17:15 〜 19:15
[ACG45-P01] Long-term variability of precipitation systems in the northeastern Indian subcontinent and the Indochinese Peninsula
キーワード：intraseasonal oscillation、monsoon、pre-monsoon
This study aims to collect surface rainfall data in the study area, create an Asian monsoon rainfall database, and make the database available on a repository site for use in other studies with the approval of each working institution, as well as to experiment with long-term trend analysis such as seasonal cycles. The database to be developed in this study will cover a longer period (57 years for APHRO_V1101) than APHRODITE (Yatagai et al., 2012), allowing for longer term analysis. Furthermore, we will verify the created Asian monsoon rainfall database using satellite observation data (e.g. TRMM) and existing rainfall products (e.g. APHRODITE), while confirming whether the seasonal progression is like the results of previous studies. The purpose of this study is also to examine whether the database is accurate enough to achieve the research objectives of this study. In this report, we present the results of the trend analysis around the state of West Bengal, India, which was finally accepted for publication.
Under changing climatic conditions, past (1976-2006) and future (2071-2100) trends were evaluated for the onset, withdrawal and duration of the Indian summer monsoon. First, historical precipitation data (APHRODITE) observed over the Indian subcontinent were analyzed to determine trends in the onset, withdrawal, and duration of the monsoon. In several regions, the historical data showed an earlier onset and longer duration of the monsoon, and a later withdrawal of the monsoon. In the northeastern part of the Indian subcontinent, such trends in monsoon onset and duration were pronounced. Several climate models in the Fifth Coupled Model Intercomparison Program (CMIP5) were able to capture past trends detected in the observational data, and five models were selected for analysis of future periods; the future projections of the CMIP5 models under the RCP8.5 scenario, although weakly statistically significant, showed that the monsoon similar trends for the onset, withdrawal, and duration of the monsoon, although the statistical significance is weak. This result suggests that the trend observed in the past for earlier onset and later withdrawal of the monsoon will continue in the future, with longer durations.
In this study, the relationship between ground-based and satellite observation data was verified. Trend analysis was also conducted for India, and the results indicated that the past observed trend of earlier onset and later withdrawal of the monsoon will continue in the future, and that the duration of the monsoon rainy season will be longer.
Under changing climatic conditions, past (1976-2006) and future (2071-2100) trends were evaluated for the onset, withdrawal and duration of the Indian summer monsoon. First, historical precipitation data (APHRODITE) observed over the Indian subcontinent were analyzed to determine trends in the onset, withdrawal, and duration of the monsoon. In several regions, the historical data showed an earlier onset and longer duration of the monsoon, and a later withdrawal of the monsoon. In the northeastern part of the Indian subcontinent, such trends in monsoon onset and duration were pronounced. Several climate models in the Fifth Coupled Model Intercomparison Program (CMIP5) were able to capture past trends detected in the observational data, and five models were selected for analysis of future periods; the future projections of the CMIP5 models under the RCP8.5 scenario, although weakly statistically significant, showed that the monsoon similar trends for the onset, withdrawal, and duration of the monsoon, although the statistical significance is weak. This result suggests that the trend observed in the past for earlier onset and later withdrawal of the monsoon will continue in the future, with longer durations.
In this study, the relationship between ground-based and satellite observation data was verified. Trend analysis was also conducted for India, and the results indicated that the past observed trend of earlier onset and later withdrawal of the monsoon will continue in the future, and that the duration of the monsoon rainy season will be longer.