Correlation of Rainfall Anomalies in Rwanda from September to December (SOND) with Indian Ocean Dipole (IOD) and El Nino Southern Oscillation (ENSO) Events

Understanding the relationship between rainfall anomalies and large-scale systems is critical for driving adaptation and mitigation strategies in socioeconomic sectors. This study therefore aims primarily to investigate the correlation between rainfall anomalies in Rwanda during the months of September to December (SOND) with the occurrences of Indian Ocean Dipole (IOD) and El Nino Southern Oscillation (ENSO) events. The study is useful for early warning and forecasting of negative effects associated with extreme rainfall anomalies across the country, using Climate Hazards Group InfraRed Precipitation with Station (CHIRPS), the National Centers for Environmental Prediction (NCEP) National Center for Atmospheric Research (NCAR) reanalysis sea surface temperature and ERA5 reanalysis datasets, during the period of 1983-2021. Both empirical orthogonal function (EOF), correlation analysis and composite analysis were used to delineate variability, relationship and the related atmospheric circulation between Rwanda seasonal rainfall September to December (SOND) with Indian Ocean Dipole (IOD) and El-Nino Southern Oscillation (ENSO). The results for Empirical Orthogonal Function (EOF) for the reconstructed rainfall data set showed three modes. EOF-1, EOF-2 and EOF-3 with their total variance of 63.6%, 16.5% and 4.8%, Indian ocean dipole (IOD) events resulted to a strong positive correlation of rainfall anomalies and Dipole model index (DMI) (r = 0.42, p value = 0.001, DF = 37) significant at 95% confidence level. The composite analysis for the reanalysis dataset was carried out to show the circulation patterns during four different events correlated with September to December seasonal rainfall in Rwanda using T-test at 95% confidence level. Wind anomaly revealed that there was a convergence of south westerly winds and easterly wind over the study area during positive Indian Ocean Diploe (PIOD) and PIOD with El Nino concurrence event years. The finding of this study will contribute to the enhancement of SOND seasonal rainfall forecasting and the reduction of vulnerability during IOD (ENSO) event years.

Sea Salt Sodium Record in a Shallow Ice Core from East Antarctica as a Potential Proxy of the Antarctic Sea Ice Extent in Southern Indian Ocean

Antarctic sea ice has experienced an increasing trend in recent decades,especially in the Ross Sea and Indian Ocean sectors.Sea ice variability affects greatly the maritime airmass transport from high latitude to Antarctic continent.Here we present a new ice core record of sea salt sodium(ssNa+)concentration at annual-resolution in the Princess Elizabeth Land spanning from 1990 to 2016,showing that this marker could be used as a potential proxy for reconstructing the sea ice extent(SIE)in the Southern Indian Ocean(SIO)given their significant correlation(R=-0.6,P<0.01)over the past 27 years.The correlation and composite analyses results show that the ssNa^+at the 202 km inland from Zhongshan Station and the SIE changes in SIO are closely related to the Indian Ocean Dipole(IOD)and Southern Annular Mode(SAM).The northward wind in central SIO occurs during positive IOD and the strengthened westerlies occurs during positive SAM,both of which favor increased sea ice in SIO and lead to the decreased ssNa^+concentration at the coastal site.

Distribution characteristics of planktonic nano－and microalgae in the Prydz Bay and its adjacent Southern Indian Ocean，during austral summer

Nano- and microalgae samples were collected from 34 stations in the Prydz Bay and its adjacent Southern indian Ocean, Antarctica during a Period from December 1990 to January 1991. 122 taxa belonging to 40 genera 5 phyla were identified. Among them diatom occupy 73%,dinoflagellates 20. 5%, the other species 6. 5 %. The average cell abundance of nano- and microalgae was 2551×104 cells/m3 in surface waters. The concentration of nano- and microalgae occurred in the Prydz Bay and its adjacent continental station Ⅳ 7 and northern water area between West Ice Shelf and Shackleton Ice Shelf (Stations Ⅶ 3, Ⅷ 1, Ⅷ 2, Ⅷ 3, Ⅸ 1, Ⅺ 1); and minimal abundance occurred in northwestern area of the Prydz Bay (some stations of section Ⅲ and Station Ⅳ 1-5). The average cell abundance of planktonic nano- and microalgae from net sample was 811. 62×104 cells/m3, and the concentration area occurred in the adjacent continent waters of the Prydz Bay (Stations Ⅳ 2, Ⅳ 4, Ⅳ 5, Ⅳ 7, Ⅴ 4 and Ⅴ 5) and northern area of the West Ice Shelf(Stations Ⅶ 1 and Ⅶ 3); low abundance occurred in eastern area of the Shackleton Ice Shelf (at each station of sections Ⅹ and Ⅺ ). For the vertical distribution of planktonic nano- and microalgae, the maximum value was usually found at the surface and above 50 m depth, and gradually decreased with the water depth from 100 m to 200 m. The relationship between planktonic nano-and microalgal abundance and Euphausia superba density and nutrient (nitrate,phosphate and silicate) contents were negative significance.

