共查询到20条相似文献，搜索用时 31 毫秒
1.
The purpose of this study is to validate and improve satellite-derived downward surface shortwave radiation (DSSR) over the northwestern Pacific Ocean using abundant in situ data. The DSSR derivation model used here assumes that the reduction of solar radiation by clouds is proportional to the product of satellite-measured albedo and a cloud attenuation coefficient. DSSR is calculated from Geostationary Meteorological Satellite-5/Visible Infrared Spin-Scan Radiometer data in 0.05° × 0.05° grids. The authors first compare the satellite DSSR derived with a cloud attenuation coefficient table determined in past research with in situ values. Although the hourly satellite DSSR agrees well with land in situ values in Japan, it has a bias of +13∼+34 W/m2 over the ocean and the bias is especially large in the low latitudes. The authors then improve the coefficient table using the ocean in situ data. Usage of the new table successfully reduces the bias of the satellite DSSR over the ocean. The cloud attenuation coefficient for low-albedo cases over the ocean needs to be larger in the low latitudes than past research has indicated. Daily and hourly DSSR can be evaluated from the satellite data with RMS errors of 11–14% and 30–33%, respectively, over a wide region of the ocean by this model. It is also shown that the cloud attenuation coefficient over land needs to be smaller than over the ocean because the effect of the radiation reflected by the land surface cannot be ignored. 相似文献
2.
针对SMOS和Aquarius海表盐度误差分析没有区分不同空间频谱信噪特征的问题,基于6种主要的遥感盐度分析产品,根据定性图像、纬向波数谱、均方根误差等指标,分析产品的有效分辨率并探讨其原因机制。研究表明:CATDS-0.25°分析产品所描述的盐度场中小尺度结构失真,其较高谱能量密度在热带海域以噪音为主,而在西边界流等海域以信号为主;BEC-L3-0.25°有着较小的均方根误差、清晰的盐度图像、显著的中尺度能量,最适于描绘中尺度(25~100 km)盐度特征;BEC-L4-0.25°被奇异谱分析方法过度平滑了盐度场;Aquarius-V2-1.00°通过局部平滑处理,在描述大尺度(＞100 km)盐度现象方面表现较好;Aquarius-CAP-1.00°通过主动-被动联合算法(CAP)减小了均方根误差,但图像中卫星轨道形态明显;CATDS-1.00°的图像形态、能量分布和误差特征与Aquarius-V2-1.00°相当。这些结论可为用户正确使用产品进行地球物理学研究提供参考。 相似文献
3.
Comparison of seasonal and interannual variability of snow cover in Russian watersheds according to observations and reanalyses 总被引：1，自引：0，他引：1
V. M. Khan K. G. Rubinshtein A. B. Shmakin 《Izvestiya Atmospheric and Oceanic Physics》2007,43(1):59-69
Seasonal and interannual variability of the water equivalent of snow over the period 1966–1996 is analyzed with the use of the ERA/ECMWF reanalysis data, two versions of the NCEP reanalysis, and ground-based instrumental observations. Regions have been determined where snow characteristics from various sources are most consistent. In general, the snow water equivalent data from the ERA reanalysis are closer to the snow survey data than the NCEP reanalysis data. The best consistency of the water equivalent of snow in the reanalyses with measured data is observed in the period when the snow cover begins to form, in November and December, and the largest discrepancies are found for the snowmelt period, April and May. The interannual variability of the water equivalent in Asian Russia in the 1990s is better reproduced by the NCEP/DOE-II reanalysis. The snow cover data from satellite observations are compared with ground-based instrumental observations. It is shown that large discrepancies between the snow surveys and satellite observations may be observed at the snow-cover boundary during periods of snow formation and snowmelt. 相似文献
4.
