The muhiyear averaged surface current field and seasonal variability in the Kuroshio and adjacent regions are studied. The data used are trajectories and （1/4） ° latitude by （1/4） ° longitude mean curren...The muhiyear averaged surface current field and seasonal variability in the Kuroshio and adjacent regions are studied. The data used are trajectories and （1/4） ° latitude by （1/4） ° longitude mean currents derived from 323 Argos drifters deployed by Chinese institutions and world ocean circulation experiment from 1979 to 2003. The results show that the Kuroshio surface path adapts well to the western boundary topography and exhibits six great turnings. The branching occurs frequently near anticyclonic turnings rather than near cyclonic ones. In the Luzon Strait, the surface water intrusion into the South China Sea occurs only in fall and winter. The Kuroshio surface path east of Taiwan, China appears nearly as straight lines in summer, fall, and winter, when anticyclonic eddies coexist on its right side; while the path may cyclonically turning in spring when no eddy exists. The Kuroshio intrusion northeast of Taiwan often occurs in fall and winter, but not in summer. The running direction, width and velocity of the middle segment of the Kuroshio surface currents in the East China Sea vary seasonally. The northward intrusion of the Kuroshio surface water southwest of Kyushu occurs in spring and fall, but not in summer. The northmost position of the Kuroshio surface path southwest of Kyushu occurs in fall, but never goes beyond 31 °N. The northward surface current east of the Ryukyu Islands exists only along Okinawa-Amami Islands from spring to fall. In particular, it appears as an arm of an anti- cyclonic eddy in fall.展开更多
Based on HYbrid Coordinate Ocean Model (HYCOM) assimilation and observations, we analyzed seasonal variability of the salinity budget in the southeastern Arabian Sea (AS) and the southern part of the Bay of Bengal (BO...Based on HYbrid Coordinate Ocean Model (HYCOM) assimilation and observations, we analyzed seasonal variability of the salinity budget in the southeastern Arabian Sea (AS) and the southern part of the Bay of Bengal (BOB), as well as water exchange between the two basins. Results show that fresh water flux cannot explain salinity changes in salinity budget of both regions. Oceanic advection decreases salinity in the southeastern AS during the winter monsoon season and increases salinity in the southern BOB during the summer monsoon season. In winter, the Northeast Monsoon Current (NMC) carries fresher water from the BOB westward into the southern AS; this westward advection is confined to 4°-6°N and the upper 180 m south of the Indian peninsula. Part of the less saline water then turns northward, decreasing salinity in the southeastern AS. In summer, the Southwest Monsoon Current (SMC) advects high-salinity water from the AS eastward into the BOB, increasing salinity along its path. This eastward advection of high-salinity water south of the India Peninsula extends southward to 2°N, and the layer becomes shallower than in winter. In addition to the monsoon current, the salinity difference between the two basins is important for salinity advection.展开更多
Deoxygenation has frequently appeared in coastal ecosystems over the past century due to the joint infl uence of increasing anthropogenically induced nutrient inputs and global warming.The semi-enclosed Bohai Sea is a...Deoxygenation has frequently appeared in coastal ecosystems over the past century due to the joint infl uence of increasing anthropogenically induced nutrient inputs and global warming.The semi-enclosed Bohai Sea is a typical system that is prone to deoxygenation,with regular hypoxia events consistently recorded in recent decades.Based on in-situ observation data collected in large-scale voyage surveys in the Bohai Sea during 2008-2017,the seasonal variability in dissolved oxygen(DO)and its controlling mechanisms were studied.The results indicated that in spring and autumn,the DO distributions exhibited similar spatial patterns in the surface and bottom layers,while in summer,its spatial distribution was characterized by large-scale oxygen-poor zones distributed off the Qinhuangdao Coast and the central southern Bohai Sea in the bottom layer.The controlling mechanisms of the DO distribution varied from season to season.Spring and autumn DO distributions were dominated by the seawater temperature.Under the combined eff ects of stratifi cation and decomposition,the summer bottom DO exhibited dual-core distribution.On the one hand,stratifi cation could greatly impede vertical mixing,resulting in reduced bottom DO replenishment.On the other hand,the increased bottom organic matter intensifi ed the decomposition processes,inducing massive DO consumption and elevated dissolved inorganic nitrogen concentrations.In addition,the stronger stratifi cation might be the reason for the more severe deoxygenation in the southern oxygen-poor zones in summer.Our study provides guidance for an in-depth understanding of the DO seasonality in the Bohai Sea and the mechanisms that modulate it and for the improvement of hypoxia forecasts in ocean models.展开更多
The seasonal variability of tropical cyclones （CTCs） generated over the South China Sea （SCS） from 1948 to 2003 is analyzed. It peaks in occurrence in August and few generate in late winter （from January to March...The seasonal variability of tropical cyclones （CTCs） generated over the South China Sea （SCS） from 1948 to 2003 is analyzed. It peaks in occurrence in August and few generate in late winter （from January to March）. The seasonal activity is attributed to the variability of atmosphere and ocean environments associated with the monsoon system. It is found that the monsoonal characteristics of the SCS basically determine the region of tropical cyclone （TC） genesis in each month.展开更多
Using the 28℃ isotherm to define the Western Pacific Warm Pool （WPWP）, this study analyzes the seasonal variability of the WPWP thermohaline structure on the basis of the monthly-averaged sea temperature and salini...Using the 28℃ isotherm to define the Western Pacific Warm Pool （WPWP）, this study analyzes the seasonal variability of the WPWP thermohaline structure on the basis of the monthly-averaged sea temperature and salinity data from 1950 to 2011, and the dynamic and thermodynamic mechanisms based on the monthly-averaged wind, precipitation, net heat fluxes and current velocity data. A△T=-0.4℃ is more suitable than other temperature criterion for determining the mixed layer （ML） and barrier layer （BL） over the WPWP using monthly-averaged temperature and salinity data. The WPWP has a particular thermohaline structure and can be vertically divided into three layers, i.e., the ML, BL, and deep layer （DL）. The BL thickness （BLT） is the thickest, while the ML thickness （MLT） is the thinnest. The MLT has a similar seasonal variation to the DL thickness （DLT） and BLT. They are all thicker in spring and fall but thinner in summer. The temperatures of the ML and BL are both higher in spring and autumn but lower in winter and summer with an annual amplitude of 0.15℃, while the temperature of the DL is higher in May and lower in August. The averaged salinities at these three layers are all higher in March but lower in September, with annual ranges of 0.41-0.45. Zonal currents, i.e., the South Equatorial Current （SEC） and North Equatorial Counter Current （NECC）, and winds may be the main dynamic factors driving the seasonal variability in the WPWP thermohaline structure, while precipitation and net heat fluxes are both important thermodynamic factors. Higher （lower） winds cause both the MLT and BLT to thicken （thin）, a stronger （weaker） NECC induces MLT, BLT, and DLT to thin （thicken）, and a stronger （weaker） SEC causes both the MLT and BLT to thicken （thin） and the DLT to thin （thicken）. An increase （decrease） in the net heat fluxes causes the MLT and BLT to thicken （thin） but the DLT to thin （thicken）, while a stronger （weaker） precipitation favors thinner （thicker） MLT but thicker （thinner） BLT and DLT. In addition, a stronger （weaker） NECC and SEC cause the temperature of the three layers to decrease （increase）, while the seasonal variability in salinity at the ML, BL, and DL might be controlled by the subtropical cell （STC）.展开更多
