Annual and Seasonal Variations of the Sea Surface Heat Fluxes in the East Asian Marginal Seas     

Jungyul Na  Jangwon Seo  Heung-Jae Lie 《Journal of Oceanography》1999,55(2):257-270

Based on the twice-daily marine atmospheric variables which were derived mostly from the weather maps for 18 years period from 1978 to 1995, the surface heat flux over the East Asian marginal seas was calculated at 0.5°×0.5° grid points twice a day. The annual mean distribution of the net heat flux shows that the maximum heat loss occurs in the central part of the Yellow Sea, along the Kuroshio axis and along the west coast of the northern Japanese islands. The area off Vladivostok turned out to be a heat-losing region, however, on the average, the amount of heat loss is minimum over the study area and the estuary of the Yangtze River also appears as a region of the minimum heat loss. The seasonal variations of heat flux show that the period of heat gain is longest in the Yellow Sea, and the maximum heat gain occurs in June. The maximum heat loss occurs in January over the study area, except the Yellow Sea where the heat loss is maximum in December. The annual mean value of the net heat flux in the East/Japan Sea is −108 W/m² which is about twice the value of Hirose et al. (1996) or about 30% higher than Kato and Asai (1983). For the Yellow Sea, it is about −89 W/m² and it becomes −75 W/m² in the East China Sea. This increase in values of the net heat flux comes mostly from the turbulent fluxes which are strongly dependent on the wind speed, which fluctuates largely during the winter season. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

胜利海上油田分队计量研究     

周龙祥  孙月文 《海岸工程》1999,18(4):85-91

通过γ射线穿透油、气、水混合物后的透射和散射计数,经理论模拟计算,实现对原油含水率在线计量分析,测量含水率范围为３％－１００％,精度在２％以内。在实际应用过程中,运行稳定,易于操作,特别是修正了由于原油中含气地含水率测量带来的误差,技术和性能指标均已契过以往各种含水测量仪,通过应用,实现了海洋石油开发公司采油一、二分公司和油气集输大队的分队计量,使生产管理水平整体上了一个新台阶。  相似文献   

大亚湾养殖水域沉积物-海水界面营养盐扩散通量   总被引：16，自引：1，他引：15  

丘耀文  王肇鼎  高红莲  彭云辉 《热带海洋学报》1999,(3)

1998年5月10日和11日分别在大亚湾的大鹏澳和澳头养殖水域现场调查,分析了底层海水、上覆水、沉积物间隙水中营养盐的含量和磷的化学形态。结果表明：大亚湾养殖水域NH,HPO和H4SiO4含量从大至小为：间隙水,上覆水,底层海水;NO和NO含量变化不大。估算了沉积物一海水界面营养盐扩散通量,NH,NO,NO,HPO,H4SiO4平均通量分别为302．0,－0．06,－1．82,2．53,47．96μmol·（m2·d）－1。水体和沉积物中磷的主要化学形态分别为DOP（占TP的54％）和无机态（占总态的60％）。大亚湾养殖水域浮游生物生长由磷控制。沉积物间隙水中NO,NO,HPO,H4SiO4的浓度垂直分布变化不大,而NH的浓度垂直分布呈指数下降特征。  相似文献   

Numerical simulation of transport and dispersion of side-discharged sewage in tidal flow     

Liang Shuxiu  Shen Yongming  Sun Zhaochen  Ni Haoqing 《海洋学报(英文版)》2000,19(2):137-144

  相似文献   

渤海海冰特征厚度分析   总被引：8，自引：2，他引：6  

季顺迎  岳前进 《海洋学报》2000,22(6):117-123

通过海冰生消机理和数值试验,讨论了渤海海冰特征厚度的存在条件;对不同厚度的海冰表面温度、冰面热量收支、冰面下热传导和太阳辐射透射量进行了对比分析,分析了渤海海冰向特征冰厚的动态演化过程;在不同气温、风速、相对湿度和海洋热通量等气象和水文条件下,对渤海特征冰厚进行了计算;讨论了海冰生消的动态平衡过程,分析了1997/1998年冬季辽东湾JZ20-2海域实测冰厚与特征冰厚的相互关系。对渤海特征冰厚分析将有助于渤海海冰数值模拟工作的开展和对不同重现期设计冰厚的推算。  相似文献   

青藏高原春季土壤湿度异常与我国夏季降水的联系     

丁旭  赖欣  范广洲 《高原气象》2022,41(1):24-34

利用 197-2014年 GLDAS-CLM(Global Land Data Assimilation System-the Community Land Mod-el)地表参量数据集、中国区域逐日观测资料格点化数据集(CN05.1)和ERA-nterim大气环流再分析数据,研究青藏高原5月(春季)土壤湿度的异常变化...  相似文献   