Studies on the analysis of the Pacific Ocean surface temperature are presented based on the data of the NCEP/NCAR reanalysis. Two methods are used in the work. The first is a classical analysis of the empirical orthogonal functions (EOFs) that makes it possible to identify the El Niño and La Niña phenomena in tropics. In this case, the anomalies of the ocean surface temperature (OST) are reconstructed during these events with quite high accuracy when using several first EOFs. In contrast, at the time between these events, more harmonics are required for the reconstruction. The OST variability in the middle and high latitudes cannot be identified highly accurately based on this approach, since it is considerably weaker than a strong signal in tropics. This signal was detected by the method of cluster analysis. The results show that, in addition to the signal in tropics, there are well-pronounced quasi-decadal signals between the eastern and western Pacific, as well as in the region of the Kuroshio continuation and in the subpolar gyre that can be identified with Pacific decadal oscillations (PDOs). 相似文献
5.
东、黄海SST与850hPa气温季节变化关系的SVD分析 总被引：2，自引：0，他引：2
利用1998~2004年的热带降雨测量卫星的卫星遥感海表面温度(SST)数据以及美国NO-AA/NCEP再分析产品的850 hPa气温数据,采用EOF分析方法,分析了850 hPa气温的季节内变化特征,运用奇异值分解(SVD)分析方法对东、黄海SST与850 hPa气温季节内变化的相关关系进行了分析。对850 hPa气温季节内变化的EOF分析结果表明,EOF分析获得的前4个模态的累积方差贡献率为86.51%,其中EOF的第一模态的方差贡献率占44.49%,其空间模态呈现出明显的东南海域为正值、西北海域为负值的反相分布特征,这一模态的显著变化周期为6.6周(约46 d)和2.8周(约19 d)。SVD分析结果表明,第一对模态的协方差解释率为83.6%,基本上能体现出SST温度场与850 hPa气温场季节变化的特征,其空间分布型表明,东海北部以及黄海近岸等海区SST季节变化与30°N以南的东海海区850 hPa气温的季节振荡存在显著的正相关关系,SVD第一对模态空间分布型时间系数之间的相关系数达到0.29。 相似文献
6.
Hui Chen Shuang Li Hailun He Jinbao Song Zheng Ling Anzhou Cao Zhongshui Zou Wenli Qiao 《海洋学报(英文版)》2021,40(1):70-84
The present work describes the basic features of super typhoon Meranti(2016) by multiple data sources. We mainly focus on the upper ocean response to Meranti using multiplatform satellites, in situ surface drifter and Argo floats, and compare the results with the widely used idealized wind vortex model and reanalysis datasets.The pre-existing meso-scale eddy provided a favor underlying surface boundary condition and also modulated the upper ocean response to Meranti. Results show that the maximum sea surface cooling was 2.0℃ after Meranti.The satellite surface wind failed to capture the core structure of Meranti as the idealized wind vortex model deduced. According to the observation of sea surface drifters, the near-inertial currents were significantly enhanced during the passage of Meranti. The temperature and salinity profiles from Argo floats revealed both the mixed-layer extension and subsurface upwelling induced by Meranti. The comparison results show that the sea surface temperature and surface wind in the reanalysis datasets differs from those in remote sensing system. Sea surface cooling is similar in both satellite and in situ observation, and sea surface salinity response has a lower correlation with the precipitation rate. 相似文献
7.
Impact of the winter cooling on the variability of the thermohaline characteristics of the active layer in the Black Sea 总被引：1，自引：0，他引：1
The influence of the winter atmospheric forcing on the interannual variability of the Black Sea’s active layer’s thermohaline
structure during 1982–2008 is investigated. The results are based on the combined analysis of the hydrological measurements
from a ship, satellite measurements of the sea’s surface temperature (SST), and the NCEP/NCAR reanalysis data for the surface
air temperature (SAT). A high correlation between the variability of the winter mean SST/SAT and the thermohaline characteristics
of the active layer during the following warm season was found. It is shown that the winter atmospheric forcing significantly
affects the variability of the temperature, salinity, and density down to the 150–200 m depth, and this has to be considered
in the analysis of the interannual and long-term variability of the Black Sea’s active layer. 相似文献
8.