The turbidity maximum zone(TMZ) is one of the most important regions in an estuary.However,the high concentration of suspended material makes it difficult to measure the partial pressure of CO_2(pCO_2) in these region...The turbidity maximum zone(TMZ) is one of the most important regions in an estuary.However,the high concentration of suspended material makes it difficult to measure the partial pressure of CO_2(pCO_2) in these regions.Therefore,very little data is available on the pCO_2 levels in TMZs.To relatively accurately evaluate the CO_2 flux in an example estuary,we studied the TMZ and surrounding area in the Changjiang(Yangtze) River estuary.From seasonal cruises during February,August,November 2010,and May 2012,the pCO_2 in the TMZ and surrounding area was calculated from pH and total alkalinity(TA)measured in situ,from which the CO_2 flux was calculated.Overall,the TMZ and surrounding area acted as a source of atmosphere CO_2 in February and November,and as a sink in May and August.The average FCO_2was-9,-16,5,and 5 mmol/(m^2·d) in May,August,November,and February,respectively.The TMZ's role as a source or sink of atmosphere CO_2 was quite different to the outer estuary.In the TMZ and surrounding area,suspended matter,phytoplankton,and pH were the main factors controlling the FCO_2,but here the influence of temperature,salinity,and total alkalinity on the FCO_2 was weak.Organic carbon decomposition in suspended matter was the main reason for the region acting as a CO_2 source in winter,and phytoplankton production was the main reason the region was a CO_2 sink in summer.展开更多
A coupled ice-ocean isopycnal numerical model of the Southern Ocean is established tostudy the circulation and its seasonal variability in the region around the Kerguelen Plateau. An analysis of the simulated results ...A coupled ice-ocean isopycnal numerical model of the Southern Ocean is established tostudy the circulation and its seasonal variability in the region around the Kerguelen Plateau. An analysis of the simulated results shows significant stripe-like structure and non-zonal feature of the Antarctic Cir-cumpolar Current (ACC) in this region. ACC begins to bifurcate and to turn its direction before meeting the plateau. The southernmost branch of ACC is near to the Antarctic coast and displays its strong interaction with the westward Antarctic Slope Current. The northern branch of ACC has a tendency of annual variations while the southern one varies in a semiannual cycle. The variation phases of both branches are coincident with that of the wind stress in this region.展开更多
The chlorophyll a(Chl a)is an important indicator of marine ecosystems.The spatiotemporal variation of the Chl a greatly aff ects the mariculture and marine ranching in coastal waters of the Shandong Peninsula.In the ...The chlorophyll a(Chl a)is an important indicator of marine ecosystems.The spatiotemporal variation of the Chl a greatly aff ects the mariculture and marine ranching in coastal waters of the Shandong Peninsula.In the current study,the climatology and seasonal variability of surface Chl-a concentration around the Shandong Peninsula are investigated based on 16 years(December 2002-November 2018)of satellite observations.The results indicate that the annual mean Chl-a concentration is greater in the Bohai Sea than in the Yellow Sea and decreases from coastal waters to off shore waters.The highest Chl-a concentrations are found in Laizhou Bay(4.2-8.0 mg/m^(3)),Haizhou Bay(4.2-5.9 mg/m^(3))and the northeast coast of the Shandong Peninsula(4.4-5.0 mg/m^(3)),resulting from the combined eff ects of the intense riverine input and long residence time caused by the concave shape of the coastline.The seasonal Chl-a concentration shows a significant spatial variation.The Chl-a concentrations in these three subregions generally exhibit an annual maximum in August/September,due to the combined eff ects of sea surface temperature,river discharge and sea surface wind.In the southeast coast region,however,the Chl-a concentration is lowest throughout the year and reaches a maximum in February with a minimum in July,forced by the seasonal evolution of the Yellow Sea Cold Water and monsoon winds.The interannual Chl-a concentration trends vary among regions and seasons.There are significant increasing trends over a large area around Haizhou Bay from winter to summer,which are mainly caused by the rising sea surface temperature and eutrophication.In other coastal areas,the Chl-a concentration shows decreasing trends,which are clearest in summer and induced by the weakening land rainfall.This study highlights the differences in the Chl-a dynamics among regions around the Shandong Peninsula and is helpful for further studies of coupled physical-ecological-human interactions at multiple scales.展开更多
As the spatio-temporal variability of the Kuroshio is highly influenced by mesoscale eddies, representing its seasonal variability characteristics requires sufficiently long term observations to reduce the uncertainti...As the spatio-temporal variability of the Kuroshio is highly influenced by mesoscale eddies, representing its seasonal variability characteristics requires sufficiently long term observations to reduce the uncertainties. Geostrophic velocity data estimated from hydrographic observation from 1987 to 2010 and the shipboard ADCP velocity data from 1993 to 2008 at the PN Section in the central East China Sea are collected to view the seasonal variability objectively. From both types of observation, it is found that the seasonal climatology mean of the Kuroshio Current exhibits significant difference in three areas, which are located at the Kuroshio Current core and its two flanks in a shallow layer less than 300 m, with the weakest northeast current at the core in autumn, the strongest counter current on the right flank in spring, and the strongest northeast current on the left flank in autumn, respectively. The seasonal variance of the Kuroshio Current also exhibits significant difference on the off- shore side of the Kuroshio, with larger variance in spring and summer while smaller variance in autumn and winter. For the current parallel to the PN Section, the ratio of the seasonal variability component to the intraseasonal variability component is relatively smaller than that for the current perpendicular to the PN Section. Further analyses indicate that the seasonal variability at the PN Section is tightly linked to the upstream and downstream current variability.展开更多
