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Richardson, I. G. ; Berdichevsky, D. ; Desch, M. D. ; Farrugia, C. J. 2000
Solar-cycle variation of low density solar wind during more than three solar cycles
Geophys. Res. Lett. Vol. 27 , No. 23 , p. 3761 (2000GL000077)
keywords: 2111 Interplanetary physics; Ejecta, driver gases, and magnetic clouds 2162 Solar cycle variations (7536) 2164 Solar wind plasma
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Usmanov, Arcadi V. ; Goldstein, Melvyn L. ; Farrell, William M. 2000
A View of the Inner Heliosohere During the May 10-11, 1999 Low Density Anomaly
Geophys. Res. Lett. Vol. 27 , No. 23 , p. 3765 (2000GL000082)
keywords: 2134 Interplanetary physics; Interplantary magnetic fields 2162 Solar cycle variations (7536) 2164 Solar wind plasma 2169 Sources of the solar wind
Crooker, N. U. ; Shodhan, S. ; Gosling, J. T. ; Simmerer, J. ; Lepping, R. P. ; Steinberg, J. T. ; Kahler, S. W. 2000
Density extremes in the solar wind
Geophys. Res. Lett. Vol. 27 , No. 23 , p. 3769 (2000GL003788)
keywords: 2111 Interplanetary physics; Ejecta, driver gases, and magnetic clouds 2134 Interplantary magnetic fields 2162 Solar cycle variations (7536) 2164 Solar wind plasma
Farrugia, C. J. ; Singer, H. J. ; Evans, D. ; Berdichevsky, D. ; Scudder, J. D. ; Ogilvie, K. W. ; Fitzenreiter, R. J. ; Russell, C. T. 2000
Response of the equatorial and polar magnetosphere to the very tenuous solar wind on May 11, 1999
Geophys. Res. Lett. Vol. 27 , No. 23 , p. 3773 (2000GL003800)
keywords: 2164 Interplanetary physics; Solar wind plasma 2455 Ionosphere; Particle precipitation 2475 Polar cap ionosphere 2740 Magnetospheric physics; Magnetospheric configuration and dynamics
Ohtani, S. ; Newell, P. T. ; Takahashi, K. 2000
Dawn-dusk profile of field-aligned currents on May 11, 1999: A familiar pattern driven by an unusual cause
Geophys. Res. Lett. Vol. 27 , No. 23 , p. 3777 (2000GL003789)
keywords: 2708 Magnetospheric physics; Current systems (2409) 2716 Energetic particles, precipitating 2740 Magnetospheric configuration and dynamics 2784 Solar wind/magnetosphere interactions
Terasawa, T. ; Kasaba, Y. ; Tsubouchi, K. ; Mukai, T. ; Saito, Y. ; Frank, L. A. ; Paterson, W. R. ; Ackerson, K. ; Matsumoto, H. ; Kojima, H. ; Matsui, H. ; Larson, D. ; Lin, R. ; Phan, T. ; Steinberg, J. ; McComas, D ; Skoug, R. ; Fujimoto, M. ; Hoshino, M. ; Nishida, A. 2000
GEOTAIL observations of anomalously low density plasma in the magnetosheath
Geophys. Res. Lett. Vol. 27 , No. 23 , p. 3781 (2000GL000087)
keywords: 2164 Interplanetary physics; Solar wind plasma 2784 Magnetospheric physics; Solar wind/magnetosphere interactions
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Papitashvili, V. O. ; Clauer, C. R. ; Christiansen, F. ; Pilipenko, V. A. ; Popov, V. A. ; Rasmussen, O. ; Suchdeo, V. P. ; Watermann, J. F. 2000
Geomagnetic disturbances at high latitudes during very low solar wind density event
Geophys. Res. Lett. Vol. 27 , No. 23 , p. 3785 (2000GL000089)
keywords: 2475 Ionosphere; Polar cap ionosphere
Rostoker, Gordon 2000
Ground Magnetic Signatures of ULF and Substorm Activity During an Interval of Abnormally Weak Solar Wind on May 11, 1999
Geophys. Res. Lett. Vol. 27 , No. 23 , p. 3789 (2000GL003790)
keywords: 2704 Magnetospheric physics; Auroral phenomena (2407) 2708 Current systems (2409) 2752 MHD waves and instabilities 2788 Storms and substorms
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Rice, W. K. M. ; Zank, G. P. ; le Roux, J. A. 2000
An injection mechanism for shock waves of arbitrary obliquity
