Abrupt climate changes of Holocene

This paper is a review of studies of abrupt climate changes(ACCs) during the Holocene published during the past ten years.North Atlantic cold events are indicators of ACCs.As indicated by North Atlantic ice-rafted debris(IRD),there were nine confirmed cold events during the Holocene,occurring at 11.1 kyr,10.3 kyr,9.4 kyr,8.1 kyr,5.9 kyr,4.2 kyr,2.8 kyr,1.4 kyr,and 0.4 kyr respectively according to most representative results from Bond et al.(1997).However,the identification of chronology has been made with some uncertainties.Considerable climatic proxy data have shown that,during the cold events,substantial climate abnormalities have occurred widely across the globe,particularly in the areas surrounding the North Atlantic.These abnormalities were in the form of high-latitude cold in the both hemispheres,expansion of the Westerlies to low latitudes,drought in the monsoon regions,recession of summer monsoons,and intensification of the winter monsoons.Studies have indicated that the four ACCs occurring in the early Holocene may be related to freshwater pulses from ice melting in the northern part of the North Atlantic,and the other five ACCs that occurred during the middle and late Holocene may be related to the decreased solar activity.     

Holocene climate cycles in northwest margin of Asian monsoon

In the mid-latitude regions of the Asian continent,Zhuye Lake is located in the northwest margin of the Asian monsoon,where the modern climate is affected by the Asian monsoon and Westerlies.In this study,we investigated the absolutely dated Holocene records in Zhuye Lake for detecting the Holocene climate cycles.Totally,14 14 C dates and 6 optically simulated luminescence(OSL) dates are obtained from the QTH01 and QTH02 sections.The proxies of grain-size,total organic carbon content(TOC),C/N and δ 13 C are used for wavelet analysis,and the results show obvious ~256,~512 and ~1024-year climate cycles,which are consistent with the Holocene millennial and centennial scale climate cycles in the typical Asian summer monsoon domain.In different parts of the Zhuye Lake,the Holocene sediments show variable climate cycles that are affected by the lake basin topography.In the Zhuye Lake,the Holocene climate cycles are mainly correlated with the solar-related Asian summer monsoon variability and the North Atlantic ice-rafting events.     

Modeling Arctic Ocean heat transport and warming episodes in the 20th century caused by the intruding Atlantic Water

This study investigates the Arctic Ocean warming episodes in the 20th century using both a high-resolution coupled global climate model and historical observations. The model, with no flux adjustment, reproduces well the Atlantic Water core temperature （AWCT） in the Arctic Ocean and shows that four largest decadalscale warming episodes occurred in the 1930s, 70s, 80s, and 90s, in agreement with the hydrographic observational data. The difference is that there was no pre-warming prior to the 1930s episode, while there were two pre-warming episodes in the 1970s and 80s prior to the 1990s, leading the 1990s into the largest and prolonged warming in the 20th century. Over the last century, the simulated heat transport via Fram Strait and the Barents Sea was estimated to be, on average, 31.32 TW and 14.82 TW, respectively, while the Bering Strait also provides 15.94 TW heat into the west- ern Arctic Ocean. Heat transport into the Arctic Ocean by the Atlantic Water via Fram Strait and the Barents Sea correlates significantly with AWCT （ C = 0.75 ） at 0- lag. The modeled North Atlantic Oscillation （NAO） index has a significant correlation with the heat transport （ C = 0.37 ）. The observed AWCT has a significant correlation with both the modeled AWCT （ C =0.49） and the heat transport （ C =0.41 ）. However, the modeled NAO index does not significantly correlate with either the observed AWCT （ C = 0.03 ） or modeled AWCT （ C = 0.16 ） at a zero-lag, indicating that the Arctic climate system is far more complex than expected.     

