利用GNSS-R(全球导航卫星系统反射测量)技术进行准确的雪深监测已成为传统雪深测量的重要补充手段.本文使用GNSS-R技术反演了2012—2018年美国阿拉斯加州4个GPS观测站附近的雪深结果,结合加拿大气象中心(Canadian Meteorological Centre,CMC)提供的雪深模型数据产品,以PBO(Plate Boundary Observatory)H2O项目组提供的雪深资料为参考值,分析了不同手段获取的雪深值在不同时间尺度上的变化特征,同时评估了GNSS-R反演雪深结果作为独立数据集验证CMC模型数据的能力.结果表明:GNSS-R、CMC和PBO得到的长时间序列雪深结果均具有较为一致的明显周期性变化,整体上GNSS-R反演结果比CMC数据精度更高,更能反映雪深的年际变化情况.GNSS-R反演值和CMC模拟值均能够反映各测站PBO雪深值的逐月变化规律,但GNSS-R反演值的精度和稳定性总体上优于CMC模拟值.GNSS-R反演结果比CMC模拟值与PBO雪深值的季节性变化更具一致性,且对于本文研究的4个测站,GNSS-R反演雪深的精度和稳定性在雪深值较大的春季和冬季较高,雪深值较小的秋季略差.此外,本文还证实了GNSS-R反演的雪深结果可用于评估CMC模拟雪深值的精度,且评估效果在冬春季优于秋季.

Accurately building the relationship between the oceanographic environment and the distribution of neon flying squid（Ommastrephes bartramii） is very important to understand the potential habitat pattern of O. bartramii.However, when building the prediction model of O. bartramii with traditional oceanographic variables（e.g.,chlorophyll a concentration（Chl a） and sea surface temperature（SST）） from space-borne observations, part of the important spectrum characteristics of the oceanic surface could be masked by using the satellite data products directly. In this study, the neglected remote sensing information（i.e., spectral remote sensing reflectance（Rrs）and brightness temperature（BT）） is firstly incorporated to build the prediction model of catch per unit effort（CPUE） of O. bartramii from July to December during 2014–2018 in the Northwest Pacific Ocean. Results show that both the conventional oceanographic variables and the neglected remote sensing data are suitable for building the prediction model, whereas the overall root mean square error（RMSE） of the predicted CPUE of O.bartramii with the former is typically less accurate than that with the latter. Hence, the Rrs and BT could be a more suitable data source than the Chl a and SST to predict the distribution of O. bartramii, highlighting that the potential value of the neglected variables in understanding the habitat suitability of O. bartramii.

Using the quality-controlled radio occultation (RO) refractivity profiles from nine missions, this study extracts the planetary boundary layer height (PBLH) with the minimum refractivity gradient method during December 2006-November 2019 over the Arctic, investigates the spatiotemporal variations in the PBLH, and discusses the potential relationships of PBLH to sea ice concentration (SIC) and related atmospheric parameters. We find that the RO-derived Arctic PBLH is typically deeper in summer than in autumn, spring, and winter. Moreover, PBLH displays clearly synchronous seasonal cycle in all latitude zones over both land and ocean, whereas the PBLH seasonality in different latitude zones over ocean exhibits much different patterns to that over land. Significant increases in PBLH are typically detected in all latitude zones over the entire Arctic except for the 78 degrees N-84 degrees N over ocean. In general, PBLH over the Arctic Ocean is consistently negatively (positively) correlated with SIC [surface air temperature (SAT) and precipitable water vapor (PWV)] in each season. However, the response of PBLH to the variations in these parameters varies with the sea ice conditions. PBLH tends to be affected by the moisture advection and the surface radiative cooling in the open ocean and the solid ice pack, respectively, while the PBLH in the marginal ice zone typically has transitional features between the open ocean and the solid ice pack. Furthermore, variations in low cloud fraction (CF) appear to have no direct effect on PBLH over the Arctic Ocean.