Geophys. Res. Lett. Vol. 27 , No. 23 , p. 3793 (2000GL000128)
keywords: 2152 Interplanetary physics; Pickup ions 7514 Solar physics, astrophysics, and astronomy; Energetic particles (2114) 7851 Space plasma physics; Shock waves
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O'Brien, T. P. ; McPherron, R. L. 2000
Evidence against an independent solar wind density driver of the terrestrial ring current
Geophys. Res. Lett. Vol. 27 , No. 23 , p. 3797 (2000GL012125)
keywords: 2764 Magnetospheric physics; Plasma sheet 2778 Ring current 2784 Solar wind/magnetosphere interactions 2788 Storms and substorms
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Chilson, Phillip B. ; Belova, Evgenia ; Rietveld, Michael T. ; Kirkwood, Sheila ; Hoppe, Ulf-Peter 2000
First artificially induced modulation of PMSE using the EISCAT heating facility
Geophys. Res. Lett. Vol. 27 , No. 23 , p. 3801 (2000GL011897)
keywords: 2403 Ionosphere; Active experiments 6929 Radio science; Ionospheric physics (2409) 6952 Radar atmospheric physics 6964 Radio wave propagation
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Demekhov, A. G. ; Trakhtengerts, V. Yu. ; Bösinger, T. 2000
Pc 1 Waves and Ionospheric Alfvén Resonator: Generation or Filtration?
Geophys. Res. Lett. Vol. 27 , No. 23 , p. 3805 (2000GL000126)
keywords: 2411 Ionosphere; Electric fields (2712)Electric fields (2712) 2487 Wave propagation (6934) 2736 Magnetospheric physics; Magnetosphere/ionosphere interactions 2772 Plasma waves and instabilities
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Troshichev, O. A. ; Lukianova, R. Yu. ; Papitashvili, V. O. ; Rich, F. J. ; Rasmussen, O. 2000
Polar cap index (PC) as a proxy for ionospheric electric field in the near-pole region
Geophys. Res. Lett. Vol. 27 , No. 23 , p. 3809 (2000GL003756)
keywords: 2411 Ionosphere; Electric fields (2712)Electric fields (2712) 2431 Ionosphere/magnetosphere interactions (2736) 2776 Magnetospheric physics; Polar cap phenomena 2784 Solar wind/magnetosphere interactions
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Innis, J. L. 2000
Deceleration of the high-latitude thermospheric wind by polar cap gravity waves
Geophys. Res. Lett. Vol. 27 , No. 23 , p. 3813 (2000GL012066)
keywords: 0358 Atmospheric composition and structure; Thermosphere--energy deposition 2487 Ionosphere; Wave propagation (6934) 2776 Magnetospheric physics; Polar cap phenomena 3369 Meteorology and atmospheric dynamics; Thermospheric dynamics (0358)
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Israelevich, P. L. ; Gombosi, T. I. ; Ershkovich, A. I. ; DeZeeuw, D. L. ; Powell, K. G. 2000
Magnetic field structure at the diamagnetic cavity boundary (numerical simulations)
Geophys. Res. Lett. Vol. 27 , No. 23 , p. 3817 (2000GL000110)
keywords: 6025 Planetology: comets and small bodies; Interactions with solar wind plasma and fields 6028 Ionospheres--structure and dynamics 6030 Magnetic fields and magnetism
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Rocken, Christian ; Johnson, James M. ; Braun, John J. ; Kawawa, Hiroshi ; Hatanaka, Yuki ; Imakiire, Tetsuro 2000
Improving GPS surveying with modeled ionospheric corrections
Geophys. Res. Lett. Vol. 27 , No. 23 , p. 3821 (2000GL012049)
keywords: 1243 Geodesy and gravity; Space geodetic surveys 1294 Instruments and techniques 2447 Ionosphere; Modeling and forecasting 2494 Instruments and techniques
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Horányi, M. ; Robertson, S. ; Smiley, B. ; Gumbel, J. ; Witt, G. ; Walch, B. 2000
Rocket-borne mesospheric measurement of heavy (m >>10 amu) charge carriers