Features and spatial distribution of circumpolar deep water in the southern Indian Ocean and the effects of Antarctic circum polar current

The data from the Southern Ocean observations of World Ocean Circulation Experiment （WOCE） are used for analysis and illustration of the features and spatial distributions of Circumpolar Deep Water （CDW） in the southern Indian Ocean. It is learnt from the comparison among the vertical distributions of temperature/ salinity/oxygen along the 30°E, 90°E and 145°E sections respectively that some different features of CDW and the fronts can be found at those longitudes, and those differences can be attributed to the zonal transoceanic flow and the merizonal movement in the Circumpolar Deep Water. In fact, the zonal transoceanic flow is the main dynamic factor for the water exchange between the Pacific Ocean and the /ndian Ocean or between the Atlantic Ocean and the Indian Ocean, and for the effects on the spatial distributions of the physical properties in CDW.

Comparisons of surface Chl a and primary productivity along three transects of the southern South China Sea, northern Java Sea and eastern Indian Ocean in April 2011

Results are presented about the changes in chlorophyll a density, carbon fixation and nutrient levels in the surfacewaters of three transects of the southern South China Sea （SCS）, northern Java Sea （JS） and eastern Indian Ocean （IO） duringApril 5-16 of 2011. The in situ Chl a concentration and carbon fixation showed decreasing trends from high to low latitudealong the three transects, while the photosynthetic rate of phytoplankton estimated from 14C incorporation displayed no simplevariation with latitude. Chl a concentration and carbon fixation in the IO water was lower than that in the JS water. Highersalinity and lower contents of dissolved inorganic nitrogen （DIN） and silicate （SiO3^2-） characterized the IO water as comparedto the SCS or JS water, and the PO4^3- content was lower in the IO water than in the SCS or JS water in most cases. Our resultsalso indicate the importance of DIN and SiO3^2- concentrations for the geographical changes in phytoplankton biomass andprimary productivity among the three regions.

Mesoscale surface circulation and variability of Southern Indian Ocean derived by combining satellite altimetry and drifter observations

High resoultion Eulerian mean velocity field has been derived by combining the satellite tracked surface drifter data with satellite altimetry and ocean surface winds. The drifter data used in this study includes Argos and surface drifter data from Global Drifter Program. Maps of Sea Level Anomaly （MSLA） weekly files with a resolution of （1/3）° in both Latitude and Longitude for the period 1993-2012 have been used. The Ekman current is computed using ocean surface mean wind fields from scatterometers onboard ERS 1/2, Quikscat and ASCAT. The derived mean velocity field exhibits the broad flow of Antarctic Circumpolar Current with speeds up to 0.6 m/s. Anomalous field is quite significant in the western part between 20~ and 40~E and in the eastern part between 80~E and 100~E with velocity anomaly up to 0.3 m/s. The estimated mean flow pattern well agrees with the dynamic topography derived from in-situ observations. Also, the derived velocity field is consistent with the in-situ ADCP current measurements. Eddy kinetic energy illustrates an increasing trend during 1993-2008 and is in phase coherence with the Southern Annular Mode by three month lag. Periodic modulations are found in the eddy kinetic energy due the low frequency Antarctic Circumpolar Wave propagation.

Impact of Southern Indian ocean dipole via the ITCZ on winter and spring precipitation in China

本文分析了1979-2021年南印度洋冬季海表面温度特征,印度洋热带辐合带(ITCZ)位置变化及其对中国冬春季降水的影响.EOF分析第一模态表明南印度洋冬季海表面温度异常显示西南-东北反相分布,即南印度洋偶极子模态(SIOD).分离厄尔尼诺-南方涛动(ENSO)信号后,纯SIOD事件对同年冬季和次年春季的印度洋ITCZ位置(35°-75°E平均)均有影响,冬季,纯正(负)SIOD事件使印度洋ITCZ往南(北)移动.春季,SIOD则使印度洋ITCZ移动方向与冬季相反,且移动幅度更大.冬,春季长江中下游地区(MLYR)的降水量与印度洋ITCZ位置分别呈正,负相关.同时,在纯正(负)SIOD事件下,冬,春季MLYR的降水分别减少,增加,可见印度洋ITCZ位置变化可能是SIOD影响MLYR冬,春季降水的媒介之一.