悬浮泥沙质量浓度(SSC)是我国河口水体研究的重要水质参数之一,遥感测定SSC是一种重要的方法.为了研究遥感光谱数据和表层悬浮泥沙质量浓度(SSSC)之间的定量梯度关系,本文采集了长江口南汇嘴附近的表层沉积物,定量设计了SSSC的梯度变化值,利用ASD高光谱仪对不同质量浓度含沙水体进行了光学特性测量.结果表明,随着SSSC的增加,水体的光谱反射率曲线具有相似的形态,但也存在一定的差异.当SSSC<36.59 mg/L时,光谱曲线仅在560～580 nm之间有1个反射峰;当SSSC>52.69 mg/L时,光谱曲线第一反射峰位于570～710 nm,并在近红外波段780～820 nm处出现第二反射峰.光谱曲线第一峰值区间存在明显的"红移"现象,且波长的"红移"变化与SSSC的线性拟合R2达到0.91,说明两者呈较强的线性相关性.在400～900 nm光谱范围内,600～860 nm波段对0～200 mg/L范围内的SSSC变化较敏感且比较稳定,740～900 nm波段对>200 mg/L的SSSC的变化具有更强的响应能力.

基于监督式学习算法的BP神经网络模型,综合多源卫星遥感观测获取得到的海表面温度(sea surface temperature,SST)、叶绿素 a 质量浓度(chlorophyll-a mass concentration,Chl.a)、海表面高度距平值(sea surface height anomaly,SSHA)、海水质量变化和地转流等海洋环境因子,对西北太平洋柔鱼资源丰度的时空分布进行模拟和预测.以上海海洋大学中国远洋渔业数据中心2004-2017年的西北太平洋海域的柔鱼历史渔业捕捞数据为参考值,对基于多源卫星遥感观测的多海洋环境因子的柔鱼资源丰度的模拟和预测结果进行精度评定.结果表明:与仅采用SST、Chl.a和SSHA等进行柔鱼资源丰度时空分布预测的传统方案相比,进一步加入海水质量变化和地转流后,可有效提高利用BP神经网络对西北太平洋柔鱼资源丰度进行模拟和预测的精度:改进方法模拟的标准差(standard deviation,STD)和均方根误差(root mean square error,RMSE)均减少了 22％,且预测的STD减少了 31％,RMSE减少了 26％.

The Amazon Basin is the world's largest flowing basin and plays an important role in the global hydrological cycle. We combined 20 years of Gravity Recovery and Climate Experiment (GRACE), Swarm, and GRACE Follow-On (GRACE-FO) satellite data to investigate variations of the terrestrial water storage (TWS) from April 2002 to December 2021. We also analyzed the effects of precipitation, surface temperature, and evapotranspiration on TWS changes. Compared with different methods of processing GRACE data, we found that the combined filtering method of P4M6 + Gaussian 300 km in GRACE/GRACE-FO data provided the most accurate results. The long-term trend of TWS was an increase of approximately 0.23 +/- 0.11 cm/a in the Amazon Basin, and the central and eastern regions had the highest increase rate, whereas the southeastern region showed a decreasing trend. In the last 20 years, maximum TM variations occurred in April and minimum TWS variations occurred in October. In spring, the TWS in the Amazon Basin changes considerably from north to south (increasing in the north and decreasing in the south), opposite to that in winter. In the Amazon Basin, precipitation and surface temperature are the important factors affecting the TWS changes, unlike evapotranspiration. In October 2020, the anomalous decreases in TWS changes correlate with insufficient precipitation and rising surface temperatures, which results in a drought.

Sea ice conditions in the Canadian Arctic Archipelago (CAA) play a key role in the navigation of the Northwest Passage (NWP). Limited by observed sea ice thickness data, the research of temporal and spatial variation of sea ice in the NWP is insufficient. Based on the observed sea ice concentration and simulated thickness data, the temporal and spatial characteristics of sea ice concentration, extent and thickness from 1979 to 2017 in the NWP of the CAA were studied. The more specific pathways of the northern and southern routes of the NWP were evaluated. Against the background of the rapid retreat of Arctic sea ice, the 39-year observed sea ice concentration and extent of the NWP exhibited a relatively large decreasing trend in summer and fall, while heavy sea ice conditions were maintained in winter and spring, with slightly increasing trend in some subregions. The sea ice thickness in most subregions of the NWP showed a decreasing trend, with exception of Lancaster Sound. The sea ice thickness was larger along the northern route than the southern routes. The significant correlation (p < 0.05) between sea ice and surface air temperature (SAT) and sea surface temperature (SST) in the NWP suggested that the surface thermodynamic factors had a greater impact on sea ice in the summer and fall, and the variations of sea ice concentration were more closely correlated with the surface thermodynamic factors than sea ice thickness. The SST had a higher correlation with sea ice concentration than SAT, while SAT exhibited a higher correlation with sea ice thickness than SST. The remaining sea ice concentration and thickness in the fall, associated with the summer and fall SAT and SST, contributed to the formation of sea ice in the following winter and spring. The heat content and mixed layer depth were also be considered as the vertical thermodynamic factors to the sea ice condition in the NWP.

