%tmmM>$- &m%L% 1982―83^(7);t-X inf 1988^11^ Y?V T<D=fW￡ Behavior of dust clouds from Australian dust storms in 1982-83 as observed by the GMS N. Murayama Abstract Dust clouds observed by the GMS Australia (hereafter NG examined as a bright area between New Guinea dust clouds) in the spring (in the southern hemisphere) and the north of 1982 were in relation to the great drough of Australian continent. The time serialGMS visible imageries were surveyed for the period of June 1982 to February 1983 to find out the dust storms and the dust clouds distant from its source area and their connection. It was ascertained that NG dust clouds were transported mainly along with the southeasterly trades and partiallyfrom the north Australia and then stayed there in relation with convergent condition forming eddy-like and/or wave of dust clouds. Westward movements of the wavy dust clouds extended to the west over Indonesia. 20°N across the equator accompanying wind and/or calm pattern. Eddy and waves can help verticalthickening dust clouds are in about 20km/h. Then the A part of the dust cloud was transported to by a movement of the typhoon and also 20°Salong with an incidental northeasterly wind. 1. ￡*## 1982^ 9 ―11J3 c GMS ￡J$rT8IH≫￡ JIS ￡ S, 140*E ffifi(-*-＼-7 10° > ISc-9-y^ SfS8B)K^ ￡￡Tf±1982^6 ￡ HR-FAXi!#!H￡fflbT> ^ 1000kmX500kmSgOJE*5t))*J% S O#*M?> ti^o 1982 83^ti 1982―83^c^--X CjBH-tS^^ h≫"C*5a b 7 'J7fIC i ■2>#ffiHc Lffttfttl?ltT^ EL Nin6 mMHtiMQ^- 2. 1982 c fj (1982^1OH1O0 83^3 HOlPICGMSO :c/X hSc;pKl￡fI fcJS^L^o ^10^^ *J ≪tt/205 : 00UT VIS) &J3Vfo - c%^≪m^tiffl*^c 83^<7)^--A h v U T7c^^ 1982^ 4 c GMS/ 1/3) ciot, 6 ^ *^,^ i ^-rnmrn t^^m ^--x h7 y rsspaioo^K (＼^c isc J:- 6 "CM c^*^J￡c^^J^^LTVi§ (Bureau of Meteorology)o ztuzzz t&^zfctfZWMm^Tti: < M%$ c#IS≪lftc^*s§T;Lv^Ji^*oA:il Meteorologial SatelliteCenter -85- t*sfc*^o METEOROLOGICAL SATELLITE CENTER TECHNICAL NOTENo.17 NOVEMBER 1988 ,-**^*H￨ r ..4 1 ±.*m 4 f Ul FT* 17T a H a n s rw s S Rl h r^ FT R I E a m Ffl Fi e^ 1 r^ Z] Pv Fig.la) Examples of GMS visibleimageries (NovlO and 20: 00UT) show- ing the oval-shaped bright area between New Guinea and the north Australia. This was firstsuspected to the dust clouds caused by the Australian drought in 1982. 86- 9Lm.mm-z>*- &mm￡ nn* ims^hj! IS ≪￡―- - MlN ■ IOIO-25 ･≫￡*'1030 V. ^ ' A X 3 B Fig. lb) Streamline chart of surface (A) and 700mb (B) on November 19, 1982: 00 UT prepared by the Darwin Meteorological Office, AustralianBureau of Meteorology. This is only an available meteorological data and leads to a thought that the dust cloud relates with a large eddy persistent. Area of the charts is the same as in Fig 1 (a). (courtesy of Bureau of Meteorology and Dr. G.W. Paltridge, CSIRO). -87- METEOROLOGICAL SATELLITE CENTER TECHNICAL N0TENal7 NOVEMBER 1988 った。Ｒｌｎｆａｌ１吻fic1●ncils based ？