新着論文紹介 This Week's New Paper (2012/4/10) AGU, EGU, GSA

☆Geophysical Research Letters☆ 2012/4/2-8

1.    A reassessment of lake and wetland feedbacks on the North African Holocene climate

Krinner, G., A.-M. Lézine, P. Braconnot, P. Sepulchre, G. Ramstein, C. Grenier, and I. Gouttevin (2012)

Geophys. Res. Lett., 39, L07701, doi:10.1029/2012GL050992.

・Open-water surfaces lead to increased precipitation rates in North Africa

・This provides a major positive feedback to the mid-Holocene

・Climate models should take this effect into account

→前中期完新世の北アフリカのサハラで、湖や湿地による降水量へのフィードバックを気候モデルで調べると、かなり大きく、地域的には降水量を2倍以上にするらしい。“緑のサハラ”が実現可能？

2.    The Arctic Ocean warms from below

Carmack, E. C., W. J. Williams, S. L. Zimmermann, and F. A. McLaughlin (2012)

Geophys. Res. Lett., 39, L07604, doi:10.1029/2012GL050890.

・The deep water is warming at a measurable rate of ~0.0004 deg C yr-1

・This heating is not escaping along the basin perimeter

・A greater fraction of the heat escapes vertically than previously thought

→北極海のCanada Basin深層水（CBDW）が1993-2010年の間に地熱により温暖化していて、鉛直方向に熱が伝わっているらしい。

3.    Properties of deep convection in tropical continental, monsoon, and oceanic rainfall regimes

Xu, W. and E. J. Zipser (2012)

Geophys. Res. Lett., 39, L07802, doi:10.1029/2012GL051242.

・Clear regime separation exists among continent, monsoon, and oceanic convection

・Regime variations are most evident in mixed-phase precipitation processes

・Monsoon actives (breaks) are slightly more continental (oceanic) in nature

☆Geochemistry Geophysics Geosystems (G3)☆ 2012/4/2-8

4.    Characterizing the microstructure of Arctica islandica shells using NanoSIMS and EBSD

Karney, G. B., P. G. Butler, S. Speller, J. D. Scourse, C. A. Richardson, M. Schröder, G. M. Hughes, J. T. Czernuszka, and C. R. M. Grovenor (2012)

Geochem. Geophys. Geosyst., 13, Q04002, doi:10.1029/2011GC003961.

・The two annual increments in A. islandica shell are compositionally distinct

・Orientation of the aragonite c-axis is the same in both annual increments

・The aragonite a- and b- axes are oriented at three preferred angles

→アイスランドガイ（400年くらい生きるらしい）の貝殻微細構造をNanoSIMSとEBSDで調べた。

☆Global Biogeochemical Cycles☆ 2012/4/2-8

5.    Contribution of tropical cyclones to the air-sea CO2 flux: A global view

Lévy, M., M. Lengaigne, L. Bopp, E. M. Vincent, G. Madec, C. Ethé, D. Kumar, and V. V. S. S. Sarma (2012)

Global Biogeochem. Cycles, 26, GB2001, doi:10.1029/2011GB004145.

・Very weak contribution of hurricanes to global air-sea CO2 flux

・Global simulation of ocean carbon cycle response to 10 yrs of tropical cyclones

・Compensation between effects on gas transfer coefficient and on CO2 solubility

→熱帯サイクロンが大気海洋CO2フラックスに与える影響を、最深の海洋生物地球化学モデルで評価したら、従来の推定より1桁か2桁小さく、全球的には寄与はかなり小さいらしい。

☆Journal of Geophysical Research - Atmosphere☆ 2012/4/2-8

6.    Sun-Moon gravitation-induced wave characteristics and climate variation

Wang, Z., D. Wu, X. Song, X. Chen, and S. Nicholls (2012)

J. Geophys. Res., 117, D07102, doi:10.1029/2011JD016967.

・Sun-Moon gravitation drives nonlinear motions of geophysical fluids

・The motions demonstrate the climate variations with abundant periods

・Earth's rotation helps fluids remember and accumulate momentum on multiple time scales

→太陽と月の重力による流体の動きが気候に与える影響。30-60日周期やENSOなどとの関係。

☆Journal of Geophysical Research - Oceans☆ 2012/4/2-8

7.    Rhizoplegma boreale (Radiolaria): A tracer for mesoscale eddies from coastal areas

Ikenoue, T., H. Ueno, and K. Takahashi (2012)

J. Geophys. Res., 117, C04001, doi:10.1029/2011JC007728.

・Rhizoplegma boreale (Radiolaria) is a new biological tracer for mesoscale eddies

・Coastal signals are brought out to the deep-sea region by the mesoscale eddies

・Long-term monitoring of sinking particle fluxes and influential eddies

→放散虫R. borealeが海洋のメソスケール渦の指標になる？　セディメントトラップや衛星データの解析によると、メソスケール渦が沿岸の富栄養な海水を遠洋に運び、放散虫の生産性に影響するらしい。

8.    Sea surface chlorophyll signature in the tropical Pacific during eastern and central Pacific ENSO events

Radenac, M.-H., F. Léger, A. Singh, and T. Delcroix (2012)

J. Geophys. Res., 117, C04007, doi:10.1029/2011JC007841.

・Specific surface chlorophyll signature during Central Pacific El Nino

・Advection of warm pool oligotrophic water to the central equatorial Pacific

・Westward surface current limits the extension of chlorophyll poor waters

→中央太平洋タイプENSOが熱帯太平洋の生物生産（海洋表層クロロフィル）に与える影響。

9.    Primary productivity, new productivity, and their relation to carbon flux during two Southern Ocean Gas Exchange tracer experiments