Influences of two types of El Ni?o event on the Northwest Pacific and tropical Indian Ocean SST anomalies

Based on the Had ISST1 and NCEP datasets,we investigated the influences of the central Pacific El Ni?o event(CP-EL)and eastern Pacific El Ni?o event(EP-EL)on the Sea Surface Temperature(SST)anomalies of the Tropical Indian Ocean.Considering the remote ef fect of Indian Ocean warming,we also discussed the anticyclone anomalies over the Northwest Pacific,which is very important for the South China precipitation and East Asian climate.Results show that during the El Ni?o developing year of EP-EL,cold SST anomalies appear and intensify in the east of tropical Indian Ocean.At the end of that autumn,all the cold SST anomaly events lead to the Indian Ocean Dipole(IOD)events.Basin uniform warm SST anomalies exist in the Indian Ocean in the whole summer of EL decaying year for both CP-and EP-ELs.However,considering the statistical significance,more significant warm SST anomalies only appear in the North Indian Ocean among the June and August of EP-EL decaying year.For further research,EP-EL accompany with Indian Ocean Basin Warming(EPI-EL)and CP El Ni?o accompany with Indian Ocean Basin Warming(CPI-EL)events are classified.With the remote ef fects of Indian Ocean SST anomalies,the EPI-and CPI-ELs contribute quite differently to the Northwest Pacific.For the EPI-EL developing year,large-scale warm SST anomalies arise in the North Indian Ocean in May,and persist to the autumn of the El Ni?o decaying year.However,for the CPI-EL,weak warm SST anomalies in the North Indian Ocean maintain to the El Ni?o decaying spring.Because of these different SST anomalies in the North Indian Ocean,distinct zonal SST gradient,atmospheric anticyclone and precipitation anomalies emerge over the Northwest Pacific in the El Ni?o decaying years.Specifically,the large-scale North Indian Ocean warm SST anomalies during the EPI-EL decaying years,can persist to summer and force anomalous updrafts and rainfall over the North Indian Ocean.The atmospheric heating caused by this precipitation anomaly emulates atmospheric Kelvin waves accompanied by low level easterly anomalies over the Northwest Pacific.As a result,a zonal SST gradient with a warm anomaly in the west and a cold anomaly in the east of Northwest Pacific is generated locally.Furthermore,the atmospheric anticyclone and precipitation anomalies over the Northwest Pacific are strengthened again in the decaying summer of EPI-EL.Af fected by the local WindEvaporation-SST(WES)positive feedback,the suppressed East Asian summer rainfall then persists to the late autumn during EPI-EL decaying year,which is much longer than that of CPI-EL.     

Impacts of climatic change on river runoff in northern Xinjiang of China over last fifty years

The characteristics of climatic change and river runoff, as well as the response of river runoff to climatic change in the northern Xinjiang are analyzed on the basis of the hydrological and meteorological data over the last 50 years by the methods of Mann-Kendall nonparametric test and the nonlinear regression model. The results show that: 1) The temperature and the precipitation increased significantly in the whole northern Xinjiang, but the precipitation displayed no obvious change, or even a decreasing trend in the northern mountainous area of the northern Xinjiang. 2) River runoff varied in different regions in the northern Xinjiang. It significantly increased in the northern slope of the Tianshan Mountains and the north of the northern Xinjiang (p=0.05), while slightly increased in the west of the northern Xinjiang. 3) North Atlantic Oscillation (NAO) affects river runoff by influencing temperature and precipita-tion. The NAO and precipitation had apparent significant correlations with the river runoff, but the temperature did not in the northern Xinjiang. Since the mid-1990s river runoff increase was mainly caused by the increasing temperature in the northern slope of the Tianshan Mountains and the north of the northern Xinjiang. Increased precipitation resulted in increased river runoff in the west of the northern Xinjiang.     

Extreme Flood Events over the Past 300 Years Inferred from Lake Sedimentary Grain Sizes in the Altay Mountains,Northwestern China

Understanding the temporal variations of extreme floods that occur in response to climate change is essential to anticipate the trends in flood magnitude and frequency in the context of global warming. However, long-term records of paleofloods in arid regions are scarce, thus preventing a thorough understanding of such events. In this study, a reconstruction of paleofloods over the past 300 years was conducted through an analysis of grain sizes from the sediments of Kanas Lake in the Altay Mountains of northwestern China. Results showed that grain parameters and frequency distributions can be used to infer possible abrupt environmental events within the lake sedimentary sequence, and two extreme flood events corresponding to ca. 1736–1765 AD and ca. 1890 AD were further identified based on canonical discriminant analysis(CDA) and coarse percentile versus median grain size(C-M) pattern analysis, both of which occurred during warmer and wetter climate conditions by referring to tree-ring records. These two flood events are also evidenced by lake sedimentary records in the Altay and Tianshan mountains. Furthermore, through a comparison with other records, the flood event from ca. 1736–1765 AD in the study region seems to have occurred in both the arid central Asia and the Alps in Europe, and thus may have been associated with changes in the North Atlantic Oscillation(NAO) index.     

