‫ ౎ ژ‬େ ֶ ๷ ࡂ ‫ ॴ ڀ ݚ‬೥ ใɹୈ48߸B ฏ੒17೥4݄

Annuals of Disas. Prev. Res. Inst., Kyoto Univ., No. 48 B, 2005ྖҬେ‫ؾ‬ϞσϧΛ༻͍ͨ೤ଳରྲྀ‫ݍ‬த૚ͷ૚ঢ়ߏ଄ʹؔ͢Δ਺஋࣮‫ݧ‬େ௩੒ಙɾ༨ా੒உ‫౎ژ‬େֶେֶӃཧֶ‫ڀݚ‬Պཁɹࢫ೤ଳରྲྀ‫ݍ‬த૚Ͱ͠͹͠͹‫؍‬ଌ͞ΕΔਫৠ‫ؾ‬ͷ૚ঢ়ߏ଄ʹ͍ͭͯɼͦͷࡾ࣍‫ݩ‬తߏ଄΍෺࣭༌ૹతಛ௃Λௐ΂ΔͨΊʹϝιεέʔϧͷྖҬେ‫ؾ‬ϞσϧΛ༻͍ͯ਺஋࣮‫ݧ‬Λߦͬͨɻ࠶‫Ͱݧ࣮ݱ‬ಘΒΕͨߴ࣪౓ͷ૚ঢ়ߏ଄ͷਫฏεέʔϧ͸໿ 1000kmɼԖ௚εέʔϧ͸
໿ 1km Ͱ͋ͬͨɻ૚ঢ়ߏ଄͕ग़‫ྖͨ͠ݱ‬ҬΛத৺ʹେྔཻࢠ‫܈‬ͷ‫ํޙ‬௥੻࣮‫ݧ‬Λߦͬͨͱ
͜Ζɼ૚ঢ়ߏ଄ͷ࣪५ͳ෦෼͸๺੢෩ʹΑΓ೤ଳऩଋଳ͔ΒҠྲྀ͞Ε͖͓ͯͯΓɼͦͷ্Լͷ‫ס‬૩ͨ͠෦෼͸ೆ౦͔ΒҠྲྀ͞Ε͖͍ͯͯͨɻྲྀઢղੳͷ݁Ռɼ૚ঢ়ߏ଄ͷ੒Ҽ͸ɼ౦੢ʹฒΜͩೋͭͷ૯‫ن؍‬໛Ӕͷؒʹ͋ΔΑͲΈ఺ͷҐஔ͕Ԗ௚ʹͣΕ͍ͯΔ͜ͱͰ͋Δ͜ͱ͕Θ͔ͬͨɻΩʔϫʔυ: ೤ଳऩଋଳɼରྲྀ‫ݍ‬த૚ɼ૚ঢ়ߏ଄ ͸͡Ίʹ

(Newell et al., 1996) ΍ PEM-Tropics A (Stoller et al.,1999) ͷଠฏ༸த෦ɾ੢෦Ͱͷඈߦ‫ػ‬Ωϟϯϖʔϯ‫؍‬1999 ೥ʹ౦෦ଠฏ༸੺ಓҬʹ͓͍ͯௐࠪધʮর༸ଌͳͲʹΑΓల։͞Εͨɻ͜ΕΒͷ‫Ͱڀݚ‬͸ඍྔ੒‫ؙ‬ʯʹΑΔΦκϯκϯσ‫؍‬ଌ͕ Soundings of Ozone෼ͷ૊੒ൺΛ΋ͱʹۭ‫ؾ‬մͷ‫͕ݯى‬ਪఆ͞Ε͍ͯΔɻ

and Water in the Equatorial Region (SOWER)/Paciﬁc ‫ܭ‬Ұํɼରྲྀ‫ݍ‬த૚ͷ 0◦ C ҆ఆ૚ͱͦΕʹ൐͏Ӣͷ૚ըͷҰ‫ߦͯ͠ͱ؀‬ΘΕͨ (Shiotani et al., 2002)ɻর༸

ঢ়ߏ଄ʹ͍ͭͯ͸ Johnson et al. (1999) ͳͲͷ‫͕ڀݚ‬‫ؙ‬͸๺Ң 2 ౓ઢʹԊͬͯ੢‫ ܦ‬140 ౓ (9 ݄ 21 ೔) ͔Β͋Δɻߴ౓ 5km ෇ۙͷ 0◦ C ҆ఆ૚͕Ӣͷ੒௕Λ཈੍

