Air and water vapour transport across the equator in Western Indian Ocean during Northern Summer

Abstract

Magnitudes of net total northward fluxes of air and water vapour into the Arabian Sea across an equatorial section extending from 42" E to 75" E and from sea surface to the 450 mb level are computed

The use of global circulation models in the study of the Indian monsoon

“…'Observations suggest that a substantial part of the moisture required for monsoon precipitation is supplied by southwesterlies over the Arabian Sea which are a continuation of the southeast trade winds of the Southern Hemisphere (Saha, 1970 and. It is not clear how much of the moisture comes as a result of evaporation over the Arabian Sea.'…”

Structure of the marine boundary layer over north western Indian Ocean during 1983 summer monsoon

“…Several investigators (Pisharoty, 1965;Sikka and Mathur, 1965;Desai, 1975;Findlater, 1969;Saha, 1970;Saha and Bavadekar, 1973;Ramamurthy et al, 1976;Pant 1976Pant & 1978Ghosh et al, 1978;Rao and Van De Boogaard, 1981;Howland and Sikdar, 1983;Ray and Bedi, 1985;Ramesh Kumar et al, 1986;Sadhuram et al, 1987, Holt andSethuraman, 1987;Cadet and Greco, 1987;Sadhuram and Ramesh Kumar, 1988) have looked into various aspects of the monsoon such as structure of the atmospheric boundary layer, cross-equatorial flux, the role of the Somali jet, the role of the southern hemispheric equatorial trough, heat and momentum fluxes across the air-sea interface and sea surface temperature anomalies over the Arabian Sea. The monsoon circulation has also been found to be an important component of the global general circulation.…”

Tropical Circulation Systems and Monsoons

“…However, several studies (e.g., Findlater, 1969a,b;Saha, 1970;Wang and Leftwich, 1984;Sun, 2002) have emphasized that the main artery for supply of moisture for Southern Asia rainfall including that over Eastern Asia is that via the Somali Monsoon Current in the western Indian Ocean. Additional moisture supplies for rainfall over Eastern Asia are those from cross-equatorial airflow via routes over the Maritime Continent and from the tradewinds originating in the subtropical high pressure over the western Pacific Ocean, as shown schematically in Fig.…”

“…For comparison, similar information available in respect of the Western Indian Ocean region and the equator as a whole is also included in the table. Lower (sfc-300 hPa) -3.14 +2.68 (Saha and Saha, 2000) Upper (300-50 hPa) +1.93 -4.00 (ii) Western Indian Ocean (42-75 • E) (Findlater, 1969a, b) Lower (sfc-400 hPa) -2.28 +7.68 (Saha, 1970) Lower (sfc-400 hPa) +5.03 (iii) Estimated total across the whole Lower (sfc-500 hPa) -18.49 +16.20 equator (5 • N-5 • S) (Rao, 1964) Table 7.1 highlights the magnitudes and direction of the seasonal movements of airmasses between the hemispheres during both Australian summer (January/February) and winter (July/August). According to Table 7.1, during February, the total cross-equatorial flux amounts to -3.14 in the lower troposphere and 2.68 in the upper troposphere.…”

“…Over most parts of the globe, the main source of moisture for monsoon rainfall in the summer hemisphere is the cool, moist tradewinds of the winter hemisphere which after crossing the equator in narrow longitudinal segments converge into the ITCZ of the summer hemisphere (e.g., Simpson, 1921;Findlater, 1969a,b;Saha, 1970).…”