Lance, V. P., P. G. Strutton, R. D. Vaillancourt, B. R. Hargreaves, J.-Z. Zhang, and J. Marra (2012)

J. Geophys. Res., 117, C00F14, doi:10.1029/2011JC007687.

・Primary and NO3- production likely regulated by silicic acid in SO GasEx Patch 1

・Primary and NO3- production likely influenced by ammonium in SO GasEx Patch 2

・Phytoplankton assemblage/physiology is consistent with some but not all parameters

→南大洋の大西洋セクターで、一次生産速度と新生産速度を同位体トレーサー実験で調べた。それぞれケイ酸とアンモニアに影響されている？　南大洋の混合層の炭素収支を考える上で重要らしい。

☆Journal of Geophysical Research – Space Physics☆ 2012/4/2-8

10.  Cyclic loss of open solar flux since 1868: The link to heliospheric current sheet tilt and implications for the Maunder Minimum

Owens, M. J., and M. Lockwood (2012)

J. Geophys. Res., 117, A04102, doi:10.1029/2011JA017193.

・Open solar flux loss is cyclic

・HCS tilt controls open solar flux loss

・Maunder Minimum HCS tilt and CME rates were similar to modern cycles

→太陽圏カレントシートの傾きがOpen solar flux lossを決めていて、OSF lossは概ね太陽黒点数と一致して周期を見せるけど、振幅や波形は驚くほど一定。マウンダー極小期でも、太陽圏カレントシートの傾きは現在の太陽周期と同じだった？

11.  Stratospheric warmings and the geomagnetic lunar tide: 1958–2007

Yamazaki, Y., A. D. Richmond, and K. Yumoto (2012)

J. Geophys. Res., 117, A04301, doi:10.1029/2012JA017514.

・Comparison between stratospheric parameters and the geomagnetic lunar tide

・Analysis of long-term data for 1958-2007

・Significant changes in the geomagnetic lunar tide during SSWs

→地磁気の月潮汐が、成層圏突然昇温（SSW）イベントと良い相関を示す。

12.  Is there long-range memory in solar activity on timescales shorter than the sunspot period?

Rypdal, M., and K. Rypdal (2012)

J. Geophys. Res., 117, A04103, doi:10.1029/2011JA017283.

・We test the hypotheses of long-range memory in solar data

・We construct stochastic models for solar data

・Differences in scaling laws in different solar data are discovered

☆Paleoceanography☆ 2012/4/2-8

13.  Silicic acid biogeochemistry in the Gulf of California: Insights from sedimentary Si isotopes

Pichevin, L., R. S. Ganeshram, B. C. Reynolds, F. Prahl, T. F. Pedersen, R. Thunell, and E. L. McClymont (2012)

Paleoceanography, 27, PA2201, doi:10.1029/2011PA002237.

・Millennial-scale changes in silicic acid utilization

・Role of transient Fe limitation on Si cycling

・Role of upwelling strength on formation on marine silicon sink

→過去55kyrsのカリフォルニア湾堆積物のケイ素同位体組成。気候変動に伴う湧昇の強度によって、ケイ酸利用効率が変わったことを反映？　鉄制限との関連も議論。

14.  Sea-surface temperature records of Termination 1 in the Gulf of California: Challenges for seasonal and interannual analogues of tropical Pacific climate change

McClymont, E. L., R. S. Ganeshram, L. E. Pichevin, H. M. Talbot, B. E. van Dongen, R. C. Thunell, A. M. Haywood, J. S. Singarayer, and P. J. Valdes (2012)

Paleoceanography, 27, PA2202, doi:10.1029/2011PA002226.

・Rapid shifts in tropical Pacific SST and opal production during deglaciation

・Evolving upwelling intensity linked to ITCZ and Subtropical High positions

・Data/model comparison reveals challenges for application of modern analogues

→カリフォルニア湾堆積物（25-6ka）のアルケノンとTEX86でSST復元。ITCZや亜熱帯高気圧の位置が湧昇強度に影響？　プロキシ復元とGCMシミュレーションの比較も。

☆Climate of the Past☆ 2012/4/2-8

15.  Interpreting last glacial to Holocene dust changes at Talos Dome (East Antarctica): implications for atmospheric variations from regional to hemispheric scales

Albani, S., Delmonte, B., Maggi, V., Baroni, C., Petit, J.-R., Stenni, B., Mazzola, C., and Frezzotti, M.

Clim. Past, 8, 741-750, doi:10.5194/cp-8-741-2012, 2012.

→東南極Talos Domeアイスコアの過去22kyrのダスト記録。Dome Cのデータなどと比べて、大気循環の変動を議論。

16.  Monsoonal response to mid-holocene orbital forcing in a high resolution GCM

Bosmans, J. H. C., Drijfhout, S. S., Tuenter, E., Lourens, L. J., Hilgen, F. J., and Weber, S. L.

Clim. Past, 8, 723-740, doi:10.5194/cp-8-723-2012, 2012.

→中期完新世（6ka）の軌道要素が、両半球のモンスーン（北アフリカ、アジア、南アメリカ）に与える影響を高解像度GCM（EC-Earth）で評価。

17.  Assessing extreme droughts in Spain during 1750–1850 from rogation ceremonies

Domínguez-Castro, F., Ribera, P., García-Herrera, R., Vaquero, J. M., Barriendos, M., Cuadrat, J. M., and Moreno, J. M.

Clim. Past, 8, 705-722, doi:10.5194/cp-8-705-2012, 2012.

→キリスト教の祈祷儀式（？）の文書記録から、AD1750-1850におけるスペインの干ばつを復元。

☆Journal of Geophysical Research - Biogeosciences☆

☆Biogeoscience☆

特になし

☆Geological Society of America Bulletin☆

新着なし

担当：山口保彦（D3）