110 ౓ (9 ݄ 28 ೔) ·Ͱ౦ਐ͠ɼͦͷ‫ޙ‬๺Ң 10 ౓ɼ੢͠ɼ༤େੵӢΛੜͤ͡͞ɼ༤େੵӢ͔ΒͷστϨΠ‫ ܦ‬95 ౓ (10 ݄ 7 ೔) ·Ͱ๺౦ʹਐΜͩɻԘ୩Β͸ͦϝϯτʹΑΓରྲྀ‫ݍ‬த૚ʹ࣪५ͳۭ‫͞څڙ͕ؾ‬ΕΔͷ‫ؒظ‬தΦκϯκϯσ‫؍‬ଌΛߦ͍ɼ૬ର࣪౓ͱΦκͱߟ͑ΒΕ͍ͯΔɻϯͷ૚ঢ়ߏ଄Λߴ౓ 2kmɼ5kmɼ9km ෇ۙʹ͠͹͠ϥδΦκϯσ‫؍‬ଌ΍ඈߦ‫؍ػ‬ଌ͸࣌ؒతۭؒతʹ͹‫؍‬ଌͨ͠ɻԖ௚εέʔϧ͸໿ 1ʙ2km Ͱ͋ͬͨɻ͜‫ݶ‬ΒΕΔ͕ɼ΋͠਺஋࣮‫ʹݧ‬ΑΓ࢛࣍‫ݩ‬σʔλ͕ಘΕΒͷ૚Ͱ͸૬ର࣪౓͕Φκϯ΍ೆ๺෩ͱ‫ٯ‬૬ؔʹΒΕΕ͹ɼ૚ঢ়ߏ଄ͷ࣌ؒมಈɼྗֶతಛ௃ɼ෺࣭

ͳ͍ͬͯͨɻͭ·Γ࣪५ͳ૚͸Φκϯͷೱ౓͕௿͘ɺ༌ૹతಛ௃ͳͲʹ͍ͭͯ஌Δ͜ͱ͕Ͱ͖Δɻͦ͜Ͱɼ๺෩͕ਧ͍͍ͯͨɻԘ୩Β͸ɼւ໘෇ۙͷۭ‫ؾ‬͸Φຊ‫Ͱڀݚ‬͸ϝιεέʔϧͷྖҬେ‫ؾ‬ϞσϧΛ༻͍ͯɼκϯʹ๡͍͜͠ͱ͔Βɼ೤ଳऩଋଳʹ͓͍ͯରྲྀ‫ݍ‬র༸‫؍ؙ‬ଌ‫ؒظ‬ͷ͏ͪͷ 3.5 ೔ؒʹ͍ͭͯ਺஋࣮‫ݧ‬Λத૚ʹ্࣋ͪ͛ΒΕͨ࣪५ͰΦκϯʹ๡͍ۭ͠‫ؾ‬մߦ͏ɻ͕๺෩ͰҠྲྀ͞Ε͖ͯͨͱਪଌͨ͠ɻ૚ঢ়ߏ଄ʹؔ͢Δઌߦ‫ͯ͠ͱڀݚ‬͸ɼDanielsen etal. (1987) ʹΑΔେ‫ؾ‬ඍྔ੒෼ͷ૚ঢ়ߏ଄ͷ‫؍‬ଌใࠂ͕͋Δɻͦͷ‫ޙ‬ɼ૚ঢ়ߏ଄ͷ‫ڀݚ‬͸ PEM-West A

Fig. 1 Outgoing longwave radiation at 48 h from the initial time of integration. The inner white box shows the area ofDomain 2. The white line beginning from lower left side of the ﬁgure shows the cruise track of Shoyo-Maru.

 Ϟσϧຊ‫ͨ͠༻࢖Ͱڀݚ‬Ϟσϧ͸ɼඇ੩ྗֶྖҬେ‫ؾ‬Ϟσϧͷ The Fifth-Generation NCAR/Penn State Mesoscale

Model (MM5) Ͱ͋Δɻ‫ྖࢉܭ‬Ҭ͸ Fig. 1 ʹࣔͨ͠Α͏ʹ౦෦ଠฏ༸ͷ੢‫ ܦ‬62 ౓ʙ128 ౓ɼೆҢ 1 ౓ʙ๺Ң 20 ౓Ͱ͋ΔɻϞσϧ͸ೋͭͷυϝΠϯ͔Β੒Γɼ2-way nesting ͍ͯ͠Δɻ֎ଆͷ Domain 1 ͸ 40×120 άϦουͰɼ֨ࢠִؒ͸ 63 km Ͱ͋Δɻ಺ଆͷ Domain2 ͸ 73×211 άϦουͰɼ֨ࢠִؒ͸ 21 km Ͱ͋ΔɻԖ௚ʹ͸஍ද͔ΒԼ෦੒૚‫ݍ‬ͷ 25 hPa ·Ͱ 62 ૚͋ΔɻԖ௚֨ࢠִؒ͸ରྲྀ‫ݍ‬த૚Ͱ͸໿ 300 m Ͱ͋ΔɻೋͭͷυϝΠϯͱ΋ੵӢύϥϝλϦθʔγϣϯΛ༻͍͓ͯΓɼඍ෺ཧύϥϝλϦθʔγϣϯ͸ӢਫɾӍਫɾණɾઇΛ‫ؚ‬Ή΋ͷΛ༻͍ͨɻ์ࣹաఔ͸௕೾ɾ୹೾Λ‫ؚ‬ΈɼಛʹӢ͔Βͷ௕೾์ࣹ΋ѻ͍ͬͯΔɻ‫ؒظࢉܭ‬͸ 1999 ೥ 9 ݄ 26 ೔ 00 UTCʙ9 ݄ 29 ೔ 12 UTC ͷ