利用渤海和北黄海9个站位浮标的海面10 m气压和风速观测资料对ERA5再分析资料的适用性进行了初步评估。结果表明：海面气压和风速再分析资料与观测资料具有良好的相关性,不同时间尺度的统计结果具有一定差异,累年逐月的相关性优于日均和日极值,极端天气下的相关系数最低。不同时间尺度的统计结果显示,气压再分析资料与观测值的偏差总体为负值,即高压再分析资料较观测值偏弱、低压再分析资料较观测值偏强,二者存在一定的系统性偏差;风速统计结果显示,偏差与风力级别有关,大风速时,风速再分析资料普遍小于观测值。累年逐月再分析资料反映了研究区气压和风速的季节变化特征,偏差也呈现出季节性变化,且冬季的适用性优于夏季;极端天气情况下,气压和风速再分析资料的适用性较差,需要开展进一步的订正处理。 相似文献
9.
基于多源资料进行海面风场的同化融合或插值融合,目前受到计算能力的较大制约。本文提出在多源卫星数据和ERA-5再分析数据重叠区域,训练基于XGBoost的机器学习ERA-5数据修正融合模型。然后基于该模型快速修正ERA-5数据（机器学习推理）。由于机器学习推理的快速性,ERA-5全区域修正融合的时间仅需2 s左右,可以较小计算代价构建整个海面融合风场。本文以10 m风速、10 m风向、U10分量和V10分量等典型风场变量展开,考虑了海陆分布差异使用陆地掩膜消除陆地区域,分别构建D_S_A_XGBoost、D_S_O_XGBoost、U_V_A_XGBoost、U_V_O_XGBoost 4个ERA-5修正模型,并最终生成海面融合风场。通过修正前后的ERA-5再分析数据与卫星数据进行比较,上述4个模型均减小了ERA-5再分析数据与卫星数据的差距。特别是在风速方面,不论是均方根误差（RMSE）还是绝对误差（MAE）都得到有效降低。在风向方面上,RMSEd以及MAEd也呈现降低趋势。在利用热带大气海洋观测计划（Tropical Atmosphere Ocean Array,TAO）浮标数据对4种XGBoost模型进行评价发现,U_V_O_XGBoost模型对于ERA-5数据的修正结果最好,其相关性达到0.893,提高了约0.011,结果表明本文在保证风场精度的情况下较大地提高了融合速度。 相似文献
10.
The authors have verified a regression model for the evaluation of the daily amplitude of sea surface temperature (ΔSST) proposed
by Kawai and Kawamura (2002). The authors investigated the accuracy of satellite data used for the evaluation and showed that
ΔSST error caused by satellite data error is less than ±0.7 K. The evaluated ΔSSTs were compared with in situ values. Its
root-mean-square error is about 0.3 K or less, except for a coastal region, and it has a bias of more than +0.1 K in the tropics.
This bias can be removed by considering latent heat flux.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
11.
Zonal distribution features of high frequency planetary waves in the oceans derived from satellite altimeter data 总被引：2，自引：1，他引：1
1IntroductionTheavailabilityofnearly9aofhighqual-itysealevelanomaly(SLA)datafromsatellitealtimetersmakesitnowpossibletoestimatethedominantsignalsofvariabilityintheglobalo-ceanmoreaccuratelythanwaspreviouslypos-sible.Moreover,mergingtheT/PandERS-1and2altimeterdatathroughanadvancedglobalobjectiveanalysiscangreatlyimproveoura-bilitytoaccuratelyestimateoceanicvariabili-tycomparedwithusingasinglealtimeter(BoulagerandMenkes,1995).ThealtimeterdatarevealthedominantroleofplanetaryRoss-bywavesinocea… 相似文献
12.