Geophys. Res. Lett. Vol. 27 , No. 23 , p. 3825 (2000GL011433)
keywords: 0300 Atmospheric composition and structure 0394 Instruments and techniques
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Stenbaek-Nielsen, H. C. ; Moudry, D. R. ; Wescott, E. M. ; Sentman, D. D. ; Sâo Sabbas, F. T. 2000
Sprites and Possible Mesospheric Effects
Geophys. Res. Lett. Vol. 27 , No. 23 , p. 3829 (2000GL003827)
keywords: 0342 Atmospheric composition and structure; Middle atmosphere--energy deposition 1600 Global change (new category) 3324 Meteorology and atmospheric dynamics; Lightning
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Smirnova, E. I. ; Mareev, E. A. ; Chugunov, Yu. V. 2000
Modeling of lightning generated electric field transitional processes
Geophys. Res. Lett. Vol. 27 , No. 23 , p. 3833 (1999GL011158)
keywords: 3300 Atmospheric composition and structure 3304 Meteorology and atmospheric dynamics;Atmospheric electricity 3324 Lightning 3367 Theoretical modeling
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Avila, Eldo E. ; Pereyra, Rodolfo G. 2000
Charge transfer during crystal-rgrauple collisions for two different cloud droplet size distributions
Geophys. Res. Lett. Vol. 27 , No. 23 , p. 3837 (2000GL012302)
keywords: 1854 Hydrology; Precipitation (3354) 1863 Snow and ice (1827) 3304 Meteorology and atmospheric dynamics; Atmospheric electricity 3324 Lightning
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Galbally, Ian E. ; Bentley, Simon T. ; Meyer, C. P. (Mick) 2000
Mid-latitude marine boundary-layer ozone destruction at visible sunrise observed at Cape Grim, Tasmania, 41°S.
Geophys. Res. Lett. Vol. 27 , No. 23 , p. 3841 (1999GL010943)
keywords: 0317 Atmospheric composition and structure; Chemical kinetic and photochemical properties 0320 Cloud physics and chemistry 0368 Troposphere--constituent transport and chemistry
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Lee, A. M. ; Roscoe, H. K. ; Oltmans, S. 2000
Model and measurements show Antarctic ozone loss follows edge of polar night
Geophys. Res. Lett. Vol. 27 , No. 23 , p. 3845 (2000GL011441)
keywords: 0340 Atmospheric composition and structure; Middle atmosphere--composition and chemistry 0341 Middle atmosphere--constituent transport and chemistry (3334) 3349 Meteorology and atmospheric dynamics; Polar meteorology
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Custer, Thomas G. ; Kato, Shuji ; Fall, Ray ; Bierbaum, Veronica M. 2000
Negative ion mass spectrometry and the detection of carbonyls and HCN from clover
Geophys. Res. Lett. Vol. 27 , No. 23 , p. 3849 (2000GL011873)
keywords: 0300 Atmospheric composition and structure 0322 Constituent sources and sinks 0394 Instruments and techniques
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Wohlfrom, K.-H. ; Eichkorn, S. ; Arnold, F. ; Schulte, P. 2000
Massive Positive and Negative Ions in the Wake of a Jet Aircraft: Detection by a Novel Aircraft-based Large Ion Mass Spectrometer (LIOMAS)
Geophys. Res. Lett. Vol. 27 , No. 23 , p. 3853 (2000GL011974)
keywords: 0335 Atmospheric composition and structure; Ion chemistry of the atmosphere (2419, 2427) 0345 Pollution--urban and regional (0305) 0394 Instruments and techniques
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Waugh, Darryn W. ; Polvani, Lorenzo M. 2000
Climatology of Intrusions into the Tropical Upper Troposphere
Geophys. Res. Lett. Vol. 27 , No. 23 , p. 3857 (2000GL012250)
keywords: 0368 Atmospheric composition and structure; Troposphere--constituent transport and chemistry 1620 Global change (new category); Climate dynamics (3309) 3362 Meteorology and atmospheric dynamics; Stratosphere/troposphere interactions 3374 Tropical meteorology