3.5 ೔ؒͰ͋Δɻॳ‫ظ‬஋ɾ‫ڥ‬ք஋ʹ༩͑Δσʔλͱͯ͠͸ਫฏղ૾౓ 1 ౓ɼִ࣌ؒؒ 6 ࣌ؒͷ NCEP GlobalFig. 2 Vertical proﬁles of relative humidity (RH, solid

Tropospheric Analyses (FNL) Λ༻͍ͨɻline with open circles) and meridional wind compo-Ϟσϧͷ࠶‫ݱ‬ੑΛࣔͨ͢Ίʹ͍͔ͭ͘ͷ݁ՌΛࣔnent (V, dotted line with asterisks, positive value means͢ɻFig. 1 ͸‫ࢉܭ‬։͔࢝Β 48 ࣌ؒ‫( ޙ‬9 ݄ 28 ೔ 00southerly) at 109.7◦ W and 4.9◦ N, t = 48 h. Gray andUTC) ͷ্޲͖௕೾์ࣹ (OLR) ͷਤͰ͋ΔɻOLR ͷ

vertical dashed lines show thresholds to extract the lay-෼෍͸Ӵ੕੺֎ը૾ͷύλʔϯͱΑ͘ࣅ͍ͯΔɻ೤

ered structure. Gray and horizontal dashed lines showଳऩଋଳͷӢྻ͕๺Ң 10 ౓෇ۙʹԊͬͯ੢‫ ܦ‬120 ౓

the range of analysis. Thick line part of the RH proﬁle͔Β 80 ౓෇ۙ·Ͱ৳ͼ͍ͯΔɻ

is an example of the layered structure.

૬ର࣪౓ͷԖ௚෼෍΋র༸‫؍ؙ‬ଌͷ݁ՌͱΑ͘ࣅͨ෼෍Λࣔ͢ɻFig. 2 ͸‫Ͱࢉܭ‬ಘΒΕͨରྲྀ‫ݍ‬த૚ͷ࣪५ͳ૚ঢ়ߏ଄ͷྫͰ͋Δɻೆ๺෩ (ഁઢ) ͕ߴ౓ 2
ʙ6 km Ͱ૬ର࣪౓ (࣮ઢ) ͱ‫ٯ‬૬ؔΛ͍ࣔͯ͠Δͷ͕ ݁Ռ ૚ঢ়ߏ଄ͷ෼෍·ͣ૬ର࣪౓ͷԖ௚ϓϩϑΝΠϧΛ༻͍ͯ૚ঢ়ߏ଄ͷఆٛΛߦ͏ɻ͜͜Ͱ͸࠷΋࣪५ͳ෦෼͕૬ର࣪౓

65%Ҏ্ɼ࣪५ͳ෦෼ͷ্ԼͰ࠷΋‫ס‬૩ͨ͠෦෼͕૬ର࣪౓ 30%ҎԼͷ΋ͷΛ૚ঢ়ߏ଄ͱͨ͠ɻDomain 2ͷ‫݁ࢉܭ‬Ռͷ͏ͪରྲྀ‫ݍ‬த૚ʹ஫໨͢ΔͨΊʹղੳ͸ 700ʙ400 hPa ͷൣғʹ‫ͨͬߦͯͬݶ‬ɻ·ͨɼ͜ͷൣғͰಛʹബ͍૚ʹ஫໨͢ΔͨΊʹ૬ର࣪౓ 30%Ҏ্ͷ෦෼ͷް͕͞ 150 hPa (∼ 2 km) ҎԼͷ΋ͷΛந

Fig. 3 Zonal section of relative humidity (RH) at 4.9◦ N,t = 48 h (00 UTC 28 Sep. 1999).
Θ͔Δɻͭ·Γ࣪५ͳ෦෼Ͱ͸๺෩͕ਧ͖ɼ‫ס‬૩ͨ͠෦෼Ͱ͸ೆ෩ʹͳ͍ͬͯΔɻߴ౓ 5ʙ6 km ෇ۙʹ͋Δ࣪५૚ͷԖ௚εέʔϧ͸໿ 1.5 km Ͱɼর༸‫؍ؙ‬ଌͰಘΒΕͨ΋ͷͱಉఔ౓Ͱ͋ΔɻFig. 3 ͸‫݁ࢉܭ‬Ռʹ͓͚Δ૬ର࣪౓ͷ౦੢Ԗ௚அ໘ਤͰ͋Δɻશൠʹରྲྀ‫্ݍ‬෦͸૬ର࣪౓͕ߴ͘ɼ౦ͷํ΄Ͳ࣪५ͳ෦෼ͷԼ୺͕௿͍ɻ·ͨɼFig. 2 ʹ‫ݟ‬ΒΕͨ 500 hPa෇ۙͷ࣪५૚͕੢‫ ܦ‬108 ౓ʙ122 ౓ʹ޿͕͍ͬͯΔɻ͜ͷ݁Ռ͸ Shiotani et al. (2002) ͷ Fig. 7 ΍ Fujiwara