Grain-size characteristics of sediments formed since 8600 yr B.P. in middle reaches of Yarlung Zangbo River in Tibet and their paleoenvironmental significance

Widespread aeolian sediments have been found in the middle reaches of the Yarlung Zangbo River, China. The grain-size characteristics of sediments from Cha'er Section in the area were analyzed. The results show that the section include one stratum of paleo-mobile dunes, four strata of paleo-semi-fixed dunes, two strata of paleo-fixed dunes, one stratum of sandy immature soils. The paleo-mobile and paleo-somi-fixed dune sand in this section are similar to modern aeolian sand in either grain-size composition or Mz and σ distribution. Compared the above types of dunes each other, the content of sand substance decreases, while the content of silt and clay increases for palco-fixed dunes and sandy immature soils. Combined with age data for each stratum, the analysis shows that these strata are the products of climate changes and the evolution of aeolian landforms. The evolutionary sequence of the paleoclimate and of acolian activities in the valley since 8600 yr B.P. reveals four stages: 8600-5700 yr B.P., when the paleoclimate was cold and dry, with strong winds, thereby activating dunes; 5700-3600 yr B.P., when it was warm and wet, with weak winds, causing dunes to undergo soil-forming processes; 3600-1900 yr B.P., when climate shifted from cold-dry with strong winds to warm-wet with weak winds, and activated dunes were fixed again; and 1900 yr B.P. -present, when the climate became fine, with weak winds, fixing dunes again.     

Millennial-centennial scales climate changes of Holocene indicated by magnetic susceptibility of high-resolution section in Salawusu River valley,China

The upmost segment(Holocene series)of the Milanggouwan stratigraphic section(MGS1)in the Salawusu River valley shows 11 sedimentary cycles of dune sands and fluvio-lacustrine facies,or dune sands and paleosols.The analysis of the magnetic susceptibility of this segment suggests that there are 11 magnetic susceptibility cycles with the value alternating from low to high,in which the layers of the dune sands correspond to the lower value of the magnetic susceptibility and the layers of fluvio-lacustrine facies and paleosols correspond to the higher peaks.The study reveals that the low and high magnetic susceptibility values indicate the climate dominated by cold-arid winter monsoon and warm-humid summer monsoon of East Asia,respectively,and the study area has experienced at least 22 times of mil-lennial-centennial scales climate alternation from the cold-arid to the warm-humid during the Holocene.In terms of the time and the climate nature,the variations basically correspond to those of the North Atlantic and some records of cold-warm changes in China as well.They might be caused by the alternation of winter and summer monsoons in the Mu Us Desert induced by global climate fluctuations in the Holocene.     

Sedimentary Characteristics of the Second Marine Layer During the Late Marine Isotope Stage 3 in Southern Yellow Sea and Their Response to the East Asian Monsoon

We use the particle size of sediments in core YS01 A to study the sedimentary environment of the mud deposit in the central South Yellow Sea of China during late Marine Isotope Stages 3(MIS3;40.5 kyr–31.3 kyr).In addition,the East Asian Monsoon and its relationship with the North Atlantic Ocean climate change are discussed based on the sensitive grain-size calculation and the spectrum analysis.The results show that during late MIS3,the muddy area in the central South Yellow Sea experienced the evolution of coastal facies,shallow marine facies,coastal facies,and continental facies,with weak hydrodynamic conditions.Compared with other climate indicators,we found that there were many century to millennium-scale climate signals documented in the muddy area sediments in the central South Yellow Sea.According to our particle size results,three strong winter monsoon events occurred at 37.6 kyr,35.6 kyr and 32.2 kyr.The East Asian Winter Monsoon records in core YS01 A are consistent with the Greenland ice core and the Hulu cave stalagmite δ~(18)O.The millennial and centennial scale cycles,which are 55 yr,72 yr,115 yr,262 yr respectively,correspond to solar activity cycles,while the 1049 yr and 2941 yr cycles correspond to the Dansgaard-Oeschger cycles.These cycles indicate that the paleoclimate evolution of the area was controlled by the solar activities,with the high-latitude driving thermohaline circulation as the main energy conveyor belt,followed by the sea-air-land amplification of the winter monsoon variation in the central Yellow Sea in the late MIS3.     

