CHARACTERISTICS OF THE NORTHERN HEMISPHERE 500hPa DIABATIC HEAT FLOW FIELD IN YEARS OF EL NINO AND ANTI-EL NINO

In this paper,by using spectral method,the monthly-and seasonal-scale atmospheric diabatic heat flow(ADHF) departure fields are diagnosed in the period of 1964-1985 with 6 El Nino years and 6 anti-El Nino years over the Northern hemisphere(NH).The results show that El Nino phenomena have pronounced influence on the ADHF departure fields.The response of atmosphere exhibits a preferred arrangement of organizing positive and negative departure centers at low,middle and high latitudes.In anti-El Nino years,the response has the same forms as in El Nino years,but departure centers are opposite in phase.Furthermore,ADHF departure shows low-frequency oscillation in El Nino years and anti-El Nino years.The center of difference in departure between El Nino and anti-El Nino years displays a bimonthly oscillation.Finally,through air-sea correlation analysis,it is pointed out that the SST anomaly is the most important cause for ADHF anomaly.