et al. (2003) ͷ Fig. 3a Ͱࣔ͞Ε͍ͯΔΑ͏ͳর༸‫ؙ‬‫؍‬ଌʹ͓͚Δ૬ର࣪౓ͷ‫౓ܦ‬෼෍ͱࣅͨಛ௃Λ͍ࣔͯ͠Δɻզʑͷ‫݁ࢉܭ‬Ռ͸૚ঢ়ߏ଄ͷ༷ʑͳಛ௃ΛΑ͘࠶‫͓ͯ͠ݱ‬ΓɺMM5 ʹ͓͚ΔੵӢ΍ඍ෺ཧͷύϥϝλ

ग़ͨ͠ɻFig. 2 ͸͜ΕΒͷ৚݅ͰಘΒΕͨ૚ঢ়ߏ଄ͷయ‫͋Ͱྫܕ‬ΔɻͦͷԖ௚ͷ޿͕Γ͸໿ 1.5 km Ͱ͋ΔɻFig. 4 ͸૚ঢ়ߏ଄͕‫ݟ‬ΒΕͨྖҬͷਫฏ෼෍ਤͰ͋
Δɻഎ‫ܠ‬ͷτʔϯ͸‫ݻ‬ମɾӷମͷਫͷԖ௚ੵࢉྔΛ
͍ࣔͯ͠Δɻ๺Ң 8 ౓ʙ12 ౓ʹ͸೤ଳऩଋଳͷରྲྀӢͷ͔ͨ·Γ͕‫͑ݟ‬Δɻ૚ঢ়ߏ଄͸೤ଳऩଋଳͷೆଆͷରྲྀ‫׆‬ಈͷগͳ͍Ժ΍͔ͳྖҬʹग़‫͍ͯ͠ݱ‬ΔɻҰํ೤ଳऩଋଳͷ๺ଆʹ͸૚ঢ়ߏ଄͸‫ݟ‬ΒΕͳ͍ɻ૚ঢ়ߏ଄ͷग़‫ྖݱ‬Ҭͷ౦੢εέʔϧ͸໿ 1000 kmɼೆ๺εέʔϧ͸໿ 400 km Ͱ͋Δɻ࠷΋େ͖͍૚ঢ়ߏ଄
ͷ͔ͨ·Γ͸ t = 20 h ͘Β͍ʹग़‫࢝͠ݱ‬Ίɼt = 48h ʹ໘ੵ͕࠷େʹͳͬͨ‫ޙ‬ɼ౦੢ʹҾ͖৳͹͞Εͳ͕Βॖখ͍ͯͬͨ͠ɻ͜ͷ͔ͨ·Γͷण໋͸ 1ʙ2 ೔͘Β͍Ͱ͋Δɻ૚ঢ়ߏ଄ͷԼ୺ (૬ର࣪౓͕ 30%ʹͳΔͱ͜Ζ) ͷߴ౓͸໿ 4.5 km Ͱɼ૚ঢ়ߏ଄ͷ͔ͨ·ΓͷதͰ͸΄΅Ұ༷Ͱ͋Δ͕ɼ૚ঢ়ߏ଄ͷް͞͸੢ͷํ΄Ͳް͘ (∼1.5 km)ɼ౦ͷํ΄Ͳബ͍ (<1 km)ɻϦθʔγϣϯͷબͼํʹ͍ͭͯ΋ద੾ͱ൑அͰ͖Δɻͦ͜ͰҎԼͰ͸͜ͷରྲྀ‫ݍ‬த૚ͷ૚ঢ়ߏ଄ʹ͍ͭͯ͞ΒʹղੳΛਐΊΔɻ

Fig. 4 Horizontal distribution of the area where the layered structures are obtained at t = 24 h, 36 h, 48 h, and 60 h inwhite. Column amount of cloud water content (CWC) in also shown with gray tones.

Fig. 5 Backward trajectory analysis. Top: Projectionof the trajectories onto a meridional plane. The “initial”
positions are located at around 400 km from the southern

Fig. 6 Three-dimensional transport visualized by de-end of the plot and around 4.4 km, 5.1 km, 5.8 km, andformation of a lattice, which consists of a large amount

6.6 km in height. Bottom: Projection of the trajectoriesof tracer particles. The particles that moved southward

onto a horizontal plane. The “initial” positions are atare shown in black, and those moved northward aregrid number (x, y) = (80, 21), which is about 106◦ W,

shown in gray. Black lines and gray lines on the merid-◦

6.5 N. The gray tones are as same as those in the top

ional plane are the projection of the particles that movedpanel.

southward and northward, respectively.