Southern and Tropical Indian Ocean SST: A Possible Predictor of Winter Monsoon Rainfall over South India

The complexities in the relationship between winter monsoon rainfall (WMR) over South India and Sea Surface temperature (SST) variability in the southern and tropical Indian Ocean (STIO) are evaluated statistically. The data of the time period of our study (1950-2003) have been divided exactly in two halves to identify predictors. Correlation analysis is done to see the effect of STIO SST variability on winter monsoon rainfall index (WMRI) for South India with a lead-lag of 8 seasons (two years). The significant positive correlation is found between Southern Indian Ocean (SIO) SST and WMRI in July-August-September season having a lag of one season. The SST of the SIO, Bay of Bengal and North Equatorial Indian Ocean are negatively correlated with WMRI at five, six and seven seasons before the onset of winter monsoon. The maximum positive correlation of 0.61 is found from the region south of 500 S having a lag of one season and the negative correlations of 0.60, 0.53 and 0.57 are found with the SST of the regions SIO, Bay of Bengal and North Equatorial Ocean having lags of five, six and seven seasons respectively and these correlation coefficients have confidence level of 99%. Based on the correlation analysis, we defined Antarctic Circumpolar Current Index A and B (ACCIA (A) & ACCIB (B)), Bay of Bengal index (BOBI (C)) and North Equatorial Index (NEI (D)) by averageing SST for the regions having maximum correlation (positive or negative) with WMRI index. These SST indices are used to predict the WMRI using linear and multivariate linear regression models. In addition, we also attempted to detect a dynamic link for the predictability of WMRI using Nino 3.4 index. The predictive skill of these indices is tested by error analysis and Willmott’s index.

Fronts and surface zonal geostrophic current along 115°E in the southern Indian Ocean

Altimeter and in situ data are used to estimate the mean surface zonal geostrophic current in the section along 115°E in the southern Indian Ocean,and the variation of strong currents in relation to the major fronts is studied.The results show that,in average,the flow in the core of Antarctic Circumpolar Current（ACC） along the section is composed of two parts,one corresponds to the jet of Subantarctic Front（SAF） and the other is the flow in the Polar Front Zone（PFZ）,with a westward flow between them.The mean surface zonal geostrophic current corresponding to the SAF is up to 49 cm · s^-1 at 46°S,which is the maximal velocity in the section.The eastward flow in the PFZ has a width of about 4.3 degrees in latitudes.The mean surface zonal geostrophic current corresponding to the Southern Antarctic Circumpolar Current Front（SACCF） is located at 59.7 °S with velocity less than 20 cm · s^-1.The location of zonal geostrophic jet corresponding to the SAF is quite stable during the study period.In contrast,the eastward jets in the PFZ exhibit various patterns,i.e.,the primary Polar Front（PF1） shows its strong meridional shift and the secondary Polar Front（PF2） does not always coincide with jet.The surface zonal geostrophic current corresponding to SAF has the significant periods of annual,semi-annual and four-month.The geostrophic current of the PFZ also shows significant periods of semi-annual and four-month,but is out of phase with the periods of the SAF,which results in no notable semi-annual and fourmonth periods in the surface zonal geostrophic current in the core of the ACC.In terms of annual cycle,the mean surface zonal geostrophic current in the core of the ACC shows its maximal velocity in June.

