DOCSLIB.ORG

Late Pleistocene and Holocene Paleoenvironments of the North Pacific Coast

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Late Pleistocene and Holocene Paleoenvironments of the North Pacific Coast Quaternary Science Reviews, Vol. 14, pp. 449-47 1, 1995. Pergamon Copyright 0 1995 Elsevier Science Ltd. Printed in Great Britain. All rights reserved. 0277-3791l95 $29.00 0277-3791(9S)ooo&X LATE PLEISTOCENE AND HOLOCENE PALEOENVIRONMENTS OF THE NORTH PACIFIC COAST DANIEL H. MANN* and THOMAS D. HAMILTON? *Alaska Quaternary Center; University of Alaska Museum, 907 Yukon Drive, Fairbanks, AK 99775, U.S.A. I-US. Geological Survey, 4200 University Drive, Anchorage, AK 99508, U.S.A. Abstract - Unlike the North Atlantic, the North Pacific Ocean probably remained free of sea ice during the last glacial maximum (LGM), 22,000 to 17,000 BP. Following a eustatic low in sea level of ca. -120 m at 19,000 BP, a marine transgression had flooded the Bering and Chukchi shelves by 10,000 BP. Post-glacial sea-level history varied widely in other parts of the North QSR Pacific coastline according to the magnitude and timing of local tectonism and glacio-isostatic rebound. Glaciers covered much of the continental shelf between the Alaska Peninsula and British Columbia during the LGM. Maximum glacier extent during the LGM was out of phase between southern Alaska and southern British Columbia with northern glaciers reaching their outer limits earlier, between 23,000 and 16,000 BP, compared to 15,00&14,000 BP in the south. Glacier retreat was also time-transgressive, with glaciers retreating from the continental shelf of southern Alaska before 16,000 BP but not until 14,000-13,000 BP in southwestern British Columbia. Major climat- ic transitions occurred in the North Pacific at 24,000-22,000, 15,000-13,000 and 11,OOO-9000 BP. Rapid climate changes occurred within these intervals, including a possible Younger Dryas episode. An interval of climate warmer and drier than today occurred in the early Holocene. Cooler and wetter conditions accompanied widespread Neoglaciation, beginning in some mountain ranges as early as the middle Holocene, but reaching full development after 3000 BP. INTRODUCTION calcareous microfossils such as foraminifera contained in deep sea cores. The North Pacific Ocean borders the Asian and North We review here the late Pleistocene (25,000-10,000 American continents along an intricate coastline arcing BP) and Holocene (10,000-O BP) paleoclimate and between Japan and California (Fig. 1). Unlike the paleogeography of the coastal regions bordering the Atlantic Ocean, the North Pacific is virtually barred from North Pacific from northern Japan, through Alaska, and the Arctic Ocean, being connected only through the down the northwest coast of North America through shallow and narrow Bering Strait. Across this strait and British Columbia into Washington state. Emphasis is surrounding parts of the Bering Platform, the fauna and placed on coastal areas of Alaska, the areas we know flora of Asia and North America have mingled. By this best. All ages are expressed as uncalibrated radiocarbon route, humans probably first entered the New World years before present. (Meltzer, 1993). Biotic interchange between continents is The reader is cautioned that the wide geographical one reason why the paleoclimates and paleogeography of separation of data sites introduces assumptions about spa- the North Pacific coastline are of special interest. tial scales into the paleogeographic reconstructions we Another reason is that, like the North Atlantic, the North present. As the distance between data sites increases, so Pacific greatly affects the climate and weather over the does the uncertainty in the reconstructed image of the surrounding landmasses, especially downwind in North paleolandscape. The patch size