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Kaufman, Yoram J. ; Holben, Brent N. ; Tanré, Didier ; Slutsker, Ilya ; Smirnov, Alexander ; Eck, Thomas F. 2000
Will aerosol measurements from Terra and Aqua polar orbiting satellites represent the daily aerosol abundance and properties?
Geophys. Res. Lett. Vol. 27 , No. 23 , p. 3861 (2000GL011968)
keywords: 0305 Atmospheric composition and structure; Aerosols and particles (0345, 4801) 0345 Pollution--urban and regional (0305) 1610 Global change (new category); Atmosphere (0315, 0325) 1640 Remote sensing
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Rudolph, J. ; Czuba, E. 2000
On the use of isotopic composition measurements of volatile organic compounds to determine the "photochemical age" of an air mass
Geophys. Res. Lett. Vol. 27 , No. 23 , p. 3865 (2000GL011385)
keywords: 0340 Atmospheric composition and structure; Middle atmosphere--composition and chemistry 0341 Middle atmosphere--constituent transport and chemistry (3334) 3349 Meteorology and atmospheric dynamics; Polar meteorology
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Callis, Linwood B. ; Natarajan, Murali ; Lambeth, James D. 2000
Calcilated upper stratospheric effects of solar uv flux and NOy variations during the 11-year solar cycle
Geophys. Res. Lett. Vol. 27 , No. 23 , p. 3869 (2000GL011622)
keywords: 0340 Atmospheric composition and structure; Middle atmosphere--composition and chemistry 0342 Middle atmosphere--energy deposition 7536 Solar physics, astrophysics, and astronomy; Solar activity cycle (2162)
Voigt, Christiane ; Tsias, Athanasios ; Dörnbrack, Andreas ; Meilinger, Stefanie ; Luo, Beiping ; Schreiner, Jochen ; Larsen, Niels ; Mauersberger, Konrad ; Peter, Thomas 2000
Non-equilibrium compositions of liquid polar stratospheric clouds in gravity waves
Geophys. Res. Lett. Vol. 27 , No. 23 , p. 3873 (2000GL012168)
keywords: 0305 Atmospheric composition and structure; Aerosols and particles (0345, 4801) 0320 Cloud physics and chemistry 0340 Middle atmosphere--composition and chemistry 1610 Global change (new category); Atmosphere (0315, 0325)
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Preusse, Peter ; Eckermann, Stephen D. ; Offermann, Dirk 2000
Comparison of Global Distributions of Zonal-Mean Gravity Wave Variance Inferred from Different Satellite Instruments
Geophys. Res. Lett. Vol. 27 , No. 23 , p. 3877 (2000GL011916)
keywords: 0342 Atmospheric composition and structure; Middle atmosphere--energy deposition 3360 Meteorology and atmospheric dynamics; Remote sensing 3384 Waves and tides
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Collins, J. M. ; Mason, I. M. 2000
Local environmental conditions related to seasonal tropical cyclone activity in the Northeast Pacific basin
Geophys. Res. Lett. Vol. 27 , No. 23 , p. 3881 (2000GL011614)
keywords: 3309 Meteorology and atmospheric dynamics; Climatology (1620) 3374 Tropical meteorology 3394 Instruments and techniques 9355 Information related to geographic region; Pacific Ocean
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Vuille, Mathias ; Bradley, Raymond S. 2000
Mean annual temperature trends and their vertical structure in the tropical Andes
Geophys. Res. Lett. Vol. 27 , No. 23 , p. 3885 (2000GL011871)
keywords: 1600 Global change (new category) 3374 Meteorology and atmospheric dynamics; Tropical meteorology 4522 Oceanography: physical; El Niño 9360 Information related to geographic region; South America
