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1.
The standard deviation of the central Pacific sea surface temperature anomaly (SSTA) during the period from October to February shows that the central Pacific SSTA variation is primarily due to the occurrence of the Central Pacific El Nio (CP-El Nio) and has a connection with the subtropical air-sea interaction in the northeastern Pacific. After removing the influence of the Eastern Pacific El Nio, an S-EOF analysis is conducted and the leading mode shows a clear seasonal SSTA evolving from the subtropical northeastern Pacific to the tropical central Pacific with a quasi-biennial period. The initial subtropical SSTA is generated by the wind speed decrease and surface heat flux increase due to a north Pacific anomalous cyclone. Such subtropical SSTA can further influence the establishment of the SSTA in the tropical central Pacific via the wind-evaporation-SST (WES) feedback. After established, the central equatorial Pacific SSTA can be strengthened by the zonal advective feedback and thermocline feedback, and develop into CP-El Nio. However, as the thermocline feedback increases the SSTA cooling after the mature phase, the heat flux loss and the re-versed zonal advective feedback can cause the phase transition of CP-El Nio. Along with the wind stress variability, the recharge (discharge) process occurs in the central (eastern) equatorial Pacific and such a process causes the phase consistency between the thermocline depth and SST anomalies, which presents a contrast to the original recharge/discharge theory.  相似文献   

2.
Based on an empirical orthogonal function (EOF) analysis of the monthly NCEP Optimum Interpolation Sea Surface Temperature (OISST) data in the South China Sea (SCS) after removing the climatological mean and trends of SST,over the period of January 1982 to October 2003,the corresponding TCF correlates best with the Dipole Mode Index (DMI),Nio1+2,Nio3.4,Nio3,and Nio4 indices with time lags of 10,3,6,5,and 6 months,respectively.Thus,a statistical hindcasts in the prediction model are based on a canonical correlation analysis (CCA) model using the above indices as predictors spanning from 1993/1994 to 2003/2004 with a 1-12 month lead time after the canonical variants are calculated,using data from the training periods from January 1982 to December1992.The forecast model is successful and steady when the lead times are 1-12 months.The SCS warm event in 1998 was successfully predicted with lead times from 1-12 months irrespective of the strength or time extent.The prediction ability for SSTA is lower during weak ENSO years,in which other local factors should be also considered as local effects play a relatively important role in these years.We designed the two forecast models:one using both DMI and Nio indices and the other using only Nio indices without DMI,and compared the forecast accuracies of the two cases.The spatial distributions of forecast accuracies show different confidence areas.By turning off the DMI,the forecast accuracy is lower in the coastal areas off the Philippines in the SCS,suggesting some teleconnection may occur with the Indian Ocean in this area.The highest forecast accuracies occur when the forecast interval is five months long without using the DMI,while using both of Nio indices and DMI,the highest accuracies occur when the forecast interval time is eight months,suggesting that the Nio indices dominate the interannual variability of SST anomalies in the SCS.Meanwhile the forecast accuracy is evaluated over an independent test period of more than 11 years (1993/94 to October 2004) by comparing the model performance with a simple prediction strategy involving the persistence of sea surface temperature anomalies over a 1-12 month lead time (the persisted prediction).Predictions based on the CCA model show a significant improvement over the persisted prediction,especially with an increased lead time (longer than 3 months).The forecast model performs steadily and the forecast accuracy,i.e.,the correlation coefficients between the observed and predicted SSTA in the SCS are about 0.5 in most middle and southern SCS areas,when the thresholds are greater than the 95% confidence level.For all 1 to 12 month lead time forecasts,the root mean square errors have a standard deviation of about 0.2.The seasonal differences in the prediction performance for the 1-12 month lead time are also examined.  相似文献   