relevant to an organism, America (e.g. Charles et al., 1994). Past and future whether human or spruce tree, can be far smaller than the climatic changes are intimately tied to oceanographic and resolution of our reconstructions. Scale problems also climatic processes in the Pacific Ocean. derive from the available temporal control since most Although the largest of the three major oceans, the studies rely on radiocarbon chronologies whose resolu- Pacific is poorly understood in terms of its late tions range from hundreds to thousands of years. Rates of Pleistocene history. This lack of information is especially climatic or geographic changes, which may have been notable in the Russian sectors of the coast. critical in determining species survival or extinction, Paleoceanographic research has lagged in the North generally are inadequately known at present. Pacific because the carbonate-compensation depth, the water depth where calcareous microfossils dissolve, is THE NORTHWEST PACIFIC OCEAN above the bottom over large reaches of this deep ocean (Archer and Maier-Reimer, 1994). In other oceans, most The northwest Pacific Ocean stretches from Hokkaido notably in the North Atlantic, our reconstructions of pale- to the Commander Islands and includes the Sea of oceanography and paleotemperature are largely based on Okhotsk and the Sea of Japan (Fig. 1). Today this sector 449 450 Quaternary Science Reviews: Volume 14 FIG. 1. North Pacific region, showing landmasses, continental shelves (light grey), and major ocean currents (arrows). The Tsushima Current flows northward through the Sea of Japan and into the Pacific Ocean through Tsugaru Strait south of Hokkaido. of the Pacific, lying beneath the shifting border between summer, and allowing surface waters to warm in summer cool Siberian air masses and warmer maritime air, is the (L.E. Heusser and Morley, 1985). Boreal-forest vegeta- birthplace of many of the cyclonic storms that travel to tion dominated by Picea, Abies, Tsuga and Pinus spread the North American coastline along the prevailing west- downslope and southward to cover most of the Japanese erlies (Wendland and Bryson, 1981; Terada and archipelago (Tsukada, 1983, 1985). Mean annual temper- Hanzawa, 1984). Hence the paleoclimatology of this atures in the northern archipelago may have been as region is of key interest in understanding the climatic his- much as 8-9OC below present values and mean annual tory of other sectors of the North Pacific coastline. precipitation may have been one-third lower during the Paleoclimatic events before 15,000 BP are poorly LGM (Tsukada, 1986; Kerschner, 1987; Morley and understood in the northwest Pacific. During the last Heusser, 1989). Temperatures and precipitations predict- glacial maximum (LGM), the Polar Front was displaced ed by global circulation modeling for the LGM in this perhaps 5” of latitude further south (CLIMAP, 198 1; region have similar signs and magnitudes as estimates Morley and Heusser, 1989). Steepening of temperature based on the field data (Winkler and Wang, 1993). gradients along the coast of northeastern Asia probably In northeastern Siberia during the LGM, subpolar caused an intensification of wind speeds at the 500 mb desert and montane tundra (Grichuk, 1984) covered the level and a more zonal orientation of the subpolar jet lowlands between mountain massifs supporting isolated stream (Kutzbach et al., 1993). The Japanese archipelago ice caps and valley glaciers (Glushkova, 1994). Open was much cooler and drier than today as maritime air forests of spruce and birch grew on the southern tip of masses were displaced south and eastwards and replaced Kamchatka and in the Amur River region (Fig. 2). At the by the Siberian High for much of the year (Morley and same time, the upper Kolyma River valley supported Heusser, 1989; Winkler and Wang, 