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Wilson, R. John 2000
Evidence for Diurnal Period Kelvin Waves in the Martian Atmosphere from Mars Global Surveyor TES Data
Geophys. Res. Lett. Vol. 27 , No. 23 , p. 3889 (2000GL012028)
keywords: 3346 Meteorology and atmospheric dynamics; Planetary meteorology (5445, 5739) 3384 Waves and tides 5409 Planetology: solid surface planets; Atmospheres--structure and dynamics
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Oguri, Kazumasa ; Matsumoto, Eiji ; Saito, Yoshiki ; Honda, Makio C. ; Harada, Naomi ; Kusakabe, Masashi 2000
Evidence for the offshore transport of terrestrial organic matter due to the rise of sea level: The case of the East China Sea continental shelf
Geophys. Res. Lett. Vol. 27 , No. 23 , p. 3893 (2000GL011690)
keywords: 4243 Oceanography: general; Marginal and semienclosed seas 4863 Oceanography: biological and chemical; Sedimentation 4870 Stable isotopes
Le Bec, Nolwenn ; Juillet-Leclerc, Anne ; Corrège, Thierry ; Blamart, Dominique ; Delcroix, Thierry 2000
A coral 
18O record of ENSO driven sea surface salinity variability in Fiji (south - western tropical Pacific)
Geophys. Res. Lett. Vol. 27 , No. 23 , p. 3897 (2000GL011843)
keywords: 4215 Oceanography: general;Climate and interannual variability (3309) 4522 Oceanography: physical; El Niño 4870 Oceanography: biological and chemical; Stable isotopes 9355 Information related to geographic region; Pacific Ocean
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Lough, J. M. 2000
1997-98: Unprecedented thermal stress to coral reefs?
Geophys. Res. Lett. Vol. 27 , No. 23 , p. 3901 (2000GL011715)
keywords: 1635 Global change (new category); Oceans (4203) 4215 Oceanography: general; Climate and interannual variability (3309) 4522 Oceanography: physical; El Niño 4815 Oceanography: biological and chemical; Ecosystems, structure and dynamics
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Figueroa, Dante ; Moffat, Carlos 2000
On the influence of topography in the induction of coastal upwelling along the Chilean coast
Geophys. Res. Lett. Vol. 27 , No. 23 , p. 3905 (1999GL011302)
keywords: 4259 Oceanography: general; Ocean acoustics 4520 Oceanography: physical; Eddies and mesoscale processes
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Min, Dong-Ha ; Bullister, John L. ; Weiss, Ray F. 2000
Constant ventilation age of thermocline water in the eastern subtropical North Pacific Ocean from chlorofluorocarbon measurements over a 12-year period
Geophys. Res. Lett. Vol. 27 , No. 23 , p. 3909 (1999GL011318)
keywords: 4223 Oceanography: general; Descriptive and regional oceanography 4522 Oceanography: physical; El Niño 4532 General circulation 4808 Oceanography: biological and chemical; Chemical tracers
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You, Yuzhu 2000
Contribution of salt-fingering to the conveyor belt circulation in the abyssal northern Indian Ocean
Geophys. Res. Lett. Vol. 27 , No. 23 , p. 3913 (1999GL002386)
keywords: 4279 Oceanography: general; Upwelling and convergences 4500 Oceanography: physical 4524 Fine structure and microstructure 4568 Turbulence, diffusion, and mixing processes
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Lehmann, Bernhard E. ; Lehmann, Martin ; Neftel, Albrecht ; Tarakanov, Sergei V. 2000
Radon-222 Monitoring of Soil Diffusivity
Geophys. Res. Lett. Vol. 27 , No. 23 , p. 3917 (1999GL008469)
keywords: 0932 Exploration geophysics; Radioactivity methods 1866 Hydrology; Soil moisture 1894 Instruments and techniques
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Soler, Tomás ; Foote, Richard H. ; Hoyle, Dixon ; Bocean, Virgil 2000
