Interannual Variability of Dust Deposition in Japan 1 during Spring Season and Related Atmospheric 2 Circulation Fields

Abstract


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Mineral dust particles affect health, climate, and ecosystems in various ways. These 58 It affects regional climate via the aerosol-radiation (both shortwave and longwave) and    One of the goals of this study is to assess the separate contribution of cyclonic and 156 anticyclonic winds to dust transport. In diagnosing the dust transport by wind, the horizontal 157 dust flux is defined as follows: 168 where is the curvature radius and is the scalar wind speed. Subscripts and 169 denote partial derivatives with respect to the longitude and latitude, respectively. Curvature  Japan.

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If we pay attention to the difference between the circulation anomalies associated with 233 the Domains 1 and 2 variations, the anomalous trough in the Domain 1 anomaly was 234 centered at the eastern coast of the Asian continent (Fig. 3c), and significant wind anomalies 235 (purple vectors) were only toward western Japan (Fig. 3e). Meanwhile, the cyclonic anomaly 236 of Domain 2 shifted northwestward from that of Domain 1 (Fig. 3d), and significant wind 237 anomalies were toward northern Japan (Fig. 3f). Figure 4 shows the difference between the Plateau. Moreover, the anomalous westerlies were indicative of the intensified eastward dust 251 transport (Fig. 5a). The anomalous descent was significantly confirmed over 120-140°E in 252 the lower to middle troposphere, which may be favorable to dust deposition. As for the cross-253 section along with the dust source regions toward Domain 2 (Fig. 5b), the higher-than-254 normal dust concentration over the western Mongolian Plateau (Gobi Desert; 100-120°E) 255 was consistent with the anomalous dust emission (Fig. 2). In contrast, the dust concentration

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The complex processes for aerosol may be responsible for the non-significant anomalies of 265 the dust concentration in the lower troposphere over Japan. can carry the dust more northward in comparison with the non-significant anomalies for the 295 Domain 1 variability (Fig. 6a). In contrast, the extratropical cyclone activity was suppressed 296 over the center of its climatological maximum (negative regression coefficients in Fig. 6).

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The northeast-southwest pair of the negative and positive LDR anomalies was consistent 298 with the SLP anomalies ( Figs. 3a and b). It is suggested that the anomalous extratropical 299 cyclone activity may be also responsible for the increase of the dust concentration and 300 deposition around Japan through the intensified dust transport. Peninsula to Japan was significantly intensified (Figs. 7c and e), bearing resemblance to the 327 stationary wind anomalies (Fig. 3). The slight regional difference of the significant zonal flux 328 anomalies between Domains 1 and 2 (gray shading, Figs. 7c and e) could be responsible 329 for each regional increase of dust deposition. The anticyclonic dust flux also seemed to be 330 stronger than normal, especially in the Domain 2 variation (Fig. 7f). However, we cannot find 331 significant anomalies for the Domain 1 variation (Fig. 7d). bore a striking resemblance to the whole mean deposition (Fig. 1a), implying that the wet  northeastern China and the related strong dust transport by westerlies (Fig. S4b, c).

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It is well known that interannual climate variability is highly affected by global  As for the analysis of the extratropical cyclones, our result implied a relationship between 431 bomb cyclones and the dust deposition variation in Japan (Fig. 6). To verify the influence of 432 bomb cyclones on dust transport to northern Japan is awaited. Furthermore, recent studies