1993). With lowered Arremisia-Gramineae tundra growing on poorly-devel- sea level, Japan was connected to the Asian mainland. oped, frost-disturbed soils (Lozhkin et al., 1993). Seasonal temperature contrasts were greater than today, The first indications of climatic amelioration in the probably because low-salinity surface waters stabilized upper Kolyma valley occurred ca. 12,500-12,000 BP the water column, preventing deep convection in with a transition from herb tundra to Betula shrub-tundra D.H. Mann and T.D. Hamilton: Paleotinvironments of the North Pacific Coast 451 i/ 60°N- Sea ‘Kamchatka fl\-1’00 m bathymetric FIG. 2. Vegetation zones of northeast Asia during the last glacial maximum (LGM) ca. 22,000-18,000 BP as inferred by Grichuk (1984). Heavy lines depict modem coastline; black areas represent glaciers. (Lozhkin et al., 1993). Larix duhurica forests became A possible late Glacial cold episode analogous to the established ca. 11,600 BP indicating summer tempera- Younger Dryas in the North Atlantic is currently a topic tures of at least 12°C. The last major element of the mod- of active research in the northwest Pacific. Chinzei et al. em vegetation to arrive, the stone pine (Pinus pumilu), (1987) and Kallel et al. (1988) interpret isotope and reached the upper Kolyma River about 9000 BP. The foraminifera data to indicate a re-advance of subpoiar autecology of this conifer implies an amelioration in win- water along the Japanese coast between 11,000 and ter conditions that may have included deeper snow packs 10,000 BP, correlative with the re-advance of the polar and warmer temperatures (Lozhkin et al., 1993). Pollen front in the North Atlantic during the Younger Dryas. A accumulation rates suggest that altitudinal treeline may Younger Dryas signal may be present in the Chinese have risen in the Kolyma area between 9000 and 7000 loess record (An et al., 1993) and possibly in pollen BP (Lozhkin et al., 1993) accompanying a northward records near Beijing (Liu, 1988). However, Keigwin and advance in latitudinal treeline on the Kolyma plain (Kind, Gorbarenko (1992) ascribe possible Younger Dryas 1967). analogs near northern Japan to an episode of freshwater Deep-sea sediment records indicate that full-glacial discharge from the Sea of Japan. conditions persisted in the northwest Pacific Ocean until During the early Holocene, sea-surface temperatures ca. 14,000-13,000 BP, when the first of three abrupt were 1-4”C lower than today (L.E. Heusser and Morley, changes in water temperature and/or salinity occurred 1990).
Load more

Recommended publications
  • PICES Sci. Rep. No. 2, 1995
    TABLE OF CONTENTS Page FOREWORD vii Part 1. GENERAL INTRODUCTION AND RECOMMENDATIONS 1.0 RECOMMENDATIONS FOR INTERNATIONAL COOPERATION IN THE OKHOTSK SEA AND KURIL REGION 3 1.1 Okhotsk Sea water mass modification 3 1.1.1Dense shelf water formation in the northwestern Okhotsk Sea 3 1.1.2Soya Current study 4 1.1.3East Sakhalin Current and anticyclonic Kuril Basin flow 4 1.1.4West Kamchatka Current 5 1.1.5Tides and sea level in the Okhotsk Sea 5 1.2 Influence of Okhotsk Sea waters on the subarctic Pacific and Oyashio 6 1.2.1Kuril Island strait transports (Bussol', Kruzenshtern and shallower straits) 6 1.2.2Kuril region currents: the East Kamchatka Current, the Oyashio and large eddies 7 1.2.3NPIW transport and formation rate in the Mixed Water Region 7 1.3 Sea ice analysis and forecasting 8 2.0 PHYSICAL OCEANOGRAPHIC OBSERVATIONS 9 2.1 Hydrographic observations (bottle and CTD) 9 2.2 Direct current observations in the Okhotsk and Kuril region 11 2.3 Sea level measurements 12 2.4 Sea ice observations 12 2.5 Satellite observations 12 Part 2. REVIEW OF OCEANOGRAPHY OF THE OKHOTSK SEA AND OYASHIO REGION 15 1.0 GEOGRAPHY AND PECULIARITIES OF THE OKHOTSK SEA 16 2.0 SEA ICE IN THE OKHOTSK SEA 17 2.1 Sea ice observations in the Okhotsk Sea 17 2.2 Ease of ice formation in the Okhotsk Sea 17 2.3 Seasonal and interannual variations of sea ice extent 19 2.3.1Gross features of the seasonal variation in the Okhotsk Sea 19 2.3.2Sea ice thickness 19 2.3.3Polynyas and open water 19 2.3.4Interannual variability 20 2.4 Sea ice off the coast of Hokkaido 21
