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The Northeastern Pacific climate system is featured by a large-scale low-cloud deck off California on the southeastern flank of a subtropical high, which accompanies intense northeasterly trade winds and relatively low sea-surface temperature (SST), especially in the warm season. The climatic impacts of the low cloud deck are investigated by turning low-cloud radiative forcing on and off only within the subtropical Northeastern Pacificin a coupled atmosphere-ocean model. The radiative forcing lowers SST locally by as much as 3ºC, and the low-cloud impacts on the North Pacific subtropical high are found to maximize in summer under the seasonally enhanced insolation. In combination with the seasonally shallow ocean mixed layer, the SST decrease by low clouds off California peaks in summer, suppressing deep convective precipitation that would otherwise occur in the absence of the low-cloud deck. The resultant anomalous diabatic cooling induces a surface anticyclonic response in summer and autumn as a baroclinic Matsuno-Gill pattern. The consequent enhancement of the trade winds on its equatorward flank leads to further SST lowering that extends southwestward through the wind-evaporation-SST feedback. The enhanced trade winds accompany intensified upper-tropospheric westerlies, strengthening the vertical wind shear that, together with lowered SST, acts to shield Hawaii from powerful hurricanes. On the basin scale, the surface anticyclonic wind response accelerates the North Pacific subtropical ocean gyre to speed up the Kuroshio by as much as 30%. Thus, SST increases along the Kuroshio and its extension, intensifying upward turbulent heat fluxes from the ocean with increased precipitation., The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)

To utilize the reanalysis for the social benefit, we need to increase the horizontal resolution for the better representation of local meteorological fields. While JMA will provide the JRA-3Q global reanalysis with the horizontal resolution of 40km in 2022, we plan to produce the regional reanalysis with 5km resolution under ClimCORE (Climate change actions with CO-creation powered by Regional weather information and E-technology). For the regional reanalysis, we will also re-produce the 1km mesh precipitation data over Japan analyzed by radar and rain gauge data.

Three radioactive microparticles were separated from particles on filter tape samples collected hourly at a suspended particulate matter (SPM) monitoring site located at ∼25 km north of the Fukushima Daiichi Nuclear Power Plant (FDNPP), after the hydrogen explosion of reactor 1 on 12th March 2011. The 134Cs/137Cs radioactivity ratios of the three radioactive aerosol particles showed that they were derived from the FDNPP reactor 1, rather than reactors 2 or 3. The physical characteristics of these particles with < 10 μm in diameter and non-uniform shape are clearly different from those of radioactive particles generated by the hydrogen explosion of the FDNPP reactor 1. A significant amount of Cl was detected by energy dispaersive X-ray spectrometery. Synchrosron radiation microbeam (SR-μ-) X-ray fluoresence (XRF) analysis showed that these particles contain a series of heavy elements related to the nuclear fules and their fission products with a non-homogeneous distribution within the particles. In addition, the SR-μ-XRF identified trace amounts of Br in these particles; the element has firstly been found in radioactive particles derived by the FDNPP accident. In contrast to the hydrogen explosion-generated radioactive particles containing Sr and Ba, both of which are easily volatile under a reduction atmosphere, these elements were not rich in the particles found in this study. By the SR-μ-X-ray absorption near edge structure analysis and SR-μ-X-ray powder diffraction, it was found that these particles consist of an amorphous (or low crystalline) matrix containing metal elements with chemical states in a comparatively high state of oxidation or chloride. Based on these physical and chemical characteristics and a trajectory analysis of air parcels that passed over the SPM monitoring site, we concluded that these radioactive particles were generated and emitted into the atomosphere at the time of seawater injection for cooling the reactor after the hydrogen explosion.

Additional file 1: Table S1. 134Cs and 137Cs radioactivities and 134Cs/137Cs activity ratio of eight particles (A1~G1). Figure S1. SR-μ-XANES spectra of four representative CsMPs (A1, B1, C1, and E1) isolated from the SPM filter and reference materials. (a) Fe-K edge, (b) Zn-K edge, (c) Mo-K edge, and (d) Sn-K edge. Figure S2. SR-μ-XRD patterns of four representative radioactive particles (A1, B1, C1, and E1) isolated from the SPM filter and reference material. (a) Particle A1, (b) particle B1, (c) particle C1, (d) particle E1, and (e) silicon powder (NIST SRM 640c). In contrast to sharp diffraction peaks detected in silicon powder, no obvious peaks were detected in four radioactive particles.

平成24年度京都大学防災研究所一般研究集会(24K-08)「週間及び1か月予報における顕著現象の予測可能性」, 京都大学防災研究所連携研究棟大セミナー室, 2012/11/20-22

平成24年度京都大学防災研究所一般研究集会(24K-08)「週間及び1か月予報における顕著現象の予測可能性」, 京都大学防災研究所連携研究棟大セミナー室, 2012/11/20-22

平成24年度京都大学防災研究所一般研究集会(24K-08)「週間及び1か月予報における顕著現象の予測可能性」, 京都大学防災研究所連携研究棟大セミナー室, 2012/11/20-22

平成24年度京都大学防災研究所一般研究集会(24K-08)「週間及び1か月予報における顕著現象の予測可能性」, 京都大学防災研究所連携研究棟大セミナー室, 2012/11/20-22

A high-altitude project of the RIHN established an automatic weather station (AWS) at Domkhar (76.82E, 34.45N, 3808m) in Ladakh in June 2009. The AWS captured rainfall events in early August that caused flooding and mudslides in Ladakh. At the conference, we present 1)general meteorological features observed by the AWS, 2)time series of rainfall in early August, and 3) synoptic/continental scale circulation fields associated with 1) and 2). There was flooding in Ladakh from 4 to 8 August. Our rain gauges in Leh and the AWS recorded mid-night rainfall for this period. The hourly rainfall at the peak time (0:13 – 1:13AM of 6th ) in western and northern Leh were 15 and 7 mm/hr, respectively. They are not that much greater than rainfall reported in a local newspaper. Large differences between the two summers were found in pentad 34 (5–9 June) and pentad 44 (4–8 August). In pentad 44, the precipitation, north–south wind and humidity differed for 2009 and 2010, with there being flooding in 2010. From 4 to 8 August of 2010, at 500 hPa level, moist air from the south are observed over Afghanistan, north Pakistan, and the western part of the Tibetan Plateau.