3.
Coral bleaching, caused by elevated sea surface temperature(SST), is occurring more frequently and seriously worldwide. Due to the lack of field observations, we understand little about the large-scale variability of thermal stress in the South China Sea(SCS) and its effect on China’s coral reefs. This paper used 4-km high resolution gap-filled SST(Filled SST) data and thermal stress data related to coral bleaching derived from Coral Reef Temperature Anomaly Database(Co RTAD) to quantify the spatial and temporal characteristics of chronic thermal stress and acute thermal stress to China’s coral reefs in SCS from 1982 to 2009. We analyzed the trend of SST in summer and the thermal stress frequency, intensity and duration during this period. The results indicate that, as a chronic thermal stress, summer mean SST in SCS shows an average upward trend of 0.2℃/decade and the spatial pattern is heterogeneous. Waters of Xisha Islands and Dongsha Islands of the northern SCS are warming faster through time compared to Zhongsha Islands and Nansha Islands sea areas of the southern SCS. High frequency bleaching related thermal stress events for these reefs are seen in the area to the northwest of Luzon Island. Severe anomaly thermal stress events are more likely to occur during the subsequent year of the El Nino year for these coral reefs. Besides, the duration of thermal stress varies considerably by anomaly year and by region.  相似文献   

4.
By analyzing the variability of global SST(sea surface temperature) anomalies,we propose a unified Ni o index using the surface thermal centroid anomaly of the region along the Pacific equator embraced by the 0.7°C contour line of the standard deviation of the SST anomalies and try to unify the traditional Ni o regions into a single entity.The unified Ni o region covers almost all of the traditional Ni o regions.The anomaly time series of the averaged SST over this region are closely correlated to historical Ni o indices.The anomaly time series of the zonal and meridional thermal centroid have close correlation with historical TNI(Trans-Ni o index) indices,showing differences among El Ni o(La Ni a) events.The meridional centroid anomaly suggests that areas of maximum temperature anomaly are moving meridionally(although slightly) with synchronous zonal movement.The zonal centroid anomalies of the unified Ni o region are found helpful in the classification of the Eastern Pacific(EP)/Central Pacific(CP) types of El Ni o events.More importantly,the zonal centroid anomaly shows that warm areas might move during a single warming/cooling phase.All the current Ni o indices can be well represented by a simple linear combination of unified Ni o indices,which suggests that the thermal anomaly(SSTA) and thermal centroid location anomaly of the unified Ni o region would yield a more complete image of each El Ni o/ La Ni a event.  相似文献   

5.
The responses of Sea Surface Temperature(SST) to greenhouse gas(GHG) and anthropogenic aerosol in the North Pa- cific are compared based on the historical single and all-forcing simulations with Geophysical Fluid Dynamics Laboratory Climate Model version 3(GFDL CM3). During 1860–2005, the effect of GHG forcing on the North Pacific SST is opposite to that of the aerosol forcing. Specifically, the aerosol cooling effect exceeds the GHG warming effect in the Kuroshio Extension(KE) region dur- ing 1950–2004 in the CM3 single forcing. The mid-latitude response of ocean circulation to the GHG(aerosol) forcing is to enhance(weaken) the Subtropical Gyre. Then the SST warming(cooling) lies on the zonal band of 40?N because of the increased(reduced) KE warm advection effect in the GHG(aerosol) forcing simulations, and the cooling effect to SST will surpass the warming effect in the KE region in the historical all-forcing simulations. Besides, the positive feedback between cold SST and cloud can also strengthen the aerosol cooling effect in the KE region during boreal summer, when the mixed layer depth is shallow. In the GHG(aerosol) forcing simulations, corresponding to warming(cooling) SST in the KE region, the weakened(enhanced) Aleutian Low appears in the Northeast Pacific. Consequently, the SST responses to all-forcing in the historical simulations are similar to the re- sponses to aerosol forcing in sign and spatial pattern, hence the aerosol effect is quite important to the SST cooling in the mid-latitude North Pacific during the past 55 years.  相似文献   