●1e･rrapriic on FspocC a Selahttp://www.f これらのダスト雲はオーストラリア大陸から直接運！S t a U Q n l ばれて来たものであろうか？干航地域すなわち砂塵嵐発生可能域は主として中緯度の偏西風帯にある。そこで初め偏西風で太平洋上へ運ばれ、それから南東貿易風に捕えられて、ニューギニア南部に達するのが最も多い場合と考えられる。 ECMWF発刊の850mb風解析図（水平分解能300km)を使い、ダスト雲の広がりと風の対応をとった。第３図にその例を示す。 10月23日（３図右下）はダスト雲が南東から北西へ 4000∼5000kmも延びていて、全体の明るさは減少している。ちょうど偏東貿易風にダストが乗った形をしていて、オーストラリア東部から海上へ出たダストが偏東貿易風によって赤道へ運ばれる途中の状態を示しているものと解釈される。干魅の期間オーストラリア大陸の高気圧が高く南東貿易風は通常より強かったと言われている。 10月15日（第３図Ａ）、10月25日（同Ｂ図）、11月10日（同Ｃ図）ともうず状を呈し、気流の収東城の位置している。うずの中心に相当する部分の明るさは一段低くダストは薄く、周辺の方が明るく、したがってダストが濃くみえる。すなわち気流の収東城にできる大規模なうずにダストがとり込まれ、錐直方向に累積して、したがって上空から見たときダストが Fig. 2 Rainfall deficiency (from Ａ Drought Watch in 1982-82 System 濃く見える(eddy-enhanced)と考えられる。うずの回 in Australia 転方向は明瞭でないが時計回りすなわち低気圧既回転 by W.J.Gibbs。ＷＣＰ-134）のようにみえる。歴史的な大干航であり、激しいダストの舞上がりがまたダスト雲はニューギニア島中央を東西に走る山度々生じたであろうことは容易に想像できるが、今ま脈を直接越えて広がることがなく、その南側に止まり、で報告されているものは、1983年２月８日Mesbourne 時に西方から山脈の北側に流れて行くように見える。市を襲った砂塵嵐についてだけに止まっている(Gar- 第４図にニューギェア島の地形の概略を示した（山脈 ratt 1984、 Lourensz の高さは3000ｍ以上のところがある）。このことからダ & Abe 1983）。 3.ニューギニア・北部オーストラリア間のダスト雲スト雲の高さは高くとも3000ｍ以下であると推定できの発現る。ニューギニア島南部とオーストラリア北部の海上に４。砂塵嵐と沿岸からの吹き出し存在したダスト雲（以下ＮＧダスト雲と略称する）は、東西方向に長軸をもつ楕円形をしていることが多ダスト雲の源にあたる砂塵嵐の発生を探るため、く、その明るさの濃淡から大きなうず（1､000knix500 1982年６月∼83年３月の期間について、オーストラリ km程度）にダストが取り込まれたものと推測される。ア東部の強風威を調べ、次にＧＭＳ画像に砂塵嵐を探すなわちeddy した。強風威はECMWF発刊の850mb風解析図（１日 enhanced ダスト雲である。ＮＧダスト雲は、９月末∼12月の間消長を操り返えし、ｎ月が最１回に12UT、水平分解能を300km）の140°Ｅ以東、30° も顕著に見えた｡ＧＭＳ/VIS画像を用いた調査では、７ S以北の区域を対象とし、まず15m/s以上の強風威の月初旬から１月中旬までの間にダスト雲の発生消滅のある日（７月18∼19日、31日、９月８日、15日、29日、消長が起こっていること、ただし10月以降になって初 10月9∼10日、16日、19日、ｎ月17日、25日、12月７めて観測者のだれもが気付くようになったことが分か田を抽出しその日の前後数日間のＧＭＳ画像を調べ、 88 %%mm.M>^- mm& *i7# i988*n/! A 0 2 OS 130E 150E 14CE B 2 OS Fig. 3 850mb wind analysis superposed by the dust clouds on Oct 23 (lower right )and on Oct 15(A),on Oct 25(B) ,and on Nov 10,'82(C) .OnOct23 the dust clouds elongated from the ocean east of Australia to New Guinea and further to NW by southeasterly trades. In (A), (B) and (C), the dust clouds between showed eddy pattern associated with convergence of Equator Topography contours Fig. 4 Topography of New Guinea ty of New 1OOOtn and 2000m Guinea Island. Mountain range is shown by shaded area with contours of 1000 m and 2000 m and more in altitude. -89- METEOROLOGICAL SATELLITE CENTER TECHNICAL NOTENal7 &C1982*￡9 E 83*f 1 ^O^fflWCOVsT GMS jg fcfciKfco GMS/IR iife￡tt&aMLtfttffl* tff. [n]*^-a-400 GMS/VIS 12^6 iR0K ±i:t T*≫^^ h M±^Wl t * t 0 500km*^ (50H) TV^aiv^X tt850mb 9^25 26S (5 HA), 9^29 30B (5 0B) 1988 JH *s -f - Tffi ＼1h flX h**JM?>*i"So ･ tf^ 12^7 0 ^±03iR^A^ b]) rwsas fe^?)tLSo ^§tBt^(n]tt850mbJlJ:^SScUTVi 5o t/clO^l 2 0 (50E) Ctt9^3O0fc￨^i; ^JtJl(20m/si^±) LTU^o fficWHStt50kni 70kmT*4o 19 20S (50FtG) Ji^-f-^^yFWimiBc 190Cttp￨fJ￨gBc-3.―9-^X^7 1000kmc^X - X ･ -^―9-^x>> #SM Cfc-D-C7rV-F^I:^i^200km 2 /! 