Four sections of expendable conductivity-temperature-depth （XCTD） profiles from Fremantle, Australia to Antarctic Zhongshan Station and Moderate Resolution Imaging Spectroradiometer-Aquarius （MODIS-A） sea surface ...Four sections of expendable conductivity-temperature-depth （XCTD） profiles from Fremantle, Australia to Antarctic Zhongshan Station and Moderate Resolution Imaging Spectroradiometer-Aquarius （MODIS-A） sea surface temperature （SST） products were used to study the structure and seasonal variability of Southeast Indian Ocean fronts. Water mass analysis showed that surface water masses in the Southeast Indian Ocean were less salty in March than in November. Compared with November, the subtropical front （STF） moved southward about one degree of latitude in March, whereas seasonal variability of the subantarctic front （SAF） and polar front （PF） locations was not obvious. In March, the saline front moved northward about two degrees of latitude relative to the thermal front in the upper 100 m at the SAF, which was the northern boundary of sub- Antarctic surface water （SASW）. Analysis of climatological SST gradients from the satellite data showed that regions of enhanced sea surface temperature （SST） gradients were collocated with frontal locations identified with the XCTD data using water mass criteria. The surface expression of the PF identified by the SST gradient was further south by about one degree of latitude relative to the subsurface expression of the PF identified by the northern boundary of cold water.展开更多
Seasonal variability of the North Equatorial Current （NEC） transport in the western Pacific Ocean is investigated with ECMWF Ocean Analysis/Reanalysis System 3 （eRA-S3）. The result shows that NEC transport （NT） ...Seasonal variability of the North Equatorial Current （NEC） transport in the western Pacific Ocean is investigated with ECMWF Ocean Analysis/Reanalysis System 3 （eRA-S3）. The result shows that NEC transport （NT） across different longitudes in the research area shows a similar double-peak structure, with two maxima （in summer and winter）, and two minima （in spring and autumn）. This kind of structure can also be found in NEC geostrophic transport （NGT）, but in a different magnitude and phase. These differences are attributable to Ekman transport induced by the local meridional wind and transport caused by nonzero velocity at the reference level, which is assumed to be zero in the NGT calculation. In the present work, a linear vorticity equation governing a 1.5-layer reduced gravity model is adopted to examine the dynamics of the seasonal variability of NGT. It is found that the annual cycle of NGT is mainly controlled by Ekman pumping induced by local wind, and westward-propagating Rossby waves induced by remote wind. Further research demonstrates that the maximum in winter and minimum in spring are mostly attributed to wind east of the dateline, whilst the maximum in summer and minimum in autumn are largely attributed to that west of the dateline.展开更多
Based on the GDEM hydrographic data with a resolution of 0.5°× 0.5°, the current system (Kuroshio south of Japan and Kuroshio Extension east of Japan) is determined by using the P-Vector Method, and its...Based on the GDEM hydrographic data with a resolution of 0.5°× 0.5°, the current system (Kuroshio south of Japan and Kuroshio Extension east of Japan) is determined by using the P-Vector Method, and its seasonal variability is investigated. The Kuroshio Meander south of Japan, the two lee-wave meanders in the Kuroshio Extension and the bifurcation of the Kuroshio Extension are properly presented. The path of the Kuroshio Meander, the position of the second (east) meander in the Kuroshio Extension and the bifurcation of the Kuroshio Extension display evident seasonal variation.展开更多
The paper presents data on mean monthly discharges of nearly one hundred springs in Central Europe,measured over several years.Analyzes were based on discharge variability coefficients(V,M,Cv)and Markham’s seasonalit...The paper presents data on mean monthly discharges of nearly one hundred springs in Central Europe,measured over several years.Analyzes were based on discharge variability coefficients(V,M,Cv)and Markham’s seasonality parameters:seasonality index and time of concentration.The results were interpreted with reference to three basic types of hydrogeological outflows:karst,fissure and porous.Seasonal spring discharge was found to be correlated with the spring altitude.展开更多
Inland lakes in arid Central Asia are particularly susceptible to the impact of climate change and human activities.Ebinur Lake,the largest salt inland lake in Xinjiang,Northwest China,has experienced rapid shrinkage,...Inland lakes in arid Central Asia are particularly susceptible to the impact of climate change and human activities.Ebinur Lake,the largest salt inland lake in Xinjiang,Northwest China,has experienced rapid shrinkage,with human activities identified as the primary influencing factor.However,it remains unclear how human water use in different sectors,such as irrigation,husbandry,and industry,is responsible for the long-term change and seasonal variability of the lake area under changing climate.This study aims to address this knowledge gap by developing an integrated hydrological-socioeconomic-lake model that simulates the changes in the Ebinur Lake area during the period of 1950–2020.The simulated lake area changes under different model experiments were then compared with separate the impacts of climate change and human water use of different sectors.The results indicate that climate change,irrigation,husbandry,and industry water uses have contributed+5%,-79%,-25%,and-1%of the long-term change in the lake area,respectively.Despite climate change alone increasing the lake area,the increase in human water use has resulted in the persistent decline of Ebinur Lake.Notably,husbandry water use emerges as a significant contributor to lake shrinkage,accounting for approximately one-third of the impact of irrigation.Furthermore,irrigation water use has contributed to the enhanced seasonal variability,as indicated by the difference between the maximum and minimum monthly lake area in a year.This difference has increased from 120 km2in the 1950s to 183 km2in the 2010s.展开更多
Seasonal variations in tropical and subtropical convective and stratiform precipitation of the East Asian monsoon are analyzed using 10-year (1998-2007) Tropical Rainfall Measuring Mission (TRMM) precipitation radar (...Seasonal variations in tropical and subtropical convective and stratiform precipitation of the East Asian monsoon are analyzed using 10-year (1998-2007) Tropical Rainfall Measuring Mission (TRMM) precipitation radar (PR) rain products (2A25). Datasets from the Intergovernmental Panel on Climate Change Fourth Assessment Report (AR4) 24 general circulation models (GCMs) are evaluated using TRMM PR rain products in terms of their ability to simulate convective and stratiform precipitation and their deficiencies. The results show that Asian monsoon convective and stratiform precipitation increases significantly after onset of the summer monsoon, but the percentage of convective precipitation clearly decreases over tropical areas while it increases in subtropical regions. The GCMs simulate well the seasonal variation in the contribution of Asian monsoon subtropical convective precipitation to the total rainfall; however, the simulated convective precipitation amount is high while the simulated stratiform precipitation amount is low relative to TRMM measurements, especially over the Asian monsoon tropical region. There is simultaneous TRMM-observed convective and stratiform precipitation in space and time, but GCMs cannot simulate this relationship between convective and stratiform precipitation, resulting in the deficiency of stratiform precipitation simulations.展开更多