Tropical Atlantic climate response to different freshwater input in high latitudes with an ocean-only general circulation model

Tropical Atlantic climate change is relevant to the variation of Atlantic meridional overturning circulation (AMOC) through different physical processes. Previous coupled climate model simulation suggested a dipole-like SST structure cooling over the North Atlantic and warming over the South Tropical Atlantic in response to the slowdown of the AMOC. Using an ocean-only global ocean model here, an attempt was made to separate the total influence of various AMOC change scenarios into an oceanic-induced component and an atmospheric-induced component. In contrast with previous freshwater-hosing experiments with coupled climate models, the ocean-only modeling presented here shows a surface warming in the whole tropical Atlantic region and the oceanic-induced processes may play an important role in the SST change in the equatorial south Atlantic. Our result shows that the warming is partly governed by oceanic process through the mechanism of oceanic gateway change, which operates in the regime where freshwater forcing is strong, exceeding 0.3 Sv. Strong AMOC change is required for the gateway mechanism to work in our model because only when the AMOC is sufficiently weak, the North Brazil Undercurrent can flow equatorward, carrying warm and salty north Atlantic subtropical gyre water into the equatorial zone. This threshold is likely to be model-dependent. An improved understanding of these issues may have help with abrupt climate change prediction later.     

Effects of extratropical solar penetration on North Atlantic Ocean circulation and climate

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.     

Drought Forecasting in a Semi-arid Watershed Using Climate Signals:a Neuro-fuzzy Modeling Approach

Large-scale annual climate indices were used to forecast annual drought conditions in the Maharlu-Bakhtegan watershed,located in Iran,using a neuro-fuzzy model.The Standardized Precipitation Index（SPI） was used as a proxy for drought conditions.Among the 45 climate indices considered,eight identified as most relevant were the Atlantic Multidecadal Oscillation（AMO）,Atlantic Meridional Mode（AMM）,the Bivariate ENSO Time series（BEST）,the East Central Tropical Pacific Surface Temperature（NINO 3.4）,the Central Tropical Pacific Surface Temperature（NINO 4）,the North Tropical Atlantic Index（NTA）,the Southern Oscillation Index（SOI）,and the Tropical Northern Atlantic Index（TNA）.These indices accounted for 81% of the variance in the Principal Components Analysis（PCA） method.The Atlantic surface temperature（SST：Atlantic） had an inverse relationship with SPI,and the AMM index had the highest correlation.Drought forecasts of neuro-fuzzy model demonstrate better prediction at a two-year lag compared to a stepwise regression model.     

Interannual wave climate variability in the Taiwan Strait and its relationship to ENSO events

This study investigated the interannual wave climate variability in the Taiwan Strait(TS) and its relationship to the El Ni?o-Southern Oscillation(ENSO) phenomenon using a high-resolution numerical wave model. The results showed the interannual variability of significant wave height(SWH) in the TS, which exhibits significant spatial and seasonal variations, is typically weaker than the seasonal variability. The standard deviation of the interannual SWH anomaly(SWHA) showed similar spatial variations in the TS throughout the year, being largest in the middle of the strait and decreasing shoreward, except in summer, when there was no local maximum in the middle of the TS. Further analyses proved the interannual wave climate variability in the TS is controlled predominantly by tropical cyclone activities in summer and by the northeasterly monsoon winds in winter. Furthermore, the interannual SWHA in the TS was found correlated highly negatively with the ENSO phenomenon. This relationship mainly derives from that during the northeasterly monsoon seasons. During the northeasterly monsoon seasons in El Ni?o(La Ni?a) years, the negative(positive) SWHA in the TS derives from weakened(strengthened) northeasterly monsoon winds induced by a lower-tropospheric anomalous anticyclone(cyclone) over the western Pacific Ocean and the South China Sea. During the southwesterly monsoon season in El Ni?o(La Ni?a) years, however, the SWH in the TS tends to increase(decrease) anomalously because of intensified(weakened) TC activities over the western North Pacific Ocean and adjacent seas.     