青藏高原闪电活动的时空分布特征   总被引：11，自引：1，他引：10       下载免费PDF全文

郄秀书  袁铁  谢毅然  马耀明 《地球物理学报》2004,47(6):997-1002

利用卫星上携带的闪电探测仪所获取的8年闪电资料(1995～2002)对青藏高原闪电活动的时空分布以及高原季风期间闪电活动对地面热力学特征的响应进行了研究.结果表明,高原上的平均闪电密度为3fl·a-1·km-2,并在高原中部（32°N, 88°E）出现闪电密度峰值5.1fl·a-1·km-2.闪电活动主要发生在6～8月,并在6月下旬至7月中旬最为活跃.大部分地区的闪电活动日变化峰值出现在14:00～16:00 LT,在中西部的显著高山地区早于这一时刻,而在显著低海拔的塔里木和柴达木盆地晚于这一时刻.夏季季风期间高原上的闪电活动明显依赖于地表的热力学特征,并与地表鲍恩比和感热通量呈明显的线性正相关,相关系数分别为0.7和0.6,鲍恩比有可能作为调整闪电产生效率的量度.  相似文献   

随机森林算法在全球干旱评估中的应用   总被引：2，自引：0，他引：2  

方秀琴  郭晓萌  袁玲  杨露露  任立良  朱求安 《地球信息科学学报》2021,23(6):1040-1049

干旱是发生频率最高,造成社会、经济损失和生态破坏最严重、最广泛的自然灾害之一,因此对干旱进行可靠、有效的评估十分重要。本文以月平均降水、月平均温度、月最高温度、月最低温度、土壤湿度、蒸散发、NDVI、叶绿素荧光等作为解释变量,以基于SPI的干旱等级作为目标变量,采用随机森林算法,以2007—2012年的数据作为训练数据,以2013—2014年的数据作为预测数据,对全球11个气候区分别建立干旱等级评估模型。研究结论如下：SPI的时间尺度影响模型精度,在基于SPI1、SPI3、SPI6和SPI12划分的干旱等级的评估模型中,以基于SPI1的干旱等级为目标变量的模型的预测精度（60%~75%）较高,且模型能够捕捉到EM-DAT旱灾记录次数的90.91%、月份的78.47%,表明该模型对实际干旱事件具有良好的评估性能;干旱等级划分标准对模型的预测性能影响较小,可根据需求选择标准I（干旱/非干旱）或标准Ⅱ（重旱/非重旱）进行干旱评估;解释变量的相对重要性与SPI的时间尺度和气候差异等因素有关。降水对基于SPI1的干旱等级的重要性最大,随着SPI时间尺度的增加,降水的重要性逐渐减小,温度、土壤湿度、NDVI和ET的重要性逐渐增大。降水以外的其他变量在不同气候区的重要性不同。在热带气候区、亚寒带气候区和苔原气候区,温度或蒸散发的影响较大;在干燥气候区,土壤湿度的影响较大;在温带气候区,仍以降水的相对重要性最大;在湿润大陆性气候区,植被对干旱的影响较大。  相似文献   

Assimilating the LAI Data to the VEGAS Model Using the Local Ensemble Transform Kalman Filter: An Observing System Simulation Experiment          下载免费PDF全文

JIA Bing-Hao  Ning ZENG  XIE Zheng-Hui 《大气和海洋科学快报》2014,(4):314-319

Information on the spatial and temporal pat- terns of surface carbon flux is crucial to understanding of source/sink mechanisms and projection of future atmospheric CO2 concentrations and climate. This study presents the construction and implementation of a terrestrial carbon cycle data assimilation system based on a dynamic vegetation and terrestrial carbon model Vegetation-Global-Atmosphere-Soil （VEGAS） with an advanced assimilation algorithm, the local ensemble transform Kalman filter （LETKF, hereafter LETKF-VEGAS）. An observing system simulation experiment （OSSE） framework was designed to evaluate the reliability of this system, and numerical experiments conducted by the OSSE using leaf area index （LAI） observations suggest that the LETKF -VEGAS can improve the estimations of leaf carbon pool and LAI significantly, with reduced root mean square errors and increased correlation coefficients with true values, as compared to a control run without assimilation. Furthermore, the LETKF-VEGAS has the potential to provide more accurate estimations of the net primary productivity （NPP） and carbon flux to atmosphere （CFta）.  相似文献   

Study on the Evolution of a Northeast China Cold Vortex during the Spring of 2010          下载免费PDF全文

FU Shen-Ming  SUN Jian-Hua  QI Lin-Lin 《大气和海洋科学快报》2014,(2):149-156

Based on the final analysis data with horizontal resolution of 1°× 1°（four times a day） from the National Centers for Environmental Prediction（NCEP）, a typical Northeast China cold vortex（NCCV） during the spring of 2010 was examined with the quasi-Lagrange- form eddy flux circulation（EFC） budget equation. Results indicated that the mechanisms that account for the development, maintenance, and attenuation of the cyclone varied with levels and stages. Displacement of the cyclone and transports by background environmental circulations dominated the variation of the cyclone in the middle and upper levels, whereas displacement and divergence associated with the cyclone dominated the evolution of the NCCV in the middle and lower levels. Moreover, interactions between the NCCV and other subsynoptic weather systems were important for the development of the cyclone, and the pattern of background environmental circulations was also important for the evolution of the NCCV, since the cyclone enhanced（weakened） as it moved from areas of low（high） vorticity to high（low） ones.  相似文献