Accurate GPS orientation of a long baseline for neutrino oscillation experiments at Fermilab
Geophys. Res. Lett. Vol. 27 , No. 23 , p. 3921 (2000GL011539)
keywords: 1204 Geodesy and gravity; Control surveys 1243 Space geodetic surveys 1247 Terrestrial reference systems 1294 Instruments and techniques
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Larson, Kristine M. ; van Dam, Tonie 2000
Measuring Postglacial Rebound with GPS and Absolute Gravity
Geophys. Res. Lett. Vol. 27 , No. 23 , p. 3925 (2000GL011946)
keywords: 1200 Geodesy and gravity 1236 Rheology of the lithosphere and mantle (8160) 1243 Space geodetic surveys 1294 Instruments and techniques
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Bock, Günter ; Schurr, Bernd ; Asch, Günter 2000
High-resolution image of the oceanic Moho in the subducting Nazca plate from P-S converted waves
Geophys. Res. Lett. Vol. 27 , No. 23 , p. 3929 (2000GL011881)
keywords: 7200 Seismology 7203 Body wave propagation 7218 Lithosphere and upper mantle 7220 Oceanic crust
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Pezard, Philippe A. ; Einaudi, Florence ; Hermitte, Daniel ; Cochemé, Jean-Jacques ; Coulon, Christian ; Laverne, Christine 2000
MORB emplacement and structure: Insights from the Semail ophiolite, Oman
Geophys. Res. Lett. Vol. 27 , No. 23 , p. 3933 (2000GL011877)
keywords: 3035 Marine geology and geophysics; Midocean ridge processes 5109 Physical properties of rocks; Magnetic and electrical properties
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Elkins Tanton, Linda T. ; Hager, Bradford H. 2000
Melt intrusion as a trigger for lithospheric foundering and the eruption of the Siberian flood basalts
Geophys. Res. Lett. Vol. 27 , No. 23 , p. 3937 (2000GL011751)
keywords: 3210 Mathematical geophysics (new field); Modeling 8121 Tectonophysics; Dynamics, convection currents and mantle plumes 8159 Rheology--crust and lithosphere 8414 Volcanology; Eruption mechanisms
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Tatsumi, Yoshiyuki 2000
Slab melting:Its role in continental crust formation and mantle evolution
Geophys. Res. Lett. Vol. 27 , No. 23 , p. 3941 (2000GL012061)
keywords: 1010 Geochemistry (new field, replaces rock chemistry); Chemical evolution 1020 Composition of the crust 1025 Composition of the mantle
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Pulido, N. ; Irikura, K. 2000
Estimation of Dynamic Rupture parameters from the Radiated Seismic Energy and Apparent Stress
Geophys. Res. Lett. Vol. 27 , No. 23 , p. 3945 (2000GL011658)
keywords: 7209 Seismology; Earthquake dynamics and mechanics
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McNamara, D. E. 2000
Frequency Dependent Lg Attenuation in South-Central Alaska
Geophys. Res. Lett. Vol. 27 , No. 23 , p. 3949 (2000GL011732)
keywords: 7200 Seismology 7205 Continental crust (1242) 7212 Earthquake ground motions and engineering
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Thybo, H. ; Perchuç, E. ; Zhou, S. 2000
Intraplate earthquakes and a seismically defined lateral transition in the upper mantle
Geophys. Res. Lett. Vol. 27 , No. 23 , p. 3953 (2000GL011636)
keywords: 0905 Exploration geophysics; Continental structures (8109, 8110) 7200 Seismology 7209 Earthquake dynamics and mechanics 8120 Tectonophysics; Dynamics of lithosphere and mantle--general
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Papazachos, B. C. ; Karakaisis, G. F. ; Papazachos, C. B. ; Scordilis, E. M. 2000
Earthquake Triggering in the North and East Aegean Plate Boundaries due to the Anatolia Westward Motion