The seasonal variability of the significant wave height（SWH） in the South China Sea（SCS） is investigated using the most up-to-date gridded daily altimeter data for the period of September 2009 to August 2015. The ...The seasonal variability of the significant wave height（SWH） in the South China Sea（SCS） is investigated using the most up-to-date gridded daily altimeter data for the period of September 2009 to August 2015. The results indicate that the SWH shows a uniform seasonal variation in the whole SCS, with its maxima occurring in December/January and minima in May. Throughout the year, the SWH in the SCS is the largest around Luzon Strait（LS） and then gradually decreases southward across the basin. The surface wind speed has a similar seasonal variation, but with different spatial distributions in most months of the year. Further analysis indicates that the observed SWH variations are dominated by swell. The wind sea height, however, is much smaller. It is the the largest in two regions southwest of Taiwan Island and southeast of Vietnam Coast during the northeasterly monsoon, while the largest in the central/southern SCS during the southwesterly monsoon. The extreme wave condition also experiences a significant seasonal variation. In most regions of the northern and central SCS, the maxima of the 99 th percentile SWH that are larger than the SWH theoretically calculated with the wind speed for the fully developed seas mainly appear in August–November, closely related to strong tropical cyclone activities.Compared with previous studies, it is also implied that the wave climate in the Pacific Ocean plays an important role in the wave climate variations in the SCS.展开更多
The objective of this study is to model the mean and seasonal mass transportof the Pacific to Indian O-cean throughflow using variable-grid global Ocean General CirculationModel (OGCM) with fine grid (1°/6) cover...The objective of this study is to model the mean and seasonal mass transportof the Pacific to Indian O-cean throughflow using variable-grid global Ocean General CirculationModel (OGCM) with fine grid (1°/6) covering the area from 20°S to 60°N and from 98°E to 156°E.The computations show that Indonesian Throughflow (ITF) mass transport, computed as a sum ofthrough-strait transport, has maximum transport in Sept. (17. 5Sv) and minimum transport in Jan. (9.5Sv). The annual mean ITF transport amounts to 14. 5Sv. Twenty-two percent of this transport passesthrough Lombok Strait. Sixty-five percent of this transport passes through Timor Passage.Semi-annual variability is apparent in Lombok and Ombai Straits while annual variability is apparentin Timor Passage.展开更多
The seasonal variability of cirrus depolarization ratio and its altitude at the region of Beijing （39.93°N, 116.43°E, the capital of China） are presented. From the results obtained from the cloud aerosol l...The seasonal variability of cirrus depolarization ratio and its altitude at the region of Beijing （39.93°N, 116.43°E, the capital of China） are presented. From the results obtained from the cloud aerosol lidar and infrared pathfinder satellite observations lidar measurements, it appears that the values of depolarization ratio and altitude of cirrus are generally higher in autumn and summer than those in spring and winter, and the cirrus altitude is modulated by the height of tropopause. Additionally, the depolarization ratio tends to linearly vary with the increase of altitude and the decrease of temperature.展开更多
Here we used Empirical Mode Decomposition （EMD） method to study seasonal variability and nonlinear trend of corrected AERONET Aerosol Optical Depth （AOD/Hi） and corrected PM10 mass concentrations （PMmxf（RH）） i...Here we used Empirical Mode Decomposition （EMD） method to study seasonal variability and nonlinear trend of corrected AERONET Aerosol Optical Depth （AOD/Hi） and corrected PM10 mass concentrations （PMmxf（RH）） in Hong Kong during 2005-2011. AODPrli is highly correlated with PMI0xf（RH） in semi-annual and annual time scales （with correlation coefficient 0.67 for semi-annual and 0.79 for annual components, 95% confidence interval）. On the semi-annual scale, both AOD/Hi and PM10xf（RH） can capture the two maxima in March and October, respectively, with much stronger amplitude in March proba- bly due to the long-range transport of dust storm. On the annual cycle, the AOD/Hi and PMI0xf（RH）, which are negatively correlated with the precipitation and solar radiation, vary coherently with the maxima in February. This annual peak occurs about one month earlier than the first peak of the semi-annual variability in March, but with only half amplitude. During 2005-2011, both AOD/Hi and PM10xf（RH） exhibit the pronounced decreasing trend with the mean rate of 14 gg m-3 per year for PM10xf（RH）, which reflects the significant effects of the air pollution control policy in Hong Kong during the past decade. The nonlinear trend analysis indicates that the decreasing of PM10xf（RH） is slower than that of AOD/Hi when the AOD/Hi is less than 0.44 but becomes faster when the AOD/Hi exceeds 0.44. These results illustrate that the AERONET AOD can be used quantitatively to estimate local air-quality variability on the semi-annual, annual, and long-term trend time scales.展开更多
Seasonal variability of the bifurcation of the North Equatorial Current （NEC） is studied by constructing the analytic solu- tion for the time-dependent horizontal linear shallow water quasi-geostrophic equations. Us...Seasonal variability of the bifurcation of the North Equatorial Current （NEC） is studied by constructing the analytic solu- tion for the time-dependent horizontal linear shallow water quasi-geostrophic equations. Using the Florida State University wind data from 1961 through 1992, we find that the bifurcation latitude of the NEC changes with seasons. Furthermore, it is shown that the NEC bifurcation is at its southernmost latitude （12.7°N） in June and the northernmost latitude （14.4~ N） in November.展开更多
基金The National Natural Science Foundations of China under contract Nos40406009,40333030and40706013
文摘The muhiyear averaged surface current field and seasonal variability in the Kuroshio and adjacent regions are studied. The data used are trajectories and （1/4） ° latitude by （1/4） ° longitude mean currents derived from 323 Argos drifters deployed by Chinese institutions and world ocean circulation experiment from 1979 to 2003. The results show that the Kuroshio surface path adapts well to the western boundary topography and exhibits six great turnings. The branching occurs frequently near anticyclonic turnings rather than near cyclonic ones. In the Luzon Strait, the surface water intrusion into the South China Sea occurs only in fall and winter. The Kuroshio surface path east of Taiwan, China appears nearly as straight lines in summer, fall, and winter, when anticyclonic eddies coexist on its right side; while the path may cyclonically turning in spring when no eddy exists. The Kuroshio intrusion northeast of Taiwan often occurs in fall and winter, but not in summer. The running direction, width and velocity of the middle segment of the Kuroshio surface currents in the East China Sea vary seasonally. The northward intrusion of the Kuroshio surface water southwest of Kyushu occurs in spring and fall, but not in summer. The northmost position of the Kuroshio surface path southwest of Kyushu occurs in fall, but never goes beyond 31 °N. The northward surface current east of the Ryukyu Islands exists only along Okinawa-Amami Islands from spring to fall. In particular, it appears as an arm of an anti- cyclonic eddy in fall.
