Teleconnections between El Niño event and Tropospheric Trace Gases over Indonesia
Diego Loyola(1), Pieter Valks(1), Thomas Ruppert(1), Andreas Richter(2), Thomas Wagner(3), Werner Thomas(4), Ronald van der A(5) and Robert Meisner(1)
(1) DLR, Oberpfaffenhofen, D-82234 Wessling, Germany
(2) University of Bremen, P.O. Box 33 04 40, D-28334 Bremen, Germany
(3) University of Heidelberg, Im Neuenheimer Feld 229, 69120 Heidelberg , Germany
(4) Deutscher Wetterdienst , P.O. Box 10 04 65, D-63004 Offenbach, Germany
(5) KNMI, P.O.Box 201, 3730 AE De Bilt, Netherlands
The last major El Niño event of 1997/1998 caused dry conditions over the Indonesian area that were followed by large scale forest and savannah fires over Kalimantan, Sumatra, Java, and parts of Irian Jaya.
Biomass burning was most intense between August and October 1997, and large amounts of ozone precursors, such as nitrogen oxides, carbon monoxide and hydrocarbons were emitted into the atmosphere.
In this work, we use GOME measurements to study the teleconnections between the El Niño event during 1997 and trace gases over Indonesia.
Cloud anomalies measured by GOME show a decrease of clouds (cloud fraction) in October 1997 over the Indonesian region, with an increase of cloud-top pressure and cloud optical thickness. Similar results are observed on the global distribution of the GOME derived water vapour abundance in the atmosphere. The dry conditions induced fires over this region; the fires detected with ATSR-2 correlate well with the aerosol index derived by GOME. The large scale biomass burning over Kalimantan and Sumatra resulted in highly elevated tropospheric NO2, Formaldehyde and tropospheric ozone column, as shown by GOME.
This change of the atmospheric composition over large parts in Indonesia demonstrates the strong connection between the El Niño phenomenon in the Western Pacific and extreme (dry) weather conditions in the Eastern Pacific Ocean and neighbouring countries. We could show that GOME data can be used to measure simultaneously cloud, water vapour, aerosols and reactive trace gases in the troposphere under such atmospheric conditions.
Keywords: ESA European
Space Agency - Agence spatiale europeenne,
observation de la terre, earth observation,
satellite remote sensing,
teledetection, geophysique, altimetrie, radar,
chimique atmospherique, geophysics, altimetry, radar,