Low-Frequency Coupled Atmosphere-Ocean Variability in the Southern Indian Ocean

The low-frequency atmosphere ocean coupled vestigated using observation data over 1958-2010 variability of the southern Indian Ocean （SIO） was in- These data were obtained from ECMWF for sea level pressure （SLP） and wind, from NCEP/NCAR for heat fluxes, and from the Hadley Center for SST. To obtain the coupled air-sea variability, we performed SVD analyses on SST and SLP. The primary coupled mode represents 43% of the total square covariance and is featured by weak westerly winds along 45~ 30~S. This weakened subtropical anticyclone forces fluctuations in a well-known subtropical dipole structure in the SST via wind-induced processes. The SST changes in response to atmosphere forcing and is predictable with a lead-time of 1 2 months. Atmosphere ocean coupling of this mode is strongest during the austral summer. Its principle component is characterized by mixed interannual and interdeeadal fluctuations. Titere is a strong relationship between the first mode and Antarctic Oscillation （AAO）. The AAO can influence tile coupled processes in the SIO by modulating the subtropical high. The second mode, accounting for 30% of the total square covariance, represents a 25-year period interdecadal oscillation in tile strength of the subtropical anticyclone that is accompanied by fluctuations of a monopole structure in the SST along the 35~ 25~S band. It is caused by subsidence of the atmosphere. The present study also shows that physical processes of both local thermodynamic and ocean circulation in the SIO have a crucial role in the fornmtion of the atmosphere-ocean eovariability.

Southern high latitude climate anomalies associated with the Indian Ocean dipole mode

Using a 23-year database consisting of sea level pressure, surface air temperature and sea surface temperature, the authors studied southern high latitude climate anomalies associated with IOD (Indian Ocean Dipole). Correlation analysis of the spatial variability regarding monthly sea level pressure, surface air tempera- ture, and sea surface temperature anomalies with IOD index suggests that IOD signal exists in southern high latitudes. The correlation fields exhibit a wavenumber-3 pattern around the circumpolar Southern Ocean. Lead-lag correlation analysis on the strongest correlation areas with IOD index shows that IOD in the tropical Indian Ocean responses to the southern high latitude climate almost instantaneously. It is proposed in the present paper that this connection is realized through atmospheric propagation rather than through oceanic one.

The regime shift in the 1960s and associated atmospheric change over the southern Indian Ocean

The change of sea surface temperature（SST） in the southern Indian Ocean（SIO） during the recent six decades has been analyzed based on oceanic reanalysis and model, as well as atmospheric data. The results show that a thermal regime shift in SIO during the 1960 s, which is not caught enough attentions, has been of equal magnitude to the linear warming since 1970. Empirical Orthogonal Function（EOF） analyses reveal that a thermal shift is combined with atmospheric changes such as the weakening of westerly during the period of 1960–1967. Inner dynamic connections can be defined that when the westerly winds turn weak, the anticyclonic wind circulation between westerly winds and the trade winds decreases, which further reduces the SST to a negative peak in this period. It is noted that the shifts in the 1960 s are also evident for Southern Hemisphere. For example, subtropical high and the entire westerly winds belt at high latitudes both change dramatically in the 1960 s. This large-scaled process maybe link to the change of southern annular mode（SAM）.

Circulation Pattern Controls of Summer Temperature Anomalies in Southern Africa

This study investigates the relationship between circulation patterns and austral summer temperature anomalies in southern Africa. The results show that the formation of continental lows tends to increase the thickness of the lower atmosphere. Further, the distinct variabilities of high and low pressure under the circulation types, influence air mass advection from the adjacent oceans, as well as atmospheric stability over land. Stronger anticyclonic circulation at the western branch of the Mascarene high-pressure system enhances the low-level cold air advection by southeast winds,decreases the thickness, and lowers the temperature over a majority of the land in southern Africa. Conversely, a weaker Mascarene High, coupled with enhanced cyclonic activity in the southwest Indian Ocean increases low-level warm air advection and increases temperature anomalies over vast regions in southern Africa. The ridging of a closed South Atlantic anticyclone at the southern coast of southern Africa results in colder temperatures near the tip of southern Africa due to enhanced low-level cold air advection by southeast winds. However, when the ridge is weak and westerly winds dominate the southern coast of southern Africa, these areas experience temperature increases. The northward track of the Southern Hemisphere mid-latitude cyclone, which can be linked to the negative Southern Annular Mode, reduces the temperature in the southwestern part of southern Africa. Also, during the analysis period, El Ni?o was associated with temperature increases over the central parts of southern Africa;while the positive Indian Ocean dipole was linked to a temperature increase over the northeastern, northwestern, and southwestern parts of southern Africa.