 େྔཻࢠ௥੻࣮‫ݧ‬ࢠ‫)܈‬ɻ͜ΕΒͷ݁Ռ͸࣪५૚͕๺෩ͷ෦෼ͱରԠ͠େ‫ؾ‬தͷτϨʔαʔ෺࣭͕૚ঢ়ߏ଄ͷपΓͰͲͷ͍ͯΔͱ͍͏‫؍‬ଌ݁Ռͱ΋Ұக͠ɼߴ࣪౓ͷۭ‫͕ؾ‬Α͏ʹ༌ૹ͞Ε͍ͯΔͷ͔Λௐ΂ΔͨΊʹɼ‫͞ࢉܭ‬೤ଳऩଋଳ͔ΒਫฏʹҠྲྀ͞Ε͖ͯͨͱ͍͏ ShiotaniΕͨ෩ͰԾ૝ཻࢠΛྲྀཻ͢ࢠ௥੻࣮‫ݧ‬ΛߦͬͨɻҰͭ

et al. (2002) ͷਪଌΛཪ෇͚Δ΋ͷͰ͋ΔɻΊͷ࣮‫ͯ͠ͱݧ‬ɼt = 48 h ʹ૚ঢ়ߏ଄ͷԼ (4.4 km)ɼ࣍ʹ΋͏ͻͱͭ࣌ؒΛ૎ཻͬͯࢠ‫܈‬ͷ‫ݯى‬Λௐ΂Δதԝ (5.1 km)ɼ্ (5.8 km ͱ 6.6 km) ͷ‫ݶ‬ΒΕͨྖҬ‫܈ࢠཻํޙ‬௥੻࣮‫ݧ‬Λߦͬͨ (ਤ͸লུ)ɻt = 48 h ʹʹ 6250 ‫ࢠཻͭͣݸ‬Λ഑ஔ͠ɼ࣌ؒΛ૎ͬͯ t = 12 h͓͍ͯ૚ঢ়ߏ଄͕‫ݟ‬ΒΕͨશྖҬͰɼ࣪५෦෼ (550·Ͱ௥੻͢Δ‫੻ྲྀํޙ‬ઢղੳΛߦͬͨɻ࣪५૚ͷ಺෦hPa) ʹਫฏʹཻࢠΛ഑ஔ͠ɼt = 12 h ·Ͱ‫ํޙ‬௥੻ʹཻ͓͍ͨࢠ͸๺੢͔Βདྷ͍ͯͨ (Fig. 5 Լਤͷࠨ্ͨ͠ɻۭ‫ؾ‬մͷಈ͖͸ɼFig. 4 ʹࣔͨ͠૚ঢ়ߏ଄ͷಈͷཻࢠ‫)܈‬ɻͦͷཻࢠͷଟ͘͸ւ༸্େ‫ڥؾ‬ք૚͔Β͖ͱ͸ҟͳΓɼ͕࣌ؒਐΉʹͭΕͯɼཻࢠ͕ଘࡏ͢ରྲྀʹΑ্ͬͯ࣋ͪ͛ΒΕͯରྲྀ‫ݍ‬த૚ʹདྷ͍ͯͨΔྖҬ͸ೆ੢͔Β๺౦ͷํ޲ʹҾ͖৳͹͞Εɼ๺੢(Fig. 5 ্ਤͷӈͷཻࢠ‫)܈‬ɻҰํɼ࣪५૚ͷ্Լʹ͔͋Βೆ౦ͷํ֯ʹ͸ѹॖ͞Ε͍ͯͨɻ͜Ε͸࣍ͷ 3.3Δ‫ס‬૩ͨ͠૚ʹஔཻ͍ͨࢠ͸ɼೆ౦͔Β΄΅ਫฏʹઅͰ‫ݟ‬ΔΑ͏ʹɼਫฏྲྀ଎৔͕ΑͲΈ఺ (Ҍ఺) Λ࣋དྷ͍ͯͨ (Fig. 5 ্ਤͷࠨͷཻࢠ‫܈‬ɼԼਤͷӈԼͷཻͭ͜ͱʹ‫ى‬Ҽ͢Δɻ

Fig. 7 Horizontal sections of relative humidity (gray scale) and streamlines at 0.45 (top panel, about 460 hPa), 0.51(middle panel, about 520 hPa), and σ = 0.57 (bottom panel, about 580 hPa), at t = 48 h. Cross marks indicate saddle
points of ﬂow at each level. Areas which are surrounded by gray lines indicate regions of the layered structures.
࠷‫ʹޙ‬૚ঢ়ߏ଄‫ܗ‬੒ͷۭؒґଘੑΛௐ΂ΔͨΊʹɼೆ޲͖ʹ෩͕ਧ͍͍ͯΔɻ͜ͷྲྀΕ͸‫ج‬ຊతʹϋυt = 24 h ͔Β t = 48 h ·Ͱͷલํཻࢠ‫܈‬௥੻࣮‫ݧ‬Λߦͬͨɻॳ‫( ࠁ࣌ظ‬t = 24 h) ʹཻࢠΛ౦੢Ԗ௚அ໘ʹฏߦͳ໘্ʹ֨ࢠঢ়ʹ഑ஔͨ͠ (Fig. 6 ͷ্ஈ)ɻҐஔ͸๺Ң 5.9 ౓ɼ੢‫ ܦ‬115.8 ౓ʙ99.9 ౓ɼߴ౓ 4ʙ7km Ͱ͋ΔɻFig. 6 ͷதஈ͸ 12 ࣌ؒ‫ޙ‬ɼԼஈ͸ 24 ࣌Ϩʔ॥‫؀‬ͷҰ෦Ͱ͋Δɻ͔͠͠ରྲྀ‫ݍ‬த૚Ͱ͸ෳࡶͳೆ๺ྲྀ෼෍ʹͳ͍ͬͯΔɻ૚ঢ়ߏ଄ʹ൐͏෩ͷΦΠϥʔతӡಈΛௐ΂ΔͨΊʹɼྲྀઢղੳΛߦͬͨɻ֨ࢠͷதԝ෦෼ͷߴ౓ 5.5 km ෇ۙͷཻࢠ͸ೆʹมҐ