The throughflow in the Canadian Arctic Archipelago (CAA) had a significant impact on the North Atlantic Ocean with the Arctic climate change. The findings of physical mechanisms driving the throughflow in the CAA differed and few studies about the impact of sea level pressure (SLP) on the CAA throughflow were made. A high-resolution ice-ocean coupled Arctic Ocean Finite-Volume Community Ocean Model (AO-FVCOM) was used over the period 1978–2016 to examine the interannual and seasonal variability of the outflows in the CAA and the mechanism of SLP in driving the variation of the CAA throughflow quantitively. The simulated volume transport through Davis Strait, Nares Strait, Lancaster Sound and Jones Sound showed consistent increasing trends over 1978–2016 and the larger flux in winter and spring than in summer and fall. The variation of volume transport through Nares Strait contributed more than Lancaster and Jones Sound to the variation through Davis Strait. Five process-oriented experiments were made to further explore the role of SLP in setting up and controlling the sea surface height (SSH) difference and thus the throughflow transport in the CAA. The SLP was a primary forcing to control the SSH difference and the outflow transport compared with the wind forcing. The memory of the SSH to the SLP was short and an equilibrium state could be reached if the SLP varied with time. The upstream and downstream SLP difference, however, made a slight direct contribution to driving the volume transport of the CAA throughflow. In addition to the external forcing of SLP and wind, the variability of the CAA outflow was also influenced by the variability of the inflow/outflow and SSH on boundaries connected to the Pacific and Atlantic Oceans. The choice of SLP datasets from CORE-v2, ECMWF and NCEP was sensitive to the simulated uncertainty of volume transport.

As a key region of Northeast Passage, the polynya along the Siberian coast in the East Siberian and Chukchi Seas is important to local dynamic and thermodynamic processes, sea ice production and marine ecosystem. The detailed variations of polynya and the contributions of atmospheric and oceanic factors to the polynya have not been explored quantitatively. AMSR-E satellite data from January to April during the period 2003–2011 were used to study the impacts of wind stress and ocean heat transport on variations of polynya in the East Siberian Sea and Chukchi Sea. The study region was divided into six domains. Four sets of AMSR-E data with resolutions of 6.25 km and 12.5 km were compared based on two algorithms of sea ice concentration (referred to as 6.25 km-IC and 12.5 km-IC) and sea ice thickness (referred to as 6.25 km-h and 12.5 km-h). The monthly and yearly polynya areas in the four cases and six domains had remarkable differences. The two cases of 6.25 km-h and 12.5 km-h had larger areas of polynya than the other two cases of 6.25 km-IC and 12.5 km-IC. The difference in polynya area between the 6.25 km-h and 12.5 km-h cases was much smaller than the difference between the 6.25 km-IC and 12.5 km-IC cases. The study of atmospheric and oceanic mechanisms on polynya is influenced significantly by the sensitivity of polynya areas. In general, the impact of wind stress and ocean heat transport on the polynyas had noticeable monthly and interannual variations and was dependent on the locations of the polynyas. The alongshore and offshore wind had stronger correlations with the polynya area than ocean heat transport. Although the higher resolution (6.25 km) AMSR-E data are best for the study of atmospheric and oceanic impacts on polynya area, the coarse resolution (12.5 km) AMSR-E data based on sea ice thickness can also be used. Wind direction dominated the polynya area in the East Siberian Sea and wind speed dominated the polynya area in the Chukchi Sea. The variation in ocean heat transport was influenced mainly by variation in volume transport rather than variation in water temperature.

针对已有的GNSS-R反演潮位过程中由测站与潮位基准面高度的不确定性带来的误差,该文提出了一种 自适应测站高优化方法.该方法通过更新Lomb-Scargle谱分析噪声频率的阈值,可有效剔除噪声主频,从而提高GNSS-R反演潮位的精度.基于30 s采样间隔的GNSS的L2波段数据进行潮位反演的实验表明,该文提出的方法有效提高了GNSS-R反演潮位的精度.与传统反演方法相比,反演潮位与验潮站观测潮位之间的均方根误差降低了28.3％,相关系数提升了12.3％.同时,该文还证实了所提出方法求解出的自验潮站基准面起算的测站高度,可进一步应用于无验潮站或验潮站数据中断情况下的GNSS潮位反演.