Decadal/Interdecadal Variations of the Ocean Temperature and its Impacts on Climate

Decadal/interdecadal climate variability is an important research focus of the CLIVAR Program and has been paid more attention. Over recent years, a lot of studies in relation to interdecadal climate variations have been also completed by Chinese scientists. This paper presents an overview of some advances in the study of decadal/interdecadal variations of the ocean temperature and its climate impacts, which includes interdccadal climate variability in China, the interdecadal modes of sea surface temperature （SST） anomalies in the North Pacific, and in particular, the impacts of interdecadal SST variations on the Asian monsoon rainfall. As summarized in this paper, some results have been achieved by using climate diagnostic studies of historical climatic datasets. Two fundamental interdecadal SST variability modes （7- 10-years mode and 25 35-years mode） have been identified over the North Pacific associated with different anomalous patterns of atmospheric circulation. The southern Indian Ocean dipole （SIOD） shows a major feature of interdecadal variation, with a positive （negative） phase favoring a weakened （enhanced） Asian summer monsoon in the following summer. It is also found that the China monsoon rainfall exhibits interdecadal variations with more wet （dry） monsoon years in the Yangtze River （South China and North China） before 1976, but vice versa after 1976. The weakened relationship between the Indian summer rainfall and ENSO is a feature of interdecadal variations, suggesting an important role of the interdecadal variation of the SIOD in the climate over the south Asia and southeast Asia. In addition, evidence indicates that the climate shift in the 1960s may be related to the anomalies of the North Atlantic Oscillation （NAO） and North Pacific Oscillation （NPO）. Overall, the present research has improved our understanding of the decadal/interdecadal variations of SST and their impacts on the Asian monsoon rainfall. However, the research also highlights a number of problems for future research, in particular the mechanisms responsible for the monsoon long4erm predictability, which is a great challenge in climate research.

Impact of the Preceding Boreal Winter Southern Annular Mode on the Summertime Somali Jet

One of the major high-latitude circulation systems in the Southern Hemisphere is the Southern Annular Mode(SAM). Its effect on the Somali Jet(SMJ), which connects the Southern and Northern hemispheres, cannot be ignored. The present reported results show that time series of both the Southern Annular Mode Index(SAMI) during the preceding winter and the summertime Somali Jet intensity Index(SMJI) display a significant increasing trend and have similar interdecadal variation. The latter was rather strong around 1960, then became weaker up to the mid-1980 s, before starting to strengthen again. The lead-lag correlations of monthly mean SAMI with the following summertime SMJI showed significant positive correlations in November, December, and January. There are thus connections across two seasons between the SAM and the SMJ. The influence of the winter SAM on the summer SMJ was explored via analyses of SST anomalies in the Southern Indian Ocean. During strong(weak) SAM/SMJ years, the SST east of Madagascar is colder(warmer) while the SST west of Australia is warmer(colder), corresponding to the positive(negative) Southern Indian Ocean Dipole-like(SIODL) event. Subsequently, the SIODL excites an anticyclone located over the Arabian Sea in summer through air-sea coupling from winter to summer, which causes an increase in the summer SMJ intensity. The anticyclone/high branch of the SAM over the Southern Hemisphere subtropics and the cyclone/low over the east coast of Madagascar play an important role in the formation of Southern Indian Ocean "bridge" from winter to summer.

Effect of El Nino Southern Oscillations on the incidence of enteric fever in Ahmedabad,India from 1985 to 2017

Objective:To explore the relationship between climate variables and enteric fever in the city of Ahmedabad and report preliminary findings regarding the influence of El Nino Southern Oscillations and Indian Ocean Dipole over enteric fever incidence.Method:A total of 29808 Widal positive enteric fever cases reported by the Ahmedabad Municipal Corporation and local climate data in 1985-2017 from Ahmedabad Meteorology Department were analysed.El Nino,La Nina,neutral and Indian Ocean Dipole years as reported by the National Oceanic and Atmospheric Administration for the same period were compared for the incidence of enteric fever.Results:Population-normalized average monthly enteric fever case rates were the highest for El Nino years(25.5),lower for La Nina years(20.5)and lowest for neutral years(17.6).A repeated measures ANOVA analysis showed no significant difference in case rates during the three yearly El Nino Southern Oscillations categories.However,visual profile plot of estimated marginal monthly means showed two distinct characteristics:an early rise and peaking of cases in the El Nino and La Nina years,and a much more restrained rise without conspicuous peaks in neutral years.Further analysis based on monthly El Nino Southern Oscillations categories was conducted to detect differences in median monthly case rates.Median case rates in strong and moderate El Nino months and strong La Nina months were significantly dissimilar from that during neutral months(P<0.001).Conclusions:El Nino Southern Oscillations events influence the incidence of enteric fever cases in Ahmedabad,and further investigation from more cities and towns is required.

