Fig. 2. Lag composite of one-point correlation between observed mean temperature from 11 KMA stations and 2-meter temperature from ERA interim for sampled cold surges. Number n lag days of ERA-interim data with respect to the station observation. Significant values at 99% confidence level are indicated by black dots.
Fig. 3. Composites of geopotential height at 500 hPa (white contour), mean sea level pressure (black contour) and air temperature anomalies (shading) at 100 hPa for the 63 cold surge cases. Contour intervals are 90 m and 4 hPa for 500 hPa geopotential and sealevel pressure respectively. Number on lag indicate days of the analysis data with respect to cold surge days.
Fig. 4. The same with Fig. 3 but for temperature advection at 850 hPa (shaded) and 850 hPa horizontal winds (vector). Dots indicate significant temperature advection at 99% confidence level. Only significant winds at 99% confidence level are presented. The red square is for calculating the averaged temperature advection for Fig. 5.
Fig. 5. Lag composite of temperature advection averaged over the Korean peninsula in Fig. 4. Curves in light gray present the values of individual events.
Fig. 6. Composite of pressure tendency at surface (shaded) and mean sea level pressure (contour) for the cold surge cases. Contour interval is 4 hPa.
Fig. 7. Composites of surface latent (left column) and sensible (right column) fluxs from the ocean. Upward flux from the ocean to the atmosphere is presented as positive.
Fig. 8. Composite of daily mean moisture flux (vector) and moisture convergence (shaded) at 850 hPa one day before the cold surges.
Fig. 9. Composite of temperature tendency by physics heatings (K day−1) at 850 hPa. The red square is for calculating the averaged temperature tendency by the physical heating of Fig. 10.
Fig. 10. Composite of averaged physics heating tendency in the red square in Fig. 9 as a function of height. Light-colored curves denote individual cases.
Fig. 1. (a) Daily mean temperature averaged over 11 KMA station in winter season for period of 1979/80-2016/17. The star (*) denote sampled cold surges. The number of cold day is 63. (b) The number of cold surges (blue bar), Mean temperature anomalies (red line) during the analysis period only winter.
References
- Dee, D. P., and Coauthors, 2011: The ERA-Interim reanalysis: configuration and performance of the data assimilation system. Quart. J. Roy. Meteor. Soc., 137, 553-597, doi:10.1002/qj.828.
- Franzke, C., 2013: A novel method to test for significant trends in extreme values in serially dependent time series. Geophys. Res. Lett., 40, 1391-1395, doi:10.1002/grl.50301.
- Gong, D.-Y., S.-W. Wang, and J.-H. Zhu, 2001: East Asian winter monsoon and Arctic Oscillation. Geophys. Res. Lett., 28, 2073-2076. https://doi.org/10.1029/2000GL012311
- Hoskins, B. J., and P. J. Valdes, 1990: On the existence of storm-tracks. J. Atmos. Sci., 47, 1854-1864. https://doi.org/10.1175/1520-0469(1990)047<1854:OTEOST>2.0.CO;2
- Jeong, J.-H., and C.-H. Ho, 2005: Changes in occurrence of cold surges over east Asia in association with Arctic Oscillation. Geophys. Res. Lett., 32, L14704.
- Jeong, J.-H., B.-M. Kim, C.-H. Ho, D. Chen, and G.-H. Lim, 2006: Stratospheric origin of cold surge occurrence in East Asia. Geophys. Res. Lett., 33, L14710. https://doi.org/10.1029/2006GL026607
- Kim, S.-W., K. Song, S.-Y. Kim, S.-W. Son, and C. Franzke, 2014: Linear and nonlinear trends of extreme temperatures in Korea. Atmosphere, 24, 379-390 (in Korean with English abstract). https://doi.org/10.14191/Atmos.2014.24.3.379
- Koenker, R., and K. F. Hallock, 2001: Quantile regression. J. Econ. Perspect., 15, 143-156. https://doi.org/10.1257/jep.15.4.143
- Lim, S.-M., S.-W. Yeh, and G.-R. Kim, 2012: Analysis on the Relationship between the Korean Temperature and the Atmospheric Circulation over the Northern Hemisphere during winter. Atmosphere, 22, 187-197 (in Korean with English abstract). https://doi.org/10.14191/Atmos.2012.22.2.187
- Methven, J., 2015: Potential vorticity in warm conveyor belt outflow. Quart. J. Roy. Meteor. Soc., 141, 1065-1071, doi:10.1002/qj.2393.
- Ryoo S.-B., and W.-T. Kwon, 2002: Climatological characteristics of cold winter and cold days over South Korea. Atmosphere, 12, 288-291 (in Korean).
- Ryoo S.-B., J.-G. Jhun, W.-T. Kwon, and S.-K. Min, 2002: Climatological aspects of warm and cold winters in South Korea. Korean J. Atmos. Sci., 5, 29-37.
- Schemm, S., and H. Wernli, 2014: The linkage between the warm and the cold conveyor belts in an idealized extratropical cyclone. J. Atmos. Sci., 71, 1443-1459, doi:10.1175/JAS-D-13-0177.1.
- Stoelinga, M. T., 1996: A potential vorticity-based study of the role of diabatic heating and friction in a numerically simulated baroclinic cyclone. Mon. Wea. Rev., 124, 849-874. https://doi.org/10.1175/1520-0493(1996)124<0849:APVBSO>2.0.CO;2
- Wang, L., and W. Chen, 2010: How well do existing indices measure the strength of the East Asian Winter Monsoon? Adv. Atmos. Sci., 27, 855-870, doi:10.1007/s00376-009-9094-3.
- Yoo, Y.-E., S.-W. Son, H.-S. Kim, and J.-H. Jeong, 2015: Synoptic Characteristics of Cold Days over South Korea and Their Relationship with Large-Scale Climate Variability. Atmosphere, 25, 435-447, doi:10.14191/Atmos.2015.25.3.435 (in Korean with English abstract).
- Yu, L., X. Jin, and R. A. Weller, 2008: Multidecade Global Flux Datasets from the Objectively Analyzed Air-sea Fluxes (OAFlux) Project: Latent and sensible heat fluxes, ocean evaporation, and related surface meteorological variables, Woods Hole Oceanographic Institution. OAFlux Project Technical Report OA-2008-1, 64 pp.