The Australian Summer Monsoon Circulation during AMEX Phase II

Abstract

The major field phase of the Australian Monsoon Experiment (AMEX Phase II) was conducted over northern Australia from 1 0 January to 1 5 February 1987. It was based on the collection of high-density tropical upper air soundings and radar data at 12 special observation sites. These were complemented by satellite and surface data, the existing upper air network, and two simultaneous aircraft based tropical experiments. This paper describes the data collected in AMEX and the mean and transient structure of the Australian monsoon circulation during the experiment. Mean soundings across the network am compared with each other and with soundings from other commonly used research datasets. It is shown that an active monsoon trough lay through the AMEX network, and that the associated convection is located within one of the three global tropical heat sources. Active and inactive periods of monsoon behavior are defined. Monsoon onset occurred within the period of the experiment and four tropical cyclones existed within the enhanced network. Two of these developed inside an array of radiosondes surrounding the Gulf of Carpentaria.