Impact of the Future Changing Climate on the Southern Africa Biomes, and the Importance of Geology

The Southern African biomes are complex biotic communities, with its distinctive plant and animal species, and are maintained under the suitable climatic conditions of the region. It includes the Fynbos Biome and the Succulent Karoo Biome, which forms the smallest of the world’s six Floristic Kingdoms, and they are of conservation concern. The other six biomes are Albany Thicket, Desert, Grassland, Indian Ocean Coastal belt, Nama-Karoo, Savanna. The biomes are not only threatened by agricultural expansion, overgrazing, and mining;but also by future climate changes and droughts. This study investigates the how to best model the possible vulnerable biome areas, under future climate changes, and how Southern African geology plays a huge role in the restriction of the biome shifts. It provides evidence regarding the importance of the study to understanding the climate change impacts and the geological variables on the Southern African biomes, in terms of possible future biome habitat loss.

Southern Meridional Atmospheric Circulation Associated with IOD

Using the monthly wind and sea surface temperature （SST） data, southern meridional atmospheric circulation cells associated with the Indian Ocean Dipole Mode （IOD） events in the Indian Ocean are for the first time described and examineS. The divergent wind and pressure vertical velocity are employed for the identification of atmospheric circulation cells. During the four different phases of the positive IOD events, the anomalous meridional Hadley circulation over the western Indian Ocean shows that the air rises in the tropics, flows poleward in the upper troposphere, sinks in the subtropics, and returns back to the tropics in the lower troposphere. The anomalous Hadley circulation over the eastern Indian Ocean is opposite to that over the western Indian Ocean. During positive IOD events, the meridional Hadley circulation over the eastern Indian Ocean is weakened while it is strengthened over the western Indian Ocean. Correlation analysis between the IOD index and the indices of the Hadley cells also proves that, the atmospheric circulation patterns are evident in every IOD event over the period of record.

The influence of tropical Indian Ocean warming on the Southern Hemispheric stratospheric polar vortex

During the past decades, concurrent with global warming, most of global oceans, particularly the tropical Indian Ocean, have become warmer. Meanwhile, the Southern Hemispheric stratospheric polar vortex (SPV) exhibits a deepening trend. Although previous modeling studies reveal that radiative cooling effect of ozone depletion plays a dominant role in causing the deepening of SPV, the simulated ozone-depletion-induced SPV deepening is stronger than the observed. This suggests that there must be other factors canceling a fraction of the influence of the ozone depletion. Whether the tropical Indian Ocean warming (IOW) is such a factor is unclear. This issue is addressed by conducting ensemble atmospheric general circulation model (AGCM) experiments. And one idealized IOW with the amplitude as the observed is prescribed to force four AGCMs. The results show that the IOW tends to warm the southern polar stratosphere, and thus weakens SPV in austral spring to summer. Hence, it offsets a fraction of the effect of the ozone depletion. This implies that global warming will favor ozone recovery, since a warmer southern polar stratosphere is un-beneficial for the formation of polar stratospheric clouds (PSCs), which is a key factor to ozone depletion chemical reactions.

Signals of Antarctic Circumpolar Wave over the Southern Indian Ocean as recorded in an Antarctica ice core

Oxygen stable isotopic and ionic records, cov- ering a period of 1745—1996, are recovered in DT001 ice core drilled in Princess Elizabeth Land, East Antarctica. Using empirical orthogonal function (EOF) analysis of the annually resolved glaciochemical time series, we find the first EOF (EOF1) represents sea-salt aerosols and is the proxy of sea level pressure (SLP) over a quasi-stationary low in the Southern Indian Ocean (SIO). δ O represents the sea sur- 18 face temperature (SST) of the same ocean area. In the past two decades, four climatic waves as represented by SLP and SST proxies are found in the DT001 ice core, which in coin- cident with four Antarctic Circum-polar Waves (ACW) as revealed by NCEP/NCAR reanalysis. The phase difference between SST and SLP in the ice core is also coincident with that in ACW. Both ice-core record and reanalysis suggest that there were no signals of ACW during 1958—1980, none during the overall recording period between 1745—1996, as there is no regular phase difference between SST and SLP. The ACW signal after early 1980s is probably attributable to the climate shift occurring over Antarctic Peninsula-Drake Passage region.