基金Supported by the National Basic Research Program of China (973Program) (No. 2010CB950300)the Knowledge Innovation Program of Chinese Academy of Sciences (No. KZCX2-YW-Q11-02)+1 种基金the Knowledge Innovation Program of Chinese Academy of Sciences(No. KZCX2-YW-BR-04)the National Basic Research Program of China (973 Program) (No. 2012CB955603)
文摘Based on HYbrid Coordinate Ocean Model (HYCOM) assimilation and observations, we analyzed seasonal variability of the salinity budget in the southeastern Arabian Sea (AS) and the southern part of the Bay of Bengal (BOB), as well as water exchange between the two basins. Results show that fresh water flux cannot explain salinity changes in salinity budget of both regions. Oceanic advection decreases salinity in the southeastern AS during the winter monsoon season and increases salinity in the southern BOB during the summer monsoon season. In winter, the Northeast Monsoon Current (NMC) carries fresher water from the BOB westward into the southern AS; this westward advection is confined to 4°-6°N and the upper 180 m south of the Indian peninsula. Part of the less saline water then turns northward, decreasing salinity in the southeastern AS. In summer, the Southwest Monsoon Current (SMC) advects high-salinity water from the AS eastward into the BOB, increasing salinity along its path. This eastward advection of high-salinity water south of the India Peninsula extends southward to 2°N, and the layer becomes shallower than in winter. In addition to the monsoon current, the salinity difference between the two basins is important for salinity advection.
基金Supported by the National Natural Science Foundation of China(No.41776012)the Key R&D Project of Zhejiang Province(No.2020C03012)+4 种基金the Shandong Provincial Natural Science Foundation(No.ZR2020MD059)the Key R&D Project of Guangdong Province(No.2020B1111030002)the Major Science and Technology Project of Sanya YZBSTC(No.SKJC-KJ-2019KY03)the National Key R&D Program of China(No.2019YFD0901305)the Marine Science and Technology Project of North China Sea Bureau in 2020:Tempo-Spatial Distribution and Its Mechanisms of the Bottom Oxygen-Poor Zones in the Bohai Sea(No.202001)。
文摘Deoxygenation has frequently appeared in coastal ecosystems over the past century due to the joint infl uence of increasing anthropogenically induced nutrient inputs and global warming.The semi-enclosed Bohai Sea is a typical system that is prone to deoxygenation,with regular hypoxia events consistently recorded in recent decades.Based on in-situ observation data collected in large-scale voyage surveys in the Bohai Sea during 2008-2017,the seasonal variability in dissolved oxygen(DO)and its controlling mechanisms were studied.The results indicated that in spring and autumn,the DO distributions exhibited similar spatial patterns in the surface and bottom layers,while in summer,its spatial distribution was characterized by large-scale oxygen-poor zones distributed off the Qinhuangdao Coast and the central southern Bohai Sea in the bottom layer.The controlling mechanisms of the DO distribution varied from season to season.Spring and autumn DO distributions were dominated by the seawater temperature.Under the combined eff ects of stratifi cation and decomposition,the summer bottom DO exhibited dual-core distribution.On the one hand,stratifi cation could greatly impede vertical mixing,resulting in reduced bottom DO replenishment.On the other hand,the increased bottom organic matter intensifi ed the decomposition processes,inducing massive DO consumption and elevated dissolved inorganic nitrogen concentrations.In addition,the stronger stratifi cation might be the reason for the more severe deoxygenation in the southern oxygen-poor zones in summer.Our study provides guidance for an in-depth understanding of the DO seasonality in the Bohai Sea and the mechanisms that modulate it and for the improvement of hypoxia forecasts in ocean models.
基金This study was supported by the National Natural Science Foundation of China under contract Nos 40676007, 40576019 and 40576012 the Key Laboratory of Tropical Marine and Enrironmant Dynamics open project.
文摘The seasonal variability of tropical cyclones （CTCs） generated over the South China Sea （SCS） from 1948 to 2003 is analyzed. It peaks in occurrence in August and few generate in late winter （from January to March）. The seasonal activity is attributed to the variability of atmosphere and ocean environments associated with the monsoon system. It is found that the monsoonal characteristics of the SCS basically determine the region of tropical cyclone （TC） genesis in each month.
