共查询到20条相似文献，搜索用时 46 毫秒
1.
The processes underlying the development of the Kuroshio large meanders that occurred in 1986 and 1989 are investigated using
a satellite SST data set and hydrographic data. In both processes visible on the satellite SST images, a round-shaped, lower
SST region with a diameter of about 200 km is found to the east of the Kuroshio small “trigger” meander (Solomon, 1978) until
the region became extinguished near theEnshu Nada. The lower SST region can be interpreted as an anti cyclonic eddy, mainly because of the existence of a warm water mass in
the subsurface layer of this region. The warm water mass is characterized by a constant temperature of 18–19°C, the maximum
thickness of which is about 400 m. The satellite images show that the eddy is closely related to the Kuroshio path transforming
into a shape like the letter “S”. This means that the eddy plays an important role in the development of the Kuroshio large
meander since this, too, tends to follow an “S”-shaped path. Added to this, the subsurface layer structure of the eddy is
similar to that of the warm water mass offShikoku. This similarity, together with the eddy behavior visible on the satellite SST images, implies that the examined eddy corresponds
to the warm water mass offShikoku. In other words, the warm water mass offShikoku can be advected near to theEnshu Nada when the Kuroshio large meander occurs. 相似文献
2.
3.
Seasonal evolution of surface mixed layer in the Northern Arabian Sea (NAS) between 17° N–20.5° N and 59° E-69° E was observed
by using Argo float daily data for about 9 months, from April 2002 through December 2002. Results showed that during April
- May mixed layer shoaled due to light winds, clear sky and intense solar insolation. Sea surface temperature (SST) rose by
2.3 °C and ocean gained an average of 99.8 Wm−2. Mixed layer reached maximum depth of about 71 m during June - September owing to strong winds and cloudy skies. Ocean gained
abnormally low ∼18 Wm−2 and SST dropped by 3.4 °C. During the inter monsoon period, October, mixed layer shoaled and maintained a depth of 20 to
30 m. November - December was accompanied by moderate winds, dropping of SST by 1.5 °C and ocean lost an average of 52.5 Wm−2. Mixed layer deepened gradually reaching a maximum of 62 m in December. Analysis of surface fluxes and winds suggested that
winds and fluxes are the dominating factors causing deepening of mixed layer during summer and winter monsoon periods respectively.
Relatively high correlation between MLD, net heat flux and wind speed revealed that short term variability of MLD coincided
well with short term variability of surface forcing. 相似文献
4.
Research and development of the New Generation Sea Surface Temperature for Open Ccean (NGSST-O) product and its demonstration operation 总被引：1，自引：0，他引：1
Futoki Sakaida Hiroshi Kawamura Shin Takahashi Teruhisa Shimada Yoshimi Kawai Kohtaro Hosoda Lei Guan 《Journal of Oceanography》2009,65(6):859-870
Real-time generation and distribution of the New Generation Sea Surface Temperature for Open Ocean (NGSST-O) product began
in September 2003 as a demonstration operation of the Global Ocean Data Assimilation Experiment (GODAE) High-Resolution Sea
Surface Temperature Pilot Project. Satellite sea surface temperature (SST) observations from infrared radiometers (AVHRR,
MODIS) and a microwave radiometer (AMSR-E) are objectively merged to generate the NGSST-O product, which is a quality-controlled,
cloud-free, high-spatial-resolution (0.05° gridded), wide-coverage (13–63° N, 116–166° E), daily SST digital map. The NGSST-O
demonstration operation system has been developed in cooperation with the Japanese Space Agency (JAXA) and has produced six
years of continuous data without gaps. Comparison to in situ SSTs measured by drifting buoys indicates that the root mean-square error of NGSST-O has been kept at approximately 0.9°C. 相似文献
5.