6.
The tendency of South China Sea throughflow (SCSTF) variation associated with the local monsoon system, and its impact on upper-layer thermal structure, are studied using the Simple Ocean Data Assimilation (SODA) dataset, combined with Ishii reanalysis data. Luzon Strait Transport (LST) is measured and used as an index for studying the SCSTF variation. Results show that LST had an increasing tendency over the last 50 years, mainly in summer and fall. The increasing tendency was 0.017 1 Sv/a in summer and 0.027 4 Sv/a in fall, as estimated by SODA, and 0.018 0Sv/a in summer and 0.018 9 Sv/a in fall, as estimated by "Island Rule" theory. LST increased by 0.53Sv in JJA (June-July-August) and 0.98Sv in SON (September-October-November) after climate shift, as inferred by SODA data. The average LST anomaly in JJA and SON is strongly related to the local monsoon system, especially to variability of the meridional wind stress anomaly after application of a 3-year running mean, with correlation coefficients 0.57 and 0.51, respectively. In addition to the basin-scale wind forcing, the local northeasterly wind stress anomaly in the SCS can push Pacific water entering the SCS more readily in JJA and SON after climate shift, and an SCSTF-associated cooling effect may favor subsurface cooling more frequently after climate shift.  相似文献   

7.
This study examines the modulation of tropical cyclogenesis over the South China Sea(SCS) by the El Nio-Southern Oscillation(ENSO) Modoki during the boreal summer. Results reveal that there were more tropical cyclones(TCs) formed over the SCS during central Pacific warming years and less TC frequency during central Pacific cooling years. How different environmental factors(including low-level relative vorticity, mid-level relative humidity, vertical wind shear, and potential intensity) contribute to this influence is investigated, using a genesis potential(GP) index developed by Emanuel and Nolan. Composite anomalies of the GP index are produced for central Pacific warming and cooling years separately, which could account for the changes of TC frequency over the SCS in different ENSO Modoki phases. The degree of contribution by each factor is determined quantitatively by producing composites of modified indices in which only one of the contributing factors varies, with the others set to climatology. The results suggest that the vertical wind shear and low-level relative vorticity, which are associated with the ENSO Modoki-induced anomalous circulations in Matsuno-Gill patterns, make the largest contributions to the ENSO Modoki modulation of tropical cyclogenesis over the SCS as implied by the GP index. These results highlight the important roles of dynamic factors in the modulation of TC frequency over the SCS by the ENSO Modoki during the boreal summer.  相似文献   

8.
El Nio events with an eastern Pacific pattern(EP) and central Pacific pattern(CP) were first separated using rotated empirical orthogonal functions(REOF).Lead/lag regression and rotated singular value decomposition(RSVD) analyses were then carried out to study the relation between the surface zonal wind(SZW) anomalies and sea surface temperature(SST) anomalies in the tropical Pacific.A possible physical process for the CP El Ni o was proposed.For the EP El Ni o,strong westerly anomalies that spread eastward continuously produce an anomalous ocean zonal convergence zone(ZCZ) centered on about 165°W.This SZW anomaly pattern favors poleward and eastward Sverdrup transport at the equator.For the CP El Nio,westerly anomalies and the ZCZ are mainly confined to the western Pacific,and easterly anomalies blow in the eastern Pacific.This SZW anomaly pattern restrains poleward and eastward Sverdrup transport at the equator;however,there is an eastward Sverdrup transport at about 5°N,which favors the warming of the north-eastern tropical Pacific.It is found that the slowness of eastward propagation of subsurface warm water(partly from the downwelling caused by Ekman convergence and the ZCZ) is due to the slowdown of the undercurrent in the central basin,and vertical advection in the central Pacific may be important in the formation and disappearance of the CP El Nio.  相似文献   

9.
The Sea Level Anomaly-Torque (SLAT, relative to a reference location in the Pacific Ocean), which means the total torque of the gravity forces of sea waters with depths equal to the Sea Level Anomaly (SLA) in the tropical Pacific Ocean, is defined in this study. The time series of the SLAT from merged altimeter data (1993-2003) had a great meridional variation during the 1997-1998 El Nio event. By using historical upper layer temperature data (1955-2003) for the tropical Pacific Ocean, the tempera- ture-based SLAT is also calculated and the meridional variation can be found in the historical El Nio events (1955-2003), which suggests that the meridional shifts of the sea level anomaly are also intrinsic oscillating modes of the El Nio cycles like the zonal shifts.  相似文献   

