A multi-scale second-order autoregressive recursive filter approach for the sea ice concentration analysis

To effectively extract multi-scale information from observation data and improve computational efficiency,a multi-scale second-order autoregressive recursive filter(MSRF)method is designed.The second-order autoregressive filter used in this study has been attempted to replace the traditional first-order recursive filter used in spatial multi-scale recursive filter(SMRF)method.The experimental results indicate that the MSRF scheme successfully extracts various scale information resolved by observations.Moreover,compared with the SMRF scheme,the MSRF scheme improves computational accuracy and efficiency to some extent.The MSRF scheme can not only propagate to a longer distance without the attenuation of innovation,but also reduce the mean absolute deviation between the reconstructed sea ice concentration results and observations reduced by about 3.2%compared to the SMRF scheme.On the other hand,compared with traditional first-order recursive filters using in the SMRF scheme that multiple filters are executed,the MSRF scheme only needs to perform two filter processes in one iteration,greatly improving filtering efficiency.In the two-dimensional experiment of sea ice concentration,the calculation time of the MSRF scheme is only 1/7 of that of SMRF scheme.This means that the MSRF scheme can achieve better performance with less computational cost,which is of great significance for further application in real-time ocean or sea ice data assimilation systems in the future.

Climate prediction of the seasonal sea-ice early melt onset in the Bering Sea

基于大尺度环流异常对海冰消融的影响过程,本文采用年际增量预测方法研制了白令海季节性海冰早期消融开始日期(EMO)的统计预测模型.预测模型选取了3个具有明确物理意义的预测因子:1月波弗特高压,前期11月东西伯利亚地区海平面气压,以及11月东欧平原积雪覆盖率。1月波弗特高压可以通过海气相互作用影响白令海地区海温异常,该海温异常能够从1月持续到3月,进而影响白令海EMO.11月东西伯利亚地区海平面气压与11月至次年2月北太平洋中纬度东部海温密切相关。伴随着北太平洋中纬度东部冷海温异常的出现,白令海地区会出现暖海温异常,进而导致白令海海冰范围减少,EMO较晚.1月北极偶极子异常是11月东欧平原积雪覆盖率影响次年白令海EMO的桥梁之一.1981-2022年的交叉检验结果表明:统计模型对白令海EMO具有较好的预测能力,预测与观测的EMO之间时间相关系数达到了0.45,超过了99%的置信水平.统计模型对白令海EMO正常年份和异常年份的预测准确率分别为60%和41%.

Revisiting the Seasonal Evolution of the Indian Ocean Dipole from the Perspective of Process-Based Decomposition

The seasonal phase-locking feature of the Indian Ocean Dipole(IOD)is well documented.However,the seasonality ten-dency of sea surface temperature anomalies(SSTAs)during the development of the IOD has not been widely investigated.The SSTA tendencies over the two centers of the IOD peak in September-October-November are of different monthly amplitudes.The SSTA tendency over the west pole is small before June-July-August but dramatically increases in July-August-September.Meanwhile,the SSTA tendency over the east pole gradually increases before June-July-August and decreases since then.The growth rate attribution of the SSTAs is achieved by examining the roles of radiative and non-radiative air-sea coupled thermodynamic processes through the climate feedback-response analysis method(CFRAM).The CFRAM results indicate that oceanic dynamic processes largely contribute to the total SSTA tendency for initiating and fueling the IOD SSTAs,similar to previous studies.However,these results cannot ex-plain the monthly amplitudes of SSTA tendency.Four negative feedback processes(cloud radiative feedback,atmospheric dynamic processes,surface sensible,and latent heat flux)together play a damping role opposite to the SSTA tendency.Nevertheless,the sea surface temperature-water vapor feedback shows positive feedback.Specifically,variations in SSTAs can change water vapor con-centrations through evaporation,resulting in anomalous longwave radiation that amplifies the initial SSTAs through positive feedback.The effect of water vapor feedback is well in-phase with the monthly amplitudes of SSTA tendency,suggesting that the water vapor feedback might modulate the seasonally dependent SSTA tendency during the development of the IOD.