Variability of sea surface temperature and warm pool area in the South China Sea and its relationship to the western Pacific warm pool 总被引：1，自引：0，他引：1
Sea surface temperature (SST) data derived from satellite and in situ measurements are used to study the thermal variability
in the South China Sea (SCS). Time–frequency–energy distributions, periods of variability, and trends are computed by the
Hilbert–Huang transform method. The SST trend from 1982 to 2005 is 0.276°C per decade in the SCS which is higher than 0.144°C
per decade in the western Pacific warm pool (WPWP). The warm pool (SST ≥ 28°C) area in the SCS has increased by 0.20 × 106 km2 per decade. The SST and area of the warm pool in the SCS are strongly correlated, respectively, with the SST and area of
the WPWP with a time lag of 1 month, suggestive of a strong connection between these two warm pools. Once the annual cycle
is eliminated, decadal oscillations dominate the variability of SST and warm pool area in the SCS. 相似文献
6.
We executed investigations of Mediterranean lenses detection in the Atlantic using data recorded by buoys-profilers of the
“Argo” project (more than 11200 profiles). We investigate the region from 28° to 47° N and from 7° to 27° W for the period
from 2001 to 2010. From these data, we revealed “lenses profiles” with the salinity values exceeding 36 psu (2043 cases).
We demonstrate the allocation of Argo buoys in the area investigated and indicate their working periods; we also show the
periodicity of the “lenses profiles.” It was found out that the Argo buoys traced individual lenses and depicted correctly
their movements, the vertical scale of the eddy, its location in the depth, and the hydrological peculiarities of the lenses.
We estimated the number of lenses occurring in different periods and analyzed the interaction of the Argo buoy with the intrathermocline
lenses. The importance of these investigations for studying the Mediterranean water dynamics was pointed out. 相似文献
7.
Index and Composites of the Kuroshio Meander South of Japan 总被引：1，自引：0，他引：1
Nikolai Maximenko 《Journal of Oceanography》2002,58(5):639-649
Using the merged NOAA National Oceanographic Data Center (NODC)/Japan Oceanographic Data Center (JODC)/Marine Information
Research Center (MIRC) historical hydrographic dataset, a new Kuroshio large meander (LM) index is introduced. This index
helps to distinguish between the LM events and other types of Kuroshio Current (KC) variability south of Japan. Observations,
re-systematized according to the index, provide composite patterns of typical formation and decay of the LM. The patterns
reveal a remarkable similarity between individual LMs and support the deterministic rather than the stochastic model of LM
evolution on a time-scale of one year. A “trigger” meander (TM) occurs on composite maps six months prior to the LM formation
as a 1° latitude southward shift of the KC axis south of Kyushu. When propagating eastward along the coast of Japan, TM gradually
increases in area. In principal the emergence of LM takes only one month. East of TM and LM a remarkable onshore shift of
the KC is noticed, supplying the coastal region with warm water. Other warm anomalies are found on the warm side of KC next
to the propagating TM and in the larger warm eddy area southeast of Kyushu. Different LMs survive for different times and
decay in some months after KC “jumps” across the Izu Ridge. Changes of water properties on isopycnals in the interior of LM
can be roughly described by two-layer kinematics with an interface at σθ = 27 which suggests a strong inflow of deep Kuroshio waters into the LM core during the formation of the latter.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
8.
利用南极走航观测评估卫星遥感海表面温度 总被引：3，自引：1，他引：2
利用1989-2005年间南极走航观测的海表面温度,对目前3个主要的卫星反演的SST产品AVHRR(Advanced Very High Resolution Radiometer),TMI(TRMM Microwave Imager)和AMSR-E(Advanced Microwave Scanning Radiometer for the Earth Observing System)进行了较为系统的评估,并着重检验了它们在南大洋的准确性.结果表明,AVHRR SST比观测数据偏冷,白天的偏差为-0.12℃,夜晚的偏差为-0.04℃,而且南大洋的冷偏差更为显著.TMI SST比观测数据明显偏暖,白天的偏差为0.48℃,夜晚的偏差为0.57℃,其温差ΔT受37GHz风速影响,在强风速(>6m/s)下这种影响仍然存在.AMSR-ESST比观测数据偏暖,白天的偏差为0.34℃,夜晚的偏差为0.27℃,而且南大洋的暖偏差相对较大.AMSR-E SST温差受水汽影响,并在南大洋随着水汽的增加而增加.通过进一步比较微波(AMSR-E和TMI)和红外(AVHRR)遥感的SST在2004年北半球冬季(即南半球夏季)的差别,发现微波遥感在热带(15°S-15°N)和南大洋区域(45°S以南)比红外遥感偏暖,而且在南大洋区域的偏差相对较大,相反在北半球中纬度区域(15°~40°N)偏冷.AMSR-E与AVHRR SST的温差,从白天到夜晚有减小的趋势,而TMI与AVHRR SST的温差无明显的变化. 相似文献
9.