8 S ;< /u^/uyTU^Ho 3L /i^SJSltt )VX%frhm$) h^;V-AtftoTJlU&ii^gtffco 10 J -90- 0 (501) ^ x ^ x-;uX'J-HSg￨3C*tz*JoTfliailc#4U, $ ^>(C83＼ ^& ttJfclb≫^*'^lS<JS±Ki￡**o H^c15m/s h 7 y 7*n*3b fc NOVEMBER mfciem-tz>*- &w≪& mv^ im*uR F ITl H Y I Ml Dec7 i ! fL<: v' / 7＼＼ ) If 82Iec7 J 3 OS 9 °6 s^f 83Peb9-14 Fig. 5 Outbreak of the dust plumes originated from the dust storms in the east Australia as observed by GMS/VIS for September 1982 to February 1983. The dusts flew from mostly the east coast to the southern Pacific ocean. The case of February 9-14, '83in (J) was associated with the dust storm wall passed Merbourne cityin February 8, 1983. A) Sep 25, '82, B) Sep26.C) Sep 29, D) Sep 30, E) Oct 1-2, F) Oct 19, G) Oct 20, H) Dec 6, I) Dec 7, J) Feb 9-14, '83 -91- METEOROLOGICAL SATELLITE CENTER BK3000km, UGAmim*&*.XiltttM'^tiLtl, TECHNICAL NOTENq17 NOVEMBER 1988 140 Cttl8O*E^ifi02O'N h3OoNKi￨iS^JlOOOkm0lA^ D 5. NG**h*7)l*MttSfl; 1982^10 ll^c2*^Mtt NG ?X hS^^fT Slt＼*sJtlS!W^:SViC:fcKJ:Sfe0i:#^^*i-Bo D 4t＼^c^xhcft& 500kmcl￡*5t)*fcoTViT%*i*5*fcA≫'by-XT **￡*:<, HO'EJ^^C'f >K^5/7±^C*jtc ^b^]500km,mii&lOOOkmOffi^li-nS^oTViSo -^ -^-7^4Mc4kffl!I^^i^^*^Aoa^^<l:■5*^ UA^t^a≪l*#≫^^ (1983^2^160, h^h'j TlE^o TVi-SolOH 1 B*^ 8 HC^lt^Jl21f(T 8221Mac) *5. 10*N#ift*^30'N^t±-f 4 K#v> fcifivtzy* b≫c^bS≫*57 BC15°N, 5 0 HOE 820ct1-8 -92- 9 BKtt23* %&Rm-b>*- mmms m n% 1988*11 j? B 820ct11-13 TP223(0wen) D / ≫ § 20 0ct19 I A 0 20S -93- METEOROLOGICAL SATELLITE CENTER TECHNICAL NOTENq17 F 820ct28-30 820ct25-27 82Nov1-3 J Jr ＼ 82Nov4-7 -94- NOVEMBER 1988 %mmm.M>*- mm& asi7≫ i988*iia 82Nov1>12 L o / / i N 82Nov20-22 -95- METEOROLOGICAL SATELLITE CENTER TECHNICAL NOTENdl7 NOVEMBER 1988 0 26 ＼ </ < -2 82Nov23-26 82Nov27-^0 Fig. 6 Behavior of the dust clouds between New Guinea and the north Australia for October and November, 1982 (in the spring of the southern hemisphere). The dust clouds existed from the early August to the end of December but at the most significantpattern in the spring. A) on Oct 1-9, the dust clouds extended to Insonesia and furtherextended to about 20°N associated with (T8221 Mac). the northward B) on Oct 11-13, and C) on Oct 14-16 there shown between New movement of typhoon an oval-shaped pattern Guinea and the north Australia. D) on Oct 17-21, the similar situation as in A), the northward movement of the dust cloud from New Guinea―Indonesia to the 20°N associated with typhoon (T8223 Owen). E) on Oct 22-23, the dust clouds over the ocean of Australia extended toward WNW to New Guinea by the southeasterly trades. F) on Oct 25-27 and G) on Oct 28-30, the dust clouds between Guinea and the north Australia showed in their southern edge. H) on Nov 1-3, I) Nov between and then moves edge. K) on Nov 4-7, J) Nov New eddy-like and wave-like pattern 8-9, the dust clouds stationed to west with wave-like 10-12 and L) on Nov 13-16, the same pattern of their south