Responses of the Sea Surface Temperature and Suspended Matter Concentration to ENSO Events in the Bohai Sea

The sea surface temperature(SST)and sea surface suspended matter concentration data in the Bohai Sea were collected by multiple NOAA satellites from 1985 to 2018.The background calibration method was used to correct the systematic errors caused by the long-term observations through multiple NOAA satellites in this paper.Then,we studied the long-term variations of the sea surface temperature(SST)and sea surface suspended matter concentration(SSC)and their response to ENSO events in the Bohai Sea.Our results show that the SST and SSC of the Bohai Sea have been increasing since 1985,with an average rate of 0.04℃per year for SST,which is higher than the global average.The average increasing rate of SSC was 0.51 mg L^(-1)yr^(-1),which may be mainly due to the enhancement of winter monsoon in the Bohai.In winter,the SST and SSC of the Bohai Sea were higher in El Niño years than in La Niña years.In El Niño years,the ocean circulations were the main factor affecting the variation in SST.The robust circulation system caused by the strong winter monsoon enhances the water exchange between the cold water of the Bohai Sea and the warm water of the Yellow Sea,resulting in a higher SST in La Niña years.In summer,the SSTs of the Bohai Sea were lower in El Niño years than those in the La Niña years because of the decrease of the SST in the Western Pacific Ocean,the weakening of the subtropical high in the western Pacific,and its eastward shift caused by the El Niño events.

A Parameterization Scheme for Wind Wave Modules that Includes the Sea Ice Thickness in the Marginal Ice Zone

The global wave model WAVEWATCH III®works well in open water.To simulate the propagation and attenuation of waves through ice-covered water,existing simulations have considered the influence of sea ice by adding the sea ice concentration in the wind wave module;however,they simply suppose that the wind cannot penetrate the ice layer and ignore the possibility of wind forcing waves below the ice cover.To improve the simulation performance of wind wave modules in the marginal ice zone(MIZ),this study proposes a parameterization scheme by directly including the sea ice thickness.Instead of scaling the wind input with the fraction of open water,this new scheme allows partial wind input in ice-covered areas based on the ice thickness.Compared with observations in the Barents Sea in 2016,the new scheme appears to improve the modeled waves in the high-frequency band.Sensitivity experiments with and without wind wave modules show that wind waves can play an important role in areas with low sea ice concentration in the MIZ.

Obtaining accurate measurements of the sea surface height from a GPS buoy

A dedicated GPS buoy is designed for calibration and validation(Cal/Val)of satellite altimeters since 2014.In order to evaluate the accuracy of the sea surface height(SSH)measured by the GPS buoy,twelve campaigns have been done within China sea area between 2014 and 2021.In six of these campaigns,two static Global Navigation Satellite System stations were installed at distances of<1 km and 19 km from the buoy to assess how the baseline length influenced the derived SSH from the buoy solutions.The GPS buoy data was processed using the GAMIT/GLOBK software+TRACK module and CSRS-PPP tool to achieve the SSH.The SSH was compared with conventionally tide gauge(TG)data to evaluate the accuracy of the buoy with the standard deviation of the height element.The results showed that the difference in the standard deviation of the SSH from the buoy and the TG was less than 16 mm.The SSHs processed with different ephemeris(Ultra-Rapid,Rapid,Final)were not significantly different.When the baseline length was 19 km,the SSH solution of the GPS buoy performed well,with standard bias of less than 26 mm between the heights measured by the buoy and TG,meaning that the buoy could be used for Cal/Val of altimeters.The bias between the Canadian Spatial Reference System-precise point positioning tool and the TRACK varied a lot,and some of them were over 130 mm.This deemed too high to be useful for Cal/Val of satellite altimeters.Moreover,the GPS buoy solutions processed by GAMIT/GLOBK software+TRACK module were used for in-orbit Cal/Val of HY-2B/C satellites in ten campaigns.The SSH and significant wave height of the altimeters showed good agreements with the GPS buoy solutions.

A new decomposition model of sea level variability for the sea level anomaly time series prediction

Rising sea level is of great significance to coastal societies;predicting sea level extent in coastal regions is critical.When carrying out predictions,the subsequences obtained using decomposition methods may exhibit a certain regularity and therefore can provide multidimensional information that can be used to improve prediction models.Traditional decomposition methods such as seasonal and trend decomposition using Loess(STL)focus mostly on the fluctuating trend of time series and ignore its impact on prediction.Methods in the signal decomposition domain,such as variational mode decomposition(VMD),have no physical significance.In response to the above problems,a new decomposition method for sea level anomaly time series prediction(DMSLAP)is proposed.With this method,the trend term in a time series can be isolated and the effects of abnormal sea level change behaviors can be attenuated.We decompose multiperiod characteristics using this method while maintaining the smoothness of the analyzed series.Satellite altimetry data from 1993 to 2020 are used in experiments conducted in the study area.The results are then compared with predictions obtained using existing decomposition methods such as the STL and VMD methods and time varying filtering based on empirical mode decomposition(TVF-EMD).The performance of DMSLAP combined with a prediction method resulted in optimal sea level anomaly(SLA)predictions,with a minimum root mean square error(RMSE)of 1.40 cm and a maximum determination coefficient(R^(2))of 0.93 during 2020.The DMSLAP method was more accurate when predicting 1-year data and 3-year data.The TVF-EMD and DMSLAP methods had comparable accuracies,and the periodic term decomposed by the DMSLAP method was more in line with the actual law than that derived using the TVF-EMD method.Thus,DMSLAP can decompose SLA time series better than existing methods and is an effective tool for obtaining short-term SLA prediction.