The sea surface temperature(SST) seasonal cycle in the eastern equatorial Pacific(EEP) plays an important role in the El Ni?o–Southern Oscillation(ENSO) phenomenon. However, the reasonable simulation of SST seasonal cycle in the EEP is still a challenge for climate models. In this paper, we evaluated the performance of 17 CMIP6 climate models in simulating the seasonal cycle in the EEP and compared them with 43 CMIP5 climate models. In general, only CESM2 and SAM0-UNICON are able to successfully capture the annual mean SST characteristics,and the results showed that CMIP6 models have no fundamental improvement in the model annual mean bias.For the seasonal cycle, 14 out of 17 climate models are able to represent the major characteristics of the observed SST annual evolution. In spring, 12 models capture the 1–2 months leading the eastern equatorial Pacific region 1(EP1; 5°S–5°N, 110°–85°W) against the eastern equatorial Pacific region 2(EP2; 5°S–5°N, 140°–110°W). In autumn,only two models, GISS-E2-G and SAM0-UNICON, correctly show that the EP1 and EP2 SSTs vary in phase. For the CMIP6 MME SST simulation in EP1, both the cold bias along the equator in the warm phase and the warm bias in the cold phase lead to a weaker annual SST cycle in the CGCMs, which is similar to the CMIP5 results. However,both the seasonal cold bias and warm bias are considerably decreased for CMIP6, which leads the annual SST cycle to more closely reflect the observation. For the CMIP6 MME SST simulation in EP2, the amplitude is similar to the observed value due to the quasi-constant cold bias throughout the year, although the cold bias is clearly improved after August compared with CMIP5 models. Overall, although SAM0-UNICON successfully captured the seasonal cycle characteristics in the EEP and the improvement from CMIP5 to CMIP6 in simulating EEP SST is clear, the fundamental climate models simulated biases still exist. 相似文献
10.
The Princeton Ocean Model with realistic bottom topography has been used to investigate the summer temperature decrease in
the past 25 years in Fukuoka Bay. The vertical mixing of the model is expressed by a scheme that effectively includes the
influences of interannual variations of tidal currents and wind. The results show that the historical temperature decrease
in summer has been caused by tidal currents and wind weakening in the past 25 years in Fukuoka Bay. The weakening of tidal
currents and wind gives rise to weakening of the vertical mixing, and to enhancement of the estuarine circulation in the bay.
The enhancement of the estuarine circulation activates the inflow of open-ocean water toward Fukuoka Bay. Coastal water in
summer has therefore tended to be colder and more saline in the past 25 years. This interannual variation in coastal waters
is called “open-oceanization” in this study. On the basis of the numerical model, it is anticipated that the temperature will
decrease by 0.2°C in the next 25 years in Fukuoka Bay if the tide and wind weaken persistently as in the present bay. 相似文献
11.
The underwater vocalizations of the beluga whale summering in Onega Bay (64°24′N, 35°49′E) were recorded in June–July of 2008.
The vocalizations were classified into five major whistle types, four types of pulsed tones, click series, and noise vocalizations.