基金The National Basic Research Program(973 Program)of China under contract No.2012CB417402the CAS Strategy Pioneering Program under contract No.XDA10020104+1 种基金the Global Change and Air–Sea Interaction under contract No.GASI-03-01-01-02the National Natural Science Foundation of China under contract No.41406012
文摘Using the 28℃ isotherm to define the Western Pacific Warm Pool （WPWP）, this study analyzes the seasonal variability of the WPWP thermohaline structure on the basis of the monthly-averaged sea temperature and salinity data from 1950 to 2011, and the dynamic and thermodynamic mechanisms based on the monthly-averaged wind, precipitation, net heat fluxes and current velocity data. A△T=-0.4℃ is more suitable than other temperature criterion for determining the mixed layer （ML） and barrier layer （BL） over the WPWP using monthly-averaged temperature and salinity data. The WPWP has a particular thermohaline structure and can be vertically divided into three layers, i.e., the ML, BL, and deep layer （DL）. The BL thickness （BLT） is the thickest, while the ML thickness （MLT） is the thinnest. The MLT has a similar seasonal variation to the DL thickness （DLT） and BLT. They are all thicker in spring and fall but thinner in summer. The temperatures of the ML and BL are both higher in spring and autumn but lower in winter and summer with an annual amplitude of 0.15℃, while the temperature of the DL is higher in May and lower in August. The averaged salinities at these three layers are all higher in March but lower in September, with annual ranges of 0.41-0.45. Zonal currents, i.e., the South Equatorial Current （SEC） and North Equatorial Counter Current （NECC）, and winds may be the main dynamic factors driving the seasonal variability in the WPWP thermohaline structure, while precipitation and net heat fluxes are both important thermodynamic factors. Higher （lower） winds cause both the MLT and BLT to thicken （thin）, a stronger （weaker） NECC induces MLT, BLT, and DLT to thin （thicken）, and a stronger （weaker） SEC causes both the MLT and BLT to thicken （thin） and the DLT to thin （thicken）. An increase （decrease） in the net heat fluxes causes the MLT and BLT to thicken （thin） but the DLT to thin （thicken）, while a stronger （weaker） precipitation favors thinner （thicker） MLT but thicker （thinner） BLT and DLT. In addition, a stronger （weaker） NECC and SEC cause the temperature of the three layers to decrease （increase）, while the seasonal variability in salinity at the ML, BL, and DL might be controlled by the subtropical cell （STC）.
基金Supported by the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDA05030402)the National Natural Science Foundation of China(Nos.U1406403,41121064,41376092)the Public Science and Technology Research Funds Projects of Ocean(No.200905012-9)
文摘The turbidity maximum zone(TMZ) is one of the most important regions in an estuary.However,the high concentration of suspended material makes it difficult to measure the partial pressure of CO_2(pCO_2) in these regions.Therefore,very little data is available on the pCO_2 levels in TMZs.To relatively accurately evaluate the CO_2 flux in an example estuary,we studied the TMZ and surrounding area in the Changjiang(Yangtze) River estuary.From seasonal cruises during February,August,November 2010,and May 2012,the pCO_2 in the TMZ and surrounding area was calculated from pH and total alkalinity(TA)measured in situ,from which the CO_2 flux was calculated.Overall,the TMZ and surrounding area acted as a source of atmosphere CO_2 in February and November,and as a sink in May and August.The average FCO_2was-9,-16,5,and 5 mmol/(m^2·d) in May,August,November,and February,respectively.The TMZ's role as a source or sink of atmosphere CO_2 was quite different to the outer estuary.In the TMZ and surrounding area,suspended matter,phytoplankton,and pH were the main factors controlling the FCO_2,but here the influence of temperature,salinity,and total alkalinity on the FCO_2 was weak.Organic carbon decomposition in suspended matter was the main reason for the region acting as a CO_2 source in winter,and phytoplankton production was the main reason the region was a CO_2 sink in summer.
基金This project was supported by the National Natural Science Foundation of China under contract No.49876009.
文摘A coupled ice-ocean isopycnal numerical model of the Southern Ocean is established tostudy the circulation and its seasonal variability in the region around the Kerguelen Plateau. An analysis of the simulated results shows significant stripe-like structure and non-zonal feature of the Antarctic Cir-cumpolar Current (ACC) in this region. ACC begins to bifurcate and to turn its direction before meeting the plateau. The southernmost branch of ACC is near to the Antarctic coast and displays its strong interaction with the westward Antarctic Slope Current. The northern branch of ACC has a tendency of annual variations while the southern one varies in a semiannual cycle. The variation phases of both branches are coincident with that of the wind stress in this region.
基金Supported by the National Natural Science Foundation of China(Nos.41776012,41606107,41576082)the National Key Research and Development Program of China(Nos.2019YFD0901305,2018YFC1407605)+4 种基金the Science and Technology Development Plan Project of Shandong Province(No.2016ZDJS09A02)the Key Research and Development Project of Zhejiang Province(No.2020C03012)the Key Research and Development Project of Guangdong Province(No.2020B1111030002)the Major Science and Technology Project of Sanya YZBSTC(No.YZ2019ZD0X)the Shandong Provincial Natural Science Foundation(No.ZR201911060280)。
文摘The chlorophyll a(Chl a)is an important indicator of marine ecosystems.The spatiotemporal variation of the Chl a greatly aff ects the mariculture and marine ranching in coastal waters of the Shandong Peninsula.In the current study,the climatology and seasonal variability of surface Chl-a concentration around the Shandong Peninsula are investigated based on 16 years(December 2002-November 2018)of satellite observations.The results indicate that the annual mean Chl-a concentration is greater in the Bohai Sea than in the Yellow Sea and decreases from coastal waters to off shore waters.The highest Chl-a concentrations are found in Laizhou Bay(4.2-8.0 mg/m^(3)),Haizhou Bay(4.2-5.9 mg/m^(3))and the northeast coast of the Shandong Peninsula(4.4-5.0 mg/m^(3)),resulting from the combined eff ects of the intense riverine input and long residence time caused by the concave shape of the coastline.The seasonal Chl-a concentration shows a significant spatial variation.The Chl-a concentrations in these three subregions generally exhibit an annual maximum in August/September,due to the combined eff ects of sea surface temperature,river discharge and sea surface wind.In the southeast coast region,however,the Chl-a concentration is lowest throughout the year and reaches a maximum in February with a minimum in July,forced by the seasonal evolution of the Yellow Sea Cold Water and monsoon winds.The interannual Chl-a concentration trends vary among regions and seasons.There are significant increasing trends over a large area around Haizhou Bay from winter to summer,which are mainly caused by the rising sea surface temperature and eutrophication.In other coastal areas,the Chl-a concentration shows decreasing trends,which are clearest in summer and induced by the weakening land rainfall.This study highlights the differences in the Chl-a dynamics among regions around the Shandong Peninsula and is helpful for further studies of coupled physical-ecological-human interactions at multiple scales.