Blend with the Sea Surface Temperature from Different Satellites and Their Comparison in the Southeast Pacific Ocean

The daily sea surface temperature(SST)data from three kinds of different satellites of GMI,GOES and MODIS were applied to do the blend in the Southeast Pacific Ocean throughout the whole year of 2020.The coverage rates of the SST of the blend result were improved highly and more stable throughout the whole year,compared with the result of the single satellite of GMI,GOES,and MODIS.The yearly average coverage rates of GMI,GOES,MODIS,and blend were 43%,48%,30%,and 76%,and their corresponding yearly average standard deviation(SD)were 4%,6%,7%,and 4%,respectively.All the coverage rates of these three satellites were low from April to September.The valid observation days calculated in the whole year over every grid were used to represent the spatial distribution patterns of the coverage rates.The spatial distribution patterns of coverage rates from GOES and MODIS were similar that their valid observation days were higher in the northwest area and lower in the south area,and those of GMI was contrary to the former two.The ranges of valid observation day was from GOES,GMI,and MODIS were 0-364,6-254,and 9-231 d,respectively.After the blend,all the observation day of every grid in the research region was enhanced(103-366 d).Especially the near shore and south area,and the minimum valid observation day increased largely from the single digits to hundreds digit.

Genetic diversity and population structure of the sea star Asterias amurensis in the northern coast of China

The sea star Asterias amurensis is widely viewed as a severe“marine pest”because of its broad feeding habits.Over the past few decades,A.amurensis undergoes massive and sporadic population outbreaks worldwide,causing extensive economic and ecological losses to the local aquaculture industry and marine ecosystem.Understanding the genetic diversity and population structure of A.amurensis can provide vital information for resource management.By analyzing the polymorphism of the mitochondrial cytochrome C oxidase subunit I(COI)gene and ten simple sequence repeat(SSR)microsatellites markers,the genetic diversity and population structure of A.amurensis of four populations along the northern coast of China was uncovered.A total of 36 haplotypes were identified,and a main haplotype was found in four populations.The Qingdao(QD)population displayed the highest genetic diversity among all the populations.The AMOVA and pairwise F_(st)showed that there was small but statistically significant population differentiation among the four populations,especially between QD and Weihai(WH).Moreover,the principal component analysis(PCA)and admixture analysis showed that several individuals in Yantai(YT)and Dalian(DL)had little genetic association with other individuals.Overall,this study provided useful information of the genetic diversity and population structure of A.amurensis and will contribute to the resource management of A.amurensis in China.

Geocriticism of The Old Man and the Sea

“The old man”and“the sea”are two essential parts of The Old Man and the Sea;however,most critics have given priority to“the old man”when interpreting the short novel.This essay thinks that the sea is not just a setting for action and attempts to explore the multiple meaning of the sea from the perspective of geocriticism.With theories of Westphal’s geocriticism and Tally’s literary cartography,it analyzes what the sea as geography does to the old man,how the sea is crucial to Hemingway’s writing and how Hemingway maps the sea.Geocriticism of the novella offers new insights in understanding literature.

Mixed layer in the Sea of Japan:numerical simulation andlong-term data analysis

Seasonal variation and topography of the mixed layer in the Sea of Japan are studied by comparison of results from long-term observation data analysis and from numerical simulation with the MHI oceanic model (Shapiro. 1998. Marine Hydrophysical Journal, 6: 26-40). The data are retrieved from Oceanographic A tlas of the Bering Sea, Okhotsk Sea, and Japan/East Sea (Rostov, Rostov, Dmitrieva, et al. 2003. Pacific Oceanography, 1(1):70-72). The simulated and long-term patterns are compared. An impact of surface buoyancy flux, wind, and convergence/divergence of surface currents upon the mixed layer in the Sea of Japan is analyzed.