A. V. Eliseev I. I. Mokhov A. V. Chernokulsky 《Izvestiya Atmospheric and Oceanic Physics》2017,53(1):1-11
A module for simulating of natural fires (NFs) in the climate model of the A.M. Obukhov Institute of Atmospheric Physics, Russian Academy of Sciences (IAP RAS CM), is extended with respect to the influence of lightning activity and population density on the ignition frequency and fire suppression. The IAP RAS CM is used to perform numerical experiments in accordance with the conditions of the project that intercompares climate models, CMIP5 (Coupled Models Intercomparison Project, phase 5). The frequency of lightning flashes was assigned in accordance with the LIS/OTD satellite data. In the calculations performed, anthropogenic ignitions play an important role in NF occurrences, except for regions at subpolar latitudes and, to a lesser degree, tropical and subtropical regions. Taking into account the dependence of fire frequency on lightning activity and population density intensifies the influence of characteristics of natural fires on the climate changes in tropics and subtropics as compared to the version of the IAP RAS CM that does not take the influence of ignition sources on the large-scale characteristics of NFs into consideration. 相似文献
13.
S. P. Smyshlyaev Ya. A. Virolainen M. A. Motsakov Yu. M. Timofeev A. V. Poberovskiy A. V. Polyakov 《Izvestiya Atmospheric and Oceanic Physics》2017,53(3):301-315
This paper analyzes atmospheric ozone variability at different altitudes over St. Petersburg for the period 2009–2014 on the basis of surface observations at the Peterhof station, satellite measurements with an SBUV instrument, and numerical simulations. Simulation data on temperature, wind velocity, humidity, and surface pressure are taken from the MERRA reanalysis database. Based on ozone measurements, numerical modeling, and reanalysis data, characteristics of ozone seasonal and interannual changes are identified; the role of photochemical and dynamic factors in ozone variations is estimated. 相似文献
14.
针对海表高度计资料的同化,考查了背景误差协方差矩阵的不同求逆方案对同化效果的影响。所使用的求逆方案包括避免求逆的经验正交函数方案(EOF/EOF_var)、递归滤波方案(RF/RF_var)以及采用初等变换法直接求逆的方案(Inv)。基于上述方案开展了热带太平洋地区2002年1-7月的TOPEX/Poseidon高度计资料同化试验,并利用SODA再分析资料和TAO观测资料评估了各方案对温度场的同化效果,主要得到如下结果:与SODA相比较,Inv方案对模式温度场改进甚微,其余四种方案在100~300 m深度之间对温度场改进较多,在其它深度范围内则改进较少;与TAO观测相比较,EOF_var、RF_var方案对模式温度场改进最多,EOF和RF方案次之,Inv方案则对温度场改进甚少。 相似文献
15.
全球海洋高频波动主振荡周期的纬向带状分布特征 总被引：2，自引：2，他引：0
基于1992年10月至2000年12月的TOPEX/Poseidon和ERS-1/2卫星高度计资料,分析了周期短于150d的高频波动及其能量的空间分布特征.在功率谱密度计算基础上,分析特定频段所含能量占周期短于150d的高濒波动总能量的百分比,发现该频段最强振荡(下文称主振荡)所对应的周期从近赤道的1个月逐步增加至南北纬30°附近的4个月,进一步分析表明主振荡周期的这种变化是连续的,与西向行星Rossby波的相速随纬度增加而变慢相对应.主振荡所对应的周期在全球海洋中呈显著的带状分布.进而表明在14°N(S)附近60d周期的振荡除通常所认为的由于潮汐混淆所造成的虚假信号之外,主要是行星Rossby波形态的真实信号. 相似文献
16.