10.
Analysis on long-term change of sea surface temperature in the China Seas   总被引：4，自引：0，他引：4  
Long-term change of sea surface temperature (SST) in the China Seas from 1900 to 2006 is examined based on two different observation datasets (HadISST1 and HadSST3). Similar to the Atlantic, SST in the China Seas has been well observed dur-ing the past 107 years. A comparison between the reconstructed (HadISST1) and un-interpolated (HadSST3) datasets shows that the SST warming trends from both datasets are consistent with each other in most of the China Seas. The warming trends are stronger in winter than in summer, with a maximum rate of SST increase exceeding 2.7℃ (100 year)-1 in the East China Sea and the Taiwan Strait during winter based on HadISST1. However, the SST from both datasets experienced a sudden decrease after 1999 in the China Seas. The estimated trend from HadISST1 is stronger than that from HadSST3 in the East China Sea and the east of Taiwan Island, where the difference in the linear SST warming trends are as large as about 1℃ (100 year)-1 when using respectively HadISST1 and HadSST3 datasets. When compared to the linear winter warming trend of the land surface air temperature (1.6℃ (100 year)-1), HadSST3 shows a more reasonable trend of less than 2.1℃ (100 year)-1 than HadISST1’s trend of larger than 2.7℃ (100 year)-1 at the mouth of the Yangtze River. The results also indicate large uncertainties in the estimate of SST warming patterns.  相似文献   

11.
Liu  Zenghong  Chen  Xingrong  Sun  Chaohui  Wu  Xiaofen  Lu  Shaolei 《中国海洋湖沼学报》2017,35(3):712-721
Satellite SST(sea surface temperature) from the Advanced Microwave Scanning Radiometer for the Earth Observing System(AMSR-E) is compared with in situ temperature observations from Argo profiling floats over the global oceans to evaluate the advantages of Argo NST(near-surface temperature: water temperature less than 1 m from the surface). By comparing Argo nominal surface temperature(~5 m) with its NST, a diurnal cycle caused by daytime warming and nighttime cooling was found, along with a maximum warming of 0.08±0.36°C during 14:00–15:00 local time. Further comparisons between Argo 5-m temperature/Argo NST and AMSR-E SST retrievals related to wind speed, columnar water vapor, and columnar cloud water indicate warming biases at low wind speed(5 m/s) and columnar water vapor 28 mm during daytime. The warming tendency is more remarkable for AMSR-E SST/Argo 5-m temperature compared with AMSR-E SST/Argo NST, owing to the effect of diurnal warming. This effect of diurnal warming events should be excluded before validation for microwave SST retrievals. Both AMSR-E nighttime SST/Argo 5-m temperature and nighttime SST/Argo NST show generally good agreement, independent of wind speed and columnar water vapor. From our analysis, Argo NST data demonstrated their advantages for validation of satellite-retrieved SST.  相似文献   

12.
Wind measurements derived from QuikSCAT data were compared with those measured by anemometer on Yongxing Island in the South China Sea (SCS) for the period from April 2008 to November 2009. The comparison confirms that QuikSCAT estimates of wind speed and direction are generally accurate, except for the extremes of high wind speeds (>13.8m/s) and very low wind speeds (<1.5m/s) where direction is poorly predicted. In-situ observations show that the summer monsoon in the northern SCS starts between May 6 and June 1. From March 13, 2010 to August 31, 2010, comparisons of sea surface temperature (SST) and rainfall from AMSR-E with data from a buoy located at Xisha Islands, as well as wind measurements derived from ASCAT and observations from an automatic weather station show that QuikSCAT, ASCAT and AMSR-E data are good enough for research. It is feasible to optimize the usage of remote-sensing data if validated with in-situ measurements. Remarkable changes were observed in wind, barometric pressure, humidity, outgoing longwave radiation (OLR), air temperature, rainfall and SST during the monsoon onset. The eastward shift of western Pacific subtropical high and the southward movement of continental cold front preceded the monsoon onset in SCS. The starting dates of SCS summer monsoon indicated that the southwest monsoon starts in the Indochinese Peninsula and forms an eastward zonal belt, and then the belt bifurcates in the SCS, with one part moving northeastward into the tropical western North Pacific, and another southward into western Kalimantan. This largely determined the pattern of the SCS summer monsoon. Wavelet analysis of zonal wind and OLR at Xisha showed that intra-seasonal variability played an important role in the summer. This work improves the accuracy of the amplitude of intra-seasonal and synoptic variation obtained from remote-sensed data.  相似文献   