as in H), I), and J) except southwestward movement to the east Indian ocean on Nov 15. M) on Nov 17-19 and N) on Nov 20-22, the dust clouds was thickened, those of Nov 17 showed a closed eddy with thin cloud centered and that of Nov 20 streaky pattern, and all those showed their south edge. wave-like pattern oi O) on Nov 23-26 and P) on Nov 28-30, the dust clouds with wavy in theirsouth edee flew westward into their dust clouds. -96- pattern mfcajs-tz>*- 6. ￡JH23-*t(T8223Owen) cjLLCf^, c^K^M^tTV^o 20B^10oNi;t＼ 18 VIttl5*N#ift * T GMS/VIS 2) -f y F#ScaB^c^x 14 15B^ 11H23 /Xhf fcOfi 9 E"HU m^tt lOO'E, 10 20°Scg^ (Bh 14―16B (F). 28-80B 8 20 3 frRmizm 3 R%±Ltzo t tft (J'^^^M t fc0 - c 5 ft≪tt≪Jitt ≪fc 11^ 5 9 H tll^l9 30Sc 2 93￨B￨cNG?'* B hWDMit xyyf-0fcb"CH5ElC^L (M). 12±1Oc 15B 2:26 B ^ Ji20°S izM L § ^>K^^^j^l^^o (J), im*uR 21B IflBLLTMftaj $ *lfc0 VF^om^^JE^D, 3) NG^X mv* boifr&sD 26H^. c^*ja^#oT-f mm% 9 22B ^10^11 (C). (G). B 22 23B 11^ 1-3 (I)> (N). (E). 25 B (Hh 4 10-12B 27 (K). Ncrv 13B 27B 7 //, B 17-19B 30B (P) fc^hilZ 20 NG / yr4taBc≪5±0HiK≪§. V 21 / / y *-xb9yr^au≫# 22 v_ 23 ･ ' J 7 ^io^ 83^ lRmqt-cm**mmt^, mmn 24 ! f V / / / / A Nov5 / 26 ^― / 6 s "X s 27 / / / s 7 / > s＼ >js T, ･ / 8 I y 29 I / 1/ / 9 ^y J /""""^^ 1 130E / 140E 130E HOE Fig. 7 Daily variation of the south edge of the clouds during November 5-9 (A) and November 19-30 (B) suggested that the dust clouds were trapped in by the waves. 28 Westward movements -97- of the wavy pattern were at 30 METEOROLOGICAL SATELLITE ＼-m<D$im<Dmm*mm <ak h 7 7cR^tD^≪jiiSfi, 17km/h CENTER (b) tmum TECHNICAL GMS/VIS NOVEMBER 1988 (± 25km/hkff-￨￨$ b <Dm:&(DR$&* * t tbmmmtLrm 6. VtV ^T NOTENal7 iS^^fflVi-CP^fco 2 ON SI52O-SStllf;ot-Xf7y ―' ^ ＼p-v-ry-A YoJ> vu ＼nr rcr? 8 bk^u, 7*H±≪&aicx m 20N ＼＼ // 0 ＼ w^rs a yiooE ＼yy VTW ＼ 4055 ＼＼ J ＼ ,^r ＼T ＼ / / ^J<^1 170W ＼ <7 100 140 /> 180E Fig. 8 Schematic presentation on the transport routes of the dust clouds originated from the eastern Australia (the area subject to drought in 1982-83 is hatched). The large amount of the dusts outbroken toward the east ocean from the Australian continent is turned to northwest by southeasterly trades, and then, as if the sources exist between New Guinea and the north Australia, the dust clouds moved westward and intermittently moved across the equator to the northern hemisphere associated with the typhoons and also moved toward Indian ocean with incidental northeasterly wind. m -98- & the east part of $HtkRm-b>*- Bureau of Meteorology, Technology, Department 1987 Drought ppl2 in WJ.Gibbs: of Science & Review, A Drought &ffi$8￡ Watch Australia System, WCP-134 Garratt,J. R., 1984 Cold fronts and dust storms during the Australian summer 1982-83. Weather 39, 98-103 Lourensz, R. S., and K. Abe, over Melbourne. Weather 1983 A dust storm 38. 272-275 ' -99- *17* 1988*113