基于HadISST、ERSST和OISST 3种再分析海表面温度数据集，对CESM1全球气候预测系统模拟的重点海域海温的主要模态进行了评估。结果表明，模式能够基本再现再分析资料表征的海表面温度异常时空特征，5个关键海区海表面温度异常EOF分析前两个模态，超前1个月的后报结果均有较高的可预报性。特别是热带太平洋第一模态（ENSO模态），超前3个月的后报与再分析相关系数能够达到0.79，能够为ENSO的预报提供宝贵参考。模式不可避免的存在较多误差，空间上表现为海表面温度异常（SSTA）显著区域的范围以及位置的差异，特别值得注意的是热带印度洋SSTA第一模态存在一个伪印度洋偶极子模态，同时此海区也是3种再分析资料SSTA第一模态空间差异最大的区域；时间序列上均表现出异常高频信号和异常波动情况，误差的大小通常是由同化、超前1月后报、超前3月后报逐渐增大，体现出初始误差随着积分逐渐积累的特征。热带大西洋SSTA第一模态时间序列前5年的位相存在明显偏差，将其剔除后，其时间序列与再分析资料的相关性有实质性改善。 相似文献
17.
E. A. Sharkov G. A. Kim I. V. Pokrovskaya 《Izvestiya Atmospheric and Oceanic Physics》2011,47(9):1084-1091
Energy features of the succession of interrelated tropical cyclones (plural cyclogenesis) in the oceans of the Southern Hemisphere
(the southern part of the Indian Ocean and the southwestern part of the Pacific Ocean) over February 2008 are comprehensively
analyzed on the basis of the method of combining different-scale data of the infrared and radio thermal satellite sounding.
The data of infrared thermal channels of the geostationary Meteosat-7 satellite and the results of reconstruction of integral
water vapor from data of the AMSR-E microwave complex of the Aqua satellite were used. The analysis showed that the region
where water vapor has an increased integral concentration is the most effective channel for pumping the latent heat energy
from the tropics into midlatitudes. Each cyclone captures this region from the tropical zone and retains it throughout the
entire stage of its own evolution with the aid of the jet spiral bridge. The quantitative estimates of the latent energy of
the central equatorial region of water vapor in the intratropical convergence zone (ITCZ) of the Indian and Pacific oceans
were a basically new result, as well as the detection of considerable time variations in the latent heat associated with the
ejection of coherent water-vapor regions into high latitudes by plural cyclogenesis. 相似文献
18.
19.
目前,海洋数据获取量日益增多,根据时空分辨率、时空范围、垂向分层情况等的不同,可将海洋数据分为多种类型。了解和掌握现有的海洋数据资料,并加以利用,对国家经济发展、国防安全、军事活动等具有重要意义。经过长时间的研究和积累,本文总结了国内外海洋数据资料发布的几个主要数据源,同时归纳了几类常用的海洋数据资料,包括地形水深数据、卫星遥感数据、海洋调查观测数据、再分析产品数据,并对各类数据适用的时间尺度、空间尺度进行分析,旨在为海洋领域的科研工作者提供信息支持,为我国海洋大数据的建设提供参考。 相似文献
20.
In the past nearly two decades, the Argo Program has created an unprecedented global observing array with continuous in situ salinity observations, providing opportunities to extend our knowledge on the variability and effects of ocean salinity. In this study, we utilize the Argo data during 2004–2017, together with the satellite observations and a newly released version of ECCO ocean reanalysis, to explore the decadal salinity variability in the Southeast Indian Ocean(SEIO) and its impacts on the regional sea level changes. Both the observations and ECCO reanalysis show that during the Argo era, sea level in the SEIO and the tropical western Pacific experienced a rapid rise in 2005–2013 and a subsequent decline in 2013–2017. Such a decadal phase reversal in sea level could be explained, to a large extent, by the steric sea level variability in the upper 300 m. Argo data further show that, in the SEIO, both the temperature and salinity changes have significant positive contributions to the decadal sea level variations. This is different from much of the Indo-Pacific region, where the halosteric component often has minor or negative contributions to the regional sea level pattern on decadal timescale. The salinity budget analyses based on the ECCO reanalysis indicate that the decadal salinity change in the upper 300 m of SEIO is mainly caused by the horizontal ocean advection. More detailed decomposition reveals that in the SEIO, there exists a strong meridional salinity front between the tropical low-salinity and subtropical high salinity waters. The meridional component of decadal circulation changes will induce strong cross-front salinity exchange and thus the significant regional salinity variations. 相似文献