13.
It is well known that Tropical cyclone(TC) activities over the Pacific are affected by El Nino events. In most studies El Nino phenomena have been separated into east Pacific warming(EPW) and central Pacific warming(CPW) based on the location of maximum SST anomaly. Since these two kinds of El Nino have different impacts on Pacific tropical cyclone activities, this study investigates different features of TC activities and the genesis potential index(GPI) during EPW years and CPW years. Four contrib- uting factors, i.e., the low-level absolute vorticity, the relative humidity, the potential intensity and the vertical wind shear, are exam- ined to determine which factors are most important in causing the anomalous TC activities. Our results show that during EPW years in July–August(JA0), TC activities are more frequent with stronger intensity over the Western North Pacific(WNP) and Eastern North Pacific(ENP). The maximum anomaly center of TC activities then drifts eastward significantly in September–October(SO0). However, centers of anomalous TC activity barely change from JA0 to SO0 during CPW years. In January–February–March(JFM1) of the decaying years of warming events, TC frequency and intensity both have positive anomaly over the South Pacific. The anoma- lies in EPW years have larger amplitude and wider spatial distribution than those in CPW years. These anomalous activities of TC are associated with GPI anomaly and the key factors affecting GPI anomaly for each ocean basin are quite different.  相似文献   

14.
By using a new heat budget equation that is closely related to the sea surface temperature （SST） and a dataset from an ocean general circulation model （MOM2） with 10-a integration （1987-1996）, the relative importance of various processes determining SST variations in two regions of the Indian Ocean is compared. These regions are defined by the Indian Ocean Dipole Index and will be referred to hereafter as the eastern （0^＊-10^＊S, 90^＊-110^＊E） and western regions （10^＊S- 10^＊N, 50^＊-70^＊E）, respectively. It is shown that in each region there is a falling of SST in boreal summer and a rising in most months of other seasons, but the phases are quite different. In the eastern region, maximum cooling rate occurs in July, whereas in the western region it occurs in June with much larger magnitude. Maximum heating rate occurs in November in the eastern region, but in March in the western one. The western region exhibits another peak of increasing rate of SST in October, indicating a typical half-year period. Net surface heat flux and entrainment show roughly the same phases as the time-varying term, but the former has much larger contribution in most of a year, whereas the latter is important in the boreal summer. Horizontal advection, however, shows completely different seasonal variations as compared with any other terms in the heat budget equation. In the eastern region, it has a maximum in June/November and a minimum in March/ September, manifesting a half-year period; in the western region, it reaches the maximum in August and the minimum in November. Further investigation of the horizontal advection indicates that the zonal advection has almost the opposite sign to the meridional advection. In the eastern region, the zonal advection is negative with a peak in August, whereas the meridional one is positive with two peaks in June and October. In the western region, the zonal advection is negative from March to November with two peaks in June and November, whereas the meridional one is positive with one peak in July. Different phases can be clearly seen between the two regions for each component of the horizontal advection. A detailed analysis of the data of 1994, a year identified when the Indian Ocean dipole event happened, indicates that the horizontal advection plays a dominant role in the remarkable cooling of the eastern region, in which zonal and meridional advections have the same sign of anomaly. However, in the western region in 1994 no any specialty was shown as compared with other years, for the SST anomaly is not positive in large part of this region. All these imply that the eastern and western regions may be related in a quite complex way and have many differences in dynamics. Further study is needed.  相似文献   