基金The National Basic Research Program(973 Program)of China under contract Nos 2012CB956000 and 2011CB409803the National Natural Science Foundation of China under contract Nos 41475101,41421005,and 41276028+1 种基金the Natural Science Foundation of China-Shandong Joint Fund for Marine Science Research Centers under contract No.U1406401the Strategic Priority Project of Chinese Academy of Sciences under contract Nos XDA11010301 and XDA11020306
文摘As the spatio-temporal variability of the Kuroshio is highly influenced by mesoscale eddies, representing its seasonal variability characteristics requires sufficiently long term observations to reduce the uncertainties. Geostrophic velocity data estimated from hydrographic observation from 1987 to 2010 and the shipboard ADCP velocity data from 1993 to 2008 at the PN Section in the central East China Sea are collected to view the seasonal variability objectively. From both types of observation, it is found that the seasonal climatology mean of the Kuroshio Current exhibits significant difference in three areas, which are located at the Kuroshio Current core and its two flanks in a shallow layer less than 300 m, with the weakest northeast current at the core in autumn, the strongest counter current on the right flank in spring, and the strongest northeast current on the left flank in autumn, respectively. The seasonal variance of the Kuroshio Current also exhibits significant difference on the off- shore side of the Kuroshio, with larger variance in spring and summer while smaller variance in autumn and winter. For the current parallel to the PN Section, the ratio of the seasonal variability component to the intraseasonal variability component is relatively smaller than that for the current perpendicular to the PN Section. Further analyses indicate that the seasonal variability at the PN Section is tightly linked to the upstream and downstream current variability.
基金supported by the Chinese Polar Environment Comprehensive Investigation & Assessment Programs (Grant nos. CHINARE2012-2016 for 01-01-07, CHINARE2016-01-01, and CHINARE2016-04-01)the National Natural Science Foundation of China (Grant nos. 41306206 and U1406404)
文摘Four sections of expendable conductivity-temperature-depth （XCTD） profiles from Fremantle, Australia to Antarctic Zhongshan Station and Moderate Resolution Imaging Spectroradiometer-Aquarius （MODIS-A） sea surface temperature （SST） products were used to study the structure and seasonal variability of Southeast Indian Ocean fronts. Water mass analysis showed that surface water masses in the Southeast Indian Ocean were less salty in March than in November. Compared with November, the subtropical front （STF） moved southward about one degree of latitude in March, whereas seasonal variability of the subantarctic front （SAF） and polar front （PF） locations was not obvious. In March, the saline front moved northward about two degrees of latitude relative to the thermal front in the upper 100 m at the SAF, which was the northern boundary of sub- Antarctic surface water （SASW）. Analysis of climatological SST gradients from the satellite data showed that regions of enhanced sea surface temperature （SST） gradients were collocated with frontal locations identified with the XCTD data using water mass criteria. The surface expression of the PF identified by the SST gradient was further south by about one degree of latitude relative to the subsurface expression of the PF identified by the northern boundary of cold water.
基金Supported by the National Basic Research Program of China(973 Program)(Nos.2012CB417401,2013CB956202)the Major Project of National Natural Science Foundation of China(No.40890151)
文摘Seasonal variability of the North Equatorial Current （NEC） transport in the western Pacific Ocean is investigated with ECMWF Ocean Analysis/Reanalysis System 3 （eRA-S3）. The result shows that NEC transport （NT） across different longitudes in the research area shows a similar double-peak structure, with two maxima （in summer and winter）, and two minima （in spring and autumn）. This kind of structure can also be found in NEC geostrophic transport （NGT）, but in a different magnitude and phase. These differences are attributable to Ekman transport induced by the local meridional wind and transport caused by nonzero velocity at the reference level, which is assumed to be zero in the NGT calculation. In the present work, a linear vorticity equation governing a 1.5-layer reduced gravity model is adopted to examine the dynamics of the seasonal variability of NGT. It is found that the annual cycle of NGT is mainly controlled by Ekman pumping induced by local wind, and westward-propagating Rossby waves induced by remote wind. Further research demonstrates that the maximum in winter and minimum in spring are mostly attributed to wind east of the dateline, whilst the maximum in summer and minimum in autumn are largely attributed to that west of the dateline.
基金supported by the Ministry of Science and Technology of China under contract(Grant No.2002CCA00200)by the Ministry of Education of China under contract(Grant No.99075).
文摘Based on the GDEM hydrographic data with a resolution of 0.5°× 0.5°, the current system (Kuroshio south of Japan and Kuroshio Extension east of Japan) is determined by using the P-Vector Method, and its seasonal variability is investigated. The Kuroshio Meander south of Japan, the two lee-wave meanders in the Kuroshio Extension and the bifurcation of the Kuroshio Extension are properly presented. The path of the Kuroshio Meander, the position of the second (east) meander in the Kuroshio Extension and the bifurcation of the Kuroshio Extension display evident seasonal variation.
文摘The paper presents data on mean monthly discharges of nearly one hundred springs in Central Europe,measured over several years.Analyzes were based on discharge variability coefficients(V,M,Cv)and Markham’s seasonality parameters:seasonality index and time of concentration.The results were interpreted with reference to three basic types of hydrogeological outflows:karst,fissure and porous.Seasonal spring discharge was found to be correlated with the spring altitude.
基金supported by the Third Xinjiang Scientific Expedition and Research(Grant No.2021xjkk0805)the National Natural Science Foundation of China(Grant No.41790424)NSFC-DFG Mobility(Grant No.M0468)。
文摘Inland lakes in arid Central Asia are particularly susceptible to the impact of climate change and human activities.Ebinur Lake,the largest salt inland lake in Xinjiang,Northwest China,has experienced rapid shrinkage,with human activities identified as the primary influencing factor.However,it remains unclear how human water use in different sectors,such as irrigation,husbandry,and industry,is responsible for the long-term change and seasonal variability of the lake area under changing climate.This study aims to address this knowledge gap by developing an integrated hydrological-socioeconomic-lake model that simulates the changes in the Ebinur Lake area during the period of 1950–2020.The simulated lake area changes under different model experiments were then compared with separate the impacts of climate change and human water use of different sectors.The results indicate that climate change,irrigation,husbandry,and industry water uses have contributed+5%,-79%,-25%,and-1%of the long-term change in the lake area,respectively.Despite climate change alone increasing the lake area,the increase in human water use has resulted in the persistent decline of Ebinur Lake.Notably,husbandry water use emerges as a significant contributor to lake shrinkage,accounting for approximately one-third of the impact of irrigation.Furthermore,irrigation water use has contributed to the enhanced seasonal variability,as indicated by the difference between the maximum and minimum monthly lake area in a year.This difference has increased from 120 km2in the 1950s to 183 km2in the 2010s.