t = 48 h ʹ͓͚Δ σ = 0.45ɼ0.51ɼ0.57 Ͱͷྲྀઢ
Λ Fig. 7 ͷനઢͰࣔ͢ɻ͜͜Ͱ σ ͸஍ද໘‫ؾ‬ѹͰ‫ن‬֨Խͨ͠‫ؾ‬ѹͰ͋Δɻ֤Ϩϕϧʹ͓͍ͯɼ੢‫ ܦ‬120
౓ɼ๺Ң 8 ౓෇ۙʹ࣌‫ܭ‬ճΓͷӔ͕͋Γɼ͞Βʹ΋͏Ұͭ੢‫ ܦ‬90 ౓ɼ๺Ң 5 ౓෇ۙʹ΋࣌‫ܭ‬ճΓͷӔ͕͋Δɻ͜ͷೋͭͷӔͷதؒʹ͸ × ҹͰࣔͨ͠ҐஔʹΑͲΈ఺ɼΑΓਖ਼֬ʹ͸Ҍ఺͕͋Δɻ͜͜Ͱ σ = 0.51ϨϕϧͰ͸Ҍ఺͸૚ঢ়ߏ଄ (Fig. 7 ʹ͓͍ͯփ৭ͷઢͰғ·ΕͨྖҬ) ͷ౦ͷ୺ʹ͋ΔɻҰํɼଞͷೋͭͷͨ͠ɻೆ΁ͷมҐ͕‫ݟ‬ΒΕΔߴ౓͸੢΄Ͳߴ͔ͬͨɻϨϕϧͰ͸Ҍ఺͸૚ঢ়ߏ଄ͷҐஔΑΓ΋੢ͷํʹ͋ؒ‫ޙ‬ͷཻࢠ‫܈‬ͷҐஔΛද͢ɻࠇ৭ͱփ৭ͷཻࢠ͸ͦΕͧΕɼ‫ݩ‬ͷҐஔʹରͯ͠ೆʹಈ͍ͨ΋ͷͱ๺ʹಈ͍ͨ΋ͷΛද͢ɻ֨ࢠશମͱͯ͠͸౦੢ํ޲ʹҾ͖৳͹͞Ε͍ͯΔɻҰํɼೆ๺ํ޲ͷมҐʹ͍ͭͯ͸΍΍ෳࡶͰ͋Δɻେ൒ͷཻࢠ͸๺޲͖ʹมҐ͠ɼಛʹมҐ͕େ͖͔ͬͨͷ͸֨ࢠͷ౦ଆ্෦Ͱ͋ΔɻҰํɼ͜ͷ‫౓ܦ‬ґଘੑʹΑΓ૚ঢ়ߏ଄͸؇΍͔ʹ܏͍͓ͯΔɻσ = 0.51 ͰͷҌ఺ͱ σ = 0.45 ͰͷҌ఺ʹ‫·ڬ‬Γɼ౦΄Ͳߴ౓͕௿͘ͳ͍ͬͯΔɻ͜ͷ͜ͱ͸૚ঢ়ߏΕͨྖҬͰ͸ɼೆ๺෩੒෼͸૚ঢ়ߏ଄ͷ‫ܗ‬੒ʹ‫د‬༩଄͕੢Ͱް͘౦Ͱബ͍͜ͱͱ΋ؔ࿈͍ͯ͠Δɻ͢Δ෼෍ʹͳ͍ͬͯΔɻͭ·Γ σ = 0.51 Ͱ͸๺෩͕ਧ͖ɼͦͷ্Ͱ͸ೆ෩͕ਧ͍͍ͯΔɻ๺෩͸೤ଳऩ ྲྀઢղੳFig. 2 Λ‫ͯݟ‬Θ͔ΔΑ͏ʹɼ೤ଳऩଋଳͷೆଆʹଋଳ͔Β࣪५ͳۭ‫ؾ‬Λӡͼɼೆ෩͸૬ରతʹ‫ס‬૩͓͍ͯ͠ରྲྀ‫ݍ‬Լ૚Ͱ͸೤ଳऩଋଳʹ޲͔ͬͯ๺޲͖૚ঢ়ߏ଄͕‫ܗ‬੒͞Ε͍ͯΔɻʹ෩͕ਧ͖ɼҰํɼରྲྀ‫্ݍ‬૚Ͱ͸೤ଳऩଋଳ͔Βۭͨ‫ؾ‬ΛӡͿ͜ͱʹΑΓɼ͜ͷ‫౓ܦ‬ଳʹ૬ର࣪౓ͷσ = 0.57 ʹ͓͚ΔҌ఺ͷҐஔ͸ σ = 0.51 ΍ σ =Fig. 8 A time series of the horizontal section of relative humidity and streamlines at σ = 0.51 from t = 12 h tot = 48 h with a time step of ∆t = 12 h.
0.45 ʹ͓͚ΔҌ఺ͷҐஔΑΓ΋ͣͬͱ੢ʹͣΕ͍ͯ
ΔɻԖ௚ʹ‫ݟ‬Δͱ σ = 0.45 ʹ͓͚ΔҌ఺͕ߴ౓͕Լ͕ΔʹͭΕͯ࿈ଓతʹ౦ʹͣΕ͓ͯΓɼσ = 0.55 ෇Αࠞ͘߹͞Ε͍ͯΔɻ͔͠͠૚ঢ়ߏ଄͸ରྲྀʹΑͬۙͰෆ࿈ଓʹͳ͍ͬͯΔɻ͜ͷҌ఺ͷҐஔ͕౦੢ʹ͸ɼରྲྀʹΑͬͯཚ͞Εͳ͍‫ݶ‬ΓɼԺ΍͔Ͱ੒૚ͨ͠