Characteristics of temperature inversions (TIs) and specific humidity inversions (SHIs) and their relationships in three of the latest global reanalyses-the European Centre for Medium-Range Weather Forecasts Interim Reanalysis (ERA-I), the Japanese 55-year Reanalysis (JRA-55), and the ERA5-are assessed against in situ radiosonde (RS) measurements from two expeditions over the Arctic Ocean. All reanalyses tend to detect many fewer TI and SHI occurrences, together with much less common multiple TIs and SHIs per profile than are seen in the RS data in summer 2008, winter 2015, and spring 2015. The reanalyses generally depict well the relationships among TI characteristics seen in RS data, except for the TIs below 400 m in summer, as well as above 1000 m in summer and winter. The depth is simulated worst by the reanalyses among the SHI characteristics, which may result from its sensitivity to the uncertainties in specific humidity in the reanalyses. The strongest TI per profile in RS data exhibits more robust dependency on surface conditions than the strongest SHI per profile, and the former is better presented by the reanalyses than the latter. Furthermore, all reanalyses have difficulties simulating the relationships between TIs and SHIs, together with the correlations between the simultaneous inversions. The accuracy and vertical resolution in the reanalyses are both important to properly capture occurrence and characteristics of the Arctic inversions. In general, ERA5 performs better than ERA-I and JRA-55 in depicting the relationships among the TIs. However, the representation of SHIs is more challenging than TIs in all reanalyses over the Arctic Ocean.

结合海洋数学物理理论知识基础,运用matlab编程软件,在学生掌握了理论解法的基础上,利用计算机来实现理论问题的快速自动解法,使学生更好地理解所学的知识,并采用师生互动和同学之间相互讨论的形式,有效地将理论与实际相结合.

Knowledge of both the horizontal and vertical distributions of atmospheric water vapour is pivotal to understand the Earth's radiative balance. The Atmospheric Infrared Sounder (AIRS) provides an opportunity to monitor both precipitable water vapour (PWV) measurements and water vapour mixing ratio (MR) profiles. In this study, we incorporate a differential linear adjust model (DLAM) by using the European Centre for Medium-Range Weather Forecasts (ECMWF) Interim Reanalysis (ERA-Interim) to adjust the AIRS water vapour retrievals. The performance of the differential linear adjustment model (DLAM) is assessed by comparing AIRS water vapour retrievals with spatio-temporally synchronized radiosonde (RS) observations. Taking RS data as the reference, RMS of the DLAM-adjusted PWV is reduced by about 16%, and that of water vapour MR is decreased by 17% to 8% from 1000 to 500 hPa. We also find that the DLAM appears to be affected by the generally larger uncertainties of the a priori water vapour MR at upper tropospheric levels, and the DLAM-derived water vapour MR improvement is generally greater from 1000 to 850 hPa than 700 to 500 hPa. Moreover, the potential reason for the effectiveness of the DLAM on AIRS water vapour retrievals adjustment may be the deviation of the differential water vapour information derived by the differential process is significantly reduced in the incorporated model.

地下水储量是水资源管理和陆地表面过程与水循环研究的一个重要参数.然而,由于传统观测技术成本高和空间分辨率低等局限性,很难建立一个全球连续的综合地下水监测网,因此监测全球高时空分辨率的地下水储量及其变化仍是当前的一个挑战.2002年发射的低低卫—卫跟踪"重力恢复与气候试验"(GRACE)重力卫星为高分辨率地监测全球地下水储量及其变化,提供了一种新的可能手段.利用2002年8月～2011年2月的GRACE观测数据估计近10 a的月间隔全球陆地水总储存量,扣除了GLDAS水文模型(全球陆地数据同化系统)中的地表水、冰雪和生物水,得到全球地下水储量时间序列,并分析其季节性和长期变化及其特征.研究结果表明:GRACE探测到全球地下水储量具有明显的季节性变化,例如在南美洲的亚马逊河流域和亚洲中南部的周年振幅达到50 mm,而在澳大利亚南部和非洲北部的周年振幅只有10 mm左右.另外全球地下水储量具有明显的长期变化,如南美洲亚马逊河流域由于洪水造成地下水储量以6 mm/a的速率增加,拉普拉塔地区由于干旱造成地下水储量以7.5 mm/a的速率减少;中国新疆吐鲁番盆地地区的地下水储量以3.1 mm/a的速率减少,中国华北地区的地下水储量以4.8 mm/a的速率下降.

