Blocking highs over Asia and monsoon droughts over India

Changes in the large‐scale features associated with the Indian summer monsoon in the recent decades

“…In Case-II, however, clearly suggests the influence of short waves (wavenumber 7) on the Indian monsoon with alternate highs and lows. The low pressure anomaly over NW of Caspian Sea and Central Asia suggest existence of two blocking ridges during severe drought years of the ISMR (Raman and Rao, 1981).…”

“…The cyclonic circulation intensifying monsoon circulation which further intensifying over the Tibetan high so, there will be a positive feedback. In the opposite case, the ridge over the Black Sea and Central Asia may acts as blocking ridges (Raman and Rao, 1981) and the trough over NW of India may weaken over the Tibetan high and hence weaken the monsoon circulation (Ramaswamy, 1962).…”

Variation in the Atmospheric Circulation over Asia and the Western Pacific Associated with the 40-day Oscillation of the Indian Summer Monsoon

“…Raman et al (1980), Raman and Rao (1981) and Tanaka (1983) pointed out that the blocking ridge over the Eurasian continent appeared before the break in the monsoon. Moreover, M. Murakami (1984Murakami ( , 1985 showed that the anomalous wind (the 30-60 day component) appeared distinctly in the middle and high latitudes.…”

Interaction Between the Active-Break Cycle of the Summer Monsoon and the Circulation in Eurasia and the Western Pacific

“…Recently, Raman and Rao (1981) have shown that the break monsoon in India is preceded by the blocking highs in west Asia (40-60*N, 50*E) and east Asia (35-70*N, 90-115*E). Tanaka (1982) has shown that a blocking high develops to the north of the Caspian Sea (near 50*N, 50*E) when the tropical easterly jet stream is weak in July and August.…”