Ja-Yeon Moon

Center for Climate Physics, Institute for Basic Science

This study examines the up-to-date observed trends of subseasonal to annual range climate extremes over the East Asia region using the high-resolution global unified gauge-based analysis of the NOAA Climate Prediction Center for 1981-2021. The spatial extent of extreme events is identified using the Expert Team on Climate Change Detection and Indic...

Previous studies have shown that sea ice loss over the Barents-Kara Seas (BKS) in early winter intensifies surface warming and favors more frequent Ural blocking (UB). Using three different blocking detection methods based on reanalysis and model simulation, we find that the increased occurrences of UB and Kamchatka blocking (KB) over Eurasia are c...

Understanding heavy fire activities tied up to climate and its future change is of emerging scientific concern and essential for reducing huge economic costs and life losses from substantial heavy fire hazards under greenhouse warming. Madden-Julian Oscillation (MJO) is a planetary-scale tropical convective system and moves from Asia to the US, gen...

Northward propagation of the boreal summer intraseasonal oscillation (BSISO) system over the Indian Ocean significantly affects Asia summer monsoon and extreme weather events including typhoons but many climate models poorly simulate the norward movement of BSISO. Here, we suggest that the modified parameterizations can improve BSISO northward prop...

A Madden–Jillian oscillation (MJO) and boreal summer intraseasonal oscillation (BSISO) are important climate variabilities, which affect a forecast of weather and climate. In this study, the MJO and the BSISO hindcasts from the Global Seasonal Forecast System, version 5 (GS5) were diagnosed using dynamic-oriented theories. We additionally analyzed...

In 2018, heatwaves (HWs), which are defined as period of abnormally hot weather with the daily maximum temperature (T_Max) exceeding its 95th percentile threshold for at least three consecutive days, were prevalent during June to August, and temperature records were broken in many countries over East Asia (EA) including China (CH), Japan (JP), and...

An intraseasonal genesis potential index (ISGPI) for Northern Hemisphere (NH) summer is proposed to quantify the anomalous tropical cyclone genesis (TCG) frequency induced by boreal summer intraseasonal oscillation (BSISO). The most important factor controlling NH summer TCG is found as 500-hPa vertical motion (ω500) caused by the prominent northwa...

The prediction skill for the East Asian winter monsoon (EAWM) has been analyzed, using the observations and different climate models that participate in the APEC Climate Center (APCC) multi-model ensemble (MME) seasonal forecast. The authors first examined the characteristics of the existing EAWM indices to find a suitable index for the APCC season...

Prediction of extreme weather events two-to-six weeks ahead has immense social-economic benefits for hazard prevention and risk management as well as economic planning. Physical basis for such subseasonal prediction is primarily rooted in the intrinsic predictability of large-scale circulation associated with the tropical intraseasonal oscillation...

Modulation of tropical cyclone (TC) genesis by the Madden-Julian oscillation (MJO) has been quantitatively diagnosed by using a climatological genesis potential index (GPI). Analysis of TC genesis during November-April of 1979-2014 indicates the most effective factors controlling intraseasonal TC genesis are 850-hPa relative vorticity weighted by t...

The boreal summer intraseasonal oscillation (BSISO) is one of the most prominent modes in the tropical climate system. For better subseasonal prediction of extreme precipitation the relationship between BSISO activity and extreme precipitation events (days with daily precipitation exceeding the local 90th percentile) over Asia is investigated, espe...

Conceptual models to analyze both typhoon and Changma using products extracted by the GEO-KOMPSAT-2A (GK-2A) are suggested in this study. The GK-2A which is scheduled to be launched in 2018 has a high resolution, 16 channels, and 52 products. This means GK-2A is expected to obtain high quality images and products, which can detect severe weather ea...

In this study, we analyzed the characteristics of summer rainfall over South Korea during recent five(2009-2013) years using observation data. There was a significant contrast in interannual variability between July and August rainfall since 1998. Large increase of rainfall in July (2009 and 2011) and August (2010 and 2012) were found to be consist...

How well the climate models simulate extreme temperature over East Asia and how the extreme indices would change under anthropogenic global warming are investigated. The indices studied include hot days (HD), tropical nights (TN), growing degree days (GDD), and cooling degree days (CDD) in summer and heating degree days (HDD) and frost days (FD) in...

The boreal summer intraseasonal oscillation (BSISO) has strong convective activity centers in Indian (I), Western North Pacific (WNP), and North American (NA) summer monsoon (SM) regions. The present study attempts to reveal BSISO teleconnection patterns associated with these dominant intraseasonal variability centers. During the active phase of IS...

During the winter of 2009/10, a number of record-breaking snowfall events registered in the eastern United States are shown to have been modulated by the pulsation of tropical MJO through an atmospheric teleconnection pattern. The intraseasonal variability over the eastern subtropical Pacific near Mexico (the equatorial central Pacific) had reached...

The extratropical teleconnections associated with Madden–Julian Oscillation (MJO) are shown to have an action center in the North Pacific where the pressure anomalies have opposite polarities between the Phase 3 (convective Indian Ocean) and Phase 7 (convective western Pacific) of the MJO. The teleconnection in the same phase of MJO may induce oppo...

Using the techniques of empirical orthogonal function analysis and the change-point analysis to total summer rainfall from 60 weather observation stations, it was found that total summer (from June to September) rainfall in Korea has increased greatly since 1998. The increase level was higher in the season between Changma and late summer rainy seas...

This study has developed a multiple linear regression model for the seasonal prediction of the summer tropical cyclone genesis frequency (TCGF) in the western North Pacific using the three teleconnection patterns. These patterns are representative of the Siberian High Oscillation (SHO) in the East Asian continent, the North Pacific Oscillation in t...

The global time slice approach is a transient experiment using high resolution atmosphere-only model with boundary condition from the low resolution globally coupled ocean-atmosphere model. The present study employs this "time slice concept" using ECHAM4 atmosphere-only model at a horizontal resolution of T106 with the lower boundary forcing obtain...

The interannual variability of sea surface temperature (SST) in the tropics induces changes in global-scale atmospheric circulation not only in seasonal-to-interannual time scale but also in sub-seasonal time scale such as Madden-Julian Oscillation (MJO). The present study investigates the response of Northern Hemisphere (NH) atmospheric circulatio...

Meteorological Research Institute (METRI) multi model ensemble system for seasonal prediction has been established with four different climate models. Multi model hindcast ensemble experiment from 1979 to 2002 by using the same initial and boundary condition is performed for winter season. To evaluate seasonal predictability of linear multi model e...

Boreal wintertime extratropical circulation is studied in relation to the tropical convection during the 1982/83 El Niño and 1988/89 La Niña. The anomaly structure of 1982/83 and 1988/89 over the extratropics reveals remarkably different features as the longitudinal tropical forcing region changes. The Rossby wave source (Positive) shows the larges...