基金supported by National Natural Science Foundation of China (Grant No. 40428002)Scientific Research on Public Causes of China (Grant No. 2004 CB418303)
文摘Seasonal variations in tropical and subtropical convective and stratiform precipitation of the East Asian monsoon are analyzed using 10-year (1998-2007) Tropical Rainfall Measuring Mission (TRMM) precipitation radar (PR) rain products (2A25). Datasets from the Intergovernmental Panel on Climate Change Fourth Assessment Report (AR4) 24 general circulation models (GCMs) are evaluated using TRMM PR rain products in terms of their ability to simulate convective and stratiform precipitation and their deficiencies. The results show that Asian monsoon convective and stratiform precipitation increases significantly after onset of the summer monsoon, but the percentage of convective precipitation clearly decreases over tropical areas while it increases in subtropical regions. The GCMs simulate well the seasonal variation in the contribution of Asian monsoon subtropical convective precipitation to the total rainfall; however, the simulated convective precipitation amount is high while the simulated stratiform precipitation amount is low relative to TRMM measurements, especially over the Asian monsoon tropical region. There is simultaneous TRMM-observed convective and stratiform precipitation in space and time, but GCMs cannot simulate this relationship between convective and stratiform precipitation, resulting in the deficiency of stratiform precipitation simulations.
基金The Shandong Provincial Natural Science Foundation under contract Nos ZR2015DQ006 and ZR2014DQ005the National Natural Science Foundation of China under contract Nos 41506008 and 41476002the China Postdoctoral Science Foundation under contract No.2015M570609
文摘The seasonal variability of the significant wave height（SWH） in the South China Sea（SCS） is investigated using the most up-to-date gridded daily altimeter data for the period of September 2009 to August 2015. The results indicate that the SWH shows a uniform seasonal variation in the whole SCS, with its maxima occurring in December/January and minima in May. Throughout the year, the SWH in the SCS is the largest around Luzon Strait（LS） and then gradually decreases southward across the basin. The surface wind speed has a similar seasonal variation, but with different spatial distributions in most months of the year. Further analysis indicates that the observed SWH variations are dominated by swell. The wind sea height, however, is much smaller. It is the the largest in two regions southwest of Taiwan Island and southeast of Vietnam Coast during the northeasterly monsoon, while the largest in the central/southern SCS during the southwesterly monsoon. The extreme wave condition also experiences a significant seasonal variation. In most regions of the northern and central SCS, the maxima of the 99 th percentile SWH that are larger than the SWH theoretically calculated with the wind speed for the fully developed seas mainly appear in August–November, closely related to strong tropical cyclone activities.Compared with previous studies, it is also implied that the wave climate in the Pacific Ocean plays an important role in the wave climate variations in the SCS.
文摘The objective of this study is to model the mean and seasonal mass transportof the Pacific to Indian O-cean throughflow using variable-grid global Ocean General CirculationModel (OGCM) with fine grid (1°/6) covering the area from 20°S to 60°N and from 98°E to 156°E.The computations show that Indonesian Throughflow (ITF) mass transport, computed as a sum ofthrough-strait transport, has maximum transport in Sept. (17. 5Sv) and minimum transport in Jan. (9.5Sv). The annual mean ITF transport amounts to 14. 5Sv. Twenty-two percent of this transport passesthrough Lombok Strait. Sixty-five percent of this transport passes through Timor Passage.Semi-annual variability is apparent in Lombok and Ombai Straits while annual variability is apparentin Timor Passage.
基金supported by the National Natural Science Foundation of China under Grant No.40571097.
文摘The seasonal variability of cirrus depolarization ratio and its altitude at the region of Beijing （39.93°N, 116.43°E, the capital of China） are presented. From the results obtained from the cloud aerosol lidar and infrared pathfinder satellite observations lidar measurements, it appears that the values of depolarization ratio and altitude of cirrus are generally higher in autumn and summer than those in spring and winter, and the cirrus altitude is modulated by the height of tropopause. Additionally, the depolarization ratio tends to linearly vary with the increase of altitude and the decrease of temperature.
基金sponsored by the National Natural Science Foundation of China(Grant No.41206027)the China Postdoctoral Science Foundation(Grant No.2012M511460)+1 种基金the Key Laboratory of Global Change and Marine-Atmospheric Chemistry(Grant No.GCMAC1205)the Public Science and Technology Research Funds Projects of Ocean(Grant No.201105019)
文摘Here we used Empirical Mode Decomposition （EMD） method to study seasonal variability and nonlinear trend of corrected AERONET Aerosol Optical Depth （AOD/Hi） and corrected PM10 mass concentrations （PMmxf（RH）） in Hong Kong during 2005-2011. AODPrli is highly correlated with PMI0xf（RH） in semi-annual and annual time scales （with correlation coefficient 0.67 for semi-annual and 0.79 for annual components, 95% confidence interval）. On the semi-annual scale, both AOD/Hi and PM10xf（RH） can capture the two maxima in March and October, respectively, with much stronger amplitude in March proba- bly due to the long-range transport of dust storm. On the annual cycle, the AOD/Hi and PMI0xf（RH）, which are negatively correlated with the precipitation and solar radiation, vary coherently with the maxima in February. This annual peak occurs about one month earlier than the first peak of the semi-annual variability in March, but with only half amplitude. During 2005-2011, both AOD/Hi and PM10xf（RH） exhibit the pronounced decreasing trend with the mean rate of 14 gg m-3 per year for PM10xf（RH）, which reflects the significant effects of the air pollution control policy in Hong Kong during the past decade. The nonlinear trend analysis indicates that the decreasing of PM10xf（RH） is slower than that of AOD/Hi when the AOD/Hi is less than 0.44 but becomes faster when the AOD/Hi exceeds 0.44. These results illustrate that the AERONET AOD can be used quantitatively to estimate local air-quality variability on the semi-annual, annual, and long-term trend time scales.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 40890154, 40890153)the National Basic Research Development Program of China (973 Program, Grant No. 2005CB321700)
文摘Seasonal variability of the bifurcation of the North Equatorial Current （NEC） is studied by constructing the analytic solu- tion for the time-dependent horizontal linear shallow water quasi-geostrophic equations. Using the Florida State University wind data from 1961 through 1992, we find that the bifurcation latitude of the NEC changes with seasons. Furthermore, it is shown that the NEC bifurcation is at its southernmost latitude （12.7°N） in June and the northernmost latitude （14.4~ N） in November.
