Summary of Abstract Submission

Abstract Submission No. IO50-06-0022PresentationOral

DO MIDDLE-EAST DUST AFFECT RAINWATER COMPOSITION AND SENSITIVE ECOSYSTEMS OVER INDIA?

V Ramaswamy*1, P.M. Muraleedharan1, Prakash Babu1

1 CSIR-NIO, India

ABSTRACT :

The southwest monsoon winds bring heavy rain and clean maritime air over the Indian Peninsula resulting in a substantial reduction in ambient surface- aerosol concentrations. During the same period the Shamal Winds lift dust from the Middle-East and transport it towards the Arabian Sea. In this study we show that the dry, warm and dusty Shamal Wind override the low-level jet (Findlater Jet) during the summer monsoon and transports large quantity of dust at heights between 1.5 km and 5 km over the Indian Peninsula. Part of this dust is wet-deposited along the Western Ghats of India in an area underlain by a dense population and sensitive ecosystems. Our measurements show that dust from the Middle-East neutralizes the acidity and increases the pH of rainwater over India. After the Shamal winds subside by end of August, the composition of rainwater reverts from alkaline to acidic range due to soluble ions derived from local carbonaceous aerosols. The dust and carbonaceous aerosols provide phosphorus and nitrogen which can impact the sensitive Western Ghat biodiversity hotspot, the coastal anoxic ecosystem and rainwater harvesting over the Indian Peninsula.