Colored Moisture Analysis Estimates of Variations in 1998 Asian Monsoon Water Sources

Abstract

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.

An estimation of water origins in the vicinity of a tropical cyclone’s center and associated dynamic processes

“…We conducted a colored moisture analysis (CMA), developed by Yoshimura et al (2004), to track the origins of water within the TC system. This method can help us to understand how water vapor from specific regions is remotely transported.…”

“…This partition is almost the same as that in K2014, which makes it possible to properly compare between the ICM used in K2014 and IsoRSM results, and we exclude the continental region and the oceanic region with no relation to the MCB. To validate the IsoRSM results obtained by this study, we utilized the stable oxygen isotope ratio (δ 18 O) data of the precipitation observed on a daily basis, following the precedent established by Yoshimura et al (2004).…”

Validating a regional climate model’s downscaling ability for East Asian summer monsoonal interannual variability

“…The results from the GSWP experiment apparently show the best performance. Over the Mongolian region, more than 80 % of precipitation during May to October in 1998 comes from the evaporation around that area (Yoshimura et al 2004). Sato et al (2007a) has also shown that a large portion of atmospheric moisture is supplied as a result of evapotranspiration from the land surface over inland areas like Mongolia.…”

Intraseasonal Variability of δ¹⁸O of Precipitation over the Indonesian Maritime Continent Related to the Madden–Julian Oscillation

“…Furthermore, Yoshimura et al (2003) successfully developed a Rayleigh-type isotope circulation model (ICM) using meteorological forcing data and reproduced the observed daily variability of precipitation isotopes. Yoshimura et al (2004) used the ICM to develop an atmospheric water vapor transport model to estimate vapor advection from specific source regions using colored moisture analysis (CMA). The ICM/CMA considers the vertical structure of the atmosphere as a single layer in which the vertical profiles of water and isotopic composition are vertically integrated.…”