Geophys. Res. Lett. Vol. 27 , No. 23 , p. 3957 (2000GL011425)
keywords: 7209 Seismology; Earthquake dynamics and mechanics 7223 Seismic hazard assessment and prediction 7230 Seismicity and seismotectonics 9335 Information related to geographic region; Europe
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Dixon, Timothy ; Farina, Fred ; DeMets, Charles ; Suarez-Vidal, Francisco ; Fletcher, John ; Marquez-Azua, Bertha ; Miller, Meghan ; Sanchez, Osvaldo ; Umhoefer, Paul 2000
New Kinematic Models for Pacific-North America Motion from 3 Ma to Present: Evidence for a "Baja California shear zone"
Geophys. Res. Lett. Vol. 27 , No. 23 , p. 3961 (2000GL008529)
keywords: 1206 Geodesy and gravity; Crustal movements--interplate (8155) 1243 Space geodetic surveys 8107 Tectonophysics; Continental neotectonics
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Geophysical Research Letters, December 1, 2000
For more than a day, centered around universal-time (UT) midday on May 11, 1999, an unusually extended depression in the plasma density of the solar wind occurred in the vicinity of Earth. The density fell to 0.1-0.2 protons cm-3 compared with average solar wind densities of ~5 particles cm-3. The papers in this special section describe several aspects of this event.
One consequence of this unusual, extremely tenuous solar wind was a spectacular expansion of the Earth's bow shock, captured as it passed by several spacecraft (see for example plots of the solar wind parameters in Richardson et al. [3761] and Terasawa et al. [3781]). The shock reached record up-stream distances, extending out to at least Lunar orbit (~ 60 RE). While the solar source of this temporary decrease in the number of parti-cles escaping the Sun remains elusive, Usmanov et al. [3765] discuss a possible association with an interval of strong rearrangement of the global magnetic field inferred from photospheric observations. Another possible clue to the origin is the eleven year cycle in the occurrence rate of similar intervals of unusually low density solar wind as noted by Crooker et al. [3769] and Richardson et al. from reviewing extended solar wind observations. Such intervals are rare during solar minimum but become more frequent during the approach to and near solar maximum. Richardson et al. further suggest that low density regions may be more prominent during weaker solar cycles (e.g., cycle 20 and the current cycle).
Consequences of this tenuous solar wind included a steady intense polar rain onto the northern cusp region and a dipolarization of the geomagnetic field, extending as far as six Earth radii (Farrugia et al. [3773]). There were also subtle but global rearrangements of the magnetospheric currents, with observable effects manifested at very high magnetic latitude (Rostoker [3789], Ohtani et al. [3777], and Papitashvili et al. [3785]).
Avila and Pereyra [3837] conduct laboratory experi-ments concerned with ice crystal-graupel interactions. They analyze the influence of the cloud-droplet spectrum on charge separation during ice crystal-graupel collisions for two different cloud droplet spectra for a range of tem-perature and effective liquid water content. Size distribution of the cloud droplets is found to be crucial to the sign of the electric charge transferred in the collisions. Moreover, negative charging of graupel has a high possibility of occurrence in cloud regions having broad droplet spectra. Both small droplets and large values of cloud water content are observed to encourage positive charg-ing.