To determine the relationship between the behavioral activity and the underwater vocalizations, a total of fifty-one 2 minute-long
samples of the audio records were analyzed in the next six behavioral contexts: directional movements, quiet swimming, resting,
social interactions, individual hunting behavior, and the exploration of hydrophones by beluga whales. The overall vocalization
rate and the percentage of the main types of signals depend on the behavior of the belugas. We suggest that one of the whistle
types (the “stereotype whistle”) is used by belugas for long-distance communications, while other whistle types (with the
exception of “squeaks”) and three types of pulsed tones (with the exception of “vowels”) are used for short distance communication.
The percentage of “squeaks” and “vowels” was equally high in all the behavioral situations. Thus, we assume that “squeaks”
are contact signals. “Vowels” have a specific physical structure and probably play a role in identification signals. A high
rate of the click series was observed in the process of social interactions. 相似文献
12.
Kohtaro Hosoda Hiroshi Murakami Akira Shibata Futoki Sakaida Hiroshi Kawamura 《Journal of Oceanography》2006,62(3):339-350
This study compares infrared and microwave measurements of sea surface temperature (SST) obtained by a single satellite. The
simultaneous observation from the Global Imager (GLI: infrared) and the Advanced Microwave Scanning Radiometer (AMSR: microwave)
aboard the Advanced Earth Observing Satellite-II (ADEOS-II) provided an opportunity for the intercomparison. The GLI-and AMSR-derived
SSTs from April to October 2003 are analyzed with other ancillary data including surface wind speed and water vapor retrieved
by AMSR and SeaWinds on ADEOS-II. We found no measurable bias (defined as GLI minus AMSR), while the standard deviation of
difference is less than 1°C. In low water vapor conditions, the GLI SST has a positive bias less than 0.2°C, and in high water
vapor conditions, it has a negative (positive) bias during the daytime (nighttime). The low spatial resolution of AMSR is
another factor underlying the geographical distribution of the differences. The cloud detection problem in the GLI algorithm
also affects the difference. The large differences in high-latitude region during the nighttime might be due to the GLI cloud-detection
algorithm. AMSR SST has a negative bias during the daytime with low wind speed (less than 7 ms−1), which might be related to the correction for surface wind effects in the AMSR SST algorithm. 相似文献
13.
The Sea Surface Temperatures (SST) and currents are simulated over the north Indian Ocean, during the onset phase of southwest monsoon for the three years 1994, 1995, and 1996, using daily Special Sensor Microwave/Imager (SSM/I) winds and National Center for Environmental Prediction (NCEP) heat fluxes as forcings in the 2½ layer thermodynamic numerical ocean model. The results are discussed for the 30-day period from 16 May to 13 June for all the three years, to determine the ocean state during the onset phase of SW monsoon. The maximum variability in the simulated SST is found along the Somali coast, Indian coasts, and equatorial regions. The maximum SST in the North Arabian Sea is found to be greater than 30°C and minimum SST in the west equatorial region is 25°C during the onset phase of all three years. Model SSTs are in agreement with Reynolds SST. SST gradients in the north-south as well as in the east-west directions, west of 80°E are found to change significantly prior to the onset. It can be inferred from the study that the SST gradient of 2.5°C/2000 km is seen due north and due west of the region 2° - 7°S, 60° - 65°E, about 8 to 10 days prior to the arrival of SW monsoon near Kerala coast. Upper and lower layer circulation fields do not show prominent interannual variability. 相似文献
14.
Validation of GLI and other satellite-derived sea surface temperatures using data from the Rottnest Island ferry, Western Australia 总被引：3，自引：0，他引：3
An accurate platinum resistance thermometer (PRT) has been installed on a commercial ferry that operates between Hillarys
Marina, some 15 km north of Fremantle, and Rottnest Island off the Western Australian coast. The PRT is located in the engine
intake system and provides continuous under-way measurements of the bulk sea surface temperature (SST) at a depth of 1 m.
