17.Įstimate of predictability for (a) zonal winds at 850 hPa and (b) precipitation during northern summer (JJAS). 14, but for an annually varying forcing, F 0 = 5.6, F 1 = 2.5, and G = 1.18, that includes the chaotic regime shown in Fig. Power spectrum is plotted as power multiplied by frequency vs period.
#Roadblock definition series#
(left) Time series of X and Y for constant forcing F 0 = 7.62, F 1 = 0.0, and G = 1.18 for a typical 10-yr period from a 200-yr simulation with (right) corresponding spectra. Correlations between the two are indicated in each panel.
#Roadblock definition iso#
ISO activity is defined as standard deviation of 10–90-day filtered precipitation. Both quantities are averaged over 0°−30°N, 60°–100☎. Relationship between IAV of ISO activity in precipitation during northern summer (1 Jun–30 Sep) and that of (a) JJAS seasonal mean precipitation and (b) IAV of the AC (JJA minus DJF) of precipitation. (b) Same as in (a), but for eight weak monsoon years from NCEP–NCAR reanalysis. Composite of strong minus weak JJAS precipitation based on eight strong (1958, 1959, 1961, 1970, 1978, 1980, 1981, and 1994) and eight weak (1962, 1964, 1965, 1966, 1972, 1974, 1987, and 2002) years.įrequency distribution of 10–90-day filtered precipitation anomalies averaged over 10°–30°N, 70°–90☎ for (a) eight strong monsoon years between 1 Jun and 30 Sep normalized by its own standard deviation. (b) Spatial pattern of dominant IAV of Asian monsoon. Composite of all active minus break conditions, 10–90-day filtered precipitation between 1 Jun and 30 Sep for the period between 19. (a) Spatial pattern of dominant ISO mode in precipitation (mm day −1). (b) Julian day of each year (1950–2002) when TTN becomes greater than TTS against corresponding MOK. (a) Climatological evolution of TTN and TTS over the year calculated from daily NCEP–NCAR reanalysis between 19. Light, heavy, and dark shadings indicate, respectively, the OLR values between 230 and 215, 215 and 200, and less than 200 W m −2. The projection of the subtropical anticyclone ridgeline ( u = 0) and OLR (W m −2) at the levels from 850 to 200 hPa during the season transition (from the third pentad of April to the second pentad of June): (a) 11–15 Apr, (b) 16–20 Apr, (c) 21–25 Apr, (d) 26–30 Apr, (e) 1–5 May, (f) 6–10 May, (g) 11–15 May, (h) 16–20 May, (i) 21–25 May, (j) 26–31 May, (k) 1–5 Jun, and (l) 6–10 Jun. (c) The 21-yr sliding window correlation between the two variables in (b). (b) Anomalous AC of precipitation over India between 18 and Niño-3 SSTA during JJA (dotted scale on right in ☌). (a) Amplitude of AC (JJA − DJF) of zonal winds at 850 hPa in the north central Arabian Sea averaged over 7°–17°N, 40°–80☎ from NCEP–NCAR reanalysis between 19 (solid scale on left in m s −1) and Niño-3 SSTA during JJA (dotted scale on right in ☌).
Schematic diagram of two successive monsoon years for the coupled ENSO–monsoon system (from Ailikun and Yasunari 2001, © Meteorological Society of Japan).
Values greater than 6 mm day −1 are shaded in (a) and (b).Contour interval is 1 mm day −1 in (c) and (d), and minimum contours are +0.5 mm day −1 (solid) and −0.5 mm day −1 (dashed). (c), (d) Same as in (a) and (b), respectively, but for contribution from the fast annual cycle. (c) Annual evolution of climatological mean temperature averaged between 200 and 600 hPa and averaged over the Asian monsoon region between 30° and 110☎ in ☌.Īmplitude of the climatological mean (a) slow annual cycle, (b) fast annual cycle of precipitation (mm day −1), and (c) ratio between the slow and fast annual cycles.Ĭontribution of the slow annual cycle to the seasonal evolution of ITCZ (precipitation mm day −1) over (a) the Indian region (70°–90☎) and (b) the Australian monsoon region (120°–140☎). Precipitation more than 4 mm day −1 is shaded.Īmplitude of climatological mean AC as defined by the std dev of climatological monthly means of (a) precipitation (mm day −1), (b) zonal wind at 850 hPa (m s −1), and (c) meridional wind at 850 hPa (m s −1).Īnnual evolution of the ITCZ over, (a) the Indian monsoon region, defined by climatological precipitation (mm day −1) averaged between 70° and 90☎ and (b) the Australian monsoon region, defined by climatological precipitation (mm day −1) averaged between 120° and 140☎. Scale for wind vectors is shown at the bottom of each panel. (a) Climatological mean JJA precipitation from CMAP and 850-hPa winds from NCEP–NCAR reanalysis. Seasonal cycle of precipitation (mm day −1) and low-level winds (m s −1) over the Asian monsoon region. A schematic picture of factors contributing to the predictability of the seasonal mean Asian monsoon.
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