Diurnal Rainfall Propagation Relate to Cold Surge-Cold Tongue Interaction over the Northern Coast of West Java

Abstract

Interaction of the diurnal cycle of rainfall systems between land and sea were investigated by hourly rainfall of 3B41RT TRMM dataset, daily SST dataset from OISST, 6- hourly wind and temperature data from NCEP-NCAR Reanalysis, during period of NDJFM 2000-2016. The results showed that the diurnal cycle of rainfall from sea to land and from land to sea randomly occurred on four combinations of CENS-CT, NCENS-CT, CENS-NCT, NCENS-NCT. Diurnal rainfall in northern coast of West Java for normal conditions without CENS-CT has two maximas, namely late afternoon and early morning rainfall. CENS-CT interaction changes the normal diurnal rainfall pattern into three diurnal rainfall systems: diurnal rainfall with propagate B pattern which is identified by the afternoon continous to morning rainfall and there is an offshore propagation from sea to land that occurred in the morning, diurnal rainfall with a nonpropagate pattern, namely morning rainfall which has increased intensity and duration while afternoon rainfall is minimum, diurnal rainfall with propagate A pattern which experienced rainfall from land to sea and there was a merger between the afternoon rainfall system over the land and the morning rainfall system over the sea.