The “SeaFlyte” ferry makes the trip to Rottnest Island between 3 and 5 times daily and so a wealth of data is available for
comparison with the SST derived using data from the GLI instrument on ADEOS-II. Analyses of the ferry and satellite data confirm
the excellent quality of SST estimates from the GLI as well as four other satellite instruments—AVHRR on NOAA-16, AATSR on
ENVISAT, and the MODIS instruments on TERRA and AQUA. All satellite instruments showed a comparison standard deviation of
better than 0.6°C with GLI being better than 0.4°C. The number of ferry-satellite data coincidences used in this study demonstrates
one of the advantages of installing measurement systems on commercial ships that operate regular passenger or freight services
rather than infrequent deployments on research vessels. The analyses also demonstrate that satellite-derived SST estimates
obtained under low surface wind conditions must be treated with care. 相似文献
15.
Ship and satellite observations taken over the last thirty years show that mesoscale patterns of sea surface temperature (SST) in the California Current System are consistently found throughout the year and usually occur in approximately the same geographical locations. Typically, these patterns are more pronounced in fall/winter than in spring/summer. The temporal and spatial characteristics of these persistent feature were examined with satellite infrared (IR) measurements during winter 1980–1981. In January 1981, a ship surveyed the vertical structure of several physical, chemical, and biological parameters beneath one of these SST features centered near 32°N, 124°W. The surface IR pattern had a length scale of 200 km and a time scale of about 100 days. It disintegrated following the first two storms of the winter season. Motion studies of the pattern in late October indicated an anticyclonic rotation with maximum velocities of 50 cm s?1 at 50 km from the axis of rotation. As a unit, the pattern advected southward with an average speed of 1 cm s?1. Thermal fronts, determined from the satellite imagery, were strongest (0.4°C km?1) along the rim of the pattern and were advected anticyclonically with the pattern; their length scales were 20–30 km in the along-front direction and less than 10 km wide. The hydrographic data revealed a three-layer structure beneath the surface pattern; a 75 m deep surface layer, a cold-core region from 75 to 200 m depth, and a warm-core eddy extending from 250 to 1450 m. The anticyclonic motion of the surface layer was caused by a geostrophic adjustment to the surface dynamic height anomaly produced by the subsurface warm-core eddy. The IR pattern observed from space reflects the horizontal structure of the surface layer and is consistent with a theoretical model of a mean horizontal SST gradient perturbed by a subsurface density anomaly. Ship of opportunity SST observations collected by the National Marine Fisheries are shown to resolve mesoscale patterns. For December 1980, the SST pattern near 32°N, 124°W represented a 2°C warm anomaly compared with the 20-year mean monthly SST pattern. 相似文献
16.
Three ARGOS drift buoys were deployed in the Oyashio Current off the Kuril Islands near 45°N in fall, 1990, during a joint
Russia/Canada study of western boundary current dynamics in the Subarctic Pacific Ocean. We here report on one buoy deployed
within an anticyclonic warm core ring (WCR86B) which shows evidence of large amplitude inertial motions of near-diurnal frequency.
During its first week within the ring the buoy drifted with a mean azimuthal current speed of 0.40–0.45 m s−1 and a radius of rotation of 15–20 km. However, superimposed on the mean rotation of the ring at this time were “loops” of
near-diurnal period, radius 7–8 km and speeds exceeding 1 m s−1. During successive rotations the buoy spiraled outward, its mean period of rotation increased and the amplitude of the near-diurnal
motions decreased. The large motions are explained by inertial wave trapping and amplification within the extremely large
and weakly stratified eddy, wherein the negative vorticity of the eddy reduces the local inertial frequency to near-diurnal
frequency. We here suggest that either tidal or wind forcing may generate these high-amplitude “loop” motions.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
17.
Using the air-sea data set of January, 1983 (the mature phase of the 1982/83 El Nino event), the net radiation on the sea surface, the fluxes of the latent and the sensible heat from ocean to the atmosphere and the net heat gain of the sea surface are calculated over the Indian and the Pacific Oceans for the domain of 35°N-35°S and 45°E-75°W. The results indicate that the upward transfer of the latent and the sensible heat fluxes over the winter hemisphere is larger than that over the summer hemisphere. The sensible heat over the tropical mid Pacific in the Southern Hemisphere is transported from the atmosphere to the ocean, though its magnitude is rather small. The latent heat flux gained by the air over the eastern Pacific is less than the mean value of the normal year. The net radiation, on which the cloud amount has considerable impact, is essentially zonally distributed. Moreover, the sea surface temperature (SST) has a very good correlation with the net radiation, the region of warm SST coinci 相似文献
18.