15.
Perturbed solving method for interdecadal sea-air oscillator model   总被引：1，自引：0，他引：1  
A coupled system of the interdecadal sea-air oscillator model is studied.The El Nio-southern oscillation(ENSO) atmospheric physics oscillation is an abnormal phenomenon involved in the tropical Pacific ocean-atmosphere interactions.The oscillator model is involved with the variations of both the eastern and western Pacific anomaly pat-terns.This paper proposes an ENSO atmospheric physics model using a method of the perturbation theory.The aim is to create an asymptotic solving method for the ENSO model.Employing the perturbed method,the asymptotic solution of corresponding problem is obtained,and the asymptotic behaviour of the solution is studied.Thus we can obtain the prognoses of the sea surface temperature anomaly and related physical quantities.  相似文献   

16.
To reconstruct the productivity changes for the last 10 500 a in the northeastern East China Sea (ECS),biogenic compounds (such as carbonate,organic carbon and opal),marine micropaleontological fossils (planktonic foraminifera,benthic foraminifera,radiolarian and silicoflagellate) and the compositional characters of benthic foraminifera fauna analyses were carried out on a sediment core DOC082 obtained from the western slope of Okinawa Trough (29°13.93'N,128°08.53'E;1 128 m water depth).The long-term changes of biogenic and micropaleontological proxies display some similarities through the last 10 500 a,which show three different phases:lower values are recorded during the early and middle Holocene (before about 4 000 a BP),followed by an abrupt and remarkable increase at about 4 000 a BP,the late Holocene (after about 3 000 a BP) is characterized by continuously high values.The multi-proxy data of paleoproductivity and percents of benthic foraminifera genera (Uvigerina and Bulimina) show that during the early and middle Holocene (10 500-4 000 a BP) productivity was relatively low with a sudden and distinct increase at about 4 000 a BP,and the late Holocene (3 400-0 a BP) is marked by significantly higher productivity.Also,the radiolarian-based sea surface temperature (SST) records reveal a distinct decline in SST in the late Holocene after 3 200 a BP,very different from the early and middle Holocene.For the last 3 000 a,the enhanced biological productivity and distinctly lower SST indicate a major change of oceanographic conditions in the northeastern ECS.These marine environmental anomalies are consistent with other paleoclimatic records for the late Holocene in the Chinese continent and its surrounding regions.After analyzing the mechanisms of modern productivity and SST changes in the northeastern ECS,and based on the climatic anomalies in the Chinese continent and variations in the Kuroshio Current during modern El Nio periods,we suggest that the anomalous environmental conditions in the northeastern ECS may imply intensified El Nio activity during the late Holocene.  相似文献   

17.
Yang  Bing  Hou  Yijun  Li  Min 《中国海洋湖沼学报》2019,37(3):938-956
Based on in-situ observation, satellite and reanalysis data, responses of the western North Pacific subtropical ocean(WNPSO) to the slow-moving category 5 super typhoon Nanmadol in 2011 are analyzed. The dynamical response is dominated by near-inertial currents and Ekman currents with maximum amplitude of 0.39 m/s and 0.15 m/s, respectively. The near-inertial currents concentrated around 100 m below the sea surface and had an e-folding timescale of 4 days. The near-inertial energy propagated both upward and downward, and the vertical phase speed and wavelength were estimated to be 5 m/h and 175 m, respectively. The frequency of the near-inertial currents was blue-shifted near the surface and redshifted in ocean interior which may relate to wave propagation and/or background vorticity. The resultant surface cooling reaches -4.35℃ and happens when translation speed of Nanmadol is smaller than 3.0 m/s.When Nanmadol reaches super typhoon intensity, the cooling is less than 3.0℃ suggesting that the typhoon translation speed plays important roles as well as typhoon intensity in surface cooling. Upwelling induced by the slow-moving typhoon wind leads to typhoon track confined cooling area and the right-hand bias of cooling is slight. The mixed layer cooling and thermocline warming are induced by wind-generated upwelling and vertical entrainment. Vertical entrainment also led to mixed layer salinity increase and thermocline salinity decrease, however, mixed layer salinity decrease occurs at certain stations as well. Our results suggest that typhoon translation speed is a vital factor responsible for the oceanic thermohaline and dynamical responses, and the small Mach number(slow typhoon translation speed) facilitate development of Ekman current and upwelling.  相似文献   

