地区地面沉降的人为因素主要是地下水抽取和油气开采,但它们引起的地面沉降是区域性的;三角洲松散沉积物的固结压实是三角洲进积过程中地面沉降的主导因素,三角洲软土、黏性土的压缩延迟特征以及河道的频繁摆动致使三角洲的压实沉降过程的时空差异明显,但各个三角洲叶瓣体的平均沉降速率将随时间推移逐年递减.地面沉降将造成或加剧黄河三角洲及沿海地区的区域性洪水灾害、农田和水资源污染、土地排水难度、基础设施受损以及海岸侵蚀等环境问题,需制定有效的地下水资源保护和补救方案,修建防护堤坝等工程是当前行之有效的缓解措施.然而,沿海堤坝等工程建设引起的环境问题与其防护作用 目前还存在较大争议,因此,制定有效的海岸防护战略对于应对在海平面上升背景下的三角洲沉降引起的沿海地区环境灾害至关重要.