    [Show full text]
  • Oceanographic Structure in the Bering Sea
    Title OCEANOGRAPHIC STRUCTURE IN THE BERING SEA Author(s) OHTANI, Kiyotaka Citation MEMOIRS OF THE FACULTY OF FISHERIES HOKKAIDO UNIVERSITY, 21(1), 65-106 Issue Date 1973-10 Doc URL http://hdl.handle.net/2115/21855 Type bulletin (article) File Information 21(1)_P65-106.pdf Instructions for use Hokkaido University Collection of Scholarly and Academic Papers : HUSCAP OCEANOGRAPHIC STRUCTURE IN THE BERING SEA Kiyotaka OHTANI Faculty of Fisherie8, Hokkaido Univer8ity, Hakodate, Japan Contents 1. Introduction ..•••••....•.•.•...•.•••••.....•.••.•.•.•..••......... 65 1. Preface ...................................................... 65 2. Subarctic region ............................................. 66 3. Sources of data . .. 67 4. Bottom configuration ............................................ 68 II. Waters Coming into the Bering Sea from the Pacific Ocean .............. 70 ill. Current Pattern in the Bering Sea . .. 73 IV. Waters in the Bering Sea Basin . .. 76 1. Vertical structure of the basin water ..... .. .. .. .. .. .. .. .. .. ... 76 2. Types of vertical distribution of salinity and temperature .. .. 81 3. Process of formation of various Types .............................. 82 V. Waters on the Continental Shelf ...................................... 85 1. Horizontal distribution of salinity and temperature ............... 85 2. Vertical section ............................................... 91 3. Classification to type of vertical structure ....................... 94 VI. Interaction between the Shelf Waters and the Basin Waters
    [Show full text]
  • Fronts in the World Ocean's Large Marine Ecosystems. ICES CM 2007
    - 1 - This paper can be freely cited without prior reference to the authors International Council ICES CM 2007/D:21 for the Exploration Theme Session D: Comparative Marine Ecosystem of the Sea (ICES) Structure and Function: Descriptors and Characteristics Fronts in the World Ocean’s Large Marine Ecosystems Igor M. Belkin and Peter C. Cornillon Abstract. Oceanic fronts shape marine ecosystems; therefore front mapping and characterization is one of the most important aspects of physical oceanography. Here we report on the first effort to map and describe all major fronts in the World Ocean’s Large Marine Ecosystems (LMEs). Apart from a geographical review, these fronts are classified according to their origin and physical mechanisms that maintain them. This first-ever zero-order pattern of the LME fronts is based on a unique global frontal data base assembled at the University of Rhode Island. Thermal fronts were automatically derived from 12 years (1985-1996) of twice-daily satellite 9-km resolution global AVHRR SST fields with the Cayula-Cornillon front detection algorithm. These frontal maps serve as guidance in using hydrographic data to explore subsurface thermohaline fronts, whose surface thermal signatures have been mapped from space. Our most recent study of chlorophyll fronts in the Northwest Atlantic from high-resolution 1-km data (Belkin and O’Reilly, 2007) revealed a close spatial association between chlorophyll fronts and SST fronts, suggesting causative links between these two types of fronts. Keywords: Fronts; Large Marine Ecosystems; World Ocean; sea surface temperature. Igor M. Belkin: Graduate School of Oceanography, University of Rhode Island, 215 South Ferry Road, Narragansett, Rhode Island 02882, USA [tel.: +1 401 874 6533, fax: +1 874 6728, email: [email protected]].