ͣΕ͍ͯΔߏ଄͕ Fig. 6 Ͱ‫ͨݟ‬Α͏ͳ૚ঢ়ߏ଄ͷ؇େ‫ؾ‬ͷঢ়ଶ͕ۭؒతʹ͸૯‫ن؍‬໛ͷ޿͕ΓͰɼ࣌ؒ΍͔ͳ܏ࣼΛ‫ܗ‬੒͍ͯ͠ΔɻFig. 6 Ͱࠇ৭ͱփ৭ͷྖతʹ͸਺೔ͷ௕͞Ͱଘࡏ͢ΔՄೳੑΛ͍ࣔͯ͠ΔɻҬͷ্ଆͷ‫ڥ‬ք͸΄΅Ҍ఺ͷҐஔʹҰக͍ͯ͠Δɻେྔཻࢠͷ‫੻ྲྀํޙ‬ઢղੳʹΑΓɼ࣪५ͳ૚ͷۭ‫ؾ‬೤ଳͰ͸ରྲྀ‫׆‬ಈʹΑͬͯରྲྀ‫ݍ‬ͷ্͔ΒԼ·Ͱͯཚ͞ΕΔ͜ͱͳ͘ 1ʙ2 ೔࣋ଓ͍ͯͨ͠ɻ͜ͷ͜ͱ