Effect of non-Gaussian properties of the sea surface on the low-incidence radar backscatter and its inversion in terms of wave spectra by an ocean wave spectrometer

The principle of ocean wave spectrometers was first presented several decades ago to detect the directional wave spectrum with real-aperture radar(Jackson,1981). To invert wave spectra using an ocean wave spectrometer,for simplicity,the hydrodynamic forcing and wave-wave interaction effect are neglected and a Gaussian slope probability density function(pdf) is used to calculate the normalized backscattering cross-section( σ 0) of the ocean surface. However,the real sea surface is non-Gaussian. It is not known whether the non-Gaussian property of the sea surface will affect the performance of the inversion of the wave spectrum if following existing inversion steps and methods. In this paper,the pdf of the sea surface slope is expressed as a Gram-Charlier fourth-order expansion,which is quasi-Gaussian. The modulation transfer function(MTF) is derived for a non-Gaussian slope pdf. The effects of non-Gaussian properties of the sea surface slope on the inversion process and result are then studied in a simulation of the SWIM(Surface Waves Investigation and Monitoring) instrument configuration to be used on the CFOSAT(China-France Oceanography Satellite) mission. The simulation results show that the mean trend of σ 0 depends on the sea slope pdf,and the peakedness and skewness coefficients of the slope pdf affect the shape of the mean trend of σ 0 versus incidence and azimuth; owing to high resolution of σ 0 in the range direction,MTF obtained using the mean trend of σ 0 is almost as accurate as that set in the direct simulation; in the inversion,if ignoring the non-Gaussian assumption,the inversion performances for the wave spectrum decrease,as seen for an increase in the energy error of the inverted wave slope spectrum. However,the peak wavelength and wave direction are the same for inversions that consider and ignore the non-Gaussian property.

Research on ＂three zone＂ classification of spontaneous combustion and its numerical simulation in gob of mines under the sea

According to the classification standard of spontaneous combustion ＂three zone＂ in gob and the analysis of aerodynamics and energy equation of relax loose coal body, the paper used the method of computer simulation analysis to get the air distribution. The paper also determined the three zone area of H2103 fully mechanized caving face in Beizao Mine.

Tentative Interpretation of The Old Man and the Sea

本文试图解析《老人与海》中老人和海的形象，认为小说中的老人是勇气、智慧和尊严的象征，是一个圣者，同时又具有常人的弱点；并认为老人对大海未知领域的探求是海明威自身的写照。小说中的大海不仅是一种神秘、巨大、与人为敌的自然力量，也是一种和善、能与人类相容的女人、兄弟和朋友。同时还认为老人与大海的结合一方面是老人一生与海相搏以达到相容的结果，同时也是他们自身和善、任性的产物。通过塑造两个形象，海明威在人物、小说背景安排和主题上实现了突破。在晚年，他更关心日常生活中的常人和他们所处的环境，对他们的勇气、智慧、特别是尊严给予高度赞扬。老人是海明威一生创作的这一系列＂英雄＂群像的一个新的里程碑，是其一生乐观主义精神追求的最终结果。

NUMERICAL SIMULATION ON RE-INTENSIFICATION OF TROPICAL REMNANT RE-ENTERING THE SEA:A CASE STUDY

When Typhoon Toraji(2001)reached the Bohai Gulf during 1-2 August 2001,a heavy rainfall event occurred over Shandong province in China along the gulf.The Advanced Research version of the Weather Research and Forecast(WRF-ARW)model was used to explore possible effects of environmental factors,including effects of moisture transportation,upper-level trough interaction with potential vorticity anomalies,tropical cyclone(TC)remnant circulation,and TC boundary-layer process on the re-intensification of Typhoon Toraji,which re-entered the Bohai Gulf after having made a landfall.The National Centers for Environmental Prediction(NCEP)global final(FNL)analysis provided both the initial and lateral boundary conditions for the WRF-ARW model.The model was initialized at 1200 UTC on 31 July and integrated until 1200 UTC on 3 August 2001,during which Toraji remnant experienced the extratropical transition and re-intensification.Five numerical experiments were performed in this study,including one control and four sensitivity experiments.In the control experiment,the simulated typhoon had a track and intensity change similar to those observed.The results from three sensitivity experiments showed that the moisture transfer by a southwesterly lower-level jet,a low vortex to the northeast of China,and the presence of Typhoon Toraji all played important roles in simulated heavy rainfall over Shandong and remnant re-intensification over the sea,which are consistent with the observation.One of the tests illustrated that the local boundary layer forcing played a secondary role in the TC intensity change over the sea.