    [Show full text]
  • Effect of Pleistocene Glaciation Upon Oceanographic Characteristics of the North Pacific Ocean and Bering Sea
    Deep-Sea Research, Vol. 30, No. 8A, pp. 851 to 869, 1983. 0198-0149/83 $3.00 + 0.00 Printed in Great Britain. (c) 1983 Pergamon Press Ltd. Effect of Pleistocene glaciation upon oceanographic characteristics of the North Pacific Ocean and Bering Sea CONSTANCE SANCETTA* (Received 23 October 1982; in revisedform 28 January 1983; accepted 28 April 1983) Abstract--During intervals of Pleistocene glaciation, insolation of the high-latitude northern hemisphere was lower than today, particularly during summer. Growth of continental ice sheets resulted in a lowering of sea level by more than 100 m in the Bering Sea. As a result, the Bering Strait was closed and most of the Bering continental shelf exposed. A proposed model predicts that (1) sea-ice formation would occur along the (modern) outer continental shelf, (2)advection would transport the sea ice over the deep basin, and (3) brine would flow into the basin at some inter- mediate depth to enhance the halocline. The result would be a low-salinity surface layer with a cold, thick halocline and reduced vertical mixing. Diatom microfossils and lithologic changes in sediment cores from the North Pacific Ocean and Bering Sea support the model and suggest that the proposed oceanographic conditions extended into the North Pacific, where the cold low-salinity laycr was enhanced by meltwater from continentally derived icebergs. INTRODUCTION IN THE last decade, marine geologists have begun to make observations and interpretations bearing on the physical oceanography and climate of the earth in the past (e.g., CLIMAP, 1976; Coauss, 1979; KEIGWIN, BENDER and KENNETT, 1979).
    [Show full text]
  • Numerical Study on the Oyashio Water Pathways in the Kuroshio±Oyashio Con¯Uence*
    1174 JOURNAL OF PHYSICAL OCEANOGRAPHY VOLUME 34 Numerical Study on the Oyashio Water Pathways in the Kuroshio±Oyashio Con¯uence* HUMIO MITSUDERA,1,11 BUNMEI TAGUCHI,# YASUSHI YOSHIKAWA,@ HIROHIKO NAKAMURA,& TAKUJI WASEDA,1 AND TANGDONG QU** 1FRSGC, Yokohama, Japan, and IPRC, SOEST, University of Hawaii, Honolulu, Hawaii #Department of Meteorology, SOEST, University of Hawaii, Honolulu, Hawaii @Japan Marine Science and Technology Center, Yokosuka, Japan &Fisheries Department, Kagoshima University, Kagoshima, Japan **IPRC, SOEST, University of Hawaii, Honolulu, Hawaii 11ILTS, Hokkaido University, Sapporo, Japan (Manuscript received 21 October 2002, in ®nal form 3 September 2003) ABSTRACT In this paper, results of a high-resolution regional model of the Kuroshio±Oyashio con¯uence, where the mixed water region (MWR) forms off the northeastern coast of Japan, are discussed. The model simulates major characteristics of the Kuroshio and the Oyashio system well, such as the separation of the Kuroshio Extension from the Japanese coast and southward intrusion of the Oyashio. Further, potential temperature and salinity structures in the intermediate layer su 5 27.0 resemble those obtained from historical data. Upon the success of this simulation, the authors focus on the diagnosis of the Oyashio water pathways intruding into the subtropics. It is found that the pathways of the Oyashio water form in the vicinity of the Japanese coast, where warm core rings and the Oyashio intrusion are active. These pathways are shown to be primarily eddy driven. Of particular interest is the water that originates in the Sea of Okhotsk, characterized by low potential vorticity (PV). Impacts of the Okhotsk water are identi®ed by conducting an experiment in which the exchange of waters between the Paci®c Ocean and the Sea of Okhotsk is blocked.