18.
Effects of extratropical solar penetration on the North Atlantic Ocean circulation and climate are investigated using a coupled ocean-atmosphere model.In this model,solar penetration generates basinwide cooling and warming in summer and winter,respectively.Associated with SST changes,annual mean surface wind stress is intensified in both the subtropical and subpolar North Atlantic,which leads to acceleration of both subtropical and subpolar gyres.Owing to warming in the subtropics and significant saltiness in the subpolar region,potential density decreases(increases) in the subtropical(subpolar)North Atlantic.The north-south meridional density gradient is thereby enlarged,accelerating the Atlantic meridional overturning circulation(AMOC).In addition,solar penetration reduces stratification in the upper ocean and favors stronger vertical convection,which also contributes to acceleration of the AMOC.  相似文献   

19.
Process of sea surface diurnal warming has drawn a lot of attention in recent years, but that occurs in shelf seas was rarely addressed. In the present work, surface diurnal warming strength in the East China Sea was calculated by the sea surface temperature(SST) data derived from the MODIS sensors carried by the satellites Aqua and Terra. Due to transit time difference, both the number of valid data and the surface diurnal warming strength computed by the MODIS-Aqua data are relatively larger than Terra. Therefore, the 10-year MODIS-Aqua data from 2005 to 2014 were used to analyze the monthly variability of the surface diurnal warming. Generally, the surface diurnal warming in the East China sea is stronger in summer and autumn but weaker in winter and spring, while it shows different peaks in different regions. Large events with ΔT≥5 K have also been discussed. They were found mainly in coastal area, especially near the Changjiang(Yangtze) River estuary. And there exists a high-incidence period from April to July. Furthermore, the relationship between surface diurnal warming and wind speed was discussed. Larger diurnal warming mainly lies in areas with low wind speed. And its possibility decreases with the increase of wind speed. Events with ΔT ≥2.5 K rarely occur when wind speed is over 12 m/s. Study on surface diurnal warming in the East China Sea may help to understand the daily scale air-sea interaction in the shelf seas. A potential application might be in the marine weather forecasts by numerical models. Its impact on the coastal eco-system and the activities of marine organisms can also be pursued.  相似文献   

20.
Empirical orthogonal function (EOF) analysis reveals a co-variability of Sea surface temperatures (SSTs) in the Southern Hemisphere (0°-60°S). In the South Indian and Atlantic Oceans, there is a subtropical dipole pattern slanted in the southwest- north-east direction. In the South Pacific Ocean, a meridional tripole structure emerges, whose middle pole co-varies with the dipoles in the South Indian and Atlantic Oceans and is used in this study to track subtropical Pacific variability. The South Indian and Atlantic Ocean dipoles and the subtropical Pacific variability are phase-locked in austral summer. On the inter-decadal time scales, the dipoles in the South Indian and Atlantic Oceans weaken in amplitude after 1979/1980. No such weakening is found in the subtropical South Pacific Ocean. Interestingly, despite the reduced amplitude, the correlation of the Indian Ocean and Atlantic dipoles with El Nio and Southern Oscillation (ENSO) are enhanced after 1979/1980. The same increase in correlation is found for subtropical South Pacific variability after 1979/1980. These inter-decadal modulations imply that the Southern Hemisphere participates in part of the climate shift in the late 1970s. The correlation between Southern Hemisphere SST and ENSO reduces after 2000.  相似文献   

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