Analyzing 1985-1997 observations of ozone concentra-tions in the marine boundary layer at Cape Grim (Tasmania), Galbally et al. [3841] detect a decrease in ozone concentration following visible sunrise (centered at 0800 to 0900 hours) in both December-January and June-July. The sunrise ozone decrease produces an asymmetry in the daily ozone loss rate. Occurring at similar rates in mid-summer and mid-winter, this decrease is statistically different from that caused by the ozone - HOx (odd hydrogen radicals) destruction cycle peaking at midday and unable to account for the sunrise ozone decrease. The authors speculate that halogen chemistry results in the sunrise ozone destruction, and rule out physical processes such as mixing or transport.
Leewave activity characterized the meteorological situa-tion above Scandinavia on 25 Jan 1998 when mountain-induced gravity waves led to the formation of mesoscale polar stratospheric clouds (PSCs). Voigt et al. [3873] perform balloon-borne mass spectrometric measurements of particle composition and optical backscatter measure-ments above Sweden. After reaching a cold layer at 20 km altitude, PSCs are encountered twice, identified by a correlated increase in the backscatter ratio and in the mass spectrometer signals for condensed water and nitric acid. Between the two PSC encounters, the authors observe an uptake of water into the particles with decreasing temperatures, with the nitric acid signal remaining below the detection limit. They identify the PSC particles as super-cooled ternary solution droplets.
Le Bec et al. [3897] examine nearly 40 years (1960-1998) of oxygen isotopic composition (18O) data from a coral in Fiji, and find a strong positive correlation between sea surface salinity (SSS) in the region and 18O. Since El Niño events are characterized by high SSS in Fiji (and La Niña events by low SSS), the authors argue that in the Fiji area,18O records of massive corals can be used to track El Niño - Southern Oscillation events back in time.
Examining chlorofluorocarbon (CFC) data for 1982-1994 that was collected near the Geochemical Ocean Sections Study station 1 in the northeastern Pacific, Min et al. [3909] find a record of decadal timescale ventilation pro-cesses of the subtropical thermocline in the region. Dur-ing El Niño, ventilation of the thermocline by subarctic waters is substantially limited and vertical inventories of CFCs are reduced. The authors construct a simple one-dimensional advection-diffusion model to simulate the region's observed temporal CFC-11 and CFC-12 changes. The model shows that the changes are primarily governed by advection, with only a minor contribution from iso-pycnic diffusion.
Elkins-Tanton and Hager [3937] propose a novel mechanism for triggering massive flood basalt eruptions. These eruptions occur according to which continents ride over existing modest upwellings and when the upwellings reach lithosphere that is thin enough adiabatic melting results. The authors suggest that the melt intrudes into and heats the mantle lithosphere, lowering its viscosity and increasing its density. Raleigh-Taylor instability then removes the warm, dense mantle lithosphere, causing surface subsidence.
Two arrows indicate the direction of the dramatic expansion of the Earth's bowshock, between May 10 and 11, 1999. The lines give four instant locations of the bowshock, and their colors, from red to light green-yellow, indicate the gradual weakening of the bow shock strength as a function of the reduction of the solar wind presence. Overimposed on a map of the Earth, in the upper left corner, a PIXIE/POLAR X-ray image of the magnetic north polar region shows an unusual, nearly uniform, electron precipitation ("polar rain") on May 11, 1999. In the bottom-right corner, an image of the Moon behind the solid green-yellow line illustrates the extreme displacement of the bowshock, away from the Earth. The Earth's bowshock passed 1st. Geotail (at 1645UT, 5/10, at ~27 Re from Earth), 2nd. Interball-1 and its companion Magion-4 sub-satellite, (at 0047UT, ~24 Re), 3rd. IMP-8, (at 1115UT, ~33 Re), 4th. Wind (at 1730UT, ~52 Re), and 5th (and final) the Lunar Prospector, which was orbiting the Moon (at 1733UT, ~58 Re).
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