    [Show full text]
  • Late Quaternary Changes in Intermediate Water Oxygenation And
    PALEOCEANOGRAPHY, VOL. 22, PA3213, doi:10.1029/2005PA001234, 2007 Late Quaternary changes in intermediate water oxygenation and oxygen minimum zone, northern Japan: A benthic foraminiferal perspective Akihiko Shibahara,1 Ken’ichi Ohkushi,2 James P. Kennett,3 and Ken Ikehara4 Received 20 October 2005; revised 20 May 2007; accepted 8 June 2007; published 24 August 2007. [1] A strong oxygen minimum zone (OMZ) currently exists at upper intermediate water depths on the northern Japanese margin, NW Pacific. The OMZ results largely from a combination of high surface water productivity and poor ventilation of upper intermediate waters. We investigated late Quaternary history (last 34 kyr) of ocean floor oxygenation and the OMZ using quantitative changes in benthic foraminiferal assemblages in three sediment cores taken from the continental slope off Shimokita Peninsula and Tokachi, northern Japan, at water depths between 975 and 1363 m. These cores are well located within the present-day OMZ, a region of high surface water productivity, and in close proximity to the source region of North Pacific Intermediate Water. Late Quaternary benthic foraminiferal assemblages experienced major changes in response to changes in dissolved oxygen concentration in ocean floor sediments. Foraminiferal assemblages are interpreted to represent three main groups representing oxic, suboxic, and dysoxic conditions. Assemblage changes in all three cores and hence in bottom water oxygenation coincided with late Quaternary climatic episodes, similar to that known for the southern California margin. These episodes, in turn, are correlated with orbital and millennial climate episodes in the Greenland ice core including the last glacial episode, Bølling-A˚ llerød (B/A), Younger Dryas, Preboreal (earliest Holocene), early Holocene, and late Holocene.
    [Show full text]
  • Alaska Exclusive Economic Zone: Ocean Exploration and Research Bibliography
    Alaska Exclusive Economic Zone: Ocean Exploration and Research Bibliography Hope Shinn, Librarian, NOAA Central Library Jamie Roberts, Librarian, NOAA Central Library NCRL subject guide 2020-08 doi: 10.25923/k182-6s39 September 2020 U.S. Department of Commerce National Oceanic and Atmospheric Administration Office of Oceanic and Atmospheric Research NOAA Central Library – Silver Spring, Maryland Table of Contents Background ............................................................................................................................................... 3 Scope ......................................................................................................................................................... 3 Sources Reviewed ..................................................................................................................................... 7 Acknowledgements ................................................................................................................................... 7 Section I: Aleutian Islands ......................................................................................................................... 8 Section II: Aleutian Islands, Beaufort Sea, Bering Sea, Chukchi Sea, Gulf of Alaska ............................... 26 Section III: Aleutian Islands, Bering Sea, Gulf of Alaska .......................................................................... 27 Section IV: Aleutian Islands, Central Gulf of Alaska ...............................................................................
    [Show full text]
  • Characteristics of Mesoscale Eddies in the Kuroshio–Oyashio Extension Region Detected from the Distribution of the Sea Surface Height Anomaly
    1018 JOURNAL OF PHYSICAL OCEANOGRAPHY VOLUME 40 Characteristics of Mesoscale Eddies in the Kuroshio–Oyashio Extension Region Detected from the Distribution of the Sea Surface Height Anomaly SACHIHIKO ITOH AND ICHIRO YASUDA Ocean Research Institute, University of Tokyo, Tokyo, Japan (Manuscript received 2 April 2009, in final form 28 September 2009) ABSTRACT This study investigates the distribution of the sea surface height anomaly (SSHA) with the aim of quan- tifying the characteristics of mesoscale eddies in the Kuroshio–Oyashio extension region (KOER), where intense mesoscale eddies are commonly observed during hydrographic surveys. Dense distributions of both anticyclonic eddies (AEs) and cyclonic eddies (CEs) are detected for the first time in KOER with sufficient temporal and spatial coverage, using the Okubo–Weiss parameter without smoothing. Their contribution to the total SSHA variance is estimated to be about 50%. The zones of highest amplitudes are located north and south of the axis of the Kuroshio Extension (KE) for AEs and CEs, which represent warm-core and cold-core rings, respectively; the areas extend poleward along the Japan and Kuril–Kamchatka Trenches, especially for AEs. Eddies of both polarities and with moderate amplitudes are also recognized along the Subarctic Front (SAF). Eddies in areas north and south of the KE generally propagate westward, at a mean rate of 1–5 cm s21; those along the trenches south of 468N and along the SAF propagate poleward at mean rates of 1–2 and 0.5–1 cm s21, respectively. Because of the asymmetric distribution of the AEs and CEs in the areas north and south of the KE, and the asymmetric amplitude of them along the Japan and Kuril–Kamchatka Trenches, there exist significant eddy fluxes of vorticity, heat, and salinity in these areas.