在我国创新创业的大环境下,大学创新的培养是非常重要的基础性教学工作.为了提高海洋测绘专业本科生的创新能力,针对交叉学科的特点,在教学实践中进行了探索与总结,在指导大学生创新方面有一定的借鉴意义.

Water vapor plays a vital role in the Arctic sea ice and climate change. The Atmospheric Infrared Sounder (AIRS) and the Moderate Resolution Imaging Spectroradiometer (MODIS) are useful tools for studying the water vapor variations over the entire Arctic. In this paper, we discuss precipitable water vapor (PWV) variations from the AIRS and MODIS Level-3 data products in response to Arctic sea ice change during December 2002-November 2016. The results indicate that both AIRS- and MODIS-derived PWV measurements tend to be underestimated, and this underestimation is generally greater for the latter than the former over both land and ocean. Additionally, both the AIRS and MODIS retrievals suggest that the atmospheres are drier in the solid sea ice pack and, to a lesser extent, in the marginal ice zone, than in the open ocean in each season. Moreover, statistically significant correlations between the PWV and sea ice concentration (SIC) anomalies are generally observed in all seasons under different ice conditions except in the open ocean, where variations in the PWV may be attributed to the poleward moisture transport from lower latitudes. The Arctic PWV and SIC variation patterns are also dominated by the atmospheric and ice conditions in the solid sea ice pack, respectively. The monthly mean PWV and SIC time series analysis further reveals that the Arctic PWV variations tend to be affected by a delayed effect of approximately 1.2-1.3 months from SIC changes from a climatological perspective.

2020年我国我国北斗卫星导航系统(BDS)即将实现全球运营,将会对美国全球定位系统(GPS)带来诸多冲击.因此,在上海海洋大学公共选修课程《GNSS发展与应用》的讲授过程中,需要实时更新GNSS发展与应用的相关讲授内容,以适应全球卫星导航系统(GNSS)的不断发展.本文探讨了一种基于课程视频教学的探讨方式,以期提高学生的学习兴趣与热情,提高教学效率.

培养文化水平高、思想道德先进、具备正确的世界观、人生观和价值观的人才是当代高等教育的根本任务.本文针对高校思政教育的现状进行分析后,从政策措施保障体系和具体实施等方面确保课程思政教学落到实处进行了探讨,可为从事高等教育的管理人员和课程教师提供参考.

面对上海海洋大学全校本科生的公共选修课程《GNSS发展与应用》至今已开设近三年,通过前期的教学总结和学生反馈,总结了存在的问题,并针对这些问题,探讨课程互动的教学方法,以期提高教学效率.

The air temperature is one of the most important parameters used for monitoring the Arctic climate change. The constellation observing system for meteorology, ionosphere, and climate and Formosa Satellite Mission 3 (COSMIC/FORMOSAT-3) radio occultation (RO) “wet” temperature product (i.e., “wetPrf”) is used to analyze the Arctic air temperature profiles at 925–200 hPa in 2007–2012. The “wet” temperatures are further compared with radiosonde (RS) observations. The results from the spatially and temporally synchronized RS and COSMIC observations show that their temperatures agree well with each other, especially at 400 hPa. Comparisons of seasonal temperatures and anomalies from the COSMIC and homogenized RS observations suggest that the limited number of COSMIC observations during the spatial matchup may be insufficient to describe the smallscale spatial structure of temperature variations. Furthermore, comparisons of the seasonal temperature anomalies from the RS and 5°×5° gridded COSMIC observations at 400 hPa during the sea ice minimum (SIM) of 2007 and 2012 are also made. The results reveal that similar Arctic temperature variation patterns can be obtained from both RS and COSMIC observations over the land area, while extra information can be further provided from the densely distributed COSMIC observations. Therefore, despite COSMIC observations being unsuitable to describe the Arctic temperatures in the lowest level, they provide a complementary data source to study the Arctic upper-air temperature variations and related climate change.