A global eddy-permitting ocean-ice coupled model with a horizontal resolution of 0.25 by 0.25 is established on the basis of Modular Ocean Model version 4 (MOM4) and Sea Ice Simulator (SIS). Simulation results are compared with those of an intermediate resolution ocean-ice coupled model with a horizontal resolution of about 1 by 1 . The results show that the simulated ocean temperature, ocean current and sea ice concentration from the eddy-permitting model are better than those from the intermediate resolution model. However, both the two models have the common problem of ocean general circulation models (OGCMs) that the majority of the simulated summer sea surface temperature (SST) is too warm while the majority of the simulated subsurface summer temperature is too cold. Further numerical experiments show that this problem can be alleviated by incorporating the non-breaking surface wave-induced vertical mixing into the vertical mixing scheme for both eddy-permitting and intermediate resolution models. 相似文献
19.
A repeat hydrographic section has been maintained over two decades along the 180° meridian across the subarctic-subtropical
transition region. The section is naturally divided into at least three distinct zones. In the Subarctic Zone north of 46°N,
the permanent halocline dominates the density stratification, supporting a subsurface temperature minimum (STM). The Subarctic
Frontal Zone (SFZ) between 42°–46°N is the region where the subarctic halocline outcrops. To the south is the Subtropical
Zone, where the permanent thermocline dominates the density stratification, containing a pycnostad of North Pacific Central
Mode Water (CMW). The STM water colder than 4°C in the Subarctic Zone is originated in the winter mixed layer of the Bering
Sea. The temporal variation of its core temperature lags 12–16 months behind the variations of both the winter sea surface
temperature (SST) and the summer STM temperature in the Bering Sea, suggesting that the thermal anomalies imposed on the STM
water by wintertime air-sea interaction in the Bering Sea spread over the western subarctic gyre, reaching the 180° meridian
within a year or so. The CMW in this section originates in the winter mixed layer near the northern edge of the Subtropical
Zone between 160°E and 180°. The CMW properties changed abruptly from 1988 to 1989; its temperature and salinity increased
and its potential density decreased. It is argued that these changes were caused by the climate regime shift in 1988/1989
characterized by weakening of the Aleutian Low and the westerlies and increase in the SST in the subarctic-subtropical transition
region.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
20.
The origins and evolutions of two anticyclonic eddies in the northeastern South China Sea (SCS) were examined using multi-satellite
remote sensing data, trajectory data of surface drifting buoys, and in-situ hydrographic data during winter 2003/2004. The results showed that buoy 22918 tracked an anti-cyclonic warm-core eddy (AE1)
for about 20 days (December 4–23, 2003) in the northeastern SCS, and then escaped from AE1 eventually. Subsequently to that,
buoy 22517 remained within a different anti-cyclonic warm-core eddy (AE2) for about 78 days (from January 28 to April 14,
2004) in the same area. It drifted southwestward for about 540 km, and finally entered into the so-called “Luzon Gyre”. Using
inference from sea level anomaly (SLA), sea surface temperature (SST), geostrophic currents and the buoys’ trajectories, it
is shown that both eddies propagated southwestward along the continental slope of the northern SCS. The mean speeds of AE1
and AE2 movements were 9.7 cm/s and 10.5 cm/s, respectively, which are similar to the phase speed of Rossby waves in the northern
SCS. The variation of instantaneous speeds of the eddy movement and intensity of anticyclonic eddy may suggest complex interactions
between an anticyclonic eddy and its ambient fluids in the northern SCS, where the eddy propagated southwestward with Rossby
waves. Furthermore, SLA and SST images in combination with the temperature and salinity profiles obtained during a cruise
suggested that AE1 was generated in the interior SCS and AE2 was shed from the “Kuroshio meander”. 相似文献