Distribution of chlorophyll a and diatom in the sea ice of the Weddell Sea, Antarctica

Diatoms are major primary producers of microbial biomass in the Antarctica. They are found in the water and sea ice. The distribution, abundance of the ice diatoms and their relation to the environmental factors inside and outside the ice have been studied for its special role in the Antarctic Ocean ecology. In this paper we describe the abundance, distribution and composition of diatom assemblages in

Numerical analysis of the sea (lake ) breeze dynamics and initialization of the model

In this paper, analysed are the effects of synoptic wind, earth-rotation inertia and land surface roughness on sea (lake) breeze process, on the basis of the calculated results of a 2-D primitive equation model with turbulent energy closure. The results show that a moderate background wind field acts as a trigger for sea (lake) breeze onset, and presents prominent effect on the breeze intensity, inland advance rate and structure feature. The effects of Coriolis force not only make the breeze veering round, but also damp the development of the breeze component normal to shore.The paper also discussed the dynamic method of wind field initialization based on one-site radiosonde. Three approaches of initialization have been tested. In comparison, it was found that the approach of one-dimensional dynamic initialization with nudging term was preferable to the others.

The PNA wavetrain and the sea surface temperature in the Northern Pacific

In this paper, the response of the atmospheric 3-5 year cycle to Northern Pacific SST is discussed, The results are as follows:1. From the simultaneous temporal correlations between the Equatorial Eastern Pacific SST, the westerly dirft area's SST and the Northern Pacific SST at all gridpoints, we find that there are three correlative regions in the Northern Pacific SST field, they are the westerly drift area, the Equatorial Eastern Pacific and the Alaska Bay , and their structures are very similar to the PNA pattern in the atmosphere The difference PTI between the Equatorial Eastern Pacific SST anomaly and the westerly drift area's SST anomaly can indicate the change of the PNA pattern of the Northern Pacific SST anomaly. It can represent SST change of 65 % areas over the Northern Pacific and can keep watch on El Nino and un-El Nino.2. Simultaneous temporal correlative field between PTI and filtered 500hPa (there is 3-5 year cycle only ) of the Northern Hemisphere presents clear PNA structure. The responses of the filtered 500hPa to El Nino and to un-EI Nino produce +PNA and -PNA wavetrains respectively.3. According to the different positions of the sea-surface temperature rise (drop) ,El Nino (un-EI Nino )can be divided into two classes: east-pattern and middle-pattern. The responses of the filtered 500hPa to the east-pattern and to the middle-pattern will produce PNA and EAA wavetrain respectively. This indicates that the responses of the atmosphere to the stationary heat sources in diffrent areas will produce wavetrains in diffrent track.

Numerical modelling of the sea level under the actions of the tide and strong wind in the Bohai Sea

In this paper, the numerical modelling of the tidal level and current in the Bohai Sea was carried out with ADI method, by taking the sum of four main tidal components M2,S2K2,O1 as the open boundary condition. The calculated values were consistent with the predicted ones (the observed values in the case of calm) in the Tidal Table. On the basis of the modelling of the tide, the sea level and current fields under the effects of strong wind were simulated. The calculated results were also quite satisfactory.

DISSOLVED OXYGEN DISTRIBUTION AND O_2 FLUXES ACROSS THE SEA-AIR INTERFACE IN EAST CHINA SEA WATERS

This study on the sectional and vertical distribution of dissolved oxygen (DO) and the O_2 fluxes acrossthe sea-air interface in East China Sea (ESC) waters shows that the waters were in steady state and thatthe difference of DO was great in upper and bottom waters in Apr. 1994; but that seawater mixingwas strong and the difference of DO was small in upper and bettom waters in Oct. 1994. The above con-dusions were specially obvious in continental shelf waters under 100m. The DO maximum in subsurfacelayer waters appeared only at several stations and in general the DO in the waters decreased with depth.The horizontal distributions of O_2 fluxes across the sea-air interface appeared in stripes in Leg 9404 whenmost regions covend were supersaturated with O_2. seawater to air flux wn large, and that on section No.1was 1.594 L/m^2·d. The horizontal distribution of O_2 fluxes across the sea-air interface appeared lumpy inLeg 9410, when most regions covered were unsaturated with O_2. O_2 was dissolved from air to seawater,and the fluxes were 0.819 L/m^2·d on section No. 1 in Leg 9310, 0.219 L/m^2·d in Leg 9410. The mainreasons for DO change in surface layer seawater were the mixture of upper and bottom layer water, and theexchange of O_2 across the sea-air interface. The variation of DO by biological activity was only 20% of totalchange of DO.