    [Show full text]
  • Component 2, Part 1 Centripetal Forces in Japan: the Physical Setting the Japanese Archipelago Consists of Four Major Islands and Numerous Smaller Islands
    Component 2, Part 1 Centripetal Forces in Japan: The Physical Setting The Japanese archipelago consists of four major islands and numerous smaller islands. The archipelago is separated from the Asian mainland by the Sea of Okhorsk, the Sea of Japan, and the East China Sea (Figure 1). Japan is the "Land of the Rising Sun" as depicted on the Japanese flag (Figure 2). Because this is an island nation there have historically been strong physical barriers to migration. Not only are there three seas to the west, but there is the expanse of the Pacific Ocean to the east. The strong, warm Kuroshio Ocean current travels northward along the east coast of Japan. The cold Oyashio current flows south along the coast of Asia. The Oyashio meets the Kuroshio off the east coast and fogs develop along the boundary between the currents. The cold, foggy condition known as yamase can occur from June to mid-August in northern Japan adding localized climatic barriers. Japan's Neolithic people, the Jomon Culture (ca. 10,000 BCE - ca. 300 BCE) used the marine and coastal resources (Karan, 2005). Japan extends across 24 degrees of latitude, which would be similar to going from Boston to Mexico City in North America. This expanse, plus the climatic variations and the insular and ocean current factors limiting access, accounted for some of the isolation and separate development. It was during the Yayoi Period (ca. 300 BCE - ca. 300 CE) that Mongoloid immigrants crossed the Strait of Tsushima separating Japan from the Korean Peninsula in significant numbers bringing the knowledge of rice paddy cultivation, weaving, and smelting of iron.
    [Show full text]
  • Influences of the Kuroshio/Oyashio Extensions on Air–Sea Heat
    6536 JOURNAL OF CLIMATE VOLUME 22 Influences of the Kuroshio/Oyashio Extensions on Air–Sea Heat Exchanges and Storm-Track Activity as Revealed in Regional Atmospheric Model Simulations for the 2003/04 Cold Season* BUNMEI TAGUCHI Earth Simulator Center, JAMSTEC, Yokohama, Japan HISASHI NAKAMURA Department of Earth and Planetary Science, University of Tokyo, Tokyo, and Research Institute for Global Change, JAMSTEC, Yokohama, Japan MASAMI NONAKA Research Institute for Global Change, JAMSTEC, Yokohama, Japan SHANG-PING XIE IPRC, and Department of Meteorology, SOEST, University of Hawaii at Manoa, Honolulu, Hawaii (Manuscript received 30 October 2008, in final form 8 July 2009) ABSTRACT Influences of oceanic fronts in the Kuroshio and Oyashio Extension (KOE) region on the overlying at- mosphere are investigated by comparing a pair of atmospheric regional model hindcast experiments for the 2003/04 cold season, one with the observed finescale frontal structures in sea surface temperature (SST) prescribed at the model lower boundary and the other with an artificially smoothed SST distribution. The comparison reveals the locally enhanced meridional gradient of turbulent fluxes of heat and moisture and surface air temperature (SAT) across the oceanic frontal zone, which favors the storm-track development both in winter and spring. Distinct seasonal dependency is found, however, in how dominantly the storm-track activity influences the time-mean distribution of the heat and moisture supply from the ocean. In spring the mean surface sensible heat flux (SHF) is upward (downward) on the warmer (cooler) side of the subarctic SST front. This sharp cross-frontal contrast is a manifestation of intermittent heat release (cooling) induced by cool northerlies (warm southerlies) on the warmer (cooler) side of the front in associ- ation with migratory cyclones and anticyclones.