Fig. 8 ͸ σ = 0.51 ʹ͓͚Δྲྀઢͷ࣌ؒมԽΛ૬ର͸૚ঢ়ߏ଄ͷ๺ଆͷ೤ଳऩଋଳ͔ΒਫฏʹҠྲྀ͞Ε࣪౓ͱͱ΋ʹࣔͨ͠΋ͷͰ͋Δɻt = 12 h ͔Β 48 hͯདྷ͍ͯΔ͜ͱ͕Θ͔ͬͨɻҰํɼ‫ס‬૩ͨ͠૚ͷۭ‫ؾ‬·Ͱɼઌʹड़΂ͨ 2 ͭͷ૯‫ن؍‬໛ӔͱҌ఺ߏ଄͕‫ܧ‬ଓ͸ೆ͔Βདྷ͍ͯͨɻ·ͨɼ͜ͷཻࢠ௥੻࣮‫ݧ‬ΑΓ࣪తʹ‫ݟ‬ΒΕΔ͜ͱ͕Θ͔ΔɻҌ఺ͷ෦෼Ͱ͸‫ס‬૩ͨ͠५ͳ૚಺ͷۭ‫ࢠཻؾ‬ͷଟ͘͸ւ༸্ͷ‫ڥ‬ք૚͔Βରۭ‫࣪ͱؾ‬५ͳۭ‫͓ͯ͠઀͕ؾ‬Γɼͦͷۭ‫ؾ‬մ͕๺౦–ྲྀʹΑ্ͬͯ࣋ͪ͛ΒΕͯདྷ͍ͯΔ͜ͱ΋Θ͔ͬͨɻೆ੢ํ޲ʹҾ͖৳͹͞Ε͍ͯΔ༷ࢠ͕‫ͱͯݟ‬ΕΔɻ͜ΕΒͷ݁Ռ͸ Shiotani et al. (2002) ʹΑΔɼ࣪५ͳ૚ͷۭ‫͕ؾ‬೤ଳऩଋଳ͔Β༌ૹ͞Ε͖͍ͯͯΔͷͰ ·ͱΊ͸ͳ͍͔ͱ͍͏ࣔࠦΛཪ෇͚Δ΋ͷͰ͋Δɻཻࢠ‫܈‬Λ౦੢Ԗ௚໘಺ʹ֨ࢠঢ়ʹ഑ஔͨ͠લํཻ౦෦ଠฏ༸੺ಓҬͰ 1999 ೥ͷর༸‫؍ؙ‬ଌͷࡍʹ‫ݟ‬ࢠ௥੻࣮‫ʹݧ‬ΑΓɼ૚ঢ়ߏ଄͕౦੢ํ޲ʹ΍΍܏͍ΒΕͨ૬ର࣪౓ͷ૚ঢ়ߏ଄ʹ͍ͭͯௐ΂ΔͨΊʹɼྖ͍ͯΔ͜ͱ͕Θ͔ͬͨɻ·ͨɼྲྀઢղੳΑΓ੢‫ ܦ‬120Ҭେ‫ؾ‬Ϟσϧ MM5 Λ༻͍ͯ਺஋࣮‫ݧ‬Λߦͬͨɻͦͷ౓ɼ๺Ң 8 ౓ɼ͓Αͼɼ੢‫ ܦ‬90 ౓ɼ๺Ң 5 ౓෇ۙʹ݁Ռɼ೤ଳऩଋଳͷೆଆͷߴ౓ 5 km ෇ۙʹ૬ର࣪౓Ґஔ͢Δೋͭͷ૯‫ن؍‬໛Ӕͷؒʹ͋ΔҌ఺͕ࡾ࣍‫ݩ‬ͷߴ͍૚ঢ়ߏ଄͕࠶‫͞ݱ‬ΕͨɻԖ௚ϓϩϑΝΠϧͷతͳ૚ঢ়ߏ଄ͷ‫ܗ‬੒աఔʹՌͨ͢໾ׂ͕໌Β͔ʹͳͬಛ௃͸র༸‫؍ؙ‬ଌʹ͓͍ͯ‫؍‬ଌ͞Εͨ૚ঢ়ߏ଄ͷ΋ͨɻ૚ঢ়ߏ଄ͷ؇΍͔ͳ܏͖͸૚ঢ়ߏ଄ΑΓ্ʹ͓ͷͱࣅ͍ͯΔɻ૚ঢ়ߏ଄ͷ͏ͪ࠷΋໘ੵͷେ͖͍͔͍ͯҌ఺ͷҐஔ্͕΄Ͳ੢ʹͣΕ͍ͯΔ͜ͱʹ‫ى‬Ҽͨ·Γ͸౦੢εέʔϧ͕໿ 1000kmɼೆ๺εέʔϧ͕͢Δ͜ͱ͕Θ͔ͬͨɻࠓͷ࣌఺Ͱ͸ɼೋͭͷӔͱҌ఺໿ 400kmɼԖ௚εέʔϧ͕ 1ʙ2km Ͱ͋ͬͨɻ૚ঢ়ͷ‫ܗ‬੒աఔʹ͍ͭͯ͸໌Β͔Ͱͳ͍ɻ

ߏ଄ͷ͔ͨ·ΓΛ‫ܗ‬੒͢Δ࣌ؒεέʔϧ͸໿ 1ʙ2 ೔Ͱ͋ͬͨɻҰൠʹɼബ͍૚ঢ়ߏ଄͸ɼߏ੒͢Δۭ‫ؾ‬մ͕‫ݩ‬ʑͲͷΑ͏ͳۭ‫ؾ‬մͰ͔͋ͬͨͱ͍͏ҙຯͰͷʮ‫ݯى‬ʯ͕Ԗ௚ʹް͍΋ͷ͔ബ͍΋ͷ͔ɼʹΑͬͯ෼ྨͰ͖

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ํɼۭ‫ؾ‬մͷ‫͕ݯى‬ബ͘ͳͯ͘΋ɼ॥‫؀‬৔͕‫͍ڧ‬Ԗ

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Numerical Experiments on the Layered Structures in the Tropical Mid-Tropospherewith a Regional Atmospheric Model
Shigenori OTSUKA and Shigeo YODEN
Graduate School of Science, Kyoto University, Kyoto, JapanSynopsis
We performed numerical experiments on layered structures in the tropical mid-troposphere, which are often
observed by radiosonde and airborne observations as anticorrelation between humidity and ozone, with a regional
atmospheric model in order to investigate their three-dimensional structure and material transport processes. We
reproduced a thin layered structure of high humidity, which has a horizontal scale of about 1000 km and a verticalextent of about 1 km. Particle transport experiments around the layered structure show that wet part of the layered
structure is advected from the intertropical convergence zone by northwesterly winds, while dry parts above and below
it come from southeast direction. Streamline analysis shows that the reason why the thin layered structure is producedis that a stagnation point between two synoptic-scale vortices shifts longitudinally with height.

Keywords: inter tropical convergence zone, mid-troposphere, layered structures