Middle Holocene warm period and sea level high in coastal areas,North China

Relevant geological, geographical, archaeological data were collected to study the characteristics of middle Holocene warm period and sea level high on North China coast. Middle Holocene climate and sea level change on North China coast were correlated to warm marine environment events in about 8-3 ka B.E The sea level in about 8 ka B.E was higher than present mean sea level, then fluctuated for 5 000 years and after that it became even in 3 ka B.E The highest sea level occurred in about 6-5 ka B.E; the maximum was about 2-3 m and minimum was about 1-2 m.     

ENSO cycle and climate anomaly in China

The inter-annual variability of the tropical Pacific Subsurface Ocean Temperature Anomaly (SOTA) and the associated anomalous atmospheric circulation over the Asian North Pacific during the El Ni o-Southern Oscillation (ENSO) were investigated using National Centers for Environmental Prediction/ National Center for Atmospheric Research (NCEP/NCAR) atmospheric reanalysis data and simple ocean data simulation (SODA). The relationship between the ENSO and the climate of China was revealed. The main results indicated the following: 1) there are two ENSO modes acting on the subsurface tropical Pacific. The first mode is related to the mature phase of ENSO, which mainly appears during winter. The second mode is associated with a transition stage of the ENSO developing or decaying, which mainly occurs during summer; 2) during the mature phase of El Ni o, the meridionality of the atmosphere in the mid-high latitude increases, the Aleutian low and high pressure ridge over Lake Baikal strengthens, northerly winds prevail in northern China, and precipitation in northern China decreases significantly. The ridge of the Ural High strengthens during the decaying phase of El Ni o, as atmospheric circulation is sustained during winter, and the northerly wind anomaly appears in northern China during summer. Due to the ascending branch of the Walker circulation over the western Pacific, the western Pacific Subtropical High becomes weaker, and south-southeasterly winds prevail over southern China. As a result, less rainfall occurs over northern China and more rainfall over the Changjiang River basin and the southwestern and eastern region of Inner Mongolia. The flood disaster that occurred south of Changjiang River can be attributed to this. The La Ni a event causes an opposite, but weaker effect; 3) the ENSO cycle can influence climate anomalies within China via zonal and meridional heat transport. This is known as the "atmospheric-bridge", where the energy anomaly within the tropical Pacific transfers to the mid-high latitude in the northern Pacific through Hadley cells and Rossby waves, and to the western Pacific-eastern Indian Ocean through Walker circulation. This research also discusses the special air-sea boundary processes during the ENSO events in the tropical Pacific, and indicates that the influence of the subsurface water of the tropical Pacific on the atmospheric circulation may be realized through the sea surface temperature anomalies of the mixed water, which contact the atmosphere and transfer the anomalous heat and moisture to the atmosphere directly. Moreover, the reason for the heavy flood within the Changjiang River during the summer of 1998 is reviewed in this paper.     

“海上丝绸之路”主要海域热带气旋时空分布特征及其危险性

热带气旋作为一种海上灾害性天气,对“海上丝绸之路”海上航运影响重大。本文基于西北太平洋和北印度洋1990—2017年的热带气旋路径数据,结合热带气旋风场参数模型,利用缓冲区分析、叠加分析等GIS空间分析技术,系统研究了“海上丝绸之路”主要海域、主要海区、关键通道受热带气旋影响频次以及热带气旋危险性的时空分布特征。主要结论：① “海上丝绸之路”主要海域受热带气旋影响严重,表现在热带气旋影响范围广、影响频次高,其中西北太平洋较北印度洋受热带气旋影响更为严重,危险性更大;② 西北太平洋的15°N—30°N,120°E-—145°E海域热带气旋危险性最高;③ 热带气旋危险性季节变化较为明显,秋夏两季危险性较高,冬春两季危险性较低,在夏秋两季各月份中,7、8、9、10月危险最高;④ 在各海区中,中国东部海区热带气旋危险最高,其次是南海、日本海、孟加拉湾、阿拉伯海,而红海和波斯湾不受热带气旋影响;在各关键通道中,吕宋海峡热带气旋危险性最高,其次是台湾海峡、对马海峡、宗谷海峡、鞑靼海峡、保克海峡、霍尔木兹海峡,而马六甲海峡和曼德海峡无热带气旋危险。     

The Holocene warm-humid phases in the North China Plain as recorded by multi-proxy records

The grain size and palinology of sediment and the frequency of 14C dada provide an integrated reconstruction of the Holocene warm-humid phases of the North China Plain. Two clear intense and long-lasting warm-humid phases were identified by comprehensive research in this region. The first phase was dated back to the early Holocene (9 000–7 000 a BP), and the second was centered at 5 000–3 000 a BP. The warm-humid episode between 9 000 and 7 000 a BP was also recognized at other sites showing global climatic...     

