著者

Kei YOSHIMURA Taikan OKI Nobuhito OHTE Shinjiro KANAE

出版者

Meteorological Society of Japan

雑誌

気象集誌. 第2輯 (ISSN:00261165)

巻号頁・発行日

vol.82, no.5, pp.1315-1329, 2004 (Released:2004-12-17)

参考文献数

33

被引用文献数

56 85

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This study investigated the dynamic motion of atmospheric water advection by an analytic method called colored moisture analysis (CMA), that allows for the estimation and visualization of atmospheric moisture advection from specific source regions. The CMA water transport model includes balance equations with the upstream scheme and, uses external meteorological forcings. The forcings were obtained from the Global Energy and Water Cycle Experiment (GEWEX) Asian Monsoon Experiments (GAME) reanalysis. A numerical simulation with 79 global sections was run for April to October 1998. The results clearly showed seasonal variations in advection associated with large-scale circulation fields, particularly a difference between rainy and dry seasons associated with the Asian monsoon. The paper also proposes a new definition of southwest Asian monsoon onset and decay, based on the amount of water originating from the Indian Ocean. Earliest onset occurs over southeastern Indochina around 16- 25 May. Subsequent onset occurs in India one month later. These results agree with previous studies on the Asian monsoon onset/end. The CMA provides a clearer, more integrated view of temporal and spatial changes in atmospheric circulation fields, particularly Asian monsoon activities, than previous studies that focused only on one or two distinct circulation features, such as precipitation or wind speed. Furthermore, monsoon transition in a specific year, 1998, first became analyzable, whereas the previous studies used climatologies.

著者

Ai Hiraoka Ryuichi Kawamura Kimpei Ichiyanagi Masahiro Tanoue Kei Yoshimura

出版者

Meteorological Society of Japan

雑誌

SOLA (ISSN:13496476)

巻号頁・発行日

vol.7, pp.141-144, 2011 (Released:2011-09-22)

参考文献数

11

被引用文献数

7 7

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By applying the Japanese long-term Re-Analysis project (JRA-25) and the Japan Meteorological Agency Climate Data Assimilation System (JCDAS) data to a Rayleigh-type global one-layer isotope circulation model, we performed a long-term simulation and examined how water vapor is remotely transported to the vicinity of Japan from water source regions during the early summer rainy (Baiu) season. We validated the model outputs, comparing them with the stable hydrogen and oxygen isotope ratios (δD and δ18O) of precipitation observed at two in situ sites in southern and central Japan during the 2010 Baiu, and determined that the correlations between the simulation and observation are comparable to those in precipitation in Thailand from August to October when the Asian summer monsoon withdraws. The model results demonstrate that the Baiu is characterized by relatively low values of δD and that the δD values over central Japan are lower than those over southern Japan. When the Baiu commences, Indian Ocean water increases rapidly and then contributes substantially to the total precipitable water until the withdrawal of the Baiu, which is partially responsible for the low values of δD. Once the Baiu withdraws, alternatively, Pacific Ocean water occupies most of the total precipitable water. Another signature of its withdrawal is the decrease in land water of the Eurasian continent. It is also clear that the intrusion of the Indian Ocean water into central Japan remained until the end of August in the extremely cool summers of 1993 and 2003, which is interpreted as an extraordinary persistence of the Baiu period.

著者

Inna Syafarina Arnida Lailatul Latifah Yosuke Miura Tomoko Nitta Kei Yoshimura

出版者

Japan Society of Hydrology and Water Resources (JSHWR) / Japanese Association of Groundwater Hydrology (JAGH) / Japanese Association of Hydrological Sciences (JAHS) / Japanese Society of Physical Hydrology (JSPH)

雑誌

Hydrological Research Letters (ISSN:18823416)

巻号頁・発行日

vol.15, no.4, pp.98-104, 2021 (Released:2021-12-04)

参考文献数

32

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The surface water formation parameter (Kw) currently used in malaria transmission models can dramatically affect larval development calculations. However, the parameter is often unrealistic due to the unavailability of observational datasets. This research presents an adjusted Kw by reference to an entomological inoculation rate (EIR) over the period 1983–2006, tuning the parameter by minimizing root mean square deviation of the water fraction from model calculations and satellite observations from 2014–2018. A scaling factor, topography factor, and inverse distance weighting were used to reduce the gap between macro- and microscales and to derive the appropriate spatial distribution of Kw for a projection period from 2020–2100. The average EIR over the projection period under Representative Concentration Pathway (RCP) scenarios 2.6, 7.0, and 8.5 in West Africa decreased by –29%, –43% and –35%, respectively, from the historical period. By contrast, for central southern Africa, the respective values increased by 3%, 6%, and 29% from the historical period. The reduced EIRs under RCPs 7.0 and 8.5 in West Africa were mostly affected by temperature, while monthly mean precipitation triggered a decrease in EIRs under RCP 2.6. By contrast, consecutive wet days have the most influential role in increasing the EIR in central southern Africa under all RCP scenarios. This research will help policy-makers eradicate vulnerable malaria areas and improve related policy design.

著者

芳村 圭 Kei Yoshimura

出版者

一般社団法人 人工知能学会

雑誌

人工知能学会誌 = Journal of Japanese Society for Artificial Intelligence (ISSN:09128085)

巻号頁・発行日

vol.21, no.6, pp.724-726, 2006-11-01

被引用文献数

1