    [Show full text]
  • Book 31 Oyashio Current.Indb
    (MPCBM*OUFSOBUJPOBM 8BUFST"TTFTTNFOU 0ZBTIJP$VSSFOU (*8"3FHJPOBMBTTFTTNFOU "MFLTFFW "7 ,ISBQDIFOLPW '' #BLMBOPW 1+ #MJOPW :( ,BDIVS "/ .FEWFEFWB *" .JOBLJS 1"BOE(%5JUPWB Global International Waters Assessment Regional assessments Other reports in this series: Russian Arctic – GIWA Regional assessment 1a Caribbean Sea/Small Islands – GIWA Regional assessment 3a Caribbean Islands – GIWA Regional assessment 4 Barents Sea – GIWA Regional assessment 11 Baltic Sea – GIWA Regional assessment 17 Caspian Sea – GIWA Regional assessment 23 Aral Sea – GIWA Regional assessment 24 Gulf of California/Colorado River Basin – GIWA Regional assessment 27 Yellow Sea – GIWA Regional assessment 34 East China Sea – GIWA Regional assessment 36 Patagonian Shelf – GIWA Regional assessment 38 Brazil Current – GIWA Regional assessment 39 Amazon Basin – GIWA Regional assessment 40b Canary Current – GIWA Regional assessment 41 Guinea Current – GIWA Regional assessment 42 Lake Chad Basin – GIWA Regional assessment 43 Benguela Current – GIWA Regional assessment 44 Indian Ocean Islands – GIWA Regional assessment 45b East African Rift Valley Lakes – GIWA Regional assessment 47 South China Sea – GIWA Regional assessment 54 Mekong River – GIWA Regional assessment 55 Sulu-Celebes (Sulawesi) Sea – GIWA Regional assessment 56 Indonesian Seas – GIWA Regional assessment 57 Pacifi c Islands – GIWA Regional assessment 62 Humboldt Current – GIWA Regional assessment 64 Global International Waters Assessment Regional assessment 31 Oyashio Current GIWA report production Series editor:
    [Show full text]
  • Oyashio Current: LME #51
    X North West Pacific 403 X-24 Oyashio Current: LME #51 S. Heileman and I. Belkin The Oyashio Current LME is located in the northwest Pacific Ocean and is bordered by Russia (the Kamchatka Peninsula and Kuril Islands) and the Japanese island of Hokkaido. It covers an area of about 530,000 km2, of which 0.19% is protected, and contains 0.09% of the world’s sea mounts (Sea Around Us 2007). A sub-arctic climate characterises this LME, which is based on the distinctive cold Oyashio Current (or the Kuril Current) with its strong interannual variations in strength (Minoda 1989). The geographic remoteness and inaccessibility of the Kuril Islands, combined with the extreme environmental conditions have discouraged human settlement and contributed to making the Kuril Archipelago one of the least known regions of the world. The 2,000 km Kuril-Kamchatka island arc is part of the ‘Ring of Fire’, a chain of volcanoes encircling the Pacific Ocean (Simkin & Siebert 1994). Accounts pertaining to this LME include Minoda (1989) and UNEP (2006). I. Productivity The Oyashio Current LME is a Class II, moderately productive (150-300 gCm-2y-1) ecosystem (Figure X-24.3). The confluence zone of the cold Oyashio Current and the warm Kuroshio Current off northern Japan gives rise to some of the most productive marine areas of East Asia, with many species of fauna and flora and rich fishing grounds. The phytoplankton has ‘traditional’ spring bloom dynamics (Kasai et al. 1997) leading to a typical phytoplankton-macrozooplankton-fish food web. It is believed that the high zooplankton biomass depends on the cold waters of the Oyashio Current below the thermocline (Minoda 1989).
    [Show full text]