A singular spectrum analysis on Holocene climatic oscillation from lake sedimentary record in Minqin Basin, China

The total organic carbon (TOC) content series from the lake sediment of Minqin Basin (100°57′–104°57′E, 37°48′–39°17′N) in northwestern China, which has a 10 000-year-long paleo-climatic proxy record, was used to analyze the Holocene climate changes in the local region. The proxy record was established in the Sanjiaocheng (SJC), Triangle Town in Chinese, Section (103°20′25″E, 39°00′38″N), which is located at the northwestern boundary of the present Asian summer monsoon in China, and is sensitive to global environmental and climate changes. Applying singular spectrum analysis (SSA) to the TOC series, principal climatic oscillations and periodical changes were studied. The results reveal 3 major patterns of climate change regulated by reconstructed components (RCs). The first pattern is natural long-term trend of climatic change in the local area (Minqin Basin), indicating a relatively wetter stage in early Holocene (starting at 9.5 kaBP), and a relatively dryer stage with a strong lake desiccation and a declined vegetation cover in mid-Holocene (during 7–6 kaBP). From 4.0 kaBP to the present, there has been a gradually decreasing trend in the third reconstructed component (RC3) showing that the local climate changed again into a dryer stage. The second pattern shows millennial-centennial scale oscillations containing cycles of 1 600 and 800 years that have been present throughout almost the entire Holocene period of the last 10 000 years. The third pattern is a millennial-centennial scale variation with a relatively smaller amplitude and unclear cycles showing a nonlinear interaction within the earth’s climate systems.     

Sporo-pollen Assemblage and Paleoclimate Events in Shelf Area of the Southern Yellow Sea Since 1.5 ka B.P.

Based on the authors‘ 1986 to 1994 sporo-pollen assemblage analysis in the southern Yellow Sea area, data from 3 main cores were studied in combination with ^14C, palaeomagnetic and thermoluminescence data. The evolution of the paleoclimate environments in the southern Yellow Sea since 15ka B.P. was revealed that, in deglaciation of the last glacial period, the climate of late glaciation transformed into that of postglaciation, accompanied by a series of violent climate fluctuations. These evolution events happened in a global climate background and related to the geographic changes in eastern China. We distinguished three short-term cooling events and two warming events. Among them, the sporo-pollen assemblage of subzone A1 showed some cold climate features indicating that a cooling event occurred at about 15 - 14ka. B .P. in early deglaciation. This subzone corresponds to the Oldest Dryas. In subzone A3 , many drought-enduring herbal pollens and some few pollens of cold-resistant Picea, Abies, etc. were found, which indicated that a cooling event, with cold and arid climate, occurred at about 12- 11ka. B.P. in late deglaciation. This subzone corresponds to the Younger Dryas. The sporo-pollen assemblage of zone B showed warm and arid climate features in postglaciation. Although the assemblage of subzone B2 indicated a cold and arid climate environment, the development of flora in subzone B2 climate was less cold than that in A3 . Subzone B2 indicated a cooling event which occurred at about 9ka B.P. in early Holocene. Subzone A2, with some distinct differences from subzone A1 and A3 , indicated a warming event which occurred at 14 - 13ka. B.P. and should correspond to a warming fluctuation. The sporo-pollen assemblage of zone C showed features of warm-moist flora and climate, and indicated a warming event which universally occurred along the coast of eastern China at 8 - 3ka B.P. in middle Holocene, and its duration was longer than that of any climate events mentioned above. This period was climatic optimum and belonged to an altithermal period in postglaciation.     

Analysis of ERS-2 scatterometer winds and wind-wave calculation for eastern China seas

The wind system over the China seas plays an important role in climate variation there. In this paper, ERS-2 scatterometer winds covering the period of 1998 and the area of 25-41°N, 117-130°E were analyzed and compared to NCEP winds and buoy winds in the same period and location, to assess how well the ERS-2 data reflect the real wind regime, at least for this area. The results indicated that ERS-2 scatterometer winds are closer to buoy observations than NCEP winds. In addition, a new wind-wave growth relation was applied to calculate wave parameters.